地下水砷时空分布对农业灌溉的响应机制及健康风险研究

农业灌溉是影响地下水砷含量的重要因素，但地下水砷对农业灌溉的时空响应需深入研究。本项目研究地下水砷时空分布对农业灌溉的响应机制及健康风险。基于样品测定数据和历史数据，利用地统计学和GIS分析地下水砷时间变化、空间分布变化；分析地下水砷含量和赋存形态、地下水文条件、水文地球化学性质、农业灌溉之间的时空关系；建立地下水砷与农业灌溉因子的时空关系，研究地下水砷对农业灌溉的时空响应机制；建立与验证研究区MODFLOW模型，模拟未来农业灌溉情景下地下水水文时空分布和地下水流场特征；基于MODFLOW模型，识别与验证研究区MT3DMS模型，模拟未来地下水砷的时空再分布；利用“四步法”、地下水砷和皮肤损伤的剂量效应关系评估未来地下水砷暴露的健康风险和皮肤损伤风险。地下水砷对农业灌溉的时空响应机制和时空再分布模拟是本项目的主要创新点。研究结果为研究区饮水安全和制定饮水砷中毒防治方案提供科学依据。

Arsenic concentration in groundwater can be affected by agricultural irrigation. However, the spatial and temporal variations of arsenic in groundwater response to agricultural irrigation should be further investigated. Therefore, the spatial and temporal distribution of arsenic in groundwater response to agricultural irrigation and health risk are observed in Hetao plain, China. The spatial and temporal variations of arsenic in groundwater are analyzed by GIS and Geostatistics based on experimental and literature data. The relationships among total arsenic concentration, arsenic species concentration, groundwater hydrological conditions, groundwater hydrogeochemical properties and agricultural irrigation factor are analyzed. The relationships between groundwater arsenic and agricultural irrigation factors are determined. Then, the response mechanism of groundwater arsenic to agricultural irrigation are investigated. The MODFLOW model in the research area is established and verified. Then, the spatial and temporal distributions of groundwater hydrology and groundwater flow field under future scenarios of agricultural irrigation are simulated by the MODFLOW model. Based on the MODFLOW model, the MT3DMS model in the research area is calibrated and verified. the spatial and temporal redistributions of arsenic in groundwater under future scenarios of agricultural irrigation are simulated by MT3DMS model. Moreover, the spatial and temporal variations of health risk and skin lesion risk are assessed by the USEPA model the dose-response between arsenic and skin lesion. The main innovation of the program is spatial and temporal response mechanism of groundwater arsenic to agricultural irrigation, and the stimulation of the spatial and temporal redistribution of groundwater arsenic. The results can provide scientific basis for drinking water safety and making of the prevention plans for arsenism caused by arsenic in groundwater in the study area.