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  • It's Time to Re-evaluate How we Value Water

    A new study led by researchers from the University of Oxford highlights the rapidly mounting pressure to measure, monitor and manage water on both a local and global scale, and proposes a new four-tiered approach to valuing water to ensure sustainable development and to help improve policy and water usage.

    Water is recognized as a valuable and vital resource for people and cultures, as well as industry, agriculture and the environment. Having access to safe drinking water is essential for human survival and for the long term survival of civilizations. This is reflected in the huge global financial investments in water treatment and sanitation, which is estimated to be approximately US$114 billion annually in capital expenditure alone.


    However, there is a growing need to re-assess the value of water. Not only is water essential for sustaining all forms of life on Earth, it also plays a key role in ensuring sustainable development. For example, all 17 of the United Nation's Sustainable Development Goals recognize the importance of water in achieving the sustainability objectives. These include developing sustainable cities, achieving peace and justice, and alleviating poverty and world hunger.

    Yet, global water security is increasingly becoming an area of growing concern. Droughts, floods and pollution all have a negative impact on water resources and communities. The World Economic Forum has listed water related threats within the top five global risks for a number of years now. A 2015 water security study conducted by Oxford researchers estimated costs associated with flooding, inadequate water supply, water shortages and poor sanitation to be around US$500 billion annually. The World Bank recently highlighted the economic and social impact of water scarcity, demonstrating that a drought costs a city four times as much as a flood event, while in rural Africa, a just one drought can trigger a downward spiral resulting in ongoing poverty and deprivation across generations.

    As economists, scientists and humanitarian aid groups recognize these trends, it is time for us to re-assess the value of water globally. Recognizing that the value of water extends far beyond the monetary value, the UN/World Bank High Level Panel on Water recently launched the Valuing Water initiative, which aims to guide policy and investment decision-making and encourage better governance in terms of managing water resources.

    The paper, which was recently published in Science, outlines a framework that places a value on water according to the Sustainable Development Goals rather than simply placing a monetary value on water or recognizing the cultural benefits of this precious natural resource. To this end, they recommend that water should be valued and managed through a four-prong approach that simultaneously highlights the need for measurement, valuation, trade-offs and capable institutions for allocating and financing water.

    "Our paper responds to a global call to action: the cascading negative impacts of scarcity, shocks and inadequate water services underscore the need to value water better", said Dustin Garrick, a researcher at Oxford University's Smith School of Enterprise and the Environment, who is the lead author of the paper. "There may not be any silver bullets, but there are clear steps to take. We argue that valuing water is fundamentally about navigating trade-offs. The objective of our research is to show why we need to rethink the value of water, and how to go about it, by leveraging technology, science and incentives to punch through stubborn governance barriers. Valuing water requires that we value institutions."

    According to Richard Damania, Global Lead Economist with the World Bank Water Practice and co-author of the paper, the study shows that water is key to development and therefore it is a resource that needs to be managed sustainably. He points out that multiple water management policies will be required in order to achieve multiple goals, and that current policies are outdated and inadequate for meeting current and future water related challenges.

    "Without policies to allocate finite supplies of water more efficiently, control the burgeoning demand for water and reduce wastage, water stress will intensify where water is already scarce and spread to regions of the world - with impacts on economic growth and the development of water-stressed nations," Damania warned.

    Earlier this month the University of Oxford hosted a one day forum, Valuing Water for Sustainable Development, where new approaches to how water is valued, financed and allocated were discussed. Conference presentations focused on several aspects of water management, including:

    1. Challenges to placing a value on water
    2. New tools to address these challenges
    3. Financial solutions to improve water infrastructure globally
    4. Making use of water markets to address water scarcity and shocks

    Oxford's Smith School of Enterprise and Research have released several video interviews with researchers who made presentations at the conference, which can be viewed here.

    Journal Reference

    Garrick, D.E., Hall, J.W., Dobson, A., Damania, R., Grafton, R.Q., Hope, R., Hepburn, C., Bark, R., Boltz, F., De Stefano, L., O'Donnell, E., Matthews, N. and Money, A. (2017) Valuing Water for Sustainable Development. Science. Vol 358. Issue 6366

  • Climate Change May Diminish UV Penetration Allowing Pathogens to Thrive in Waterbodies

    One of the impacts of climate change is extreme weather events that often bring heavy rainfall and flooding to some areas. Heavy rainfall increases organic runoff into freshwater and coastal waters, and according to a study that was recently published in Scientific Reports, may inhibit the sun's ability to penetrate these waterbodies. As UV light is able to kill pathogens, the sun's ultraviolet (UV) rays provide important ecosystem services, ridding rivers, lakes and coastal waters of pathogens. If this ability is diminished, there is a greater likelihood of waterborne pathogens becoming more prolific.


