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  • Elevated Risk of Bladder Cancer in New England Linked to Arsenic in Private Drinking Water Wells

    A recent study has revealed that the increased risk of bladder cancer observed in residents of New Hampshire, Vermont and Maine over the last 50 years is likely due to high levels of arsenic found in private drinking water wells, particularly in wells that were dug between 1900 and 1950, and was not believed to be due to other bladder cancer risk factors such as occupational exposure to arsenic or smoking.

    The study, which was conducted by a team of researchers from the National Cancer Institute (NCI), together with researchers from the Geisel School of Medicine at Dartmouth, New Hampshire; the US Geological Survey (USGS); and the health departments of Maine, Vermont and New Hampshire, was published in the Journal of the National Cancer Institute.


    New England has seen higher than normal mortality rates due to bladder cancer for more than fifty years. Bladder cancer rates in Vermont, Maine and New Hampshire have been around 20% higher than that generally recorded across the United States, with higher than normal bladder cancer rates being found in both men and women. What distinguishes this region from many others is that a high percentage of the population living there obtain their drinking water from private wells, which are not serviced by municipal water utilities and are not subjected to EPA regulations for drinking water quality. These wells could be contaminated with arsenic, which is known to increase the risk of bladder cancer when present in drinking water at high concentrations.

    Arsenic in these drinking water wells can stem from two sources: 1) it can occur naturally in soils and rock, leaching into the water from underground; or 2) it can originate from arsenic-laden pesticides that were extensively used on crops in the early 1900s.

    "Arsenic is an established cause of bladder cancer, largely based on observations from earlier studies in highly exposed populations," said Debra Silverman, Sc.D., chief of the Occupational and Environmental Epidemiology Branch, NCI, and senior author on the study. "However, emerging evidence suggests that low to moderate levels of exposure may also increase risk."

    Comparing a sample of 1,213 New England residents that had recently been diagnosed with bladder cancer against a sample of 1,418 residents without bladder cancer living in the same region, the researchers determined that while smoking and occupational exposure increased the risk of bladder cancer in this population, the associated risk due to these factors was still the same as that of people living elsewhere, which according to Silverman: "suggests that neither risk factor explains the excess occurrence of bladder cancer in northern New England."

    Using current arsenic levels and historical data, the research team estimated the total amount of arsenic ingested by each person via their drinking water consumption. They found that the risk of bladder cancer increased as the cumulative exposure to arsenic increased. When the researchers focused on subjects who obtained drinking water from private water wells, they found that residents who consumed high amounts of water were nearly twice as likely to succumb to bladder cancer as those who consumed the least amount of water.

    If water was consumed from dug wells — shallow wells, with a depth of less than 50 feet that are more vulnerable to arsenic contamination from human sources — this association was even stronger still. This risk was significantly higher in people who had been using dug wells as their drinking water source before arsenic-based pesticides were banned in 1960 compared to those that began using dug wells for drinking water later.

    While the threat of arsenic exposure from dug wells is lower now since arsenic-laden pesticides have been banned and dug wells are less common than they were in the past, arsenic exposure in private drinking wells that are drilled deep into fractured underground rock still poses a public health threat. The EPA has set the drinking water standard for arsenic at 10 micrograms/L for municipal water utilities; owners of private drinking wells are encouraged to have their drinking water tested and to take measures to limit their exposure, such as making use of an effective drinking water filter (such as a Big Berkey System with Black Berkey filters) that is capable of removing arsenic from drinking water.

    Journal Reference

    Baris D… Silverman DT, et al. Elevated Bladder Cancer in Northern New England: The Role of Drinking Water and Arsenic. Journal of the National Cancer Institute, May 2016 DOI: 10.1093/jnci/djw099

  • BPA, a Chemical Commonly Found in Plastics, Linked to Pre-term Births

    Bisphenol A, more commonly known as BPA, is a chemical pollutant that is known to have many serious health implications. Now, new research has revealed that it may also be responsible for pre-term births.

