Polybrominated diphenyl ethers and polychlorinated biphenyls in indoor dust from electronic repair workshops in southern Nigeria: Implications for onsite human exposure

Abstract

The concentrations of 9 polybrominated diphenyl ethers (PBDEs) and 28 polychlorinated biphenyls (PCBs), including the 7 indicator PCBs and 12 dioxin-like PCBs, were determined in indoor dusts from electronic repair workshops in southern Nigeria. The study was aimed at providing information on the distribution and compositional patterns of PBDEs and PCBs in electronic repair workshop dusts as well as evaluating the human exposure risk to these compounds via non dietary ingestion, inhalation and dermal contact pathways. The PBDEs and PCBs in the electronic repair workshop dusts were extracted with a mixture of hexane/acetone by ultrasonication, and the extracts were purified with a multilayer silica gel/alumina column. The PBDEs and PCBs in the purified extracts were determined by means of gas chromatography-mass spectrometry. The concentrations of the PBDEs ranged from 14 to 2578 ng g−1 with a prevalence of 85 to 95% for BDE-28, BDE-47, BDE-99 and BDE-100. The hazard indices for PBDEs were >1 for exposure to dust from television/radio/stereo repair workshops whereas the total cancer risk values were within the acceptable range of 10−6 to 10−4. The Σ28 PCB concentrations ranged from 96.6 to 3949 ng g−1. The PCB compositional patterns indicate that hexa-PCBs are the most prevalent PCB homologues in the electronic repair workshop dusts. The TEQ for the dl-PCBs in the electronic repair workshop dusts ranged from 2.40 to 4.31 g−1. The estimated hazard indices and cancer risk values suggest that there is a substantial risk (carcinogenic and non-carcinogenic) associated with human exposure to PCBs in dusts from these electronic repair workshops. The principal component analysis results indicate that the PCBs in the electronic repair workshop dusts arise from inputs from the technical mixtures of Aroclor 1252, Aroclor 1254 and Aroclor 1260.