Polycyclic aromatic hydrocarbons in the sediments of the South China Sea

Sixteen sediment samples, collected from the South China Sea, were analyzed for II parent polycyclic aromatic hydrocarbons (PAHs) using gas chromatogr aphy and gas chromatography-mass spectrometry. Total concentrations of the 11 PAHs studied in the sediments ranged from 24.7 to 275.4 ng/g with a mean of 145.9 ng/g dry sediment. PAH concentrations displayed a consistent dist ribution trend with the sediment organic carbon content. The linear regress ion analysis showed that the total concentration of PAHs in the sediment wa s significantly correlated to the sediment organic carbon content with a co rrelation coefficient of 0.735 (n = 16). Special PAH compound ratios, such as phenanthrene/anthracene and fluoranthene/pyrene, were calculated to eval uate the relative importance of different origins. The collected data showe d that pyrolytic input from anthropogenic combustion processes was predomin ant at almost all the stations investigated. Only one station, located in t he proximity of oil wells, appeared to be contaminated predominantly by pet rogenic input. Three anthropogenic PAHs, i.e. pyrene, benzo[a]pyrene and be nzo[e]pyrene, exhibited similar distribution patterns in the studied area, implying that these compounds possess identical sources. However, perylene did not entirely follow the distribution trend of the three PAHs, suggestin g that the sediment perylene probably derived from other sources such as in situ biogenic origins. Dibenzothiophene, a sulfur heterocyclic aromatic co mpound, was also measured in this study. (C) 2000 Elsevier Science Ltd. All rights reserved.