生活垃圾焚烧厂周边环境空气中PCDD/Fs含量及分布特征

对我国某工业区生活垃圾焚烧厂周边5km范围内14个采样点环境空气中四氯~八氯代二 英(2,3,7,8-PCDD/Fs)含量及其组成特征进行了分析.结果表明该垃圾焚烧厂周边环境空气PCDD/Fs浓度的变化范围为1.74~15.2pg/m3(0.156~1.44pg I-TEQ/m3),均值为4.60pg/m3(0.426pg I-TEQ/m3),其中3个点位接近或超出日本环境空气质量标准限值(0.6pg I-TEQ/m3),表明某些区域处于一个较高的污染水平;最大浓度点位于焚烧设施下风方向1.3km处,与AERMOD预测的最大落地浓度位置一致.1,2,3,4,6,7,8-HpCDF和OCDD是空气中二 英质量浓度主要贡献因子,而2,3,4,7,8-PeCDF是毒性当量浓度的主要贡献因子.样品中二 英同族物分布的指纹特征显示出可能受MSWI源影响点位与非MSWI影响(或受此源影响较小)点位的区别.主成分分析(PCA)源解析结论与空间分布以及指纹特征分析结论基本一致,且更具体地判断MSWI的影响点位,在一定程度上说明了此方法的可靠性.二 英呼吸暴露剂量估算结果表明该区域人群二 英呼吸暴露风险总体处于较为安全的水平.

Concentrations and profiles of PCDD/Fs in ambient air around a municipal solid waste incinerator

The concentrations and profiles of PCDD/Fs in ambient air around a municipal solid waste incinerator (MSWI) in an industrial area were obtained. The concentrations of 2,3,7,8-PCDD/Fs of the 14 ambient air sampling sites were in the range of 1.74~15.2 pg/m3 (0.156~1.44pg I-TEQ/m3), with an average value of 4.60 pg/m3(0.426pg I-TEQ/m3), and the levels of 3 sampling sites were higher than the ambient air standard of 0.6 pg TEQ m-3 for dioxins proposed by Japan, which demonstrated that the PCDD/Fs concentrations around the MSWI in some area in this study were a bit high. And the highest concentration of 2,3,7,8-PCDD/Fs was found at a downwind location, 1.3km away from the MSWI, which was consisted with the result of the maximum ground concentration calculated by AERMOD models. 1,2,3,4,6,7,8-HpCDF and OCDD were the dominated PCDD/Fs in all the samples, while 2,3,4,7,8-PeCDF was the dominated congener contributed to the total toxicity equivalent (TEQ). The homologue profiles of PCDD/Fs in some ambient air locations were similar to those in the flue gas of the MSWI, indicating the possibility of influence by the source, while the profiles of other sites differed with them with a significantly higher TCDD contribution. Principal component analysis (PCA) results revealed that the concentrations of PCDD/Fs in ambient air in some areas were obviously affected by the MSWI, which was coincided with the fingerprint analysis. Dioxin inhalation exposure dose estimation results showed that the dioxin inhalation exposure risk of the population living in the study areas was still at a relative safe level.