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Ecotoxicological information

Sediment toxicity

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Description of key information

No ecotoxicity data for the sediment compartment is available for the diquat C16-18 and the PNEC for the benthic compartment is therefore calculated applying the Equilibrium Partitioning Method (EPM).

Key value for chemical safety assessment

Additional information

In the absence of measured data the PNECsed can provisionally be calculated using the equilibrium partitioning method (EPM). According to the TGD this method uses the PNECaquatic and the sediment/water partitioning coefficient as inputs. However, since the available PNECaquatic is based on the bulk concentration present in surface water a re-calculation is necessary first:

PNECaquatic, dissolved = PNECaquatic bulk/ (1 + Kpsusp* SUSPwater* 10-6)

Where:

PNECaquatic bulk  =  13.98 µg/L

Kpsusp                       =      100000 L.kg-1

SUSPwater                  =      15 mg.L-1(EU, TGD2003, REACH R.16)

The PNECsedis then calculated using the equations detailed in the TGD:

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

Where:

PNECaquatic dissolved =  5.59 µg/L

Ksusp-water                  =      25000.9 m3.m-3

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

                                     PNECsed-EPM                     = 12.16 mg/kg ww = 55.93 mg/kg dw including correction for additional exposure via ingestion.