Cadmium, lead and zinc concentrations in water, sediment and oyster (Crassostrea virginica) of San Andres Lagoon, Mexico.

The spatial distribution of cadmium, lead and zinc concentrations in water, sediment and oysters from San Andres Lagoon was evaluated. Significantly higher cadmium (0.33 mg L(-1)) and lead (0.70 mg L(-1)) concentrations in water were observed in front of the mouth of Tigre river, whereas, zinc concentration (5.0 mg L(-1)) was significantly higher in the south part of the lagoon. Similarly, lead and zinc values in sediment (1.01 and 9.29 μg g(-1), respectively) and oyster tissue (0.86 and 3.19 μg g(-1), respectively) were significantly higher in the south part of the lagoon. Levels of cadmium and lead in oyster tissue were positively related to those found in sediment. However, concerning zinc no evident relationship was found. Such differences in regression analyses may be explained by differential bioaccumulation of xenobiotic (cadmium, lead) and essential (zinc) metals.