China-PEARL和PRZM-GW模型潍坊市场景农药地下水风险评估研究

农药地下水暴露模型China-PEARL已开始在我国农药地下水风险评估中应用。本文利用China-PEARL潍坊市场景数据,为PRZM-GW构建了潍坊市场景。在潍坊市场景下,利用2个模型计算了56种农药在5种作物上共计145种施用方式下的预测环境浓度（PEC）值,利用商值法（RQ）进行风险评估。结果显示有8种农药共13种施用方式在潍坊市场景下存在不可接受的地下水风险。其中,2个模型均显示有不可接受风险的农药是多菌灵和氟磺胺草醚。2个模型PEC值比较结果显示,PRZM-GW的农药风险评估趋势与China-PEARL一致性高,从而验证了China-PEARL的可信性。模型PEC值影响因素分析显示,土壤有机碳分配系数（Koc）对2个模型输出影响最大,可将Koc〉400L·kg^-1作为判断某种农药预测浓度〈0.1μg·L^-1经验性指标。2个模型的PEC值和土壤好氧半衰期的对数呈线性关系,当土壤好氧半衰期〉10d时,模型的PEC值随土壤好氧半衰期的增大而迅速增高。水解半衰期为PRZM-GW模型输入项,决定了PRZM-GW模型模拟的农药浓度随年变化趋势。水中溶解度是China-PEARL的输入项,但对模型PEC值影响很小。

Pesticide Groundwater Risk Assessment with China-PEARL and PRZM-GW Model in Weifang City Scenario

China-PEARL is a pesticide exposure model that has been applied to pesticide groundwater risk assessment in China. Weifang City scenario of PRZM-GW was established based on Weifang City scenario data of China-PEARL. PECs（predicted environmental concentration）of 56 pesticides applied on 5 crops in 145 application methods were calculated by both China-PEARL and PRZM-GW. The risk characterization results with RQ（risk quotient）showed that the groundwater risk of 8 pesticides in 13 application methods was unacceptable.Among them, carbendazim and fomesafen were assessed as unacceptable groundwater risk by both models. The comparison of PECs of the two models indicated that the evaluating results of PRZM-GW and China-PEARL were highly consistent. It verified the credibility of ChinaPEARL. The analysis on the factors affecting the outputs of the two models revealed that Koc had the biggest effect on PECs. Koc〉400 L·kg^-1could be adopted as a preliminary determination index of PEC0.1〈 μg·L^-1. The PECs showed clearly linearly correlation with logged soil aerobic half-life. The PECs of the both models increased steeply when soil aerobic half-life〉10 d. Hydrolysis half-life was used in PRZM-GW and determined the variation trend of pesticide concentration in groundwater. Solubility in water was an input option of China-PEARL which influenced lightly on PECs.