珠江广州段水体抗生素的复合污染特征及其生态风险

Co-occurrence and Ecological Risk of Antibiotics in Surface Water of Guangzhou Section of Pearl River

抗生素被广泛用于人和动物的疾病治疗,使用后未完全吸收的抗生素随污水大量进入环境,其环境行为和生态效应引起了人们的广泛关注。珠江广州段流经珠三角经济发达区域,受到广州市生活污水及周边养殖废水污染。为了解珠江广州段抗生素污染状况,有必要系统监测其水体抗生素的污染水平,评价其生态风险,为珠江流域抗生素的管理和风险防控提供数据支撑。在2015年12月的枯水期和2016年4月的丰水期,对珠江广州段13个采样断面中41种抗生素化合物的含量水平和空间分布进行了研究,并对抗生素的生态风险进行了评价。枯水期检出18种抗生素化合物,含量范围为ND^642 ng?L^(-1),以脱水红霉素含量最高,其中有11种抗生素检出率达到100%;丰水期检出20种抗生素化合物,有9种抗生素检出率为100%,含量范围为ND^703 ng?L^(-1),以氧氟沙星含量最高。上游河段中抗生素化合物的质量浓度较低,城区人口密集区对应的水体中质量浓度较高,而石井河、猎德涌、沙河涌等市区河涌质量浓度最高。对其中13个检出的抗生素化合物进行生态风险评价,结果表明珠江广州段水体单个抗生素以脱水红霉素、罗红霉素和氧氟沙星生态风险较高,其中,脱水红霉素尤其显著。枯水期珠江广州段水体大多数监测断面脱水红霉素的风险商值大于1,其中,石井河口最高,达到6.23。总抗生素加和风险商值普遍较高,最高达到10.6,大部分断面总抗生素风险商属于高风险范围,需采取措施控制水体环境抗生素污染。

Antibiotics are widely applied as human and veterinary drugs for treatment of diseases.After being used,antibiotics are only absorbed partially by bodies of human and animals,and the residual antibiotics enter into wastewater treatment plants or facilities.Due to incomplete removal and constant discharge,large quantities of antibiotics are released into receiving water.Hence,the fate and adverse ecological effects of antibiotics in environment caused wide attentions by researchers and the publics.The Guangzhou section of Pearl River flows through the developed regions of the Pearl River Delta,where receive the discharge of domestic sewage from Guangzhou City and aquaculture wastewater from ambient towns.In order to learn the pollution characters of antibiotics in Guangzhou section of Pearl River,it is necessary to investigate the contamination of antibiotics in Guangzhou section of the Pearl River,and assess the ecological risk.Our research contribute to the risk control of antibiotics in the Pearl River Basin.During dry season(Dec.2015)and wet season(Apr.2016),investigation of the concentrations and special distribution of41antibiotics from13sampling sites were conducted,and the ecological risks posed by antibiotics to aquatic organisms were assessed.18antibiotics were detected in dry season,with the concentration range of ND^643ng?L-1and the maximum concentration for erythromycin-H2O.Among them,the detection frequencies of11antibiotics were100%.20antibiotics were detected in wet season,with the concentration range of ND^703ng?L-1and the maximum concentration for ofloxacin.Among them,the detection frequencies of9antibiotics were100%.The concentrations of antibiotics in sites of the upper reaches were generally lower than the concentrations in sites of urban population density area along the river,while the tributaries of Shijing River,Sha River and Liede River was detected the highest concentrations.For13single antibiotics,the risk assessment results showed that erythromycin-H2O,roxithromycin and ofloxacin displayed higher risks than others antibiotics.Especially,the risk posed by erythromycin-H2O was notable with the risk quotients(RQs)in most sites of dry season higher than1and the maximums RQ up to6.23in Shijing River.For the summed risk quotients of total antibiotics,the risks were high in most of sites in Guangzhou section of the Pearl River with the maximums RQ up to10.6,suggesting that the ecological risks of antibiotics in surface water of Guangzhou section of the Pearl River were at high levels.Further control measures are needed to reduce the contamination by antibiotics in the Guangzhou section of Pearl River.