北京地区二噁英类的环境多介质迁移和归趋模拟

以二噁英类为研究对象,利用LevelⅢ多介质逸度模型模拟计算了稳态假设下二噁英类在北京地区空气相、水相、土壤相和沉积物相中的浓度分布及各相间的迁移通量.结果表明:二噁英类在空气和土壤相中的模拟输出浓度(以I-TEQ计,全文同)范围分别为0.32～0.34 pg/m3和0.33～1.14 ng/kg,而相应环境相中的实测值分别为0.33 pg/m3和1.48 ng/kg,二者吻合较好,验证了该模型在北京地区的适用性;北京地区二噁英类的主要迁移过程为空气相—土相沉降和空气相—水相沉降.土壤和大气降解是二噁英类的主要消亡途径,二者占总降解量的99.1%.土壤相是二噁英类的最大储库,其占总量的97.8%. 

Simulation of the Transfer and Fate of PCDD/Fs in Beijing Using a Steady-State Multimedia Fugacity Model

A multimedia fugacity model(Level Ⅲ) was used to simulate the concentration distribution and transfer fluxes of PCDD/Fs in air,water,soil and sediment in Beijing,China.The results showed that the output concentrations of PCDD/Fs ranged from 0.32 to 0.34 pg/m3 in air and from 0.33 to 1.14 ng/kg in soil.This was in good agreement with the observed concentrations of 0.33 pg/m3 and 1.48 ng/kg in the corresponding environments.The results verified the applicability of this model for the Beijing area.The main transfer processes of PCDD/Fs in Beijing were deposition from air to soil and diffusion from air to water.The degradation of PCDD/Fs in air and soil was found to be the major eliminating pathways for these chemicals,accounting for 99.1% of the total loss.Soil was the largest bulk reservoir of PCDD/Fs,containing 97.8% of total PCDD/Fs in the environment.