Occupational and dietary exposure to organohalogen substances, with special emphasis on polybrominated diphenyl ethers

Abstract: This thesis is aimed at widening the current knowledge base about human exposure to brominated flame retardants (BFRs), particularly polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol A (TBBPA). Data on exposures to some of the traditional organohalogen substances (OHS) have been included for comparative reasons. BFRs are produced and applied in large quantities for fire prevention purposes in our society today. The ongoing production and use may lead to a dramatic pollution problem in the future unless they are used with care. Human exposure to BFRs must also be understood, assessed and measures based on the scientific knowledge should be taken when necessary.Ambient air measurements of BFRs at an electronics dismantling plant showed significantly higher levels of hexa- to decabrominated diphenyl ethers (hexaBDE-decaBDE), tetrabromobisphenol A (TBBPA) and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE) than in any other indoor facilities, including IT intensive work environments. Serum PBDE levels in workers at a dismantling plant were found to have significantly elevated concentrations of hepta- to decaBDEs, compared to a non-exposed group of women, comprised of cleaners. Results were obtained that unambiguously show that decaBDE is bioavailable, even though it has a molecular mass of 959 and previously was regarded as not being bioavailable. The decaBDE is present both in the workers and in persons from the control group. The decaBDE has however also been shown to be much less persistent than other PBDE congeners, with a half-life in humans of approximately 7 days, while a heptaBDE was shown to have a half-life of almost 3 months. TBBPA was also shown at low levels in human blood and to have a short half-life. Human exposure to OHS via intake of contaminated fish has been studied in a group of Latvian and Swedish men with highly interindividual consumption of fatty Baltic Sea fish. The OHS levels observed in serum were significantly related to both age and fish consumption for PCB and DDE but not for 2,2',4,4'-tetrabromodiphenyl ether, representing traditionally studied and newer OHS, respectively.Methods for reliable analysis of PBDEs, TBBPA and other BFRs have been developed. Improvements have been made in the clean-up procedure to minimize interferences, avoid adsorption to glass and to apply a highly specific identification mass spectrometric method. The instrumental analyses have been improved by making changes in sample application to the gas chromatographic system and choice of column for the separations. With these methods, it has also been possible to detect and quantify compounds with high molecular weights, e.g. decaBDE in both air and serum samples. A more relevant presentation of concentration data is suggested, based on molar mass instead of weight.