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N2 - Each year, 140,000 water-related deaths occur worldwide. These deaths are rarely true "accidents," because most maritime incidents are caused by lack of preparedness. If you frequently participate in aquatic activities, have you stopped to consider the nature of the threat confronting you? What steps can you take to improve your chances of surviving in the water or on a survival craft? Is your knowledge of the basic principles sufficient to enable you to adapt, improvise, and survive? Reading "Essentials of Sea Survival" prepares you to avoid disaster, even in the worst-case scenario. The book is a compelling, informative, and comprehensive guide to open-water survival. Drawing on historical anecdotes as well as published scientific research, it examines the nature of the many threats confronting the survivor at sea and outlines, in lay terms, the methods you can use to prevent or minimize the dangers. Authors Frank Golden and Michael Tipton are internationally recognized experts in cold-water survival. In "Essentials of Sea Survival" they explain the scientific reasoning behind much of the conventional teaching on open-water survival, dispel many misconceptions about how and why people die at sea, and provide up-to-date information on sustained survival in cold water. The lessons they teach are drawn from classic maritime disasters and personal accounts of near-miraculous survival, as well as carefully controlled laboratory experiments.

AB - Each year, 140,000 water-related deaths occur worldwide. These deaths are rarely true "accidents," because most maritime incidents are caused by lack of preparedness. If you frequently participate in aquatic activities, have you stopped to consider the nature of the threat confronting you? What steps can you take to improve your chances of surviving in the water or on a survival craft? Is your knowledge of the basic principles sufficient to enable you to adapt, improvise, and survive? Reading "Essentials of Sea Survival" prepares you to avoid disaster, even in the worst-case scenario. The book is a compelling, informative, and comprehensive guide to open-water survival. Drawing on historical anecdotes as well as published scientific research, it examines the nature of the many threats confronting the survivor at sea and outlines, in lay terms, the methods you can use to prevent or minimize the dangers. Authors Frank Golden and Michael Tipton are internationally recognized experts in cold-water survival. In "Essentials of Sea Survival" they explain the scientific reasoning behind much of the conventional teaching on open-water survival, dispel many misconceptions about how and why people die at sea, and provide up-to-date information on sustained survival in cold water. The lessons they teach are drawn from classic maritime disasters and personal accounts of near-miraculous survival, as well as carefully controlled laboratory experiments.

SN - 9780736002158

BT - Essentials of sea survival

PB - Human Kinetics

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• Published: 30 November 2022

Access to basic drinking water services, safe water storage, and household water treatment practice in rural communities of northwest Ethiopia

• Zemichael Gizaw 1 ,
• Mulat Gebrehiwot 1 ,
• Bikes Destaw 1 &
• Adane Nigusie 2  

Scientific Reports volume  12 , Article number:  20623 ( 2022 ) Cite this article

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Protecting water from cross contamination at source and point of use is an important strategy to improve water quality. However, water safety measures at the source and point of use may not be implemented in the rural communities. This community-based cross-sectional study was, therefore, conducted among 1190 randomly selected households in a rural setting of northwest Ethiopia to assess access to basic drinking water services, safe water storage, and household water treatment practices. Water service level was determined using JMP criteria and practices that prevent cross contamination of water at point of use were used to determine safe water storage. Results showed that 23.0% of the households had access to basic water services; 37.0% practiced safe water storage; and 15.4% practiced one or more household water treatment methods. Public taps (54.5%) and protected spring (25.1%) were the common water sources to rural communities in northwest Ethiopia. Boiling (43.2%), chlorination or water guard (26.8%), and plain sedimentation (23.0%) were among the household water treatment methods commonly practiced in the area. In conclusion, rural households in the studied region has low access to basic water services. Safe water storage practice was also low in the area and household water treatment is not commonly practiced.

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Introduction

Lack of safe water remains one of the world’s most urgent health issues. People in developing countries have no access to safe and adequate drinking water despite access to safe drinking water is a global priority agenda. In 2015, it was estimated that 56% of the world's population had an unsafe water source 1 . Unsafe water sources are important sources of infectious diseases transmission 2 , 3 , 4 . The global burden of disease study estimated that in 2015, an unsafe water source resulted in 1.2 million deaths and 71.7 million disability-adjusted life years (DALYs) 1 . Access to safe drinking water together with hygiene and sanitation is fundamental to global health. Almost one tenth of the global disease burden could be prevented by increasing access to safe drinking water and improving sanitation and hygiene. Annually, safer water could prevent 1.4 million child deaths from diarrhea; 500,000 deaths from malaria; 860,000 child deaths from malnutrition; and 280,000 deaths from drowning. In addition, 5 million people can be protected from being seriously incapacitated from lymphatic filariasis and another 5 million from trachoma 5 .

