Environmental risk assessment and testing of UVCBs through balanced consideration of whole substances and representative constituent data: a tripartite perspective

We’re pleased to share a new publication from the HESI Global UVCB Committee: “Environmental risk assessment and testing of UVCBs through balanced consideration of whole substances and representative constituent data: a tripartite perspective.”

The issue: Substances of unknown or variable composition, complex reaction products, or biological materials (UVCBs) are common in commerce and make up an estimated 20–25% of substances in global chemical registries. Their variable and sometimes partially uncharacterized compositions can make environmental testing and risk assessment challenging.

Why it matters: Regulators, industry, and the scientific community need practical, science-based and fit-for-purpose approaches to test and risk assess complex substances in order to protect ecological and human health.

The problem: Traditional methods are often ill-adapted to the testing of complex substances, but the testing of their constituents can sometimes fail to represent realistic environmental conditions. Therefore, solely evaluating the whole substance (WS) or its representative constituents (RCs) would only provide limited information.

The solution: Drawing on insights from HESI Global’s international, tripartite workshop (Reykjavik, Iceland; Sept 18–19, 2023), this paper refines an exposure-centric tiered framework and proposes a guide to help UVCB evaluators develop testing and assessment strategies that balance WS and RC data.

The benefit: A more systematic, transparent, efficient, and robust weight-of-evidence approach for UVCB testing and environmental risk assessment.

Read the full article here: Deglin et al., 2026. Environmental risk assessment and testing of UVCBs through balanced consideration of whole substances and representative constituent data: a tripartite perspective. Integrated Environmental Assessment and Management. https://doi.org/10.1093/inteam/vjaf200