    Research has shown that globally aquatic systems are becoming browner due to the increase in organic material being washed into them from surrounding terrestrial systems — a phenomenon known as "browning". Using a model developed by the National Center for Atmospheric Research (NCAR), this latest study is the first to quantify the impact that dissolved organic material has on limiting the sun's UV rays from disinfecting waterbodies and killing pathogens that lurk in them.

    This not only poses a potential health risk for people who are exposed to pathogens when using waterbodies for recreation, but also poses a potential drinking water safety risk — even if the water has been treated. According to Craig Williamson, an ecologist at Miami University and lead author of the paper, dissolved organic matter doesn't only inhibit the ability of the sun to disinfect water, it also renders the water treatment process less effective. Considering that every year between 12-19 million people already fall ill in the US alone due to exposure to waterborne pathogens, this will in all likelihood cause that figure to rise.

    For the study, the researchers analyzed water samples collected from lakes in the US and other countries to determine the level of dissolved organic matter present in each of the samples and the wavelengths of ultraviolet light absorbed by the organic matter present.

    Then using the Tropospheric Ultraviolet-Visible model — which simulates how UV light is scattered and absorbed as it passes through Earth's atmosphere — the scientists estimated how much of the sun's UV rays reaches the surface of these lakes at different times of the year. They also assessed the amount of reflection and refraction of light from the surface of each lake to determine how much UV light penetrates together with the depth it reaches.

    According to the report, "the Tropospheric Ultraviolet-Visible model also calculates the expected disinfecting power of UV light in a particular body of water based on its dissolved organic matter and other characteristics, a measurement known as 'solar inactivation potential (SIP)'. In some cases, researchers calculated the SIP across different parts of, or for different time periods in, the same lake."

    From there the researchers were able to quantify the impact that dissolved organic matter had on water quality of lakes, as well as drinking water supplies. For example, modeling of water samples collected prior to and following a severe storm from a site on Lake Michigan — a source of drinking water for over 10 million consumers — showed a 22% reduction in SIP due to the additional dissolved organic matter that flowed into the waterbody from just this one storm.

    "Water clarity is dropping in many regions due to factors such as browning, and this research demonstrates that this change is likely decreasing natural disinfection of potentially harmful pathogens," said Kevin Rose, a freshwater ecologist at Rensselaer Polytechnic Institute and coauthor of the paper.

    Journal Reference

    Craig E. Williamson et al. Climate change-induced increases in precipitation are reducing the potential for solar ultraviolet radiation to inactivate pathogens in surface waters. Scientific Reports 7, Article number: 13033 (2017) DOI: 10.1038/s41598-017-13392-2

  • Contaminated Drinking Water Responsible for Thirteen Deaths, Thousands of Illness Cases in US

    If your drinking water is clear it doesn't necessarily mean it is clean. Clear water may harbor invisible pathogens that can be harmful to your health. A new report that was recently published by the US Centers for Disease Control and Prevention (CDC) has revealed that during 2013-2014, 42 health related outbreaks associated with drinking water contamination due to the presence of chemicals, pathogens or other toxins (excluding lead) were recorded in 19 US states.

    The outbreaks, which have increased from thirty-two reported during 2011-2012, caused more than a thousand people to fall ill, with 124 patients requiring hospitalization, and resulted in 13 deaths.

    According to the CDC, a large percentage (57%) of these outbreaks was caused by Legionella, which was also responsible for 88% of cases requiring hospitalization and all of the deaths reported. Legionella, a pathogenic bacteria that can cause the deadly Legionnaire's disease, can also cause legionellosis, which although not as deadly, causes symptoms such as coughing, difficulty breathing, high fever, aching muscles and headaches in those affected.

    Scanning electron micrograph of Leptospira interrogans. Scanning electron micrograph of Leptospira interrogans.

    Legionella bacteria can enter the water supply via various channels, for example, through damaged pipes or as a result of flooding. And while water utilities typically treat drinking water with chlorine before it is distributed along the network, there may be cases where the dosage isn't high enough to ensure water reaching the end of the supply line is adequately treated. So if Legionella bacteria are present and are not sufficiently suppressed at the water treatment plant, their numbers can grow again by the time the water reaches the end of the water distribution network, causing people at the end of the supply line to fall ill.

