Richards Bay Harbour: Metal exposure monitoring over the last 34Â years

► We compared metal concentrations analysedin Perna perna between five sampling events from 1974 and 2009. ► Differences in metal concentration and activities taking place during different sampling events were investigated. ► Data were analysed using DFA and PCA. ► Results indicated that dredging and run off were the main causes of increased metal loads in 2005 and 2008. ► The data indicated that day to day running and harbour enlargement have not had a major effect on the environment.