Metals in Waters and Sediments of the Morrocoy National Park, Venezuela: Increased Contamination Levels of Cadmium over Time
2011
García, E. M. | Bastidas, C. | Cruz-Motta, J. J. | Farina, O.
Concentrations of heavy metals in the western coast of Venezuela are partly driven by anthropogenic influences. To detect metal changes over time, the waters and sediments from 19 sites, across various marine ecosystems, were sampled seven times between 2000 and 2001 and compared with previous studies. The water samples had mean concentrations of Cd, Cu, Pb, and Zn above the guideline values proposed by NOAA as capable of producing chronic effects in the marine biota. In sediments, the mean Cd concentration also exceeded NOAA's Effects Range-Low values for all habitat types, and in sheltered sites, it exceeded NOAA's Effects Range-Median values. The meta-analysis indicated that metal concentrations in water were higher in 2000-2001 than in 1995-1997, with the exception of Pb. In sediments, however, only the concentrations of Cd, Cu, and Pb increased in this period. This increase was particularly noticeable for Cd which, by 2000-2001, showed Igeo values indicating that Morrocoy National Park could be considered strongly to extremely polluted. This increment in the metal concentrations could be associated with: (1) an anomalous precipitation event that occurred at the end of 1999 and which caused a disturbance in the sediment chemistry of most metals and/or (2) an increase in the anthropogenic and natural input of Cd probably associated with the production of fertilizers in the region during the period analyzed. Special attention should be paid to Cd levels in this area as it represents a high toxicological risk for the biota in different habitats.
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