Ni Xiu-Feng, Wang Ru-Wei, Cai Fei-Xuan, Cai Jia-Wei
College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, China.
School of Environment, Jinan University, Guangzhou 511443, China.
Huan Jing Ke Xue. 2021 Apr 8;42(4):1660-1667. doi: 10.13227/j.hjkx.202007298.
Coal-fired power plants (CFPPs) and waste incineration power plants (WIPPs) represent a large portion of polycyclic aromatic hydrocarbons (PAHs) sources in the environment, among which halogenated PAHs (HPAHs) are more toxic to the human body compared with their corresponding parent PAHs. In the current work, we investigated the occurrence, formation mechanism, and toxicity effects of HPAHs in the coal and waste combustion products from three CFPPs and one WIPP. The results indicate that the contents of chlorinated PAHs (Cl-PAHs) in the fly ash from the CFPPs and WIPP were 1.06-1.67 ng·g and 2.76 ng·g, respectively, and the contents of brominated PAHs (Br-PAHs) in the fly ash from the CFPPs and WIPP were 26.4-44.2 ng·g and 6.31 ng·g, respectively. The HPAH contents in the fly ash from the WIPP were significantly higher than those from the CFPPs primarily due to the abundant plastics in the domestic waste, represented by polyvinyl chloride, resulting in the formation of Cl-PAHs during combustion. The HPAH contents in the fly ash from the pulverized coal-fired (PC) boiler were significantly higher than those from the circulating fluidized bed (CFB) boiler mostly due to the higher combustion temperature operated in the PC boiler. The HPAHs in the fly ash from coal combustion were predominantly 7-BrBaA and 9-ClPhe, and those from domestic combustion were predominantly 9-BrPhe and 2-ClAnt. In addition, the contents of 7-BrBaA and 9,10-Br Ant in the coal combustion fly ash were significantly higher than those in domestic waste combustion fly ash, whereas 2-BrFle exhibited a contrasting profile. The content of Br-PAHs in the fly ash treated by semi-dry deacidification was twice that in dust removal fly ash but significantly increased in the chelating agent stabilization fly ash. The Pearson correlation analysis indicated the the formation mechanism of Cl-PAHs and Br-PAHs were the same but a secondary formation of HPAHs during the chelating agent stabilization of the fly ash was deduced. The TEQ values of the HPAHs in the fly ash (8.87×10-15.0×10 ng·g) from the WIPP were similar to those in the fly ash from the CFPPs (10.0×10 ng·g), which were significantly reduced in the fly ash treated by semi-dry deacidification due to the removal of 7-BrBaA. Moreover, the TEQ values of the HPAHs in the fly ash increased 5.4 times after the chelating agent stabilization. The ecological risk should be considered for the CFPP fly ash due to their massive amount of discharge and high TEQ values.
燃煤发电厂（CFPPs）和垃圾焚烧发电厂（WIPPs）是环境中多环芳烃（PAHs）的主要来源，其中卤代多环芳烃（HPAHs）相较于其相应的母体PAHs对人体毒性更大。在当前研究中，我们调查了来自三座CFPPs和一座WIPP的煤炭和垃圾燃烧产物中HPAHs的存在情况、形成机制及毒性效应。结果表明，CFPPs和WIPP飞灰中氯代多环芳烃（Cl-PAHs）的含量分别为1.06 - 1.67 ng·g和2.76 ng·g，CFPPs和WIPP飞灰中溴代多环芳烃（Br-PAHs）的含量分别为26.4 - 44.2 ng·g和6.31 ng·g。WIPP飞灰中的HPAH含量显著高于CFPPs飞灰，主要原因是生活垃圾中以聚氯乙烯为代表的大量塑料，导致燃烧过程中形成Cl-PAHs。煤粉炉（PC）锅炉飞灰中的HPAH含量显著高于循环流化床（CFB）锅炉飞灰，这主要是由于PC锅炉运行温度较高。煤炭燃烧飞灰中的HPAHs主要为7-BrBaA和9-ClPhe，生活垃圾燃烧飞灰中的HPAHs主要为9-BrPhe和2-ClAnt。此外，煤炭燃烧飞灰中7-BrBaA和9,10-Br Ant的含量显著高于生活垃圾燃烧飞灰，而2-BrFle则呈现相反的分布。半干法脱酸处理后的飞灰中Br-PAHs含量是除尘飞灰的两倍，但在螯合剂稳定化飞灰中显著增加。Pearson相关性分析表明，Cl-PAHs和Br-PAHs的形成机制相同，但推测在飞灰螯合剂稳定化过程中存在HPAHs的二次形成。WIPP飞灰中HPAHs的毒性当量（TEQ）值（8.87×10 - 15.0×10 ng·g）与CFPPs飞灰中的（10.0×10 ng·g）相似，半干法脱酸处理后的飞灰中TEQ值因7-BrBaA的去除而显著降低。此外，螯合剂稳定化后飞灰中HPAHs的TEQ值增加了5.4倍。由于CFPP飞灰排放量巨大且TEQ值较高，应考虑其生态风险。
