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Water pollution: an introduction

by Chris Woodford . Last updated: October 1, 2023.

O ver two thirds of Earth's surface is covered by water ; less than a third is taken up by land. As Earth's population continues to grow, people are putting ever-increasing pressure on the planet's water resources. In a sense, our oceans, rivers , and other inland waters are being "squeezed" by human activities—not so they take up less room, but so their quality is reduced. Poorer water quality means water pollution .

We know that pollution is a human problem because it is a relatively recent development in the planet's history: before the 19th century Industrial Revolution, people lived more in harmony with their immediate environment. As industrialization has spread around the globe, so the problem of pollution has spread with it. When Earth's population was much smaller, no one believed pollution would ever present a serious problem. It was once popularly believed that the oceans were far too big to pollute. Today, with around 7 billion people on the planet, it has become apparent that there are limits. Pollution is one of the signs that humans have exceeded those limits.

Photo: Stormwater pollution entering a river from a drain. Photo by Peter C Van Metre courtesy of US Geological Survey .

What is water pollution?

Water pollution can be defined in many ways. Usually, it means one or more substances have built up in water to such an extent that they cause problems for animals or people. Oceans, lakes, rivers, and other inland waters can naturally clean up a certain amount of pollution by dispersing it harmlessly. If you poured a cup of black ink into a river, the ink would quickly disappear into the river's much larger volume of clean water. The ink would still be there in the river, but in such a low concentration that you would not be able to see it. At such low levels, the chemicals in the ink probably would not present any real problem. However, if you poured gallons of ink into a river every few seconds through a pipe, the river would quickly turn black. The chemicals in the ink could very quickly have an effect on the quality of the water. This, in turn, could affect the health of all the plants, animals, and humans whose lives depend on the river.

Photo: Pollution means adding substances to the environment that don't belong there—like the air pollution from this smokestack. Pollution is not always as obvious as this, however.

Thus, water pollution is all about quantities : how much of a polluting substance is released and how big a volume of water it is released into. A small quantity of a toxic chemical may have little impact if it is spilled into the ocean from a ship. But the same amount of the same chemical can have a much bigger impact pumped into a lake or river, where there is less clean water to disperse it.

"The introduction by man, directly or indirectly, of substances or energy into the marine environment (including estuaries) resulting in such deleterious effects as harm to living resources, hazards to human health, hindrance to marine activities, including fishing, impairment of quality for use of sea water and reduction of amenities." [1]

What are the main types of water pollution?

When we think of Earth's water resources, we think of huge oceans, lakes, and rivers. Water resources like these are called surface waters . The most obvious type of water pollution affects surface waters. For example, a spill from an oil tanker creates an oil slick that can affect a vast area of the ocean.

Photo: Detergent pollution entering a river—an example of surface water pollution. Photo courtesy of US Fish & Wildlife Service Photo Library.

Not all of Earth's water sits on its surface, however. A great deal of water is held in underground rock structures known as aquifers, which we cannot see and seldom think about. Water stored underground in aquifers is known as groundwater . Aquifers feed our rivers and supply much of our drinking water. They too can become polluted, for example, when weed killers used in people's gardens drain into the ground. Groundwater pollution is much less obvious than surface-water pollution, but is no less of a problem. In 1996, a study in Iowa in the United States found that over half the state's groundwater wells were contaminated with weed killers. You might think things would have improved since then, but, two decades on, all that's really changed is the name of the chemicals we're using. Today, numerous scientific studies are still finding weed killers in groundwater in worrying quantities: a 2012 study discovered glyphosate in 41 percent of 140 groundwater samples from Catalonia, Spain; scientific opinion differs on whether this is safe or not. [2]

Surface waters and groundwater are the two types of water resources that pollution affects. There are also two different ways in which pollution can occur. If pollution comes from a single location, such as a discharge pipe attached to a factory, it is known as point-source pollution . Other examples of point source pollution include an oil spill from a tanker, a discharge from a smoke stack (factory chimney), or someone pouring oil from their car down a drain. A great deal of water pollution happens not from one single source but from many different scattered sources. This is called nonpoint-source pollution .

When point-source pollution enters the environment, the place most affected is usually the area immediately around the source. For example, when a tanker accident occurs, the oil slick is concentrated around the tanker itself and, in the right ocean conditions, the pollution disperses the further away from the tanker you go. This is less likely to happen with nonpoint source pollution which, by definition, enters the environment from many different places at once.

Sometimes pollution that enters the environment in one place has an effect hundreds or even thousands of miles away. This is known as transboundary pollution . One example is the way radioactive waste travels through the oceans from nuclear reprocessing plants in England and France to nearby countries such as Ireland and Norway.

How do we know when water is polluted?

Some forms of water pollution are very obvious: everyone has seen TV news footage of oil slicks filmed from helicopters flying overhead. Water pollution is usually less obvious and much harder to detect than this. But how can we measure water pollution when we cannot see it? How do we even know it's there?

There are two main ways of measuring the quality of water. One is to take samples of the water and measure the concentrations of different chemicals that it contains. If the chemicals are dangerous or the concentrations are too great, we can regard the water as polluted. Measurements like this are known as chemical indicators of water quality. Another way to measure water quality involves examining the fish, insects, and other invertebrates that the water will support. If many different types of creatures can live in a river, the quality is likely to be very good; if the river supports no fish life at all, the quality is obviously much poorer. Measurements like this are called biological indicators of water quality.

What are the causes of water pollution?

Most water pollution doesn't begin in the water itself. Take the oceans: around 80 percent of ocean pollution enters our seas from the land. [16] Virtually any human activity can have an effect on the quality of our water environment. When farmers fertilize the fields, the chemicals they use are gradually washed by rain into the groundwater or surface waters nearby. Sometimes the causes of water pollution are quite surprising. Chemicals released by smokestacks (chimneys) can enter the atmosphere and then fall back to earth as rain, entering seas, rivers, and lakes and causing water pollution. That's called atmospheric deposition . Water pollution has many different causes and this is one of the reasons why it is such a difficult problem to solve.

With billions of people on the planet, disposing of sewage waste is a major problem. According to 2017 figures from the World Health Organization, some 2 billion people (about a quarter of the world's population) don't have access to safe drinking water or the most basic sanitation, 3.4 billion (60 people of the population) lack "safely managed" sanitation (unshared, with waste properly treated). Although there have been great improvements in securing access to clean water, relatively little, genuine progress has been made on improving global sanitation in the last decade. [20] Sewage disposal affects people's immediate environments and leads to water-related illnesses such as diarrhea that kills 525,000 children under five each year. [3] (Back in 2002, the World Health Organization estimated that water-related diseases could kill as many as 135 million people by 2020; in 2019, the WHO was still estimating the annual death toll from poor water and sanitation at over 800,000 people a year.) In developed countries, most people have flush toilets that take sewage waste quickly and hygienically away from their homes.

Yet the problem of sewage disposal does not end there. When you flush the toilet, the waste has to go somewhere and, even after it leaves the sewage treatment works, there is still waste to dispose of. Sometimes sewage waste is pumped untreated into the sea. Until the early 1990s, around 5 million tons of sewage was dumped by barge from New York City each year. [4] According to 2002 figures from the UK government's Department for the Environment, Food, and Rural Affairs (DEFRA), the sewers of Britain collect around 11 billion liters of waste water every day; there are still 31,000 sewage overflow pipes through which, in certain circumstances, such as heavy storms, raw sewage is pumped untreated into the sea. [5] The New River that crosses the border from Mexico into California once carried with it 20–25 million gallons (76–95 million liters) of raw sewage each day; a new waste water plant on the US-Mexico border, completed in 2007, substantially solved that problem. [6] Unfortunately, even in some of the richest nations, the practice of dumping sewage into the sea continues. In early 2012, it was reported that the tiny island of Guernsey (between Britain and France) has decided to continue dumping 16,000 tons of raw sewage into the sea each day.

In theory, sewage is a completely natural substance that should be broken down harmlessly in the environment: 90 percent of sewage is water. [7] In practice, sewage contains all kinds of other chemicals, from the pharmaceutical drugs people take to the paper , plastic , and other wastes they flush down their toilets. When people are sick with viruses, the sewage they produce carries those viruses into the environment. It is possible to catch illnesses such as hepatitis, typhoid, and cholera from river and sea water.

Photo: Nutrients make crops grow, but cause pollution when they seep into rivers and other watercourses. Photo courtesy of US Department of Agriculture (Flickr) .

Suitably treated and used in moderate quantities, sewage can be a fertilizer: it returns important nutrients to the environment, such as nitrogen and phosphorus, which plants and animals need for growth. The trouble is, sewage is often released in much greater quantities than the natural environment can cope with. Chemical fertilizers used by farmers also add nutrients to the soil, which drain into rivers and seas and add to the fertilizing effect of the sewage. Together, sewage and fertilizers can cause a massive increase in the growth of algae or plankton that overwhelms huge areas of oceans, lakes, or rivers. This is known as a harmful algal bloom (also known as an HAB or red tide, because it can turn the water red). It is harmful because it removes oxygen from the water that kills other forms of life, leading to what is known as a dead zone . The Gulf of Mexico has one of the world's most spectacular dead zones. Each summer, according to studies by the NOAA , it typically grows to an area of around 5500–6500 square miles (14,000–16,800 square kilometers), which is about the same size as the state of Connecticut. [21]

Waste water

A few statistics illustrate the scale of the problem that waste water (chemicals washed down drains and discharged from factories) can cause. Around half of all ocean pollution is caused by sewage and waste water. Each year, the world generates perhaps 5–10 billion tons of industrial waste, much of which is pumped untreated into rivers, oceans, and other waterways. [8] In the United States alone, around 400,000 factories take clean water from rivers, and many pump polluted waters back in their place. However, there have been major improvements in waste water treatment recently. Since 1970, in the United States, the Environmental Protection Agency (EPA) has invested about $70 billion in improving water treatment plants that, as of 2021, serve around 90 percent of the US population (compared to just 69 percent in 1972). However, another $271 billion is still needed to update and upgrade the system. [15]

Factories are point sources of water pollution, but quite a lot of water is polluted by ordinary people from nonpoint sources; this is how ordinary water becomes waste water in the first place. Virtually everyone pours chemicals of one sort or another down their drains or toilets. Even detergents used in washing machines and dishwashers eventually end up in our rivers and oceans. So do the pesticides we use on our gardens. A lot of toxic pollution also enters waste water from highway runoff . Highways are typically covered with a cocktail of toxic chemicals—everything from spilled fuel and brake fluids to bits of worn tires (themselves made from chemical additives) and exhaust emissions. When it rains, these chemicals wash into drains and rivers. It is not unusual for heavy summer rainstorms to wash toxic chemicals into rivers in such concentrations that they kill large numbers of fish overnight. It has been estimated that, in one year, the highway runoff from a single large city leaks as much oil into our water environment as a typical tanker spill. Some highway runoff runs away into drains; others can pollute groundwater or accumulate in the land next to a road, making it increasingly toxic as the years go by.

Chemical waste

Detergents are relatively mild substances. At the opposite end of the spectrum are highly toxic chemicals such as polychlorinated biphenyls (PCBs) . They were once widely used to manufacture electronic circuit boards , but their harmful effects have now been recognized and their use is highly restricted in many countries. Nevertheless, an estimated half million tons of PCBs were discharged into the environment during the 20th century. [9] In a classic example of transboundary pollution, traces of PCBs have even been found in birds and fish in the Arctic. They were carried there through the oceans, thousands of miles from where they originally entered the environment. Although PCBs are widely banned, their effects will be felt for many decades because they last a long time in the environment without breaking down.

Another kind of toxic pollution comes from heavy metals , such as lead, cadmium, and mercury. Lead was once commonly used in gasoline (petrol), though its use is now restricted in some countries. Mercury and cadmium are still used in batteries (though some brands now use other metals instead). Until recently, a highly toxic chemical called tributyltin (TBT) was used in paints to protect boats from the ravaging effects of the oceans. Ironically, however, TBT was gradually recognized as a pollutant: boats painted with it were doing as much damage to the oceans as the oceans were doing to the boats.

The best known example of heavy metal pollution in the oceans took place in 1938 when a Japanese factory discharged a significant amount of mercury metal into Minamata Bay, contaminating the fish stocks there. It took a decade for the problem to come to light. By that time, many local people had eaten the fish and around 2000 were poisoned. Hundreds of people were left dead or disabled. [10]

Radioactive waste

People view radioactive waste with great alarm—and for good reason. At high enough concentrations it can kill; in lower concentrations it can cause cancers and other illnesses. The biggest sources of radioactive pollution in Europe are two factories that reprocess waste fuel from nuclear power plants : Sellafield on the north-west coast of Britain and Cap La Hague on the north coast of France. Both discharge radioactive waste water into the sea, which ocean currents then carry around the world. Countries such as Norway, which lie downstream from Britain, receive significant doses of radioactive pollution from Sellafield. [19] The Norwegian government has repeatedly complained that Sellafield has increased radiation levels along its coast by 6–10 times. Both the Irish and Norwegian governments continue to press for the plant's closure. [11]

Oil pollution

Photo: Oil-tanker spills are the most spectacular forms of pollution and the ones that catch public attention, but only a fraction of all water pollution happens this way. Photo by Lamar Gore courtesy of US Fish & Wildlife Service Photo Library and US National Archive .

When we think of ocean pollution, huge black oil slicks often spring to mind, yet these spectacular accidents represent only a tiny fraction of all the pollution entering our oceans. Even considering oil by itself, tanker spills are not as significant as they might seem: only 12 percent of the oil that enters the oceans comes from tanker accidents; over 70 percent of oil pollution at sea comes from routine shipping and from the oil people pour down drains on land. [12] However, what makes tanker spills so destructive is the sheer quantity of oil they release at once — in other words, the concentration of oil they produce in one very localized part of the marine environment. The biggest oil spill in recent years (and the biggest ever spill in US waters) occurred when the tanker Exxon Valdez broke up in Prince William Sound in Alaska in 1989. Around 12 million gallons (44 million liters) of oil were released into the pristine wilderness—enough to fill your living room 800 times over! Estimates of the marine animals killed in the spill vary from approximately 1000 sea otters and 34,000 birds to as many as 2800 sea otters and 250,000 sea birds. Several billion salmon and herring eggs are also believed to have been destroyed. [13]

If you've ever taken part in a community beach clean, you'll know that plastic is far and away the most common substance that washes up with the waves. There are three reasons for this: plastic is one of the most common materials, used for making virtually every kind of manufactured object from clothing to automobile parts; plastic is light and floats easily so it can travel enormous distances across the oceans; most plastics are not biodegradable (they do not break down naturally in the environment), which means that things like plastic bottle tops can survive in the marine environment for a long time. (A plastic bottle can survive an estimated 450 years in the ocean and plastic fishing line can last up to 600 years.)

While plastics are not toxic in quite the same way as poisonous chemicals, they nevertheless present a major hazard to seabirds, fish, and other marine creatures. For example, plastic fishing lines and other debris can strangle or choke fish. (This is sometimes called ghost fishing .) About half of all the world's seabird species are known to have eaten plastic residues. In one study of 450 shearwaters in the North Pacific, over 80 percent of the birds were found to contain plastic residues in their stomachs. In the early 1990s, marine scientist Tim Benton collected debris from a 2km (1.5 mile) length of beach in the remote Pitcairn islands in the South Pacific. His study recorded approximately a thousand pieces of garbage including 268 pieces of plastic, 71 plastic bottles, and two dolls heads. [14]

Alien species

Most people's idea of water pollution involves things like sewage, toxic metals, or oil slicks, but pollution can be biological as well as chemical. In some parts of the world, alien species are a major problem. Alien species (sometimes known as invasive species ) are animals or plants from one region that have been introduced into a different ecosystem where they do not belong. Outside their normal environment, they have no natural predators, so they rapidly run wild, crowding out the usual animals or plants that thrive there. Common examples of alien species include zebra mussels in the Great Lakes of the USA, which were carried there from Europe by ballast water (waste water flushed from ships ). The Mediterranean Sea has been invaded by a kind of alien algae called Caulerpa taxifolia . In the Black Sea, an alien jellyfish called Mnemiopsis leidyi reduced fish stocks by 90 percent after arriving in ballast water. In San Francisco Bay, Asian clams called Potamocorbula amurensis, also introduced by ballast water, have dramatically altered the ecosystem. In 1999, Cornell University's David Pimentel estimated that alien invaders like this cost the US economy $123 billion a year; in 2014, the European Commission put the cost to Europe at €12 billion a year and "growing all the time. [18]

Other forms of pollution

These are the most common forms of pollution—but by no means the only ones. Heat or thermal pollution from factories and power plants also causes problems in rivers. By raising the temperature, it reduces the amount of oxygen dissolved in the water, thus also reducing the level of aquatic life that the river can support. Another type of pollution involves the disruption of sediments (fine-grained powders) that flow from rivers into the sea. Dams built for hydroelectric power or water reservoirs can reduce the sediment flow. This reduces the formation of beaches, increases coastal erosion (the natural destruction of cliffs by the sea), and reduces the flow of nutrients from rivers into seas (potentially reducing coastal fish stocks). Increased sediments can also present a problem. During construction work, soil, rock, and other fine powders sometimes enters nearby rivers in large quantities, causing it to become turbid (muddy or silted). The extra sediment can block the gills of fish, effectively suffocating them. Construction firms often now take precautions to prevent this kind of pollution from happening.

What are the effects of water pollution?

Some people believe pollution is an inescapable result of human activity: they argue that if we want to have factories, cities, ships, cars, oil, and coastal resorts, some degree of pollution is almost certain to result. In other words, pollution is a necessary evil that people must put up with if they want to make progress. Fortunately, not everyone agrees with this view. One reason people have woken up to the problem of pollution is that it brings costs of its own that undermine any economic benefits that come about by polluting.

