Widespread contamination of US drinking water


A new report released by the Environmental Working Group (EWG) and Physicians for Social Responsibility (PSR) states that more than 14 million people in the USA routinely drink water that is contaminated with carcinogenic herbicides.

The report, entitled "Tap Water Blues", investigates the midwest, Louisiana and the Chesapeake Bay regions for contamination by five of the most commonly used herbicides in the United States (alachlor, metolachlor, atrazine, cyanizine and simazine). The study finds contamination, often by two or more of the herbicides, in the drinking water of all three regions.

At least 90% of all US municipal water treatment facilities lack the equipment to remove these chemicals.

The weed killers found at the highest levels in drinking water are known as the triazine herbicides. Laboratory studies have linked the herbicides with health problems including developmental abnormalities, birth defects, genetic mutations, breast cancer and cancers of the reproductive organs.

The Environmental Working Group and Physicians for Social Responsibility demand that the US Department of Agriculture and the US Environmental Protection Agency (EPA) phase out three of the most dangerous herbicides — atrazine, cyanizine and simazine — within two years.

Further, they urge that water utilities begin weekly monitoring of drinking water for all five herbicides during growing-season months (May-August), when farm chemical use peaks in these regions. Dr David Rall of PSR says, "Pregnant women and families with infants and young children would be prudent to drink bottled water during peak months until the government takes action to protect them".

Herbicide pollution is particularly extensive in the midwest, where corn and soybean growers apply about 70 million kilograms of the five herbicides annually. According to Richard Wiles of the Environmental Working Group, "The drinking water in nearly every midwestern city south of Chicago is contaminated with agricultural weed killers".

The report analyses tests on 20,000 samples taken from treated tap water and from rivers and reservoirs that are drinking water sources. The EWG and PSR argue that although the EPA has standards for allowable concentrations of herbicides in drinking water, they are inadequate for protecting the public from the herbicides examined in the joint report. In fact, there is no enforceable standard at all for cyanizine, the most toxic of the five.

According to the authors, the standards that do exist:

  • do not protect infants and young children, who drink more water per pound than adults and are more vulnerable because they are still growing;

  • do not consider the lifetime effects of drinking several chemicals combined in one water source;

  • do not account for the breakdown products of the herbicides, potentially hazardous chemicals that often increase through conventional water treatment;

  • ignore seasonal fluctuations in contamination, such as during summer months when agricultural run-off is at a peak.

Dr Rall notes the gravity of this situation in light of our ignorance of the connections between toxic chemicals and public health: "While scientists have long studied links between exposure to toxins and cancer, they have only recently begun to pay attention to endocrine, immune system, reproductive or developmental effects of toxins, especially on children".
[From Pesticide Action Network North America Updates Service.]