The Occurrence Characteristics Of Microplastics In The Changzhou Section Of The Beijing-Hangzhou Canal

Microplastics is an emerging pollutant in the environment,which have received extensive attention.Compared with the microplastics in the marine environment,there are still relatively few studies on the microplastics pollution of freshwater.At the same time,little is known about the microplastics pollution in sewage plant drains and their receiving water bodies and their influence on the distribution of microplastics in major rivers.This study choose Changzhou section of Beijing-Hangzhou Grand Canal as the main research object.Through developing device to collect and sort microplastic,optimizing the method to separate microplastics,we go on a preliminary investigation of the characteristics of microplastics pollution in surface water and sediment of Changzhou section of Beijing-Hangzhou Grand Canal,and made a research on the distribution of the microplastics in four of the sewage plant effluent and receiving waters in this basin.We discuss initially the influence of effluent from sewage plant on microplastic pollution in Changzhou section of Beijing-Hangzhou Grand Canal.The valuable reference information is provided about the condition of microplastics pollution in Changzhou section of Beijing-Hangzhou Grand Canal in terms of methodology and basic dataThe four sewage treatment plants in Changzhou section of Beijing-Hangzhou Grand Canal have a certain removal efficiency of microplastics(21.88?95.21%).The maximum abandunce of microplastics in the effluent of sewage treatment plants is 25±8 items/L,and the minimum is 8±6 items/L.In the shape of microplastics,the fiber is the main shape of the effluent from the four sewage treatment plants.However,in terms of the type of microplastics,polyester is the main component of the four wastewater treatment plants.In the receiving water body,the average abundance of microplastics in the surface water of the four section is showing descending order as reach QSY>ZQ>LS>QT,which is 22235,18937,12754,9703items/m~3,respectively.The abundance of microplastics in each section of the river showed that the abundance of microplastics in the adjacent water body of sewage plant outlet was lower than that in the upstream water body.In the aspect of shape,mainly fragments,but,the pellets accounted for the highest proportion in some points.In terms of particle size,particle size less than 300?m accounted for more than 50%of the total particle size.In terms of types,two types of microplastics,dimethyl carbonate and polybutyl acrylate,were found in the receiving water,but were not detected in the effluent from the sewage plant.However,methylsilane,methylamide,polypropyl ethylene,polyolefin,nylon,dimethyl carbonate and methyl nitropropionate,seven kinds of microplastics in the effluent of sewage treatment plant,were not found in the adjacent water body and downstream of sewage plant outlet.As the main river which the effluent from sewage treatment plant and the receiving water flow into,the abandunce of microplastics in the surface water of Changzhou section of Beijing-Hangzhou Grand Canal range from 12065 to 47283 items/m~3,and the microplastics with particle size less than 0.3 mm account for the largest proportion.In surface water,fibers and fragments are the two most abundant shapes.The main colors are white and blue.Polyethylene and acrylic are rich in surface water.The abundance in sediments ranged from508 to 2469 items/kg(Dry Weight,DW).Microplastics with particle size less than 0.3 mm were the majority.White and transparent microplastics were the most.Compared with other rivers and lakes,microplastics pollution in Changzhou section of Beijing-Hangzhou Grand Canal is more serious.The abundance of microplastics in the water near the wharf is high,which indicates that the ship may be one of the main reasons for the high microplastics pollution in the Changzhou section of Beijing-Hangzhou Grand Canal.In addition,the elevation of river bottom and the confluence of river may affect the abundance level of microplastics in sediments.The microplastics generated by the aging and fragmentation of building coatings may also enter the water body with rainwater runoff.The results of this single study show that the pollution of microplastics in Changzhou section of Beijing-Hangzhou Grand Canal is relatively serious.In addition,it still needs the follow-up to continue to pay attention to,and,carrying out in-depth research.