Risk Assessment in the 21st Century (RISK21) Committee
Risk Assessment in the 21st Century (RISK21) Committee
The mission of the RISK21 Project is to harmonize the approach to how the world evaluates chemicals using a risk-based approach. The RISK21 webtool application supports a problem formulation-based, exposure-driven, tiered acquisition approach that leads to an informed decision.
Version 2.0 of the RISK21 webtool is now available. To access the RISK21 Webtool, please visit www.risk21.org.
Principles of RISK21
- Problem-formulation based
- Risk-based at each step of the process
- Use of prior knowledge
- Fit for purpose
- Value of information
- “Enough precision to make the decision”
- Provide a framework that is flexible, transparent, visual
- Developed a risk assessment approach that embraces advance in scientific knowledge and methods
- Actively involved over 120 participants (government, industry, academia, NGOs) through 6 years of work
- Published 8 manuscripts in Critical Reviews in Toxicology
- Reached over 500 participants in 5 countries on three continents via 7 hands-on case-study workshops
- Revised current thinking about how to approach the science and art of risk assessment
21st Century Framework
- Roadmap and Matrix: The RISK21 webtool application allows users to input estimated exposure and toxicity data for each chemical, and will plot the intersection area, overlaying a risk matrix represented as a heat map.
- Create Custom Plots: Users can interact with the RISK21 webtool application to visualize their own risk data, creating a custom plot which will be displayed on the screen.
- Transparent and Consistent: The webtool approach allows users to optimize the use of resources and information available for chemical risk assessment.
- Continued outreach and communication
- Additional illustration and application via case studies
- Ongoing dialog on advances and needs
Case study workshop with Chinese Food Safety Authority; follow-up to previous course held in 2015; engaged regulators from every province in China.
Presentation on “Using Exposure Bands for Rapid Decision-Making in the RISK21 Tiered Exposure Assessment” at the ICCA-LRI and JRC Workshop on “Fit-For-Purpose Exposure Assessments For Risk-Based Decision Making” by Rosemary Zaleski (ExxonMobil).
Continuing education course at IUTOX / CTDC.
Presentation on RISK21 at the “Progress and Challenges Implementing 21st Century Safety Evaluations: Environmental Health ICG Meeting” by Michelle Embry (HESI).
The Health and Environmental Sciences Institute (HESI) Risk Assessment in the Twenty-first Century (RISK21) project was initiated to address and catalyze improvements in human health risk assessment. RISK21 is a problem formulation-based conceptual roadmap and risk matrix visualization tool, facilitating transparent evaluation of both hazard and exposure components. The RISK21 roadmap is exposure-driven, that is, exposure is used as the second step (after problem formulation) to define and focus the assessment. This paper describes the exposure tiers of the RISK21 matrix and the approaches to adapt readily available information to more quickly inform exposure at a screening level. In particular, exposure look-up tables were developed from available exposure tools (European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) Targeted Risk Assessment (TRA) for worker exposure, ECETOC TRA, European Solvents Industry Group (ESIG) Generic Exposure Scenario (GES) Risk and Exposure Tool (EGRET) for consumer exposure, and USEtox® for indirect exposure to humans via the environment) and were tested in a hypothetical mosquito bed netting case study. A detailed WHO risk assessment for a similar mosquito net use served as a benchmark for the performance of the RISK21 approach. The case study demonstrated that the screening methodologies provided suitable conservative exposure estimates for risk assessment. The results of this effort showed that the RISK21 approach is useful for defining future assessment efforts, focusing assessment activities and visualizing results.
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The Health and Environmental Sciences Institute (HESI) has developed a framework to support a transition in the way in which information for chemical risk assessment is obtained and used (RISK21). The approach is based on detailed problem formulation, where exposure drives the data acquisition process in order to enable informed decision-making on human health safety as soon as sufficient evidence is available. Information is evaluated in a transparent and consistent way with the aim of optimizing available resources. In the context of risk assessment, cumulative risk assessment (CRA) poses additional problems and questions that can be addressed using the RISK21 approach. The focus in CRA to date has generally been on chemicals that have common mechanisms of action. Recently, concern has also been expressed about chemicals acting on multiple pathways that lead to a common health outcome, and non-chemical other conditions (non-chemical stressors) that can lead to or modify a common outcome. Acknowledging that CRAs, as described above, are more conceptually, methodologically and computationally complex than traditional single-stressor risk assessments, RISK21 further developed the framework for implementation of workable processes and procedures for conducting assessments of combined effects from exposure to multiple chemicals and non-chemical stressors. As part of the problem formulation process, this evidence-based framework allows the identification of the circumstances in which it is appropriate to conduct a CRA for a group of compounds. A tiered approach is then proposed, where additional chemical stressors and/or non-chemical modulating factors (ModFs) are considered sequentially. Criteria are provided to facilitate the decision on whether or not to include ModFs in the formal quantitative assessment, with the intention to help focus the use of available resources to have the greatest potential to protect public health.
When the human health risk assessment/risk management paradigm was developed, it did not explicitly include a “problem formulation” phase. The concept of problem formulation was first introduced in the context of ecological risk assessment (ERA) for the pragmatic reason to constrain and focus ERAs on the key questions. However, this need also exists for human health risk assessment, particularly for cumulative risk assessment (CRA), because of its complexity. CRA encompasses the combined threats to health from exposure via all relevant routes to multiple stressors, including biological, chemical, physical and psychosocial stressors. As part of the HESI Risk Assessment in the 21st Century (RISK21) Project, a framework for CRA was developed in which problem formulation plays a critical role. The focus of this effort is primarily on a chemical CRA (i.e., two or more chemicals) with subsequent consideration of non-chemical stressors, defined as “modulating factors” (ModFs). Problem formulation is a systematic approach that identifies all factors critical to a specific risk assessment and considers the purpose of the assessment, scope and depth of the necessary analysis, analytical approach, available resources and outcomes, and overall risk management goal. There are numerous considerations that are specific to multiple stressors, and proper problem formulation can help to focus a CRA to the key factors in order to optimize resources. As part of the problem formulation, conceptual models for exposures and responses can be developed that address these factors, such as temporal relationships between stressors and consideration of the appropriate ModFs.
The HESI-coordinated RISK21 roadmap and matrix are tools that provide a transparent method to compare exposure and toxicity information and assess whether additional refinement is required to obtain the necessary precision level for a decision regarding safety.
The HESI-led RISK21 effort has developed a framework supporting the use of twenty-first century technology in obtaining and using information for chemical risk assessment.