Pilot study on the internal exposure to heavy metals of informal-level electronic waste workers in Agbogbloshie, Accra, Ghana

Informal-level electronic waste (e-waste)-processing activities are performed at hotspots in developing countries such as India, China, and Ghana. These activities increase the ambient burden of heavy metals and contribute to the toxic exposure of the general population. However, few data exist on the internal exposure of populations involved in these informal activities and in close contact with fumes from the direct combustion of electronic waste products in these countries. Therefore, in a cross-sectional study design, we analyzed blood, urine, and hair samples from 75 e-waste workers residing in and/or working on a large e-waste recycling site in Agbogbloshie, Accra, Ghana, and compared the results against those of 40 individuals living in a suburb of Accra without direct exposure to e-waste recycling activities. A comparative analysis using the Mann-Whitney U test showed significantly higher median concentrations of blood lead (88.5 vs. 41.0 μg/l, p < 0.001), cadmium (0.12 vs. 0.10 μg/gcᵣₑₐ, p = 0.023), chromium (0.34 vs. 0.23 μg/gcᵣₑₐ, p < 0.001), and nickel (3.18 vs. 2.03 μg/gcᵣₑₐ, p < 0.001) in the urine of e-waste workers than those of controls. There was no difference in blood cadmium concentrations between the groups (0.51 vs. 0.57 μg/l, p = 0.215) or in urine mercury levels (0.18 vs. 0.18 μg/gcᵣₑₐ, p = 0.820). Hair mercury levels were higher in the controls than in the e-waste workers (0.43 vs. 0.72, p < 0.001). We compared our data with those from European populations, specifically using the German reference values, and found that the internal concentrations of the participants exceeded the German reference values in 59.3 vs. 3.1% (e-waste workers vs. controls) for blood lead, 56.9 vs. 52.5% for urine nickel, 22.2 vs. 20.0% for urine chromium, and 17.8 vs. 62.2% for hair mercury. In particular, the high blood lead levels of up to several hundred micrograms per liter are a cause for concern because many of the workers in Agbogbloshie are children or adolescents who are in developmental stages and are at a particular risk for negative health effects. We conclude that exposure to some of the heavy metals tended to be a citywide phenomenon, but populations directly exposed to e-waste recycling are experiencing higher exposure levels and have concentration levels much higher than those of the general population and much higher than those found in European populations. To achieve environmental sustainability and to minimize the impact of e-waste-processing activities in developing countries, national authorities must formalize the rapidly growing informal-level e-waste management sector in these countries by deploying cleaner and easy-to-operate e-waste processing technologies.