predicted environmental concentration predicted environmental concentration calculated value of a chemical in the environment on the basis of exposure models such as the european union system for the evaluation of substances (euses). used in the context of chemical safety assessments (csa) and referenced in chemical safety reports (csr). pecs may be compared with measured environmental concentrations (mec) if available. this article is issued from wikipedia. the text is licensed under creative commons - attribution - sharealike. additional terms may apply for the media files.