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Sediment toxicity

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Reference
Endpoint:
sediment toxicity: long-term
Data waiving:
exposure considerations
Justification for data waiving:
other:

Description of key information

No studies on the toxicity of the substance to Benthic-organisms are available. These studies do not need to be conducted because direct and indirect exposure of the benthic compartment does not occur – [exposure considerations]

Key value for chemical safety assessment

Additional information

No studies on the toxicity of the substance to benthic-organisms are available. These studies do not need to be conducted because direct and indirect exposure of the benthic compartment in the EU does not occur – [exposure considerations]. No risks are therefore calculated for benthic compartment.

Despite of the absence of direct or indirect exposure of the benthic compartment the PNECsed was calculated using the equilibrium partitioning method.

It has been noted that the guidance on information requirements and chemical safety assessment(v.4.0, June 2017), Chapter R7b states that “EPM is based on sorption to organic matter and that it therefore, cannot be used for some classes of substances, e.g. when binding behaviour is not driven by lipophilicity (e.g. aromatic amines forming covalent bonds to sediment components, ionisable substances, surface active substances).

To evaluate if the EPM can be used conservatively for cationic surfactants, results available from long term daphnia and sediment tests for 8 different cationic surfactants were used.

The results of the sediment studies were compared to the EPM calculated sediment effects. For 5 out of the 8 the EPM predicted the EC10 for sediment organisms more conservatively than what was observed in the sediment test without applying the additional safety factor of 10 to compensate for ingestion. After including the additional AF (of 10), for all 8 substances the EPM was found to be more conservative than the observed sediment toxicity. The Kp sups-water for these substances ranged from 1040 L/kg to 20100 L/kg. See table below:

Name CAS number Long term daphnia NOEC/EC10 dissolved (µg/L) Kpsusp-water (L/kg) AF for ingestion Observed Benthic NOEC/EC10 (mg/kg dw) Predicted Benthic NOEC/EC10 using the EPM (mg/kg dw) Ratio observed/predicted NOEC/EC10 
Amines, N-C16-18-alkyl (evennumbered) propane-1,3-diamine 133779-11-0  315.08 1040 y 86 32.88 2.62
1,3-Propanediamine, N-[3-((C11-14, C13-rich)oxy)propyl]- branched acetate 102047-27-8 87.37 4020 y 134 35.15 3.81
Quaternary ammonium compounds, C20-22-alkyltrimethyl, chlorides 68607-24-9 124.61 1813.5 y 62.5 22.64 2.76
2,2'-(octadec-9-enylimino)bisethanol 25307-17-9 9.62 7460 n 101.2 71.82 1.41
Quaternary ammonium compounds, di-C12-18-alkyldimethyl, chlorides 68391-05-9 8.55 16800 n 320 143.61 2.23
C16-18-(even numbered, C18-unsaturated)-alkylamines 68037-95-6 12.73 1394 n 188 17.80 10.56
Quaternary ammonium compounds, di-C10-alkyldimethyl, chlorides 7173-51-9 14.00 20098.8 n 530 281.43 1.88
C12-16 alkyldimethylbenzylammonium chloride 68424-85-1 4.15 16778.8 n 520 278.53 1.87

New data sediment and daphnia data on cationic surfactants will be added to the dataset to in the end generate even more convincing support which will be reported according to the appropriate ECHA guidance.

Finally it should be noted that for all substances in this table real measured sorption data are used which are not normalized to the organic matter content of the soils and that for both sediment and soil the same Kd is used (See EU risk assessment primary alkyl amines).