Potential Toxic Element (PTE) Soil Concentrations at an Urban Unregulated Ghanaian E-waste Recycling Centre: Environmental Contamination, Human Exposure and Policy Implications

Electronic (E)-waste recycling is of ever-increasing concern as disused electronic items in developed countries are routinely shipped to developing countries for recycling. This recycling is often unregulated and rudimentary, and takes place in urban settings where it can cause direct exposure of the surrounding human populace. E-waste is often burnt at low temperatures, resulting in both organic and inorganic contamination. This study set out to investigate the extent of contamination at two locations within an urban Ghanaian e-waste recycling centre by assessing the residual impact of activities in soils. Comparison of e-waste soil potential toxic element (PTE) concentrations to those in Ghanaian baseline and mine spoil soils showed considerably greater contamination from e-waste. Generally, PTE concentrations increased in the order: baseline soils < mine spoil soils < e-waste soils, except in the case of lead (Pb) where baseline and mine spoil soils switched positions. At median concentrations, cobalt enrichment was 2- to 4-fold higher in the e-waste soils than in mine spoil soils, while arsenic was 3- to 5-fold higher. With reference to the baseline soils, manganese, nickel and bismuth concentrations were, respectively, up to 4-, 11- and 53-fold higher in the e-waste soils. Median cadmium, zinc, copper and Pb concentrations were, respectively, up to 170-, 213-, 231- and 263-fold higher in the e-waste soils compared to the mine spoil soils. The human exposure implications of e-waste burning are discussed along with policy recommendations aimed at ensuring the social and environmental sustainability of e-waste recycling.