Investigation And Analysis Of Endocrine Disrupting Chemicals In Drinking Water In Guangzhou

ObjectiveTo investigate the status of pollution of endocrine disrupting chemicals(EDCs) in drinking water, while to evaluate the effect of EDCs removing of water treatment process of municipal waterworks, in order to provide the scientific basis for waterworks to improve the water treatment process.MethodsTo get all the municipal waterworks as research object, investigating the water treatment process of seven municipal waterworks and the status of water supply. The source water samples(n=28), finished water samples(n=28) and tap water samples(n=28)from seven municipal waterworks were sampled in dry season, spring, wet season and autumn in 2014. The bisphenal A(BPA), 4-nonylphenol(4-NP), 4-tert octyl phenol(4-t-op),diethyl phthalate(DEP), dibuty phthalate(DBP), oestrone(E1), estradiol(E2) and estriol(E3) in water samples were determined by GC/MS. Epidata3.1 and SPSS20.0 software were used for data input and analysis separately. The statistic methods of descriptive statistics, one-way ANOVA and multiple comparisons(LSD) were conducted.Results1. The source water was mainly from east river, north river and west river of the pearl river basin. The qualified rate of drinking water was better and better in recent years.At present, there were three kinks of water treatment process in municipal waterworks,the first is “coagulation-sedimentation-filtration-chlorination” process, namely conventional process; the second is “biological aerated filter-conventional watertreatment” process, namely biological pretreatment process; the third is “ozone-biological activated carbon” process, namely advanced process.2. The BPA, 4-NP, 4-t-OP, DEP, DBP, E1, E2 and E3 can be found in drinking water,the detectable rate of DEP, DBP and E2 were 100% in source water, finished water and tap water samples; the detectable rate of BPA was 100% in source water and finished water samples; the detectable rate of BPA was 96.42% in tap water samples; the detectable rate of E3 in source water, finished water and tap water samples were 57.14%,75.00% and 71.43% separately.The concentrations of BPA, 4-NP, 4-t-OP, DEP, DBP, E1, E2 and E3 in source water samples were: 0.91~11.05, ND~1.06, ND~9.12, 3.98~66.68, 4.04~90.09, ND~33.71, 7.09~89.72, ND~6.65μg/L; in finished water samples were: 0.06~5.67, ND~1.56, ND ~ 6.39, 5.64 ~ 41.03, 17.76 ~ 124.29, 0.01 ~ 18.32, 1.12 ~ 30.21, ND ~1.15μg/L; in tap water samples were: ND~4.67, ND~1.42, ND~5.39, 8.26~48.23,25.21~111.10, ND~18.02, 1.52~27.48, ND~1.18μg/L. The concentrations of EDCs in a part of finished water and tap water samples were greater than the source water, the concentrations of EDCs in a part of tap water samples were greater than the finished water samples.The DBP in all the source water, finished water and tap water samples were not qualified, the BPA and DEP in finished water and tap water samples were detected without over standard.3. The concentrations of DBP in east river was lower than north river and west river,the concentrations of other EDCs were indistinctive(P<0.01).4. The concentrations of EDCs in source water and finished water samples were different on seasonal variation(P<0.05). The concentrations of BPA of source water in wet season was lower than dry season and autumn(P<0.01), the concentrations of 4-NP of source water in spring and wet season was lower than dry season(P<0.01); the concentrations of E2 of finished water in wet season was lower than dry season and autumn(P<0.05); The concentrations of EDCs of tap water were indistinctive on seasonal variation.5. The concentrations of BPA, 4-t-OP, E1, E2 and E3 of finished water and tap water samples were lower than the source water samples(P<0.01); the concentrations of DBPof finished water and tap water samples were greater than the source water samples(P<0.001); the concentrations of eight kinds of EDCs in finished water and tap water samples were indistinctive.6. The removal rate of EDCs in water treatment process of all the municipal waterworks were: 69.95%(E2), 59.98%(4-t-OP), 56.39%(E1), 54.25%(BPA),54.21%(E3), 19.15%(4-NP), while the removal efficiency of DEP and DBP were very limited, the removal rate of DEP in water treatment process of waterworks A and waterworks D was: 0.44%, 36.55%, the removal rate of DBP in water treatment process of water works C was 37.10%, and the other municipal waterworks can’t remove the DEP and DBP.The removal efficiency of BPA and DBP was different among municipal waterworks(P<0.05), the water treatment process of waterworks A is advanced process, and its removal efficiency of BPA was better; the water treatment process of waterworks G is biological pretreatment process, and its removal efficiency of BPA was better; the water treatment process of waterworks C is conventional process, and its removal efficiency of DBP was better.7. The removal rate of BPA, 4-NP, 4-t-OP, E1 and E3 of advanced process were greater than the biological pretreatment and conventional process; the removal rate of BPA, 4-NP, E1 and E2 of biological pretreatment process were greater than the conventional process; the removal rate of E2 of conventional process was greater than the advanced process, and the removal rate of E3 was greater than the biological pretreatment process.The removal efficiency of BPA and 4-NP were distinctive on three kinds of water treatment process(P<0.05), and the removal efficiency of BPA and 4-NP of advanced process were better than the conventional process; the removal efficiency of BPA of biological pretreatment process was better than the conventional process.ConclusionsThe BPA, 4-NP, 4-t-OP, DEP, DBP, E1, E2 and E3 can be found in drinking water, in which that the concentrations of DBP in all the source water, finished water and tap water samples were not qualified, so, we should further strengthening the monitoring of DBP indrinking water, and find the main reason of disqualification. The water treatment process of BPA, 4-NP, 4-t-OP, E1, E2 and E3 removal were limited, most municipal waterworks can’t remove the DEP and DBP. The removal efficiency of BPA and 4-NP of advanced process were better than the conventional process; the removal efficiency of BPA of biological pretreatment process was better than the conventional process, and the mainly water treatment process of municipal waterworks is conventional process, so must research and improve the water treatment process promptly, especially optimize the conventional process, to enhance the the removal efficiency of EDCs of drinking water.