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Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

Cationic surfactants like the submission substance and the supporting substance C20/22 ATQ (CAS 68607 -24 -9)

are difficult to test in the aquatic compartment as they are sorbing strongly to solids. Normally the analytical recovery of the cation is good at the beginning of the test but at the end of the test recovery is often below the acceptable minimum recovery. Lowering of the recovery could be related to sorption of the substance to the test container walls but sorption occurs also to the negatively charged surface of the test organism e.g. of algae or fish. Substance sorbed to the organism means the substance is still present in the test system and if it is demonstrated that sorption to the test container walls is negligible the nominal concentrations at test begin can be used to derive the L(E)Cx values. If this is not the case the geometric mean of the concentration at the test begin and end can be used.

Aquatic studies not addressing this difficult behaviour of cationics in aqueous test systems may result in effect values being unrealistically low.

For all three trophic levels (fish, daphnia and algae) acute and chronic data are available. The supporting substance C20/22 ATQ (CAS 68607 -24 -9) is most toxic to daphnia. For daphnia one acute and one chronic study is available. The chronic 21d Daphnia reproduction study is the basis for the PNECaquatic, together with the chronic fish study and the ErC10 Algae which results in an assessment factor of 10. 

In Table 6.1-1 the different test results which are most relevant are given. All aquatic studies were carried out with active ingredient (a.i). 

Table 6.1-1    Test results from supporting substance C20/22 ATQ - most relevant Acute and Chronic aquatic tests (active ingredient (a.i.))

Test type

Test medium






Acute fish

River water

Danio rerio

LC50 (96h)



OECD 203

Acute Daphnia

River water

Daphnia magna

EC50 (48h)



OECD 202


River water

Desmodesmus subspicatus

ErC50 (72h)



OECD 201

Sludge respiration inh

Tap water

Non-adapted sludge

EC50 (3h)



OECD 209








Chronic fish

River water

Danio rerio

NOEC (9d)



OECD 212

Chronic daphnia

River water

Daphnia magna

NOECrepro (21d)



OECD 211

Chronic Algae

River water

Desmodesmus subspicatus

ErC10 (72h)



OECD 201

In oder to demonstrate that the change of anion does not negatively influence the toxicity of the submission substance (anion methosulfate) compared to the structural analogue 220/22 ATQ (anion chloride), data from an acute fish toxicity test is presented. These data, as summarised in an EU Risk Assessment Report, show absence of aquatic toxicity of monomethyl sulfate (LC50 (96 h) >10000 mg/L).