Ⅳ级逸度模型在评估温度对污染物环境行为影响中的应用--以松花江硝基苯污染事故为例

Simulated model on the effect of the temperature change on the fate of pollutants:a case study on the Songhua River nitrobenzene pollution accident

通过建立具有温度依附性的Ⅳ级逸度模型,模拟了松花江环境污染事故发生后硝基苯的动态环境行为,重点考察了温度T对其环境行为的影响。模型的主要参数逸度容量和迁移系数与T呈负相关,T对硝基苯在大气中的污染水平影响较大。随着T的降低,污染物从大气向其他环境相富集。0℃条件下,事故发生后水体和大气中硝基苯浓度峰值可分别达到背景值的4.9倍和4.7倍。研究结果表明,Ⅳ级逸度模型能够作为一种比较有效的手段,表征环境温度对突发性环境污染事故发生后污染物环境行为的影响,并对污染物的环境行为进行预测。

A level IV fugacity model is developed to simulate temperature effects on multimedia fate of pollutants emitted from environmental accidents, using nitrobenzene released from the Songhua River pollution accident in late 2005 as a case. The results show that the fugacity capacities in air, water, soil, and sediment and transfer coefficients among different compartments of nitrobenzene increase with the decrease of temperature. Temperature strongly influences nitrobenzene concentration in air. As temperature decreases, pollutants in air phase tend to partition into the other condensed phases. At 0 ℃ , nitrobenzene retained in the atmosphere decreased by 70 % compared with 22.3 ℃ . The peak concentration of nitrobenzene in water and air at 0 ℃ can reach 4.9 and 4.7 times as high as their back-ground concentrations, respectively. At 0 ℃, the peak levels in soil and sediment increased by 0.1% and 1.4% after the pollution accident, respectively. At 0 ℃, nitrobenzene retained in the study area was estimated to be 34 kg. Sediment was the most important sink of nitrobenzene, which retained about 90 % of total dissolved nitrobenzene. Sensitivity analysis shows that advection input concentrations, air-side mass transport coefficients, fraction of solid volume in water, etc., are main factors governing the modeling results. Level IV fugacity model is an efficient method to evaluate the influences of temperature on environmental fate of pollutants released from accidents, and to predict the environmental fate of pollutants.