Distribution Of Contaminants In Soil And Groundwater At A Landfill

Groundwater is the fundamental nature resource for human survival and development.In recent years,with the development of economic and the rapid growth of population,the speed and scale of the consumption of water resources are very worrying.In to the increasingly prominent contradiction between the supply and demand of water resources at the same time,,the quality of surface water and groundwater is becoming increasingly serious due to the anthropic activities.These problems seriously hampered the social development,Which has attracted much more attention both at home and abroad.Garbage landfill is high priority applied in Beijing as a city garbage treatment method.Abandoned rivers and gravel pits are commonly used as the landfill places in suburban and rural areas of Beijing,.More than most of the backfill garbage are directly disposed in gravel pits without any standard treatment.The bottom and sides of gravel pit are also hardly taken laid impervious layer protective measures,which means that the infiltratfon of these backfill wastes as a potential sourse will seriously affect the groundwater quality.In this paper,a gravel pit landfilled construction wastes is chosen as the studied site in the western suburbs of Beijing.Many methods are used to determine the main pollutants and its spatial distribution,pathways and source in soil and groundwater,which include filed investigation,drilling exploration,shallow soil gas measurements,groundwater and soil samples collection,solid waste immersion test and other laboratory testing and analysis.The main conclusions are obtained as follows:(1)The pollutant components in groundwater and soil exist spatial differences in the study area.Some inorganic,heavy metals and organic components exceed the third standard of The Groundwater Quality Standards'(GB/T 14848-1993).The variation tendency of contaminants in backfill soil waste is different along with the change of burial depths.(2)Pesticides organic components are detected in groundwater at the west side of the park nursery garden and gravel pit,which probably result from the agricultural activities in the study area.(3)The backfill waste is one of the pollution sources.Fe,Mn,Zn,Pb,Cr and other heavy metals were detected all over the area,and concentrations are higher than the background values of Beijing.The strong vanation of petroleum contaminants,ammonia,phosphate,toluene and ethylbenzene etc.,are mainly caused by human influences.(4)The migration pathways of pollutants in the study area can be summarized as follows:upper groundwater inflow carrying the contaminants moved into the study area;the pollutants migrate to the groundwater table promoted by precipitating and leaching with gravity;new sources of pollution increased by human activities.