EVALUATION OF ENVIRONMENTAL RISK OF HEAVY METALS IN THE SUPERFICIAL SEDIMENTS OF THE SACO DEL GOLFO DE CARIACO

The aim of this study was to assess the potential risk of heavy metals to the ecosystem of the gulf of Cariaco. To this end. we determined the concentration of heavy metals and the contamination and environmental risk indices in sediments. In addition, a survival test with Artemia salina was applied. The total metal concentrations (mu g/g) were: Cu (29-91, (X) over bar = 58), Cd (1.9-4.9,(X) over bar= 3.7), Cr (4-36, (X) over bar = 21), Ni (10-33, (X) over bar =21), Pb (3-9, (X) over bar = 6) and Zn (32-112, (X) over bar = 75). Metal concentrations were lower than the sediment quality standards (SQS). In the bioavailable fraction of sediments, the concentration of metals was innocuous. The enrichment factor (EF) showed that Zn. Cd and Cu were enriched by anthropogenic sources. The geoaccumulation index (Igeo) revealed high contamination by Cd. The risk assessment code (RAC) showed that the concentrations of Cd and Cr were innocuous, Cu and Ni were between harmless and scarecely dangerous, and Zn and Mn were moderately hazardous. Finally, Cd, Cu and Ni were the only metals with concentrations ranging between effects range low (ERL) and median (ERM) and the combined toxic potential of the metals was low (21%). Despite this, no specimen of Artemia salina had negative effects on sedimentary extracts. Therefore, the ecosystem can be considered healthy, which is favored by very fine and anoxic sediments that lead to accumulation of metals.