    A recent study conducted by Ramkumar Menon, an assistant professor in the department of obstetrics and gynecology at The University of Texas Medical Branch at Galveston, together with collaborators from Winthrop University Hospital and Kaiser Permanente Southern California, has found that moms-to-be who had higher concentrations of BPA in their bloodstream were more likely to give birth early compared to pregnant women who had lower concentrations of BPA in their blood, indicating that BPA may be a contributing factor in premature births.

    attribution: attribution:

    For the study, which recently appeared in The Journal of Maternal-Fetal & Neonatal Medicine, the researchers analyzed blood samples taken from expectant women as they were admitted into hospital during labor, as well as from fetal amniotic fluid samples collected during the birth.
    BPA is a widespread environmental contaminant that is widely used in the manufacture of plastic food containers and beverage bottles, as well as plastic linings in tins used to package canned foods. BPA can leach into food packaged in these containers, and this release can be increased when packaged food is heated in a microwave oven or other heat source. BPA can also leach out of plastic beverage bottles when exposed to heat (including sunlight) during transportation and preparation, compromising products that are considered healthy, such as bottled water for example. Because it is so widely used, women are continually exposed to the contaminant.

    "In fact, BPA is so widely used that nearly all women have some level of exposure," said Menon.

    BPA is similar in structure to the hormone estrogen, which it mimics within the female body, binding to estrogen receptors, including receptors that control inflammation. This can result in abnormal inflammation, which can increase the risk of complications associated with pregnancy, including water breaking earlier than expected and premature birth. This study is the first to investigate the role of high BPA concentrations in the blood to increased risk of premature birth.

    "Widespread use of BPA in materials of our daily life and our findings that all patients have some level of exposure suggests that contact with these materials is unavoidable," Menon said. "This suggests that a better understanding of how BPA may alter maternal physiology is needed to minimize the risk of adverse pregnancy outcomes."

    The researchers are now busy conducting studies on cells taken from fetal membranes and the uteruses of pregnant women to determine the molecular pathways and to identify potential targets that can be used for medical intervention.

    Journal Reference:

    Faranak Behnia, Morgan Peltier, Darios Getahun, Cheryl Watson, George Saade, Ramkumar Menon. High bisphenol A (BPA) concentration in the maternal, but not fetal, compartment increases the risk of spontaneous preterm delivery. The Journal of Maternal-Fetal & Neonatal Medicine, 2016; 1 DOI: 10.3109/14767058.2016.1139570

  • The Importance of Maintaining Ecological Balance in Freshwater Systems

    Plants are primary producers that provide food and nutrients that support herbivores and ultimately predators as well. Without plant life, nothing else would survive. In aquatic systems, plant life consists of single celled microscopic plankton, as well as vascular plants. Both play a key role in freshwater ecology.

    Healthy Freshwater System

    Nutrients are essential for both plant and animal growth. Herbivores get their nutrients from plants, and carnivores get their nutrients from herbivores. But as primary producers, plants and algae get their nutrients from the environment in the form of nitrates, phosphates and minerals. By transforming these nutrients into carbon by harnessing energy from the sun in the process of photosynthesis, plants are able to sustain other life on earth.

    In a healthy, balanced freshwater ecosystem, photosynthesizing aquatic plants absorb nutrients and carbon dioxide from the water column in the presence of sunlight, transforming them into carbon and releasing oxygen in the process. This oxygen allows aquatic animals, such as fish and freshwater invertebrates to survive underwater. Should oxygen be depleted, these aquatic organisms would die. The animals in turn release carbon dioxide which is absorbed by the plants. The ecosystem is healthy and balanced.

    Unhealthy Freshwater System

    Nutrients occur naturally in the environment as a result of decomposition and other processes, but are also added to the environment by man made activities. These include runoff of fertilizer and animal waste products from agricultural practices, from sewage runoff and discharge from wastewater treatment plants, which can result in nutrient loading. When excessive nutrients flow into a waterway, both unicellular algae and aquatic plants take advantage of the available nutrients and will flourish, removing these 'contaminants' from the water in the process.

    However, when conditions are favorable, aquatic plants can quickly multiply to form dense algal blooms or mats of weed that cover the surface of a pond or lake. The system rapidly becomes unbalanced, often with dire consequences.

