Specific concentration limit as a tool for classifying mixtures by human health hazards. Part 1. Characteristics, scope, regulatory aspects of implementation in the EAEU

The Globally Harmonized System of Hazard Classification and Labeling of Chemicals (GHS) makes it possible to classify mixtures by hazardous properties using the calculation method and cut-off values/concentration limits (CV/CL). However, the CV/CL of hazardous components adopted in the GHS do not take into account their individual toxicological profile, which can lead to either underestimation or overestimation of the hazard posed by the entire mixture. To overcome these shortcomings of the GHS and to classify mixtures more accurately, specific concentration limits (SCL) are used along with CV/CL in the European Union (EU). The article presents: the characteristics and scope of SCL in accordance with the types of human health hazards included in the GHS, the possibility of setting numerical values of SCL higher than CV/CL, priority in their joint use and the mathematical criterion underlying the application of SCL. Example classification of model mixtures corrosive/irritative to skin based on SCL of their components is considered in a situation when the additive approach is applicable. The obtained results are compared with the classification based on the CV/CL without considering the SCL. Advantages and difficulties of SCL implementation in order to protect citizens from adverse effects of chemical factors while maintaining required production volumes in the chemical industry are discussed from the perspective of a mixture manufacturer and a regulatory authority. The author evaluated the possibility of SCL implementation for toxicological assessment of mixtures, considering the approved technical regulations of the EAEU «On the safety of chemical products» (TR EAEU 041/2017) and the standards that have come into force.