Research on the spatio-temporal variation of pollutant discharged from industrial wastewater in the Liaohe River Basin

Based on the method of equivalent standard pollution load,the trend of pollutant emission discharged by industrial wastewater in the Liaohe River Basin in Liaoning province during five typical years before and after the policies of Reform and Opening-up and the Industrial Structure Adjustment,was analyzed in terms of spatial characteristics of industrial pollution sources.Detailed discussions were put on the regularity of spatio-temporal variation of major pollutants.Data shows that industrial pollution sources in Liaohe River Basin mainly distribute along the expressway,in the city blocks in central Liaonig province and its coastal areas,and present a trend of unceasing focus.The total amounts of discharged industrial wastewater and the pollutants show a continuously decreasing trend.The main pollutants discharge in the Liaohe River Basin are COD,ammonia nitrogen,volatile phenol and petroleum oil,and the organic pollutant discharged by the industrial wastewater is more than that of inorganic pollutants.There is a big variance in heavy metal pollution with the main heavy metal pollutant of Hg during 1985-1999,Cr,Pb and Cd during 2002-2005,and Pb,As and Cr in 2008.There exists an obvious trend of pollutant discharge transfer in different regions because the main discharge regions of volatile phenol,petroleum oil,lead and arsenic vary completely during these years,although there is no obvious change in the main discharge regions of COD,ammonia nitrogen discharge.