Expanding the use of a science-based tool for toxicological health risk assessment objectives
Task Force Information
The Task Force aims to strengthen the scientific fundamentals for TTC and to expand its applicability as a risk assessment tool for substances to which humans are exposed at low levels.
Task Force Members
Uncertainty in Hazard Assessment: a Comparison of TTC versus Chemical-Specific Approaches- Ongoing -
The review will aid to develop knowledge and understanding of different stakeholders about the sources of uncertainty and allow a conclusion if and if so, how much additional uncertainty may be associated with the application of the TTC approach as compared to substance-specific risk assessment. Such understanding will enable appropriate communication of uncertainty, and would also allow to design future activities to minimize potential additional uncertainties.
Building cumulative assessment groups for combined exposure risk assessment based on TTC thresholds or read-across - Ongoing -
The aim of this working group is to solidify the scientific basis for combined toxicity screening assessment using TTC threshold values, as there is a growing need for screening and prioritisation risk assessment on combinations of compounds in regulatory contexts of poorly characterized compounds at low exposure levels. These might be metabolites/impurities of pesticides, chemicals, or biocides, food contact material migrants, packaging materials, or process-related contaminants.
Uncertainty in Hazard Assessment: a Comparison of TTC versus Chemical-Specific Approaches
Background and Objectives
The probabilistic approach using the genotoxicity and non-cancer (Cramer class) Thresholds of Toxicological Concern (TTC) is often perceived as accepting a higher risk than traditional risk assessments.
However, robust scientific activities to describe the sources of uncertainty within the TTC approach have not yet been conducted or published.
The Expert Group examines how much uncertainty may be associated with the application of the TTC approach, compared to a substance-specific risk assessment. The group expects to produce two reviews: an initial focus on qualitative description and ranking of the identified sources of uncertainty. A subsequent quantitative assessment of the remaining quantifiable uncertainties.
Expert Group Members
Building cumulative assessment groups for combined exposure risk assessment based on TTC thresholds or read-across
Background and Objectives
Develop scientific approaches for refinement of TTC-based co-exposure risk assessments, using real-world case examples and focus on data-poor substances and poorly characterized compounds at low exposure levels (metabolites/impurities of pesticides, chemicals, or biocides, food contact material migrants, packaging materials, or process-related contaminants). Solidify the scientific basis for combined toxicity screening assessment using TTC threshold values
Provide guidance on methods to predict specific toxicity or general toxicological similarity to enable grouping into cumulative assessment groups. Develop a workflow relevant for different regulations for coexposure risk assessment based on TTC thresholds, possibly combined with specific read-across groups. Evaluate if and in which cases it might be sufficient to compare the TTC thresholds to individual coexposure component levels and in which cases all or some coexposure components should be added.
Expert Group Members
Thresholds of Toxicological Concern for Cosmetics-Related Substances: New Database, Thresholds, and Enrichment of Chemical Space
Origin of the TTC Values for Compounds that are Genotoxic and/or Carcinogenic and an Approach for their Re-Evaluation
Critical Reviews in Toxicology 2017. Commissioned by the Threshold of Toxicological Concern (TTC) Task Force.
Assessing the Safety of Cosmetic Chemicals: Consideration of a Flux Decision Tree to Predict Dermally Delivered Systemic Dose for Comparison with Oral TTC (Threshold of Toxicological Concern)
Regulatory Toxicology and Pharmacology. 2016;76:174-186. Commissioned by the Threshold of Toxicological Task Force.
The Role of Hazard- and Risk-Based Approaches in Ensuring Food Safety
Trends in Food Science & Technology. 2015;46(2) Part A:176-188. Supported by the following task forces: Emerging Microbiological Issues, Food Allergy, Food Intake Methodology, Novel Foods and Nanotechnology, Process Related Compounds and Natural Toxins, Risk Analysis in Food Microbiology, and Threshold of Toxicological Concern.
Evaluation of the Threshold of Toxicological Concern (TTC) – Challenges and Approaches
Regulatory Toxicology and Pharmacology. 2013;65(1):168-177. Commissioned by the Threshold of Toxicological Concern Task Force.