RESIDUAL LEVELS OF HEXACHLOROCYCLOHEXANES (HCHs) AND DICHLORO-DIPHENYL-TRICHLOROETHANES (DDTs) IN MARINE ENVIRONMENT MEDIA OF MINJIANG ESTUARY, SOUTHEAST CHINA

摘要

Minjiang estuary is located on the Taiwan Channel which receives industrial and agricultural effluents. Samples including sediments (n=30), water (n= 10) and marine species (n=10) were collected from this bay. HCHs (hexachlorocyclohexanes) and DDTs (dichloro-diphenyl-trichloroethanes) were tested using GC-ECD. In sediments, the concentration of HCHs was 0.1-3.59ng/g and the concentration of DDTs was 1.56-81.68ng/g. The concentration ranges of HCHs and DDTs in sea water were 1.31-9.96ng/L and 0.78-6.51ng/L, respectively. And the concentration ranged of HCHs and DDTs in land surface water were 7.04-14.08ng/L and 3.82-9.66ng/L, respectively. The residual level of HCHs and DDTs in marine species samples ranged from 0.1 to 0.6ng/g and from 0.57 to 85.02ng/g, respectively. In this thesis, discussions of DDTs and HCHs in sediment, water and marine species samples were made. The following are the main results and conclusions: When compared with some remote sites, the concentration of HCHs and DDTs in Minjiang estuary is higher. While compared with other industry area, the residual level of them is lower. A general decreasing trend of HCHs and DDTs was found from the inner to outer sectors of the Bay for both sediment and water samples. The distribution of HCH and DDT depends greatly on the different properties pertaining to them. The topography, redox, hydrodynamic condition as well as other factors also play an important role in controlling the distribution and fate of HCHs and DDTs. Bioaccumulation factor of DDTs and HCHs was also calculated and human consumption of this seafood could be a risk because the bioaccumulation factor ranged from 0.50 to 267.6.