부산대학교 도서관

An investigation was made into the nickel concentrations of the water and sediments of the Natalspruit and Bronkhorstspruit Rivers (Gauteng) and Nooitgedacht Dam (North West Province), as well as nickel concentrations in tissues of the freshwater crab Potamonautes warreni from these three water systems. Water nickel concentrations were relatively constant, while large fluctuations were detected in the sediment nickel concentrations. The highest water and sediment nickel concentrations were measured at the Natalspruit River. The highest mean tissue concentration of nickel in P. warreni sampled from the three aquatic systems was detected in the carapace, indicating that this tissue might be used as a sink for nickel, for disposing of excessive amounts during the moult-cycle. No seasonal variation was detected. Sex also does not seem to be a variation factor in the bioaccumulation of nickel except in the mature gonads. P. warreni collected from the three different sampling sites showed a general increase in tissue nickel concentrations with a decrease in size. Significant correlations were observed between the midgut gland nickel concentrations and the concentration of this metal in the water (r=0,63) and sediment (r=0,77), as well as between the muscle nickel concentration and the water and sediment nickel concentrations (r=0,63 and r=0,77, respectively). These phenomena, as well as the fact that P. warreni is able to accumulate relatively high levels of nickel in various tissues, suggest that this freshwater crab is a potential indicator of nickel pollution in aquatic ecosystems. [ABSTRACT FROM AUTHOR]