Limited access to drinking water services continues to be a major public health problem in Ethiopia. In Ethiopia, provision of safe, accessible, and reliable water is very critical. In rural areas of Ethiopia during 2016, 4% have safely managed services, 30% have basic services, and 26% have limited services. This leaves 40% of the country’s rural population with unimproved water services 6 . According to Ministry of Water, Irrigation and Electricity (MoWIE) estimates, rural water supply coverage reached 63% by mid-2016 7 (or 57% according to the Ethiopian Demographic and Health Survey 2016) 8 , but these assessments were not made based on the JMP service delivery categories.

Source-based water safety measures and protecting water from cross contamination at point of use are important strategies to improve water quality in the water supply system and to minimize associated health consequences. Source-based interventions include designing and construction of improved source that have the potential to protect water from contamination and deliver safe water; community-driven sanitation to protect pollution of the catchment area from human, animal, and agricultural wastes; and source-based water treatment 9 . Water safety measures at point of use include safe water storage and household water treatment 10 , 11 , 12 . However, these safety measures may not be implemented in the rural communities due to limited knowledge, misinformation, negative attitude, and lack of experience toward best practices of alternative water treatment technologies and safe storage 13 . Accordingly, this community-based cross-sectional study was conducted to assess access to basic drinking water services, safe water storage, and household water treatment practice in rural communities of northwest Ethiopia.

Study design and setting

A community-based cross-sectional study with structured observation was conducted among rural households in Central and North Gondar administrative zones of the Amhara national regional state, Ethiopia in May 2016 (Fig.  1 ). Central Gondar zone covers thirteen districts and North Gondar zone covers seven districts. The total population residing in Central Gondar is estimated to be 2,896,928 and it is estimated to be 912,112 in North Gondar zone 14 .

(Source: https://en.wikipedia.org/wiki/List_of_zones_of_Ethiopia#/media/File:Map_of_zones_of_Ethiopia.svg ).

Map of study areas

Sample size calculation and sampling procedures

The sample size (i.e., 1210 rural households) was calculated using single population proportion formula and the target households were included in the study using systematic random sampling technique. The sample size calculation and sampling procedures are described in more detail elsewhere 15 .

Data collection tools and procedures

Structured and pretested questionnaire and spot-check observations were used to collect data. The questionnaire and observation checklists were prepared based on a review of relevant literature. The questionnaire was first prepared in English language and translated to the local Amharic language, and back-translated into English to check consistency. The questionnaire was organized in to three parts: (1) socio-demographic information; (2) access to WASH information; and (3) drinking water sources, handling practice, and household water treatment. Environmental health experts were participated in the data collection process after getting a one day training on the tool. The data collection process and completeness of data was closely supervised.

Measurement of study variables

Access to basic drinking water services, safe water storage, and home-based water treatment were the primary outcomes of this study. Access to basic drinking water services was defined as drinking water from all year round improved source that have the potential to deliver safe water by nature of their design and construction, and include: piped water, public taps, protected wells, protected springs, and protected rain catchments, provided collection time is not more than 30 min for a roundtrip including queuing 16 . Safe water storage was defined as storing water in clean narrow-mouthed and properly covered containers plus withdrawing water from the storage containers by tilting or pouring 17 . Household water treatment is the application of different water treatment options including solar disinfection, chlorination (water guard), filtration, plain sedimentation, or boiling that improve water quality at the point of use 18 .

Data processing and analysis

Data were entered using EPI-INFO version 3.5.3 statistical package and exported into Statistical Package for Social Sciences (SPSS) version 20 for further analysis. For most variables, data were presented by frequencies and percentages. We included predictors to the multivariable binary logistic regression model from the literature regardless of their bivariate p-value to identify factors associated with safe water storage and household water treatment. Statistically significant association was declared on the basis of adjusted odds ratio (AOR) with 95% confidence interval (CI) and p-values < 0.05. Model fitness was check using Hosmer and Lemeshow goodness-of-fit test.

Ethics approval and consent to participate

Ethical clearance was obtained from the Institutional Review Board of the University of Gondar (reference number: V/P/RCS/05/1520/2016). There were no risks due to participation and the collected data were used only for this research purpose with complete confidentiality. Written informed consent was obtained from household heads. All the methods were carried out in accordance with relevant guidelines and regulations.

Sociodemographic characteristics

A total of 1190 households were participated in the current study, with a response rate of 98.3%. The family size in 513 (43.1%) of the households was more than five and 1013 (85.1%) of the households had children. Three-forth, 888 (75.3%) and 643 (59.3%) of the female and male heads, respectively did not receive formal education. About half, 565 (47.5%) of the households reported that they received WASH education and 967 (81.3%) of the households reported that they have been regularly supervised by health professionals. Furthermore, 812 (68.2%) of the households reported that they regularly discussed about health and sanitation issues with their family. Similarly, 524 (44%) of the households reported that they discussed about health and sanitation issues with village health groups (Table 1 ).

