PH18 Assessing Human/Environment Interactions
Exhibit Hall
8:00 AM - Thursday
(PH209) Effects of atrazine, metolachlor and diazinon alone or in binary mixtures on human fibroblast proliferation.
Clayton, M1, Dhanwada, K1, Deng, Y1, 1 University of Northern Iowa, Cedar Falls, IA, USA
ABSTRACT- The frequent and heavy use of pesticides in agriculture has led to the contamination of surface and ground waters worldwide. Many questions have arisen about the human health effects of exposure to these pesticides and their mixtures. Cell proliferation assays were performed with normal human fibroblasts to test the toxicity of environmentally relevant levels of three of the most heavily used pesticides in the United States: atrazine, metolachlor and diazinon, either alone or in binary mixtures with atrazine. MTT analysis showed a statistically significant decrease in cell proliferation compared to the control at low levels of each of the three single pesticides tested (≥ 0.8 ppb atrazine, ≥ 1.6 ppb metolachlor and ≥ 1.6 ppb diazinon) as well as with binary mixtures of either atrazine and metolachlor or atrazine and diazinon. When experimental results were compared to predictions of toxicity based on the response addition model, the mixture of atrazine and metolachlor was shown to generally be antagonistic, while the mixture of atrazine and diazinon resulted in additive responses. These findings, along with other studies, indicate that current regulatory standards for pesticides in drinking water may not sufficiently protect human health.
Key words: metolachlor, atrazine, diazinon, mixtures