Amines, N-(C18-unsatd. alkyl)trimethylenedi-, ethoxylated

Endpoint summary

Additional information

Ecotoxicity testing with cationic surfactants is complicated as these substances tend to sorb to negatively charged surfaces like glassware and test organisms. The reproducibility of these tests is in general poor. When cationic surfactants enter the environment they will be immediately sorbed to the suspended matter and DOC present in the environment. The toxicity will due to this sorption be mitigated. The degree of this mitigation is however poorly predicted with the currently available exposure models (e.g. EUSES) as they only predict sorption based on hydrophobic interaction with organic matter where the main sorption of these substances will be due to ionic interaction. To increase the reproducibility of the ecotoxicity testing and to compensate for the deficiency of the bioavailability modeling tests have been performed with river water. To ensure the representativeness of the test results, realistic worst-case river water (DOC close to 3 mg/L and suspended matter close to 15 mg/L) has been used. These river water studies should therefore be considered as higher tier studies. This approach is also applied in EU risk assessments of DODMAC and primary fatty amines and is known as the Bulk-approach (ECETOC TR88 2003).

In order to classify a standard laboratory toxicity study as valid, it is of particular importance that - besides information on test substance, test method/conditions and test organism used - suitable precautions are taken to prevent the loss of test substance by adsorption and that exposure concentrations are based upon measured levels.

For ecotoxicity tests performed using the bulk-approach, however, adsorption to suspended matter and DOC is acceptable and only adsorption to glassware should be accounted for. For a valid bulk approach test the concentration-effect relationship should be based on the sum of adsorbed and dissolved substance in the volume of the medium tested. One of the advantages of the bulk approach tests with these difficult substances is that in the presence of suspended matter, humic acids and/or algae, the residual sorption to glassware will be negligible. The observed sorption to glassware was 4% in the algae test at a test concentration of 320 µg/L and 9% in the long-term daphnia test at a test concentration of 270 µg/L at the end of both tests. The results of these bulk approach tests are therefore much easier to interpret, more environmental realistic, and when compared to PEC_bulk clearly provide a more appropriate assessment of risks for the environment. All effect values given are therefore based on the nominal test item concentrations.

The results as observed for algae according to OECD TG 201, for daphnia according to OECD TG 211 and for Micro-organisms according to OECD TG 209 for both the oleyl and tallow based ethoxylated diamine are used to support the read across of fish, acute daphnia and long-term earthworm results from the source chemical tallow based ethoxylated diamine to the target chemical oleyl based ethoxylated diamine. The two ethoxylated diamines under consideration consist of carbon, hydrogen, oxygen and nitrogen only. The basic structure includes a hydrocarbon chain with an 3EO ethoxylated 1,3 -propanediamine group at the end of the chain. The main difference consists of differing chain lengths (C_{12 -18}) and slight variations in the degree of saturation in the alkyl chain. The available ecotox data reveal a comparable toxicity independent of the alkyl chain length or saturation. Therefore a read-across approach is considered justified.

An overview of the most relevant results for both is presented in the table.

	Oleyl based ethoxylated diamine  CAS number: 1268344-02-0	Tallow based ethoxylated diamine CAS number: 1290049-56-7
Fish OECD TG 201		96h-LC50 = 0.13 mg/L, OECD water 96h-LC50 = 0.17 mg/L, OECD water
Daphnia magna OECD TG 202	21d-EC50 = 421 µg/L, river water	48h-EC50 = 0.31 mg/L, OECD water 21d-EC50 = 240 µg/L , river water
Daphnia magna OECD TG 211	21d-EC50 = 421 µg/L, river water 21d-ErC10 = 91.3 µg/L, river water 21d NOEC = 270 µg/L, river water	21d-EC50 = 240 µg/L, river water 21d-ErC10 = 200 µg/L, river water 21d NOEC = 270 µg/L, river water
Pseudokirchneriella subcapitata OECD TG 201	72h-ErC50 = 256 µg/L, river water 72h-ErC10 = 86.3 µg/L, river water	72h-ErC50 = 160 µg/L, river water 72h-ErC10 = 100 µg/L, river water
Microorganisms OECD TG 209	3h-EC50 = 56 mg/L 3h-EC10 = 14 mg/L	3h-EC50 = 56 mg/L 3h-EC10 = 16 mg/L
Earthworm OECD TG 222		56d-NOEC = 500 mg/kg dw