Water sources

In the current study, 957 (80.4%) of the households had access to improved water sources and more than half, 649 (54.5%) of the households collected drinking water from public taps (Fig.  2 ). The water sources for 156 (13.1%) households are not all year round and 837 (70.3%) of the households reported that the time for water collection is more than 30 min for a roundtrip including queuing time. The volume of water collected in 1154 (97.0%) of the households was below 20 L per capita per day. Accordingly, 274 (23.0%) (95% CI: 20.7, 25.3%) of the households had access to basic water services (Table 2 ).

Drinking water sources for households (n = 1190) in a rural setting of northwest Ethiopia, May 2016.

Water handling at point of use

Two-third, 795 (66.8%) of the households primarily stored drinking water using narrow-mouthed containers, such as Jerricane. The water storage containers were clean at the time of the survey in 859 (72.2%) of the households and 544 (45.7%) of the households reported that they daily washed or cleaned the water storage containers. Moreover, the water storage containers were properly covered at the time of the survey in 1046 (87.9%) of the households and 768 (64.5%) of the households withdraw water from the storage containers by pouring or tilting. Accordingly, 440 (37.0%) (95% CI: 34.2, 39.6%) of the households practiced safe water storage (Table 3 ).

Household water treatment

The current study revealed that 183 (15.4%) (95% CI: 13.3, 17.5%) of the households practiced one or more household water treatment methods. Boiling [79 (43.2%)], chlorination or water guard [49 (26.8%)], and plain sedimentation [42 (23.0%)] were among the household water treatment methods commonly practiced in the rural households. We also investigated the reasons why households did not treated water at household-level and found that 780 (77.5%) of the households reported that they did not practiced household water treatment methods since they believed that the water is safe and 232 (23.0%) of the households did not practiced household water treatment methods due to knowledge or awareness gap (Table 4 ).

Factors associated with safe water storage and household water treatment

Health education, health supervision, family discussion, maternal education, paternal education, and family size were entered in to the multivariable model to identify factors associated with safe water storage. In the adjusted model, safe water storage was significantly associated with health education, health supervision, and family size. The odds of safe water storage was 1.73 times higher among households who received health education in three months prior to the survey compared with households who did not receive health education (AOR: 1.73, 95% CI 1.30, 2.30). Similarly, households who have been regularly supervised by health professionals had higher odds to safely stored water compared with their counterparts (AOR: 1.63 (1.13, 2.35). Small family sized households had also 1.30 times more odds to safely stored water compared with large family sized households (AOR: 1.30, 95% CI 1.01, 1.67) (Table 5 ).

Health education, health supervision, family discussion, maternal education, water sources, family size, and presence of children in the household were entered in to the multivariable model to identify factors associated with household water treatment. In the adjusted model, household water treatment was statistically associated with health professionals close supervision and family discussion on WASH issues. The odds of practicing household water treatment was 1.91 times higher among households who have been frequently supervised by health professionals compared with their counterparts (AOR: 1.91, 95% CI 1.05, 3.46). Similarly, the odds of practicing household water treatment was 2.15 times higher among households who regularly discussed about WASH issues with their families compared with households who did not regularly discussed about WASH (AOR: 2.15, 95% CI 1.35, 3.43) (Table 6 ).

This is a community-based cross-sectional study conducted to assess access to basic water services, safe water storage, and household water treatment practice among households in a rural setting of northwest Ethiopia. This study found that 23.0% (95% CI 20.7, 25.3%) of the households had access to basic water services; 37.0% (95% CI 34.2, 39.6%) of the households practiced safe water storage; and 15.4% (95% CI 13.3, 17.5%) of the households practiced one or more household water treatment methods. Boiling (43.2%), chlorination or water guard (26.8%), and plain sedimentation (23.0%) were among the household water treatment methods commonly practiced in the rural households.

The proportion of households who had access to basic water services in the current study (i.e., 23%) is comparable with a report of JMP, i.e., 30% of households in rural areas of Ethiopia have basic services 6 . However, the proportion of households with basic services in the current study is lower than reports of the Ministry of Water, Irrigation and Electricity (MoWIE) and the 2016 Ethiopian Demographic and Health Survey. Ministry of Water, Irrigation and Electricity reported that rural water supply coverage reached 63% by mid-2016 7 and 57% according to the Ethiopian Demographic and Health Survey 2016) 8 . This differences might be due to the assessment methods used. In our study, we used the JMP definition to basic services as elaborated in the method part, whereas assessments in the aforementioned reports were not made based on the JMP service delivery categories, i.e., they only considered improved sources, which overestimates the coverage. Moreover, the lower access level to basic services in the current study might be due to the resilience of water sources in dry season since we collected data in the dry season. Most water sources in dry season are unreliable, which leads the community to use unimproved water sources in long distances 6 .

