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  • Aquatic Food Chains Threatened by Hydropower Hydropeaking

    Aquatic insect populations have declined in many rivers downstream from hydroelectric dams, threatening fish and other wildlife that depend on them for survival. Now researchers from the US Geological Survey (USGS) together with collaborators from Oregon-, Utah- and Idaho State Universities, have found that hydropeaking — a practice widely used in the management of hydroelectric dams that involves increasing river flow rates during the daytime when demand for electricity is high — is likely the cause. Their findings suggest that these negative impacts could be mitigated if alternative hydropower methods were used.

    Aquatic insects form a vital part of food webs in freshwater ecosystems and provide the primary source of food for many different species, including fish, reptiles, bats and birds, as well as other wildlife. The study, which was recently published online in the scientific journal BioScience, assessed the impact that sudden changes in water levels have on aquatic insects at all stages of their lifecycle, and provides the foundation for determining how to improve the health of rivers downstream from hydropeaking dams all over the world.

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    The study was partly assisted by data collected in a citizen science project where educational groups, river guides and other citizen scientists collected over 2,500 insect samples from a stretch of Colorado River downstream from the Glen Canyon Dam in the Grand Canyon. The researchers compared insect diversity of 16 large dammed river systems across the western regions of the US that have varying degrees of hydropeaking to assess how the impact of abrupt changes in water levels affected river health.

    "For the first time, this study determines the ecological impacts of hydropeaking separated from other dam-imposed stressors, and identifies the specific cause-and-effect relationships responsible for biodiversity loss below hydroelectric dams," explains lead author Ted Kennedy, a USGS scientist. "These results may help resource managers improve river health while still meeting societal needs for renewable hydroelectricity."

    Hydroelectric power provides approximately 19% of the electricity used globally, and far exceeds that produced by wind, solar or other renewable energy sources combined. Many hydroelectric dams practice hydropeaking, where the volume of water released can vary dramatically within a day, resulting in large hourly shifts in river levels that create artificially induced tides along the shoreline of rivers, which freshwater organisms simply are not adapted to cope with.

    Many insects of ecological importance, such as mayflies, stoneflies and caddisflies, attach their eggs onto a substrate such as aquatic vegetation or rocks that are submerged just beneath the surface of the water, where the eggs soon hatch. But should water levels drop rapidly, exposing the eggs to the sun and air, they can become desiccated causing the larvae to die within the egg before hatching.

    "These large daily rises and peaks in river flows due to hydropower dams are not normal. Prior to the construction of dams, there were almost no major daily changes in river levels in places like the Grand Canyon," said David Lytle, a professor at Oregon State University and co-author of the paper. "This can interrupt the egg-laying practices of some species, and the impact of this was poorly appreciated. Until now, no one really looked at this aspect, and our results show that it causes serious problems for river health."

    For decades, aquatic scientists have been puzzled by the conspicuous absence of stoneflies, mayflies and caddisflies on the Colorado River in the Grand Canyon. This study sheds light on the reason for their absence — the hydropeaking activities of Glen Canyon Dam is partly responsible. The researchers suggest some mitigation measures that dam managers may want to consider, including maintaining low, stable water levels in rivers during times when power demands are low, such as over weekends, to give insects a couple of days to successfully lay (and hatch) their eggs.

    "If mitigation flows are successful, a more diverse community of aquatic insects should improve the health of the Colorado River ecosystem in Grand Canyon, including the largest remaining population of endangered humpback chub," said Kennedy.

    With over 2,500 samples collected by citizen scientists over a 3-year period, this project highlights the important contribution that citizen science makes to research of this nature. The research team partnered with Grand Canyon Youth who provided over 150 samples, to the project — watch them in action here. Having this extensive dataset enabled scientists to reach scientific conclusions which would otherwise have not have been possible.

