Seasonal variation in trace metal concentrations in water and sediment samples from selected mining ponds in Jos south and Barkin Ladi, LGA, Plateau state

Abstract

Trace metals contamination of surface water and sediments remain a global threat to biodiversity and humans. The study was carried out to assess the variation pattern in trace metals concentration in water and sediments samples from selected mining ponds in Jos South and Barkin Ladi for the period of February and March (Dry season) and July and August (Wet season), 2019. Metal concentrations were analysed using the PG-990 model atomic absorption spectrophotometer after HNO3-HCl digestion in the ratio of 1:3 (aqua rigia). Results of the analysis showed that higher metal concentrations of Pb (0.06 mg/kg), Cd (0.02 mg/kg), As (0.31 mg/kg) and Ni (0.19 mg/kg) were recorded in dry season than wet season for water samples. The concentration of toxic metals Pb, Cd, As and Ni were higher than the recommended values reported by WHO/USEPA (2000) for water samples. Mean relative abundance of trace metals in water occurred in the order Zn>Cu>As>Ni>Cu>Pb>Cd for dry season and Zn>Ni>As>Pb>Co>Cu>Cd for wet season. For sediments, the mean relative abundance of trace metals occurred in the range Zn>Ni>Cu>As>Ab>Co>Cd for dry season and Zn>Ni>Pb>As>Co>Cu>Cd for wet season. Generally, the concentrations of Pb (14.78 mg/kg), Cd (4.23 mg/kg), As (16.73 mg/kg) and Ni (26.48 mg/kg) in the sediments exceeded the International Sediment Quality Guidelines, ISQG (2000) and could have adverse effect on aquatic organisms.