The proportion of households who safely stored water in the current study (i.e., 37%) is comparable with findings of a study in rural households of Oshimili North Local Government Area of Delta State, Nigeria, 40% 19 . On the other hand, the proportion of households who safely stored water in the studied region is lower than findings of studies in three districts of Amhara region, 58.8% 17 and Bona District of Sidama zone, 78.1% 20 . This low-level safe storage practice in the study area might be due to the fact that water storage is affected by traditions such as use of wide-mouthed clay pots. Rural communities preferred to store water in wide-mouthed traditional clay pots because they believe that the use of a clay pot makes the water cool and thus “sweet to drink” 21 , 22 . However, the problem associated with this practice is the way they withdraw water, i.e., dipping of mugs, which largely cross contaminate the water. Moreover, rural communities may not have access to detergents to wash water storage containers due to poor socioeconomic status 23 , 24 , 25 that makes the storage containers unsafe.

The proportion of households who practiced household water treatment in the current study (i.e., 15.4%) is comparable with findings of studies in Degadamot Woreda, northwest Ethiopia, 14% 26 and Assosa Woreda of Benishangul Gumuz Region, 13.2% 27 . On the other hand, it is lower than findings of studies in Southern Ethiopia, 29.9% 28 ; Ameya district of Oromia region, 30.3% 29 ; Gibe District of Southern Ethiopia, 34.3% 23 ; India, 53% 30 ; Zambia, 50% 31 ; Nigeria, 54% 32 ; and Uganda, 76% 33 . The low-level practice of household water treatment in the studied region might be due to knowledge or awareness gap, perceived quality of drinking water, unavailability of treatment options, and cost. As documented in the current study, rural households did not practice household water treatment because of the following reasons: believing that the water is safe (77.5%), knowledge or awareness gap (23.0%), unavailability of treatment options (6.5%), and treatment options are expensive (5.4%). Over all, the low-level practice of household water treatment in the area can be due to psychological factors. Attitude towards water-related technology or behavior is the most important psychological factor to make people treat the drinking water 34 , 35 , 36 .

This study revealed that safe water storage was significantly associated with health education, health supervision, and family size. The odds of safe water storage was higher among households who received health education, who have been regularly supervised by health professionals, and who had small family size. Similarly, household water treatment was associated with health supervision and family discussion. The odds of practicing household water treatment was higher among households who have been frequently supervised by health professionals and among households who regularly discussed about WASH issues with their families. The effect of health education can be justified as health education encourages changes in healthy behaviors and it is an effective strategy to create demand for water safety measures and thereby increase good practice 35 , 37 , 38 , 39 . Moreover, health supervision is effective in improving or maintaining households’ WASH practices. Health supervision is critical in area where there is no other sources of health information and low self-determination to improve WASH 40 . The effect of large family size can be justified that large family number diverts attention of household heads to routine family supports than investing in water safety measures 41 , 42 . Moreover, large family sized households may have economic constrains and so that households may not have opportunities to invest on water safety measures 41 , 43 .

Lastly, to increase the degree to which inferences from the sample households can be generalized to a larger group of population (i.e., population validity), we recruited households at random or in a manner in which they are representative of the population that we wish to study and we granted that every household had an equal chance to be included in the study. In addition, we calculated adequately powered sample size using sample size determination procedures appropriate to objective with appropriate assumptions. Furthermore, our findings could be applicable to other situations and settings which have similar characteristics with the study populations of the current study, such as rural settings in developing countries (i.e., ecological validity). As limitations, the self-reported data may not be reliable since the study subjects may make the more socially acceptable answers rather than being truthful and they may not be able to assess themselves accurately, which might result reporting bias. Moreover, variables we included in the current study to identify factors associated with water handling/management practices are not complete.

Rural households in the studied region has low access to basic water services. This low access to basic water services implies that the community is collecting water from unimproved water sources that results contamination of water with disease causing pathogens and chemicals at the source. Moreover, the proportion of households who safely stored water is low in the area, which may intensify the level of water contamination in the water supply chain. Furthermore, household water treatment is not commonly practiced in the study area that indicates protection of water sources from contamination and source-based water treatment are effective approaches to improve drinking water safety in the area. All these imply that access to safe water in a rural setting of northwest Ethiopia is very critical and the spread of water-borne diseases in the community might be high. The local health department in collaboration with the community and other stakeholders need, therefore, strongly work to design and construct communal water sources that have the potential to deliver safe and adequate water all year rounds. Moreover, maintaining the constructed water sources is important since most of the water infrastructures were damaged. In addition, promotion of water safety measures at point of use, such as safe water storage and household water treatment through health education, health supervision, and village discussions is critical.

