Occurrence, sources, and human health risk assessment of polybrominated diphenyl ethers in herbal medicinal preparations in Nigeria.

In this study, the concentrations of thirty-nine (39) polybrominated diphenyl ether (PBDE) congeners were evaluated in orally applied herbal medicinal preparations (HMPs) in Nigeria. The PBDEs were quantified by gas chromatography-mass spectrometry. The Σ39 PBDE concentrations in the HMPs varied from 2.00 to 313 ng g-1 with a mean concentration of 55.6 ng g-1. The homologue distribution patterns in the HMPs indicated dominance of low brominated PBDEs such as mono-, di-, and tri-PBDEs, which reflected the prevalence of plant-metabolized and processing method-mediated debromination products of PBDEs. The results for the risk assessment indicated that the use of the HMPs for treating medical conditions does not pose any lifetime carcinogenic or non-carcinogenic risks.