S13-5 Exposure assessment to multiple chemicals and future mixture testing

Every day, we are exposed to multiple chemicals by several routes of exposure: diet, inhalation and dermal contact. Until recently, risk assessment is mostly performed separately for each chemical, considering only a single route of exposure. However, this simplified risk assessment does not take into account the effect that chemicals may have on each other and their effect on the same target organ. According to EU Regulation, EFSA is responsible to establish the methodology for combined exposure to multiple pesticides. Recently, EFSA has published the outline of the methodology on the EFSA website, including four EFSA opinions on how based on their toxicological profile and EFSA guidance on how to perform the exposure assessment. EFSA started grouping pesticides into cumulative assessment groups based on their toxicological profile for all pesticides affecting the nervous system and all pesticides affecting the thyroid gland. EFSA noticed that relevant information on the toxicity of the chemical is not always available. Consequently, EFSA applied a precautionary principle in their grouping and it was noticed that refinements are possible when data on toxicity becomes available. To this end, the new European funded project EuroMix will apply several in-silico and in-vitro tools to mixtures of chemicals that can affect the liver, the endocrine system, and the development stage. A number of test systems, including omics technology and classic toxicological testing, will be explored. The most promising tests for mixtures will be verified against results from animal studies. Once validated, the tests will be used to collect information needed to refine the risk assessment. Data and models will become available in a web-based platform for all European countries and stakeholders.