Giesy J P, Kannan K
Department of Zoology, National Food Safety and Toxicology Center, Michigan State University, East Lansing 48824, USA.
Crit Rev Toxicol. 1998 Nov;28(6):511-69. doi: 10.1080/10408449891344263.
Polychlorinated biphenyls (PCBs) are persistent, bioaccumulative, and toxic contaminants in the environment. Individual PCB congeners exhibit different physicochemical properties and biological activities that result in different environmental distributions and toxicity profiles. The variable composition of PCB residues in environmental matrices and their different mechanisms of toxicity complicate the development of scientifically based regulations for the risk assessment. In this article various approaches for the assessment of risks of PCBs have been critically examined. Recent developments in the toxic equivalency factor (TEF) approach for the assessment of toxic effects due to dioxin-like PCBs have been examined. PCB exposure studies that describe non-dioxin-like toxic effects, particularly neurobehavioral effects and their effective doses in animals were compiled. A comparative assessment of effective doses for dioxin-like and non-dioxin-like effects by PCBs has been made to evaluate the relative significance of non-ortho-and ortho-substituted PCBs in risk assessment. Using mink as an example, relative merits and implications of using TEF and total PCB approaches for assessing the potential for toxic effects in wildlife was examined. There are several advantages and limitations associated with each method used for PCB risk assessment. Toxic effects due to coplanar PCBs occur at relatively smaller concentrations than those due to non-dioxin-like PCBs and therefore the TEF approach derives the risk assessment of PCBs, in the environment. The need for the refinement of TEF approach for more accurate assessment of risks is discussed.
多氯联苯（PCBs）是环境中持久性、生物累积性和有毒的污染物。单个多氯联苯同系物具有不同的物理化学性质和生物活性，导致不同的环境分布和毒性特征。环境基质中多氯联苯残留物的组成各异及其不同的毒性机制，使得制定基于科学的风险评估法规变得复杂。本文对评估多氯联苯风险的各种方法进行了批判性审视。研究了用于评估类二噁英多氯联苯毒性效应的毒性当量因子（TEF）方法的最新进展。整理了描述非类二噁英多氯联苯毒性效应，特别是神经行为效应及其在动物体内有效剂量的多氯联苯暴露研究。对多氯联苯类二噁英效应和非类二噁英效应的有效剂量进行了比较评估，以评估非邻位和邻位取代多氯联苯在风险评估中的相对重要性。以水貂为例，研究了使用TEF和总多氯联苯方法评估野生动物中毒性效应可能性的相对优缺点。用于多氯联苯风险评估的每种方法都有若干优点和局限性。与非类二噁英多氯联苯相比，共面多氯联苯产生毒性效应的浓度相对较小，因此TEF方法得出了环境中多氯联苯的风险评估结果。讨论了改进TEF方法以更准确评估风险的必要性。
