Hydrus-1D软件在地下水污染风险评价中的应用

Application of Hydrus-1D software in groundwater contamination risk assessment

以北京市东南郊再生水灌区为研究区域,应用Hydrus-1D软件构建水流、溶质运移模型,模拟再生水连续灌溉入渗过程中水流在包气带中的运动,并以再生水中的典型有机污染物多环芳烃萘、菲为研究对象,模拟其随灌溉水在包气带中的迁移衰减反应过程,结合MapGIS6.7,将Hydrus-1D的点模拟结果应用于大面积、区域性的污染评价,通过与研究区地下水萘、菲的背景值进行对比,分级评估地下水污染风险.结果表明,经过50年连续灌溉后,再生水灌区整体地下水萘、菲污染风险较低,萘的污染风险高于菲,灌区内高污染风险区域主要位于凤港减河、红旗干渠与凤官沟交汇处以及东风干渠、永乐河与通大边沟之间.

To investigate the groundwater contamination risk assessment method, the reclaimed water irrigation farmland lies in the southeast suburb of Beijing was chosen as study area, and Hydrus-1D software was selected to delineate water flow and solute transport process of the water infiltration vertically in vadose zone while reclaimed water irrigation. Naphthalene and phenanthrene, the typical organic pollutants in reclaimed water were chosen as the target contaminants. The transportation and degradation process of them were simulated under the continuous infiltration pattern. After the simulation, 226 points simulated results of Hydrus-lD were applied to the whole study area to assess groundwater contamination risk, and used MapGIS 6.7 to get the risk map. Through comparing the results to the background value of naphthalene and phenanthrene in the groundwater of study area, the groundwater contamination risk were discussed. The results suggested that the risk of naphthalene and phenanthrene in groundwater of the whole study area was very low even after 50 year＇s reclaimed water irrigation. The pollution risk of naphthalene to groundwater was higher than phenanthrene. The highest pollution risk regions in the study area were mainly located in Fenggang distributaries, the intersection of Hongqi main channel and Fengguan channel, and the region between Yongle river and Tongda intercepting ditch.