上海城区多环芳烃的多介质归趋模拟研究

Simulation of multimedia fate of PAHs in Shanghai City

利用城市多介质逸度模型模拟了稳态假设下上海城区16种PAHs在大气、水体、沉积物和植物等中的浓度分布,与实测值进行对比,并根据模拟结果计算了相间迁移通量.结果表明,大气直接排放输入是PAHs进入环境的主要途径,迁移过程包括扩散、沉降和侵蚀等,平流输出是其在系统中损失的主要途径;土壤和沉积物是PAHs主要的汇(占94.4%),其在不透水层上覆盖的膜中浓度达到最大(156g/m3),PAHs在沉积物和土壤中停留时间最长;随着环数的增加,PAHs在水体、植被和土壤中的降解损失所占比例从2.3%逐渐增加至48.9%,而在大气中的降解损失则从91.5%减少至4.0%.模型计算浓度与实测浓度吻合较好,验证了模型的可靠性,并通过灵敏度分析,确定了模型的关键参数.

The MUM model was used to simulate the concentration distribution of PAHs in air,water,sediment,soil and plants in Shanghai city.Atmospheric emission was the dominant PAHs.The transport processes included diffusion,sedimentation,erosion ect.;while advective transport caused the main loss in the system.Sediment/soil was the main sink of PAHs（up to 94.4% of total mass）,and the highest PAHs concentration was calculated in the film above aquifuge.The retention time of PAHs was highest in sediment/soil,and with the increasing rings,the reaction loss proportion of PAHs in water,plant and soil was increasing,while it was decreasing in air.The reliability of the model was verified by the agreement between the calculated and measured the concentrations.The key model parameters were selected by means of sensitivity analysis.