Variation Of Mercury Concentration in Fish Taken from Lake Boeuf, Southeastern Louisiana

Abstract

The concentration of mercury was measured in a variety of fish and sediment cores taken from Lake Boeuf located in southeastern Louisiana. Lake Boeuf is an important recreational and game fishing lake from which the following sunfish are caught and consumed: bluegill sunfish (Lepomis macrochirus), redear sunfish (Lepomis microlophus), largemouth bass (Micropterus salmoides), and black crappie (Poxomis nigromaculatus). These species of fish were collected and mercury levels were determined using the EPA cold vapor analysis method 7471. Mercury concentrations exceeding the FDA action level of 1.0 μg/g in fish were found in 4 of 15 bluegill sunfish and 2 of 15 black crappie. Bluegill sunfish contained the highest concentrations of mercury, ranging in value from <0.02 to 0.92 μg/g and an average of 0.22±0.31 μg/g. Redear sunfish had the lowest concentration, averaging only 0.03±0.03 μg/g. Sediment cores revealed a history of mercury inputs to the lake with concentrations as high as 0.25 μg/g at depths of about 15 cm.