Heavy Metals in Soil and Vegetables Irrigated with Ex- Tin Mining Ponds Water in Barkin – Ladi Local Government Area Plateau State, Nigeria

Abstract

Tin mining pond water irrigated fields can cause potential contamination with heavy metals to soil and vegetables, thus pose a threat to human beings. The current study was designed to investigate the contamination of the soil with toxic heavy metals and their accumulation in edible vegetable crops. The heavy metals Pb, Cu, Cd, Zn, Cr, Fe, Mn and As were analyzed for their bioaccumulation factors to provide baseline data regarding environmental safety and the suitability of tin mining pond water for irrigation in the future. The contamination factor (CF) of these metals in the soil were calculated and indicated levels of metal contamination in the order of Cd > Zn > Pb > Cr > Cu > As ˃ Fe ˃ Mn. The concentrations of Pb, Cd, Cr, As, and Mn in the edible vegetables were above the safe limit prescribe by FAO/WHO, 2007 and EU, 2002 in all studied vegetables. The results indicated a potential pathway of human exposure to slow poisoning by heavy metals due to the utilization of vegetables grown on heavy metal contaminated soil that was irrigated with tin mining pond water sources. Amongst the studied vegetables, cabbage was safe from other metal except for As and Cr that were observed to exceeds tolerable limit. The irrigation source was identified as the source of the soil pollution in this study. Thus, the consumption of these vegetables might poses substantial health risk to consumers for this reason we therefore, emphasizes the need for proper remediation of the wastewater to reduce the health risk and the extent of heavy metals contamination.