Take oil spills, for example. They can happen if tankers are too poorly built to survive accidents at sea. But the economic benefit of compromising on tanker quality brings an economic cost when an oil spill occurs. The oil can wash up on nearby beaches, devastate the ecosystem, and severely affect tourism. The main problem is that the people who bear the cost of the spill (typically a small coastal community) are not the people who caused the problem in the first place (the people who operate the tanker). Yet, arguably, everyone who puts gasoline (petrol) into their car—or uses almost any kind of petroleum-fueled transport—contributes to the problem in some way. So oil spills are a problem for everyone, not just people who live by the coast and tanker operates.

Sewage is another good example of how pollution can affect us all. Sewage discharged into coastal waters can wash up on beaches and cause a health hazard. People who bathe or surf in the water can fall ill if they swallow polluted water—yet sewage can have other harmful effects too: it can poison shellfish (such as cockles and mussels) that grow near the shore. People who eat poisoned shellfish risk suffering from an acute—and sometimes fatal—illness called paralytic shellfish poisoning. Shellfish is no longer caught along many shores because it is simply too polluted with sewage or toxic chemical wastes that have discharged from the land nearby.

Pollution matters because it harms the environment on which people depend. The environment is not something distant and separate from our lives. It's not a pretty shoreline hundreds of miles from our homes or a wilderness landscape that we see only on TV. The environment is everything that surrounds us that gives us life and health. Destroying the environment ultimately reduces the quality of our own lives—and that, most selfishly, is why pollution should matter to all of us.

How can we stop water pollution?

There is no easy way to solve water pollution; if there were, it wouldn't be so much of a problem. Broadly speaking, there are three different things that can help to tackle the problem—education, laws, and economics—and they work together as a team.

Making people aware of the problem is the first step to solving it. In the early 1990s, when surfers in Britain grew tired of catching illnesses from water polluted with sewage, they formed a group called Surfers Against Sewage to force governments and water companies to clean up their act. People who've grown tired of walking the world's polluted beaches often band together to organize community beach-cleaning sessions. Anglers who no longer catch so many fish have campaigned for tougher penalties against factories that pour pollution into our rivers. Greater public awareness can make a positive difference.

One of the biggest problems with water pollution is its transboundary nature. Many rivers cross countries, while seas span whole continents. Pollution discharged by factories in one country with poor environmental standards can cause problems in neighboring nations, even when they have tougher laws and higher standards. Environmental laws can make it tougher for people to pollute, but to be really effective they have to operate across national and international borders. This is why we have international laws governing the oceans, such as the 1982 UN Convention on the Law of the Sea (signed by over 120 nations), the 1972 London (Dumping) Convention , the 1978 MARPOL International Convention for the Prevention of Pollution from Ships , and the 1998 OSPAR Convention for the Protection of the Marine Environment of the North East Atlantic . The European Union has water-protection laws (known as directives) that apply to all of its member states. They include the 1976 Bathing Water Directive (updated 2006), which seeks to ensure the quality of the waters that people use for recreation. Most countries also have their own water pollution laws. In the United States, for example, there is the 1972 Clean Water Act and the 1974 Safe Drinking Water Act .

Most environmental experts agree that the best way to tackle pollution is through something called the polluter pays principle . This means that whoever causes pollution should have to pay to clean it up, one way or another. Polluter pays can operate in all kinds of ways. It could mean that tanker owners should have to take out insurance that covers the cost of oil spill cleanups, for example. It could also mean that shoppers should have to pay for their plastic grocery bags, as is now common in Ireland, to encourage recycling and minimize waste. Or it could mean that factories that use rivers must have their water inlet pipes downstream of their effluent outflow pipes, so if they cause pollution they themselves are the first people to suffer. Ultimately, the polluter pays principle is designed to deter people from polluting by making it less expensive for them to behave in an environmentally responsible way.

Our clean future

Life is ultimately about choices—and so is pollution. We can live with sewage-strewn beaches, dead rivers, and fish that are too poisonous to eat. Or we can work together to keep the environment clean so the plants, animals, and people who depend on it remain healthy. We can take individual action to help reduce water pollution, for example, by using environmentally friendly detergents , not pouring oil down drains, reducing pesticides, and so on. We can take community action too, by helping out on beach cleans or litter picks to keep our rivers and seas that little bit cleaner. And we can take action as countries and continents to pass laws that will make pollution harder and the world less polluted. Working together, we can make pollution less of a problem—and the world a better place.

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For younger readers.

• Earth Matters by Lynn Dicks et al. Dorling Kindersley, 2008: A more general guide to problems Earth faces, with each major biome explored separately. In case you're interested, I contributed the polar regions chapter. The book is mostly a simple read and probably suitable for 7–10 (and maybe 9–12).

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Text copyright © Chris Woodford 2006, 2022. All rights reserved. Full copyright notice and terms of use .

This article was originally written for the UK Rivers Network and first published on their website in April 2006. It is revised and updated every year.

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Water Pollution: Everything You Need to Know

Our rivers, reservoirs, lakes, and seas are drowning in chemicals, waste, plastic, and other pollutants. Here’s why―and what you can do to help.

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What is water pollution?

What are the causes of water pollution, categories of water pollution, what are the effects of water pollution, what can you do to prevent water pollution.

Water pollution occurs when harmful substances—often chemicals or microorganisms—contaminate a stream, river, lake, ocean, aquifer, or other body of water, degrading water quality and rendering it toxic to humans or the environment.

This widespread problem of water pollution is jeopardizing our health. Unsafe water kills more people each year than war and all other forms of violence combined. Meanwhile, our drinkable water sources are finite: Less than 1 percent of the earth’s freshwater is actually accessible to us. Without action, the challenges will only increase by 2050, when global demand for freshwater is expected to be one-third greater than it is now.

Water is uniquely vulnerable to pollution. Known as a “universal solvent,” water is able to dissolve more substances than any other liquid on earth. It’s the reason we have Kool-Aid and brilliant blue waterfalls. It’s also why water is so easily polluted. Toxic substances from farms, towns, and factories readily dissolve into and mix with it, causing water pollution.

Here are some of the major sources of water pollution worldwide:

Agricultural

Toxic green algae in Copco Reservoir, northern California

Aurora Photos/Alamy

Not only is the agricultural sector the biggest consumer of global freshwater resources, with farming and livestock production using about 70 percent of the earth’s surface water supplies , but it’s also a serious water polluter. Around the world, agriculture is the leading cause of water degradation. In the United States, agricultural pollution is the top source of contamination in rivers and streams, the second-biggest source in wetlands, and the third main source in lakes. It’s also a major contributor of contamination to estuaries and groundwater. Every time it rains, fertilizers, pesticides, and animal waste from farms and livestock operations wash nutrients and pathogens—such bacteria and viruses—into our waterways. Nutrient pollution , caused by excess nitrogen and phosphorus in water or air, is the number-one threat to water quality worldwide and can cause algal blooms , a toxic soup of blue-green algae that can be harmful to people and wildlife.

Sewage and wastewater

Used water is wastewater. It comes from our sinks, showers, and toilets (think sewage) and from commercial, industrial, and agricultural activities (think metals, solvents, and toxic sludge). The term also includes stormwater runoff , which occurs when rainfall carries road salts, oil, grease, chemicals, and debris from impermeable surfaces into our waterways

More than 80 percent of the world’s wastewater flows back into the environment without being treated or reused, according to the United Nations; in some least-developed countries, the figure tops 95 percent. In the United States, wastewater treatment facilities process about 34 billion gallons of wastewater per day . These facilities reduce the amount of pollutants such as pathogens, phosphorus, and nitrogen in sewage, as well as heavy metals and toxic chemicals in industrial waste, before discharging the treated waters back into waterways. That’s when all goes well. But according to EPA estimates, our nation’s aging and easily overwhelmed sewage treatment systems also release more than 850 billion gallons of untreated wastewater each year.

Oil pollution

Big spills may dominate headlines, but consumers account for the vast majority of oil pollution in our seas, including oil and gasoline that drips from millions of cars and trucks every day. Moreover, nearly half of the estimated 1 million tons of oil that makes its way into marine environments each year comes not from tanker spills but from land-based sources such as factories, farms, and cities. At sea, tanker spills account for about 10 percent of the oil in waters around the world, while regular operations of the shipping industry—through both legal and illegal discharges—contribute about one-third. Oil is also naturally released from under the ocean floor through fractures known as seeps.

Radioactive substances

Radioactive waste is any pollution that emits radiation beyond what is naturally released by the environment. It’s generated by uranium mining, nuclear power plants, and the production and testing of military weapons, as well as by universities and hospitals that use radioactive materials for research and medicine. Radioactive waste can persist in the environment for thousands of years, making disposal a major challenge. Consider the decommissioned Hanford nuclear weapons production site in Washington, where the cleanup of 56 million gallons of radioactive waste is expected to cost more than $100 billion and last through 2060. Accidentally released or improperly disposed of contaminants threaten groundwater, surface water, and marine resources.

To address pollution and protect water we need to understand where the pollution is coming from (point source or nonpoint source) and the type of water body its impacting (groundwater, surface water, or ocean water).

Where is the pollution coming from?

Point source pollution.

When contamination originates from a single source, it’s called point source pollution. Examples include wastewater (also called effluent) discharged legally or illegally by a manufacturer, oil refinery, or wastewater treatment facility, as well as contamination from leaking septic systems, chemical and oil spills, and illegal dumping. The EPA regulates point source pollution by establishing limits on what can be discharged by a facility directly into a body of water. While point source pollution originates from a specific place, it can affect miles of waterways and ocean.

Nonpoint source

Nonpoint source pollution is contamination derived from diffuse sources. These may include agricultural or stormwater runoff or debris blown into waterways from land. Nonpoint source pollution is the leading cause of water pollution in U.S. waters, but it’s difficult to regulate, since there’s no single, identifiable culprit.

Transboundary

It goes without saying that water pollution can’t be contained by a line on a map. Transboundary pollution is the result of contaminated water from one country spilling into the waters of another. Contamination can result from a disaster—like an oil spill—or the slow, downriver creep of industrial, agricultural, or municipal discharge.

What type of water is being impacted?

Groundwater pollution.

When rain falls and seeps deep into the earth, filling the cracks, crevices, and porous spaces of an aquifer (basically an underground storehouse of water), it becomes groundwater—one of our least visible but most important natural resources. Nearly 40 percent of Americans rely on groundwater, pumped to the earth’s surface, for drinking water. For some folks in rural areas, it’s their only freshwater source. Groundwater gets polluted when contaminants—from pesticides and fertilizers to waste leached from landfills and septic systems—make their way into an aquifer, rendering it unsafe for human use. Ridding groundwater of contaminants can be difficult to impossible, as well as costly. Once polluted, an aquifer may be unusable for decades, or even thousands of years. Groundwater can also spread contamination far from the original polluting source as it seeps into streams, lakes, and oceans.

Surface water pollution

Covering about 70 percent of the earth, surface water is what fills our oceans, lakes, rivers, and all those other blue bits on the world map. Surface water from freshwater sources (that is, from sources other than the ocean) accounts for more than 60 percent of the water delivered to American homes. But a significant pool of that water is in peril. According to the most recent surveys on national water quality from the U.S. Environmental Protection Agency, nearly half of our rivers and streams and more than one-third of our lakes are polluted and unfit for swimming, fishing, and drinking. Nutrient pollution, which includes nitrates and phosphates, is the leading type of contamination in these freshwater sources. While plants and animals need these nutrients to grow, they have become a major pollutant due to farm waste and fertilizer runoff. Municipal and industrial waste discharges contribute their fair share of toxins as well. There’s also all the random junk that industry and individuals dump directly into waterways.

Ocean water pollution

Eighty percent of ocean pollution (also called marine pollution) originates on land—whether along the coast or far inland. Contaminants such as chemicals, nutrients, and heavy metals are carried from farms, factories, and cities by streams and rivers into our bays and estuaries; from there they travel out to sea. Meanwhile, marine debris— particularly plastic —is blown in by the wind or washed in via storm drains and sewers. Our seas are also sometimes spoiled by oil spills and leaks—big and small—and are consistently soaking up carbon pollution from the air. The ocean absorbs as much as a quarter of man-made carbon emissions .

On human health

To put it bluntly: Water pollution kills. In fact, it caused 1.8 million deaths in 2015, according to a study published in The Lancet . Contaminated water can also make you ill. Every year, unsafe water sickens about 1 billion people. And low-income communities are disproportionately at risk because their homes are often closest to the most polluting industries.

Waterborne pathogens, in the form of disease-causing bacteria and viruses from human and animal waste, are a major cause of illness from contaminated drinking water . Diseases spread by unsafe water include cholera, giardia, and typhoid. Even in wealthy nations, accidental or illegal releases from sewage treatment facilities, as well as runoff from farms and urban areas, contribute harmful pathogens to waterways. Thousands of people across the United States are sickened every year by Legionnaires’ disease (a severe form of pneumonia contracted from water sources like cooling towers and piped water), with cases cropping up from California’s Disneyland to Manhattan’s Upper East Side.

A woman using bottled water to wash her three-week-old son at their home in Flint, Michigan

Todd McInturf/The Detroit News/AP

Meanwhile, the plight of residents in Flint, Michigan —where cost-cutting measures and aging water infrastructure created a lead contamination crisis—offers a stark look at how dangerous chemical and other industrial pollutants in our water can be. The problem goes far beyond Flint and involves much more than lead, as a wide range of chemical pollutants—from heavy metals such as arsenic and mercury to pesticides and nitrate fertilizers —are getting into our water supplies. Once they’re ingested, these toxins can cause a host of health issues, from cancer to hormone disruption to altered brain function. Children and pregnant women are particularly at risk.

Even swimming can pose a risk. Every year, 3.5 million Americans contract health issues such as skin rashes, pinkeye, respiratory infections, and hepatitis from sewage-laden coastal waters, according to EPA estimates.

On the environment

In order to thrive, healthy ecosystems rely on a complex web of animals, plants, bacteria, and fungi—all of which interact, directly or indirectly, with each other. Harm to any of these organisms can create a chain effect, imperiling entire aquatic environments.

When water pollution causes an algal bloom in a lake or marine environment, the proliferation of newly introduced nutrients stimulates plant and algae growth, which in turn reduces oxygen levels in the water. This dearth of oxygen, known as eutrophication , suffocates plants and animals and can create “dead zones,” where waters are essentially devoid of life. In certain cases, these harmful algal blooms can also produce neurotoxins that affect wildlife, from whales to sea turtles.

Chemicals and heavy metals from industrial and municipal wastewater contaminate waterways as well. These contaminants are toxic to aquatic life—most often reducing an organism’s life span and ability to reproduce—and make their way up the food chain as predator eats prey. That’s how tuna and other big fish accumulate high quantities of toxins, such as mercury.

Marine ecosystems are also threatened by marine debris , which can strangle, suffocate, and starve animals. Much of this solid debris, such as plastic bags and soda cans, gets swept into sewers and storm drains and eventually out to sea, turning our oceans into trash soup and sometimes consolidating to form floating garbage patches. Discarded fishing gear and other types of debris are responsible for harming more than 200 different species of marine life.

Meanwhile, ocean acidification is making it tougher for shellfish and coral to survive. Though they absorb about a quarter of the carbon pollution created each year by burning fossil fuels, oceans are becoming more acidic. This process makes it harder for shellfish and other species to build shells and may impact the nervous systems of sharks, clownfish, and other marine life.

With your actions

We’re all accountable to some degree for today’s water pollution problem. Fortunately, there are some simple ways you can prevent water contamination or at least limit your contribution to it:

• Learn about the unique qualities of water where you live . Where does your water come from? Is the wastewater from your home treated? Where does stormwater flow to? Is your area in a drought? Start building a picture of the situation so you can discover where your actions will have the most impact—and see if your neighbors would be interested in joining in!
• Reduce your plastic consumption and reuse or recycle plastic when you can.
• Properly dispose of chemical cleaners, oils, and nonbiodegradable items to keep them from going down the drain.
• Maintain your car so it doesn’t leak oil, antifreeze, or coolant.
• If you have a yard, consider landscaping that reduces runoff and avoid applying pesticides and herbicides .
• Don’t flush your old medications! Dispose of them in the trash to prevent them from entering local waterways.
• Be mindful of anything you pour into storm sewers, since that waste often won’t be treated before being released into local waterways. If you notice a storm sewer blocked by litter, clean it up to keep that trash out of the water. (You’ll also help prevent troublesome street floods in a heavy storm.)
• If you have a pup, be sure to pick up its poop .

With your voice

One of the most effective ways to stand up for our waters is to speak out in support of the Clean Water Act, which has helped hold polluters accountable for five decades—despite attempts by destructive industries to gut its authority. But we also need regulations that keep pace with modern-day challenges, including microplastics, PFAS , pharmaceuticals, and other contaminants our wastewater treatment plants weren’t built to handle, not to mention polluted water that’s dumped untreated.

Tell the federal government, the U.S. Army Corps of Engineers, and your local elected officials that you support water protections and investments in infrastructure, like wastewater treatment, lead-pipe removal programs, and stormwater-abating green infrastructure. Also, learn how you and those around you can get involved in the policymaking process . Our public waterways serve every one of us. We should all have a say in how they’re protected.

This story was originally published on May 14, 2018, and has been updated with new information and links.

This NRDC.org story is available for online republication by news media outlets or nonprofits under these conditions: The writer(s) must be credited with a byline; you must note prominently that the story was originally published by NRDC.org and link to the original; the story cannot be edited (beyond simple things such as grammar); you can’t resell the story in any form or grant republishing rights to other outlets; you can’t republish our material wholesale or automatically—you need to select stories individually; you can’t republish the photos or graphics on our site without specific permission; you should drop us a note to let us know when you’ve used one of our stories.

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• Biology Article
• Water Pollution Control

Water Pollution And Its Control

Water is one of the most vital natural resources on earth and has been around for a long time. In fact, the same water which we drink has been around in one form or the other since the time of the dinosaurs.

The earth has more than two-thirds of its surface covered with water. This translates to just over 1 octillion litres (1,260,000,000,000,000,000,000 litres) of water distributed in the oceans, rivers, lakes and streams.

That is a lot of water, however, less than 0.3% is accessible for human consumption. As commercialization and industrialization have progressed, that number continues to dwindle down. Furthermore, inefficient and outdated practices, lack of awareness and a plethora of other circumstances have led to water pollution.

