EPA to examine herbicides effects on human health

Oct 9, 2009
by DTN
EPA to examine herbicide’s effects on human health

A new study of atrazine’s effects on human health will begin this fall, with most of the review occurring in 2010, the Environmental Protection Agency (EPA) announced last Wednesday. It is unlikely changes in the atrazine label would affect the 2010 spring application season.

“We can, of course, ask registrants to make label changes at any time if an issue arises,” Steven Bradbury, deputy director of the Office of Pesticide Programs within EPA, told DTN. The first scientific reviews of new health studies, however, are scheduled to begin in February and April and typically take 60 to 90 days after that for a final report to occur. Precluding any information that raised immediate concern, those reports would come well after the heavy atrazine application season.

In a press release, the agency said it would be looking at recent studies on atrazine and its potential association with cancer, birth defects and other non-cancer health issues. It will especially be focusing on human health studies that havebeen conducted since 2003 when EPA finished its last review of the triazine herbicides, which include atrazine, simazine and propazine. In 2006, the agency said levels of triazines in the environment were “below the regulatory level of concern.”

“We don’t expect anything to happen with the regulation of atrazine whatsoever because the thorough review in 2006 and the existing knowledge we have would support the continued registration and label we currently have,” said Tim Pastoor, principal scientist with Syngenta, the primary manufacturer of atrazine. He said the announcement of this current review was not a surprise.

“The whole nature of EPA’s review is certainly a part of the regulatory process, so there’s nothing surprising there,” Pastoor said. “We’re prepared and ready for the series of scientific advisory panel meetings in 2010.” Pastoor pointed out that there have been nearly 6,000 studies on atrazine leading up to the latest registration and relabeling in 2006.

Bradbury said the review was being called to look at studies that have occurred since the 2006 relabeling and to review previous studies “in the context of new information.” He also is anticipating “a significant body of information” relating to pesticides and farm worker health in an update from the National Cancer Institute. That institute has an ongoing program, the Agricultural Health Study, that is examining potential relationships between pesticides and health issues among farmers, applicators and other farm workers.

In 2008, the cancer institute announced a relationship between two insecticides—chlorpyrifos and aldicarb (Temik)—and the risk of pesticide workers developing rectal or colon cancer.

Research on that tie is ongoing.

Syngenta has said in statements that about 60 percent of corn and 90 percent of grain sorghum is treated with atrazine. Use of the product, mainly as a premix with other herbicides, has climbed in recent seasons as farmers battle weeds resistant to glyphosate. The company said its water studies have shown that as atrazine use has gone up, atrazine concentrations in drinking water have dropped.

The first EPA meeting on the atrazine issue is scheduled for Nov. 3, in which the agency will discuss basic information and create a plan for the evaluation process with its scientific advisory panel (SAP) made up of independent scientists. A SAP review of new human population, or epidemiological, studies is planned for February 2010 with a review of lab animal studies in April.

By September, Bradbury said, EPA will present a full peer review of the atrazine studies to the advisory panel. By the end of 2010, that SAP group will report on whether atrazine is considered safe as labeled or whether changes in its registration should be considered.

Steve Owens, assistant administrator for EPA’s Office of Prevention, Pesticides and Toxic Substances, said in the agency release that, “Our examination of atrazine will be based on transparency and sound science, including independent scientific peer review, and will help determine whether a change in EPA’s regulatory position on this pesticide is appropriate.” — DTN