    Cryptosporidium and Giardia parasites, which both cause an infected person to become ill with diarrhea, were responsible for five and three outbreaks respectively, according to the report, while harmful algal blooms or chemicals were responsible for five of the outbreaks.

    The CDC noted that 75% of the reported illnesses were associated with community water supplies that are regulated according to government safety standards.

    Environmental Exposure

    Over the same 2013-2014 period, the CDC received 15 reports of disease outbreaks as a result of environmental exposure to contaminated water from 10 US states, resulting in 226 people falling ill, 69 of which required hospitalization, resulting in 9 deaths. A further 12 outbreaks resulting from 'undetermined exposure to contaminated water' was recorded for eight US states, resulting in 63 people falling ill, 39 of which required hospitalization, and 8 deaths.

    For the disease outbreaks relating to both environmental and undetermined exposure, Legionella was again found to be the largest cause of illness (63%), hospitalizations (94%) and death (100%), while Giardia accounted for most of the illness cases associated with exposure to contaminated natural water bodies.

    Experts warn that even if your drinking water looks clean, it may harbor microscopic pathogens that can be harmful to your health. It is wise to have your water tested so that you know what is in it. But even if you do, there is always that chance that your water supply may become infected after it shows up as clear. To be on the safe side, it is better to filter your drinking water with a good quality drinking water filter that is capable of removing tiny bacteria and viruses, including Legionella and Giardia that may be lurking in your water supply.

    Journal Reference

    Katharine M. Benedict, et al. Surveillance for Waterborne Disease Outbreaks Associated with Drinking Water — United States, 2013–2014. Morbidity and Mortality Weekly Report (November 10, 2017) Vol. 66 / No. 44 (1216-1221). US Department of Health and Human Services/Centers for Disease Control and Prevention.

    R. Paul McClung, et al. Waterborne Disease Outbreaks Associated With Environmental and Undetermined Exposures to Water — United States, 2013–2014. Morbidity and Mortality Weekly Report (November 10, 2017) Vol. 66 / No. 44 (1222-1225 ). US Department of Health and Human Services/Centers for Disease Control and Prevention.

  • Exposure to Arsenic can Result in Cancer Decades Later

    Arsenic in drinking water is known to pose a health risk to humans, including the risk of cancer. Now a new study has revealed that the carcinogenic effects of arsenic exposure via drinking water may lie dormant for years before cancer develops.

    For the study, which was recently published in the Journal of the National Cancer Institute, researchers tracked mortality rates of Chilean people living in a region where they were exposed to drinking water contaminated with arsenic. The study presents evidence of increased bladder, kidney and lung cancer as much as forty years after exposure to high levels of arsenic ceased.


    Inorganic arsenic is a naturally occurring drinking water contaminant that is found in high concentrations in drinking water in many countries around the world, posing a severe public health threat to millions globally. Health issues associated with extended exposure to arsenic in drinking water include bladder, kidney and lung cancer as well as skin cancer, cardiovascular disease, and other negative health effects.

    In 1958, the drinking water supply for the northern Chilean city of Antofagasta experienced a dramatic rise in arsenic concentrations. In 1970 the local water treatment plant upgraded their facility to include a mechanism for removing arsenic from the drinking water, which led to a dramatic drop in arsenic exposure. As Antofagsta is recognized as the driest place on the planet inhabited by humans, everyone residing there at the time had no other option but to drink the water supply provided by the city, even though it was know to contain high levels of arsenic.

    The study examines the health and mortality of residents exposed to arsenic over time, and identifies 'a clear relationship between and cancer mortality rates'. The researchers found that mortality rates from bladder, kidney and lung cancer started to rise about ten years after residents where exposed to high levels of arsenic, only peaking more than twenty years after measures were put in place to reduce residents exposure to arsenic, with associated cancer mortality rates remaining high for as much as 40 years after residents were exposed to the highest levels of arsenic.

    While the researchers hope to continue monitoring this population, from the results of the study to date, they have already concluded that the delay between arsenic exposure and the onset of arsenic-related cancers makes it a human carcinogen with one of the longest dormancy periods. These findings are not only important in terms of the light they shed on latency patterns of carcinogenic contaminants, they may also have a direct implication on public health.

