Reaction products of 2-[[2-(dimethylamino)ethyl]methylamino]ethanol di(hexanoate) and ethyl oxirane

Endpoint summary

Additional information

The ready biodegradability of the test item was determined with non-adapted activated sludge in the Manometric Respirometry Test for a period of 28 days according to OECD 301F. The test item concentration selected as appropriate was 25 mg/L, corresponding to a ThOD of 52.3 mg O2/L per test vessel. The oxygen was depleted by the respiration of bacteria and the degradation was followed by measuring the oxygen concentration. The biodegradation rate is therefore expressed as the percentage BOD (biological oxygen demand) and was calculated for each study day.

 

Summary of the First Study

The mean oxygen depletion in the inoculum control was 30.3 mg O2/L on day 28.

In order to check the activity of the test system sodium benzoate was used as functional control. The pass level > 60 % was reached within 3 days. The biodegradation reached a maximum of 84 % degradation on day 15.

In the toxicity control containing both test and reference item 68 % degradation occurred within 14 days. After 28 days the biodegradation came to 75 %. The degradation of the reference item was not inhibited by the test item.

For the test item both replicates reached the 10 % level (beginning of biodegradation) within 2 days. The 60 % pass level was not reached until test end. The mean biodegradation on day 28 was 45 % (1st replicate 31 % and 2nd replicate 58 %). Due to a diffenrence of more than 20% beween the test item replicates, a second test was conducted.

 

Summary of the second study

 

The mean oxygen depletion in the inoculum control was 24.0 mg O2/L on day 28.

In order to check the activity of the test system sodium benzoate was used as functional control. The pass level > 60 % was reached within 3 days. The biodegradation reached a maximum of 97 % degradation on day 27.

In the toxicity control containing both test and reference item 66 % degradation occurred within 14 days. After 28 days the biodegradation came to 81 %. The degradation of the reference item was not inhibited by the test item.

For the test item both replicates reached the 10 % level (beginning of biodegradation) within 1 day. The 60 % pass level was reached by the first replicate on day 18 and was missed by the second test item replicate. The mean biodegradation on day 28 was 58 % (first replicate 73 % and second replicate 43 %).

 

The repeatedly divergent results for the test item replicates indicate that – although soluble – the test item seems to have inherent properties that only under ideal conditions allows for biodegradation within the “ready” limits. Therefore, it is assumed, that these inherent properties of the test item, minimal differences in the bacterial composition of the inoculum and differences in the progress of adaptation during the studies for the different constituents are decisive for the outcome of the biodegradation of the test item, resulting in difference > 20 % between the test item replicates. Nevertheless, the test item has to be attributed a greater potential of biodegradability than the classification as “not readily biodegradable” reflects.

The test item is classified as not readily biodegradable within the test period of 28 days.