Evaluating metal toxicity in contaminated sediments in the South of Spain

Coastal zones are ecologically important areas subject to heavy anthropogenic pressures such as urbanization, fishing, commercial transports, as well as industrial and agriculture activities. In this context, Huelva, in the south of Spain, is a polluted area due to these reasons. In order to evaluate the consequences of anthropogenic impacts in the coastal area of Huelva, sediments from three different sites (Bay of Cádiz, Muelle de Capesa and Mazagòn) were assessed using an integrated model. This methodology integrates sediment physical-chemical parameters and biological responses in test organisms. Metal concentrations (Cr, Cu, Fe, Mn, Ni, Pb, Zn) and organic matter content were measured as physical-chemical parameters. Biological responses were assessed using three bioassays in two marine species: Mortality for Ampelisca brevicornis and Fertilization and Larval development for Paracentrotus lividus. The test organisms were exposed under two different routes of exposure (whole sediment or elutriate). Acute effects associated with the presence of metals (Cr, Cu, Fe, Mn, Ni, Pb, Zn) were observed and resulted correlated with the abnormal fertilization and larval development of echinoderms exposed to the sediments. The results here obtained were useful to confirm that the high level of metals contamination found in Huelva area, when compared to the control site (Bay of Cádiz), is likely to pose adverse effects on marine resident biota.