    The lengthy latency period following exposure to arsenic means that arsenic-related health effects may only materialize years later, which in effect means that the incidence of these types of cancers are likely to remain high amongst populations exposed to high level of arsenic long after these exposures have ended.

    However, it may be possible to take proactive measures to improve the health outcomes of people who have been exposed to high levels of arsenic in the past.

    According to the authors, "possible long-term interventions to reduce mortality and morbidity after high exposures end include disease screening, reducing important co-exposures, heavy metal detox treatments, health services resource planning, and increasing public awareness of arsenic health effects."

    Journal Reference

    Allan H. Smith, Guillermo Marshall, Taehyun Roh, Catterina Ferreccio, Jane Liaw, Craig Steinmaus. Lung, Bladder, and Kidney Cancer Mortality 40 Years After Arsenic Exposure Reduction. JNCI: Journal of the National Cancer Institute, djx201,

  • PFOA Contamination of Drinking Water More Widespread than Initially Reported

    After testing drinking water from public water systems around the country last year, the Environmental Protection Agency (EPA) concluded that 1% of the water samples tested were contaminated with the carcinogenic chemical PFOA which was used in Teflon coatings commonly found on non-stick household products. Besides being associated with cancer, the chemical can damage the immune systems of children and can cause other serious health issues even at low levels. But according the Environmental Working Group (EWG), the company that analyzed the water samples says that it is more likely that over 20% of those samples were contaminated with PFOA.

    A Teflon Coated Pan A Teflon Coated Pan

    The disparity lies in the fact that the EPA only requires public water utilities to report PFOA contamination when it is present above a minimum level, and this level is ten times higher than most laboratories can detect implementing the testing method proposed by the EPA.

    The laboratory that originally analyzed the water samples reanalyzed over 10,000 samples collected between 2013-2015, including samples that contained low levels of PFOA which the EPA were not notified about. They found more than 20% of the water samples contained PFOA. While they didn't assess how many other public water systems this affects, and by extension how many more consumers are exposed to the contaminant via their drinking water, they report that the number of people affected is certainly far higher than the 7 million the EPA acknowledges are affected.

    Chemical manufacturers have pushed for higher reporting limits, voicing their concern that testing labs would struggle to measure a clean sample as the labs themselves were highly contaminated. By pushing the reporting levels for PFOA higher, the EPA is in effect providing a loophole for polluters to get away with contaminating drinking water sources, as the agency only needs to set a legal safety standard if the contamination is considered sufficiently widespread.

    In 2015, after analyzing PFOA data from water samples collected in New Jersey using a far lower level of detection and reporting, the EWG pointed out that using the EPA's level of detection would have missed 75% of the PFOA contamination found by the state.

    But according to the EWG: "Even with the new analysis, all of the PFOA detections nationwide exceed what the best current, independent science says is safe. That level is 1 part per trillion (ppt), which EWG has adopted as a health-based drinking water standard.

    "Based on widespread exposure already occurring through food and other routes, government scientists in New Jersey and Germany say there may actually be be no safe level of drinking water exposure to PFOA and similar compounds in the family of highly fluorinated chemicals known as PFCs or PFASs. Yet the EPA has not set a legal limit for these chemicals, only a non-binding health advisory level of 70 ppt for PFOA and its close chemical cousin PFOS, formerly an ingredient in 3M's Scotchgard."

    Yet some officials are taking the health threat seriously and are taking a proactive approach to protecting consumers from PFOA. New Jersey will be setting a legal safety limit of 14 parts per trillion for PFOA in drinking water, which although still rather high is the highest in the country.

    While PFOA and PFOS chemicals have been phased out due to their associated health risks and are no longer manufactured or used in America, they still persist in the environment. Also, the chemicals used to substitute them have not been adequately tested prior to being rushed into the market to fill the void, and according to the EWG, they too are a source of toxic drinking water contaminants.

    The EWG says that while the PFC contamination risk is not going to go away anytime soon, the EPA has shown no inclination to review and enforce safer limits for drinking water. The EWG advises other states across the nation to follow the lead set by Vermont and New Jersey, and take action to limit contamination of their drinking water by PFOA and other hazardous PFCs.

    The Black Berkey elements that come standard with our Berkey systems do reduce Perfluorinated Chemicals (PFOA, PFOS, PFAA contaminates).  Berkey water filter Perfluorinated Chemical test results can be found here.

