Quantitative Study On The Source Tracing Of Agricultural Non-point Pollution In Wangbeng Area Of Huaihe River Basin

Agricultural non-point pollution is one of the main environmental problems in China.In this paper,the source of pollutants in the Huaihe River Basin was traced by stable isotope analysis,UV visible absorption spectrum and three-dimensional fluorescence spectrum.Monte Carlo water quality assessment model,MCMC mixed model of bistable isotopes,DOM peak searching method and parallel factor method model are used.The transfer characteristics of organic pollutants in farmland under different conditions were studied by the experiment of straw returning to the field.The results of the experiment were tested by the method of multivariate linear statistics,and the following conclusions were obtained(1)NO3--N in surface water of wangbeng area of Huaihe River Basin is the main form of TN,and it is the main index affecting the water quality of wangbeng area.The main pollution sources of NO3--N in wangbeng area of Huaihe River Basin are feces and domestic sewage(31.8%),followed by cultivated land soil(30.40%)and fertilizer(25.92%),and the rainwater contribution is the least(11.87%)。(2)The UV visible absorption spectrum characteristic parameters A(254),E2/E3,E4/E6,Sr,R(A,T),R(C,A)and R(C,T)have obvious spatial changes in Chengdong lake and Nihe.The fluorescence spectrum characteristic index(FI,Bix,Hix and freshness index)shows that dom of Chengdong lake has both humic and self-generated characteristics,among which the characteristics of self-source are more obvious,mainly because there are few residents around Chengdong lake,good water quality and strong self purification and no large amount of external input.The main reason is that the river channel of Nihe is narrow,the farmland is mostly large,the fish pond and livestock breeding point are more,and there are a lot of external input.(3)The main pollution sources of Chengdong lake and Nihe are fertilizer,domestic sewage,feces and cultivated land soil.The contribution rate of rainwater in Chengdong lake is 12.89%,and the contribution rate of mud river is the main agricultural non-point pollution,and the contribution rate of pollution source accounts for 75.63%.The model of parallel factors was established by Dom data,and the four component organic pollutants(rich acid C1,tryptophan C2,humic acid C3 and tyrosine C4)were obtained.(4)The main pollutants in the experimental field are straw,cultivated land,domestic sewage,fertilizer and feces through stable isotope tracing of 13C and 15N.The contribution rate of straw source increases with the increase of time,and the fertilizer also increases with the increase of time.The cultivated land soil and domestic sewage are taken away by the flow of soil due to snowfall,and the feces are decomposed and released first,and then the subsequent pollutants are released The contribution rate of the soil was decreased.The model of parallel factors was established by Dom data.It was found that there were two kinds of four component organic pollutants(like humic and protein like)in five pollution sources(rich acid Cl,tryptophan C2,humic acid C3 and tyrosine C4).Figure[82]Table[14]References[98]...