Study On The Characteristics Of Surface Water Pollution And The Distribution Of Pollutants

The surface water of urban slow-flow rivers is an integral part of settlements and has important ecological functions,aesthetic values and economic significance.Pollutants cause pollution when they come into contact with water leading to abnormalities such as colour and odour,and often the sensory pleasure is poor.When certain characteristics of water cause people's sensory dissatisfaction,such as turbid water,abnormal water colour,black and odorous water,algal blooms water,etc.Most of the water function are lost,affecting both human life and environmental quality,then this phenomenon is called apparent pollution.By analysing the distribution pattern of characteristic pollutants in water and identifying the source,type and nature of the pollutants that lead to this characteristic,it is possible to control the formation of pollutants in water,and provide some guidance for surface water pollution control and water quality restoration.Therefore,the study selected the Su Zhou ancient city and related canal sections from November 2017 to March 2019 and a total of 29 sampling points were chosen.From the correlation between the apparent pollution and pollutants in the different types of water analysed,the molecular weight,three-dimensional fluorescence characteristics of dissolved organic matter in water and different apparent sources of pollutants were determined.The characteristic pollutants in organic dominant water were Im,UV₂₅₄,and sulphide.The water parameters were Im>9.93mg/L,UV₂₅₄>0.11cm^-1,S^2->0.1mg/L and DO<1.77mg/L.This water was found to have the highest DOM concentration,SUVA range from 0.6⁴.6 L·?m·mg?^-1,and the largest molecular proportion was>3KD most of which are derived from exogenously input aromatic proteins and some small molecule humus,and contribute to prolonged black colour and odour.The characteristic pollutants in inorganic dominant water were turbidity,Im/turbidity,90%inorganic dominant type Im<6mg/L,which was less contaminated by organic compounds.The Im/turbidity value of 90%inorganic-oriented water was<0.07mg·NTU/L,indicating contamination by inorganic substances.The lowest DOM concentration proportion was in the range of 1K³KDa.The humus is mainly derived from terrestrial sources and macromolecules are easily adsorbed by inorganic substances.Chl-a,NH₄⁺-N and TP in nutrient-dominant water are the main characteristic pollutants.More than 70%of the nutrient-predominant water the Chl-a was between25?g/L and 200?g/L.When“algal bloom”appeared,Chl-a>176?g/L,NH₄⁺-N>5.81mg/L,TP>1.04mg/L,>3KDa and<1KDa DOM accounted for about half of the total content of which<1KDa was mainly the photosynthesis of humic acid and fulvic acid produced by algae.Algae and other photosynthesis produced odorant2-MIB and GSM.2-MIB>GSM,algae to cyanobacteria?Nymphaea,dinoflagellate?and green algae?chlorella?dominated,and algae easily released 2-MIB.In the organic dominant type,when the proportion of macromolecules decreased and the proportion of small molecules increased,the water was classified as nutrient-type water.In the nutrient-dominated water,when 10KDa and 3KDa macromolecules increase,the water maintains grayish-green and has the ability to transform into organic dominant water.This phenomenon is commonly found in rivers within residential areas where domestic sewage is directly discharged.