    In the case of unicellular algae, the algal cells rapidly grow and reproduce while nutrients and light are abundant, but once the nutrients in the surface water are depleted they have to move deeper to find nutrients to sustain them. Eventually there is insufficient nutrients in the surface layers, and as light cannot penetrate the deeper water layers, there is insufficient light in the deeper, nutrient rich layers. When this point is reached, the algae cells die off and sink to the bottom of the lake, where they decompose. Oxygen is stripped from the water during the decomposition process, resulting in water that is low in oxygen, which can result in mass mortality of fish and other aquatic organisms that require oxygen to survive.

    Aquatic plants, especially fast growing non-native species that herbivores tend to avoid, can also spread rapidly, clogging waterways and making it difficult for fish and other organisms to move about with ease. Aquatic organisms may die or move away. A once thriving ecosystem, home to a rich biodiversity and abundant wildlife is reduced to a monoculture of impenetrable aquatic weed.

    Balance is Key

    Aquatic plants play a vital role in maintaining ecosystem health and supporting biodiversity. However, it is essential that the ecosystem remains in balance for it to function effectively.
    Algal blooms and the spread of invasive aquatic plants are both likely to occur more frequently in the future as a result of climate change, more intensive agricultural activities, ecological imbalances, and/or as a result of invader species changing ecosystem dynamics. We therefore need to find creative ecologically sound solutions to maintain balanced freshwater ecosystems and to protect biodiversity.

  • Fertilizing Crops Today Will Contaminate Drinking Water Supplies for Decades

    Dangerously high concentrations of nitrates in water originating from application of fertilizer to crops is likely to persist in drinking water supplies for decades, posing a serious health risk — including increased potential for blue baby syndrome, according to a recently published study conducted by scientists from the University of Waterloo, Canada.

    Nitrogen from nitrogen-based fertilizers, which are commonly applied to agricultural crops to enhance growth and productivity in an effort to increase yields, has been washing into freshwater systems through run-off, and leaching into private water wells for over 80 years. As a result, even if farmers stopped using nitrogen-rich fertilizers today, nitrate concentrations in these freshwater systems will remain at elevated levels for several decades, according to the report, which was published in Environmental Research Letters.

    By Lynn Betts - U.S. Department of Agriculture, Natural Resources Conservation Service. Photo no. NRCSIA99241, Public Domain, By Lynn Betts - U.S. Department of Agriculture, Natural Resources Conservation Service. Photo no. NRCSIA99241, Public Domain,

    The scientists found that nitrogen is accumulating in soils, effectively creating a source of nitrates that will continue to pollute surface and ground water systems for a very long time.

    "A large portion of the nitrogen applied as fertilizer has remained unaccounted for over the last decades," said Nandita Basu, a professor in the Department of Earth and Environmental Sciences and Civil and Environmental Engineering. "The fact that nitrogen is being stored in the soil means it can still be a source of elevated nitrate levels long after fertilizers are no longer being applied."

    This research study is the first to provide direct evidence of the impact of broad-scale nitrogen use in the Mississippi River Basin.

    Iowa's largest supplier of drinking water, Des Moines Water Works, is suing three counties further upstream for failing to take adequate measures to reduce dangerously high nitrate levels in surface waters, which are more than double the safety standard set for drinking water, and which according to the researchers will most likely stay high for many years to come. This oversight has forced Des Moines Water Works to spend millions on upgrading their water treatment facilities in order to supply consumers with water that is safe to drink.

    Professor Basu together with her fellow researchers analyzed historical data from more than 2000 soil samples taken across the Mississippi River Basin. Their results revealed that nitrogen systematically accumulated in agricultural soils over time. In many cases, nitrogen accumulation was not evident in the upper soil layer, but rather at 10-40 inches (25-100 cm) below the soil surface.

    "We hypothesize that this accumulation occurred not only because of the increased use of fertilizers, but also increases in soybean cultivation and changes in tillage practices over the past 80 years," said Kim Van Meter, a doctoral student in the Department of Earth and Environmental Sciences in the Faculty of Science.

    Results from their modeling simulations suggest that the accumulated 'legacy' nitrogen could continue to leach into freshwater systems more than 30 years after farmers stop applying nitrogen to their fields.

