| As a typical new POPs material, endosulfan has drawn widely attention of researchers in recent years. The historical production site of endosulfan not only contains high endosulfan residue level but also the potential secondary pollution source released to environment and is the high risk region for endosulfan pollution. The study on the levels, occurrence characteristics and the transformation behavior of endosulfan in different environmental media and organisms is of great significance for the accurate identification and evaluation of the ecological risk surrounding the production site.In this study, one historical pesticide factory once producted large amount of endosulfan was selected as research area. More than 320 air, soil and biological samples surrounded the factory with different distances and in different seasons were collected for testing. Temporal and spatial characteristics as well as seasonal variations in soil-air exchange of endosulfan had been determined, and accumulation characteristics and ecological risks of organisms surrounding the study area had been revealed.The main results were shown as follows:(1) The atmospheric concentrations of endosulfan around the plant were 1.87～ 3.35 ng/m3 (on average 2.40 ng/m3) in autumn,1.47～4.52 ng/m3 (on average 2.48 ng/m3) in winter,0.28～1.46 ng/m3 (on average 0.93 ng/m3) in spring and 0.42～1.44 ng/m3 (on average 0.83 ng/m3) in summer. Compared with other areas, the concentrations of endosulfan in the study area were higher and mainly with a-endosulfan, which proved that this pesticide factory has produced some influence on surrounding air. Seasonal trends were found during the sampling campaign, with higher concentrations in winter and lower ones in spring and summer. The concentrations of endosulfan in the air decreased with the distance to the plant. The endosulfan inhalation risk evaluation showed that the inhalation risk of endosulfan to local residents was within the acceptable range, but the inhalation risk of children was higher than adults and with the increasing of distance, the inhalation risk decreased gradually.(2) The soil concentrations of endosulfan around the plant were 2.19～6.14 ng/g (mean 3.87 ng/g), which was higher compared with other area and the endosulfan sulfate was the main component. The influence of the plant on the surrounding soil is not significant compared with that on air. The concentrations of endosulfan in soil within 5km didn’t decrease obviously while presented obvious decreasing trend beyond 5km. Correlation research on endosulfan concentrations and TOC in soil showed that there was no obvious correlation between endosulfan and TOC, which indicated that the accumulation of endosulfan in soil may be affected by various factors.(3) Research on soil-air exchange showed that endosulfan had a tendency to be deposited from the air to the soil around the plant. The fugacity fraction (ff) value of endosulfan was smallest in winter and the ff value of a-endosulfan was the biggest. The annual average deposition rates of endosulfan were as following:a-endosulfan (0.13 ng/(m2d))<β-endosulfan (5.92 ng/(m2d))<endosulfan sulfate (7.84 ng/(m2d)), in which endosulfan sulfate was with biggest deposition amount. The deposition fluxes of endosulfan was the biggest in winter and the smallest in summer.(4) The average concentration of endosulfan in tree bark samples was 94.2 ng/g d.w. (59.2～126 ng/g d.w.), indicating that the long term average concentration of endosulfan in local air was relatively high and the composition of endosulfan was focusing on endosulfan sulfate. With the increase of distance, the concentrations of endosulfan in tree bark presented decreasing trend. The concentrations of endosulfan in rice was 7.36～35.5 ng/g d.w. (on average 17.4 ng/g d.w.), and endosulfan sulfate was the main contributor to the endosulfan congener pattern; the concentrations of wheat sample was 34.4-158 ng/g d.w. (on average 84.4 ng/g d.w.), and the main contributor to the endosulfan was β-endosulfan. The detection rate of endosulfan in rice and wheat was 100% and both concentrations were lower than Maximum Residue Limits (MRLs)of endosulfan in Japanese food.(5) The concentrations of endosulfan in animal samples showed an obvious trend as follows:butterfly> cabbage worm> locust> snail> earthworm> children> frog, in which the concentration range of endosulfan in insects was 18.6～170 ng/g d.w., on average of 75.1 ng/g d.w.; the average concentration of endosulfan in chicken was 27.5 ng/g d.w. (11.6～85.7 ng/g d.w.), which was bellow the MRLs of endosulfan for chicken in Japanese food. Further analysis of the accumulative level of endosulfan in chicken samples showed that the concentrations of endosulfan decreased in the order: chicken livers, chicken hearts, chicken meat and chicken gizzards, which indicated that endosulfan had the strongest accumulation ability in liver. The endosulfan congener patterns in animal samples were dominated by endosulfan sulfate. Compared with endosulfan levels in organism in other areas, the residue level of endosulfan in organism was higher in this study area. |
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