农田流域是库区周边一个重要的系统，人为活动频繁，导致流域水土流失严重，地表径流携带大量的含汞土壤进入水库，不仅增加了农田流域汞的输出通量，同时也增加了水库汞的污染负荷，但是农田流域内汞的迁移转化特征、输出通量以及对水库汞负荷的贡献还不清楚。因此，本项目拟以重庆市涪陵区王家沟典型农田小流域为研究对象，研究该流域内土壤和水体中汞的分布特征，初步分析人为活动对汞分布的影响，进一步摸清流域内土壤汞的迁移转化特征，估算该流域内汞随地表径流的迁移量，并最终结合研究组已在三峡水库开展的工作，初步估算出三峡库区周边整个农田流域汞的径流流失量，定量评价农田流域对水库汞负荷的贡献，同时，找出影响流域汞迁移的敏感因子，为三峡水库汞面源污染控制提供基础理论。

Agricultural catchment is an important component around reservoir. Frequent human activities in the area always make soil subject to erosion. Thus, surface runoff can carry large amounts of soil with mercury (Hg) into reservoir, resulting in increase of Hg output from agricultural catchment and Hg load in reservoir. However, limited data were published about the Hg transportation in this area, and the runoff output fluxes from such watershed and caused contribution to Hg load in aquatic system were still unclear. Therefore, a typical small agricultural.catchment in Wangjiagou, Chongqing will be chosen to be the study area, aiming to: 1) study the Hg distribution in soil and water in this study area and analyzethe effect of human activities on Hg distribution; 2) clear the characteristics of Hg migration; 3) calculate the Hg outputs from all the agricultural catchments around reservoir based on the previous work in this reservoir. Finally, assess quantificationally the contribution of discharge from agricultural catchment to Hg load of Three George Reservoir. Besides, the sensitivity factors of Hg migration in runoff should be confirmed, which could supply theoretical basis for controlling Hg nonpoint pollution in Three George Reservoir.