    Unfortunately this has ramifications for both environmental and human health. Elevated nitrogen levels in freshwater and marine systems causes hypoxic conditions that result in dead zones where no life can survive, and negatively impacts the quality of drinking water. Exposure to high levels of nitrates in drinking water can cause serious health issues, including blue baby syndrome that can be fatal to infants.

    Over the last forty years or so, policymakers and farmers have been working together to limit the amount of nitrogen fertilizer leaching from fields to underground and surface water systems. Yet, even with these measures, some areas have nitrate concentrations that are more than 10 times the safety standard set for drinking water.

    "The presence of this legacy nitrogen means it will take even longer for best management practices to have a measurable benefit," said Professor Basu, also a member of the Water Institute. "If we're going to set policy goals, it's critical we quantify nitrogen legacies and time lags in human impacted landscapes."

    Journal Reference:

    K J Van Meter, N B Basu, J J Veenstra, C L Burras. The nitrogen legacy: emerging evidence of nitrogen accumulation in anthropogenic landscapes. Environmental Research Letters, 2016; 11 (3): 035014 DOI: 10.1088/1748-9326/11/3/035014

  • Growth in Clean Energy May Increase Pressure on Water Resources

    Efforts to mitigate climate change in the energy sector could result in growing pressure on freshwater sources.  In turn, this could lead to water shortages in other sectors, including domestic water supplies, according to a study that was recently published in Environmental Research Letters. However, increasing energy efficiency together with focusing more on solar and wind power, which are less water dependent, or adopting cooling technologies that are more water-efficient, could help alleviate these pressures, the study reveals.

    The study, which strives to systematically highlight the key areas of water usage in the energy sector, examined forty-one potential energy production scenarios identified by the International Institute for Applied Systems Analysis (IIASA) in their Global Energy Assessment (2012) as being compatible with keeping future global temperature rise within the 2°C target.

    "While there are alternative possible energy transition pathways which would allow us to limit global warming to 2°C, many of these could lead to unsustainable long-term water use," explains lead author, Oliver Fricko, a researcher with the International Institute for Applied Systems Analysis (IIASA.) "Depending on the energy pathway chosen, the resulting water use by the energy sector could lead to water allocation conflicts with other sectors such as agriculture or domestic use, resulting in local shortages."

    The energy sector currently uses approximately 15% of all global water usage, but this could increase by over 600% by 2100 compared to water usage in this sector in the year 2000. The bulk of this water is used by thermoelectric power stations — including power stations powered by fossil fuels or biomass, nuclear power stations, and solar power stations — that require water for cooling.


    However, water usage in not the only issue of concern. When water is pumped from rivers (or the ocean) and used for cooling power plants, it is discharged back to the source once it has circulated through the power plant. The water that is released is much warmer than when it was drawn into the plant — an environmental problem referred to as thermal pollution — which can impact aquatic life in both freshwater and marine systems. According to the study, the incidence of thermal pollution is likely to rise in future unless steps are taken to minimize such pollution by developing and implementing new technologies that mitigate these impacts.

    The study also highlights the role that energy efficiency plays in reducing the pressure on water resources. According to Simon Parker, an IIASA researcher and co-author of the paper, the easiest way to minimize the pressure placed on our water resources by the energy sector is to reduce energy use by improving energy efficiency; particularly in developing nations, where demand for electricity is expected to increase substantially in the future ahead.

    The study, which builds on a recently published IIASA research study that shows the impact of climate change on water resources has the potential to impact energy production capacity, highlights the need for an integrated approach when trying to analyze and understand the global challenges relating to water, energy and climate.

    According to the Director of IIASA's Energy Program, Keywan Riahi, these findings have major implications for the way in which climate change mitigation strategies should be implemented.

    "Energy planners need to put more emphasis on the local water impacts, since they may limit policy choices," say Riahi. "Ultimately we need integrated strategies, which maximize synergies and avoid trade-offs between the water and climate change and other energy-related objectives."


    Fricko O, Parkinson SC, Johnson N, Strubegger M, Van Vliet MTH, Riahi K, (2016). Energy sector water use implications of a 2-degree C climate policy. Environmental Research Letters 11 034011 doi:10.1088/1748-9326/11/3/034011

  • Flint Just the Tip of the Iceberg - Country's Lead Problem Extends Beyond Flint

    The recent fallout over the high levels of lead in Flint's drinking water, has highlighted not only the problems this Michigan city is facing in terms of its drinking water quality, but also wider concerns regarding the country's aging drinking water distribution network.

