Mercury levels in muscle of two fish species and sediments from the Cartagena Bay and the Cienaga Grande de Santa Marta, Colombia

Mercury (Hg) content in sediments and muscle from two fish species were det ermined in Cartagena Bay and Cit naga Grande de Santa Marta, an industriali zed bay and an unpolluted estuary in the Caribbean coast of Colombia. Sampl ing was conducted four times during March-November 1996, including both the dry and rainy seasons. Significant differences in Hg concentration were de tected both for fish and sediments between the two waterbodies. Hg values r anged from 94 to 10,293 mu g/kg dry weight (dw) in sediments from Cartagena Bay and between 20 and 109 mu g/kg dw in Cienaga Grande de Santa Marta. Hi ghest Hg concentrations were observed for the omnivorous species Eugerres p lumieri, and lowest concentrations were found in the detritivorous Mugil in cilis. High Hg concentrations in sediments of Cartagena Bay were detected i n front of the sewage discharge of an extinct chlor-alkali plant, with decr easing concentrations in stations far from the source. Our results suggest that Hg can be persistent in the sediments of previously exposed ecosystems and that the use of their biological resources should be avoided until dec ontamination programs guarantee safe levels of the metal in the environment . (C) 2000 Elsevier Science Ltd. All rights reserved.