a b s t r a c tThe present study investigated the source characterization of the polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) into sediments of Aqaba Coastal City. Air samples from four location sites and sediment samples from five stations on the Jordanian coast of the Gulf of Aqaba, including 25 individual sediment samples merged by station to form five composite samples, were collected and analyzed for PCDD/Fs. Congener patterns of all air samples were characterized by high octa-chlorinated dibenzo-p-dioxin (OCDD) (78% of the ΣPCDDs), followed by octa-chlorinated dibenzofurans (OCDF) (38.5% of ΣPCDFs) and 1,2,3,4,6,7,8-HeptaCDD/Fs. The highest atmospheric concentration values of the total PCDD/Fs were measured at the middle of industrial complex. The results of sediment samples show that among the PCDD/Fs congeners, the OCDD, 1,2,3,4,6,7,8-HeptaCDF, 1,2,3,4,7,8,9-HeptaCDF and OCDF were the prevailing congeners (approximately 77.5%-90%), indicating air and sediment sharing the same main source of pollution. The most toxic congener of the dioxin group 2,3,7,8-TCDD was a very minor component with a contribution of less than 0.54% to the total PCDD/Fs. The toxic equivalents (TEQ) values ranged between 0.011 and 1.08 pg TEQ/g dry matter for all sediments. Concentrations in all sediment samples analyzed significantly below the safe limits. The substantial fraction PCDD/Fs emissions enter air and then carried into the waterway via urban storm water runoff could be the main source of the low concentrations recorded.
