Of six bass extracts tested for estrogenic activity, four displayed a strong or moderate ability to bind with the estrogen receptors. Of 21 catfish extracts tested, nine displayed a similar ability to bind with the estrogen receptors. The researchers also examined whether the fish extracts could result in growth of breast cancer cells cultured in the laboratory, and they found that two bass extracts produced strong-to-moderate cell growth, as did five catfish extracts.
"We know that there are hundreds, even thousands, of chemicals in the environment that can have estrogenic activity," said Dr. Eagon. "These chemicals usually come from industrial pollution, farm animals, farm chemicals and municipal water treatment plants. What surprised us most in this study was that these estrogenic materials are present in such easily detected levels in local fish."
According to Dr. Volz, the next step in this research is to identify the estrogenic chemicals and their sources in the local water and fish. "These findings have significant public health implications, since we drink water from the rivers where the fish were caught. Additionally, the consumption of river-caught fish, especially by semi-subsistence anglers, may increase the risk for endocrine-mediated health endpoints like some cancers and developmental problems."