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Science Cafe March 4: “From Silent Spring to Silent Night: a Tale of Toads and Men”

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Wednesday, March 4, 2015


Toads Amplexus
The herbicide, atrazine is a potent endocrine disrupter that chemically castrates and feminizes exposed male amphibians. Further, atrazine exposure results in neural damage and hyperactivity and induces a hormonal stress response that leads to retarded growth and development, and immune suppression. The immune suppression results in increased disease rates and mortality. Though many factors likely contribute to amphibian declines, pesticides (such as atrazine) likely play an important role even in populations that appear to decline for other reasons, such as disease. Pesticides like atrazine are ubiquitous, persistent contaminants and, though more pronounced in amphibians, the effects described above occur in all vertebrate classes (fish, amphibians, reptiles, and mammals) examined, via common mechanisms. These observations demonstrate the critical impact that pesticides have on environmental health.Reproductive cancers and birth defects associated with exposure to many of these chemicals (e.g. atrazine) via identical mechanisms demonstrate that the impact on environmental health is an indicator of a negative impact on public health. Many of these mechanisms are being revealed only now in the scientific literature and agencies are just now beginning to deal with this emergent science and translate it efficiently into health-protective policies. In particular, ethnic minorities and lower socio-economic communities are at risk: More likely to live in contaminated communities, work in occupations that increase hazard exposure and less likely to have educational and healthcare access. Given the importance of this science and relevance to public health, there is a strong need to translate this information and provide public access to this knowledge. Command of the science and active involvement by the public in policy decisions is vital. Accurate information and public dissemination is especially important in light of evidence showing the manufacturer’s attempts to cover up information and discredit scientists.
Tyrone Hayes Tyrone B. Hayes is a biologist and professor of Integrative Biology at University of California, Berkeley known for his research findings concluding that the herbicide atrazine is an endocrine disruptor that demasculinizes and feminizes male frogs. Currently, he is also examining the effects of exogenous steroids on gonadal differentiation and the potential role of endogenous steroids.


East Bay Science Cafe is held the first Wednesday of every month in Cafe Valparaiso on Solano Avenue in Albany from 7 to 9pm. 1403 Solano Ave., Albany, California 94706
This cafe is an informal forum for discussing interesting and relevant scientific issues. The goal is to encourage public engagement with science by inviting members of the scientific community to present topics for a casual evening of conversation. Cafes may vary in length and format depending upon the speaker and the topic. Audience questions are encouraged both during and after!
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