市售聚氯乙烯(PVC)塑料制品中短链及中链氯化石蜡含量分析及排放预测

Determination and emission estimation of short-chain and medium-chain chlorinated paraffins in PVC plastic products

氯化石蜡(chlorinated paraffins,CPs)是一系列正构烷烃氯代混合物,常用作阻燃和塑化添加剂.其中,短链氯化石蜡(SCCPs)和中链氯化石蜡(MCCPs)具备典型持久性有机污染物属性.作为聚氯乙烯(PVC)最大的生产和消费国,我国约有70%CPs产品被添加到PVC塑料当中,其添加SCCPs和MCCPs的含量水平和潜在排放暴露风险需要重点关注.本研究采用气相色谱-静电场轨道阱高分辨质谱(GC-Orbitrap-HRMS)检测市售5类25种典型PVC塑料中SCCPs和MCCPs水平.结果表明,塑料中SCCPs和MCCPs的浓度范围为0.010—64.2 mg·g^(−1)和0.002—50.9 mg·g^(−1),不同样品间的SCCPs和MCCPs的含量差异明显,浓度水平依次为线缆>地毯/垫>地板革>硬管>布线槽.不同材料中SCCPs同系物分布存在差异,线缆护套和地毯/垫中C_(13)-CPs为SCCPs的主要同族体,地板革中SCCPs以C_(10)-CPs为主,硬管和布线槽中各碳同族体相对丰度无显著差异.MCCPs在所有材料中分布模式相似,均以C_(14)-CPs为主.SCCPs以Cl_(7)和Cl_(8)为主,MCCPs的氯分布更为集中,以Cl_(8)为主.通过排放预测模型评估了5类PVC塑料中SCCPs和MCCPs向空气、地表水和土壤中的年最大排放量,分别为2.73 kt(空气)、0.82 kt(地表水)以及0.11 kt(土壤),确定PVC塑料的生产及使用是环境中SCCPs和MCCPs的重要排放源.

Chlorinated paraffins(CPs)are a series of synthetic chlorinated n-alkanes,which are widely used as flame retardants and plasticizers.Among them,short-chain chlorinated paraffins(SCCPs)and medium-chain chlorinated paraffins(MCCPs)attract worldwide attentions due to their persistence,long range transportation,bioaccumulation and toxicity,which have been included as persistent organic pollutants(POPs)and candidate POPs,respectively.China is the largest producer and consumer of polyvinyl chloride(PVC)products,in which approximately 70%of CP products have been applied.Therefore,the concentrations of SCCPs and MCCPs in commercial PVC products and their potential exposure risk should be a critical concern.In this study,chromatography-orbitrap-high-resolution mass spectrometry(GC-Orbitrap-HRMS)was adopted to determine the concentrations and congener pattern characteristics of SCCPs and MCCPs in 25 species in five PVC product categories.Their concentrations were in the range of 0.010—64.2 mg·g^(-1) for SCCPs and 0.002—50.9 mg·g^(-1) for MCCPs,respectively.It differed a lot among the individual samples,following cable>PVC mat>PVC flooring>pipe>groove.The C_(13)-CPs predominated in SCCP congener patterns in carpets/mats and cables,while the C_(10)-CPs exhibited the highest relative abundance in flooring.No significant differences of SCCP congener patterns were found in the pipe and groove.The congener patterns of MCCPs were similar in all the test products,with the C_(14)-CPs in majority.From the perspective of chlorine distribution characteristics,the abundances of Cl_(7) and Cl_(8) congeners of SCCPs were dominated while MCCPs was predominated by Cl_(8) congeners.The annual emissions of SCCPs and MCCPs from these five PVC product categories were evaluated by the emission prediction mode,the maximum emissions of which were 2.73 kt(air),0.82 kt(surface water)and 0.11 kt(soil),respectively.The production and use of PVC products was indicated as a potential source of SCCPs and MCCPs released to the environment.