某规模化猪场废水中抗生素污染特征及生态风险评估

Pollution characteristics and ecological risk assessment of antibiotics in wastewater from a large-scale piggery

为了解规模化养猪场废水中抗生素污染特征和生态风险,选取广东省某规模化养猪场,连续2 a于夏、冬两季采集饲料、不同处理阶段废水和鱼塘水,用UPLC-MS/MS法检测4类19种兽用抗生素,对比分析沼气池和曝气池对不同类型抗生素的去除效果,并采用风险商值法评价猪场经处理后废水和鱼塘水综合利用的生态风险。结果表明,猪饲料中仅检出四环素类(TCs)的4种抗生素,TCs浓度在1867~181050μg·kg^(-1)之间,土霉素(OTC)和金霉素(CTC)是猪饲料中主要添加抗生素;猪场原水中喹诺酮类(QLs)、磺胺类(SAs)和TCs抗生素浓度分别为1791.41、4144.28μg·L^(-1)和42393.81μg·L^(-1),未检出大环内酯类(MAs)抗生素,其中OTC单体浓度最高,其次为四环素(TC),分别为19555.70μg·L^(-1)和18654.86μg·L^(-1);处理后废水中MAs、QLs、SAs和TCs浓度分别为0.01、0.10、21.24μg·L^(-1)和388.02μg·L^(-1),单体浓度以OTC最高,为381.56μg·L^(-1)。沼气池对原水中QLs、SAs和TCs的去除率分别为91.9%、96.5%和18.8%,曝气池对沼液中QLs、SAs和TCs的去除率分别为99.9%、85.5%和98.9%。处理后废水向环境排放抗生素总量910.29μg·d^(-1)·pig^(-1),其中TCs占比达94.24%。风险商值评价结果显示,处理后废水中的恩诺沙星(ENR)、磺胺二甲嘧啶(SM2)、OTC和TC为猪场处理后废水中的高风险污染物,磺胺嘧啶(SDZ)为鱼塘水中高风险污染物。研究表明,规模化养猪场经处理后废水和接纳部分废水的鱼塘水中抗生素对环境仍有较高生态风险。

To understand the characteristics and ecological risk of wastewater produced by a large-scale piggery in Guangdong Province,19 antibiotics of the macrolides(MAs),quinolones(QLs),sulfonamides(SAs),tetracyclines(TCs)from pig feeds,untreated wastewater,treated wastewater,and associated fishpond water were detected using ultra-performance liquid chromatography-tandem mass spectrometry over two years.The efficiencies of wastewater treatment facilities were compared as well.The ecological risk of treated wastewater usage and associated fishpond water was assessed following the risk quotient(RQ)method.The results indicated that only four kinds of TCs were detected in pig feeds.The total concentration of TCs in feeds was approximately 1867~181050μg·kg^(-1),and oxytetracycline(OTC)and chlortetracycline(CTC)were dominant.Besides TCs,QLs and SAs were also detected in untreated wastewater,with average concentrations of 42393.81,1791.41μg·L^(-1),and 4144.28μg·L^(-1),respectively.Among these antibiotics,OTC and TC were dominant(19555.70μg·L^(-1)and 18654.86μg·L^(-1)).MAs,QLs,SAs,and TCs were detected in treated wastewater with mean concentrations of 0.01,0.10,21.24μg·L^(-1),and 388.02μg·L^(-1),respectively.Among these antibiotics,OTC recorded the highest concentration(381.56μg·L^(-1)).Additionally,our results also showed that both aerobic and anaerobic treatments could effectively degrade the QLs,SAs,and TCs residuals in wastewater.Compared with untreated wastewater,99.9%,85.5%,and 98.9%of QLs,SAs,and TCs were degraded by the aeration tank,whereas the biogas tank removed 91.9%,96.5%,and 18.8%of QLs,SAs,and TCs,respectively.After treatment,the total amount of antibiotic residuals discharged was 910.29μg·d^(-1)·pig^(-1),and TCs responded to 94.24%of the total residuals.RQ analysis showed that enrofloxacin,sulfadimidine,OTC,and TC were the primary high-risk pollutants in treated wastewater from the large-scale piggery,and sulfadiazine was the high-risk pollutant in fishpond water,suggesting that treated wastewater and fish pond water pose high ecological risks.