Tyrone Hayes, PhD, Integrative Biology, University California Berkeley, Department of Integrative Biology, 3060 Valley Life Sciences Building #3140, Berkeley, CA 94720-3140, (510) 643-1054, tyrone@socrates.berkeley.edu

Atrazine is the most commonly used herbicide in the world. As a result, it is the most common contaminant of ground and surface water. Research from laboratory studies showed that atrazine demasculinizes and feminizes exposed male amphibians. The proposed mechanism of action, now confirmed by two laboratories, is the induction of aromatase expression. Aromatase is the enzyme that converts androgens to estrogens and explains both the demasculinization (loss of androgens) and feminization (inappropriate production of estrogens) in male amphibians. Furthermore, the proposed mechanism has been documented in fish, amphibians, reptiles, birds and mammals (all but one vertebrate class, which has not been examined). However, the Environmental Protection Agency, through its use of a "weight of the evidence" model, has afforded the herbicide industry the opportunity to dilute the evidence that atrazine disrupts the endocrine system. This presentation will present the science on atrazine and discuss the response of both industry and EPA to this latest science.

Learning Objectives:

• Understand the influence of the herbicide industry on scientific research of endocrine disrupters.
• Discuss the current EPA “weight of evidence model” that provides no incentive for industry to conduct appropriate studies on the safety of herbicide compounds.

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.