| Objective To find out the intensity and variability of mutagenicity of raw water and drinking water which were collected from Taihu Lake and Yangtze River in Jiangsu province. The variation of disinfection by-products in the drinking water treatment processes and the relationship with water quality parameters were studied. Meanwhile, the health risk of disinfection by products was evaluated.Methods A total of 43 samples were collected from November 2014 to January 2016 in some areas of Jiangsu Province. Mutagenicity was tested by Ames test. The water quality parameter and disinfection byproducts were tested in the same period.Results1. A taotal of 6 samples were test by Ames test（TA98,±S9）, the positive ratio was 28.57%; Most of mutagenic matters in Yangtze River and Taihu Lake were frameshifes directly mutagenic compounds.while,there was no positive samples in raw and finished water from Taihu Lake.2. The disinfection byproduct in raw water was not detected. The concentration of DBPs in the finished water from Yangtze River ranged as follows: CF > BDCM > DCAA > DBCM. BF was not detected. But in Taihu Lake,the concentration of DBPs in the finished water ranged as follows: DBCM > BDCM > CF, BF > TCAA > BCAA. The THMs in the finished water from Yangtze River accounted for 63% of the total disinfection byproduct, HAAs only accounted for 37%; while The THMs in the finished water from Taihu Lake accounted for 93% of the total disinfection byproduct, HAAs only accounted for 7%.3. A total of 19 samples from Yangtze River were tested by Ames test, the positive ratio of drinking water from Yangtze River was 47.37%.The mutation ratio of finished water in Yangtze River was higher than raw water. A total of 42 samples from Taihu Lake were tested by Ames test, the positive ratio of drinking water from Taihu Lake was 28.57%.The mutation ratio of raw water from Taihu Lake was higher than finished water.4. The concentration of disinfection by-products in the collected water samples were not more than the national standard.THMs was rised during water treatment processes in all waterworks which take raw water from the Yangtze River and Taihu Lake,tap water>finished water >raw water. HAAs was rised during water treatment processes in waterworks which take raw water from the Yangtze River. HAAs in waterworks which supplied by Taihu Lake was firstly increased then decended, especially after the activated carbon filter process, the average value of the HAAs ranged from 9.79μg/L to1.01μg/L.5. In Yangtze River, THMs and turbidity, chromaticity, ammonia nitrogen, nitrite, chemical oxygen demand, Fe3+, residual chlorine presented correlation. HAAs presented correlation with turbidity, chloride, oxygen and chlorine.In Taihu Lake, THMs presented correlation with TOC, water temperature, chromaticity, p H, nitrite, ammonia nitrogen, chemical oxygen demand, dissolved oxygen, algae, UV254, total hardness, alkalinity; HAAs presented correlation with p H, nitrite, chemical oxygen demand, dissolved oxygen and UV254.6. The highest carcinogenic risk of disinfection byproducts to human in Yangtze River is TCAA(10.92×10-6). The level of carcinogenic risks of HAAs(13.48×10-6)was higher than THMs(10.93×10-6). The highest carcinogenic risk of disinfection byproducts to human in Taihu Lake is DBCM(15.34×10-6).The level of carcinogenic risks of THMs(31.25×10-6) was higher than HAAs(2.24×10-6).ConclusionOn the condition of this study, these conclusions can be drawn:1. The mutagenicity in the raw and finished water of the Yangtze River was higher than mutagenicity in the raw and finished water of Taihu Lake.2. Compared with Taihu Lake, the concentration of CF, DCAA, TCAA, HAAs in the finished water from Yangtze River was much higher, the concentration of DBCM, BF, THMs in the finished water from Yangtze River was much lower.3.The removal effienciy on mutants of water works A（Taihu lake） was more effective than that of waterworks B（Yangtze river）4. The trend of HAAs in the Yangtze River was generally rised, but in the Taihu Lake was firstly increased then decended. The THMs was rised slowly in the whole work.5. DBPs presented correlation with some water quality parameters. The correlation between MR and water quality parameter was not found.6. The main carcinogenic risk of disinfection byproducts to human in finished water from Yangtze River was contributed by HAAs. The main carcinogenic risk of disinfection byproducts to human in finished water from Taihu Lake was contributed by THMs. Total carcinogenic risk of disinfection byproducts ranged as follows: tap water（Taihu Lake）>finished water（Taihu Lake）>tap water（Yangtze River）>finished water（Yangtze River）. |
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