Analysis Of River Pollution Characteristics And Source Traceability Researches

There are various types of pollution sources in River,analyzing pollution characteristics helps to identify the occurrence and fate of pollution in the water body.Analysis of river pollution characteristics and source traceability researches are of great significance to river pollution control.To achieve the purpose of accurate source tracing,this study took the Ximing River in Nanning City as the research area,selected nitrate nitrogen and oxygen isotopes,and pharmaceuticals and personal care products(PPCPs)as indicators of traditional pollution and emerging pollution,discussed the pollution characteristics of the Ximing River,and conduct traceability analysis.The process of isotope-based traceability lacks the discussion of industrial pollution sources and cannot fully reflect the types of pollution sources.Therefore,the method of PPCPs was used to compensate the lack of isotopes and help the traceability results more accurate.After analyzing the pollution characteristics of the Ximing River,we qualitatively and quantitatively traced the source of pollutions.The results of the two methods are compared and analyzed with the current situation,in order to determine their applicability and effectiveness.Then we proposed a comprehensive traceability analysis method.The results can be applied to the water quality safety assurance work,which helps to focus on the actual sources during pollution controlling and improve the efficiency of pollution treatment.The main conclusions of this study are as follows:(1)The characteristics of nitrate pollution and traceability analysis based on nitrogen and oxygen isotopes found that the overall range of δ15N-NO3-and δ18O-NO3varies widely in different seasons,and the mixed pollution sources lead to pollution.Most of the isotopes originate from the lower δ15N-NO3-and higher δ18O-NO3-types of pollution,reflecting the pollution input from non-natural sources in the watershed.The traceability results showed that the nitrogen pollution in the Ximing River comes from the three major sources:fertilizer and ammonium from precipitation,manure sewage nitrogen,and soil nitrogen.In general,the contribution rate of chemical fertilizer nitrogen is the largest among all pollution sources,with an average contribution rate of 37.36%,followed by manure sewage nitrogen and soil nitrogen,with an average contribution rate of 30.42%and 15.32%,respectively.(2)According to the pollution characteristics analysis of target PPCPs,we found that the detection of target PPCPs differs in basins and regions.Comparing the concentrations of target PPCPs in 48 watersheds,it is found that 13 types of target PPCPs have aroused serious environmental pollution.The 3 types of target PPCPs with the highest detected concentrations in Ximing River were theophylline,methylparaben,and salicylic acid.The nutrient content and the water quality parameters are the key factors that affect PPCPs,and the target compounds are also related with each other.The traceability results show that there exists partly discharge of sewage in the watershed and nearly 60%of the pollution comes from the mixed influence of domestic and agricultural sources.Therefore,the pollution types of Ximing River are mainly from agricultural and domestic sources.(3)The two traceability methods come to basically the same result,indicating that agricultural and domestic sources are the main source of pollution in the study area.And the traceability results are consistent with the current pollution status.Both methods have their own advantages.The PPCPs-based pollution traceability method is more effective in qualitative classification,for its various sorts of types;the isotopebased pollution traceability method is more effective for quantitative analysis of the contribution rate.Therefore,integrated two methods of isotopes and PPCPs in the traceability process can help to classify the types of pollution sources more specifically,so as to achieve the purpose of accurate traceability.