Bioavailability of metals in sediments from Spanish estuaries using Carcinus maenas

Abstract

Intermoult female crabs (Carcinus maenas) were used to evaluate the bioavailability of metals in sediments from three Spanish estuaries. Animals were exposed to the different sediments per replicate in glass aquaria during 21 days. A chemical analysis of the sampling sites was performed to determine the degree and nature of contamination. Salinity, pH and dissolved oxygen were controlled throughout the laboratory exposure. On day 21, the concentrations of different metals (Cu, Zn, Pb, Hg and As) were analyzed in gill tissues and in sediments. The results showed that bioaccumulation of Zn (975.50 mg kg-1) in the organisms was associated with the enrichment of this metal in the Guadalquivir Estuary after the Aznalcóllar mining spill (April 1998), while bioaccumulation of Cu (548.90 mg kg-1) showed different trends that are associated with other sources of contamination, such as the chronic spill of acidic waters in Huelva Ria. Relationships were observed between metal content in sediments and metal content in gill tissues through the biota-sediment accumulation factor. This relationship validates the use of bioaccumulation measurements to evaluate the bioavailability of metals in contaminated sediments.