Also Read: How Can We Conserve Water?

• Water pollution
• Modern Epidemic

Minamata Incident

• Ganges River

What is Water Pollution?

Water pollution can be defined as the contamination of water bodies. Water pollution is caused when water bodies such as rivers, lakes, oceans, groundwater and aquifers get contaminated with industrial and agricultural effluents.

When water gets polluted, it adversely affects all lifeforms that directly or indirectly depend on this source. The effects of water contamination can be felt for years to come.

Also Refer:  Types of Pollution

Sources Of Water Pollution

The key causative of water pollution in India are:

• Urbanization.
• Deforestation.
• Industrial effluents.
• Social and Religious Practices.
• Use of Detergents and Fertilizers.
• Agricultural run-offs- Use of insecticides and pesticides.

Water Pollution – A Modern Epidemic

One of the primary causes of water pollution is the contamination of water bodies by toxic chemicals. As seen in the example mentioned above, the dumped plastic bottles, tins, water cans and other wastes pollute the water bodies. These result in water pollution, which harms not just humans, but the whole ecosystem. Toxins drained from these pollutants, travel up to the food chain and eventually affect humans. In most cases, the outcome is destructive to only the local population and species, but it can have an impact on a global scale too.

Nearly 6 billion kilograms of garbage is dumped every year in the oceans. Apart from industrial effluents and untreated sewage, other forms of unwanted materials are dumped into various water bodies. These can range from nuclear waste to oil spills – the latter of which can render vast areas uninhabitable.

Effects Of Water Pollution

The effect of water pollution depends upon the type of pollutants and their concentration. Also, the location of water bodies is an important factor to determine the levels of pollution.

• Water bodies in the vicinity of urban areas are extremely polluted. This is the result of dumping garbage and toxic chemicals by industrial and commercial establishments.
• Water pollution drastically affects aquatic life. It affects their metabolism, and behaviour, and causes illness and eventual death. Dioxin is a chemical that causes a lot of problems from reproduction to uncontrolled cell growth or cancer. This chemical is bioaccumulated in fish, chicken and meat. Chemicals such as this travel up the food chain before entering the human body.
• The effect of water pollution can have a huge impact on the food chain. It disrupts the food chain. Cadmium and lead are some toxic substances, these pollutants upon entering the food chain through animals (fish when consumed by animals, humans) can continue to disrupt at higher levels.
• Humans are affected by pollution and can contract diseases such as hepatitis through faecal matter in water sources. Poor drinking water treatment and unfit water can always cause an outbreak of infectious diseases such as cholera, etc.
• The ecosystem can be critically affected, modified and destructured because of water pollution.

The Minamata Incident marked one of the worst cases of water pollution

In 1932, a factory in Minamata City, Japan began dumping its industrial effluent – Methylmercury, into the surrounding bay and the sea. Methylmercury is incredibly toxic to humans and animals alike, causing a wide range of neurological disorders.

Its ill effects were not immediately noticeable. However, this all changed as methylmercury started to bioaccumulate inside shellfish and fish in Minamata Bay. These affected organisms were then caught and consumed by the local population. Soon, the ill effects of methylmercury were becoming apparent.

Initially, animals such as cats and dogs were affected by this. The city’s cats would often convulse and make strange noises before dying – hence, the term “dancing cat disease” was coined. Soon, the same symptoms were observed in people, though the cause was not apparent at the time.

Other affected people showed symptoms of acute mercury poisoning such as ataxia, muscle weakness, loss of motor coordination, damage to speech and hearing etc. In severe cases, paralysis occurred, which was followed by coma and death.  These diseases and deaths continued for almost 36 years before they could be officially acknowledged by the government and the organisation.

Since then, various control measures for water pollution have been adopted by the government of Japan to curb such environmental disasters in the future.

Pollution of the Ganges

Some rivers, lakes, and groundwater are rendered unfit for usage. In India, the River Ganges is the sixth most polluted river in the world. This is unsurprising as hundreds of industries nearby release their effluents into the river. Furthermore, religious activities such as burials and cremations near the shore contribute to pollution. Apart from the ecological implications, this river poses a serious health risks as it can cause diseases like typhoid and cholera.

Pollution of the Ganges is also driving some of the distinct fauna to extinction. The Ganges River shark is a critically endangered species that belong to the order Carcharhiniformes. The Ganges River dolphin is another  endangered species of dolphin that is found in the tributaries of the Ganges and Brahmaputra rivers.

As per a survey, by the end of 2026, around 4 billion people will face a shortage of water. Presently, around 1.2 billion people worldwide do not have access to clean, potable water and proper sanitation. It is also projected that nearly 1000 children die every year in India due to water-related issues. Groundwater is an important source of water, but unfortunately, even that is susceptible to pollution. Hence, water pollution is quite an important social issue that needs to be addressed promptly.

Control Measures of Water Pollution

Water pollution, to a larger extent, can be controlled by a variety of methods. Rather than releasing sewage waste into water bodies, it is better to treat them before discharge. Practising this can reduce the initial toxicity and the remaining substances can be degraded and rendered harmless by the water body itself. If the secondary treatment of water has been carried out, then this can be reused in sanitary systems and agricultural fields.

A very special plant, the Water Hyacinth can absorb dissolved toxic chemicals such as cadmium and other such elements. Establishing these in regions prone to such kinds of pollutants will reduce the adverse effects to a large extent.

Some chemical methods that help in the control of water pollution are precipitation, the ion exchange process, reverse osmosis , and coagulation. As an individual, reusing, reducing, and recycling wherever possible will advance a long way in overcoming the effects of water pollution.

Further Reading:

Frequently Asked Questions

What is sewage treatment.

Wastewater treatment or sewage treatment generally refers to the process of cleaning or removing all pollutants, treating wastewater and making it safe and suitable for drinking before releasing it into the environment.

What are the main steps in sewage treatment?

There are four main stages of the wastewater treatment process, namely:

• Stage 1: Screening
• Stage 2: Primary treatment
• Stage 3: Secondary treatment
• Stage 4: Final treatment

What are the main causes of water pollution?

The main causes of water pollution are attributed to

• Industrial activities
• Urbanization
• Religious and social practices
• Agricultural runoff
• Accidents (such as oil spills, nuclear fallouts etc)

What are the effects of water pollution?

Water pollution can have disastrous consequences on the ecosystem. Furthermore, toxic chemicals can travel through the food chain and get into our bodies, causing diseases and death.

To learn more about water pollution, causes, effects, preventive measures and other important environmental concerns (such as eutrophication), visit us at BYJU’S Biology.

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102 Water Pollution Essay Topic Ideas & Examples

Water pollution essays are an excellent way to demonstrate your awareness of the topic and your position on the solutions to the issue. To help you ease the writing process, we prepared some tips, essay topics, and research questions about water pollution.

🌎 Air and Water pollution: Essay Writing Tips

🏆 best water pollution essay topics & examples, 📌 remarkable air and water pollution research topics, 👍 good research topics about water pollution, ❓ research questions about water pollution.

Water’s ready availability in many locations makes it an easy choice for a variety of purposes, from cleaning to manufacturing to nuclear reactor cooling. However, many companies will then dump water, now mixed with waste, back into rivers or lakes without adequate cleaning, leading to significant environmental pollution.

However, there are other types of harm, such as noise pollution, which are less obvious but also dangerous to sea life. It is critical that you understand what you should and should not do during your writing process.

The stance that big manufacturing industries are the sole culprits of the damage done to the world’s rivers and oceans is a popular one. However, do not neglect the effects of other water pollution essay topics such as microorganisms.

Microbes can spread dangerous illnesses, making them a danger for both water inhabitants and the people who then use that water. Furthermore, they can eat up oxygen if left unchecked, starving fish and other water organisms and eventually making them die out.

Such situations usually result from agricultural practices, which can lead to powerful nutrients entering the water and enabling algae and other microorganisms to grow excessively. An overly lively environment can be as harmful as one where everything is threatened.

With that said, industrial manufacturers deserve much of the attention and blame they receive from various communities. Construction of dedicated waste-cleaning facilities is usually possible, but companies avoid doing so because the process will increase their costs.

You should advocate for green practices, but be mindful of the potential impact of a significant price increase on the global economy. Also, be sure to mention more exotic pollution variations in your types of water pollution essay.

Provide examples of noise pollution or suspended matter pollution to expand on the topic of the complexity of the harm humanity causes to the ecosphere.

You should show your understanding that there are many causes, and we should work on addressing all of them, a notion you should repeat in your water pollution essay conclusions.

However, you should try to avoid being sidetracked too much and focus on the titles of pollution and its immediate causes.

If you stretch far enough, you may connect the matter to topics such as the status of a woman in Islam. However, doing so contributes little to nothing to your point and deviates from the topic of ecology into social and religious studies.

Leave the search for connections to dedicated researchers and concentrate on discussing the major causes that are known nowadays. By doing this, you will be able to create an excellent and powerful work that will demonstrate your understanding of the topic.

Here are some tips for your writing:

• Be sure to discuss the different types of pollution that is caused by the same source separately. Surface and groundwater pollution are different in their effects and deserve separate discussions.
• Focus on the issues and not on solutions, as an essay does not provide enough space to discuss the latter in detail.
• Be sure to discuss the effects of pollution on people and other land inhabitants as well as on water creatures.

Check IvyPanda to get more water pollution essay titles, paper ideas, and other useful samples!

• Air and Water Pollution in the Modern World The high number of vehicles in the city has greatly promoted air pollution in the area. Poor sewerage system, high pollution from industries and automobiles are among the major causes of air and water pollutions […]
• Water Pollution: Causes, Effects and Possible Solutions This is why clean water is required in all the places to make sure the people and all the living creatures in the planet live a good and healthy life.
• Water Pollution: Causes, Effects, and Prevention Farmers should be encouraged to embrace this kind of farming which ensures that the manure used is biodegradable and do not end up accumulating in the water bodies once they are washed off by floods.
• Water Pollution in the Philippines: Metropolitan Manila Area In this brief economic analysis of water pollution in Metro Manila, it is proposed to look at the industrial use of waters and the household use to understand the impact that the population growth and […]
• Coca-Cola India and Water Pollution Issues The first difficulty that the representatives of the Coca-Cola Company happened to face due to their campaign in the territory of India was caused by the concerns of the local government.
• Cashion Water Quality: Spatial Distribution of Water Pollution Incidents This essay discusses the quality of water as per the report of 2021 obtained from the municipality, the quality issue and the source of pollution, and how the pollution impacts human health and the environment […]
• Water Pollution: OIL Spills Aspects The effects of the oil spill on a species of ducks called the Harlequin ducks were formulated and the author attempted to trace out the immediate and residual effects of the oil on the birds.
• Importance of Mercury Water Pollution Problem Solutions The severity of the mercury contamination consequences depends on the age of the person exposed to the contamination, the way of contamination, the health condition, and many other factors.
• Water Pollution as a Crime Against the Environment In particular, water pollution is a widespread crime against the environment, even though it is a severe felony that can result in harm to many people and vast territories.
• Newark Water Crisis: Water Pollution Problem The main problem was rooted in the fact that lead levels in the drinking water were highly elevated, which is dangerous and detrimental to the population’s health.
• Water Pollution in a Community: Mitigation Plan Though for the fact that planet earth is abundant with water and almost two-thirds of the planet is made up of water still it is viewed that in future years, a shortage of water may […]
• Food Distribution and Water Pollution Therefore, food distribution is one of the central reasons for water pollution. According to Greenpeace, one of the ways to improve the ecology of the planet is by creating healthy food markets.
• Water Pollution and Associated Health Risks The results of plenty of studies indicate the existence of the relation between the contamination of water by hazardous chemicals and the development of respiratory and cardiovascular diseases, cancer, asthma, allergies, as well as reproductive […]
• Lake Erie Water Pollution There are worries among the members of the community that the lake could be facing another episode of high toxicity, and they have called for the authorities to investigate the main causes of the pollution […]
• Storm Water Pollution Prevention Plan All players need to be trained in significant areas of business so as they can handle them with care and beware of the potential they have in causing damage.
• Water Pollution in the US: Causes and Control Although water pollution can hardly be ceased entirely, the current rates of water pollution can be reduced by resorting to the sustainable principle of water use in both the industrial area and the realm of […]
• Water Pollution and Management in the UAE The groundwater in UAE meets the needs of 51% of users in terms of quantity mainly for irrigation. Surface water is the source of groundwater and plays a major role in groundwater renewal.
• Water Pollution and Its Challenges Water pollution refers to a situation where impurities find way into water bodies such as rivers, lakes, and ground water. This is a form of pollution where impurities enter water bodies through distinct sources such […]
• Water Pollution Sources, Effects and Control Unfortunately, not all the users of water are responsible to ensure that proper disposal or treatment of the used water is done before the water is returned to the water bodies.
• Water in Crisis: Public Health Concerns in Africa In the 21st century, the world faces a crisis of contaminated water, which is the result of industrialization and is a major problem in developing countries.
• Air and Water Pollution Thus, it is classified as a primary pollutant because it is the most common pollutants in the environment. In the environment, the impact of carbon monoxide is felt overtime, since it leads to respiratory problems.
• Causes of Water Pollution and the Present Environmental Solution Prolonged pollution of water has even caused some plants to grow in the water, which pose danger to the living entities that have their inhabitants in the water.
• Water Pollution & Diseases (Undeveloped Nations) Restriction on movement and access to the affected area affects trade and the loss of human life and deteriorated health is a major blow on the economy and on the quality of human life.
• Water and Water Pollution in Point of Economics’ View This research tries to explain the importance of water especially in an economist’s perspective by explaining the uses of water in various fields, pollution of water and the agents of pollution.
• Environmental Justice Issues Affecting African Americans: Water Pollution Water pollution in the 1960s occurred due to poor sewage systems in the urban and rural areas. Unlike in the 1960s, there are reduced cases of water pollution today.
• Water Pollution and Wind Energy Chemical pollution of water is one of the leading causes of death of aquatic life. It is thus evident that chemical pollution of water not only has negative effects on health, but it also substantially […]
• Air and Water Pollution in Los Angeles One of the major problems facing major cities and towns in the world is pollution; wastes from firms and households are the major causes of pollution.
• Water Pollution Causes and Climate Impacts The biggest percentage of sewage waste consists of water, treating the wastes for recycling would help in maintaining a constant supply of water.
• Water Pollution Origins and Ways of Resolving The evidence provided by environmental agencies indicates that industrial agriculture is one of the factors that significantly contribute to the deterioration of water quality.
• Mud Lick Creek Project – Fresh Water Pollution This potential source of pollutants poses significant risks to the quality of water at the creek in terms altering the temperature, pH, dissolved oxygen, and the turbidity of the water.
• Water Pollution in the Jamaican Society
• Water Pollution and Abstraction and Economic Instruments
• Water Pollution and Individual Effects of Water Pollution
• Understanding What Causes Water Pollution
• An Analysis of Water Pollution as a Global Plague That Affects the People, Animals and Plants
• Water Pollution Through Urban and Rural Land Use and Freshwater Allocation in New Zealand
• Water Pollution: Globalization, One of the Causes and Part of the Solution
• Voluntary Incentives for Reducing Agricultural Nonpoint Source Water Pollution
• The Impact of Water Pollution on Public Health in Flint, Michigan
• Understanding Water Pollution and Its Causes
• The Promises and Pitfalls of Devolution: Water Pollution Policies in the American States
• We Must Fight Against Water Pollution
• Transaction Costs and Agricultural Nonpoint-Source Water Pollution Control Policies
• Water Pollution and Drinking Water Quality
• Water Pollution: An Insight into the Greatest Environmental Risk
• US Water Pollution Regulation over the Past Half Century: Burning Waters to Crystal Springs
• Environmental Impact and Health Risks of Water Pollution to a Child
• Water Pollution Environment Effects Chemicals
• The Negative Effects of Water Pollution on Fish Numbers in America
• The Problem of Oil Spills and Water Pollution in Alaska
• Water Pollution in the United State: The Causes and Effects
• California Water Pollution Act Clean Laws
• The Need to Immediately Stop Water Pollution in the United States
• Water Pollution, Causes, Effects and Prevention
• The Water Pollution Prevention in Oceanic Areas
• Water Pollution and the Biggest Environmental Issues Today
• Fresh Water Pollution Assignment
• Water pollution in Southeast Asia and China
• Water Pollution Caused by Industrial Equipment
• The Impacts of Water Pollution on Economic Development in Sudan
• The Importance of Recycling to Prevent Water Pollution
• Water Pollution and Its Effects on The Environment
• The Sources, Environmental Impact, and Control of Water Pollution
• Water Quality and Contamination of Water Pollution
• Water Pollution and the World’s Worst Forms of Pollution
• The Problem of Water Pollution and the Solutions
• Comparing Contrast Legislative Approach Controlling Water Pollution Industrial
• An Analysis of the Water Pollution and it’s Effects on the Environment
• Water Pollution and The Natural Environment
• The Importance of Clean Drinking Water Pollution
• Water Pollution and Arsenic Pollution
• The Issue of Water Pollution in the Drinking Water in Brisbane
• What Are the Causes and Effects of Water Pollution?
• What Is the Effect of Water Pollution on Humanity?
• How Can Leaders Tackle with Water Pollution in China?
• What Is the Drinking Water Pollution Control Act?
• What Was the Social Water Pollution?
• How Non-Point Is Water Pollution Controlled in Agriculture?
• What Is Canada’s Water Pollution Dilemma?
• Water Pollution: Why Is There Trash in the Ocean?
• What Are the Problems Associated with Water Pollution?
• What Is the Connection Between Air and Water Pollution?
• How Water Pollution Effects Marine Life?
• What Are the Leading Factors of Water Pollution Around the World?
• Why Is Water Pollution an Important Issue Environmental Sciences?
• What Are the Factors That Causes Water Pollution and Its Effects on the World Today?
• What Are There Inorganic Chemicals Cause Water Pollution?
• How Does Drinking Water Pollution Impact the World Environmental Sciences?
• Is There a Connection Between Drinking Water Quality and Water Pollution?
• How to Deal with the Big Problem of Deforestation and Water Pollution in Brazil and the Colombian Amazon?
• Why Is China’s Water Pollution Challenge?
• What Is the Ground Water Pollution Assignment?
• How to Deal the Big Problem of Water Pollution in the World?
• How to Reduce Air and Water Pollution?
• What Is the Harmonizing Model with Transfer Tax on Water Pollution Across Regional Boundaries in China’s Lake Basin?
• Are the Causes and Effects of Water Pollution Determined in Lake Huron?
• Can Water Pollution Policy Be Efficient?
• What Are the Kinds of Water Pollution Environmental Sciences?
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• Chicago (A-D)
• Chicago (N-B)

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5.1: Physical Resources- Water, Pollution, and Minerals - Chapter Introduction

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• Page ID 12038

• Heriberto Cabezas
• Georgia College and State University via GALILEO Open Learning Materials

Introduction

Water, air, and food are the most important natural resources to people. Humans can live only a few minutes without oxygen, about a week without water, and about a month without food. Water also is essential for our oxygen and food supply. Plants, which require water to survive, provide oxygen through photosynthesis and form the base of our food supply. Plants grow in soil, which forms by weathering reactions between water and rock.

