Heavy metals and metalloid accumulation in livers and kidneys of wild rats around gold-mining communities in Tarkwa, Ghana

Previous studies revealed high levels of metals in soils, drinking water, foodstuffs and food animals in several communities in Tarkwa, Ghana. Therefore wild rats were trapped from 16 communities in Tarkwa to estimate the environmental pollution state of metals; determine differences in sex in metal accumulation; and assess the potential risks involved. Concentrations of arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) were measured in the livers and kidneys of wild rats; and livers accumulated higher levels of As than kidneys but the reverse was for Cd and Pb. In both organs, As, Cd and Zn levels were higher in female than the male rats. There was a strong positive correlation between body weight and Cd concentrations in livers and kidneys of wild rats which reflects a mechanism of protection against the development of osteopenia, although a biological effect remains a concern. Pb levels in the kidneys could cause intra nuclear inclusion bodies and karyocytomegaly in the proximal tubular cells in 29% of wild rats in Tarkwa and structural and functional kidney damage in 6%. Concentrations of As in kidneys of these wild rats could cause glomerular swelling in 9% of rats. Principal component analysis of the results showed that wild rats in Tarkwa were exposed to heavy metals and a metalloid through borehole drinking water and soils. Key words: Wild rats, heavy metal, metalloid, liver, kidney, Ghana.