    With Earth Day approaching, Jerald Schnoor, a Professor of both Occupational and Environmental Health and Civil and Environmental Engineering at The University of Iowa, has called on government to provide funding to upgrade the nation's water distribution system by replacing deteriorating lead water pipes that distribute drinking water across the country.

    Typical Rusted Water Pipe Typical Rusted Water Pipe

    In an article recently published in the ACS' Journal of Chemical Education, Schnoor addresses the problem head-on and proposes recommendations on how best to tackle the issue.

    For many cities across the US — particularly cities in the eastern parts of the country — the water distribution infrastructure was established long before the health risks associated with lead exposure due to lead contamination in drinking water became apparent. Many of these cities' water distribution networks consist of lead pipes, lead solder and lead faucets that were installed over 50 years ago — and in some cases over 100 years ago — posing a potentially significant health risk to the communities they serve. Furthermore, the plumbing inside older homes typically consist of lead piping and pipe joints sealed with lead solder, as well as brass tap fittings that contain a high lead component. All these plumbing fixtures and fittings can potentially provide a source of soluble lead which can leach into the household's drinking water. The problem is exacerbated if the water passing through these pipes is corrosive, which can cause the pipes to become corroded, resulting in fine lead particles being deposited into the drinking water.

    Modern research has since shown that ingesting lead can have dire health effects in both children and adults, and can result in numerous long term cognitive and other health issues. Yet these legacy lead water pipes remain, delivering drinking water that is potentially contaminated with lead to communities across the country.

    While water utility companies typically try to take preventative measures to limit lead getting into drinking water by adding chemical additives, according to Schnoor, this approach cannot ensure that drinking water will remain safe all along the network until it flows out of a household tap.

    Schnoor suggests that the U.S. Environmental Protection Agency (EPA) needs to address the flaws in the Safe Drinking Water Act to ensure that drinking water quality not only meets safety standards when it leaves the water treatment facility, but that it remains safe to drink when it flows from the consumer's taps. To get a clearer picture of true water quality, sampling needs to be undertaken more frequently, and include points further along the distribution network, including 'dead-ends' within the network and at customer's taps (including both filtered and unfiltered water samples).

    According to Schnoor: "Lead pipes are a hazardous legacy, much like the waste sites of old."

    He suggests that a national fund be set up to finance the replacement of the outdated water infrastructure, including the service pipelines that link to the home, as well as the internal plumbing within the home, even though this is the homeowners property — for example, funds will need to be set aside to assist economically disadvantaged families living in an old house that is in need of a plumbing upgrade.

    Journal Reference

    Jerald L. Schnoor. Recognizing drinking water pipes as community health hazards. J. Chem. Educ., 2016, 93 (4), pp 581–582. April 12, 2016. DOI: 10.1021/acs.jchemed.6b00218
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  • Wastewater Treatment Facilities Release Significant Amounts of Microplastics into Rivers

    Microplastics are an emerging pollutant in our oceans, becoming an increasingly worrying environmental problem. Yet, while these tiny plastic beads originate from land-based sources, making their way to the ocean via rivers, very little is known about their abundance and impact on our freshwater systems. According to a new study, these tiny bits of plastic escape through wastewater treatment filtration mechanisms, and are discharged into rivers where they can pose a risk of contaminating drinking water and food sources.

    Microplastics are defined as tiny bits of plastics with a width of less than 0.20 inches (5 mm) — that are now recognized as an emerging ocean pollutant that is harmful to marine organisms.
    Yet while most of the debris that enters our oceans — including plastics — gets transported there via rivers, we have very little understanding about how these microplastics enter rivers or how they affect river ecosystems, says Timothy Hoellein, an assistant professor at Loyola University Chicago.

    Many communities rely on rivers as a source of drinking water, notes Hoellein; they are also important habitats that support a variety of wildlife. Fish and freshwater invertebrates ingest these tiny bits of plastic, which then move up the food chain, ultimately ending up in the fish we eat. It has already been recognized that microplastics floating in the oceans harbor toxic pollutants as well as bacteria that can pose a health risk to animals and humans who ingest them. Microplastics in rivers pose a similar threat.

