Verordnung (EG) Nr. 1907/2006 (REACH)
PNEC is used extensively in Europe by the European Chemicals Agency, the Registration, Evaluation, Authorisation and Restriction of Chemicals program and other toxicology agencies to assess environmental risk. PNEC values can be used in conjunction with predicted environmental concentration values to calculate a risk characterization ratio (RCR), also called a Risk Quotient (RQ). RCR is equal to the PEC divided by the PNEC for a specific chemical and is a deterministic approach to estimating environmental risk at local or regional scales. If the PNEC exceeds the PEC, the conclusion is that the chemical poses no environmental risk.