  • Arsenic Could Affect Drinking Water of 2 Million Americans

    Many of us who have the privilege of being serviced with supply of safe, treated drinking water tend to take our clean water for granted. But not all Americans get their drinking water from a source that is treated; over 44 million US residents obtain their drinking water from private drinking wells, which mostly go unregulated.

    A report which was recently published in the American Chemistry Society's journal, Environmental Science & Technology, has revealed that around 2 million of those people are in danger of being exposed to dangerous levels of arsenic — a toxic contaminant that is found naturally in the environment — through their drinking water supply.

    A silver / arsenic rock A silver / arsenic rock

    Arsenic is a drinking water pollutant that occurs naturally in soils, and is widespread within the environment. Exposure to inorganic arsenic over an extended period of time can potentially result in a wide range of health issues, and has also been linked to varies forms of cancer. Recent studies also suggest that low-level arsenic exposure in pregnant women can have a negative effect on fetal growth and can cause pre-term births.

    While municipal water utilities typically have water filtration plants that remove arsenic from water, and need to monitor water for arsenic in order to meet regulatory standards, residents who depend on wells for their drinking water are pretty much left on their own. The onus rests on well owners to monitor their water for contaminants, and if any are found, they are responsible for implementing measures to remove these contaminants. To date, nobody has really focused on who may be getting exposed to unsafe levels of arsenic in their drinking water around the country. This study, conducted by Joseph Ayotte together with a team of fellow researchers from the US Geological Survey (USGS) and the US Centers for Disease Control and Prevention aims to fill that void.

    Private drinking water well next to an oil tank. Private drinking water well next to an oil tank.

    In order to map out drinking well arsenic levels, the researchers developed a computer model that incorporated existing data of arsenic levels in drinking water wells around the country. They also took into account factors that can affect the concentrations of arsenic, such as aquifer chemistry, geology, and regional rainfall. The model pin-pointed potential arsenic hotspots which were likely to contain wells that had elevated levels of arsenic exceeding the 10 microgram per liter safety limit for drinking water set by the EPA. Hotspots were mostly concentrated around southern Texas, the Southwest, a stretch of land in the upper Midwest and New England. Based on the areas identified, the researchers estimate that the wells affected provide around 2.1 million Americans with drinking water. Many of the affected people may be unaware of the potential risk these contaminated wells pose to their health.

    The researchers conclude by warning private well owners to have their water supply tested for arsenic, and to take the necessary precautions to prevent exposure to this potentially harmful contaminant. A home drinking water filter fitted with a filter that is capable of removing arsenic is a simple mitigating measure that will render your water safe to drink.

    Journal Reference

    Joseph D. Ayotte et al. Estimating the High-Arsenic Domestic-Well Population in the Conterminous United States. Environ. Sci. Technol., October 18, 2017 (web), DOI: 10.1021/acs.est.7b02881

  • Life in the Gutter May Offer Benefits

    Turns out life in the gutter is not all bad. Scientists have just discovered that gutters lining the streets of Paris are teeming with microscopic life that may help improve water quality of urban storm water runoff.

    The research team, comprised of biologists from the BOREA Biology of Aquatic Organisms and Ecosystems research unit in France and a fellow scientist from the Max Planck Institute for Terrestrial Microbiology in Germany, have found that gutters running alongside Parisian streets provide an oasis for a myriad of microscopic organisms, including fungi, microalgae and sponges, as well as mollusks. These urban aquatic communities may provide beneficial ecological services, for example helping to clean storm water and reducing urban waste by breaking down solid organic matter as well as urban contaminants such as engine oil and vehicle exhaust fumes that could otherwise degrade water quality. Gaining a clearer understanding of what organisms make up these communities, and the ecological niche they fill, can help us better understand the ecological services that gutter ecosystems render.

    A storm water drain in Paris A storm water drain in Paris

    The results of the study, which is the first to shed light on the complex biodiversity of microorganisms living on the streets of Paris, appeared in the October 2017 edition of the ISME Journal.

    After noticing the characteristic brown and green tinge of the water flowing in Paris city gutters, as well as bubbles — which are a tell-tale sign of photosynthesis taking place, BOREA researchers suspected that there may be microalgae present in the water. So they set about analyzing non-potable water samples they collected from various locations to identify what microorganisms were present. Sample sites included street gutters, water outlets located on street curbs that pump water from either the Seine or the Canal de l'Ourcq which is used for street cleaning, as well as water collected directly from the Canal de l'Ourcq and the Seine.