    "Rivers have less water in them (than oceans), and we rely on that water much more intensely," Hoellein said.

    In a previous study, Hollein found that water samples from a site downstream from a wastewater treatment facility had higher concentrations of microplastics than water samples from a site further upstream. Now, a new study of ten Illinois urban rivers conducted by Hoellein and his research team supports these initial findings. While the study estimates that around 90% of the incoming microplastics is being arrested by the wastewater treatment facilities, due to the exorbitant amount entering the treatment plants, the 10% that escapes into rivers (estimated between 15,000 - 4.5 million particles per day per plant) is still significant.
    In 8 out of the 10 rivers studied, microplastics originated from wastewater treatment facilities. The new study found that these micoplastic particles harbored bacteria that posed a greater health threat than bacteria found in the river water from which they were extracted.

    "[Wastewater treatment plants] do a great job of doing what they are designed to do - which is treat waste for major pathogens and remove excess chemicals like carbon and nitrogen from the water that is released back into the river," Hoellein said. "But they weren't designed to filter out these tiny particles."

    The study also shows that microplastics remain in the environment for long periods of time, and very often are transported a long way from their original source. As these microplastics are transported downstream they are introduced into different ecosystems, making their way through multiple foodwebs in each of these systems.

    According to Hoellien, scientists are currently trying to ascertain what percentage of plastic remains in rivers, and what percentage makes its way to the ocean. By studying microplastics in our rivers, scientists hope to gain a better understanding of the complete lifecycle of these tiny, but dangerous, bits of plastic — from where they originate on land, to how much ends up in our oceans.

    "The study of microplastics shouldn't be separated by an artificial disciplinary boundary," he said. "These aquatic ecosystems are all connected."

  • Do we Really Need to Disinfect Drinking Water?

    Some countries in Western Europe hold a different view to the US when it comes to treating drinking water with residual disinfectants to render it safe to drink. But which of these two perspectives is right? An article recently published in Science compares these two different approaches and tries to answer this question.

    In order to eliminate microbes such as E. Coli and other bacterial contaminants in drinking water, countries such as the US, UK and others require drinking water to be treated with a residual chemical disinfectant such as chlorine. However, these disinfectants typically result in the formation of byproducts that are corrosive, have an unpleasant taste and smell, and can be carcinogenic.

    Furthermore, there is very little evidence to prove that treating drinking water with residual disinfectants actually prevents outbreaks of water-borne diseases. A comparative analysis of recent water-borne disease outbreak data from the United States and the United Kingdom compared to the Netherlands shows that even though it doesn't use residual disinfectants to treat drinking water, the risk of water-borne disease is lowest in the Netherlands.


    The authors point out that the Netherlands has been proactive in keeping its water infrastructure up to date, replacing more than 50% of its water piping in recent years. By comparison, water infrastructure in both the UK and the US is old and outdated, consisting of aging, leaking pipes with reduced water pressure, which increases the risk of contamination by bacterial pathogens. With the rate of leakage in the Netherlands estimated at a mere 6%, compared to 16% in the US and 25% in the UK, the lower leakage rates in the Netherlands may account for the lowered risk of bacterial contamination.

    While the authors suggest that more data is needed to provide conclusive evidence, the European approach suggests that it is possible to supply safe drinking water without disinfecting with a residual chemical treatment. Obviously this is assuming the infrastructure that delivers the water is well maintained, with minimal leakage, thus reducing access points for bacterial drinking water contaminants to enter the system. That may be a tough nut to crack in the US and UK, but may worth the attempt in progressive minded towns and cities with recent infrastructure builds.

    A segment of Science's weekly podcast with Fernando Rosario-Ortiz, related to this research can be viewed at:

    Journal Reference:

    Fernando Rosario-Ortiz et al. How do you like your tap water? Science. 26 February 2016. VOL 351 ISSUE 6276 (pp 912-914).

