Spatiotemporal variation and source analysis of agricultural non-point source pollution in autumn and winter in Zengcheng small watershed of Guangzhou
In order to analyze the spatio-temporal variation characteristics and pollution sources of water quality indexes in typical basins,this study focused on a typical agricultural non-point source pollution monitoring area in Zengcheng District,where water quality and quantity at the entry and exit points were systematically monitored from October to December 2023.The preliminary results identified the spatiotemporal patterns and pollution sources.The results showed that the average concentrations of TN,NH3-N,and TP in the water followed the pattern:inlet i-01>outlet o-01>inlet i-02.This may be related to extensive agricultural activities around i-01 and o-01.During rainfall periods,the concentrations of TN,TP and COD were generally lower than during non-rainfall periods,indicating the dilution effect of rainfall.There were significant positive correlations between TN and TP,TN and NH-3-N,and TP and NH3-N(R2=0.22～0.77),suggesting similar pollution sources for these indicators.Additionally,TP positively correlated with flow rate(R2=0.31),suggesting that increased flow due to rainfall carries pollutants from surrounding farmland into the water body.The preliminary exploration results of nitrate nitrogen and oxygen isotopes in water further indicated that the main sources of nitrate nitrogen in the monitoring area were soil nitrogen(35.6% )and domestic sewage(30.7% ),followed by soil fertilizers(25.3% ).
agricultural non-point source pollutionsmall watershedspatiotemporal variationsource apportionmentnitrogen and oxygen isotopes
万方数据
维普
