THE IMPACT OF ENDOCRINE DISRUPTORS IN SUCKERMOUTH MINNOWS (Phenacobius mirabilis) REPRODUCTIVE TISSUES
Dexter, Shannon L.
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The presence of endocrine disrupting chemicals (EDCs) within aquatic environments continues to be a concern amongst biologists and conservationists. Substances used within hormonal contraceptives (Mestranol), veterinary pharmaceuticals (Progesterone), and pesticides (Atrazine) have been observed to interfere with hormone signaling genes that alter development of reproductive anatomy and function. Presence of these water soluble, and lipophilic, substances have been found within water effluents, and the concentration has been linked to feminization within aquatic organisms such as the Suckermouth minnow (Phenacobius mirabilis). The objective of this study is to determine if feminization is occurring within minnow testicular tissue. If observed, this would indicate high concentrations of EDCs within the water column, and would spark discussions about minimizing the input of EDCs into water systems. Minnows were collected at sites upstream and downstream from a water treatment facility adjacent to Post Oak Creek in Warrensburg, Missouri. Specimens were then dissected, and testicular tissues were analyzed by utilizing Hematoxylin and Eosin histological techniques to determine if EDCs are causing feminization. By the end of this study, no histological evidence was present, so gonadosomatic indices (GSI) were calculated and compared for the upstream and downstream sites. There was not any statistical significance with the GSI values, but there is a trend that should be noted for future projects.