Environmental chemist Martha Wells is conducting ongoing research to assess the occurrence of chemicals causing endocrine disruption in fish in the South Branch of the Potomac River. The objective of the research is to ascertain the chemical(s) that are implicated in the endocrine disruption of the reproductive function in fishes, particularly smallmouth bass, collected from sites located within the South Branch of the Potomac River drainage. In this project, eight fish (male, smallmouth bass) were analyzed for total mercury, methyl mercury, and barium content. Research like this is becoming increasingly important as EDCs and pharmaceuticals and personal care products (PPCPs) are receiving growing attention from the scientific community, regulatory agencies and the general public. Results of several recent studies indicate that the discharge of wastewaters and agricultural runoff into the environment yields a large number of these compounds. Public interest in this issue continues to increase, and the U.S. Environmental Protection Agency has been mandated to conduct a screening program for them. According to a research paper by the EPA's National Exposure Research Laboratory, the immediate environmental effect of the PPCPs is hard to determine, but their presence in water over long periods can be detrimental.