Substances of unknown or variable composition, complex reaction products, or biological materials (UVCBs) pose unique risk assessment challenges to regulators and to product registrants. These substances can contain many constituents, sometimes partially unknown and/or variable, depending on fluctuations in their source material and/or manufacturing process. International regulatory agencies have highlighted the difficulties in characterizing UVCBs and assessing their toxicity and environmental fate. Several industrial sectors have attempted to address these issues by developing frameworks and characterization methods. Based on the output of a 2016 workshop, this critical review examines current practices for UVCB risk assessment and reveals a need for a multipronged and transparent approach integrating whole‐substance and constituent‐based information. In silico tools or empirical measurements can provide information on discrete and/or blocks of UVCB constituents with similar hazard properties. Read‐across and/or whole‐substance toxicity and fate testing using adapted emerging methods can provide whole‐substance information. Continued collaboration of stakeholders representing government, industry, and academia will facilitate the development of practical testing strategies and guidelines for addressing regulatory requirements for UVCBs. Environ Toxicol Chem 2020;39:2097–2108. © 2020 Health and Environmental Sciences Institute. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

中文翻译：

---

改善未知或可变成分的物质，复杂反应产物或生物材料的环境风险评估。

未知或可变成分的物质，复杂的反应产物或生物材料（UVCB）对监管者和产品注册人构成独特的风险评估挑战。这些物质可能包含许多成分，有时是部分未知和/或可变的，具体取决于其原料和/或制造工艺的波动。国际监管机构已经强调了表征UVCB以及评估其毒性和环境命运方面的困难。一些工业部门已尝试通过开发框架和表征方法来解决这些问题。根据2016年研讨会的结果，这项重要的审查检查了UVCB风险评估的当前实践，并揭示了需要一种多管齐下和透明的方法来整合基于整体物质和基于成分的信息。在计算机工具或经验测量中，可以提供有关具有类似危险特性的UVCB成分的离散和/或块的信息。使用适应性新兴方法进行的交叉阅读和/或全物质毒性和命运测试可提供全物质信息。代表政府，行业和学术界的利益相关者的持续合作将促进制定实用的测试策略和准则，以解决UVCB的法规要求。使用适应性新兴方法进行的交叉阅读和/或全物质毒性和命运测试可提供全物质信息。代表政府，行业和学术界的利益相关者的持续合作将促进制定实用的测试策略和准则，以解决UVCB的法规要求。使用适应性新兴方法进行的交叉阅读和/或全物质毒性和命运测试可提供全物质信息。代表政府，行业和学术界的利益相关者的持续合作将促进制定实用的测试策略和准则，以解决UVCB的法规要求。2020年《环境毒理学》； 39：2097–2108。©2020健康与环境科学研究所。Wiley Periodicals LLC代表SETAC发布的《环境毒理学和化学》。