ZHU Xiao-hua1, PAN Jing1, LU Guo-hui1, CHEN Da-zhou2, TANG Hua2, WANG Zhuo1，LIU Xiao-duan1, YANG Yong-liang 1,*
(1. The Key Laboratory of Eco-geochemistry, Ministry of Land and Resources of China, National Research Center of Geoanalysis, Beijing 100037, China;
2. Division of Metrology in Chemistry, National Institute of Metrology, Beijing 100013, China)
Abstract: The concentrations of hexachlorocyclohexanes (HCHs) in the sediment cores taken from the Dongtan Wetland at the Yangtze River Estuary of the East China Sea were measured by isotope dilution mass spectrometry (IDMS) with HRGC-HRMS. The vertical distribution characteristics of HCHs concentrations with depth and possible influence by climate changes were preliminarily discussed. HCHs were found in all sediment layers. The total HCHs concentrations range from 0.35 to 0.98 ng﹒g-1 dw with the average of 0.64 ng﹒g-1 dw for the Dongtan Wetland, showing a low pollution level. The vertical distributions of HCHs isomers in the cores showed significant periodic variations. By time-series analysis, the long-term variation trends and frequency spectra of HCHs in the sediment cores of the Dongtan Wetland during the last 60 years were discussed. The long-term variation trends of HCHs in the wetland showed that these chemicals began to rise in the early 1950s with the maxima during the 1960s~1970s. Some isomers did not show significant declining trends after their productions were banned. The time-series generally show an 8-year periodicity, suggesting an influence of ENSO.
Key words: organochlorine pesticide; IDMS; sediment core; Dongtan Wetland
EARTH AND ENVIRONMENT Vol. 42, No.4, Tot No.300, 2014, Page 496-501
