The document discusses the Threshold of Toxicological Concern (TTC) concept, which is used within the European Union's REaCh regulation for chemical safety assessment. The TTC is a method to estimate safe levels of human exposure to chemicals, based on toxicological data and chemical structures of a large number of substances. The TTC concept was initially applied to flavoring substances, and a guidance document for data requirements of new flavoring substances has been issued by the CEF Panel.
The TTC concept is not applicable to substances that do not have sufficient toxicological data or are not included in currently available databases. The document also mentions that endocrine-disrupting chemicals and pesticide metabolites are not evaluated using the TTC approach. The TTC values, as proposed by Kroes et al. (2004), can be used to waive testing of a substance based on exposure assessment scenarios. however, there are no specific threshold references mentioned in the guidance document.
The document also refers to the historical development of the TTC concept, which includes two approaches: the general TTC concept and a tiered TTC concept related to structural information and/or metabolic and toxicological data for individual substances.
Citation
Nielsen and Larsen, “The Threshold of Toxicological Concern (TTC) Concept: Development and Regulatory applications.”
