Zn and Cd accumulation in Potamonautes warreni from sites in the North–West Province of South Africa

Abstract

The freshwater crab, Potamonautes warreni, is endemic to rivers of the North–West Province, South Africa. Parts of this province are heavily mined for gold, diamonds and platinum. The rivers inhabited by P. warreni are therefore vulnerable to metal pollution from industry, as well as from other anthropogenic activities. Measurements of Zn and Cd in crab tissues (gill, midgut gland, muscle and carapace), sediments and water from sites on three tributaries of the Limpopo River near the town of Rustenburg were made. Ambient and accumulated Zn and Cd concentrations and water Na and Ca concentrations were used to investigate factors affecting metal accumulation. Zn and Cd concentrations in P. warreni varied between sites and tissues and a negative relationship was found at some sites between water Na and Ca concentrations and metal burdens of crabs. Sediment and water metal concentrations were not representative of metal accumulation in the crab tissues, indicating the importance of including biota in monitoring programs.