Transplanted aquatic mosses and freshwater mussels to investigate the trace metal contamination in the rivers Meurthe and Plaine, France.

Aquatic mosses Cinclidotus nigricans and freshwater mussels Dreissena polymorpha were transferred at eight monitoring sites along the rivers Meurthe and Plaine (northeastern France) for a biological assessment of the trace metal contamination. Autochthonous Fontinalis antipyretica mosses were collected at the end of the experiment. The major contaminants detected in the organisms were Cr, Ni, Pb and Zn. A comparison between the native and the introduced bryophytes showed that the transfer technique was preferable to assess the recent pollution situation. In the case of the transplanted mosses, high initial levels of strongly bound Pb and Zn prevented an accurate assessment of the contamination with these two metals, since only little depuration occurred at unpolluted sites. A good qualitative agreement was observed between the indications obtained from the mosses and those obtained from the mussels, suggesting that both are suitable indicators for monitoring purposes. The observed quantitative disparities were attributed to inherent differences in the accumulation strategies of each sentinel organism. Due to specific uptake and depuration kinetics, mosses and mussels appeared to be complementary in the detection of various types of pollution.