Contamination of the Potable Water Supply in the Lead-Zinc Mining Communities of Enyigba, Southeastern Nigeria

Lead, zinc, and associated minerals have been mined in the Enyigba, Nigeria area for over 92 years, leaving accumulated sulphide dumps and contaminated mine water. Stream sediment, mine tailings, mine water, stream water, and groundwater were sampled and analysed to determine the sources of potentially harmful elements in domestic water. The mine water contained mean concentrations of Cd, As, Co, Cr, Mn, Pb, and Ni that greatly exceeded those of the stream water, but samples from the streams and groundwater exceeded Nigerian drinking water and WHO thresholds for Al, Fe, and Pb, except for acceptable Pb concentrations in the borehole. Mn concentrations in one stream also exceeded Nigerian and WHO threshold for drinking water. In addition to the Pb-Zn mining, geological weathering also contributed to Pb, Al, Fe, and Mn contamination in the area.