废弃电容器封存点及旧工业场地多氯联苯的污染特征

Characteristics of PCBs in a Capacitor Storage Site and an Industrial Brownfield

研究了四川资阳机车厂废弃电力电容器封存点与旧工业场地土壤与降尘中28种多氯联苯(PCBs)的污染水平与组成特征.电容器封存山洞未封闭洞口处土壤中PCBs含量最高,28种PCBs的总含量(ΣPCBs)达227 502 ng.g-1,铸铁车间窗台降尘中也有高残留的PCBs,ΣPCBs在10μg.g-1以上,封存点和铸铁车间样品中PCBs单体含量之间均存在显著的正相关关系(P<0.01).高污染样品中PCBs的同族体分布均以四氯代PCBs为最高,其次为三氯代PCBs和五氯代PCBs.与封存点土壤相比,铸铁车间样品中高氯代PCBs的贡献更大.12种类二英PCBs的毒性当量(TEQ)介于75.43～24 027 pg.g-1之间,远大于电子垃圾拆解区土壤,但普遍都以PCB126的毒性当量贡献占绝对优势.

The levels and congener patterns of 28 PCBs compounds were investigated in soil and dust fallout collected in a capacitor storage site and an industrial brownfield,respectively in Sichuan Ziyang Locomotive Factory.The highest concentration of the total PCBs（PCBs=227 502 ng·g-1） was found in soil collected from the front gate（unsealed） of the capacitor storage tunnel.Very high levels of PCBs,exceed 10 μg·g-1,were also found in the dust collected from the window sill of an iron foundry.There were significant positive correlations（P0.01） among PCB congener concentration in the storage site and the iron foundry samples.The major contribution to the total content of PCBs in the high contaminated samples was tetrachlorinated biphenyls,followed by tri-and penta-chlorinated biphenyls.Hexa-and higher chlorinated biphenyls contributed more to PCBs in the iron foundry than those in the storage site.The total toxicity equivalents（TEQ） of 12 dioxin-like congeners varied in the range of 75.43-24 027 pg·g-1 and were much higher than those in soils of e-waste recycling sites.However,PCB126 contribute the most to the TEQ in most cases.