Comparative assessment of heavy metal contents in organs and flesh of marketed cane rat (Thryonomys swinderianus Temminck, 1827) along five highways in south-western Nigeria

Abstract

Comparative heavy metal pollution in organs and flesh of marketed cane rat along five highways in southwestern Nigeria was studied. Twenty-three wildlife markets were visited and there, samples were taken randomly on quarterly basis. Visceral organs of raw kidney, liver, lung, flesh and roasted flesh of Thryonomys swinderianus (cane rat) as the most sourced wild animal were taken and screened using Wet Digestion Method for heavy metals including lead, cadmium, chromium, astatine, copper, manganese and cobalt. Results showed that lung had the least contamination, followed by kidney, then liver; raw flesh and lastly roasted meat as the highest. Chromium and Astatine were significantly different in distribution (0.017 and 0.049 respectively) at P˃ 0.05.Follow-up procedures showed that at P˃0.05, for Astatine, the descending order was concentration was Roads,5 4, 2, 3 and1 . For chromium the distribution order was Roads 5, 4, 3, 2 and 1 also in descending order. Average values in all the samples pooled together showed lead falling within the permissible range of 0.5mg/kg for offals and 0.1 mg/kg for meat, Copper exceeded the values of 0.01 mg/kg flat along all market Roads for both categories, chromium was within the safe limit of 1.00mg/kg for both meat and offals; cadmium was within the safe range of 0.5 mg/kg for both offals and meat throughout the study areas. Cobalt exceeded the value of 0.08mg/kg for offals and 0.03 mg/kg for meat along Road 3 only. Manganese and astatine fell within safe range of 0.5 mg/kg for both samples classes limit. Expansion of environmental conservation strategies was recommended. It was concluded that the marketed wildlife in the study area are partially safe for consumption.

Keywords: analysis, contamination, Heavy Metal, highways, markets, Wildlife