Genotoxicity and mutagenicity of electronic waste leachates using animal bioassays

Human exposure to electronic waste (e-waste) is increasing, especially in developing nations. This has potential short and chronic adverse health risks. Information is currently scarce on potential genotoxicity of e-waste leachate. In this study, the potential mutagenic and genotoxic effects of leachates from e-waste dumpsites at two electronic markets in Lagos, Nigeria, were investigated. The assays utilized were: bone marrow micronucleus (MN) and chromosome aberration (CA), spermatogonia CA, sperm morphology, and sperm count in mice. Experiments were carried out at concentrations of 1%, 5%, 10%, 25%, and 50% (v/v; leachate: distilled water) of leachate samples. MN analysis showed a concentration-dependent induction of micronucleated polychromatic erythrocytes (MNPCE) across the treatment groups. In the CA tests (bone marrow and spermatogonia), there was concentration-dependent significant reduction in mitotic index and induction of different types of CA. Assessment of sperm shape showed a significant increase in sperm abnormalities with significant decrease in mean sperm count in treated groups. Heavy metals analyzed in the tested samples are believed to contribute significantly to the observed genetic damage. This indicates that e-waste contains potential genotoxic agents; and constitutes a genetic risk in exposed human population.