3.3.: Step 3: Identification of the PNEC

3.3.1. Based on the available information, the PNEC for each environmental sphere shall be established. The PNEC may be calculated by applying an appropriate assessment factor to the effect values (e.g. LC50 or NOEC). An assessment factor expresses the difference between effects values derived for a limited number of species from laboratory tests and the PNEC for the environmental sphere ( 32 ).
3.3.2. If it is not possible to derive the PNEC, then this shall be clearly stated and fully justified.