LOGAN, UTAH – In the United States, pesticide use results in widespread dispersal of chemical contaminants that pose risks to environmental and human health. While the U.S. Environmental Protection Agency evaluates risk through a nationwide process, Utah State University ecotoxicologist Lorin Neuman-Lee argues the assessments rely on pesticide industry-supplied studies that may produce insufficient, biased results.
“We need more balanced representation in evaluating risk,” says Neuman-Lee, a doctoral candidate in USU’s Department of Biology. “We need to start a conversation about conflicts of interest that impede assessment of chemicals and practices that affect all Americans and our environment.”
The USU researcher is among 15 authors of a commentary published in the Sept. 3, 2014, issue of “BioScience,” outlining limitations of current policy and recommending improvements. In the paper, the researchers use the EPA’s recent reassessment of the widely used herbicide atrazine and its effects on amphibians as an example of shortcomings with the current evaluation system.
Neuman-Lee has long studied the effects of atrazine, an agent commonly used to control weeds in cornfields, golf courses and lawns, on amphibians. Banned in Europe, the herbicide is an endocrine disruptor, which alters hormonal processes in many animal species.
“An often observed finding in amphibians exposed to atrazine is hermaphroditism – that is, the presence of both male and female sex organs,” she says.
The herbicide is one of the most commonly detected pesticides in the nation’s drinking water, yet the EPA maintains presence of the agent remains at acceptably safe levels.
“Our team is concerned about the prevalence of atrazine in the environment,” Neuman-Lee says. “The herbicide degrades slowly and the EPA’s assessment may not tell the whole story.”
Organisms exposed to atrazine may suffer more damage at low doses than higher exposures.
“While this seems counterintuitive, low levels of these hormone-mimicking chemicals can cause changes in the body without triggering mechanisms that would normally regulate an excess of hormones,” she says.
In a two-year study of turtles exposed to atrazine from Iowa cornfields, Neuman-Lee noted individuals receiving the lowest doses of the agent had the lowest rates of survival. She noted similar findings with snakes.
“To effectively evaluate an agent, you have to look at its effects on the whole organism in the whole ecosystem,” she says. “Risk assessments should be based on sound research and management decisions should be made with objectivity. As long as industry influences the process, you have a potential ‘fox watching the hen house’ situation.”