Water is the most essential compound for Earth’s life in general. Human babies are approximately 75% water and adults are 50–60% water. Our brain is about 85% water, blood and kidneys are 83% water, muscles are 76% water, and even bones are 22% water. We constantly lose water by perspiration; in temperate climates we should drink about 2 quarts of water per day and people in hot desert climates should drink up to 10 quarts of water per day. Loss of 15% of body-water usually causes death. Earth is truly the “Water Planet” (see Figure \(\PageIndex{1}\)). The abundance of water on Earth distinguishes us from other bodies in the solar system. About 70% of Earth's surface is covered by oceans and approximately half of Earth's surface is obscured by clouds at any time. There is a very large volume of water on our planet, about 1.4 billion cubic kilometers (km3) (330 million cubic miles) or about 53 billion gallons per person on Earth. All of Earth’s water could cover the United States to a depth of 145 km (90 mi). From a human perspective, the problem is that over 97% of it is seawater, which is too salty to drink or use for irrigation. The most commonly used water sources are rivers and lakes, which contain less than 0.01% of the world’s water!

One of our most important environmental goals is to provide a clean, sufficient, and sustainable water supply for the world. Fortunately, water is a renewable resource, and it is difficult to destroy. Evaporation and precipitation combine to replenish our fresh water supply constantly and quickly; however, water availability is complicated by its uneven distribution over the Earth. Arid climate and densely populated areas have combined in many parts of the world to create water shortages, which are projected to worsen significantly in the coming years. Human activities such as water overuse and water pollution have compounded the water crisis that exists today. Hundreds of millions of people lack access to safe drinking water, and billions of people lack access to improved sanitation as simple as a pit latrine. As a result, nearly two million people die every year from diarrheal diseases and 90% of those deaths occur among children under the age of 5. Most of these are easily prevented deaths.

Although few minerals are absolutely essential for human life, the things that define modern society require a wide range of them: iron ore for steel, phosphate minerals for fertilizer, limestone rock for concrete, rare earth elements for night-vision goggles and phosphors in computer monitors, and lithium minerals for batteries in our laptops, cell phones, and electric cars. As global population grows and emerging large economies expand, we will face a crisis in the supply of many important minerals because they are nonrenewable, which is to say we consume them far more quickly than nature creates them. As we consume minerals from larger and lower grade mineral deposits there will be greater environmental impacts from mineral mining and processing. The impending mineral crisis may be more challenging to address than the water crisis.

This chapter introduces basic principles in water supply, water pollution, and mineral resources. The emphasis, however, is on environmental issues and sustainable solutions for each problem.

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7.14: Water Pollution

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• Page ID 189484

• Heriberto Cabezas
• Georgia College and State University via GALILEO Open Learning Materials

Learning Objectives

After reading this module, students should be able to

• understand the major kinds of water pollutants and how they degrade water quality
• understand how and why the lack of safe drinking water in some parts of the world is a major problem
• know what sewage treatment does and why it is important
• know why it is more difficult to remediate groundwater pollution than surface water pollution
• understand how we can work toward solving the crisis involving water pollution

The Water Pollution Crisis

The Module 7.3 described one aspect of the global water crisis, the water shortages that afflict many arid and densely populated areas. The global water crisis also involves water pollution, because to be useful for drinking and irrigation, water must not be polluted beyond certain thresholds. According to the World Health Organization, in 2008 approximately 880 million people in the world (or 13% of world population) did not have access to improved (safe) drinking water (World Health Statistics, 2010) (See Figure \(\PageIndex{1}\)). At the same time, about 2.6 billion people (or 40% of world population) lived without improved sanitation (see Figure \(\PageIndex{2}\)), which is defined as having access to a public sewage system, septic tank, or even a simple pit latrine. Each year approximately 1.7 million people die from diarrheal diseases associated with unsafe drinking water, inadequate sanitation, and poor hygiene, e.g., hand washing with soap. Almost all of these deaths are in developing countries, and around 90% of them occur among children under the age of 5 (see Figure \(\PageIndex{3}\)). Compounding the water crisis is the issue of social justice; poor people more commonly lack clean water and sanitation than wealthy people in similar areas. Globally, improving water, sanitation, and hygiene could prevent up to 9% of all disease and 6% of all deaths. In addition to the global waterborne disease crisis, chemical pollution from agriculture, industry, cities, and mining threatens global water quality. Some chemical pollutants have serious and well-known health effects; however, many others have poorly known long-term health effects. In the U.S. currently more than 40,000 water bodies fit the definition of “impaired” set by EPA (See Figure \(\PageIndex{4}\)), which means they could neither support a healthy ecosystem nor meet water quality standards. In Gallup public polls conducted over the past decade Americans consistently put water pollution and water supply as the top environmental concerns over issues such as air pollution, deforestation, species extinction, and global warming.

Water Chemistry Overview

Compared to other molecules of similar molecular weight, water (H 2 O) has unique physical properties including high values for melting and boiling point, surface tension (water’s cohesion, or “stickiness”), and capacity to dissolve soluble minerals, i.e., act as a solvent. These properties are related to its asymmetrical structure and polar nature , which means it is electrically neutral overall but it has a net positive charge on the side with the two hydrogen atoms and a net negative charge on the oxygen side (see Figure \(\PageIndex{5}\)). This separation of the electrical charge within a water molecule results in hydrogen bonds with other water molecules, mineral surfaces (hydrogen bonding produces the water films on minerals in the unsaturated zone of the subsurface), and dissolved ions (atoms with a negative or positive charge). Many minerals and pollutants dissolve readily in water because water forms hydration shells (spheres of loosely coordinated, oriented water molecules) around ions.

Any natural water contains dissolved chemicals; some of these are important human nutrients, while others can be harmful to human health. The abundance of a water pollutant is commonly given in very small concentration units such as parts per million (ppm) or even parts per billion (ppb). An arsenic concentration of 1 ppm means 1 part of arsenic per million parts of water. This is equivalent to one drop of arsenic in 50 liters of water. To give you a different perspective on appreciating small concentration units, converting 1 ppm to length units is 1 cm (0.4 in) in 10 km (6 miles) and converting 1 ppm to time units is 30 seconds in a year. Total dissolved solids (TDS) represent the total amount of dissolved material in water. Average TDS (salinity) values for rainwater, river water, and seawater are about 4 ppm, 120 ppm, and 35,000 ppm. As discussed in Module 5.2, the most important processes that affect the salinity of natural waters are evaporation, which distills nearly pure water and leaves the dissolved ions in the original water, and chemical weathering, which involves mineral dissolution that adds dissolved ions to water. Fresh water is commonly defined as containing less than either 1,000 or 500 ppm TDS, but the US Environmental Protection Agency (EPA) recommends that drinking water not exceed 500 ppm TDS or else it will have an unpleasant salty taste.

Water Pollution Overview

Water pollution is the contamination of water by an excess amount of a substance that can cause harm to human beings and the ecosystem. The level of water pollution depends on the abundance of the pollutant, the ecological impact of the pollutant, and the use of the water. Pollutants are derived from biological, chemical, or physical processes. Although natural processes such as volcanic eruptions or evaporation sometimes can cause water pollution, most pollution is derived from human, land-based activities (see Figure \(\PageIndex{6}\)). Water pollutants can move through different water reservoirs, as the water carrying them progresses through stages of the water cycle (see Figure \(\PageIndex{7}\)). Water residence time (the average time that a water molecule spends in a water reservoir) is very important to pollution problems because it affects pollution potential. Water in rivers has a relatively short residence time, so pollution usually is there only briefly. Of course, pollution in rivers may simply move to another reservoir, such as the ocean, where it can cause further problems. Groundwater is typically characterized by slow flow and longer residence time, which can make groundwater pollution particularly problematic. Finally, pollution residence time can be much greater than the water residence time because a pollutant may be taken up for a long time within the ecosystem or absorbed onto sediment.

Pollutants enter water supplies from point sources, which are readily identifiable and relatively small locations, or nonpoint sources, which are large and more diffuse areas. Point sources of pollution include animal “factory” farms that raise a large number and high density of livestock such as cows, pigs, and chickens (see Figure \(\PageIndex{8}\)) and discharge pipes from a factories or sewage treatment plants. Combined sewer systems that have a single set of underground pipes to collect both sewage and storm water runoff from streets for wastewater treatment can be major point sources of pollutants. During heavy rain, storm water runoff may exceed sewer capacity, causing it to back up and spilling untreated sewage into surface waters (see Figure \(\PageIndex{9}\)). Nonpoint sources of pollution include agricultural fields, cities, and abandoned mines. Rainfall runs over the land and through the ground, picking up pollutants such as herbicides, pesticides, and fertilizer from agricultural fields and lawns; oil, antifreeze, car detergent, animal waste, and road salt from urban areas; and acid and toxic elements from abandoned mines. Then, this pollution is carried into surface water bodies and groundwater. Nonpoint source pollution, which is the leading cause of water pollution in the U.S., is usually much more difficult and expensive to control than point source pollution because of its low concentration, multiple sources, and much greater volume of water.

Types of Water Pollutants

Oxyden-demanding waste is an extremely important pollutant to ecosystems. Most surface water in contact with the atmosphere has a small amount of dissolved oxygen, which is needed by aquatic organisms for cellular respiration. Bacteria decompose dead organic matter (chemically represented in a simplified way as CH 2 O) and remove dissolved oxygen (O 2 ) according to the following reaction:

\[ CH2O+O2→CO2+H2O \nonumber\]

Too much decaying organic matter in water is a pollutant because it removes oxygen from water, which can kill fish, shellfish, and aquatic insects. The amount of oxygen used by aerobic (in the presence of oxygen) bacterial decomposition of organic matter is called biochemical oxygen demand (BOD). The major source of dead organic matter in most natural waters is sewage; grass and leaves are smaller sources. An unpolluted water body with respect to oxygen is a turbulent river that flows through a natural forest. Turbulence continually brings water in contact with the atmosphere where the O 2 content is restored. The dissolved oxygen content in such a river ranges from 10 to 14 ppm O 2 , BOD is low, and clean-water fish, e.g., bass, trout, and perch dominate. A polluted water body with respect to oxygen is a stagnant deep lake in an urban setting with a combined sewer system. This system favors a high input of dead organic carbon from sewage overflows and limited chance for water circulation and contact with the atmosphere. In such a lake, the dissolved O 2 content is ≤5 ppm O 2 , BOD is high, and low O 2 -tolerant fish, e.g., carp and catfish dominate.

Excessive plant nutrients, particularly nitrogen (N) and phosphorous (P), are pollutants closely related to oxygen-demanding waste. Aquatic plants require about 15 nutrients for growth, most of which are plentiful in water. N and P are called limiting nutrients , because they usually are present in water at low concentrations and therefore restrict the total amount of plant growth. This explains why N and P are major ingredients in most fertilizer. High concentrations of N and P from human sources (mostly agricultural and urban runoff including fertilizer, sewage, and P-based detergent) can cause cultural eutrophication, which involves the rapid growth of aquatic plants, particularly algae, called an algal bloom . Thick mats of floating and rooted green or sometimes red algae (see Figure \(\PageIndex{10}\)) create water pollution, damage the ecosystem by clogging fish gills and blocking sunlight, and damage lake aesthetics by making recreation difficult and creating an eyesore. A small percentage of algal species produce toxins that can kill fish, mammals, and birds, and may cause human illness; explosive growths of these algae are called harmful algal blooms (see Figure \(\PageIndex{11}\)). When the prolific algal layer dies, it becomes oxygen-demanding waste, which can create very low O 2 water (<~2 ppm O 2 ), called hypoxia or dead zone because it causes death to organisms that are unable to leave that environment. An estimated 50% of lakes in North America, Europe, and Asia are negatively impacted by cultural eutrophication. In addition, the size and number of marine hypoxic zones have grown dramatically over the past 50 years (see Figure \(\PageIndex{12}\)), including a very large dead zone located offshore Louisiana in the Gulf of Mexico. Cultural eutrophication and hypoxia are difficult to combat, because they are caused primarily by nonpoint source pollution, which is difficult to regulate, and N and P, which are difficult to remove from wastewater.

Pathogens are disease-causing microorganisms, e.g., viruses, bacteria, parasitic worms, and protozoa, which cause a variety of intestinal diseases such as dysentery, typhoid fever, hepatitis, and cholera. Pathogens are the major cause of the water pollution crisis discussed at the beginning of this section. Unfortunately nearly a billion people around the world are exposed to waterborne pathogen pollution daily and around 1.5 million children mainly in underdeveloped countries die every year of waterborne diseases from pathogens (see Figure \(\PageIndex{3}\)). Pathogens enter water primarily from human and animal fecal waste due to inadequate sewage treatment. In many underdeveloped countries, sewage is discharged into local waters either untreated or after only rudimentary treatment. In developed countries untreated sewage discharge can occur from overflows of combined sewer systems, poorly managed livestock factory farms, and leaky or broken sewage collection systems (see Figure \(\PageIndex{14}\)). Water with pathogens can be remediated by adding chlorine or ozone, by boiling, or by treating the sewage in the first place.

Oil spills are another kind of organic pollution. Oil spills can result from supertanker accidents such as the Exxon Valdez in 1989, which spilled 10 million gallons of oil into the rich ecosystem of offshore south Alaska and killed massive numbers of animals. The largest marine oil spill was the Deepwater Horizon disaster, which began with a natural gas explosion (see Figure \(\PageIndex{14}\) ) at an oil well 65 km offshore of Louisiana and flowed for 3 months in 2010, releasing an estimated 200 million gallons of oil. The worst oil spill ever occurred during the Persian Gulf war of 1991, when Iraq deliberately dumped approximately 200 million gallons of oil in offshore Kuwait and set more than 700 oil well fires that released enormous clouds of smoke and acid rain for over nine months. During an oil spill on water, oil floats to the surface because it is less dense than water, and the lightest hydrocarbons evaporate, decreasing the size of the spill but polluting the air. Then, bacteria begin to decompose the remaining oil, in a process that can take many years. After several months only about 15% of the original volume may remain, but it is in thick asphalt lumps, a form that is particularly harmful to birds, fish, and shellfish. Cleanup operations can include skimmer ships that vacuum oil from the water surface (effective only for small spills), controlled burning (works only in early stages before the light, ignitable part evaporates but also pollutes the air), dispersants (detergents that break up oil to accelerate its decomposition, but some dispersants may be toxic to the ecosystem), and bioremediation (adding microorganisms that specialize in quickly decomposing oil, but this can disrupt the natural ecosystem).

Toxic chemicals involve many different kinds and sources, primarily from industry and mining. General kinds of toxic chemicals include hazardous chemicals , which are a wide variety of synthetic organic and inorganic chemicals such as acids, bases, cyanide, and a class of compounds called persistent organic pollutants that includes DDT (pesticide), dioxin (herbicide by-product), and PCBs (polychlorinated biphenyls, which were used as a liquid insulator in electric transformers). Persistent organic pollutants are long-lived in the environment, accumulate through the food chain (bioaccumulation), and can be toxic. Another category of toxic chemicals includes radioactive materials such as cesium, iodine, uranium, and radon gas, which can result in long-term exposure to radioactivity if it gets into the body. A final group of toxic chemicals is heavy metals such as lead, mercury, arsenic, cadmium, and chromium, which can accumulate through the food chain. Heavy metals are commonly produced by industry and at metallic ore mines. Arsenic and mercury are discussed in more detail below. The US EPA regulates 83 contaminants in drinking water to ensure a safe public water supply. Similarly, at the international level the World Health Organization has drinking water standards for a variety of contaminants.

Arsenic (As) has been famous as an agent of death for many centuries. In large doses arsenic causes cancer and can be fatal. Only recently have scientists recognized that health problems can be caused by drinking small arsenic concentrations in water over a long time. It attacks the central nervous system and can damage the respiratory system, bladder, lungs, liver, and kidneys. It enters the water supply naturally from weathering of As-rich minerals and from human activities such as coal burning and smelting of metallic ores. The worst case of arsenic poisoning occurred in the densely populated impoverished country of Bangladesh, which had experienced 100,000s of deaths from diarrhea and cholera each year from drinking surface water contaminated with pathogens due to improper sewage treatment. In the 1970s the United Nations provided aid for millions of shallow water wells, which resulted in a dramatic drop in pathogenic diseases. Unfortunately, many of the wells produced water naturally rich in arsenic. Tragically, there are an estimated 77 million people (about half of the population) who inadvertently may have been exposed to toxic levels of arsenic in Bangladesh as a result. The World Health Organization has called it the largest mass poisoning of a population in history.