    They identified a remarkable 6,900 possible species of eukaryote microorganisms in the roughly one hundred water and biofilm samples they collected off the streets of Paris. Unicellular diatoms were the most abundant, but other unicellular eukaryotes (organisms with a nucleus and organelles) such as amoebas, Rhizaria and alveolates; fungi (including species that are recognized as decomposers); sponges; and even mollusk species were observed. More surprising, the researchers around 70% of the species detected in gutter water were not present in the non-potable source water. The composition of the microorganism communities varied greatly between the sites sampled, which according to the researchers, suggests they may originate as a result of human activity or that they have adapted to thrive in the specific urban location where they are found.

    The researchers conclude that gutters on city streets and the microorganisms they support seem to represent a unique ecosystem that may have a specific, but as yet undiscovered, ecological role to fulfill. Clearly intrigued, the scientists stress that we need to know more about these microorganisms: What exactly are they? What function do they serve? Do they play a key role as minute curbside treatment plants, helping to clean wastewater? How have they adapted to life on the city streets? Should we be monitoring them more closely? To answer these questions, the researchers hope to expand this study by looking at other forms of life, such as bacteria, over a longer timeframe, and assessing microscopic life in gutter water of other cities too.

  • Prenatal Exposure to Fluoride in Mother's Womb Linked to Reduced Intelligence in Kids

    Pregnant women who have high levels of fluoride in their urine are more likely to give birth to children with lower IQ levels, a new study has found. The study, conducted by a team of researchers from the University of Toronto together with experts from the National Institute of Public Health of Mexico, University of Michigan, McGill University, Indiana University, Mount Sinai School of Medicine and Harvard School of Public Health, is the first study of this size and scope that examines the effect of fluoride exposure across multiple stages of neurodevelopment in children.

    "Our study shows that the growing fetal nervous system may be adversely affected by higher levels of fluoride exposure," said Dr. Howard Hu, Professor of Environmental Health, Epidemiology and Global Health at the Dalla Lana School of Public Health, and principal investigator of the study. "It also suggests that the pre-natal nervous system may be more sensitive to fluoride compared to that of school-aged children."



    For over 60 years, people living in the United States and Canada have been exposed to fluoride in their drinking water as well as dental products, which both have fluoride routinely added in order to prevent dental cavities and strengthen bones. In many other countries around the world it is also added to table salt and milk for the toted health benefits it provides. However, many argue that the health risks far outweigh any health benefits that fluoride offers, and water fluoridation needs to be abolished or at least more strictly controlled. This has fueled a greater interest by the scientific community to explore the issues, particularly the effect that exposure to fluoride has on the developing brains of young children, so that they can provide informed input so that drinking water standards can be regulated accordingly.

    Previous studies have shown that continued exposure to recommended levels of fluoride in Canada and the US can cause some side effects such as mild dental staining, while exposure to fluoride at concentrations 5-10 times higher than the recommended levels can cause fluoride to accumulate in the bones — a condition known as skeletal fluorosis. Yet, according to Hu, "Relatively little is known, with confidence, about fluoride's impact on neurodevelopment."


    The study, which was recently published in the scientific journal Environmental Health Perspectives, looked at data collected from 287 Mexico City mother-child pairs who participated in the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) project, where pregnant women were recruited between 1994-2005, who, together with their children, have been monitored ever since.

    The researchers analyzed urine samples collected from the mothers during their pregnancy, as well as urine samples collected from their children when they were between 6 and 12 years old, to get a clearer indication of the personal fluoride exposure of both the mother and their child.

    "This is significant because previous studies estimated exposures based on neighborhood measurements of drinking water fluoride levels, which are indirect and much less precise measures of exposure. They also looked at children's exposures instead of prenatal exposures or had much smaller sample sizes of subjects to study," explains Dr. Hu.

    The research team then examined the link between fluoride levels in urine and the verbal, quantitative and perceptual performance, as well as memory and motor skills of children at 4 years old, and again when they were between 6-12 years old. They also took other factors that are known to affect child neurodevelopment into account, including: birth weight, gestational age when born, birth order, and child's sex, as well as mother's marital status, socioeconomic status, IQ, education, age at delivery, smoking history and lead exposure.

    The study found that levels of urinary fluoride where slightly higher in pregnant women compared to non-pregnant women in the US and Canada. However, according to Dr Hu, the study's findings don't provide sufficient information to suggest that there is no safe level of fluoride exposure.

