BIOACCUMULATION OF COPPER IN THE TISSUES OF POTAMONAUTES-WARRENI (CALMAN) (CRUSTACEA, DECAPODA, BRANCHIURA), FROM INDUSTRIAL, MINE AND SEWAGE-POLLUTED FRESH-WATER ECOSYSTEMS

The copper concentration detected in the water and sediments of the Na talspruit River, Bronkhorstspruit River and Nooitgedacht Dam exceeded certain stated limits for the protection of aquatic life. Despite cons iderable individual variation, the general ranking of copper concentra tions in the various tissues was carapace < muscle < gonads < midgut g land < gills. Seasonal variation was detected in the bioaocumulation o f copper in crabs sampled from the Natalspruit River. However, this ph enomenon did not occur in crabs from the other two water bodies. A sig nificant increase in copper concentrations was detected with a decreas e in size, indicating that the size of the crabs is an important influ encing factor in the bioaccumulation of copper. It was also found that more copper accumulated in the ovary than in the testis per unit weig ht. The bioaccumulation factors (BF) calculated for the different tiss ues with respect to the water were highest in the gills and midgut gla nd (785,00 - 1257,50 and 432,00 - 1340,00, respectively). The BF with respect to the copper concentration in the sediments was comparatively low for all the tissues (<0,10 - 2,74). It appears that P. warreni is able to regulate the copper concentrations in its various tissues and is therefore not a suitable indicator of the presence of copper in th e aquatic environment.