Determination of polybrominated ethers and their methoxylated and hydroxylated metabolites in human serum from electronic waste dismantling workers.

In suspected cases of thyroid toxicity and neurotoxicity in the human body, the determination of methoxylated and hydroxylated metabolites of PBDEs in human serum samples is very important for health risk assessment. In the present paper, a sensitive analytical method was developed for the extraction and cleanup of PBDEs/MeO-PBDEs and OH-PBDEs in human serum. An efficient denaturation and extraction step was described, and two methods for lipid removal were evaluated. Recoveries, based on gas chromatography coupled with mass spectrometry in the negative chemical ionization mode (GC-MS-ECNI), were between 79.5 and 87.1% for the studied MeO-PBDEs. Recoveries were between 63.4 and 75.6% for the studied OH-PBDEs, which were generally slightly lower than those of the neutral compounds but still suitable for the analysis of these compounds in human serum. The developed method was further validated in five human serum samples from electronic waste dismantling workers. The results indicated that no selected methoxylated brominated diphenyl ethers metabolites were identified, however, three hydroxylated higher brominated diphenyl ethers such as OH-octaBDEs and OH-nonaBDEs were identified in human serum. The dominant ΣPBDE and ΣOH-PBDE concentrations in workers' serum ranged from 5.58 to 228.52 ng g-1 lipid and from 44.66 to 896.13 ng g-1 lipid, respectively. The levels of hydroxylated metabolites of PBDEs found in the electronic waste dismantling workers were similar or even higher than their precursors.