台州水系表层沉积物典型POPs污染现状及生态风险

为探讨典型废物拆解地工业结构转型期环境POPs(persistent organic pollutants,持久性有机污染物)污染特征变化情况,使用气相色谱/高分辨质谱法测定了台州水系表层沉积物中PCDD/Fs(二英类)、dl-PCBs(共平面多氯联苯)和PBDEs(多溴联苯醚),并利用主因子分析等手段分析了其来源. 结果表明,台州椒江和金清闸海湾2387-PCDD/Fs毒性当量浓度(以WHO₂₀₀₅-TEQ计,下同)中位值分别为3.18和1.91 ng/kg,dl-PCBs毒性当量浓度分别为0.26和0.62 ng/kg,w(∑PBDEs)分别为22.5和19.7 μg/kg,处于我国和全球河流(海湾)表层沉积物POPs污染的中等水平,低于其他电子废物拆解地等严重污染区. 台州河流(海湾)表层沉积物PCDD/Fs主要来源于燃煤,dl-PCBs主要来源于历史上多氯联苯的使用或电子废物拆解活动,PBDEs主要来源于相关阻燃剂的使用和电子废物拆解活动. 位于化工园区排水口的YTZ采样点PCDD/Fs和dl-PCBs的毒性当量浓度分别达到6.54×104和7.84×103 ng/kg,污染可能来源于化工废料加工和再生金属生产,表明台州在工业结构转型期出现的新POPs污染源,应引起重视. 台州部分表层沉积物样品中的PCDD/Fs和dl-PCBs的总毒性当量浓度超过美国和加拿大的沉积物质量指导值,存在一定的生态风险. 

Occurrence and Ecological Risks of Typical POPs in Surface Sediments from the Taizhou River System

In order to investigate the possible changes of enviromental persistent organic pollutant (POPs) pollution properties during the industrial restructuring in typical e-waste dismantling areas, dioxins (PCDD/Fs), co-planar polychlorinated biphenyls (dl-PCBs) and polybrominated diphenyl ethers (PBDEs) in surface sediments from streams in Taizhou were sampled and analyzed with gas chromatography/high resolution mass spectrometry (GC/HRMS). In addition, the possible sources were also investigated by principal component analysis (PCA). The mean concentrations in Jiaojiang River and Jinqingzha Harbor were 3.18 and 1.91 ng/kg(WHO₂₀₀₅-TEQ) for 2378-PCDD/Fs, 0.26 and 0.62 ng/kg(WHO₂₀₀₅-TEQ) for dl-PCBs, 22.5 and 19.7 μg/kg for PBDEs, which were at the medium level of POPs in surface sediments in China and the world, and much lower than those in heavily polluted places as other e-waste dismantling sites. The results show that PCDD/Fs in surface sediment in Taizhou mainly originate from coal burning. dl-PCBs can be attributed to the residue of technical PCB products in the history or e-waste dismantling activities. PBDEs sources include the use of technical PBDEs products and the e-waste dismantling activities. YTZ site is close to a discharge port of a chemical engineering industrial zone; its PCDD/Fs and dl-PCBs concentrations were as high as 6.54×104 and 7.84×103 ng/kg, respectively. The possible sources are the secondary metallurgy or chemical waste recycling. This implies that new POPs emission sources may appear, and much more attention should be paid during industrial restructuring in the e-waste dismantling area. Some surface sediments have total toxic equivalent quantities exceeding the interim sediment quality guidelines (ISQGs) suggested by Canadian Environmental Council and United States Environmental Protection Agency, indicating ecological risks in Taizhou.