Selenium bioaccumulation in gonads of largemouth bass and bluegill from three power plant cooling reservoirs

Male and female largemouth bass (Micropterus salmoides, Lacepede) and bluegills (Lepomis macrochirus, Rafinesque) were collected from two power plant cooling reservoirs that received ash pond effluent (Hyco and Catfish Reservoirs, North Carolina) and one that did not (Lake Sangchris, Illinois). Bluegills were also collected from a city reservoir (Roxboro City Lake, North Carolina) that received no industrial effluent. Selenium residues were determined separately in the gonads and in the carcasses of all fish collected. Residues in both carcasses and gonads were significantly higher in fish from reservoirs receiving ash pond effluent. Ovarian selenium concentrations were greater than testicular levels, while concentrations in carcass did not differ between the sexes. Selenium concentrations were significantly higher in the ovaries than in the rest of the carcass in both largemouth bass and bluegills. In males, selenium levels declined in gonads relative to those in the carcass as selenium concentrations in the carcass increased, but no such pattern was evident in females. Bioaccumulation resulted in selenium concentrations 1,000 times higher in the ovaries of bluegills than in the water from which the fish were collected.