Relationships between Heavy Metal Concentrations in the American Oyster (Crassostrea virginica) and Metal Levels in the Water Column and Sediment in Apalachicola Bay, Florida

This study aims to assess baseline concentrations of heavy metals (Cd, Cr, Cu, Pb and Zn) in the oyster soft tissue as they relate to concentrations in the water column (particulate phase) and sediment in Apalachicola Bay. In order to conduct these assessments, a total of 360 samples, collected in two seasons (winter and summer) and were analyzed using atomic absorption spectrometry. Results indicated that elemental concentrations in particulate phase correlate significantly with concentration in the tissue than those in the sediment. Moreover, assessment of seasonal and spatial variations have indicated that oysters collected in the winter have significantly higher (P<0.05) Cu, Pb and Zn concentrations than oysters collected in the summer. However, metal concentrations in sediment did not show such patterns. These observations confirmed the fact that metals in the particulate phase are more bioavailable to oysters and that the oysters can be used as good indicators of the spatial and temporal variation of the heavy metals in the aquatic system.