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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

The  TEA-Esterquat C8-18 and C18 unsat. is readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

No degradation result is available for the esterquat C8-18 and C18 unsat. . However, there are several reliable studies available for biodegradability screening tests of the esterquats: C16-18, C16-18 and C18 unsat. as well as for C18/C18unsat. which can be used for read across.

Based on the large number of positive results in terms of readily biodegradability for the different esterquat types, it is concluded that also the esterquat C-18 is readily biodegradable.

Aerobic biodegradation

There are several reliable studies available for biodegradability screening tests of the TEA-Esterquats. The ready biodegradation of the test substance fully saturated TEA-Esterquat, hardened was investigated in a key study (Clariant GmbH, 2002) conducted according to OECD 301B (1992) over a period of 28 days and using activated sludge municipal sewage treatment plant as inoculum. The biodegradation rate was determined by measurement of CO2 evolution. Inoculum blank, procedural/functional control with the reference substance sodium and toxicity control using 20.8 mg/L sodium benzoate and 20.9 mg/L test substance were performed.

The test substance was determined to be readily biodegradable (65 - 66 % after 28 d; according to the revised OECD Guidelines the 10-d window should not be applied to interpret the results of a test with a mixture of structurally similar chemicals).

 

In addition, the ready biodegradation of partially saturated TEA-Esterquat was investigated in a study (Kao, 1997) conducted according to OECD 301 B (1992) over a period of 28 days and using activated sludge from a municipal wastewater treatment plant as inoculum. The biodegradation rate was determined by measurement of CO2 evolution. Inoculum blank, procedural/functional control with the reference substance sodium benzoate, and toxicity control using 20 mg/L test item and 10 mg/L reference compound were performed. The test item proved to be readily biodegradable and fulfilling the 10-d window criterion. The functional control reached the pass level > 60 % after 14 d. In the toxicity control containing both test and reference item 39 % biodegradation based on ThCO2 occurred within 14 d thus indicating that the test item was not inhibitory at the concentration tested.

In this test the test material attained 78 % degradation after 28 days and therefore can be considered as readily biodegradable. The test item proved to be readily biodegradable and fulfilling the 10-d window criterion. The validity criteria were fulfilled.

 

Moreover, the ready biodegradation of partially unsaturated TEA-Esterquat was also investigated according to OECD 301 D (1992) over a period of 28 days and using domestic sewage as inoculum. The biodegradation rate was determined by measurement of oxygen consumption. The test item proved to be readily biodegradable and fulfilling the 10-d window criterion. The functional control reached the pass level > 60 % after 14 d. In the toxicity control containing both test and reference item > 25 % biodegradation based on oxygen consumption occurred within 14 d thus indicating that the test item was not inhibitory at the concentration tested (Evonik Goldschmidt, 2005). The biodegradation was determined to be 66.2 %

 

Supplementary the TEA-Esterquat partially unsaturated proved to be readily biodegradable in a study (Clariant, 2005) according to OECD 301 B (1992). The test substance proved to be readily biodegradable (75 % biodegradation on average after 28 d.

 

Furthermore, the TEA-Esterquat partially unsaturated proved to be readily biodegradable in further studies according to OECD 301 B (1992). Biodegradation from 98.9 % to 71 % was observed (Elementis, 2005a, & Elementis, 2005b).

 

Anaerobic biodegradation

Under anaerobic conditions partially unsaturated TEA-Esterquat was biodegraded in a test according to ECETOC Anaerobic Biodegradation (Technical Report No. 28, 1988) with activated sludge from a sewage treatment plant as inoculum. The test material attained 76 % degradation after 56 days and therefore can be considered as biodegradable under anaerobic conditions (Kao, 1991).