Soil elemental concentrations, geoaccumulation index, non-carcinogenic and carcinogenic risks in functional areas of an informal e-waste recycling area in Accra, Ghana.

Abstract

This study assesses the distribution, contamination and human health risks of major, minor and trace elements in the topsoil and subsoil of two informal e-waste recycling sites in Accra, Ghana. Metal concentrations in Agbogbloshie exceeded the Dutch Soil intervention values with exceedances of 72%, 57%, 57%, 38%, 16%, 2% for Cu, Zn, Pb, Ba, Cd and As respectively. Metal concentrations in Ashaiman exceeded the Dutch Soil intervention values with exceedances of 62%, 57% and 46% for Cu, Zn and Pb respectively. Geoaccumulation indices indicated that the topsoils of the burn area and dismantling areas of Agbogbloshie e-waste recycling site were strongly contaminated by Pb and uncontaminated by Cr, Fe, As and Ba. Lead (Pb) contributed greatly to non-carcinogenic ingestion hazard quotient for residents living near Agbogbloshie and Ashaiman e-waste recycling sites while arsenic (As) presented carcinogenic risks to children from the dismantling area topsoils. Non-carcinogenic risks from ingestion were significant with children being more susceptible to non-carcinogenic ingestion risks than adults. Non-carcinogenic risks from dermal exposure were negligible. Hazard quotients of Pb for children in burn area topsoils and dismantling area topsoils were 7.4-7.6-fold greater than that for adults. The mean geoaccumulation indices values of Pb and Cu indicated extreme contamination of topsoils with these elements. A novel environmental assessment tool based on the Agency for Toxic Substances and Disease Registry (ASTDR) total impact points confirmed Pb and Cu as the most toxic elements.