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Environmental fate & pathways

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Hydrolysis

The stability (hydrolysis) of C16 Alkylamidopropyltrimethylammonium Chloride was calculated using EPIWIN, HYDROWIN v2.00. Hydrolysis is not to be expected under environmental conditions: the calculated hydrolysis half-life time (t1/2) was found to be >1 year.

 

Biodegradation

The ready biodegradability of C16 Alkylamidopropyltrimethylammonium Chloride was determined with a non-adapted activated sludge over a test period of 28 days in the Modified Sturm Test according to OECD 301 B.

The test item was tested at a concentration of 16 mg/L with 2 replicates corresponding to a carbon content (TOC) of 10.8 mgC/Lin the test vessels with and without Humic acid. The test vessels were incubated at low light conditions and at a temperature of 22 ± 2°C.

The biodegradation of the test item was followed by titrimetric analysis of the quantity of CO2 produced by the respiration of bacteria. The degradation was stopped on day 28 by acidification of the test solutions. The last titration was made on day 29 after residual CO2 had been purged from the test solutions over a period of 24 hours. The percentage CO2 production was calculated in relation to the theoretical CO2 production (ThCO2) of the test item. The biodegradation was calculated for each titration time.

To check the activity of the test system sodium benzoate was used as functional control. The percentage degradation of the functional control reached the pass level of 60% within 8 days and a maximum biodegradation of 84% on day 16. The functional control with Humic acid reached the pass level of 60% within 13 days and a maximum biodegradation of 67% on day 28.

In the toxicity control containing both test and reference item a biodegradation of 67% was determined within 13 days, with 95% after 28 days. The biodegradation of the reference item was not inhibited by the test item in the toxicity control. In the toxicity control with humic acid a biodegradation of 57% was determined within 13 days, with 70% after 28 days.

Both test item replicates without humic acid reached the 10% level (beginning of biodegradation) within 6 days. Both test item replicates reach the 60% pass level within 13 days. The mean biodegradation on day 28 was 100%.

Both test item replicates with humic acid reached the 10% level (beginning of biodegradation) within 6 days. Both test item replicates reach the 60% pass level within 16 days. The mean biodegradation on day 28 was 72%.

The replicates without humic acid did show better results and are therefore used to evaluate the study. The replicates with humic acid did also fulfil the 10-day-window, but only for the mean of the replicates.

Under the test conditions the test item is classified as readily biodegradable within the 10-day-window and within the 28 day period of the study.

Simulation test

The elimination and primary degradation of the test item C16 Alkylamidopropyltrimethylammonium Chloride in an activated sludge unit was determined according to OECD guideline 303 A in a continuously operating laboratory activated sludge unit simulating the activated sludge process.

Based on the analysis of the test item in the effluent, the mean elimination rate at the plateau phase in relation to the total influent concentration was calculated. The elimination of the test item in the effluent was 99.29 % (95 % CI: 99.18-99.40) in a continuously operating activated sludge unit. The mean load of the test item in the sludge during the plateau phase was 0.12 % (95 % CI: 0.06 - 0.18). The mean concentration of the test item in the sludge during the plateau phase was 9.96 µg/g DW (95 % CI: 5.88 - 14.03). lt can be concluded that the main elimination process of the test item in a sewage treatment plant is biodegradation.

 

Adsorption/Desorption

According to REACH, Annex VIII, column 2 the study does not need to be conducted if based on the physicochemical properties the substance can be expected to have a low potential for adsorption (e.g. the substance has a low octanol water partition coefficient). A value of 2.49 was determined for the octanol/water partition coefficient.