Assessment of heavy metal pollution resulting from informal E-wastes recycling in the Greater Accra Region of Ghana

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Abstract This study investigated the levels and spatial distributions of four selected heavy metals in the soil and drainage components emanating from informal E-waste recycling activities at Ashaiman scrapyard, in the Greater Accra Region, Ghana. The metals are Cadmium (Cd), Chromium (Cr), Copper (Cu) and Lead (Pb). Five sampling sites were randomly selected, with top and sub-soil sampled from the two open burning areas (hereafter H and F). Three sites in the drainage that runs through the scrapyard were similarly selected for sample collection; a control upstream (soil-sediment-water; WSC) and two experimental units downstream (soil-sediment-water; WS1 and surface water only; WS2). Four control topsoil samples were taken at distances of 25, 50, 75 and 100 m away from the scrapyard. Composite sample of three sampling units per site, including pH analysis, with two replications per treatment, were investigated using standards methods. Spatial distribution of the metals in the scrapyard were analyzed using Inverse Distance Weighted (IDW) interpolation method. Coefficient of variation (CV) was used to investigate the source of pollution. The pollution levels were investigated using three criteria, namely Geoaccumulation Index (Igeo), Contamination Factor (CF) and Pollution Load Index (PLI). Correlation analysis was used evaluate the relationships between the metals. Mean CV of 88.5% suggests that the scrapyard pollution is anthropogenically-driven. Igeo of soil samples from the scrapyard revealed the following: (i) Cd and Pb (unpolluted to strongly polluted), (ii) Cu (unpolluted to moderately polluted), and (iii) Cr (unpolluted). CF revealed the following: (i) Cd (moderate to strong pollution), (ii) Cu (moderate pollution), (iii) Cr (low pollution), and (iv) Pb (high pollution), but the metals exhibited moderate PLIs. Spatial distribution maps revealed heavy metal pollution decline with distance away from the scrapyard, which was inversely related to pH levels. WSC showed lower heavy metal concentrations than WS 1, while the lowest levels were detected in WS 2. Generally, moderate to very strong correlations existed among the metals in the scrapyard. In conclusion, the scrapyard was the epicenter of E-waste pollution primarily driven by human activities.

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