Mixture toxicity evaluation in modern toxicology

Abstract

People of all ages and developmental stages are regularly exposed to a wide range of chemicals through a number of exposure routes, making dangerous environmental chemical exposure sources predominant. Up to this point, only one chemical has had its long-term toxicity assessed for substances that were used to determine suitable reference doses and assumed safe limits. Unfortunately, these traditional long-term safety evaluations make it challenging for risk assessment-based regulation to provide accurate permissible levels for individual chemicals due to the magnitude of the real-life exposure to a large number of environmental chemicals, the complexity of mixtures, and non-linearity. This chapter aims to provide an overview of the existing regulatory procedures used in the evaluation of mixture toxicity along with an analysis of novel methodologies that have been proposed and may be able to more accurately anticipate a chemical's toxicity in the context of actual exposure scenarios. To improve population protection, it is obvious that the focus should shift from single chemical risk assessment to cumulative risk assessment.