Evaluation of Polybrominated Diphenyl Ether Flame Retardants in Electronic Waste Recycling Environments in Lagos State, South West Nigeria

Informal electronic waste recycling, which involves open burning, acid stripping, and mechanical dismantling of printed circuit boards, releases polybrominated diphenyl ether flame retardants into the environment at concentrations that pose persistent bioaccumulative risks to workers, nearby residents, and receiving environmental compartments. This study evaluates the distribution of polybrominated diphenyl ether congeners in soil, house dust, and ambient air at two informal electronic waste recycling sites in Lagos State, South West Nigeria, and at a reference urban residential site. Polybrominated diphenyl ether extraction from solid matrices employs pressurised liquid extraction, while air samples are collected on polyurethane foam cartridges. Cleanup involves multilayer silica-alumina gel column chromatography, and analysis is performed by gas chromatography-high-resolution mass spectrometry for congener-specific quantification. A panel of sixteen polybrominated diphenyl ether congeners is targeted, prioritising those listed on the Stockholm Convention. Spatial distribution analysis examines contamination gradients as a function of distance from burning and dismantling activity zones. Occupational inhalation exposure estimates are calculated for adult male recyclers. Health risk assessment using United States Environmental Protection Agency chronic toxicological reference values characterises cancer and non-cancer risks. The study also examines polybrominated diphenyl ether profiles in wipe samples from workers' hands to estimate dermal exposure contributions. Findings provide the first systematic polybrominated diphenyl ether contamination assessment for Lagos electronic waste sites, informing national Stockholm Convention implementation obligations. Keywords: polybrominated diphenyl ethers, electronic waste, flame retardants, Lagos, exposure assessment