Mercury (Hg) is used in a variety of electrical products, such as dry cell batteries, fluorescent light bulbs, and switches, as well as in the manufacture of paint, paper, vinyl chloride, and fungicides. In the methylmercury form (CH 3 Hg + ) it is highly toxic; ≥ 1 ppb of methylmercury represents water contaminated with mercury. Mercury concentrates in the food chain, especially in fish, in a process caused biomagnification (see Sidebar Biomagnification ). It acts on the central nervous system and can cause loss of sight, feeling, and hearing as well as nervousness, shakiness, and death. Like arsenic, mercury enters the water supply naturally from weathering of Hg-rich minerals and from human activities such as coal burning and metal processing. A famous mercury poisoning case in Minamata, Japan involved methylmercury-rich industrial discharge that caused high Hg levels in fish. People in the local fishing villages ate fish up to three times per day for over 30 years, which resulted in over 2,000 deaths. During that time the responsible company and national government did little to mitigate, help alleviate, or even acknowledge the problem.

Biomagnification

Biomagnification represents the processes in an ecosystem that cause greater concentrations of a chemical, such as methylmercury, in organisms higher up the food chain. Mercury and methylmercury are present in only very small concentrations in seawater; however, at the base of the food chain algae absorb methylmercury. Then, small fish eat the algae, large fish and other organisms higher in the food chain eat the small fish, and so on. Fish and other aquatic organisms absorb methylmercury rapidly but eliminate it slowly from the body. Therefore, each step up the food chain increases the concentration from the step below (see Figure \(\PageIndex{15}\)). Largemouth bass can concentrate methylmercury up to 10 million times over the water concentration and fish-eating birds can concentrate it even higher. Other chemicals that exhibit biomagnification are DDT, PCBs, and arsenic.

Other water pollutants include sediment and heat. Muddy water is bad for drinking but even worse for underwater plants that need sunlight for photosynthesis. Much of the sediment in water bodies is derived from the erosion of soil, so it also represents a loss of agricultural productivity. Thermal pollution involves the release of heated waters from power plants and industry to surface water, causing a drop in the dissolved O 2 content, which can stress fish.

Hard water contains abundant calcium and magnesium, which reduces its ability to develop soapsuds and enhances scale (calcium and magnesium carbonate minerals) formation on hot water equipment. Water softeners remove calcium and magnesium, which allows the water to lather easily and resist scale formation. Hard water develops naturally from the dissolution of calcium and magnesium carbonate minerals in soil; it does not have negative health effects in people.

Groundwater pollution can occur from underground sources and all of the pollution sources that contaminate surface waters. Common sources of groundwater pollution are leaking underground storage tanks for fuel, septic tanks, agricultural activity, and landfills. Common groundwater pollutants include nitrate, pesticides, volatile organic compounds, and petroleum products. Polluted groundwater can be a more serious problem than polluted surface water because the pollution in groundwater may go undetected for a long time because usually it moves very slowly. As a result, the pollution in groundwater may create a contaminant plume, a large body of flowing polluted groundwater (see Figure \(\PageIndex{15}\)), making cleanup very costly. By the time groundwater contamination is detected, the entity responsible for the pollution may be bankrupt or nonexistent. Another troublesome feature of groundwater pollution is that small amounts of certain pollutants, e.g., petroleum products and organic solvents, can contaminate large areas. In Denver, Colorado 80 liters of several organic solvents contaminated 4.5 trillion liters of groundwater and produced a 5 km long contaminant plume. Most groundwater contamination occurs in shallow, unconfined aquifers located near the contamination source. Confined aquifers are less susceptible to pollution from the surface because of protection by the confining layer. A major threat to groundwater quality is from underground fuel storage tanks. Fuel tanks commonly are stored underground at gas stations to reduce explosion hazards. Before 1988 in the U.S. these storage tanks could be made of metal, which can corrode, leak, and quickly contaminate local groundwater. Now, leak detectors are required and the metal storage tanks are supposed to be protected from corrosion or replaced with fiberglass tanks. Currently there are around 600,000 underground fuel storage tanks in the U.S. and over 30% still do not comply with EPA regulations regarding either release prevention or leak detection.

Sustainable Solutions to the Water Pollution Crisis?

Resolution of the global water pollution crisis described at the beginning of this section requires multiple approaches to improve the quality of our fresh water and move towards sustainability. The most deadly form of water pollution, pathogenic microorganisms that cause waterborne diseases, kills almost 2 million people in underdeveloped countries every year. The best strategy for addressing this problem is proper sewage (wastewater) treatment. Untreated sewage is not only a major cause of pathogenic diseases, but also a major source of other pollutants, including oxygen-demanding waste, plant nutrients (N and P), and toxic heavy metals. Wastewater treatment is done at a sewage treatment plant in urban areas and through a septic tank system in rural areas.

The main purpose of a sewage treatment plant is to remove organic matter (oxygen-demanding waste) and kill bacteria; special methods also can be used to remove plant nutrients and other pollutants. The numerous processing steps at a conventional sewage treatment plant (see Figure \(\PageIndex{17}\)) include pretreatment (screening and removal of sand and gravel), primary treatment (settling or floatation to remove organic solids, fat, and grease), secondary treatment (aerobic bacterial decomposition of organic solids), tertiary treatment (bacterial decomposition of nutrients and filtration), disinfection (treatment with chlorine, ozone, ultraviolet light, or bleach), and either discharge to surface waters (usually a local river) or reuse for some other purpose, such as irrigation, habitat preservation, and artificial groundwater recharge. The concentrated organic solid produced during primary and secondarytreatment is called sludge, which is treated in a variety of ways including landfill disposal, incineration, use as fertilizer, and anaerobic bacterial decomposition, which is done in the absence of oxygen. Anaerobic decomposition of sludge produces methane gas, which can be used as an energy source. To reduce water pollution problems, separate sewer systems (where street runoff goes to rivers and only wastewater goes to a wastewater treatment plant) are much better than combined sewer systems, which can overflow and release untreated sewage into surface waters during heavy rain. Some cities such as Chicago, Illinois have constructed large underground caverns and also use abandoned rock quarries to hold storm sewer overflow. After the rain stops, the stored water goes to the sewage treatment plant for processing.

A septic tank system is an individual sewage treatment system for homes in rural and even some urban settings. The basic components of a septic tank system (see Figure \(\PageIndex{18}\)) include a sewer line from the house, a septic tank (a large container where sludge settles to the bottom and microorganisms decompose the organic solids anaerobically), and the drain field (network of perforated pipes where the clarified water seeps into the soil and is further purified by bacteria). Water pollution problems occur if the septic tank malfunctions, which usually occurs when a system is established in the wrong type of soil or maintained poorly.

For many developing countries, financial aid is necessary to build adequate sewage treatment facilities; however, the World Health Organization estimates an estimated cost savings of between $3 and $34 for every $1 invested in clean water delivery and sanitation ( Water for Life, 2005 ). The cost savings are from health care savings, gains in work and school productivity, and deaths prevented. Simple and inexpensive techniques for treating water at home include chlorination, filters, and solar disinfection. Another alternative is to use constructed wetlands technology (marshes built to treat contaminated water), which is simpler and cheaper than a conventional sewage treatment plant.

Bottled water is not a sustainable solution to the water crisis, despite exponential growth in popularity in the U.S. and the world. Bottled water is not necessarily any safer than the U.S. public water supply, it costs on average about 700 times more than U.S. tap water, and every year it uses approximately 200 billion plastic and glass bottles that have a relatively low rate of recycling. Compared to tap water, it uses much more energy, mainly in bottle manufacturing and long-distance transportation. If you don’t like the taste of your tap water, then please use a water filter instead of bottled water!

Additional sustainable solutions to the water pollution crisis include legislation to eliminate or greatly reduce point sources of water pollution. In the U.S., the Clean Water Act of 1972 and later amendments led to major improvements in water quality (see Sidebar Clean Water Act). Nonpoint sources of water pollution, e.g., agricultural runoff and urban runoff (see Figure \(\PageIndex{19}\)), are much harder to regulate because of their widespread, diffuse nature. There are many construction and agricultural practices that reduce polluted runoff including no-till farming and sediment traps. Artificial aeration or mechanical mixing can remediate lakes with oxygen depletion. Specific things that we can do to reduce urban runoff include the following: keep soil, leaves, and grass clippings off driveways, sidewalks, and streets; don't pour used motor oil, antifreeze, paints, pesticides, or any household hazardous chemical down the storm sewer or drain; recycle used motor oil; use hazardous waste disposal programs offered by the community; compost your organic waste; don't use fertilizers and herbicides on your lawn; and flush pet waste down the toilet.

Clean Water Act

During the early 1900s rapid industrialization in the U.S. resulted in widespread water pollution due to free discharge of waste into surface waters. The Cuyahoga River in northeast Ohio caught fire numerous times (see Figure \(\PageIndex{20}\)), including a famous fire in 1969 that caught the nation’s attention. In 1972 Congress passed one of the most important environmental laws in U.S. history, the Federal Water Pollution Control Act, which is more commonly called the Clean Water Act. The purpose of the Clean Water Act and later amendments is to maintain and restore water quality, or in simpler terms to make our water swimmable and fishable. It became illegal to dump pollution into surface water unless there was formal permission and U.S. water quality improved significantly as a result. More progress is needed because currently the EPA considers over 40,000 U.S. water bodies as impaired, most commonly due to pathogens, metals, plant nutrients, and oxygen depletion. Another concern is protecting groundwater quality, which is not yet addressed sufficiently by federal law.

Sometimes slow flow through a soil can naturally purify groundwater because some pollutants, such as P, pesticides, and heavy metals, chemically bind with surfaces of soil clays and iron oxides. Other pollutants are not retained by soil particles: These include N, road salt, gasoline fuel, the herbicide atrazine, tetrachloroethylene (a carcinogenic cleaning solvent used in dry cleaning), and vinyl chloride. In other cases, slow groundwater flow can allow bacteria to decompose dead organic matter and certain pesticides. There are many other ways to remediate polluted groundwater. Sometimes the best solution is to stop the pollution source and allow natural cleanup. Specific treatment methods depend on the geology, hydrology, and pollutant because some light contaminants flow on top of groundwater, others dissolve and flow with groundwater, and dense contaminants can sink below groundwater. A common cleanup method called pump and treat involves pumping out the contaminated groundwater and treating it by oxidation, filtration, or biological methods. Sometimes soil must be excavated and sent to a landfill. In-situ treatment methods include adding chemicals to immobilize heavy metals, creating a permeable reaction zone with metallic iron that can destroy organic solvents, or using bioremediation by adding oxygen or nutrients to stimulate growth of microorganisms.

Review Questions

• What are the major kinds of water pollutants and how do they degrade water quality?
• How would you rank the water pollution problems described in this chapter? Why?
• Why is untreated sewage such an important water pollutant to remediate?
• What should society learn from the case history of Love Canal?
• Why are people facing a crisis involving water pollution and how can we solve it?

Water for Life: Making it Happen (2005) World Health Organization and UNICEF. Retrieved from http://www.who.int/water_sanitation_health/waterforlife.pdf

World Health Statistics (2010) World Health Organization. Retrieved from http://www.who.int/whosis/whostat/EN_WHS10_Full.pdf

• Water and Water Pollution

We already know that Water is the most important resource on the planet . It is the essence of all life on earth. And yet if you ever see a river or lake around your city, it would be evident to you that we are facing a very serious problem of Water pollution. Let us educate ourselves about water and water pollution.

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As shown in the image above, the water cycle is a natural process that is continuous in nature. It is the pattern in which the water from oceans, seas, lakes etc gets evaporated and turns to vapour. After which it goes through the process of condensation, and finally precipitation when it falls back to earth as rain or snow.

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What is Water Pollution?

Water pollution is the contamination of water bodies (like oceans, seas, lakes, rivers, aquifers, and groundwater ) usually caused due to human activities. Water pollution is any change in the physical, chemical or biological properties of water that will have a detrimental consequence of any living organism .

Drinking water, also called Potable Water, is the water that is considered safe enough for human and animal consumption. This is water that is generally used for drinking, cooking, washing, crop irrigation , etc. These days chemicals, bacteria , and other pollutants are even affecting our drinking water .

Learn more about Air and Air Pollution here .

Sources of Water Pollution

Some of the most commonly occurring water pollutants are

• Domestic Waste
• Industrial effluents
• Insecticides and pesticides
• Detergents and Fertilizers

Some of the water pollution that is caused is by Direct Sources , such as factories, waste management facilities. refineries etc, that directly release waste and harmful by-products into the nearest water source without treating them. Indirect sources include pollutants that enter the water bodies via groundwater or soil or via the atmosphere as acid rain.

Effects of Pollution of Water

• Diseases: In humans, drinking or consuming polluted water in any way has many disastrous effects on our health. It causes typhoid, cholera, hepatitis and various other diseases.
• Destruction of Ecosystems: Ecosystems are extremely dynamic and respond to even small changes in the environment. Water pollution can cause an entire ecosystem to collapse if left unchecked.
• Eutrophication: Chemicals in a water body, encourage the growth of algae . These algae form a layer on top of the pond or lake. Bacteria feed on this algae and this decreases the amount of oxygen in the water body, severely affecting the aquatic life there.
• Effects the food chain: Disruption in food chains happens when toxins and pollutants in the water are consumed by aquatic animals (fish, shellfish etc) which are then consumed by humans.

The best way to prevent large-scale water pollution is to try and reduce its harmful effects. There are various small changes we can make to protect ourselves from a scary future where water is scarce.

• Save Water: Conserving water is our first aim. Water wastage is a major problem globally and we are only now waking up to the issue. Simply small changes you can make domestically will make a huge difference.
• Better treatment of sewage: So treating waste products before disposing of it in a water body helps reduce water pollution on a large scale. Agriculture or other industries can reuse this wastewater by reducing its toxic contents.
• Use environmentally friendly products: By using soluble products that do not go on to become pollutants, we can reduce the amount of water pollution caused by a household.

Solved Example for You

Q: What is thermal water pollution?

• Colour of the water is changed
• A change in Water pressure
• Change in temperature of water
• pH of water changes

Solution: The correct answer is “c”. Thermal pollution is the rise and fall in the temperature of a natural body of water caused by human influence. And Thermal pollution, unlike chemical pollution, results in a change in the physical properties of water.

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Natural Resources

• Mineral Riches in the Soil
• Biogeochemical Cycles

2 responses to “Air and Air Pollution”

is it possible to get the authors name and the date this was published? I need this for a paper.

Hi Josh, it was published on 19th January 2018 by Preksha Thakkar from Toppr.

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Essay on Water Pollution

Here we have shared the Essay on Water Pollution in detail so you can use it in your exam or assignment of 150, 250, 400, 500, or 1000 words.

You can use this Essay on Water Pollution in any assignment or project whether you are in school (class 10th or 12th), college, or preparing for answer writing in competitive exams. 

Topics covered in this article.

Essay on Water Pollution in 150-250 words

Essay on water pollution in 300-400 words, essay on water pollution in 500-1000 words.

Water pollution is a pressing environmental issue that poses a significant threat to ecosystems and human health. It occurs when harmful substances, such as chemicals, industrial waste, or sewage, contaminate water bodies, including rivers, lakes, oceans, and groundwater sources.

Water pollution has devastating consequences on aquatic life. Toxic pollutants can disrupt the balance of ecosystems, leading to the decline of fish and other marine species. Additionally, contaminated water can spread diseases to animals and humans who depend on these water sources for drinking, irrigation, and recreation.

Industrial activities, improper waste disposal, agricultural runoff, and urbanization contribute to water pollution. Efforts to reduce water pollution include stricter regulations on waste disposal, the promotion of sustainable agricultural practices, and the development of advanced wastewater treatment technologies.

Awareness and individual responsibility are crucial in combating water pollution. Simple actions like properly disposing of waste, conserving water, and avoiding the use of harmful chemicals can make a significant difference. Education and advocacy are essential to raising public awareness about the importance of protecting water resources and implementing sustainable practices.

In conclusion, water pollution is a grave environmental issue that threatens aquatic ecosystems and human well-being. It is a global challenge that requires collective action and responsible behavior. By implementing effective regulations, adopting sustainable practices, and promoting awareness, we can safeguard our water resources and ensure a healthier and more sustainable future for all.

Title: Water Pollution – A Growing Threat to Ecosystems and Human Well-being

Introduction :

Water pollution is a grave environmental issue that arises from the contamination of water bodies by harmful substances. It poses a significant threat to aquatic ecosystems and human health. This essay explores the causes and consequences of water pollution, as well as the measures required to address and prevent it.

Causes of Water Pollution

Water pollution can be attributed to various human activities and natural factors. Industrial discharge, improper waste disposal, agricultural runoff, oil spills, sewage, and chemical pollutants are among the leading causes. Rapid urbanization, population growth, and inadequate infrastructure for waste management contribute to the problem. Additionally, natural phenomena like sedimentation and erosion can exacerbate water pollution.

Consequences of Water Pollution

Water pollution has far-reaching ecological and human health implications. Contaminated water disrupts aquatic ecosystems, leading to the decline of fish and other marine species. It affects biodiversity, disrupts food chains, and damages habitats. Moreover, polluted water sources pose significant health risks to humans. Consuming or coming into contact with contaminated water can lead to waterborne diseases, gastrointestinal issues, skin problems, and even long-term health impacts.

Prevention and Remediation

Addressing water pollution requires a multi-faceted approach. Stricter regulations and enforcement regarding industrial discharge and waste management are essential. Promoting sustainable agricultural practices, such as reducing the use of chemical fertilizers and implementing proper irrigation techniques, can minimize agricultural runoff. Developing and implementing advanced wastewater treatment technologies is crucial to ensure that domestic and industrial effluents are properly treated before being discharged into water bodies.

Individual and Collective Responsibility:

Preventing water pollution is a shared responsibility. Individuals can contribute by practicing responsible waste disposal, conserving water, and avoiding the use of harmful chemicals. Public awareness campaigns and education programs play a vital role in promoting responsible behavior and fostering a culture of environmental stewardship.

Conclusion :

Water pollution is a critical environmental issue that jeopardizes the health of ecosystems and humans. It demands collective action and responsible behavior. By addressing the root causes of water pollution, implementing effective regulations, and promoting individual and collective responsibility, we can safeguard water resources and ensure a sustainable future for generations to come.

