Mercuric pollution of surface water, superficial sediments, Nile tilapia (Oreochromis nilotica Linnaeus 1758 [Cichlidae]) and yams (Dioscorea alata) in auriferous areas of Namukombe stream, Syanyonja, Busia, Uganda

Abstract

The mercury content and the contamination characteristics of water, sediments, edible muscles of a non-piscivorous fish (Oreochromis nilotica Linnaeus 1758 [Cichlidae]) and yams (Dioscorea alata) from Namukombe stream in Busia gold district of Uganda were evaluated. Human health risk assessment from consumption of contaminated fish and yams as well as contact with contaminated sediments from the stream were performed. Forty-eight (48) samples of water (nD12), sediments (nD12), fish (nD12) and yams (nD12) were taken at intervals of 10mfrom three gold recovery sites located at up, middle and down sluices of the stream and analyzed for total mercury (THg) using US EPA method 1631. Results (presented as means ± standard deviations) showed that water in the stream is polluted with mercury in the range of < detection limit to 0.14 ± 0.040 ugg-1. Mean THg content of the edible muscles of O. nilotica ranged from < detection limit to 0.11 ± 0.014 ugg-1 while D. alata contained from