Environmental fates of thiophosphate and triazole fungicides in a paddy-dominated basin.

Under the widespread use backgrounds of fungicides in paddy-dominated basin, the neglect of fungicide environmental fates may aggravate their pollution risks. By integrating field detection with model simulation, we quantified the loss loads and explored the environmental fates of one thiophosphate and five triazole fungicides. Based on the experimental results, we simulated fungicide loss loads with the coefficient of determination of the verification results greater than 0.5 (with p-value less than 0.01). The model simulation results revealed that the extensive distribution of paddy fields and the rough terrain in the lower reaches attributed to higher loss loads observed downstream than upstream. Meanwhile, the loss loads in study watershed concentrated from May to October, constituting 92.69 % of the annual total. A robust correlation between fungicide loss and precipitation (with the coefficient of determination greater than or equal to 0.51, p-value less than 0.01) underscores the pivotal role of rainfall in mediating fungicide migration. Transportation has emerged as the primary environmental behavior of fungicides, accounting for at least 92.87 % of the total flux. Furthermore, the results of field investigation showed the application pattern of fungicides also affected the spatial and temporal characteristics of fungicide loss and also the loss load. The combination of experiment and model revealed the migration and distribution patterns of fungicides in the paddy-dominated watershed, facilitating effective management at catchment scale.