Applying the "Weight of Evidence" Approach to Developing Countries

Weight of evidence (WoE) is a methodology used for chemical risk assessment that combines relevance, quality, reliability, and consistency of data to strengthen a body of evidence. Can WoE approaches be used to evaluate chemicals with few data and inform decision‐making even when information is limited?

In "Advancing the Weight of Evidence Approach to Enable Chemical Environmental Risk Assessment for Decision-Making and Achieving Protection Goals," Exponent Principal Scientist Charles Menzie, Ph.D., in collaboration with co-authors from industry and academia, reviews four articles that examine how WoE approaches can enhance chemical risk screening and management, especially in developing countries.

As part of a special series titled "Practical Considerations for Application of Weight of Evidence in Chemical Evaluations" in Integrated Environmental Assessment and Management, the articles are based on Society of Environmental Toxicology and Chemistry (SETAC) workshops held between 2015 and 2019 in North America, Europe, Asia, Latin America, and Africa on WoE approaches in chemical risk assessment. Key takeaways included:

• The importance of including WoE at the earliest stages of an assessment process to ensure data reliability and relevant testing procedures
• The significance of communication between risk assessors and risk managers

The authors caution that while WoE approaches can be used to analyze both data rich and data poor chemicals, the "WoE approach does not increase or decrease the risk of the chemical but rather improves the quality of an assessment by reducing uncertainty surrounding the likelihood that existing conditions can or cannot cause an adverse effect or that a hypothetical future action (or condition) will cause an adverse effect."

Together, the articles show the value of applying WoE for effective chemical risk assessment and science‐based policy implementation.

From the publication: "The workshops held by SETAC on WoE revealed that developing countries were particularly interested in the reliability of toxicity, exposure, and derived benchmark values published by other countries for screening or regulating chemicals."