Characteristics And Source Analysis Of Heavy Metal Pollution Of Road Runoff In Different Functional Areas Of Lin'an

An investigation was carried out in an attempt to reveal the characteristics of heavy metals contamination in the road runoff of Lin'an.Eight runoff samples were collected in seven sites from 2017 to 2018,and the concentions of Cu,Zn,Pb,Cr,Ni in the runoff samples of different functional zones were analyzed.The effects of seasonal changes,rainfall types,road conditions and road sediments on heavy metal contamination characteristics were analyzed.The principal component analysis was applied to identify the key pollution factors and sources of runoff water.Cluster analysis technique was used to analyze the spatial variations of the pollution level.The runoff pollution load was estimated.The results showed that:The degree of runoff pollution in different functional areas of Lin'an was different.The average concentration of Cu,Zn and Pb in the industrial area was the highest,and the average concentration of Cr and Ni in the traffic area was the highest.Compared with other cities,the concentration of runoff pollutants in Linan was higher.Affected by rainfall and road surface conditions,the greater the rainfall and the larger the attachment area of the road,the faster the concentration of heavy metals decreases and the lower the final concentration.Influenced by the air quality before the rainfall and the dust deposition of the atmosphere,the runoff showed the concentration of Cu in summer,spring was greater than in autumn and winter,the concentration of Zn,Cr in winter and autumn was greater than in spring and summer,and the concentration of Pb,Ni in winter and spring was-greater than in summer and autumn.The heavy metal content in road sediments in Lin'an was high,and it had a certain correlation with heavy metal pollution with road runoff.The key pollution factors and their sources of runoff in Lin'an were different.Principal component analysis showed that in the runoff of Lin'an,Cu and Zn mainly originated from industrial activities,Cr and Ni mainly originated from traffic activities,and Pb was affected by industrial activities and traffic activities.Cluster analysis showed that the pollution degree in industrial areas was heavier,the pollution degree in traffic areas and commercial areas was moderate,and the pollution degree in cultural and educational areas and residential areas was relatively light.The runoff pollution load of different functional areas in Lin'an were different.The SCS model and concentration method were used to estimate the runoff pollution load in Lin'an.The pollution load of different functional areas was in turn:industrial zone>traffic zone>commercial zone>residential zone>culture and education zone.Among them,the pollution load of Pb and Cr in industrial area,the pollution load of Pb,Cr and Ni in traffic area and commercial area exceed the pollution load based on Class ? standard of surface water(3838-2002).It was recommended to reduce the runoff pollution load by reducing pollution source generation,optimizing pollution discharge route,and doing end-of-flow treatment.