Title: Water Pollution – A Looming Crisis Threatening Ecosystems and Human Well-being

Water pollution is a pressing environmental issue that poses a significant threat to ecosystems, biodiversity, and human health. It occurs when harmful substances contaminate water bodies, making them unfit for their intended uses. This essay delves into the causes, consequences, and potential solutions to water pollution, emphasizing the urgent need for collective action to address this global crisis.

Water pollution arises from various sources, both human-induced and natural. Human activities play a significant role in polluting water bodies. Industrial discharge, untreated sewage, agricultural runoff, oil spills, mining activities, and improper waste disposal are among the leading causes. Industrial wastewater often contains heavy metals, toxic chemicals, and organic pollutants, which can have devastating effects on aquatic ecosystems and human health. Agricultural runoff, laden with pesticides, fertilizers, and animal waste, contaminates water bodies and contributes to eutrophication, depleting oxygen levels and harming aquatic life.

The consequences of water pollution are far-reaching and encompass ecological, economic, and health impacts. Aquatic ecosystems bear the brunt of pollution, with devastating consequences for biodiversity and food chains. Pollutants disrupt aquatic habitats, decrease water quality, and lead to the decline of fish and other marine species. This ecological imbalance has ripple effects throughout the ecosystem, affecting the entire food web.

Water pollution also has severe implications for human health. Contaminated water sources pose significant risks, as they can transmit waterborne diseases, including cholera, typhoid, dysentery, and hepatitis. Communities that rely on polluted water for drinking, cooking, and bathing are particularly vulnerable. Prolonged exposure to polluted water can lead to various health issues, such as gastrointestinal problems, skin irritations, respiratory illnesses, and even long-term health effects like cancer.

Furthermore, water pollution has economic ramifications. Polluted water bodies reduce the availability of clean water for agriculture, industry, and domestic use. This leads to increased costs for water treatment, agricultural productivity losses, and economic disruptions in sectors that rely heavily on water resources, such as fisheries and tourism.

Solutions and Mitigation Strategies

Addressing water pollution requires comprehensive strategies and collaborative efforts. Governments, industries, communities, and individuals all have a role to play in mitigating pollution and safeguarding water resources.

a. Regulatory Measures

B. wastewater treatment, c. sustainable agriculture, d. waste management, e. education and awareness.

Effective regulations and enforcement mechanisms are essential to control and prevent water pollution. Governments should establish stringent standards for industrial effluents and enforce penalties for non-compliance. Laws should be enacted to ensure proper waste disposal and treatment practices. Additionally, zoning regulations can help prevent pollution by restricting industrial activities near sensitive water bodies.

Investing in advanced wastewater treatment infrastructure is crucial. Industries should implement appropriate treatment technologies to remove pollutants from their effluents before discharge. Municipalities must prioritize the treatment of domestic sewage to prevent contamination of water bodies. Developing countries, in particular, need support and resources to build and upgrade their wastewater treatment facilities.

Adopting sustainable agricultural practices can significantly reduce pollution from agricultural activities. Encouraging the use of organic farming methods, integrated pest management, and precision irrigation can minimize the reliance on harmful pesticides and fertilizers. Proper manure management and implementing buffer zones along water bodies can also mitigate nutrient runoff and protect water quality.

Improper waste disposal is a major contributor to water pollution. Implementing comprehensive waste management systems that include recycling, proper landfill management, and promotion of waste reduction strategies is crucial. Communities should have access to adequate waste collection services, and educational campaigns can raise awareness about the importance of responsible waste disposal.

Public education and awareness programs play a vital role in addressing water pollution. Promoting water conservation practices, encouraging responsible behavior, and highlighting the link between water pollution and human health can empower individuals to take action. Educational campaigns should target schools, communities, and industries to foster a culture of environmental stewardship.

Water pollution is a critical global issue that poses severe threats to ecosystems, biodiversity, and human well-being. It demands collective action and sustainable practices to safeguard water resources. Through stringent regulations, advanced wastewater treatment, sustainable agriculture, proper waste management, and education, we can mitigate water pollution and preserve this vital resource for future generations. By recognizing the urgency of this crisis and working collaboratively, we can ensure a healthier, cleaner, and more sustainable water future.

FREE K-12 standards-aligned STEM

curriculum for educators everywhere!

Find more at TeachEngineering.org .

• TeachEngineering
• Introduction to Water Chemistry

Lesson Introduction to Water Chemistry

Grade Level: 8 (7-9)

Time Required: 45 minutes

Lesson Dependency: None

Subject Areas: Chemistry, Physical Science, Science and Technology

NGSS Performance Expectations:

• Print lesson and its associated curriculum

Curriculum in this Unit Units serve as guides to a particular content or subject area. Nested under units are lessons (in purple) and hands-on activities (in blue). Note that not all lessons and activities will exist under a unit, and instead may exist as "standalone" curriculum.

• Thinking Green!
• Chromatography Lab
• Water Remediation Lab
• Red Cabbage Chemistry
• Density Column Lab - Part 1
• Density Column Lab - Part 2

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Engineering connection, learning objectives, worksheets and attachments, more curriculum like this, introduction/motivation, associated activities, vocabulary/definitions, additional multimedia support, user comments & tips.

The environmental engineering topics concerning water quality are highly relevant issues facing engineers, as well as communities and ecosystems at large. Example issues include the impact of global warming on the Earth's fresh water supply, the sources of groundwater contamination, and the innovative technologies employed by environmental engineers to address groundwater contamination.

After this lesson, students should be able to:

• Explain the importance of maintaining fresh, unpolluted drinking water supplies.
• Describe sources and consequences of poor water quality.
• List and describe new and existing water remediation technologies.

Educational Standards Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards. All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN) , a project of D2L (www.achievementstandards.org). In the ASN, standards are hierarchically structured: first by source; e.g. , by state; within source by type; e.g. , science or mathematics; within type by subtype, then by grade, etc .

Ngss: next generation science standards - science, international technology and engineering educators association - technology.

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State Standards

Missouri - science.

(In advance, make copies of the Introduction to Water Chemistry Worksheet and prepare to show the class the attached 17-slide Introduction to Water Chemistry Presentation , a PowerPoint file.)

Water, or H 2 O, is a small yet complex molecule that can be linked to almost every organism and chemical process. Humans rely so heavily on water that it is essential that we maintain clean drinking water supplies. This presentation focuses on the importance of water, sources of water contamination, and ways environmental engineers help to clean contaminated water.

(Continue on to present students with the information found in the Lesson Background section.)

Lesson Background and Concepts for Teachers

(Hand out copies of the worksheet for students to complete during the PowerPoint presentation. The slides are "animated," so clicking the mouse or space bar brings up the next item.)

Slide 1: Introduction to Water Chemistry

Slide 2: Why Water? Clean water is essential to our lives! Review the interesting facts about water and U.S. water consumption. These are just some of the reasons why it is so important to maintain high water quality.

Slide 3: The Water Cycle: Thoroughly describe the water cycle if students are unfamiliar with it. Otherwise, just highlight the main processes, such as condensation, precipitation and evaporation. Water stored in oceans is extremely salty, making it undrinkable. When water evaporates and returns as rain or snow, it is clean because salts and other minerals are left behind during the process. A great amount of freshwater storage is in mountain ice caps. Global climate change (mentioned in the Introduction to Environmental Engineering lesson) is melting ice caps on mountaintops and at the poles, removing the Earth's last source of stored freshwater.

Slide 4: Key Terms: To continue the discussion on water quality, review with students the definitions for: contamination, purification and remediation.

Slide 5: How do we purify water? Larger-scale, industrial methods to clean large amounts of water include reverse osmosis, ultra-filtration and electro-deionization. Smaller-scale, household methods include filters and boiling. Often, these processes are combined in order to effectively remove contaminants. Details are covered in the next slides.

Slide 6: Reverse Osmosis: Reverse osmosis is one type of filtration method. The two left images show examples of reverse osmosis membrane layers. The two right images show example set-ups for the reverse osmosis process for large scale water purification. The system is composed of a series of membranes and pumps. What do the membranes do? (Answer: They separate things or keep things out.) As the water passes through the membrane, the larger contaminants are left behind, leaving cleaned water. (As necessary, show students two online diagrams on how reverse osmosis works; see the URLs in the Additional Multimedia Support section.) Note that government regulatory agencies permit some chemicals to be added to water, such as chlorine (for disinfection) and fluorine.

Slide 7: Filters: Sand filtration is a natural filtration process that occurs in groundwater systems, and is often used when treating natural water resources, such as rivers, to make them clean enough for drinking water. Water pitchers with activated carbon filters are used for small-scale water purification at home. Students can explore the effectivness of such filters with the hands-on associated activity Water Remediation Lab .

Slide 8: Activated Carbon: Activated carbon is an important component of many home water purification systems. Looking at the top left image, poultry manure pellets (top pile) are converted through a manufacturing process into activated carbon pellets (left pile), and then ground into either a granular (center pile) or powdered (right pile) form. A magnified image shows the tiny pores through which water flows through the activated carbon and out the filter. If desired, show students online illustrations of how activated carbon pores provide increased surface area for gas and chemical pollutants to adsorb; see the URLs in the Additional Multimedia Support section.) A system of water filtration includes many layers of materials through which water flows. In this one, the activated carbon layer is the fourth level from the bottom, and other layers include pebbles, palm fiber, alum, gravel, chlorine and sand. Refer to the associated activity Chromatography Lab to increase students' awareness of possible invisible pollutants in drinking water sources by investigating the chromatography process using the ink from markers.

Slide 9: Boiling Water: Boiling water used to be the only way to purify water, but now is considered the "last resort" purification method. Boiling water destroys most bacteria and viruses, but can still leave behind harmful chemicals.

Slide 10: Contamination Sources: Common human-created water contamination sources include leaking sewage, leaking underground fuel storage tanks, agricultural chemical runoff, landfills and dumps, and industrial waste. As world population has increased over the years, the magnitude of freshwater contamination has generally increased as well. Increased population corresponds to increased demand for products and services, and many of which involve chemicals. Furthermore, new chemicals are often developed as part of technology advancement. Despite efforts to prevent chemical releases to the environment, the presence of chemical in the environment is inevitable, even with environmental regulations enacted in many countries. Details on contaminant sources are covered in the next slides.

Overall, the top water pollution sources are: pesticides; fertilizers/nutrient pollution; oil, gasoline and additives; mining; sediment, chemical and industrial processes; plastic; personal care products, household cleaning products and pharmaceuticals; sewage; air pollution (chemicals deposited out of air into water), carbon dioxide (absorbed into water, making it more acidic); heat (a water pollutant); noise pollution (human ships and sonars affect animal communication, navigation and hunting).

Slide 11: Sewage Spills: In the U.S., 850 billion gallons of raw sewage are dumped into rivers, lakes and oceans by leaking and overflowing sewer/storm systems. In developing countries, it is common for sewage to be discharged directly into bodies of water without treatment. Refer to the associated activity Red Cabbage Chemistry for students to act as environmental engineers by exploring pH and measurment techniques.

Slide 12: Underground Storage Tanks: Have you ever seen large trucks pumping gasoline underground at gas stations? In the U.S., most gasoline is stored underground in large storage tanks. To help gasoline burn better, we used to add chemicals that if ingested could cause birth defects and other illnesses in humans. The left image shows a newly installed underground storage tank. The right image shows an old, corroded, leaking tank that was polluting groundwater.

Slide 13: Pesticides and Herbicides: Pesticides and herbicides contain harmful chemicals with the purpose to kill insects and weeds. When it rains, the sprayed pesticides and herbicides on crops (and lawns!) are transported by runoff into groundwater and nearby bodies of water. If ingested in large amounts, these chemicals can cause birth defects in humans. Related to this, fertilizers also contain chemicals that enter groundwater through soil runoff. Excess nutrient levels overstimulate the growth of aquatic plants and algae and disturb organism balance.

Slide 14: Industrial Waste Spills: Hazardous liquid waste might include solvents, heavy metals and radioactive materials. In the U.S., 34 billion liters per year of hazardous waste is injected deep underground with the intent that it will be kept away from our water supplies for a long period of time; however, some of these pollutants have been detected in underground water supplies in many states. In developing countries, most wastewater from industrial plant chemical processes is added to sewage wastewater, which more often than not, is discharged directly into rivers and streams without treatment. Environmental engineers have developed various water remediation techniques to improve water quality at contaminated sites (see next three slides).

Slide 15: Pump-and-Treat: Several technologies have been developed to help treat groundwater contamination sources. In a pump-and-treat system, injection wells are placed near the start and end of an underground water source. Contaminated water is pumped up and sent to a treatment facility; once cleaned, it is pumped back underground. This process works well initially, but becomes less efficient over several years.

Slide 16: Permeable Reactive Barrier: Using permeable reactive barriers is another common method for purifying water at an underground water contamination source. The process is similar to reverse osmosis. The barrier is essentially a large membrane, made of some reactive material, such as activated carbon or iron (oxidation reaction), that lets clean water pass through and traps contaminants. Problems with this method include: it takes a long time for all the contaminated water to pass through, the reactive material must be replaced once the active sites for adsorption are saturated, and its use is limited to contamination sites at shallow depths.

Slide 17: Nanoparticle Injection: This newer water remediation technique involves nanotechnology. Have you ever seen an old, rusted piece of metal? Rust is produced when water reacts at the iron surface. The same chemical reaction happens when iron nanoparticles make contact with contaminated groundwater. (Nanoparticles are so tiny we cannot see them. A billion nanometers are in one meter.) Instead of rust forming at the surface of the iron nanoparticles, the reaction breaks down contaminants into smaller, less harmful species. Researchers are still figuring out issues with this method, such as how to stabilize the nanoparticles so they can travel underground easily.

Watch this activity on YouTube

• Water Remediation Lab - Students collect data on how well activated carbon filters purify chlorine-contaminated water. Groups prepare chlorinated water samples, pass the samples through Brita® water filters, and measure chlorine concentrations over time. After gathering and graphing data, students evaluate the effectiveness of this engineer-designed household water remediation method.

adsorption: The binding of atoms, ions or molecules from a gas, liquid or dissolved substance to a surface, such as on the surfaces of pores of activated carbon.

contamination: The presence of a minor component in another chemical or mixture.

groundwater: The water under the Earth's surface, consisting largely of surface water that has seeped down and is stored within saturated soil and rock. (In this usage, saturated means full of water.) The source of water in springs and wells.

purification: To make something pure or to cleanse.

remediation: To correct something that has gone bad or defective; to provide a remedy.

Worksheet: Have students complete the Introduction to Water Chemistry Worksheet by writing definitions and answering questions while the teacher presents the PowerPoint presentation. Collect, review and grade the worksheets to assess student engagement and comprehension of the material.

Show students two online diagrams that illustrate the concept of osmosis through semi-permeable membranes and why these membranes are able to filter out impurities in water, under the Osmotic Balance and Free Water Passing Through Membrane Pores sections at the at the Equistat (Isle of Man) Limited website: http://www.equistat.co.uk/science/understanding_fluid_comp.php.

Show students online illustrations of how activated carbon pores provide increased surface area for chemical pollutants to adsorb at: http://innofresh.wordpress.com/2011/01/04/carbon-vs-activated-carbon-for-use-as-an-odor-absorber/ and http://www.capitalcarbon.in/process.html.

Students are presented with examples of the types of problems that environmental engineers solve, specifically focusing on air and land quality issues.

Students are introduced to the fundamentals of environmental engineering as well as the global air, land and water quality concerns facing today's environmental engineers. Specifically, they focus on groundwater contamination and remediation, including sources of contamination, adverse health effect...

Jeantheau, Mark. A List of Water Pollution Causes. Published September 6, 2005. Grinning Planet: Saving the Planet One Joke at a Time . Issue No. 141. Accessed October 24, 2012. (Comprehensive list and description of the top point and nonpoint water pollution sources.) http://www.grinningplanet.com/2005/09-06/water-pollution-causes-article.htm

Reddy, Krishna R. Physical and Chemical Groundwater Remediation Technologies. Chapter 12 in Overexploitation and Contamination of Shared Groundwater Resources: Management, (Bio)Technological, and Political Approaches to Avoid Conflict . Editor: Christophe J.G. Darnault. Netherlands: Springer, 200; pp 257. http://link.springer.com/content/pdf/10.1007%2F978-1-4020-6985-7_12

The Water Cycle – Water Science for Schools. Last updated October 15, 2012. U.S. Geological Survey, U.S. Department of the Interior. Accessed October 24, 2012. (Water cycle diagram and information on the distribution of the Earth's water) http://ga.water.usgs.gov/edu/watercycle.html

What You Should Know about Water. Read, Learn, and Know about Water, AllAboutWater.org. Accessed October 24, 2012. http://allaboutwater.org/

Contributors

Supporting program, acknowledgements.

This curriculum was developed with support from National Science Foundation GK-12 grant number DGE 0538541. However, these contents do not necessarily represent the policies of the NSF, and you should not assume endorsement by the federal government.

Last modified: June 16, 2019

Environmental Pollution [Environmental Studies Notes BCOM/BA/BSC 2nd SEM CBCS Pattern]

Unit 5: environmental pollution (8 lectures), environmental studies notes for ba, b.com and bsc cbcs pattern.

• Environmental pollution: types, causes, effects and controls; Air, water, soil and noise pollution

• Nuclear hazards and human health risks

• Solid waste management: Control measures of urban and industrial waste.

• Pollution case studies – Bharalu river, Deepor Beel, Kolong river

**************

Table of Contents

Soil Pollution

Land is an important component of environment because soil is vital for the substances of life on earth. An inch of soil takes about 500 to 1000 years to be build. It is estimated that the total surface area of earth is 3,15,14,640 square km out of which only about one third is land surface. It is a resource for which there is no substitute. So, it becomes necessary to protect soil from pollutants.

Soil pollution can be more dangerous than other types of pollution. Soil pollution is defined as the presence of toxic chemicals (pollutants or contaminants) in soil, in high enough concentrations to pose risk to human health and ecosystem. Soil pollution is the adverse alternation in the properties of the soil due to dumping of solid and semi-solid waste from agriculture, industry and urban areas. It also results because of washing down of pollutants by rain and faulty sanitation in the soil.

