Abstract:

Waste incineration has become one of the important emission sources of polybrominated diphenyl ethers (PBDEs). It is of great significance to study the emission and pollution characteristics of PBDEs in waste incineration plants for understanding their environmental behavior and identifying their environmental risks. Three waste incineration plants were selected to analyze the PBDEs in their flue gas and surrounding soil. The results showed that the mass concentration of PBDEs in the flue gas of waste incineration plants was between 1 and 500 pg∙m^-3, and the difference in the concentration of PBDEs in the flue gas of waste incineration plants may be primarily related to the incineration process. Low-brominated PBDEs dominated PBDEs in flue gas, mainly derived from the incomplete debromination of high-brominated PBDEs or the regeneration of low-brominated substances during the pyrolysis process. The concentrations of monomers such as BDE-1, BDE-3, BDE-47 and BDE-209 were relatively high. The mass fraction of PBDEs in the soil around the waste incineration plants ranged from 10 to 150 ng∙g^-1 and the pollution level was medium. BDE-209, BDE-47, BDE-77, BDE-118 and other monomers had higher concentrations. According to the ranking of PBDEs concentration in the flue gas and surrounding soil of the waste incineration plants, and the Pearson correlation analysis and principal component analysis (PCA) results, the emission of PBDEs from the waste incineration plants were still affected by commercial pentabromo, octabromo and decabromodiphenyl ether industrial products, and PBDEs in soil may be mainly originated from atmospheric deposition. Additionally, the composition of PBDEs monomers and congeners in the surrounding soil showed a decrease in the proportion of low-brominated PBDEs and an increase in the proportion of high-brominated PBDEs. It was essentially due to the low vapor pressure of the congeners of high-brominated PBDEs, enriching them in the particulate phase and subsequently accelerating the accumulation in the soil due to the particulate dry and wet deposition. The congeners of low-brominated PBDEs, however, have higher vapor pressures, making them easier to concentrate in the gas phase and more easily to volatilize from the soil.

Key words: polybrominated diphenyl ethers, waste incineration plants, flue gas, soil, pollution characteristics

摘要：

垃圾焚烧已成为多溴联苯醚（PBDEs）的重要排放源之一,研究垃圾焚烧厂PBDEs的排放和污染特征对于掌握它们的环境行为和识别其环境风险有极为重要的意义。以3个垃圾焚烧厂为研究对象,对其排放的烟气及周边土壤中的PBDEs进行分析,结果表明,垃圾焚烧厂烟气中PBDEs质量浓度在1—500 pg∙m^-3之间,不同垃圾焚烧厂烟气中PBDEs的含量差异可能主要与焚烧工艺有关。烟气中PBDEs含量占主导地位的为低溴代PBDEs,其主要来源于热解过程中高溴PBDEs的不完全脱溴或低溴物质的重新生成,BDE-1、BDE-3、BDE-47和BDE-209等单体含量较高。垃圾焚烧厂周边土壤PBDEs质量分数在10—150 ng∙g^-1之间,污染水平属中等,同类物中低溴代PBDEs占比45%—65%,BDE-209占比25%—43%,BDE-209、BDE-47、BDE-77、BDE-118等单体含量较高。垃圾焚烧厂烟气及周边土壤PBDEs含量排序、Pearson相关性分析和主成分分析说明垃圾焚烧厂PBDEs排放仍受商业五溴、八溴和十溴联苯醚工业品影响,土壤中PBDEs可能主要来源于大气的沉降作用。同时,垃圾焚烧厂周边土壤中PBDEs单体和同类物组成均表现出低溴代PBDEs占比下降、高溴代PBDEs占比上升的特征,这主要是由于高溴代PBDEs同类物具有较低的蒸汽压,其更容易富集在颗粒相上,颗粒物易于在垃圾焚烧厂周边干湿沉降,而低溴代PBDEs同类物具有较高的蒸汽压,使其更容易富集于气相逸散,也更容易从土壤中挥发。

关键词: 多溴联苯醚, 垃圾焚烧厂, 烟气, 土壤, 污染特征