Pollutant Characteristics And Remote Sensing Identification Of Typical Black And Odorous Water Bodies In Shenyang

In recent years,as the size of cities in our country has been expanding,the discharge of urban sewage has increased rapidly,resulting in a large area of urban black-and-odour bodies.In this paper,5 typical black and odorous water bodies in Northeast China were selected for study.The water quality indexes and the nutrients space distribution features of black and odorous water bodies were analyzed.Excitation-emission matrix?EEM?fluorescence spectroscopy combined with parallel factor analysis?PARAFAC?and UV-visible absorption spectroscopy were employed to analysis the components,humification degree and source of dissolved organic matter?DOM?.The correlation between DOM and AOPs?apparent optical properties??IOPs?inherent optical properties?was found by combining satellite remote sensing.The study reached the following conclusion:?1?Through water quality analysis,it was found that there are significant differences about the five black and odorous water bodies in water quality,tributary I and II were serious black-odorous,whereas tributary III,IV and V were mild black-odorous.The results of principal component analysis?PCA?showed that the main cause of deterioration of river water quality was the discharge of industrial,agricultural wastewater and domestic sewage.The correlation of concentration between Chlorophyll-a and TN?TP in severe black and odorous rivers was poor,while the correlation in mildly rivers was a little better,but still lower than normal river.?2?The EEM analysis results showed that DOM was decomposed into three components by PARAFAC,including protein-like component C1?235,360?,fulvic-like component C2?220,430?and humic-like component C3?255,520?.Based on principal component analysis,C2 exhibited close positive correlations with COD_Cr,NH₄⁺-N,S^2-and TP,and good negative correlations with DO and transparency.C2 mainly derived from terrestrial organic matter.C2 had a better positive correlation with C3,indirectly proving that C2 and C3could originate microbial endogenous.The contribution of terrestrial organic matter was higher to the DOM of black and odorous water bodies.The level of organic aromatics,molecular weight and organic matter humification of mild black odor water body is higher than that of severe black odorous water.The reason of bad odor and color might be total suspended solid particulates,so on.?3?The results of remote sensing spectral analysis showed that the CDOM and ap absorption curves decreased with the increase of wavelength,and the spatial variation was obvious.The CDOM in mild black odor water was higher than that in severe black odor water,but the absorption coefficient was smaller compared with severe black.It is further indicated that concentration of suspended solids matters in severe black odorous water was higher,while the concentration of dissolved organic matter in mild black odorous water was higher.The IOPs?CDOM?had a better positive correlation with DOM,which all came from terrestrial organic matter and microbial endogenous.Compared with normal water bodies,black and odorous water had lower R_rs?Remote sensing reflectance?.Correlation analysis results showed that the relationship between R_rs and DOM was better,and the correlation of mild black odorous water was higher than that of severe black odorous water,in which the correlation between R_rs and tryptophan-like component was the largest,and there was no significant correlation with humic-like component.