Human exposure to indoor organic contaminants, with emphasis on novel brominated flame retardants.

摘要

Oganohalogenated compounds (OHCs) cause considerable environmental pollution and health problems due to their persistence, bioaccumulation, and toxicity. Many OHCs, e.g. polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and organochlorinated pesticides (OCPs), are extensively studied in the literature. As a result, the Stockholm Convention on persistent organic pollutants puts regulations to eliminate/restrict their production and use. Restrictions on the use of PBDEs formulations in many countries have created a market for the use of novel brominated flame retardants (NBFRs) to meet flammability standards.;The main focus of this thesis study was to investigate the occurrence of NBFRs in our indoor environment and the estimated human exposure via indoor dust ingestion. Improved analytical methods, based on solid phase extraction and gas-chromatography coupled with mass spectrometry (GC-MS), for the monitoring of NBFRs along with other classes of OHCs in different environmental matrices were optimised and applied on samples from different countries.;NBFRs were detected in indoor dust of various countries (Belgium, Kuwait, New Zealand, Pakistan, Thailand, UK and Romania) at similar levels to the regulated PBDE suggesting their use a replacement in consumer products. The computed human exposure via indoor dust ingestion was considerably lower than reference dose values. Most OHCs, especially DDT and PBDEs were significantly higher in cats than in dogs. In human serum from Pakistan, levels of different OHCs were measured in mother-children pairs from the same rural/urban household. Levels of ΣDDTs were significantly higher in children from rural area compared to their urban counterparts. Levels of OHCs were higher in children compared to their mothers. OHCs were also investigated in matched samples of human serum and dust from different occupational settings of Pakistan. Flame retardants were the major contaminants in dust, while OCPs were higher in serum. Levels of Penta BDE congeners were positively correlated between serum and dust samples, indicating dust as an important exposure pathway. The current thesis shows increasing evidence of OHCs, especially NBFRs, in the indoor environment. Some NBFRs are fairly new to the consumer market and their use is expected to increase in future. Lastly, several research gaps were identified with proposed actions.