太湖流域河网4种典型抗生素的时空分布和风险评价

分析了太湖流域人口密度大且养殖业发达的宜溧-洮滆水系水相和沉积相中典型抗生素磺胺甲恶唑(Sulfamethoxazole,SMX)、氧氟沙星(Ofloxacin,OFL)、罗红霉素(Roxithromycin,ROM)和土霉素(Oxytetracycline,OTC)的时空分布特征,并应用商值法进行了健康风险(Health Quotients,HQs)和生态风险(Risk Quotients,RQs)评价.结果表明,宜溧-洮滆水系中OTC、ROM、OFL、SMX在水相的检出率分别为96.5%、57.0%、60.5%和4.5%,沉积相中的检出率分别为96.5%、95.5%、90.0%和44.5%;水相检出浓度最高的抗生素为OTC,最高浓度为17.85 ng·L~(-1);沉积相检出浓度最高的抗生素为SMX,浓度为46.74 ng·g~(-1);相比于其他3种抗生素,流域水相和沉积相中OTC的检出率和检出浓度均较高.宜溧-洮滆水系主要包括南河和长江客水区,丰水期南河水系抗生素的检出水平高于长江客水区.沉积相中抗生素浓度沿水流方向逐渐降低,入湖河口所有点位由于沉积物堆积作用均呈现抗生素富集现象.渔业养殖中抗生素的大量施用是导致该水系抗生素时空分布差异的主要原因.健康风险评价结果表明,4种抗生素均属于可接受风险(HQs0.01).生态风险评价结果表明,4种抗生素均呈现低风险(RQs0.1),其中,生态风险最高的抗生素是OTC,其值为0.086.为有效管控太湖流域抗生素生态风险,应加强对南河水系水产养殖业监管;入湖河口的抗生素富集现象也应引起重视.

Spatial-temporal distribution and risk evaluation of four typical antibiotics in river networks of Taihu Lake Basin

The temporal and spatial distributions of four typical antibiotics Sulfamethoxazole (SMX), Ofloxacin (OFL), Roxithromycin (ROM), and Oxytetracycline (OTC), in aqueous and sedimentary phases of the river networks of Taihu Lake Basin were investigated. The human health and ecological risks were evaluated using quotient method. Results showed that the detection rates of OTC, ROM, OFL, and SMX in aqueous phases of the Taihu Lake Basin were 96.5%, 57.0%, 60.5%, and 4.5%, respectively. The detection rates of OTC, ROM, OFL, and SMX in sedimentary phases of the basin were 96.5%, 95.5%, 90.0%, and 44.5%, respectively. OTC had the highest concentration of 17.85 ng·L^-1 in aqueous phase, while SMX had the highest concentration of 46.74 ng·g^-1 in sedimentary phase. The detection rate and concentration of OTC in aqueous and sedimentary phases were higher than that of the other three antibiotics. The complex river networks in the Taihu Lake basin mainly includes the Nanhe river and the upstream of the Yangtze river. The concentration of antibiotics in the Nanhe River is higher in flood period but lower in dry period in comparison with that of in the upstream of the Yangtze River. The antibiotic concentration decreased gradually along the flow direction in sedimentary phases. The enrichment of antibiotics due to sediment accumulation was detected in all inlets of the Taihu Lake. The spatial distribution of the antibiotics was due to the aquaculture in this area. The results suggest an acceptable human health risk (HQs<0.01) and low ecological risk (RQs<0.1) of the four antibiotics in Taihu Lake Basin, while the ecological risk of OTC is relatively higher (RQs=0.086). In order to effectively control the ecological risk of antibiotics in the complex river networks in the Taihu Lake Basin, the supervision of aquaculture in the Nanhe River should be strengthened. Meanwhile, more attention should be paid to the enrichment of antibiotics in the inflows of the Taihu Lake.