Tomy G T, Fisk A T, Westmore J B, Muir D C
Freshwater Institute, Department of Fisheries and Oceans, Winnipeg, Canada.
Rev Environ Contam Toxicol. 1998;158:53-128. doi: 10.1007/978-1-4612-1708-4_2.
Polychlorinated-n-alkanes (PCAs) or chlorinated paraffins consist of C10 to C30 n-alkanes with chlorine content from 30% to 70% by mass. PCAs are used as high-temperature lubricants, plasticizers, flame retardants, and additives in adhesives, paints, rubber, and sealants. This review presents the existing data on the environmental chemistry and toxicology of PCAs and a preliminary exposure and risk assessment. There is limited information on the levels, fate, or biological effects of PCAs in the environment. This results both from the difficulty associated with quantifying PCAs, because of the complexity inherent to commercial formulations, and from the limited knowledge of their physicochemical properties and biodegradation rates. There are indications that PCAs are widespread environmental contaminants at ng/L levels in surface waters and ng/g (wet wt) levels in biota. However, environmental measurements of PCAs are very limited in the U.S. and Canada, and are only slightly more detailed in western Europe. Assuming that reported water concentrations are mainly caused by the short chain (C10-C13) compounds, aquatic organisms may be at risk from exposure to PCAs. Fugacity level II modeling for two representative PCAs, using the best available physicochemical property data and estimated degradation rates, suggested that C16C24Cl10 would achieve higher concentrations in biota, sediment, and soil than C12H20Cl6 because of slower degradation rates and lower water solubility. Environmental residence time of C16H24Cl10 is estimated to be 520 d compared to 210 d for C12H20Cl6. Future studies will require better analytical methods and reference materials certified for PCA content. Additional data are needed to evaluate exposure of biota to PCAs in the environment, particularly in light of their continued production and usage around the globe.
多氯正构烷烃（PCA）或氯化石蜡由碳链长度为C10至C30的正构烷烃组成，氯含量按质量计为30%至70%。PCA被用作高温润滑剂、增塑剂、阻燃剂以及粘合剂、涂料、橡胶和密封剂中的添加剂。本综述介绍了关于PCA环境化学和毒理学的现有数据以及初步的暴露和风险评估。关于PCA在环境中的含量水平、归宿或生物学效应的信息有限。这一方面是由于商业配方固有的复杂性导致难以对PCA进行定量，另一方面是由于对其物理化学性质和生物降解速率的了解有限。有迹象表明，PCA是广泛存在的环境污染物，在地表水中的浓度为纳克/升级别，在生物群中的浓度为纳克/克（湿重）级别。然而，在美国和加拿大，对PCA的环境测量非常有限，在西欧也只是稍微详细一些。假设报告的水体浓度主要由短链（C10 - C13）化合物引起，水生生物可能面临接触PCA的风险。使用现有最佳物理化学性质数据和估计的降解速率对两种代表性PCA进行逸度二级建模表明，由于降解速率较慢且水溶性较低，C16C24Cl10在生物群、沉积物和土壤中达到的浓度将高于C12H20Cl6。C16H24Cl10的环境停留时间估计为520天，而C12H20Cl6为210天。未来的研究将需要更好的分析方法和经认证的PCA含量参考物质。需要更多数据来评估生物群在环境中接触PCA的情况，特别是考虑到它们在全球范围内仍在持续生产和使用。
