Pollution Characteristics And Risk Assessment Of Sulfonamides In Urban Drinking Water Sources

Sulfonamides?SAs?are the most widely used class of antibiotics and are commonly used in aquaculture,clinical medicine and daily life,and become a new type of pollutant.SAs are widely present in the water environment and are at a certain concentration level,and these pollutants can induce microbial resistance genes,which has certain effects on human health and safety and ecosystem stability,especially for drinking.Considering the trace level of SAs in drinking water source and it is very susceptible to matrix,this project is based on SPE-UPLC-TOF/MS to establish a suitable SAs detection method for drinking water sources,and for Hangzhou and Ningbo,Zhejiang Province.Pollution characteristics,sources and risks were evaluated by seven typical drinking water sources in Jiaxing city and Wenzhou city and 7 typical SAs in the river system of Hangzhou.The main results are as follows:?1?A method for simultaneous detection of 7 Sulfonamide antibiotics?SAs?in surface water based on solid phase extraction-ultra performance liquid chromatography-time of flight mass spectrometry.The analysis conditions were determined by optimizing the mobile phase and solid phase extraction conditions:the mobile phase was 0.1%formic acid aqueous solution?volume ratio?,the solid phase extraction was Oasis HLB column,the extraction system pH was 3,the loading flow rate was 4mL/min,methanol was used as the eluent.The detection limit of the method was 0.11⁰.21 ng/L.The linear relationship was good in 0.1⁰.500 ug/L,and the correlation coefficient was above 0.9900.The blank recovery rates of the target antibiotics in the water samples at the spiked concentrations of 4 ng/L,100 ng/L and 200 ng/L were:81.80%¹15.00%,89.46%¹20.35%,and 83.07%¹32.87%,respectively.The relative standard deviation?RSD?ranged from 5.07%⁷.63%,1.45%⁵.04%and1.87%⁷.18%.The results show that the method has high accuracy,precision,reproducibility and sensitivity,and can be used in actual water sample.?2?Analysis of pollution characteristics of SAs in drinking water sources in Hangzhou,Ningbo,Jiaxing and Wenzhou,Zhejiang Province:The detection rate of SAs in Hangzhou ranged from 60%to 100%,and the concentration range was ND¹3.12ng/L;Ningbo The detection rate of SAs in the city ranged from 80%to 100%,and the concentration ranged from ND to 8.55 ng/L.The detection rate of SAs in Jiaxing city ranged from 60%to 100%,and the concentration ranged from ND to 10.68 ng/L;The detection rate of SAs in the Wenzhou ranged from 80%to 100%,and the concentration ranged from ND to 7.08 ng/L.The average concentration of SAs was the highest in Jiaxing?17.90±5.23 ng/L?,followed by Hangzhou?8.68±7.78 ng/L?and Ningbo?8.51±5.61 ng/L?,Wenzhou?6.98±1.07 ng/L?is lowest;SM₂ and SMX are the most frequently detected antibiotics in drinking water source samples;The lake-type drinking water source should be chosen as the daily source of water for residents.According to the detection of mid-autumn and winter water samples in an inland river in Hangzhou,it is found that:SMT,SIX,SM₂,SD,SMR,SMX and SP were detected in an inland river in the fall,the concentration ranged from ND to 29.64 ng/L,SP was the main contaminated antibiotic;only SMT,SM₂ were detected in winter.SD,SMX and SP,the concentration range is ND²7.80 ng/L,SMX is the main contaminated antibiotics.There was no significant difference in antibiotic concentrations in autumn and winter,but the main types of contaminated antibiotics have changed.?3?The risk entropy value?RQ_s?method was used to evaluate the risk of drinking water sources and an inland river in Hangzhou.The results of the ecological risk assessment show:The SMX of drinking water source is 0.01<RQ_s<1,which has low or medium risk.The SM₂ of Hangzhou Jiuxi Water Plant is at 0.01<RQs<0.1,showing low risk;the RQ_s of SMX in autumn and winter inland water are between 0.1and 1.which has moderate risk,the RQ_s of the inland water sample SM₂ in autumn is0.01<RQ_s<0.1,which has low risk;SMX in both drinking water sources and inland water samples shows moderate ecological risk and needs attention.The results of the health risk assessment show:the RQ_H of SD,SM₂ and SMX in drinking water sources and in the inland rivers of Hangzhou were 2.1 e^-91.0 e^-7?1.9 e^-92.6 e^-77 and 4.7 e^-96.9 e^-8?1.2 e^-81.7 e^-7,respectively.the human health risk index is lower than the relevant foreign standards and does not show obvious risks.