Distribution of dibenzothiophene in the sediments of the South China Sea

Sediment samples from 22 different sampling sites in the South China Sea were analyzed for dibenzothiophene using capillary gas chromatography with sulfur special flame photometric detector. Dibenzothiophene was found in all of the sediments investigated. Its concentrations ranged from 11 to 66 ng/g dry sediment. Dibenzothiophene content was higher nearshore relative offshore sediments, which was consistent with the distribution trend of the sediment organic carbon observed in the area. Linear regression analyses showed the concentration of dibenzothiophene were markedly correlated to the organic carbon and clay contents of the sediments, suggesting that the clay and organic carbon contents are two prime factors controlling the sediment dibenzothiophene levels. Probable source pathways of dibenzothiophene in this sea sediments, including terrestrial runoff, prude oil pollution and the input of airborne particulates formed from combustion processes, are also briefly discussed.