    "Many urgent questions in ecology remain unanswered, because scientists are bumping up against data limitations where it is impossible for them to collect sufficient data to answer complex questions across large landscapes," notes Kennedy, pointing out that this study highlights the powerful contribution citizen scientists can make to fundamentally advancing knowledge and gaining valuable new scientific insights.

    Journal Reference
    Kennedy TA et al. Flow Management for Hydropower Extirpates Aquatic Insects, Undermining River Food Webs. BioScience (2016) 66(6) doi: 10.1093/biosci/biw059

  • The Dark Side of Anti-Bacterial Soap

    Almost every home in the US uses a variety of household products that contain the anti-bacterial agent triclosan. It is commonly used in the soaps we use for washing our hands or washing our laundry, the toothpaste we use for brushing our teeth, as well as a host of other everyday cleaning products. Consequently, as we go about our daily hygiene or cleaning routine, we are more than likely adding triclosan into our freshwater sources via our wastewater.

    Triclosan is routinely added to toothpaste, antibacterial soaps, household detergents, paints, carpets, and even toys, and while the germ-wary consumer may find some comfort in knowing their family is protected from germs, the reality is that most of these products, especially antibacterial soaps, don't offer much more protection than using normal soap and water.
    Yet triclosan poses a problem — not only does it kill bad bacteria, it also kills beneficial bacteria. Research has shown that triclosan has given rise to antibiotic resistance, making treatment of common ailments and illnesses with antibiotics less effective. Triclosan also poses an environmental risk; it is harmful to algae, and can disrupt normal hormone functioning -- and thus development -- in wildlife. The FDA is busy conducting studies to determine the health risk it poses on humans.

    Credit: Credit:

    While it is believed that the majority of triclosan is removed during the wastewater treatment process, the US Geological Survey (USGS) has found traces of triclosan in approximately 58% of streams tested.

    "What you use has an impact even though you're probably not thinking about it," says Monica Mendez, an associate professor in the Department of Biology and Chemistry at Texas A&M International University, and lead author of a research paper that was recently published in the Journal of Environmental Quality. "If a river happens to be a source of irrigation, could triclosan possibly get into our food?" Mendez asks.

    In order to gain a better understanding of how tricolosan-contaminated water affects soils and plants that are irrigated with it, Mendez and her research team used triclosan-contaminated water to irrigate tomatoes, onions and exposed soil. When the crops were harvested, the researchers detected triclosan in all edible parts of both plants. However, this was at levels considered safe for human consumption.

    The researchers also found that even though triclosan broke down rapidly in soils, it never broke down completely. Instead, it breaks down into other harmful hormone disrupting compounds that can be even more detrimental than triclosan.

    The researchers are also concerned about the effect that triclosan has on bacterial communities living in soils, which are necessary for healthy plant growth. Because triclosan indiscriminately targets both good and bad bacteria, it not only kills disease-causing bacteria, but beneficial bacteria too. Plants tend to flourish in soils that have a thriving and diverse microbial community, but these bacterial communities can be negatively impacted by triclosan.

    "We know that triclosan decreases the diversity of bacterial communities," says Mendez, "But we still need to figure out which good bacteria we are losing."

    This is the first study that measures the effects of long-term, repeated exposure to triclosan on soils and plants. Mendez hopes that future studies will assess the impact that triclosan has on soil microbes.

    "Because we're all concerned about disease-causing bacteria, we generally ignore what happens below ground," Mendez says. "Water and soil come together. We need to look at the quality of both, because food is important."

    Journal Reference
    Monica O. Mendez, Erika M. Valdez, Eileen M. Martinez, Melissa Saucedo, Brittan A. Wilson. Fate of Triclosan in Irrigated Soil: Degradation in Soil and Translocation into Onion and Tomato. Journal of Environment Quality, 2016; 45 (3): 1029 DOI: 10.2134/jeq2015.07.0386

  • Surge in Water Use in North Dakota Attributed to Oilfield Expansion and Influx of Temporary Oilfield Workers

    The surge in water use in North Dakota's rapidly expanding oil industry is not only due to increasing demand as a result of more oil wells, but is also attributed to the influx of people to the Bakken oil shale region, according to a study recently conducted by the US Department of Energy (DOE).

