基于SWAT模型的小清河流域典型农药入海通量数值模拟研究OA

Pesticide pollution from non-point sources poses a threat to coastal ecosystems,yet accurate watershed models for estimating pesticide flux to the sea remain scarce.In this study,we applied the Soil and Water Assessment Tool(SWAT)to simulate the flux of typical pesticides into the sea in the Xiaoqing River Basin.Using multi-year hydrological observations and pesticide survey data from 2022-2023,we optimized key parameters related to pesticide transport and transformation.The model was calibrated and validated against measured date on the flux into the sea of atrazine,nicosulfuron,and chlorpyrifos.Results revealed a consistent decline in the flux into the sea of atrazine,nicosulfuron,and chlorpyrifos from 2013 to 2022,with total reductions of approximately 71%,69%,and 58%,respec-tively.By 2022,the estimated fluxes reached 166 kg for atrazine,1.30 kg for nicosulfuron,and 0.54 kg for chlorpyrifos.Seasonal variations in flux for all three pesticides displayed a bimodal pattern,with peaks in March and July.The bimodal patterns of the herbicides atrazine and nicosulfuron differed sig-nificantly(p<0.05),while that of the insecticide chlorpyrifos showed no significant difference(p>0.05).Spatially,pesticide fluxes were concentrated in flat,agricultural subbasins,forming distinct hotspots.The primary source areas of pesticide load to Laizhou Bay were identified as agricultural subbasins in Weifang City,Zibo City,Guangrao County(Dongying),and Zhangqiu City(Jinan).This study offers a sci-entific basis for managing non-point source pesticide pollution in the Xiaoqing River Basin.