Contaminative conditions of main rivers flowing into the sea and their effect on seashore of Qinhuangdao

In order to study pollution conditions、trophic state and pollutant fluxes of main rivers flowing into the sea and their effect on seashore,the data of hydrology and water quality of the Yinma River、the Yanghe River、the Tanghe River and the Daihe River were collected.The results showed that the pollution of the Yinma River and the Yanghe River was worse than other rivers and the key pollutants of main rivers flowing into the sea were DIN、COD and PO43--P.According to the comprehensive trophic state index,the Tanghe River was light eutrophication,the Daihe River was moderate eutrophication and the Yanghe River and the Yinma River were extreme eutrophication.As a result,the eutrophic conditions of rivers flowing into the sea were very serious.The pollutants flux trend of main rivers basically decreased in recent years,but the amount of pollutants into the sea by the Yinma Rivers and the Yanghe River accounted for 94.91% of the pollutant amount flowing into sea from land.The correlation analysis showed that the water quality of the seashore was mainly affected by rivers flowing into the sea,especialy the index of CODMn、DIN and PO43--P had significantly correlation between river and sea.Therefore,the management for pollutans into river should be strenghened to improve the water quality of seashore,especialy the control of domestic wastewater and agricultural non-point pollution should be the key.