    The recent expansion of oil fields in the Bakken shale region has drawn thousands of oil workers into the area. Between 2010-1012, approximately 24,000 temporary oil industry workers flocked into the area, boosting Williams County's existing permanent population of 27,000 considerably.

    According to Corrie Clark, an environmental systems engineer in the Argonne National Laboratory's Environmental Science Division, and a co-author of the paper which was recently published in Environmental Science & Technology: "It is estimated that the average household in the North Dakota Bakken region uses about 80 to 160 gallons of water a day. If each new temporary worker used 80 gallons a day, their total would be more than half the water used for hydraulic fracturing alone. If they used 160 gallons a day, it would exceed the total amount of water used for hydraulic fracturing. Either way, water use by new temporary workers accounts for a big share of the region's increased water use."

    The Bakken shale consists of an oil deposit that lies beneath parts of Montana and North Dakota (US), and Manitoba and Saskatchewan (Canada). The annual water consumption for hydro-fracking has risen dramatically since 2008 when annual consumption was 770 million gallons; by 2012 the annual water consumption for hydro-fracking had shot up to 4.27 billion gallons per year.

    Over the same four year period, the number of newly drilled oil wells increased more than fourfold, rising from 401 in 2008 to 1801 in 2012. Hydraulic fracturing (or hydro-fracking) — a technique commonly used for oil extraction in shale formations — involves pumping large volumes of water into the wellbore under pressure to fracture the shale rock deep under ground, which releases the natural gas and oil locked within. However, the expansion of oil wells is not the only reason for increased water consumption as a result of oil development in the region.

    The study, titled "Water Use and Management in the Bakken Shale Oil Play in North Dakota," notes that due to the unusually high salinity levels found in this formation, well operators need to conduct routine maintenance flushing of 10-15% of the wells in North Dakota's Bakken region to prevent build-up of natural salts. The use of this additional maintenance water is apparently unique to wells within the Bakken shale deposit.

    Typically, within the Bakken shale deposit, the frequency of maintenance flushing tends to increase the further west wells are located. Although the publicly available data of water usage for maintenance flushing is limited, the study estimates that this ranges between 400-1400 gallons per day per well that requires flushing.

    Wastewater production from fracking operations is also higher in the Bakken shale than other deposits, and has risen from 1.1 million gallons for wells drilled in 2008 to 2.9 million gallons for those drilled in 2012, with most of this water being supplied by Lake Sakakawea. Yet, while the increase in water use from the lake as a result of oil development and associated population growth does not currently pose an issue in terms of continued water availability, Clark points out that by studying the impact that the expansion of the oil industry has on water usage in the Bakken region may assist with determining the impact in other shale deposits.

    "While no other play may have experienced an increase in local population as proportionally large and easy to define as the Bakken, temporary oilfield service populations have an impact everywhere," according to the study. "More data collection and further study in the Bakken and elsewhere are needed to better understand, quantify and minimize water impacts of unconventional oil and gas development in the future."

    Journal Reference

    R. M. Horner, C. B. Harto, R. B. Jackson, E. R. Lowry, A. R. Brandt, T. W. Yeskoo, D. J. Murphy, and C. E. Clark. Water Use and Management in the Bakken Shale Oil Play in North Dakota. Environmental Science & Technology 2016 50 (6), 3275-3282. DOI: 10.1021/acs.est.5b04079
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  • Groundwater Contamination: When Water's Not Fit to Drink

    Contamination of groundwater sources poses serious consequences in the future, especially in light of increasing droughts, which is placing more pressure on dwindling water resources that we direly need to protect at all costs. A recent report titled 'Alternatives for Managing the Nation's Complex Contaminated Groundwater Sites', commissioned by the National Research Council, revealed that groundwater at more than 126,000 sites around the U.S. is contaminated.  These sites are all in need of remediation, with 10% of the contaminated sites being classified as ''complex'', and which were unlikely to be remediated for at least another 50 to 100 years.

