(Beyond Pesticides, June 8, 2016) With years of data documenting the harmful impacts of the herbicide atrazine on aquatic organisms and other wildlife, a recent U.S. Environmental Protection Agency (EPA) assessment now concludes that this widely used chemical poses risks to fish, amphibians, aquatic invertebrates, and even birds, reptiles and mammals. Atrazine is a potent endocrine disruptor with strong associations with birth defects, sex reversal and hermaphroditism in organisms, and whose risk to environmental and human health is exacerbated by pervasive surface, ground and drinking water contamination.
Last week, EPA released its triazine ecological risk assessments for atrazine and its chemical cousins simazine, and propazine. The assessments evaluated risks to animals and plants including, amphibians, birds, mammals, fish, reptiles, aquatic invertebrates, aquatic plant communities, and terrestrial plants. EPA is currently in the registration review process for these chemicals. For atrazine, EPA concludes, “aquatic plant communities are impacted in many areas where atrazine use is heaviest, and there is potential chronic risks to fish, amphibians, and aquatic invertebrate in these same locations. In the terrestrial environment, there are risk concerns for mammals, birds, reptiles, plants and plant communities across the country for many of the atrazine uses.” Levels of concerns were exceeded by as much as 200-fold for some organisms! When it comes to amphibians, impacts which have been extensively documented by researchers like Tyrone Hayes, PhD, at the University of California, Berkeley, EPA finds that “there is potential for chronic risks to amphibians based on multiple effects endpoint concentrations compared to measured and predicted surface water concentrations.” Previous scientific reviews, like the 2009 analysis of more than 100 scientific studies conducted on atrazine, found evidence that atrazine harms fish and frogs.
The results are similar for simazine and propazine, since all three triazines show similar effects at similar concentrations. Simazine, which is frequently detected in surface and groundwaters, was found to have potential chronic risks to mammals and birds. Simazine spray drift and runoff can also impact non-target plants. For propazine, which has minimal uses (preemergent control in sorghum and container grown ornamentals in greenhouses only), the agency identified chronic risks to mammals, birds and non-target plants. All three chemicals are mobile and persistent in the environment, which results in water contamination. According to the U.S. Geological Survey (USGS), atrazine is one of the most frequently detected pesticides, found at concentrations at or above aquatic benchmarks, and is also frequently detected in shallow ground water in agricultural areas, and in urban streams. Similarly, a 2009 report by the Natural Resource Defense Council (NRDC) “Poisoning the Well,” 97% of surface drinking water systems in Midwestern States show atrazine contamination. Atrazine’s manufacturer, Syngenta, reached a class action settlement in 2012 with water utilities across the country to clean up atrazine in drinking water supplies. This case, City of Greenville v. Syngenta Crop Protection, Inc., and Syngenta AG, Case No. 3:10-cv-00188- JPG-PMF, showed that atrazine contaminated community water systems’ raw and finished water. The lawsuit claimed that atrazine at any level injures water supply systems, and requested that Syngenta bear the cost of removing atrazine from water systems.
Since atrazine water contamination is so pervasive, risks to sensitive aquatic species are especially important. Specifically, EPA finds that atrazine chronic levels at or above 5ppb lead to reproductive effects in fish, while exposures to levels of 3.4ppb for 60 days or more can impact aquatic plants’ productivity, structure and function. The agency acknowledges that the observed impacts occur at levels below those that have been found through environmental monitoring, as well as at EPA’s safe drinking water standard (3ppb). Studies by Dr. Hayes and others have shown that concentrations as little as 0.1ppb impact hormone function in organisms and turns tadpoles into hermaphrodites – creatures with both male and female sexual characteristics. Research also finds that atrazine interferes with mammary gland development in the breast of mammals and is linked to certain birth defects like gastroschisis and choanal atresia, which are significantly increased for pregnant women with high levels of atrazine exposure.
EPA’s recent triazine assessments are not without challenge from industry groups that disagree with the findings and the studies EPA used to reach its conclusion. Industry groups still contend that atrazine is “safe” to use despite a wealth of scientific evidence from independent researchers which say otherwise. Atrazine is currently banned in the European Union over concerns of widespread water contamination. Environmental groups have long called for the U.S. to follow Europe and ban atrazine. A 2014 study published in the International Journal of Occupational and Environmental Health found that banning atrazine would result in net economic benefit to farmers. Given that over 70 million pounds of atrazine are used annually, the serious ecological impacts associated with its continued use, and the availability of alternatives, advocates argue that atrazine use must come to an end. View Dr. Hayes’ keynote talk on atrazine and endocrine disruption at Beyond Pesticides’ 33rd National Pesticide Forum in 2015.
EPA’s draft assessments are now open for public comment and will be followed later this year by an assessment of atrazine’s human health effects. EPA will have atrazine’s assessment peer reviewed by the Scientific Advisory Panel in 2017. Submit your comments for Atrazine (EPA-HQ-OPP-2013-0266), Simazine (EPA-HQ-OPP-2013-0251) and Propazine (EPA-HQ-OPP-2013-0250) by August 5, 2016.Source: EPA News Release
All unattributed positions and opinions in this piece are those of Beyond Pesticides.