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Description of key information

According to column II of annex IX of the REACH legislation the endpoint can be waived if the substance is readily biodegradable and has no adsorption potential to soil (eg low log Koc or Kow).

Key value for chemical safety assessment

Additional information

In the absence of measured data the PNECsed can be provisionally calculated using the equilibrium partitioning method (EPM). According to REACH guidance R.16 this method uses the PNECaquatic and the sediment/water partitioning coefficient as inputs. The Koc value for MCAA is 2.1 L/kg. Considering the low pKa of MCAA it was decided to use the Koc of SMCA (CAS no 3926 -62 -3) of 0.73 L/kg for predicting the partitioning in the environment. A Koc of 0.73 L/kg corresponds with a Kd for suspended matter of 0.073 L/kg and a suspended matter-water partition coefficient of 0.918 m3/m3

The PNECsedis then calculated using the equations detailed in the REACH guidance:

                                     PNECsed                         =   Ksusp-water* PNECaquatic dissolved* 1000 * 1 / RHOsusp

                  Where:        PNECaquatic dissolved      =      0.7 µg/L

                                  Ksusp-water                        =      0.918 m3.m-3

                                     RHOsusp                        =      1150 kg.m-3(TGD, eq. 18)

                                     PNECsed-EPM               = 0.56 µg/kg ww

                                                                          = 2.57 µg/kg dw