Research On The Characteristics Of Environmental Pollution And Ecological Risk Assessment Of The Rivers

The characteristics of polluted river and ecological risk assessment of the typical pollutant have been one of the hot researches in the field of environmental engineering.It is very important to study the features of distribution of pollutants in the river,so that the current situation of polluted river is recognized and contamination treatment is easily done.Ecological risk assessment is an important means for assessing the possible adverse effects of pollutants on the ecological environment.Duliujianhe River,the largest river in the south of Haihe River System,connects the nature reserve Beidagang Wetland and the bird sanctuary Tuanbowa Wetland.It is of special ecological importance.However,in recent years,Duliujianhe River is heavily polluted and fragile ecological.Taking the Duliujianhe River as an example,this paper studied the pollution characteristics of rivers similar to reservoirs,which are characterized by small runoff,slow flow,poor self-purification capacity,small environmental capacity and easily emerging local pollution.This type of artificial rivers is common in the northern region of China.Furthermore,we assessed the ecological risk of the most serious pollutant in the water environment of Duliujianhe River applying the SSD model.Finally,according to the results of ecological risk assessment of the representative pollutant combined with the features of distribution of pollutants,we discussed the engineering measures for the reduction of typical pollutants preliminarily.The main conclusions of this paper were as follows:(1)The polluted features of water environment of Duliujianhe River is of complexity and locality.Organic pollution(COD,BOD,TOC,etc.),nitrogen and phosphorus pollution is in coexistence with heavy metal pollution.Overall,the pollution is still oxygen-consuming type.The pollution of Duliujianhe River has a closer relationship with local sources of pollution than the upper,middle and lower reaches of the basin.The pollution of Cd is the most serious polluted and the most harmful contaminant in Duliujianhe River.(2)The problem of the ecological risk assessment of heavily polluted water bodies applying the SSD model were it has high proportion of species tolerant to polluted water and the toxicity data of species is often not enough.The study showed that the data of species tolerant to polluted water has little impact on the construction of SSD curve as well as ecological risk assessment.What's more,when short of species toxicity data,historical species data can be used for supplement.The result of ecological risk assessment of Cd in Duliujianhe River water environment showed that the ecological risk of cadmium to Duliujianhe River was very high,which would harm about 18.1%aquatic organisms in the river.(3)The risk pollutants of Duliujianhe River can be reduced by ecological supplement of water and reconstruction project of surface flow wetland,which can reduce the potential impact proportion of Cd by 11%,eliminating the ecological risk of Cd as well as COD and TN in the Duliujianhe River.