1,2,4-Benzenetricarboxylic acid, mixed lauryl and octyl triesters

Biodegradation in water: screening tests

Description of key information

• Two key studies for 1,2,4-Benzenetricarboxylic acid, mixed dodecyl and octyl triesters are reported for biodegradation:

 

The study from Chen Xiaoqian (2015) reports that 1,2,4-Benzenetricarboxylic acid, mixed dodecyl and octyl triesters was not readily biodegradable under the present test conditions.

 

The study from Zhang Jingji (2015) report that 1,2,4-Benzenetricarboxylic acid, mixed dodecyl and octyl triesters was primarily biodegradable, but not ultimately biodegradable. Therefore, the test substance was inherently biodegradable according the OECD definition.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable, not fulfilling specific criteria

Type of water:

freshwater

Additional information

The study from Chen Xiaoqian (2015) was conducted according to the guidelines of "Ministry of environmental protection of the people's Republic of China. The Guidelines for the Testing of Chemicals-Degradation and Accumulation, 2013, OECD 301F Ready Biodegradability: Manometric Respirometry Test, 1992". Under specific experimental conditions, the ready biodegradability of 1,2,4 -Benzenetricarboxylic acid, mixed dodecyl and octyl triesters was determined in a 28 -day dissolved oxygen depletion test using activated sludge from a domestic waste water treatment plan. The tested concentration of test substance was 20.08 mg/L and 20.48 mg/L (i.e. 52.81 mg/L ThOD/L and 53.86 mg ThOD/L). The concentration of sludge inoculum in the test system was 30 mg/L, and the tested concentration of sodium benzoate used as reference substance was 100 mg/L (i.e. 167 mg ThOD/L). A toxicity control was also performed.

 

During the test, the temperature was rnaintained at 22.1-22.9°C.The mean total O2 uptake in the inoculum blanks at the end of  the test was less than 60 mg O2/L in 28 days meeting the guideline requirement. Biodegradation of the reference substance (sodium benzoate) reached the pass level of the ready biodegradation test (> 60% within 14 days). Biodegradation of the reference substance (sodium benzoate) reached an average of 85% by Day 14.The difference of extremes between replicate values of the removal of the test substance during the 28 d test period was less than 20%. The results of the toxicity control showed that the test substance met the criteria for not being inhibitorγ to the rnicrobial inoculum. Thus, the test is valid.

 

Results showed that under the experimental conditions, biodegradation of test substance attained an average of 36 % at Day 23 (10-d window) and 43 % at Day 28 and did not meet the10-d window criteria.

Therefore, the test substance cannot be considered to be readily biodegradable under the experimental conditions according to this test method.

 

The study from Zhang Jingji (2015) was conducted according to the guidelines of "Ministry of environmental protection of the people's Republic of China. The Guidelines for the Testing of Chemicals-Degradation and Accumulation, 2013, OECD 302C Inherent Biodegradability: Modified MITI Test II " and "OECD Guidelines for the Testing of Chemicals, 1981, 302C: Inherent Biodegradability: Modified MITI Test (II)". Under specific experimental conditions, the ready biodegradability of 1,2,4 -Benzenetricarboxylic acid, mixed dodecyl and octyl triesters was determined in a 28-day dissolved oxygen depletion test using activated sludge from a domestic waste water treatment plan. The tested concentrations of test substance were 30.00 mg/L, 30.04 mg/L and 30.16 mg/L (i.e. 78.90 mg ThOD/L, 79.01 mg/L ThOD/L and 79.32 mg ThOD/L). The concentration of sludge inoculum in the test system was 100 mg/L, and the tested concentration of sodium benzoate used as reference substance was 100 mg/L (i.e. 167 mg ThOD/L). A toxicity control was also performed. During the test, the temperature was rnaintained at 24.6 -25.5°C. The mean total O2 uptake in the inoculum blanks for procedure control at the end of the test (28 days) was 23.95 mg O2/L, which is less than 60 mg O2/L in 28 days meeting the guideline requirement. Biodegradation of the reference substance (sodium benzoate) reached the pass level of the biodegradation test (> 60% within 14 days). Biodegradation of the reference substance (sodium benzoate) reached an average of 71% by Day 14. The difference of extremes between replicate values of the removal of the test substance during the 28 d test period was less than 20%. The results of the toxicity control showed that the test substance met the criteria for not being inhibitorγ to the rnicrobial inoculum. Thus, the test is valid. Results showed that under the experimental conditions, biodegradation of test substance attained an average of 55 % at Day 28, indicating that the test substance had primary biodegradability, but no ultimate biodegradability. Therefore, the test substance can be considered to be inherently biodegradable according to the definition specified by the OECD guideline.