Pollution Characteristics And Control Of PPCPs In Rainfall Runoff In Urban Environment

In this study,the sampling and analysis of different functional areas and rivers in urban watersheds were carried out.We analyzed the accumulative characteristics of pharmaceuticals and personal care products(PPCPs)in different functional areas of the city and the output loads to the receiving waters,investigated the influence of rainfall runoff on the temporal and spatial distribution of PPCPs in urban rivers,discussed the efficiency of LID facilities for urban road runoff pollution control,and finally put forward the pollution control strategy of non-point source PPCPs into rivers.The results showed that the dominant PPCPs on urban road surface were anti-inflammatory antipyretic analgesics(naproxen,ibuprofen),estrogen(estrone,estradiol,estriol,ethinylestradiol),fluoroquinolones antibiotics(norfloxacin,ofloxacin,ciprofloxacin),macrolide antibiotics(dehydrated erythromycin,roxithromycin,clarithromycin)and stimulant(caffeine).The accumulative characteristics of PPCPs in different functional areas were various.The concentration of PPCPs adsorbed by road dusts was highest in residential area(3558.3 ng/g)and the content of PPCPs in hospital surroundings(1728.1 ng/m~2)ranked the first among the five functional areas.Estrogen,macrolide antibiotics and fluoroquinolones antibiotics posed high ecological risk to urban typical rivers in both rainy season and dry season.During the rainy season the concentration of PPCPs in typical rivers fluctuated greatly which was higher than that during the dry season on the whole.The increase of PPCPs concentration in the rainy season may be due to the pollution by the urban road runoff or serious pollution caused by the CSOs.The concentration of PPCPs changed gently along Xixiang River,but the concentration of PPCPs increased significantly in the middle and lower reaches of Xinzhen River especially during the rainy season,implying that PPCPs pollution in Xinzhen River was affected by the surroundings greatly and possibly CSOs occurred during the rainy season in the middle and lower reaches of Xinzhen River.As for the PPCPs into the receiving waters,the annual contribution rate of urban road runoff was only 1.6%compared with point source pollution,but the contribution rate during a rainfall event was as high as 30.2%,indicating that the short-term effects of urban road runoff pollution on the receiving waters should be paid attention to.Rain gardens,permeable pavements and rain wetlands could effectively control PPCPs pollution,especially the control rate of the target PPCPs in grass bricks was up to 75.0%-100%.Similarly estrogen,macrolide antibiotics and fluoroquinolones antibiotics showed high ecological risk in the urban road runoff,which could be completely controlled by the rain wetlands.Finally we put forward the prevention and control strategy of"source reduction+process control+end control"for PPCPs in urban road runoff.