| This dissertation focused on the organic pesticides' environmental behavior and its effects in the estuarine agricultural watershed. We chose the Wuchuan watershed (WCW, one little branch of Jiulong River watershed, did sampling in July, Sep., Nov.,2000 and runoff sampling in Dec.,2000) and Jiulong River Estuary(JLRE, one cruise in Dec.,2000) as our study areas. And the organic pesticides focused on 18 Organic chlorine pesticides (Ocls) and 17 Organic phosphorus pesticides (OPPs). The results are,We established the analytical method of organic pesticides (OPPs and Ocls) in the multiphase matrices. The limit of determination( LOD) of our method on OPPs in water, soil(sediment) and plants is 0.07ng/L, 3.34pg/g, 0.03ng/g respectively. Accordingly, and the LOD of Ocls is 0.39pg/L, 0.03pg/g, 0.24pg/g.The recovery and relative standard deviation (RSD) meets the requirement of USEPA which recovery is 70-130%, and RSD is less than 30%. It is concluded that our method could be applied in the determination of organic pesticides at multiphase matrices widely.We did sampling and research on the environmental behavior of organic pesticides in Wuchuan Watershed in July, September, November and December , 2000. It was found that 3 -HCH,DDE occupied the most part of HCHs,DDTs respectively in the multiphase matrices, due to the more stable characteristics of 3 -HCH and DDT mainly degraded to more stable DDE. It implied that residues of HCHs and DDTs are mainly from the large usage in the history. The concentrations of endosulfans ( I + II) are more than that of Endosulfan sulfate in Wuchuan agricultural basin, implied that there are endosulfans input in the watershed. The ratio of a -HCH/ 6 -HCH equals to 0.28-7.31, it suggested that the HCH input are mixture of Lindane and industrial HCHs.MAP, Omethoate, DDVP, Malathion and Dimethoate occupied more fifty percent of the total 17 OPPs sum, especially the MAP, occupied about twenty percent. It is caused by the characteristics of pesticides usage at Wuchuan Watershed. Which is the same to the pesticides usage characteristics in our country. Except for endosulfans, the distribution characteristics of organic pesticides at water from Jiulong River Estuary are same to the Wuchuan watershed, which implied the similar source and the pesticides flux to the waterbody at JLRE from the basin where is in Jiulong River Watershed.The positive correlation between SPM and organic pesticides (Ops) in the surface runoff water, due to the leaching of SPM with Ops from soils in the runoff process, implied the surface runoff water is the carrier of Ops which entered into water body. The seasonal distribution characteristics of Ops indicated that Ocls concentrations in water changed positively with the temperature in some extent, but the OPPs contents not. It was because that the Ocls mainly came from the residue of historical using, with higher Kow and lower solubility relatively, so Ocls concentrations in water will be affected the air input, which may be greatly affected by the temperature. While the OPPs in water mainly came from the current agricultural usage, so the OPPs content in water mainly depended on current usage.Concentrated factors (CF) of Ops in plants, soils and sediments indicated that CF of plants was the highest, and CF of sediments was lowest relatively, due to the organic and lipids content difference among these matrices. CF of Ocls was higher than CF of OPPs in soils, while CF of Ocls was lower than that of OPPs in sediments. It maybe due to the KQW, solubility difference between Ocls and OPPs, added the water content of soils and sediments.The correlation among components of Ops indicated, in general, that of Ocls was more positive than that of OPPs in the components correlation at Wuchuan watershed and Jiulong River Estuary. It is implied again that the source of Ocls was much morestable ( mainly came from historical usage) than that of OPPs (mainly from current usage). The organic pesticide components did not have obvious correlation with the...
|
PDF Full Text Request