    "The potential risks associated with fluoride should be further studied, particularly among vulnerable populations such as pregnant women and children, and more research on fluoride's impact on the developing brain is clearly needed."

    Journal Reference

    Morteza Bashash, Deena Thomas, Howard Hu, et al. Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6–12 Years of Age in Mexico. Environ Health Perspect; (Sept 2017) Vol 125:9; DOI:10.1289/EHP655

  • Can Cloudy Drinking Water Make You Sick

    If you think cloudy drinking water is purely a harmless aesthetic issue, think again. A new study conducted by researchers from Drexel University has revealed that murky drinking water is associated with an increased risk of stomach upsets, sometimes even when it is within the safety limits for water turbidity set by city water safety officials.

    Dr Anneclair De Roose, an associate professor at Drexel University's Dornsife School of Public Health, conducted a review of previous studies that looked at the health effects of water turbidity undertaken at several cities across Europe and North America. She found a link between water turbidity — cloudy water — and acute gastrointestinal illness (AGI) in more than ten studies.


    Waterborne pathogens such as Cryptosporidium, Giardia and norovirus can cause gastrointestinal illness with symptoms that include vomiting and diarrhea. It is estimated that in the US alone, between 12 to 16.4 million people fall ill with AGI each year as a result of being supplied contaminated water.

    Since water turbidity is caused by particles held in suspension, it is thought that these suspended particles may in fact provide a hiding place to protect disease causing pathogens against chemicals used in the disinfection process. Cloudy water can also be an indication that water is contaminated by sediment and other harmful pollutants that have washed into the water source with runoff.

    In order to gain a clearer understanding of whether cloudy water could be used as a tool to indicate whether pathogens are present in drinking water, De Roos and her team assessed a number of previous studies that focused on this issue. The goal of these earlier studies was to assess the risk of contamination of drinking water sources (typically rivers that provided the study cities with water), before water was piped into the city's water distribution system. The earlier studies correlated the level of water turbidity with the number of residents falling ill as a result of acute gastrointestinal illness, on a daily basis.

    After analyzing the previous studies, De Roos determined that turbid drinking water led to an increase in AGI in several of the studies, and not only when drinking water became increasingly cloudy.

    "As expected, the association between turbidity and AGI was found in cities with relatively high turbidity levels, often in unfiltered drinking water supplies," De Roos said. "The findings that go against the conventional wisdom are the associations between turbidity and AGI that were seen at very low levels of turbidity -- levels lower than the regulatory limits."

    One of the study cities, Philadelphia, showed a link between cloudy drinking water and AGI reported in children and older citizens. Yet water turbidity reported in the studies, which were conducted in the 1990s, was in fact relatively low by both current and past standards.

    Because there was some variation in terms of the level of water turbidity that were associated with AGI in the studies, De Roos stresses that it is important that we understand the reason why this is so. Future research on this topic should aim to identify the specific conditions that results in turbidity causing AGI.

    "For example, given a similar range of turbidity, is the association with AGI restricted to a certain season or certain climatic conditions, such as periods of heavy rainfall?" De Roos said. "Furthermore, does the association disappear if a different treatment method is used -- like UV disinfection versus chlorination alone?"

    This could help identify specific conditions that lead to turbidity causing AGI, which would in turn assist water utility managers to monitor their water quality data to quickly spot conditions that may make the water supply vulnerable to contamination.

    "While these types of epidemiologic studies can't give definitive answers, they offer a relatively inexpensive tool for screening water supplies in order to prioritize management strategies and further research," De Roos said.

  • Do the Black Berkey Purification Elements remove leptospirosis from the water?

    We are getting many questions recently regarding the Berkey water filter's ability to remove Leptospira.

    In a nutshell; The upper chamber Black Berkey purification elements that come standard with our berkey systems have been tested to remove viruses 8 times smaller in size than the Leptospira virus. This suggests that contaminants much larger like Leptospira should easily be removed. However, since specific testing of Leptospira has not yet been conducted, the company cannot officially make that claim.

    What is Leptospira?

    Leptospira is a bacterium that exists around the world but is most prevalent in hot, wet climates.

    “Leptospirosis is a bacterial infection caused by certain members of the genus Leptospira. Most people who develop a leptospirosis infection only get mild symptoms, but a bit more serious influenza-like symptoms are also quite common. In a minority of infected persons, leptospirosis develops into the dreaded Weill’s disease. Weill’s disease is a serious condition that can involve liver failure, kidney failure, meningitis and sepsis. Weill’s disease can be lethal.

