Accumulation and health implications of arsenic, mercury, and selenium in selected freshwater fish species in the uMgeni River, South Africa

Metal pollution threatens freshwater ecosystems and consequently the well-being of human communities consuming fish. The study evaluated the concentration of arsenic (As), mercury (Hg) and selenium (Se) in six fish species in the uMgeni River, and the edibility thereof. Water, sediment and fish were sampled during low and high flow seasons in the Inanda and Nagle dams. Metals were below detection level in the water column whereas notable concentrations were observed in sediment. Arsenic and Se concentrations were within the guidelines for all species, whereas Hg exhibited concentrations exceeding the guidelines except for Clarias gariepinus, Micropterus salmoides, and Cyprinus carpio. For non-carcinogenic risks, the THQs > 1 was observed for As and Hg for all species except C. carpio whereas Se showed THQs < 1 for all species. These findings suggest that consuming fish from the uMgeni River could result in As and Hg related non-carcinogenic health hazards.