Evaluation of metal contaminants of surface water sources in an active Pb-Zn mine pit and a nearby pond: comparison of levels of contamination

Abstract

This study evaluated the potential health risks associated with domestic use of surface water from an active Pb-Zn mine pit, compared to a nearby pond. The concentrations of Pb, Zn, Mn, Co, Cu, Ni and Cr were quantitatively determined in water samples collected from Enyigba Pb-Zn mine and a nearby Uruva pond using atomic absorption spectrophotometer. The results showed varying concentrations of these metals in the samples. The mean values of the metals (mg/L) in the samples from the pit mine (in bracket from Uruva pond) are Pb – 0.80 (0.50), Zn – 0.14 (0.08) , Mn – 0.20 (0.16), Co – 0.07 (0.07), Cu – 0.30 (0.12), Ni – 0.31 (0.80) and Cr – 0.19 (0.23). When compared with World Health Organisation (WHO) recommended limits for metals in drinking water, the values of Pb, Mn, Ni and Cr exceeded the limits in both samples while the values of Zn, Cu and Co were below the limits. The levels of significant differences in the sources of concentrations of the metals in both samples were tested at 95% confidence level (α = 0.05) using F- and student’s t-tests. It showed no evidence of differences (t_exps < t_crits), suggesting that the metal contamination of the water samples originated from common sources, such as the soil geochemistry of the area

KEYWORDS: metal contamination, Pb-Zn mining, surface water, Enyigba mine pit, Uruva pond