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(W/FF223) Toxicity and metalic content in the sediments of Cadiz Bay (Spain). Morillo, José1, Usero, José1, Gracia, Ignacio1, 1 ABSTRACT- Cadiz Bay is a 10-km-wide inlet located in the southwest of the Spanish Atlantic coast. This bay receives large amounts of pollutant waste such as the residual waters of highly-populated cities (Rota, El Puerto de Santa Maria, Puerto Real, San Fernando and Cadiz) and the industrial effluents from companies that use large quantities of metal (shipbuilders, automobile parts manufacturers, etc.) and producers of goods for consumption (the alcohol industry, the tobacco industry, etc.). Moreover, the Guadalete River, which receives the residual waters from highly-populated areas and several industrial waste sites, empties into this bay. In this study 10 sediment samples were taken in Cadiz Bay and were analysed for the content of 9 metals (Cr, Ni, Mn, Cu, Cd, Pb, As, Hg y Zn); the toxicity was also determined. To determine the toxicity, a new toxicity test method placing the luminescent bacteria Photobacterium phosphoreum in direct contact with the sediments was used. Suspensions of sediments in water were tested in direct contact with the luminescent bacteria followed by separation of sediment particles from the bacteria prior to light intensity measurements. The results showed that there are high correlation coefficients among the toxicity levels and the amount of metal of the sediments. The greatest amounts of toxicity and contamination by metals were obtained in the internal area of the bay, mainly because in this area there is a low rate of renovation of the waters, which favours the accumulation of pollutants. Key words: sediment, toxicity, metallic content |