  • Watershed Biogeochemistry is Influenced by Stormy Weather

    A new study led by researchers from Yale University suggests that severe storm events cause excessive amounts of organic matter to circumvent headwater systems, resulting in this material being pushed downstream where it flows into larger rivers, inland basins and coastal waters, having profound effects on water quality throughout the watershed.

    The study, which was recently published in the scientific journal Ecology, has found that this phenomenon not only affects water quality, but also the ecology and chemical processes that take place within these ecosystems. Dissolved organic material — which consists of a mixture of various compounds that leach into freshwater systems that gives streams and rivers their color — is also a source of nutrients and contaminants, and it has a large influence on light penetration into the water and the release of carbon dioxide from the water, which consequently affects abundance of phytoplankton — primary producers at the bottom of aquatic food chains that are directly and indirectly a key food source for a wide range of organisms.


    Until now, scientists have believed that organic matter is naturally processed in the upper stretches close to its origins, broken down by freshwater organisms dwelling in these headwaters into new compounds, which are then carried downstream and processed by organisms living further downstream, with a similar process occurring right throughout the freshwater system — a process that scientists refer to as the "River Continuum Concept".

    However, this new study highlights the fact that this process doesn't take heavy storm events into account, which send "pulses" of organic material into waterways. Not only are large amounts of debris pushed downstream during these events, because the flow rate is much faster during heavy storm events, they are pushed beyond the headwaters before the above reactions have had time to take place — a theory referred to as the "pulse-shunt concept."

    "We predict that a lot of this organic matter is actually shunted past the small streams and the reactions occur in the larger rivers or even in the coastal ocean," said lead author, Peter Raymond, a professor of ecosystem ecology at the Yale School of Forestry & Environmental Studies (F&ES). "We also offer a new conceptual theory for watershed biogeochemistry that demonstrates this through first principles and is transferable to other watersheds and other nutrients."

    Previous studies estimated that around 60% of organic matter originating from terrestrial sources occurs over 15 days, including days where heavy rainfall or snow melt occurred.
    According to Raymond, even though heavy weather occurs infrequently, more organic matter is transported from the landscape during heavy storm events than in smaller events, as the concentration of the material increases in relation to the size of the event. However, he points out that the 'shunt', or flow rate, during these more severe events results in more material flowing downstream as there is insufficient time for it to be processed by organisms further upstream. As a result, we see a "double additive effect" where more of this organic material is exported to coastal waters," explains Raymond.

    According to the authors, these shifts in the transportation of dissolved organic matter could potentially affect water clarity, dissolved oxygen concentrations, and could also be a source of mercury to inland freshwater systems.

    This clearly has implications for drinking water quality too. While turbidity and dissolved solids can affect the appearance of drinking water, making it unpleasant to drink, the suspended organic matter can also harbor contaminants such as mercury, making it unsafe to drink.

    Journal Reference

    PA Raymond, JE Saiers & WV Sobczak. Hydrological and biogeochemical controls on watershed dissolved organic matter transport: pulse-shunt concept. Ecology. Vol 97(1). Jan 2016; DOI: 10.1890/14-1684

  • Drugs found in Cape Cod Water Wells

    The safety and quality of our nation's drinking water sources are increasingly being questioned, after residents in Flint, Michigan, as well as other regions have recently been found to have contaminated water supplied to their homes. Now a new study has found that pharmaceutical drugs and chemicals found in every-day consumer products can find their way into private drinking wells via wastewater discharged into septic systems. The findings add to growing health concerns related to unregulated chemical pollutants commonly found in household drinking water.

    While conducting the study, which was recently published online in Science of the Total Environment, scientists from the Silent Spring Institute discovered 27 unregulated chemical pollutants, including 12 different pharmaceutical drugs, chemical compounds used to manufacture flame retardants, non-stick coatings, and an artificial sugar-free sweetener.