Data availability

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

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Acknowledgements

The authors are pleased to acknowledge study participants, data collectors, and field supervisors for participation. Authors also acknowledged the University of Gondar for funding the field work and questionnaire duplication.

The research project was funded by the University of Gondar (grand number: R/T/T/C/Eng./250/08/2016).

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Gizaw, Z., Gebrehiwot, M., Destaw, B. et al. Access to basic drinking water services, safe water storage, and household water treatment practice in rural communities of northwest Ethiopia. Sci Rep 12 , 20623 (2022). https://doi.org/10.1038/s41598-022-25001-y

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Basic Water Survival Training Techniques

The likelihood of becoming panicked when in a water survival situation is very high, and roughly 70% of all people live within an hour of a body of water. This is why it’s so important to practice basic water survival training techniques before finding yourself in a water survival situation. The likelihood of experiencing a water survival situation is higher than most people expect. In the year 2000, over 3,400 unintentional drownings occurred in the United States according to the Centers for Disease Control and Prevention. Here are some basic ways that you can prevent drowning through practicing water survival training techniques.

Treading Water

Typically, children are taught to tread water before they’re allowed to swim in the deep end of the pool. Although this seems like a very simple and basic skill, many people do not know how to tread water. Treading water is staying in a vertical position while in the water to keep your head above the surface of the water. It gives you the ability to keep yourself from becoming submerged, but doesn’t provide enough thrust to go anywhere. This is used mostly to stay afloat and conserve energy when taking a longer swim. A non-swimmer that’s drowning will often splash and kick in an effort to stay above the surface because of a lack of technique. This will cause them to tire quickly and will make it more difficult to stay above the surface for longer, which is why learning to tread water is so very important to water survival. One method of staying afloat through treading water is called flutter kicking. The most common way to tread water, however, is considered the eggbeater kick. This is done by alternating rotation of legs with one leg rotating clockwise and the other counterclockwise.

Bobbing is used to stay alive when the hands and feet are bound. It’s a very good basic water survival technique to learn even if you never expect to be in a situation where your feet and hands are bound in the water. The goal in bobbing is to expel the air in your lungs as you go down under the water. Once you reach the bottom of the lake or pool that you’re in, you will push off hard from the bottom to rise to the surface of the water as fast as you can. Then at the surface you will quickly take in air again. Bobbing is only useful in waters that are not too deep. Most people panic during training to learn how to bob, which is why you should not bind anyone with rope during training. A dolphin kick is a maneuver that can be used with the hands and feet bound to rise to the surface of the water quickly.

Underwaters

Gliding under the surface of the water is called underwaters. The goal of doing an underwaters training session is to increase the lung capacity and practice increasing efficiency. Efficiency equates to swimming 75 feet in fewer strokes than normal. Ideally, one would reach 75 feet in just five or six strokes. You can use a modified breaststroke with a frog kick or a dolphin kick for the legs. Your eyes should be focused on the bottom of the pool while staying alert to avoid crashing into anyone else. Being relaxed throughout this process is especially important as it helps to conserve oxygen. After reaching 75 feet in five to six modified breast strokes, increase the goal to 150 feet.

Always make sure to have a lifeguard or a buddy present when practicing water survival techniques.

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Swimming and Water Survival Competence

• First Online: 26 October 2013

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One broadly accepted definition of competency is that “A competency is more than just knowledge and skills. It involves the ability to meet complex demands, by drawing on and mobilising psychosocial resources, including skills and attitudes, in a particular context” [1]. In this chapter, this definition of competency relating to swimming and water survival involves:Knowledge, such as experience, training, education and knowledge of local hazardsSwimming skills, such as breath and buoyancy control and strokesAttitudesJudgementBehaviour, such as risk taking, risk avoidance and realistic self-estimation

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Stallman, R., Moran, K., Brenner, R., Rahman, A. (2014). Swimming and Water Survival Competence. In: Bierens, J. (eds) Drowning. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-04253-9_30

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Alkaline Water and Longevity: A Murine Study

Massimiliano magro.

1 Department of Comparative Biomedicine and Food Science, University of Padua, 35020 Legnaro, Italy

Livio Corain

2 Department of Management and Engineering, University of Padua, 36100 Vicenza, Italy

Silvia Ferro

Davide baratella, emanuela bonaiuto, vittorino corraducci, luigi salmaso, fabio vianello.