Sources of Soil Pollution

a) Agrochemicals: The application of inorganic fertilisers to crop lands and the use of toxic insecticides, pesticides, fungicides etc. for controlling diseases have an adverse impact of soil.

b) Industrial waste: The rapid growth of industries has resulted in the release of a lot of industrial waste on the land surface. The quality of those wastes depends on the types of raw materials and chemicals used in the industries. The toxic chemicals are absorbed by the green plants along with the nutrients and enter into the food chain and finally reaching the human being causing health hazards.

c) Domestic Garbage: Plastics are mainly used as packing materials which are normally thrown away as garbage. This garbage is pile up at public places which creates disposal problem.

d) Petroleum wastes: Contamination of soil by petroleum products is a major cause of soil pollution in several countries in the world.

e) Electric Waste: Electronic waste like cell phones, computers, gadgets, printers, radio, camera, video games, scanners, DVDs, Land phones etc. are non-biodegradable waste which is generally dumped in soil.

Measures to Control Soil Pollution

Since soil is vital for life, these should be protected from pollution. Some important measures to control soil pollution are:

a) Agro-chemicals should be used with caution in the field. Organic manure should be used instead of agro-chemicals.

b) Use of bio-fertilizers should be encouraged instead of chemical fertilizers.

c) Industrial effluents should be properly treated before discharging them on the soil. The effluents released should be subjected to proper treatment before their release into land mass.

d) The garbage produced should be dumped in closed chamber.

e) Adequate latrine facility should be provided in rural and urban areas.

f) Public awareness programmes should be implemented to educate people on health hazards due to soil pollution. Prevention of erosion and silting.

g) People should be trained regarding proper sanitary practices.

h) Application of pesticides should be controlled.

i) Bioremediation can be adopted for degradation of toxic chemicals present in soil.

Effects of Soil Pollution

a) Industrial wastes consist of a variety of chemicals which are extremely toxic. Chemical like acids, alkalis, pesticides, heavy metals etc. affect soil fertility and ultimately affect human health.

b) Nitrogen and phosphorus from the fertilizers in soil reach nearby water bodies with agricultural run-off and cause eutrophication.

c) Excess use of chemical fertilizers may result in reducing the ability of plants to fix nitrogen.

d) Pollutants in soil cause alteration in soil structure, causing death of many soil organisms which can affect the food chain.

e) Decline in the microorganisms found in the soil creating additional problems of soil erosion.

f) Contamination of underground and surface drinking water.

Water Pollution

Water is undoubtedly the most precious natural resource that exists on our planet. It is essential for the survival of any form of life. Lakes, rivers, seas and groundwater are the main source of water. Water pollution  is the  pollution  of bodies of  water , such as lakes, rivers, seas, the oceans, as well as groundwater. It occurs when  pollutants reach these bodies of  water , without treatment. Waste from homes, factories and other buildings are main pollutant of the  water  bodies.

Sources of Water Pollution:  

a) Domestic wastes if they are not properly treated and released into water bodies cause serious water pollution.

b) Industrial wastes such as Toxic chemicals, acids, alkalis, metallic salts, phenols, cyanides are released into water bodies causes thermal pollution of water.

c) Agricultural pollutants such as excessive nutrients, ammonia and nitrates, pathogens, antibiotics and hormones.

d) Run off from urban areas such as rainfall and snowmelt can wash natural and man-made pollutants into rivers, lakes, wetlands, and coastal waters.

e) Oil pollution

f) Radioactive waste produced during industrial, medical and scientific processes.

Effects of Water Pollution

Domestic and hospital sewage contain many undesirable pathogenic microorganisms, and its disposal into a water without proper treatment may cause outbreak of serious diseases, such as, amoebiasis dysentery, typhoid, jaundice, cholera, etc. Metals like  lead, zinc, arsenic, copper, mercury  and  cadmium in industrial waste waters adversely affect humans and other animals. Some of the serious effects of water pollution are listed below:

a) Drinking contaminated water causes health problems like cancer, reproductive problems, typhoid fever, stomach sickness and skin rashes in humans.

b) Excess fluoride in water causes defects in teeth and bones called fluorosis, while arsenic can cause significant damage to the liver and nervous system.

c) Oil spills in the water cause animals to die when they ingest or encounter it.

d) Excess radioactive materials in water cause genetic mutations, birth defects and cancer.

e) Excess sediments in water cause cloudiness reducing photosynthetic ability, which disrupts the aquatic food chain.

Control of water pollution

a) The first and most important step in controlling water pollution is to Increase public education and awareness around the world concerning the causes and impacts of water pollution.

b) Government initiatives like Swachh Bharat Mission helps in reducing domestic wastes.

c) Setting up effluent treatment plants to treat waste water.

d) Laws, standards and practices should be established to prevent water pollution and these laws should be modified from time to time based on current requirements and technological advancements.

e) Planting more trees will reduce the amount of sulphur dioxide and nitric oxide.

f) Industrial plants should be based on recycling operations as it helps prevent disposal of wastes into natural waters but also extraction of products from waste.

g) Thermal pollution can be reduced by employing techniques like cooling ponds, wet/dry cooling towers etc.

Air Pollution

We all breathe in air, we can feel, and even smell the air and say whether it is fresh or stale. The pollution in air may not be noticed until we see smoke coming out from some source. All human activities from cooking at home to activities in highly mechanized industries contribute to air pollution.

The World Health Organization defines air pollution as “the presence of materials in the air in such concentration which are harmful to man and his environment.”

In Simple words, it is the occurrence or addition of foreign particles, gases and other pollutants into the air which have an adverse effect on human beings, animals, vegetation, buildings, etc.

Air Pollutants

Pollutants are classified into primary and secondary pollutants.

Primary pollutants: they are emitted into the atmosphere directly from the source and retains the same chemical form. Examples are carbon monoxide, sulphur oxides, nitrogen oxides, hydrocarbons, suspended particulate matter(SPM).

Secondary pollutants: they are formed by the inter mingling and reactions of primary pollutants. Examples are photochemical smog, acid rain, PAN etc.

Sources and causes of Air Pollution

The sources of air pollution are classified into two groups: Natural and Man- made sources.

(a) Natural sources:

1)     Volcanic eruption: releasing poisonous gases like SO2, H2S, CO etc.

2)    Forest fires: Very large quantities of smoke and particulate matter are liberated during their breakout.

3)     Decomposition of organic and inorganic substances: Methane gas, carbon dioxide is released into the air.

4)     Dust: Dust is always present in the atmosphere in varying amount.

(b) Manmade sources:

1)    Deforestation.

2)     Burning of fossil fuels.

3)     Emission from vehicles.

4)     Rapid industrialization.

5)     Modern agricultural practices.

Effects of Air Pollution

Air pollution is very dangerous for health. Some of the adverse effects of air pollution are given below:

1. Air pollution affects our respiratory system and causes breathing difficulties.

2. Diseases such as bronchitis, asthma, lung cancer, tuberculosis and pneumonia caused due to air pollution.

3. Increased concentration of carbon dioxide in atmosphere causes global warming.

4. Air pollution causes acid rain which damages crop plants, trees and buildings. It also makes the soil acidic.

5. Ozone layer depletion due to air pollution which allows ultraviolet radiation to reach the earth. Such radiation causes various skin and eye diseases.

6. Excess nitrogen oxides in the atmosphere results in respiratory problems and bronchitis.

Measures to Control Air Pollution

Air pollution can control from the following points:

1. A raw material for feedstock should be renewable rather than depleting.

2. Better designed equipment and smokeless fuels should be used in houses and industries. Less polluting fuels should be used.

3. Growing plants capable of fixing carbon monoxide. Example: Phaseolus vulgaris, Daucus carota.

4. Growing plants capable of metabolizing nitrogen oxides and other gaseous pollutants. Example: Vitis, Pimis, Pyrus etc.

5. Use of non-conventional sources of energy should be encouraged.

6. Use of public transport to control fuel consumption.

7. Automobiles should be properly maintained and adhere to emission control standards.

8. Proper Environmental Impact Assessment for any developmental work must be done.

Environmental Studies  MCQs  Multiple Choice Questions and Answers

➡ Top 100 Environmental Studies MCQs

Environmental Studies  Chapterwise  Notes

➡ Unit 1: Introduction to Environmental Studies

➡ Unit 2: Ecosystems

➡ Unit 3: Natural Resources: Types, Renewable and Non-renewable Resources

➡ Unit 4: Biodiversity and Conservation (Available in DTS App – Only for Members)

➡ Unit 5: Environmental Pollution

➡ Unit 6: Social Issues and the Environment

➡ Unit 7: Environmental Policies & Practices

➡ Unit 8: Human Communities and the Environment

➡ Unit 9: Field work

Environmental Studies  Question Papers 

➡ Dibrugarh University 2022

➡ Gauhati University 2022

➡ Assam University 2019   2021

➡ Kolkata University (Coming Soon)

Environmental Studies  Solved Question Papers    

Noise pollution.

Noise is one of the most pervasive pollutant. A musical clock may be nice to listen during the day, but may be an irritant during sleep at night. Noise by definition is “sound without value” or “any noise that is unwanted by the recipient”.

Noise in industries such as stone cutting and crushing, steel forgings, loudspeakers, shouting by hawkers selling their wares, movement of heavy transport vehicles, railways and airports leads to irritation and an increased blood pressure, loss of temper, decrease in work efficiency, loss of hearing which may be first temporary but can become permanent in the noise stress continues. It is therefore of utmost importance that excessive noise is controlled.

Noise level is measured in terms of decibels (dB). W.H.O. (World Health Organization) has prescribed optimum noise level as 45 dB by day and 35 dB by night. Anything above 80 dB is hazardous.

Causes and Sources of Noise Pollution

There are several sources of noise that contribute to both indoor and outdoor noise pollution which are listed below:

a) Cutting and Crushing in Industries/ Factories.

b) M ovement of heavy transport vehicles, railways and airports etc.

c) Sound generated during Construction activities.

d) Household chores such as washing and cleaning.

e) Playing of loud speakers during festivals/ social events and also hearing loud music in home.

f) Fire crackers burning during festivals and celebrations.

g) Microphones, Television and radio run in loud voice.

h) Loudspeakers in religious places.

h) Some noises are also caused by nature which are called a tmospheric noise which arises due to spurious radio frequency waves due to lightning and other natural disturbances occurring in the atmosphere. Natural phenomena like lightning, thunder, volcanic eruption, earthquake, sound of the ocean waves, etc.

Effects of Noise Pollution

a) Hearing Problems: Exposure to noise can damage one of the most vital organs of the body, the ear.

b) Poor Cognitive Function: With regular exposure to loud noise, the ability to read, learn and understand decreases significantly over time.

c) Serious diseases: High noise pollution can cause high blood pressure and loss of temperament.

d) Sleep disorders – exposure to noise reduces duration of sleep, diminish quality of sleep, Psychic disorders.

e) Wild life issues – noise bring about changes in the behavioural aptitude of birds and animals. They become inefficient in hunting and hence disturb the balance of ecosystem.

Thermal Pollution

The excessive heat dissipated into air or water from the industries increases the temperatures of the entire ecosystem and hence causes thermal pollution. Industrial waste and heat not only causes widespread climatological changes but also it can cause the damage of aquatic and terrestrial life. The effect of thermal pollution is more prominently marked in aquatic system.

The industries like iron and steel plants, petroleum refineries, nuclear reactor, electronic power plants etc. use large amount of water for cooling purposes. The water carries a lot of heat which when released into nearby bodies leads to thermal power pollution. Such an increase in temperature of the aquatic bodies by 8 to 10 degree celcius becomes injuries to the aquatic life.

When an increase in temperature of the aquatic body affects and disrupts the normal activities of the aquatic living organisms, the process is known as thermal pollution.

Sources of Thermal Pollution

a) Nuclear reactor

b) Industrial Wastes

c) Hydro-electric Power Plant

d) Thermal Power

e) Domestic Sewage

Effects of thermal pollution

Thermal pollution affects the living organism in the following ways:

a) It reduces the dissolved oxygen content of water.

b) It changes the characteristics properties of water.

c) It influences reproductive cycle, digestion rate, respiration rate and many enzymatic activities of living organism.

d) It favours the growth of certain bacteria and pathogens.

e) The egg of fish may hatch early or fail to hatch at all.

f) Thermal pollution results in low dissolved oxygen levels thereby perishing aquatic organisms.

Measures to Control Thermal Pollution

1. Colling of Pond’s water is the simplest and cheapest method to control thermal pollution.

2. Plantation of trees upon the banks of rivers, seas and other water bodies. Trees not only help in controlling thermal pollution but also aid in a better environment.

3. Creating artificial lakes for cooling of ponds.

4. Recycling of used water of factories.

5. Co-generation of heat from hot water and used in different tasks of industries.

Solid Waste Management

Industrialization across the world has brought a lot of good as well as bad things as well. One of the negative effects of industrialization is the creation of solid waste and consequent environmental degradation.

According to Britannica, “Solid-waste management is the collecting, treating and disposing of solid material that is discarded because it has served its purpose or is no longer useful. Improper disposal of municipal solid waste can create unsanitary conditions, and these conditions in turn can lead to pollution of the environment and to the outbreaks of vector-borne disease”

Human and animal activities generate different kinds of wastes. These wastes are generally in solid form, and may cause pollution of land, water and air unless treated and disposed off. The process of collection, transportation, treatment and disposal can be grouped under solid waste management. The increase in the quantity of solid waste is due to overpopulation, affluence and technological advancement.

Bad effects of solid wastes

a) Open dumps are malodorous places in which disease carrying vermins such as rats and files proliferate.

b) Methane gas is released into the surrounding air due to decomposition of solid wastes by the micro-organisms.

c) Hazardous materials dissolved in this liquid contaminate underground water and solid strata.

d) The leachate consisting of a variety of chemical constituents’ seeps and pollute the ground water.

e) Absence of landfill lingers aggravate the problem furthermore.

Types of Solid Waste

Solid wastes (waste which are neither liquid nor gaseous) can be classified into:

a) Urban or municipal wastes

b) Industrial wastes

Sources of Urban Waste

– Domestic wastes: It includes a variety of materials thrown out from homes.

– Food waste, Cloth, Waste paper, Glass bottles, Polythene bags, Waste metals, plastic containers, scrap, paints etc.

– Commercial wastes: It includes wastes coming out from shops, markets, hotels, offices, institutions, etc.

– Waste paper, packaging material, cans, bottle, polythene bags, etc.

– Construction wastes: It includes wastes of construction materials. • Wood, Concrete, Debris, etc.

– Horticulture waste and waste from slaughter houses include vegetable parts, residues and remains of slaughtered animals, respectively.

– Biomedical wastes: It includes mostly waste organic materials

– Anatomical wastes, Infectious wastes, glass bottles, plastic, metal syringe, etc.

– Mining waste: A large amount of solid waste is released from the mining activities. The increase in solid waste is due to overpopulation, affluence and technological advancement.

Sources of Industrial Waste

The main source of industrial wastes are chemical industries, metal and mineral processing industries.

– Nuclear plants: Generate radioactive wastes

– Thermal power plants: Produce solid waste in the form of fly ash 3

– Chemical Industries: Produce large quantities of hazardous and toxic materials.

– Other industries: Other industries produce packing materials, rubbish, organic wastes, acid, alkali, scrap metals, rubber, plastic, paper, glass, wood, oils, paints, dyes, etc.

Measures to Control Solid Waste

i) Sanitary Landfill: This is the most popular solid waste disposal method used today. Disposing of waste in a landfill involves burying the waste, in abandoned or unused places. In this method garbage is spread out in thin layers, compacted and covered with clay, sand or plastic liner. The liners protect the ground water from being contaminated. When the landfill is full, it is covered with layers of sand, clay, top soil and gravel to prevent seepage of water.

ii) Incineration : It is the hygienic way of disposing solid waste. It is a thermal process (controlled combustion) in which the waste material is converted to heat, gas, steam and ash, which can be used for electrical generation and domestic heating. It is suitable for hazardous, organic and medical wastes. Combustible substance should be separated and removed before incineration process. Wet municipal waste should be preheated before incineration process. It reduces the volume of waste up to 20 or 30% of the original volume.

iii) Composting: It is a popular method by which bulk organic matter is converted into fertilizer by biological action. Microorganisms like fungi, bacteria convert degradable organic waste into broken, odourless mass called humus, which is a good fertilizer. Separated compostable waste is dumped in underground trenches in layers of 1.5m and finally covered with soil of 20 cm and left for decomposition.

Sometimes, actinomycetes are introduced for active decomposition. Biological action will start within two to three days. Good quality environmental friendly manure is formed from the compost and can be used for agricultural purpose.

iv) Vermi Composting: It has become very popular in the last few years. In vermi composting, earthworms are added to the compost. These help to break the waste and the added excreta of the worms makes the compost rich in nutrients. It is very useful biofertilizer and soil conditioner.

Related posts:

• Introduction to Environmental Studies [Environmental Studies Notes BCOM/BA/BSC 2nd SEM CBCS Pattern]
• Natural Resources Types, Renewable and Non-renewable Resources

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Pollution of Air and Water

Introduction: what is air pollution and water pollution.

Air pollution has been the highlight of all major international level meetings, air is something we all share and cherish. The presence of breathable air is very important for leading a healthy life, the recent levels of air pollution witnessed around the world has been of serious concern for all the people, different environmentalists like Greta Thunberg, etc have raised their voices forcing the governments to change their policies regarding pollution. Public demand for this has also been very high and as a result, stricter policies have been coming up and all are made aware of the causes and concerns of air pollution.

Air pollution directly affects the health of humans and animals alike. The air humans and animals breathe is directed to the lungs and as such the pollutants present in the air directly get into the lungs and can lead to lung cancers. In the case of animals, several cases of deaths related to air pollution have been witnessed in different parts of the world. Also, birds have been severely affected by the air pollution because they have to be at the core of the polluted air. In recent times, air pollution has been of such several levels that breathing in that air was equivalent to smoking two packs of cigarettes in a day. Air pollution is also very harmful to crops and other agricultural products because when air is highly polluted and rain starts pouring, the rain pours in the form of Acid rain. The acid rain pours on people who are out, the crop produces and finally gets added into the ground. The acid rain can cause skin allergies if exposure to such rain is prolonged and can also damage the crop if caution is not exercised. The addition of acid rain into the groundwater disrupts the PH of the groundwater and as a result the groundwater also gets polluted.

