Nitrogen and phosphorus pollution characteristics and eutrophication risk assessment of urban lake reservoir type drinking water sources in Qiandongnan Prefecture,Guizhou Province
18 urban lake and reservoir type drinking water sources in Qiandongnan Prefecture,Guizhou Province were selected as the research object.The pollution characteristics of nitrogen and phosphorus in urban lake and reservoir type drinking water sources in Qiandongnan Prefecture were elaborated through water quality monitoring during dry,wet,and normal water periods.The comprehensive nutri-tional status index method was used to evaluate the eutrophication risk of their water bodies.The results showed that the average concentration of total nitrogen in urban lake reservoir type drinking water sources in Qiandongnan Prefecture was 0.76 mg/L,with nitrate accounting for 70.0%;The average concentration of total phosphorus was undetected,with soluble phosphate accounting for 80.5%.The spatio-temporal distribution characteristics of nitrogen and phosphorus in urban lake type drinking water sources in Qiandongnan Prefecture are obvious.The concentration of total nitrogen and nitrate is basi-cally consistent with the change of water period,while the overall change of ammonia nitrogen is not significant;The concentrations of total phosphorus and soluble phosphate are basically consistent with the changes in water period.By using Pearson's bilateral test in SPSS Statistics 19.0 to test the correla-tion between pollution factors,only CODMn and Chl-a showed a significant positive correlation during dry,wet,and normal water periods.The comprehensive nutritional status index method was used to eval-uate the drinking water sources of urban lake and reservoirs in Qiandongnan Prefecture,with poor nutri-tion accounting for 66.7%and moderate nutrition accounting for 33.3%during the dry season;Poor nutrition accounts for 50.0%and moderate nutrition accounts for 50.0%during the abundant water period;Poor nutrition accounts for 38.9%and moderate nutrition accounts for 61.1%during the nor-mal water period.The degree of eutrophication risk is ranked from high to low in the normal water peri-od,high water period,and low water period.Through in-depth analysis by using nitrogen phosphorus concentration ratio(TN/TP),it was found that the main limiting factor for water source nutrients is phosphorus limitation.Controlling phosphorus pollution is an effective way to prevent eutrophication in the water source of lakes and reservoirs in Qiandongnan Prefecture.
urban lake reservoir type drinking water sourcenitrogenphosphoruseutrophication risk assessment
NETL
NSTL
万方数据
维普
