Reaction mass of dodecyltrimethylammonium bromide and tetradonium bromide

Biodegradation in soil

Description of key information

Biodegradation in soil was examined for cetrimonium chloride. The biodegradability was measured by following the 14CO2 evolution from 14C-labelled substances added to the soil. The biodegradation in soil of cetrimonium chloride was approximately 60% in 58 days.
For this type of substances, the degradability is determined by the alkyl structure and not by the counter ion. Therefore the degradability of compounds of chloride is considered to be representative for the structurally alike bromide compounds. The biodegradability decreases with the length of the alkyl chain (according to studies by Garcia et al, 2001 and Yamane et al 2008), thus the biodegradability of reaction mass of C14 trimethylammonium bromide and C12 trimethylammonium bromide can be described by the biodegradability of the cetrimonium halides (C16)

Key value for chemical safety assessment

Half-life in soil:

58 d

at the temperature of:

22 °C

Additional information

Biodegradation in soil was examined for cetrimonium chloride. For this type of substances, the degradability is determined by the alkyl structure and not by the counter ion. Therefore the degradability of compounds of chloride is considered to be representative for the structurally alike bromide compounds. The biodegradability decreases with the length of the alkyl chain (according to studies by Garcia et al, 2001 and Yamane et al 2008), thus the biodegradability of the substance reaction mass of C12 trimethyl ammonium bromide and C14 trimethylammonium bromide can be described by the biodegradability of the cetrimonium halides (C16). The biodegradability was measured followed by the 14CO2 evolution from 14C-labelled substances added to the soil. The biodegradation in soil of cetrimonium chloride was approximately 60% in 58 days. Based on the results, cetrimonium chloride can be considered as biodegradable in soil and not persistent. The same can be concluded for reaction mass of C12 trimethyl ammonium bromide and C14 trimethylammonium bromide using the read across approach, thus it can be concluded that the half-life in soil for reaction mass of C12 trimethyl ammonium bromide and C14 trimethylammonium bromide is less than 58 days.

The biodegradability of cetrimonium bromide in soil was confirmed in a published study testing the biodegradation by soil microorganisms using a standard BOD technique. The aqueous test system used an aqueous suspension of silt loam as inoculum. The study showed that soil microorganisms in suspension are able to degrade cetrimonium bromide at concentrations up to 25 µg/ml test solution. However, the biodegradation seems to be completely inhibited at 100 µg/ml, which probably is due to the toxicity of cetrimonium bromide to the microorganisms.