Water pollution has also been of extreme concern for leaders and people around the globe. Several efforts are being implemented to reduce the water pollution levels to the minimum. It is found that the most polluted water bodies are those which are nearer to the residential or the commercial areas. While the water bodies near to the residential areas have got polluted due to the discharge of all the drainage waste into these waters, the one close to the commercial areas has witnessed the release of industrial waste into them as the main cause of water pollution in these areas. Several other water bodies have been witnessed as becoming municipal dumping sites.  

Water pollution is a critical concern because the pollution in water bodies has an extremely severe effect on the lives of aquatic animals and it totally leads to the disruption of aquatic ecosystems there. The huge presence of plastics, water bottles, and polythenes can cause fatal conditions for aquatic animals. Also, the increased water pollution has disturbed the PH level of the water bodies and as a result, water at some points in these water bodies has become so poisonous or acidic that fishes, dolphins, and penguins have often been seen dead at the sea, river shores.  

Air and Water pollution both are very harmful to human existence on this planet. Air and water are the most precious natural resources which are present in abundance but we misuse and abuse them. The pollution in any of these has a serious effect on the lives of humans and animals alike. Air and water pollution if abused to the maximum level can’t be turned back on immediately, several diseases and disorders previously unknown to humans have been identified as a consequence of air and water getting polluted with poisonous substances which are released from chemical and other such environment degrading industries. Like humans, the health of the planet is also getting affected when we choke the air it breezes and pollute the water that flows on it. 

Air Pollution

Air pollution is the exhaustive presence of undesired gasses/particles in the atmosphere. The gasses may be released off due to natural causes like volcanic eruptions etc or maybe released off due to man-made causes like industries or vehicles. Both affect the air quality immensely and make it very harmful for breathing and sometimes extremely toxic. 

Air pollution is caused by releasing various gasses into the atmosphere, finely divided solids, or finely dispersed liquid aerosols at rates that exceed the environment's natural capacity to dissipate and dilute or consume them. These compounds can achieve concentrations in the air that cause unwanted effects on health and the economy.

Air pollution is one of the prime concerns of all countries in the 21 st century, there have been several agreements between countries all over the globe to control their respective emissions and relatively lower the amount of air pollution. India has been severely affected by air pollution, the capital of the country has been reeling under severe air pollution levels where the AQI has been at times the maximum and in the range of hazardous.

Water Pollution

Water pollution is another type of pollution where the water has a heavy presence of undesired entities in it. From oil spills to commercial drainages all add up to destroy the precious water bodies. Water pollution has also been caused by the dumping of waste materials at the depths of rivers and lakes. The presence of plastic bags, bottles have also added up to the pollution of water.

Water pollution is caused by leaking different substances into subterranean groundwater or into lakes, streams, rivers, estuaries, and oceans to the point where the substances interfere with the beneficial use of water or with the natural functioning of ecosystems. Apart from releasing substances such as chemicals or microorganisms , water pollution may also include releasing energy into water bodies in the form of radioactivity or heat.

Causes of Air pollution

Combustion from Industry

Manufacturing processes can produce virtually all the common air pollutants. Some of these are created by the combustion of fossil fuels driving the manufacturing process, resulting in oxides of particulate matter, ozone, and nitrogen.

Transportation Emissions

Popular forms of transport such as cars, planes, and ships typically use combustion to extract fossil-fuel electricity. The combustion process releases pollutants, such as particles and carbon monoxide, into the air and also releases rapidly forming substances into nitrogen oxides and ozone, which are important air pollutants.

Agriculture Side-Effects

Farmers use fossil-fuel-driven machines to plow fields and harvest crops, and animals raised in bulk for food often create their own kind of air pollution. Methane is a gas that contributes to the greenhouse effect causing global warming; it originates from intestinal gas released by livestock.

Volcano Eruptions

Natural processes emit plenty of polluting substances into the air. Sulfur dioxide is a major modern air pollutant and volcanoes can release enough sulfur dioxide into the air to affect global cooling, according to National Geographic.

Forest Fires

Forest fires release pollutants into the air in the same way as pollution produced by fireplaces that burn wood. They produce fine particles of smoke that are small enough to get into the lungs and damage the lungs and heart, according to the EPA.

Tobacco Smoke

Homes in the developing world may have visible smoke coming from the fire used to heat and cook the house. Tobacco smoke is commonly the only noticeable type of air pollution within the home in the developed world. Both sources of indoor smoking are linked with respiratory diseases.

Metal Smelting

Different industries produce specific profiles of air pollutants, and the major source of metal pollution such as lead is metal smelting, while niche applications of lead, such as in the manufacturing of certain aviation fuels, often contribute.

Aerosols and CFCs

Refrigerants are the most common emitter of CFCs, especially those used after the 1930s. When not properly disposed of the coolant used in old refrigerators, cars, air conditioners, and other machines, it leaks CFCs into the atmosphere as liquids evaporate or work their way into the soil.

Causes of Water Pollution

Industrial Waste

Industries produce enormous quantities of waste containing toxic chemicals and pollutants, which causes air pollution and harm to our atmosphere.

Many industries, lacking a proper waste management system, drain the waste into the freshwater that enters canals, rivers, and later into the sea.

Toxic chemicals can change watercolor, increase the number of minerals, called eutrophication, change water temperature, and pose a serious hazard to water organisms.

Sewage and Wastewater

The sewage and wastewater produced in each household is chemically treated and released into the sea along with fresh water. The sewage water contains toxins, a typical water pollutant, other harmful 

Marine Dumping

The garbage produced by households in the form of paper, plastic, food, aluminum, rubber, glass, is collected and dumped into the sea in some countries. These items take 2 weeks to 200 years to decompose.

When such things enter the sea, they not only cause water pollution but also harm animals in the sea.

Accidental Oil Leakage

Oil spill poses an enormous threat to marine life as large quantities of oil spill into the sea and does not dissolve in water. It causes local marine wildlife issues involving fish, birds, and sea otters.

If an accident occurs a ship carrying a large amount of oil can spill oil. Such an oil spill can cause differing harm to ocean species, depending on the amount of oil spilled, pollutant toxicity, and the depth of the ocean.

The Burning of Fossil Fuels

When burnt, fossil fuels such as coal and oil produce considerable amounts of ash in the atmosphere. Particulate matter which contains toxic chemicals when combined with water vapor causes acid rain. Carbon dioxide is also released from fossil fuel burning which results in global warming.

Chemical Fertilizers and Pesticides

The farmers use artificial fertilizers and pesticides to protect crops from insects and bacteria. They are important for the growth of a plant. But they create harmful pollutants for plants and animals when these contaminants are mixed with water.

Also, the chemicals mix up with rainwater when it rains and flow down into rivers and canals, and cause serious damage to aquatic animals.

Leakage from Sewer Lines

A small leak from the sewer lines will contaminate the groundwater and make drinking unsafe for the people. The leaking water can also spill onto the soil when not cleaned on time and can become a breeding ground for insects and mosquitoes.

Global Warming

As a result of the greenhouse effect, an increase in world temperature results in global warming. It increases the water temperature which leads to the death of aquatic animals and marine species resulting in water contamination later on.

Radioactive Waste

The production of nuclear energy is through nuclear fission or fusion. Uranium, which is a highly toxic chemical, is the element used in the production of nuclear energy.

Acid rain is in fact water pollution from air pollution. As air pollution combines the acidic pollutants released into the atmosphere with water vapor, it results in acid rain.

Eutrophication

The increased nutrient levels in bodies of water are known as eutrophication. It results in algae blooming in the atmosphere. It also depletes the amount of oxygen in the water that impacts fish and other aquatic animal populations adversely.

Effects of Air Pollution

Global warming is potentially one of the most troubling consequences for scientists and environmentalists alike. Global warming is a direct result of the greenhouse effect, produced by high CO 2 and methane emissions into the atmosphere. Most of these emissions are produced by manufacturing so that companies and factories can address this with social responsibility and action.

Climate Change

Climate change is yet another result of global warming. When the planet's temperature rises, the usual climatic cycles are disturbed, accelerating the changes of these cycles in an evident way.

Gasses emitted from industry, power stations, boilers, cooking, and transportation are highly toxic. Such gasses contain sulfur dioxide (SO 2 ) and oxides of nitrogen (NOx) released by burning fossil fuels into the atmosphere. When these compounds collect in the atmosphere and react with water, they form dilute nitric and sulphuric acid solutions, and when those amounts are air, both the environment and the surfaces suffer.

Smog Effect

The smog effect or beret effect happens when a sort of dark fog is spread over the towns and fields. The fog is a pollutant load and can be of two types: sulfurous smog and photochemical smog, both toxic and harmful to health. Both sources of smog are the product of industrial and urban practice.

Deterioration of Fields 

Acid rain, climate change and smog cause damage to the surface of the Earth. Contaminated water and gasses flow into the earth, altering soil composition. That affects agriculture directly, the evolving crop cycles and the composition of the food we all consume.

Extinction of Animal Species

As the poles ' ice masses melt and sea levels increase, other animal species which rely on oceans and rivers to survive are endangered. Currents change, ocean temperatures rise and migratory patterns change, and in areas unfamiliar to them, many species are forced to look for food. Deforestation and low soil quality also mean the forests and biodiversity are vanishing. And, probably, a difference in many wild species' behavior.

Respiratory Health Problems

It is perhaps one of the most visible and troubling human effects. Pollutants can cause respiratory diseases and allergies ranging from asthma, cancer, or emphysema to coughs.

Inhalation of toxic agents affects the respiratory system specifically in the lungs and other tissues.

Deterioration in Building Materials

Air pollutants often deteriorate and change the constitution of building materials, thereby degrading, eroding, or damaging many buildings and infrastructure at an increased rate over time.

Effects of Water Pollution

Effects on Human Beings

One of the major effects of this is sickness. The World Health Organization states that around 120,000 deaths related to cholera occur annually. In fact, for example, the Fukushima disaster increased the prevalence of thyroid cancer in untreated children by 70 percent.

Death of Aquatic Life

Polluted water most affects animals and plants which depend on water for life. Statistics on the consequences of the Deep Horizon spill from the Center for Biological Diversity provide valuable insight into the impact of pollution on aquatic life. The 2010 Gulf of Mexico spill injured more than 82,000 birds, 25,900 marine animals, 6165 sea turtles, and an unknown number of fish and Invertebrates in the study.

Food Chain Disruption

Pollution interferes with the food chain by transferring the toxins from one level in the chain to another. Pollution can in some cases wash out a whole part of the food chain. These affect the other species either by causing excessive growth if the predator dies or dies (if the prey is wiped out)

Destruction of Ecosystems

The addition of certain microorganisms or their disappearance distorts the environment. For example, nutrient pollution leads to an increase in algae which depletes oxygen water and leads to the death of fish and other aquatic life.

Economic Effects

The management and restoration of polluted bodies of water are costly. For example, in 2019 Japan announced that storing the contaminated water after the Fukushima accident is running out of space. This currently contains more than one million tons of contaminated water stored in tanks. Research shows that cleanup of the disaster's effects would cost at least $660 billion. 

FAQs on Pollution of Air and Water

1. What is the Main Cause of Air and Water Pollution?

The major causes of air pollution are coal and carbon combustion, manufacturing and chemical production, mining operations, indoor pollution, high-rate renewable gas emissions, etc. A lot of other causes lead to air and water pollution.

2. Explain how Air Pollution and Water Pollution affect the Environment?

Also, air pollution can have a direct impact on water pollution. If pollutants such as sulfur dioxide fall up into the air, they can combine to produce acid rain. Acid rain can turn waterways poisonous and can kill fish and other animals. Water pollution can have major environmental impacts.

3. Is Air Pollution or Water Pollution worse?

Air pollution will become a greater global killer than dirty water ' Urban air pollution is set to become the largest environmental cause of premature death in the coming decades.

Biology • Class 12

Assignment on Pollution

Introduction

Environmental pollution is a multi-disciplinary science involving chemistry, physics, life science, agriculture, medical science, public health, sanitary engineering etc. In broader sense, it is the study of the sources, reactions, transport, effect and fate of chemical species in the air, water and soil and the effect of human activity upon these.

Pollutant : A substance present in nature, in greater than natural abundance due to human activity, which ultimately has a detrimental effect on the environment and therefrom on living organisms and mankind. Examples are- lead, mercury, sulphur dioxide, carbon monoxide, etc.

Contaminant : A material which does not occur in nature, but is introduced by human activity into the environment, affecting its composition. A contaminant is classified as a pollutant when it exerts a detrimental effect. Example- chlorine gas

Types of Pollution

Causes of air pollution:

• motor vehicle exhaust
• power stations
• car manufacturing
• fertilizer factories
• demolishing buildings
• solvent evaporation
• volcanic eruption
• building roads
• forest fires

Effect of air pollution:

Global warming, acid rain, smog, ozone depletion are some effects of air pollution

Causes of water pollution:

• man-made chemicals used in farming
• heavy metals
• waste from factories
• sediment from the river bed
• air pollution
• thermal (heat) pollution
• soil pollution from rubbish dumps

Effects of water pollution:

The water in the earth’s biosphere is used and reused again and again by all living things

Soil Causes of soil pollution:

• mining and quarrying
• household waste
• demolition and putting up buildings
• factory waste

Effects of soil pollution:

Experts say that lots of land each year becomes unusable for humans or animals.

Causes of noise pollution:

• noisy roads and traffic
• air traffic
• rail traffic
• household noise
• industrial noise

Effects of noise pollution:

We hear and make sounds nearly all the time but too much noise can make us feel angry or depressed. The time of day that noises are heard is very important.

Radiation Pollution from radiation can be caused by:

• nuclear power plants
• making nuclear weapons
• disposal of nuclear waste
• mining for uranium

What can happen?

Radiation occurs naturally at low levels and is a useful source of power when concentrated.

It can also be very harmful to all living things if they are exposed to too much of it.

Light pollution happens when outside lights, such as a streetlight or a security light, points light upwards into the night sky.

This light gets scattered in the sky and makes an orange foggy glow to appear above a town.

It is likely that we won’t be able to see the stars in the night sky if the amount of light pollution isn’t closely controlled.

CONSERVATION AND ENVIRONMENT MANAGEMENT

It is imperative that we carefully utilise our renewable resources of soil, water, plant and animal life to sustain our economic development. Over exploitation of these is reflected in soil erosion, siltation, floods, and rapid destruction of our forest, floral and wildlife resources. The depletion of these resources often tends to be irreversible and since the bulk of our population depends on these natural resources to meet the basic needs, it has meant a deterioration in their quality of life.

Global petroleum deposits are likely to be exhausted within this century. Research is going on for alternatives to fossil fuel (petroleum) based on biomass (green energy). Controlled nuclear fusion holds the prospect of abundant energyif the relatively difficult deuterium-deuterium fusion reaction can be utilised for energy production. This energy source will become unlimited.

Solar energy is both renewable and non-polluting and provides ideal energy source. On a global scale, tapping of only a small fraction of solar energy the earth can supply the entire energy requirement.

In any new development project, due consideration must be given to the environmental, social and cultural impacts. For this purpose, environmental experts must be involved in project planning.

NATURAL AND MANMADE DISASTERS

Sometimes there are drastic changes in environment due to natural disasters, e.g. cyclone, typhoon, hurricane, tornado, earthquake, volcanic eruption etc. within a short time.

Bush fires , are another type of natural disasters, are of common occurrence in some regions of the world due to hot summer and lightning. During the hot summer months bush fires are common in Australia and in the Pacific coast arid areas in USA.

Man developed science and technology but over the years since the Industrial Revolution (1780- todate) he continued to plunder natural resources thereby polluting the environment. He degraded lands, destroyed forests, threw toxic wastes into rivers and seas and also harmful gases into the atmosphere. This continuous load of manmade pollutants into environment brought about adverse changes, which ultimately back-fired into series of disasters from time to time.

Some examples of manmade disasters are: London smog, Minamata disease, nuclear explosions, Bhopal disaster, Chernobyl disaster and Gulf War Hazards.

Nuclear Explosions . Two bombs were dropped by USA during World War II (Aug 6 and 9, 1945) on Hiroshima and Nagasaki in Japan. These instantly killed about 6 lakhs people, wiped out the two cities and unleashed radioactive fallout which has caused generations to suffer from various diseases including genetic disorder. Radiation continues to damage plants, soil and biosphere* in the region.

*the environment consists of four segments- atmosphere, hydrosphere, lithosphere and bioshphere.

Global Warming or Green House Effect

Among the constituents of the atmosphere, only carbon dioxide and water vapour strongly absorb infrared radiation (14000 to 25000 nm) and effectively block a large fraction of the earth’s emitted radiation. The radiation thus absorbed by carbon dioxide and water vapour is partly re-emitted to the earth’s surface. The net result is that the earth’s surface gets heated up by a phenomenon called the greenhouse effect .

The current global trend in deforestation along with increased combustion of fossil fuels have a cumulative effect on the net increase in carbon dioxide content (present 356 ppm, 50%). Carbon dioxide has the potential to rival nuclear wars in terms of massive irreversible damage to the environment. It is the major greenhouse gas but there are other greenhouse gases- methane (CH 4 , 19%), chlorofluorocarbons (CFC, 17%), nitrous oxide (N 2 O, 4%) and water vapour (2%).

In september, 1980 scientists reported a large hole in the ozone layer over Antarctica. CFC was the prime suspect for causing ozone depletion. It was established that one molecule of CFC is capable of destroying one lakh O 3 molecule in the stratosphere. The extreme chemical stability and nontoxicity of CFCs enable them to persist for years in the atmosphere and to enter the stratosphere. Depletion of ozone layer above the earth surface helps to penetrate harmful rays from the sun to the earth .

A Report on Garment Industries Bangladesh (Part-1)

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