Incorporating a weight-of-evidence approach into a tiered assessment for chemicals management, with emphasis on program development and applications in developing countries and emerging economies
Authors: Menzie Charles A. , Guiney Patrick D. , Belanger Scott E. , Lee Kuan-Chun , Arts Gertie , Opeolu Beatrice Olutoyin , Silva de Assis Helena C. 
Published: August 2024

Abstract
A flexible approach is described for incorporating a weight-of-evidence (WoE) methodology into a tiered ecological risk assessment (ERA)/management framework for chemicals. The approach is oriented toward informing decisions about chemicals. Communication is regarded as a critical component of the risk assessment process. The paper resulted from insights gained from seven ERA workshops held by SETAC (Society of Environmental Toxicology and Chemistry, www.setac.org) in the Asia-Pacific, African, and Latin American regions. Formal ERA methods are not fully developed or applied in many of these countries and assessments often begin with tables of risk values and test methods from countries where ERA is already implemented. While appropriate and sometimes necessary, workshop participants had questions about the reliability and relevance of using this information for regionally specific ecosystems with different receptors, fate processes, and exposure characteristics. The idea that an assessment of reliability and relevance of available information and the need for additional information was necessary at an early stage of the assessment process was considered. The judgment of reliability and relevance is central to WoE approaches along with the identification of information needs and the integration of such information. The need to engage in WoE considerations early and throughout the assessment process indicates that a tiered approach is appropriate for unifying the evaluation process in a consistent way from early screening-level steps to later more involved evaluations. The approach outlined in this article is complementary to WoE guidance developed by the Organization for Economic Co-operation and Development and many national guidance documents. To link assessments of risk to management decisions, emphasis is given to communications at each tier between the risk assessor (technical side) and the decision-makers (policy and regulatory side). Tools and information sources are suggested for each tier and suggestions are meant to be illustrative and not prescriptive. Integr Environ Assess Manag 2024;20:2312–2325. © 2024 SETAC
Key Points
Weight of evidence embedded within a tiered assessment and risk management approach provides a structure that can be adopted and modified as needed by developing countries that currently do not have formal or complete assessment systems. Weight of evidence is part of the entire assessment process and is not something that enters into consideration later in the process. Capacity building is needed to share knowledge and to develop in-country capabilities for risk assessment and risk management of chemicals. Organizations like SETAC can play key roles in helping facilitate the sharing of knowledge and the building of capabilities in a manner that involves academia, governments, and business.