The biological effect of alkaline water consumption is object of controversy. The present paper presents a 3-year survival study on a population of 150 mice, and the data were analyzed with accelerated failure time (AFT) model. Starting from the second year of life, nonparametric survival plots suggest that mice watered with alkaline water showed a better survival than control mice. Interestingly, statistical analysis revealed that alkaline water provides higher longevity in terms of “deceleration aging factor” as it increases the survival functions when compared with control group; namely, animals belonging to the population treated with alkaline water resulted in a longer lifespan. Histological examination of mice kidneys, intestine, heart, liver, and brain revealed that no significant differences emerged among the three groups indicating that no specific pathology resulted correlated with the consumption of alkaline water. These results provide an informative and quantitative summary of survival data as a function of watering with alkaline water of long-lived mouse models.

1. Introduction

Alkaline water, often referred to as alkaline ionized water (AKW), is commercially available and is mainly proposed for electrolyte supplementation during intensive perspiration. Early studies on animal models reported that alkaline water supplementation may exert positive effects on body weight improvement and development in offspring [ 1 , 2 ]. Even biochemical markers were analyzed, suggesting that alkaline ionized water intake can cause elevation of metabolic activity. In particular, hyperkaliemia was observed in 15-week-old rats and pathological changes of necrosis in myocardial muscle were found [ 3 ].

More recently, studies were carried out on alkaline reduced water (ARW), referring to electrolyzed water produced from minerals, such as magnesium and calcium, which is characterized by supersaturated hydrogen, high pH, and a negative redox potential. This hydrogen-rich functional water has been introduced as a therapeutic strategy for health promotion and disease prevention [ 4 ].

Alkaline and electrolyzed water have been shown to exert a suppressive effect on free radical levels in living organisms, thereby resulting in disease prevention [ 5 ]. Various biological effects, such as antidiabetic and antioxidant actions [ 4 ], DNA protecting effects [ 6 ], and growth-stimulation activities [ 2 ], were documented.

Although a variety of bioactive functions have been reported, the effect of alkaline water on lifespan and longevity in vivo is still unknown. Animal alkalization has been shown to be well tolerated and to increase tumor response to metronomic chemotherapy as well the quality of life in pets with advanced cancer [ 7 ]. Therefore, we performed a study based on survival rate experiments, which play central role in aging research and are generally performed to evaluate whether specific interventions may alter the aging process and lifespan in animal models.

2. Materials and Methods

Biological effects of alkaline water were evaluated on a selected population of 150 mice (CD1, by Charles River, Oxford, UK). Pathogen-free mice were purchased and placed in a specific breeding facility. No other animal was present in the room. Contact with animal caretakers was minimized to feeding and watering. The population was divided into 3 groups, each consisting of 50 individuals, as follows:

• Group A: 50 mice conventionally fed and watered with alkaline water produced by the Water Ionizer (mod. NT010) by Asiagem (Italy). The Water Ionizer is a home treatment device for producing alkaline drinking water.
• Group B: 50 mice conventionally fed and watered with alkalized water obtained by dilution of a concentrated alkaline solution (AlkaWater by Asiagem, Italy). AlkaWater is a concentrated alkaline solution for preparing alkaline drinking water.
• Group C: 50 mice conventionally fed and watered as conventional (control group) with tap water. The local water supply was evaluated weekly for assuring the absence of toxins and pathogens. The pH values were in the 6.0–6.5 range.

All procedures involving animals were conducted in accordance with the Italian law on experimental animals and were approved by the Ethical Committee for Animal Experiments of the University of Padua and the Italian health Ministry (Aut. no. 39ter/2011). Efforts were made to minimize animal suffering.

2.1. Histological Examination

Treated aged mice were sampled postmortem and subjected to histological examination. Animals belonging to the populations treated with alkaline water, A and B, were sacrificed after 24 months and compared to mice treated with tap water. Samples from kidneys, intestine, heart, liver, and brain were fixed in 10% neutral buffered formalin, and 4  μ m sections were analyzed by optical microscopy.

2.2. Statistical Analysis

In order to investigate the biological influence of alkaline water on mouse longevity, we employed the accelerated failure time model (AFT) [ 8 ], which allows formally exploring the possible effect on survival curves of the applied three-level treatment, that is, examining the role of group membership as a covariate of lifespan. As a more robust alternative to the commonly used proportional hazards models, such as the Cox model, the use of AFT models is advised in the field of survival analysis when the goal is to investigate if a covariate may affect the lifespan in a way that the life cycle may pass more or less rapidly. In fact, whereas a proportional hazard model assumes that the effect of a covariate is constant over time, an AFT model assumes that the effect of a covariate is to accelerate or decelerate the life course.

The relevance of AFT model for biomedical studies has been already recognized in the literature [ 8 ]. With more specific reference to the issue of aging, Swindell [ 9 ] observed that some genetic manipulations were found to have a multiplicative effect on survivorship which were well characterized by the AFT model “deceleration factor.” Moreover, Swindell [ 9 ] argued also that the AFT model should be utilized more widely in aging research since it provides useful tools to maximize the insight obtained from experimental studies of mouse survivorship.

