Mercury Concentrations In Blue Sucker and Freshwater Drum

Mercury (Hg) concentrations were determined in Blue Sucker (Cycleptus elongates) and Freshwater Drum (Aplodinotus grunniens) collected from the Green River. Highest Hg levels were found in the Freshwater Drum with an overall maximum of 980ppb. The amount considered by the Food & Drug Administration (FDA) to be potentially harmful for human ingestion is 1000ppb. Samples collected from different sites along the river show no significant variations in Hg levels between similar fish types. Females of both types contained higher Hg levels than males, and as the fish weight increased, the mercury amount also increased. Liver and tissue Hg concentrations in Freshwater Drum were significantly greater than that of Blue Sucker. The mean Hg concentrations were all lower than the FDA's maximum allowable concentration. However, bioaccumulation of Hg does obviously occur. Data from the EPA's toxic release inventory reflects the release of mercury into the environment, including near the Green River, by Kentucky industries. This research establishes a baseline of Hg concentration in Green River fish, leading to a better understanding of future impacts from mercury in the environment.