Quaternary ammonium compounds, C20-22-alkyltrimethyl, chlorides

Endpoint summary

Description of key information

Cationic surfactants like C20/22 ATQ are difficult to test in the aquatic compartment as they are sorbing strongly to solids. Normally the analytical recovery of the cationic 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 neglectable 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. C20/22 ATQ 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 PNEC_aquatic, together with the chronic fish study and the E_rC10 Algae which results in an Application 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 C20/22 ATQ - most relevant Acute and Chronic aquatic tests (active ingredient (a.i.))

Test type	Test medium	Species	Effect			Guideline
Acute fish	River water	Danio rerio	LC50 (96h)	3.5	mg/l	OECD 203
Acute Daphnia	River water	Daphnia magna	EC50 (48h)	1.4	mg/l	OECD 202
Algae	River water	Desmodesmus subspicatus	ErC50 (72h)	3.4	mg/l	OECD 201
Sludge respiration inh	Tap water	Non-adapted sludge	EC50 (3h)	43	mg/l	OECD 209
Chronic fish	River water	Danio rerio	NOEC (9d)	240	µg/L	OECD 212
Chronic daphnia	River water	Daphnia magna	NOECrepro (21d)	119	µg/L	OECD 211
Chronic Algae	River water	Desmodesmus subspicatus	ErC10 (72h)	780	µg/L	OECD 201