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Herbicide Poses No Cancer Risk In Drinking Water

Over the years, the Environmental Working Group (EWG) and the Natural Resources Defense Council (NRDC) have repeatedly issued bogus reports claiming that Americans face serious cancer risks from trace chemicals found in drinking water. A new study challenges their claims regarding one of these activists’ key targets: the herbicide atrazine, which farmers use to control weeds rather than tilling the soil.

This study, published in the European Journal of Cancer Prevention, underscores why we need not fear atrazine or listen the green hype. It employed a “weight-of-the-evidence” test for assessing safety of this chemical, which examines the full body of research on a topic and then emphasizes the best quality research to draw conclusions. Such weigh-of-the-evidence tests provide much better information than cherry-picking studies -- as the NRDC and EWG usually do -- to support predetermined, politically driven positions.

The study authors report:

The aim of this study was to evaluate the conflicting reports from the Environmental Protection Agency and the Scientific Advisory Panel (Panel) on the carcinogenicity of atrazine in order to determine whether the results from epidemiologic studies support a causal relationship between atrazine and any specific cancer. We reviewed the Environmental Protection Agency and Panel reports in the context of all the epidemiologic studies on the specific cancers of interest. A weight-of-evidence approach leads to the conclusion that there is no causal association between atrazine and cancer and that occasional positive results can be attributed to bias or chance. Atrazine appears to be a good candidate for a category of herbicides with a probable absence of cancer risk. Atrazine should be treated for regulatory and public health purposes as an agent unlikely to pose a cancer risk to humans.

These findings are not surprising since America’s drinking water is not a likely source of cancer risks from atrazine or any other trace chemical. In their landmark study on the causes of cancer, scientists Richard Doll and Richard Peto noted that “with the possible exception of asbestos in a few water supplies, we know of no established human carcinogen that is ever present in sufficient quantities in large U.S. water supplies to account for any material percentage of the total risk of cancer.”

In addition to ignoring any such findings on safety, environmental activists simply refuse to consider benefits associated with chemicals, particularly pesticides. For example, the NRDC says “atrazine provides little benefits to offset its risks.” But this claim flies in the face of considerable evidence to the contrary.

Before the 1960s and the use of herbicides like atrazine, farmers relied on tilling the soil to control weeds, a practice that led to sediment runoff into nearby waters. Such sediment blocked sunlight out of streams and waterways, killed vegetation, and harmed wildlife. “Many environmental scientists agree,” researcher Allan Felsot explains, “that eutrophication and sedimentation of aquatic resources due to runoff and erosion from agricultural land is the most important cause of water quality impairment, not to mention being responsible for transportation problems as rivers backfill with sediment.”

The answer to this problem came from no-till and conservation tillage (reduced tilling) for farming, a practice made possible by chemical herbicides like atrazine. The use of herbicides reduces soil erosion by 50 to 98 percent, notes Dennis Avery in True State of the Planet. Felsot notes that soil erosion resulting from tilling in Illinois, Indiana, Iowa, and Nebraska amounted to 14.9 tons per acre each year, whereas no-till farms there released only 0.8 tons per acre annually.

Researcher Paul D. Mitchell of the University of Wisconsin agrees:

Atrazine and the other atriazine herbicides have contributed to the observed decrease in soil erosion by providing an effective residual herbicide for weed control in conservation tillage and no-till systems. If triazine herbicides were not available to U.S. farmers, this analysis shows that aggregate soil erosion from U.S. cropland would begin to increase and reverse the tremendous advances in soil management that U.S. farmers have made in the last 30 years to reduce soil erosion.

Atrazine and similar herbicides also benefit wildlife as well by increasing productivity per acre, leaving more land for wildlife.  Dvid C. Bridges, Ph.D., president of the University of Georgia’s Abraham Baldwin Agricultural College, notes: “It’s hard to overestimate the importance of atrazine and the triazine herbicides to U.S. agriculture and global food supplies. They benefit food production, the environment and the economy—and that means jobs… Some say there are ready replacements. In fact, there is no substitute for atrazine.” According to Bridges, atrazine increases corn production by seven bushels per acre, and sorghum farmers gain an additional 13 bushels per acre.

Researcher Richard S. Fawcett highlights the impacts of such efficient, high-yield farming: “We do know that wildlife habitat has been greatly improved. Conservation tillage created habitat, benefits ecology …When I was a kid, you would never see wildlife on a farm, but today you do. The wildlife is back.”

These are benefits that environmentalists should appreciate, if only they could get past their ideology to see the facts.