Abstract

The study was conducted to assess the extent of heavy metal contamination from mining and irrigated lands in selected districts of the Upper East Region, Ghana. Heavy metals such as Cu, Pb, Cd, Cr, Co, and Hg were determined by atomic absorption spectroscopy. Ecological risk assessment used included the contamination factor, geoaccumulation index, pollution load index (PLI), and enrichment factor in soils and plant leaves. The mean concentrations ranged from 0.04±0.01 mg/kg in Tono to 0.10±0.02 mg/kg in Nyamerega for copper, 0.02±0.01 mg/kg in Sumbrungu to 0.05±0.01 mg/kg in Nyamerega for Pb. 0.13±0.01 mg/kg in both Vea and Sumbrungu to 0.15±0.01 mg/kg in Nyamerega for cobalt, 0.05±0.01 mg/kg in Nyamerega to 0.20±0.01 mg/kg in Sumbrungu for chromium, 0.04±0.01 mg/kg in Tono to 0.11±0.01 mg/kg in Sumbrungu for Hg, For Cd, 0.03±0.01 mg/kg in Vea to a high of 0.10 mg/kg in Tono. The correlation among heavy metals was significant at both 1 and 5% levels. Cu, Pb. Cd contributed a total of above 84%. Cr, Co, and Hg contributed 10.8, 3.5, and 1.3%, respectively. Ecological risk assessment reveals low contamination levels of Cu, Pb, Cr, and Hg. However, Cd and Co were low to moderately high in polluted soils. Mining activities were safe in these areas since the harmful chemicals used were low. Farmers must adopt an environmentally friendly approach to remove heavy metals and protect their lands for agricultural purposes.

Key words: Heavy metals, irrigable lands, contamination factor, enrichment factor, geoaccumulation index, pollution index, ecological risk.