To perform all calculations, we applied a parametric survival analysis approach using a class of 3-parameter AFT distribution models implemented within the statistical software Minitab, version 17.2.1 [ 10 ]. More specifically, we employed three types of random distributions, namely, log-logistic, log-normal, and generalized Weibull.

The experiment consisted in an initial 15-day acclimatization period. After acclimatization, animals (50, group A) were watered with alkaline water (pH 8.5), obtained by the Water Ionizer (Asiagem, Italy), whereas group B animals (50) were watered with water alkalized at pH 8.5 by a concentrated alkaline solution (AlkaWater by Asiagem, Italy) for 15 days. Group C animals (50), control group, were watered with the local water supply. This period has been identified to gradually accustom the animals treated with alkaline water. At the end of the second period of acclimatization, group A and B animals were watered with alkaline water at pH 9.5 (by the Water Ionizer and by AlkaWater by Asiagem, Italy), while animals of group C were watered with local tap water.

After the first year, the most aggressive individuals were moved to other cages within the same group and an environmental enrichment protocol was employed in order to decrease the hyperactivity. This phenomenon was observed especially in animals of groups A and B.

Table 1 reported basic statistics on mice survival of treated and control animals.

Basic statistics on mice survival by treatment level.

Regarding group A, animals (50) were watered with alkaline water (pH 8.5), obtained by the Water Ionizer (Asiagem, Italy). As for group B, animals (50) were watered with water alkalized at pH 8.5 by a concentrated alkaline solution (AlkaWater by Asiagem, Italy) for 15 days. Regarding group C, animals (50), control group, were watered with the local water supply.

A first look on experimental data is provided in Figure 1 , where nonparametric hazard and survival plots seem to suggest that even if no macroscopic difference emerges, starting from the second year of life mice watered with alkaline Water Ionizer and those treated with AlkaWater overwhelmed control mice.

Nonparametric hazard and survival plots by treatment level. Group A: animals (50) were watered with alkaline water (pH 8.5), obtained by the Water Ionizer (Asiagem, Italy). Group B: animals (50) were watered with water alkalized at pH 8.5 by a concentrated alkaline solution (AlkaWater by Asiagem, Italy) for 15 days. Group C: animals (50), control group, were watered with the local water supply.

In order to explore the possible effect of different treatments, that is, to examine the role of group membership on longevity, we applied a parametric survival analysis approach using a class of 3-parameter survival distributions that represent flexible accelerated failure time, AFT models. First of all, using the Anderson-Darling goodness-of-fit statistic, we compared three specific survival distributions, that is, log-logistic (AD = 6.397), log-normal (AD = 6.519), and generalized Weibull (AD = 6.447). Since the best fitting was shown by log-logistic model, we adopted this one as final survival distribution model. The straight lines in the log-logistic distribution QQ plots (Figures 2(a) and 2(b) ) indicate that this distribution provides a suitable fit to our survival data.

QQ plots using the 3-parameter log-logistic distribution model. (a) Treatment A survival time quantiles (vertical axis) versus treatment C survival time quantiles (horizontal axis); (b) treatment B survival time quantiles (vertical axis) versus treatment C survival time quantiles (horizontal axis).

Finally, by including our treatment as covariate, we performed a parametric distribution analysis whose results are graphically represented in Figure 3 .

Distribution plot results using the 3-parameter log-logistic model. Group A: animals (50) were watered with alkaline water (pH 8.5), obtained by the Water Ionizer (Asiagem, Italy). Group B: animals (50) were watered with water alkalized at pH 8.5 by a concentrated alkaline solution (AlkaWater by Asiagem, Italy) for 15 days. Group C: animals (50), control group, were watered with the local water supply.

Starting with the second year of life, it is worth noting that both alkaline water treated groups denote a decreasing hazard curve over time, while the corresponding curve for control group is monotonically increasing. To more formally compare the treatment levels, the proposed analysis provided also suitable p values. Since the p values related on the null hypotheses of equality of location, scale and threshold parameters were, respectively, less than 0.001 (for both locations and scales) and 0.634 (for thresholds) at a 5% significance level; we can state that there is enough experimental evidence to conclude that the treatment significantly affects the mice longevity; in particular the alkaline water provides a benefit to longevity in terms of “deceleration aging factor” as it decreases the hazard functions when compared with the control group. Note that the treatment effect cannot be directly related to no one of the three distribution parameters. Anyway, using the estimated parameters, it should be possible to provide an estimate for the effect of each treatment on survivorship: setting the reference survival time to 1000, 1200, and 1400 days, Table 2 summarizes the estimated point and 95% interval survival probabilities by each treatment level.

