Pearl River Estuary (PRE) is the largest estuary in Southern China and there has been
an increasing concern of metal pollution due to regional industrialization. In this
study, we investigated the spatial variation of metal pollution (Ag, As, Cd, Cu, Pb,
and Zn) as well as their subcellular handling in the oyster Crassostrea hongkongensis.
Hot spots of metal contamination in the oysters were found in different sites, suggesting
that there were different sources of metals in the estuary associated with industrial
activity. Metals differed in their subcellular bindings in the oysters from different
locations. Metal distribution in the biologically detoxified fraction decreased for
Cu but increased for Zn with increasing contamination in the oysters. For Zn, there
was a significant difference in its two detoxification pools (metal-rich granules
and metallothionein-like proteins) in response to Zn contamination. The high Cd concentrations
in oysters may carry a high Cd hazard to the consumers.