Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

In a study conducted according to OECD guideline 310 (corrected 2014) Oleic-acid based IQAC, DMS quaternised was tested for biodegradability by CO2 generation in sealed vessels. Degradation failed to pass the 10 -day window and no reasonable degradation occured during the 60 days of the experiment.

The validity criteria were fulfilled according to the guidelines:

·   The degradation of the functional control reached the pass level of 60% within 7 days (validity criterion: > 60% after 14 days).

·   The maximum amount of TIC present in the inoculum controls (C1 - C5) on day 28 was1.06 mg C/L and 1.12 mg C/L on day 60 (validity criterion: TIC < 3 mg C/L).

Thus, the test item is classified as not readily biodegradable within the 60 day period of the present study.

Oleic-acid based IQAC, DMS quaternised proved to be not readily biodegradable (<=12.7% degradation after 28 d) in a test conducted according to OECD Guideline 301B and US EPA Method 796.3260. In a static test according to DIN 38412, Part 25, the closely related partially unsaturated IQAC, DMS quaternised (CAS 86088-85-9) proved to be inherently biodegradable, > 90 % based on O2consumption after 28 d.The only difference to IQAC based on Oleic-acid, DMS quaternised is the source of the fatty acid moiety resulting in slight differences in number and position of the C=C double bonds. Further reliable tests of the read across substancePartially unsaturated IQAC, DMS quaternised (CAS 86088-85-9) on ready biodegradability underline that the substance to be registered is inherently biodegradable.

The differences between the results for hydrolysis and biodegradation rates may be due to the test design. In the study for hydrolysis, Oleic-acid based IQAC, DMS quaternised was dissolved in acetonitrile to prepare the stock solutions and then the test solutions were prepared by adding small amounts of the stock solution to the test solution. By this procedure the test item might have been more dispersed and therefore more susceptible for hydrolysis than in the biodegradation studies, where dispersions in water were used.

However, from the studies on hydrolysis and biodegradation it can be concluded that Oleic-acid based IQAC, DMS quaternised is susceptible to hydrolysis and biodegradation and will not persist in the environment.

The above results are confirmed by a study conducted similar to OECD Guideline 303 A (Simulation Test - Aerobic Sewage Treatment. A: Activated Sludge Units), partially unsaturated IQAC, DMS quaternised (CAS 86088-85-9) was eliminated for > 90% in a modified activated sludge unit. The effluent of the laboratory scale activated sludge unit was used for long-term ecotoxicological tests with Daphnia magna and algae. The degradation capacity of the sludge units was kept high and the nitrification of the sludge unit was therefore > 95%. The ammonium concentration was < 2 mg/L in the effluent.

Therefore simulation testing of oleic-acid based IQAC in sediments and biodegradation testing oin soils is not necessary. In addition the oleic-acid based IQAC hydrolyses rapidly in water at environmental pH (see 4.1.1.1).

Justification for read-across:

The structural similarities between the source and the target substances presented above are the basis for the read-across hypothesis. Adequate, reliable and available scientific information indicates that the source and target substances have similar physicochemical properties, ecotoxicological and toxicity profiles and thus support the read-across hypothesis.

Both substances are UVCB substances, produced by a similar process resulting in main constituents of the same structure, varying in the degree of saturation and chain length (C16 and C18 and mainly C18, for source and target substance, respectively). Given the underlying identical generic structure (outlined in chapter 1 and 2), similar absorption following oral or dermal uptake and the same metabolic patterns are expected for source and target substance. The findings from toxicokinetic data confirm that the discussed IQAC source and target substances are only poorly absorbed after oral application and rapidly excreted. There was no tendency for accumulation of the substance in the body of the test animals.

In conclusion the results obtained from source substance (partially unsaturated IQAC, DMS quaternised) are considered a reliable source to cover endpoints of the target substance (oleic-acid based IQAC, DMS quaternised).

 A more detailed justification for read-across is outlined in a separate document:

“Justification for read-across - toxicological information”, is attached to the endpoint summary acute toxicity and provided in chapter 13 of Technical dossier.