There is an increasing need to develop harmonised frameworks and methods for the risk assessment of combined exposure to multiple chemicals. A number of activities have already been undertaken by EFSA, notably in the fields of pesticides and contaminants. This project aims at searching for, reviewing, collecting and synthesizing the published data on combined effects of multiple chemicals in more than 50 species of veterinary and ecological relevance, using extensive literature searches. The taxonomical hierarchy for the literature searches was very wide ranging from bacteria, fungi, invertebrates and vertebrates (amphibians, reptiles, birds, cats, cattle, deers, goats, horses, minks, pigs, sheep, fishes, spiders, ephemeroptera, hymenoptera, diptera, earthworms, Caenorhabditis elegans, molluscs, mites, crustacea, odonata, orthoptera, collembola, coleoptera, blattids, plants, cyanobacteria, proteobacteria, fungi). In vivo toxicity data were extracted from 199 publications representing 3,074 individual studies on pesticides, environmental contaminants, food-related products, hormones, metals, mycotoxins and pharmaceuticals. The magnitudes of interaction following acute and chronic exposure to multiple chemicals were consolidated via meta-analysis and expressed as mean effect ratios between single and multiple chemicals. Overall, this report illustrates how systematic published data collection and synthesis can support hazard characterisation of combined toxicity of multiple chemicals. Further work is proposed to compare the toxicity datasets for which statically significant interactions have been reported with chemical-specific reference points from EFSA's chemical hazards database. These analyses will allow testing the sensitivity of the toxicological endpoints (e.g. acute versus chronic effects, mortality versus biochemical parameters etc…), the dose dependency of the toxicological interactions and the potential use of the methodology in ecological risk assessment of multiple chemicals. © LASER Analytica, 2015.
