INFLUENCE OF HEAVY METAL AROUND GOLD MINING CITES ON WATER, FISH AND SEDIMENT.

Abstract

The concentrations of heavy metals in water, sediment and fish (TillapiaMonsambicus) in the
three major dams in Zamfara State along gold mining vicinities were determined using
standard methods for two years (four seasons). The concentration of heavy metals determined
in water, sediment, and fish were generally high during the dry season with exception of Hg
which recorded its highest concentration across the seasons. Zn and Cr levels in the water,
sediment, and fish were within international safe limits while Cd (0.1022 mg/l), Pb (0.2104
mg/l) and Hg (1.8818 mg/l) levels were far above (0.01, 0.01 and 0.001mg/l) USEPA safe limits
respectively for drinking water. Two major pollution indices such as contamination factor (CF)
and pollution load index (PLI) were used for determining the contamination level of water,
sediment, and fish samples. The result showed a high contamination factor for Cd, Pb and Hg
in all the six locations accessed and a general overall pollution load across all the locations.
Generally, the concentration of the analyzed heavy metals in mg/l for water and sediments were
in the order of Hg>Pb>Cd > Cr > Zn. Correlation analysis revealed a significant and positive
relationship for Cd and Zn and Hg and Cr during the wet season and a significant positive
relationship at the (p>0.05) for Cr and Zn in the dry season. The pollution index value of the
water samples across all the three dams indicated that there is need for immediate intervention
to ameliorate pollution particularly in the dry season.