| The undefiled water is the foundation of public health. Though the toxic organic pollutants are trace quantity in aquatic system, they cause potential hazardous effects on human health because of their high degree of biocumulatiori and carcinogenic. These pollutants come not only from the point and non-point pollution, but the chlorine disinfectant process for drinking water also. At first, an aquatic research was made on the trace quantity organic pollutants of Yongding River which provide water mainly for southwest of Beijing city. The samples were collected in July 1999, the pollutants in water samples were concentrated with Amberlite XAD-2 resin column extraction while the sediment samples were conducted with freezing dryer and Soxhlet. The pretreated samples were analyzed by Ames test for mutagenicity,then by GO/MS using SIM mode and GC/ECD for qualitative and quantitative analysis. The results indicate that the Yongding River has been polluted to some degree, no mutagenicy could be observed in the static water (the Guanting Reservoir dam and Sanjiadian pool) however. The flow water (Bahaoqiao and Yanchi) showed greater mutagenic effect compared with static water and the strongest effect was oE~erved in Bahaoqiao at the uppest stream. The mutagenicity of sediment samples showed the trend almost opposite to the result of surface water, positive result was obtained in all samples except for the sample of Yanchi in the test of TAIOO. The total amount of pollutants in water decrease gradually downstream from Bahaoqiao, only the concentration of substituted benzenes is consistent with the Ames test. The lowest quantity of pollutants was detected in the sediment sample of Yanchi, but the sample of Sanjiadian showed the h~hest level downstream. In general, the quantity of pollutants in sediment in static water was higher than that in flow water, this was accordant with the mutagenitic test and demonstrated that the reservoir had become the depot of pollutants and caused contamination to the downstream area. The quantity of both PCBs and chlorinated insecticides was higher in the sediment of Bahaoqiao, more attention should pay to such situation. In addition, the samples collected from Beijing No.9 water work and iii concentrated with Amberlite XAD-2.4.7 mixed resin column were tested to assess the genotoxicity and acute toxociity during the processes of water treatment. The water work provides more than half of the drinking water of Beijing city now. The result indicates that the mutagenicity of source water in Beijing related to the seasonal variation. The organic substances content of source water collected in the low-water periods was higher than that in high- water periods, this caused the increase of chlorinated organic contaminants after chlorination and much greater mutagenic effect. The reason of the addition of coagulant caused the increase of mutagenic effect maybe is that the coagulant has no capacity of removing mutagens with low molecular weight (<2000Dal). Meanwhile, the addition of coagulant may result in the formation of more stable complexes between metal ions and humic acid substances and the release of mutagnens of low molecular weight which were originally combined with humic acid substances. Sand filtration and carbon filtration can remove the mutagens effectively, but the mutagenic effect of low- water periodical sample was raised up after carbon filtration and affected the...
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