Monitoring Hg and Cd Contamination Using Red Swamp Crayfish (Procambarus clarkii): Implications for Wetland Food Chain Contamination

Henriques, J. F.; Tavares, P. C.; Correia-dos-Santos, M. M.; Trancoso, M. A.; Santos-Reis, M.; Branquinho, C.

Monitoring Hg and Cd Contamination Using Red Swamp Crayfish (Procambarus clarkii): Implications for Wetland Food Chain Contamination

2014

Environmental pollution is one of the most serious causes of degradation of Mediterranean wetlands. Mercury (Hg) and cadmium (Cd) are of particular concern due to biomagnification. Here, we used red swamp crayfish (Procambarus clarkii) to monitor the spatial and temporal patterns of these two metals in a Portuguese rice field system. We sampled the crayfish in three different sites and three different time periods in the Sado River Basin (Portugal). We measured temperature, pH, total dissolved solids and conductivity in the water. Hg and Cd were measured in the crayfish abdominal muscle tissue and exoskeleton. In muscle, a spatial pattern was found for the accumulation of Cd while for Hg, only a temporal pattern emerged. The spatial pattern for Cd seemed to reflect the mining history of the sites, whereas the temporal pattern for Hg seemed related to the flooding of rice fields. We suggest that this flooding process increases Hg bioavailability.

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