    Urine and blood from a leptospirosis infected person or animal can contain a sufficient amount of bacteria to spread the disease. A common transmission route for humans is getting urine or blood from an infected animal on damaged skin. Even a tiny skin abrasion can be enough for the bacteria to get into the body. Leptospira bacteria can also enter the body through mucous membranes, e.g. those found in the eyes, nose, mouth and genitals.

    Scanning electron micrograph of Leptospira interrogans. Scanning electron micrograph of Leptospira interrogans.

    When infected blood or urine gets into water or soil, the bacteria can survive there for several months. Contract with contaminated water or soil can be enough to catch leptospirosis, e.g. if you have a small abrasion on your skin or get water/soil onto a mucous membrane. Also keep in mind that water and soil can contaminate food, and food can also be directly contaminated by urine and blood.”

    The size of Leptospira bacteria

    Leptospira are incredibly small – they can pass through the pores in water filters, even those that claim to remove bacteria. They will pass easily through filters with a pore size of more than 0.2 micron, including membrane and charcoal types. High-pressure laboratory filters with a pore size of less than 0.1 micron will block them, but the typical hand-held water filters used by hikers, pool filters and the fitted canisters used in some domestic kitchen appliances are useless at removing leptospires – they are often used to separate leptospires from other bacteria when preparing samples for research, as the leptospires pass through but other bacteria don’t!

    “The Leptospira bacteria are in general about 0.1µm in diameter and 10-20µm in length (0.2 to 0.3 microns in diameter; 6 to 30 microns in length). In comparison, a red blood cell is about 7µm in diameter, so despite being quite long, the very small width of leptospires makes them difficult to see under optical microscopes unless a contrast-enhancing technique such as dark-field is used.”

    Why is the micron size of Leptospira important?

    A “micron” is an abbreviated term for “micrometer”, or a millionth of a meter (1/1,000,000 meters). This is about .00004 inches. For Size comparison, a human red blood cell is about 5 microns across. A human hair is about 75 microns across (depending on the person).” **
    Working down to a smaller scale 1 micron = 1,000 nanometers and .1 micron = 100 nanometers
    The Black Berkey purification elements can reduce viruses down to the nanometer scale, in the tested range of 24-26 nanometers:

    From our FAQ:

    Is the MS2 - Fr Coliphage still known to be a good indicator of virus filtration? At least one article suggests that it might not be. Do you have tests on any other viruses?

    MS2 and Fr Coliphage are two separate virus with two different removal characteristics. That is why they are used as surrogates for other types of virus. These virus were selected, by both the EPA and the Military, because of their small size relative to other virus strains and the difficulty in removing both strains. They each are approximates 24-26 nanometers in size which makes them among the smallest of virus. To see their relative size we would suggest that you visit The University of Utah Cell Size and Scale Chart. These virus are comparable in size on that chart to the Rhonivirus. Therefore, in answer to your question, yes MS2 and Fr Coliphage are the ideal virus for use as indicators of a purification systems ability to remove virus.

    MS2 and FR Coliphage are approx 24-26 nanometers in size (.024 to .026 microns) and have been tested and shown to be removed by the black berkey filter elements.  These 2 viruses are approx 8 times smaller than the Leptospira bacteria at .20-.30 microns, that is currently being found in water.

    Black Berkey Filter Elements Black Berkey Filter Elements

    What additional precautions should be taken if I suspect  Leptospira is in my water?

    The Berkey water purification systems can efficiently purify raw untreated pond, lake and river water. However, always use the cleanest and clearest water possible. As an additional precaution, if using a source of water that you believe might contain extreme viral and bacteriological contamination, it is recommended by the CDC, EPA and other organizations that approximately sixteen drops of plain bleach (sodium hypochlorite) or iodine per gallon be added to treat the source water before purifying. This should kill minute pathogens such as viruses, within 30 minutes. The disinfectant will be removed from the treated water entirely with the Berkey system, including any odor or taste.

    For more information about disinfecting water, please reference the following links. or

    The fact that Black Berkey purification elements have been tested to remove viruses to the nanometer range suggests that contaminants much larger in size, such as Leptospira should also be removed. Nonetheless, since actual testing of Leptospira has not yet been conducted, NMCL can’t officially make that claim.

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