Environmental Impact from Lead-Zinc Mining and Lead-Arsenic Toxicity Effects in Arufu Area, NE Nigeria.

Abstract

The six Upper Cretaceous lithogenic formations that formed the stratigraphic succession in the Arufu area are made up of Albian Arufu, Uomba and Gboko Formations i.e the Asu River Group. This is overlain by the Cenomanian –Turonian Keana and Awe Formations and the Cenomanain –Turonian Ezeaku Formation. The Ezeaku Formation is conterminous with the Konshisha River Group and the Wadata Limestone in the Makurdi area. The aim of this investigation is to reveal the impact of lead-zinc mining and highlight the effects of lead-arsenic to human health. Fifty soil and stream samples were analyzed using the Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES) technique. The values for the concentrations of the three elements ranges from; As (0 - 97.19ppm), Cd (0 - 4.653ppm), Pb (3.357 - 59660ppm). Multiple correlation and regression analysis of the geochemical data showed a relationship between Pb and As and significant regression of Pb on As and Cd. Results of the Index of geoaccumulation (Igeo), Contamination Factor (CF) and Degree of Contamination (Cdeg) indicate moderate to high Pb and As contamination. The values obtained indicates As, Pb and Cd have concentrations above maximum permitted levels of 0.01ppm, 0.01ppm and 0.003ppm respectively in water for human consumption, and above the threshold of contamination of 15ppm and 20ppm for As and Pb respectively. This suggests that more people will be at risk of pollutants as lead – zinc exploitation proceeds. Lead and arsenic values15ppm and 20ppm were found exceeded the threshold 0.01ppm, 0.01ppm and 0.003ppm set by Standard Organization of Nigeria which is potentially highly toxic to biological systems and in water for human consumption. Fresh and old mining sites across the area should be revisited with the aim of assessing the level of environmental risk they pose to the health of the people in those communities and putting up measures to contain it.