Exposure to multiple chemicals : when and how to assess the risk from pesticide residues in food

Exposure to multiple pesticide residues derived from food is a common occurrence in the general population. Levels of exposure are usually low, below the effective doses. Interactions, such as potentiation and synergism, are not expected to occur at these doses. Available evidence indicates that risk assessment should be carried out for mixtures containing compounds with the same mode of action, since their effects are expected to cumulate. Several methods are available to assess this cumulative risk that differs in the mathematical expression of the data, in the level of uncertainty and transparency, in the requirement of efforts and resources.