| Methods for determination of organochlorine pesticides and polychlorinated biphenyls in marine environment are studied.Eight organochlorine pesticides are determined by GC/MS, with SIM scanning mode. Twenty-four organochlorine pesticides and polychlorinated biphenyls are determined by GC/ECD. The recoveries for 8 organochlorine pesticides using liquid-liquid extraction and GC/MS-SIM for determination range from 62.2% to 101.1%, and RSD from 8. 1% to 19. 1%.The optimized conditions of SPE extraction are as follows, solid phase:florisil, enriching velocity of aqueous samples:5mL/min, eluting velocity for target compounds:3mL/min, volume of reagent for elution:10mL hexane and 5mL dichloromethane. Using this method, the recoveries for thirteen of the total target compounds, including six organochlorine pesticides and seven polychlorinated biphenyls in seawater range from 33. 2%~133. 4% and 21. 6%~102. 3% respectively.The factors that affect the separation of 24 organochlorine pesticides and polychlorinated biphenyls are discussed. It is considered that the activity of the absorbent is an important factor. The optimized weight of the absorben is lOg florisil,which has been deactivated by adding 10-15% water.The recoveries of separation range from 60.0%— 117. 0%(except β-666).Twenty-four organochlorine pesticides and polychlorinated biphenyls from seawater and sediment in Laizhou Bay have been qualitatively and quantitatively analysed, using the methods which are tested and optimized in the paper. Among all the aqueous samples, six organochlorine pesticides are detected in the surface and bottom water, including β - HCH, γ- HCH,δ—HCH. p, p' -DDD, o, p' -DDT and p, p' -DDT. The total concentration of organochlorine pesticides ranges from nd~ 32. 9ng/L, and the average concentration is 4. 2ng/L. organochiorine pesticides are detected in all water samples except bottom water samples of site 2#, 4# and 6#. As to polychlorinated biphenyls, only two of them are detected in aqueous samples, which are 2,2' ,4,4' -tetraPCB and 2,2' ,4,4' ,5,5' -hexa PCB, with total concentration of 0.7ng/L — 27.7ng/L and average value 5. 3ng/L. 2,2' ,4,4' -tetraPCB is detected in all bottom water samples. Five of 24 target compounds are detected in the sediment samples of Laizhou Bay, which are p, p' -DDT, endrin, dieldrin, alpha-666 and 2,2' ,5,5' -tetraPCB. The concentration of them is as follows, p,p' -DDT(18.2pg/g dw)> endrin(5.1pg/g dw)> 2,2' ,5,5' -tetraPCB > (1. 5pg/g dw)> dieldrin (0. 6pg/g dw) > alpha-666(0. 5pg/g dw). The five detected compounds are only found in samples of site 1#, 2#, 6# and 12#. The paper studies the distribution characteristics of 24 organochlorine pesticides and polychlorinated biphenyls in Laizhou Bay, and the possible source of 24 organochlorine pesticides and polychlorinated biphenyls is also discussed. From the concentration contour of total organochlorine pesticides in surface water, it can be observed that the concentration varies considerably between sites. The concentration of sample 1# is very high due to the effect of input of rivers. There are several rivers around Laizhou Bay, most of which are more or less polluted by coastal industrial and agricultural production. Among the rivers,Xiaoqing River is considerd to be the most polluted, therefore, concentration of total organochlorine pesticides in sample 1# is the highest of all sites.The 24 target compounds are transitted and diluted by seawater movement after they enter Laizhou Bay. So the concentration is high where the sampling site locates near the entrance of the rivers.The relationship between total organochlorine pesticides and the general parameters, such as salinity, chlorosity, pH and dissolved oxygen, is studied. The results demonstrate that there is some correlation between total organochlorine pesticides and salinity,with coefficient value(R) 0.59. The relationship between total organochlorine pesticides and chlorosity is consistent well with that of total organochlorine pesticides and salinity. The results also show that pH and concentration of dissolved oxygen has little effect on the concentration and distribution of total organochlorine pesticides.
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