Occurrence of Polychlorodibenzothiophenes in Nanjing Section of the Yangtze River, China

Sediment and water samples collected from 8 sites of the Yangtze River in Nanjing section were characterized with 31 congeners of polychlorodibenzothiophenes (PCDTs). Concentrations and percentage compositions of these PCDTs in water and sediments were analyzed by gas chromatography–mass spectrometry. Results showed that ∑PCDT concentrations in sediments were higher (0.86–1.75 μg/kg) than those in water (0.56–1.30 μg/L). A linear relationship existed between ∑PCDT concentrations and total organic carbon content in sediments, whereas there was a poor linearity between ∑PCDTs concentrations and dissolved organic carbon content in water phase. Moreover, percentage compositions showed that penta-chlorinated DTs were the predominant congeners both in sediments and water. Differences existed in the percentage compositions between water and sediments. Highly chlorinated DTs accounted for a larger proportion in sediments than those in water. In conclusion, the present study showed the prevalent contamination by PCDTs in sediments and water from the Nanjing section of the Yangtze River.