SDS Studio™Definition: The PNEC (predicted no-effect concentration) is the concentration of a substance below which no adverse effects on an environmental compartment are expected.
PNECs are given for freshwater, marine water, sediment, soil and sewage treatment plants. They come from the registration dossier and appear in SDS section 8.1.
PNECs support the environmental risk assessment, while classification for aquatic toxicity uses EC50, LC50 and NOEC values in section 12.
A PNEC is derived with assessment factors. Aquatic classification under CLP is based on toxicity data, not on the PNEC.