Bioaccumulation of trace metals in two oyster species from southwest Puerto Rico

As coastal ecosystems are impacted by land use change and anthropogenic activities, oysters can be an important tool for monitoring local water quality. We collected oysters (Crassostrea rhizophorae and Isognomon alatus) from coastal sites near Guánica and La Parguera in southwest Puerto Rico and analyzed their tissue for concentrations of Ag, As, Cd, Co, Cr, Cu, Ni, Pb, V, and Zn. All trace metals were found in both species, with high bioaccumulation factors for Ag, Cd, and Zn in both species and Cr in C. rhizophorae. Some trace metals are likely associated with anthropogenic sources, including paints and vehicles (Cu and Zn), oil (Ni and V), and wood preservatives (As). Cr in oysters near Guánica is most likely associated with sediment from erosion in the watershed. Both species could be used to monitor changes in trace metal concentrations and the influence of future watershed management strategies in the region.