205740Stantec (ChemRisk), Boston, MA, USA.
205740Stantec (ChemRisk), Aliso Viejo, CA, USA.
Toxicol Ind Health. 2023 Jan;39(1):49-65. doi: 10.1177/07482337221140946. Epub 2022 Nov 24.
The United States Environmental Protection Agency (EPA) regulates chemical manufacture, import, processing, distribution, use, and disposal under the 2016 amended Toxic Substances Control Act (TSCA) for the purposes of protecting the public and sensitive populations-including workers-from chemical exposure risk. The publication of several TSCA risk evaluations provided a unique opportunity to evaluate the evolving regulatory approach for assessing the dermal exposure pathway in occupational settings. In this analysis, the occupational dermal exposure assessment methods employed in several TSCA risk evaluations were assessed. Specifically, a methodology review was conducted for the occupational dermal scenarios of manufacturing and feedstock use in the risk evaluations of three chlorinated organic chemicals: trichloroethylene, carbon tetrachloride, and perchloroethylene. Additionally, alternative exposure estimates were generated using the exposure model IH SkinPerm. The review and alternative exposure analyses indicate that the current TSCA modeling approach may generate total dermal absorbed doses for chlorinated chemical manufacturing and feedstock use scenarios that are 2- to 20-fold higher than those generated by IH SkinPerm. Best-practice recommendations developed in the methodology review support a tiered, integrated approach to dermal exposure assessment that emphasizes collecting qualitative data; employing validated, peer-reviewed models that align with current industrial practices; and gathering empirical sampling data where needed. Collaboration among industry, EPA, and other stakeholders to share information and develop a standard approach to exposure assessment under TSCA would improve the methodological rigor of, and increase confidence in, the risk evaluation results.
美国环境保护署 (EPA) 根据 2016 年修订的《有毒物质控制法》(TSCA) 对化学品的制造、进口、加工、分销、使用和处置进行监管,目的是保护公众和敏感人群(包括工人)免受化学暴露风险。几项 TSCA 风险评估的公布为评估职业环境中皮肤暴露途径的不断发展的监管方法提供了独特的机会。在这项分析中,评估了几项 TSCA 风险评估中使用的职业皮肤暴露评估方法。具体来说,对三种氯化有机化学品(三氯乙烯、四氯化碳和全氯乙烯)的风险评估中的制造和原料使用的职业皮肤场景进行了方法学审查。此外,还使用暴露模型 IH SkinPerm 生成了替代暴露估计值。审查和替代暴露分析表明,当前的 TSCA 建模方法可能会为氯化化学品制造和原料使用场景生成的总皮肤吸收剂量比 IH SkinPerm 生成的剂量高 2 到 20 倍。方法学审查中制定的最佳实践建议支持一种分层、综合的皮肤暴露评估方法,该方法强调收集定性数据;使用经过验证、同行评审的模型,这些模型与当前的工业实践保持一致;并在需要时收集经验采样数据。行业、EPA 和其他利益相关者之间的合作,以分享信息并制定 TSCA 下暴露评估的标准方法,将提高风险评估结果的方法严谨性并增强对其的信心。