    The estimated cost of remediating these contaminated sites is over $110 billion, according to the report, and does not take technical problems associated with rehabilitation of ''complex'' sites into account, or the rehabilitation of groundwater at sites that may become contaminated in the future.

    The U.S. Government has initiated a series of groundwater cleanup programs at both state and national level focusing on reducing the environmental and health risks associated with groundwater contamination. Some of the areas that have been addressed include cleanup of Superfund sites; environmental remediation of sites where hazardous waste is stored, treated, or disposed of; remediation of areas contaminated by leaks from damaged underground storage tanks; as well as remediation of government and military facilities, and industrial operations.

    credit: Ryan Griffis - credit: Ryan Griffis -

    It is estimated that about 3.4% of the active cleanup sites are sites that fall under the jurisdiction of the U.S. Department of Defense, who have already spent $30 billion to remediate their sites of hazardous waste. However, many of their sites pose the highest challenges both in terms of technology needed and costs associated with successful cleanup operations and remediation efforts.

    "The complete removal of contaminants from groundwater at possibly thousands of complex sites in the U.S. is unlikely, and no technology innovations appear in the near time horizon that could overcome the challenges of restoring contaminated groundwater to drinking water standards," said Michael Kavanaugh, from Geosyntec Consultants, Inc. and chair of the committee that produced the report. "At many of these complex sites, a point of diminishing returns will often occur as contaminants in groundwater remain stalled at levels above drinking water standards despite continued active remedial efforts. We are recommending a formal evaluation be made at the appropriate time in the life cycle of a site to decide whether to transition the sites to active or passive long-term management."

    Taxpayers will foot a large portion of the cleanup bill, as many of the sites that are considered ''complex'' are on public land, or fall under the jurisdiction of government agencies.
    The terminology used in cleanup operations is often misleading, as very often closed sites still have levels of contamination that require monitoring and management well into the future, as well as funding to do so. Half of the Superfund sites that have been removed from the list still require ongoing monitoring, evaluation and management of contaminated groundwater according to the report, which recommends that the different phases in the cleanup process together with progress reports should be clearly defined to increase public and stakeholder awareness.

    According to Kavanaugh:

    "The central theme of this report is how the nation should deal with those sites where residual contamination will remain above levels needed to achieve restoration. In the opinion of the committee, this finding needs to inform decision making at these complex sites, including a more comprehensive use of risk assessment methods, and support for a national research and development program that leads to innovative tools to ensure protectiveness where residual contamination persists. In all cases, the final end state of these sites has to be protective of human health and the environment consistent with the existing legal framework, but a more rapid transition will reduce life-cycle costs. Some residual contamination will persist at these sites and future national strategies need to account for this fact."

    In the event of a major storm or natural disaster, this can lead to further problems. For example, in the wake of Hurricane Sandy affected residents were not only exposed to flaking paint from damaged homes, putting them and especially their children at risk of lead poisoning; lead dust from contaminated Superfund sites was washed off site by storm surge or blown off site by strong winds. When disturbed, these highly toxic contaminants pose a risk wherever they settle, both on the soil surface, and to groundwater sources below the soil. This clearly illustrates the importance of remediating contaminated sites to prevent the contaminants from migrating offsite, where they are far more difficult, if not impossible, to manage.

    If you know or suspect your are being exposed to such water, a system like a Berkey water filter can filter out contaminants from these affected sources.

    Further Reading:
    National Research Council. Alternatives for Managing the Nation's Complex Contaminated Groundwater Sites. Washington, DC: The National Academies Press, 2013. doi:10.17226/14668.

  • 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.

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    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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