Oxidative Stress and Antioxidant Status in Nigerian E-waste Workers: A Cancer Risk Predictive Study

Abstract

Introduction: In Africa, Nigeria has been reported as the largest destination for unregulated volume of electronic waste (e-waste). Currently, e-waste management practices in Nigeria remain completely primitive, taking place essentially in the informal sector. Recent report indicates that the majority (88.8%) of Nigerian e-waste workers have exposure burden of ≥6 hours per day; ≥6 days per week, and reportedly worked without personal protective devices. These crude management practices enhance the workers’ exposure to electronic waste borne toxic and carcinogenic metals and chemicals through almost all body cavities. Objective: Concisely, this study aimed at evaluating the status of enzymatic and non-enzymatic oxidative stress biomarkers as cancer risk indices in Nigerians occupationally exposed to e-waste. Methods: Serum levels of malondialdehyde (MDA), uric acid (UA), albumin (ALB), total bilirubin (TBil) and conjugated bilirubin (Cbil.)] and activities of enzymatic antioxidants [glutathione reductase (Gr), catalase (Cat), superoxide dismutase (SOD) and glutathione peroxidase (GPx)] were determined in Nigerian e-waste workers (n=63) and in age-matched unexposed participants (n=41), using standard colorimetric methods. Results: Significantly elevated lipid peroxidation and raised uric acid levels were indicated in e-waste workers. Further to this, CAT, SOD and GPx were significantly reduced in e-waste workers compared with the unexposed human population. Comparatively different observations were not registered in the activity of GR and levels of ALB, TBil. and CBil. between exposed and unexposed participants. Conclusion: This study provides evidence that the oxidative stress observed in the studied population could be associated with occupational exposure to e-waste chemicals and may be a predictive mechanism for chemical carcinogenesis in Nigerians involved in primitive e-waste management.