T5 PM Emerging Pollutants
Tuesday, 15 November 2005: 1:50 PM - 5:30 PM in 321-323
(BEG-1118-211734) Polybrominated Diphenyls in the Kuwaiti Environment.
Gevao, B.1, Beg, M.1, Helaleh, M.1, Zafar, J.1, 1 Environmental Sciences Department, Kuwait Institute for Scientific Research, P.O. Box 24885, Safat-13109, Kuwait
ABSTRACT- Polybrominated diphenyl ether (PBDE) concentrations were measured in surficial sediments from coastal sediments receiving industrial and municipal effluents in Kuwait. The 
PBDE concentrations varied by two orders of magnitude ranging from 80 to 3800 pg g-1 dw. The congener distribution was dominated by BDE-183, with minor contributions from BDE-154, and BDE-153. This contrasted sharply with the congener distribution in ambient air in Kuwait, with congeners 47, 99, 100, 153, and 154 being the congeners routinely detected (in order of decreasing concentrations). The profile in air was remarkably similar to that in Bromkal 50-7DE, the technical penta mixture whereas the sediment profile is indicative of the octa technical mixture. The absence of BDEs 47, 99, and 100, in sediments, which together constitute ca 90% of the PBDE concentration in ambient air in Kuwait, suggests either a selective deposition/retention of the high molecular weight, more hydropbhobic congeners, or direct inputs of a different technical mixture possibly via wastewater discharges to the sea. A combination of low annual precipitation rates and high annual ambient temperatures supports the first scenario, because these factors will favour the selective deposition of high molecular weight congeners (e.g. BDE-153, -154, -183) which will predominantly be associated with aerosol as opposed to the more volatile congeners (e.g. BDE-47, -99, -100) that will predominantly be in the gas phase. However, the observed gradient in concentration distribution, with high PBDE concentrations near the shore and an exponential decrease seaward, indicates that the second scenario is more likely and suggests that atmospheric deposition may not an important delivery mechanism of these contaminants to the sediment.
Key words: polybrominated diphenyl ether, sediment, ambient air, Kuwait