Table of survival probabilities by treatment level. The probabilities, along with their related 95% confidence interval limits, were calculated using the normal approximation.

As final remark, it should be noted that even if our parametric AFT survival analysis was performed using the log-logistic distribution, our conclusions are consistent with results obtained using the generalized Weibull distribution, while via log-normal distribution no significant effect was found.

3.1. Histological Examination

No significant differences emerged from the histological examination among the three groups. In all examined samples, renal tissue was characterized by a mild-to-moderate lymphoplasmacytic interstitial infiltrate and few occasional glomerular changes as glomerular size reduction and increasing of Bowman's space ( Figure 4 ).

Kidney, a specific chronic nephropathy. Focal interstitial mainly lymphocytic infiltrate (upright) and a sclerotic glomerulus (middle right). Hematoxylin and Eosin.

Final diagnosis was mild chronic progressive nephropathy for the three analyzed mouse groups.

The microscopic examination of the liver revealed a multifocal nodular pattern of the parenchyma and diffuse mild-to-moderate hepatocellular cytoplasmic hydropic degeneration with multifocal binucleation in all explored animals ( Figure 5 ).

Liver, aging change. Hepatocellular abundant dishomogeneous cytoplasm, binucleation (center), variably sized nuclei, and a nuclear pseudoinclusion cyst (arrow). Hematoxylin and Eosin.

Mild-to-moderate anisokaryosis was the most relevant alteration, with few pleomorphic nuclei and frequent intranuclear pseudoinclusions and karyomegaly. A specific mild perivascular infiltrate was occasionally present. Final diagnosis was mild-to-moderate diffuse hepatopathy with multifocal hyperplastic hyperplasia.

The pulmonary parenchyma showed mild multifocal areas of interstitial thickening of the interalveolar septa due to moderate congestion and mild cellular mixed infiltrate ( Figure 6 ). Mild areas of emphysema were detected at the periphery of the parenchyma. Final diagnosis was multifocal very mild atelectasis and mild vicarious emphysema.

Lung, mild atelectasis. Very mild multifocal interstitial thickening of the alveolar septa associated with congestion and mild cellular increase. Hematoxylin and Eosin.

At the same time, no relevant histopathologic histological changes have been noticed in intestine ( Figure 7 ), brain, and heart.

Intestine. Longitudinal section of duodenum showing uniformly thin and elongated villi. Hematoxylin and Eosin.

4. Discussion

The present work presents a 3-year survival study on a population of 150 mice and the data were analyzed with accelerated failure time (AFT) model. Kaplan-Meier statistical analysis of the survival data indicates the possibility of a positive effect of alkaline water on mouse lifespan and AFT model allowed evaluating differences starting from the second year of the survival curves. These results provide an informative and quantitative summary of survival data as a function of watering with alkaline water on long-lived mouse models. It should be pointed out that, from the standpoint of aging research, this statistical approach presents appealing properties and provides valuable tools for the analysis of survival. The observation of tissues of deceased animals was performed for the assessment of the state of internal organs to be compared with similar analyses of untreated animals. The renal lesions observed at histology were specific and common for the three animal groups. Chronic progressive nephropathy has been well described as normal aging change in mice [ 11 , 12 ]. In our cases animals did not show any clinical sign of nephropathy or any other histological evidence of specific kidney disease and we ascribed the lesions to the aging process [ 11 , 12 ].

The examined livers were also affected by typical lesions of mature subjects, such as hyperplastic nodules. Furthermore, well known aging changes were individuated in the hepatocytes, such as karyomegaly, nuclear pleomorphism, and pseudoinclusions cysts [ 11 , 12 ].

5. Conclusions

A 3-year survival study on a population of 150 mice was carried out in order to investigate the biological effect of alkaline water consumption. Firstly, nonparametric hazard and survival plots suggest that mice watered with alkaline water overwhelmed control mice. Secondly, data were analyzed with accelerated failure time (AFT) model inferring that a benefit on longevity, in terms of “deceleration aging factor,” was correlated with the consumption of alkaline water. Finally, histological examination of mice kidneys, intestines, hearts, livers, and brains was performed in order to verify the risk of diseases correlated to alkaline watering. No significant damage, but aging changes, emerged; organs of alkaline watered animals resulted to be quite superimposable to controls, shedding a further light in the debate on alkaline water consumption in humans.

Acknowledgments

This paper is dedicated to the memory of Tommaso Nicoletti. The authors are grateful to Rocco Palmisano for original ideas and support. The authors would like to thank Asiagem (Italy) for partial support and Ludovico Scenna, Carlo Zatti, and Silvano Voltan for their scientific and professional contribution.

Competing Interests

The authors declare that there are no competing financial interests.