    It is estimated that around 44 million people in the US depend on private wells for their drinking water. Yet, unlike public water wells, private drinking wells are not regulated by water officials; instead, residents are solely responsible for ensuring that water quality within their wells meets federal safety standards. Not only are private wells monitored less frequently, they are typically also shallower than public drinking wells, and thus more vulnerable to contamination from farming activities, construction, and local landfills. Consequently, contamination of drinking water in private wells continues to present an ongoing health risk to residents in many areas of the country.

    photo credit: photo credit:

    Households that get their drinking water from private wells typically also make use of private septic systems for treating their wastewater. It is estimated that around 25% of all US homes make use of a septic system for treating household wastewater. Earlier studies conducted at Cape Cod by Silent Spring scientists revealed that hormone-disrupting pharmaceuticals and chemicals can leach through soils to contaminate both surface water and groundwater. According to lead author, Dr Laurel Schaider, a scientist at the Silent Spring Institute, the next step was to determine whether these contaminants could find their way from groundwater into household drinking water sources.

    To find the answer to this key question, Dr Schaider and her research team took water samples from 20 private drinking water wells across Cape Cod and tested them for 117 pollutants. They found that around 70% of the wells tested positive for PFCs (perfluoroalkyl substances) — a class of fluorinated chemicals that are sometimes referred to as PFASs. PFCs are known endocrine-disrupters that are associated with developmental disorders and cancer. These chemicals are commonly found in every-day household products, such as non-stick frying pans, pizza boxes, stain-resistant rugs and carpets, and waterproof clothing.

    The scientists found that 25% of all wells tested contained chemicals used in flame retardants, and found a staggering 60% of the tested wells contained pharmaceutical drugs. The antibiotic, sulfamethoxazole, which is commonly prescribed for infections of the urinary tract, together with carbamazepine, a pharmaceutical drug that is prescribed for the treatment of bipolar disorders, seizures and nerve pain, were amongst the more common drugs encountered.
    The researchers also assessed nitrate concentrations in the wells, and discovered that water in wells that had higher nitrate levels also tended to have more contaminants, and these were found in higher concentrations. The researchers note that all water samples came from wells that were situated in areas that were served by septic wastewater treatment systems, and closer analysis revealed that these backyard septic systems were most likely the source of the contamination.

    According to Schaider, this study is the first to show that septic systems can be a source of PFCs in private drinking wells, and considering that 85% of Cape Cod residents use septic treatment systems, the risk associated with contaminated drinking water is a serious health concern.
    Nitrates are also a drinking water contaminant that pose a serious health risk at high concentrations. Yet, while the EPA has set standards for nitrate levels in drinking water, there are none for the chemical contaminants found during the course of this study. While the levels of pharmaceuticals found in this study were considered to be much lower than those typically prescribed for a therapeutic dose, that doesn't necessarily lessen the risk notes Schaider.

    "Drugs are intended for specific uses and can have side effects," she says. "And we don't give certain medications to pregnant women or children because the developing body is very sensitive."

    People may also be allergic to certain drugs, such as antibiotics; and endocrine disrupting chemicals, such as flame retardants and PFCs, may produce adverse effects at very low doses. Furthermore, little is known about the health effects of exposure to a concoction of different chemicals found in drinking water.

    "People often don't think about where their tap water comes from," says Schaider. "But it's really important that they do and that they take steps to make sure it's safe."

    Households that depend on private wells for their drinking water should have the water tested annually. While these tests typically assess nitrate and bacterial concentrations rather than unregulated chemicals originating from household wastewater, this study shows that high nitrate levels could indicate the presence of other chemical pollutants.

    The current safety standard for nitrate in drinking water is set at 10 parts per million (ppm). However, the researchers found PFCs and pharmaceuticals in well water that had nitrate concentrations of less than 1 ppm. If you get your drinking water from a private well that has nitrate concentrations that are below the health standard set by the EPA, yet greater than 1 ppm, you should consider filtering your drinking water with a filter system to remove any pollutants that may contaminating your water. But as prevention is better than cure, to prevent these chemicals from making their way into the environment in the first place, we should limit our use of medications that contain toxic chemicals, refrain from flushing unused pharmaceuticals down the loo or drain, and where possible, move backyard septic systems away from drinking wells and ensure that they are well maintained.

    Journal Reference

    Laurel A. Schaider, Janet M. Ackerman, and Ruthann A. Rudel. Septic systems as sources of organic wastewater compounds in domestic drinking water wells in a shallow sand and gravel aquifer. Science of the Total Environment. 2016. doi:10.1016/j.scitotenv.2015.12.081

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