Heavy metal concentrations of the soldier crab (Mictyris brevidactylus) along the inshore area of Changhua, Taiwan

In order to compare with and assess the metal-accumulating ability of the soldier crab (Mictyris brevidactylus), the concentrations of copper (Cu), zinc (Zn), nickel (Ni), lead (Pb) and cadmium of ambient water and the Pacific oyster (Crassostrea gigas) were investigated. Seawater, soldier crabs and Pacific oysters were simultaneously collected from the Changhua coastal area, located in West-Central Taiwan. The Pacific oyster and stream results proved that site B is contaminated by Cu, Zn and Pb from streams B-1 and B-2. The highest Cu, Zn, Ni and Pb concentrations in soldier crabs appeared at site B, and significant differences in the accumulated concentrations of Cu, Pb, Zn and Ni in soldier crabs were found between the sites tested. The highest bioconcentration factors of Cu, Zn, Ni and Pb in soldier crabs appeared at site B, indicating that the soldier crab can accumulate Cu, Zn and Pb to the same degree as the Pacific oyster. In fact, soldier crabs can accumulate more Ni than Pacific oysters, better reflecting the conditions of the ambient environment. These phenomena, as well as the fact that the soldier crab is able to accumulate relatively high levels of Cu, Zn, Pb and Ni, suggest that this crab is a potential biomonitor of Pb and Ni pollution in aquatic ecosystems.