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

Biodegradation in soil

Administrative data

Endpoint:

biodegradation in soil: simulation testing

Type of information:

other: Literature weight of evidence

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Biodegradation of mono-alkyl phthalate esters in natural sediments.

Author:

Otton, V., Sura, S., Blair, J., Ikonomou, M. and Gobas, F.

Year:

2008

Bibliographic source:

Chemosphere 71 (11): 2011-2016

Reference 2

Reference Type:

publication

Title:

Measurement of Sorption Coefficients of Organic Chemicals and Their Use in Environmental Fate Analysis, Test Protocols for Environmental Fate and Movement of Toxicants, proceedings 94th Annual Meeting

Author:

McCall, P.J., Laskowski, D.A., Swann, R.L. and Dishburger, H.J.

Year:

1980

Bibliographic source:

94th Annual Meeting, Association of Official Analytical Chemists, Washington, D.C., October 21-22, 1980, pp. 89-109.

Report date:

1980

Reference 3

Reference Type:

publication

Title:

High Production Volume (HPV) Chemical Challenge Program Test Plan for the Trimellitate Category

Author:

Exxon Biomedical Sciences.

Year:

2001

Bibliographic source:

Submitted to the US EPA on 13 Dec. 2001.

Report date:

2001

Reference 4

Reference Type:

publication

Title:

Guidance on information requirements and chemical safety assessment Chapter R.7C: endpoint specific guidance

Author:

European Chemicals Agency

Year:

2008

Bibliographic source:

http://reach.jrc.it/docs/guidance_document/information_requirements_r7c_en.pdf?vers=30_07_08

Materials and methods

Principles of method if other than guideline:

Weight of evidence from literature

GLP compliance:

no

Test type:

not specified

Test material

Test material information

1

Reference substance name:

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

EC Number:

290-754-9

EC Name:

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

Cas Number:

90218-76-1

Molecular formula:

C33H51O6 to C39H66O6

IUPAC Name:

tris(mixed decyl and octyl)benzene-1,2,4-tricarboxylate

Test material form:

liquid

Remarks:

Colorless

Details on test material:

Product name : LINPLAST 810 TM unstabilized (P0810TU)
Batch number: 05804/MA
Relative density at 20 °C: 0.972*
Water Solubility: < 28.3 µg/L
Expiry date: 2023-01-31

The test item and the information concerning the test item were provided by the sponsor.
* information was provided by the ECHA

Results and discussion

Half-life / dissipation time of parent compound

Remarks on result:

not measured/tested

Remarks:

WoE

Transformation products:

not measured

Applicant's summary and conclusion

Conclusions:

The data requirement for soil biodegradation is waived based on the weight of evidence supporting the conclusion that, while pathways exist for the degradation of 1,2,4-Benzenetricarboxylic acid, mixed decyl and octyl triesters, the degradation of substance will be limited due to limited bioavailability.  

Executive summary:

There are no data for soil biodegradation simulation studies relating to 1,2,4-Benzenetricarboxylic acid, mixed decyl and octyl triesters. Soil biodegradation simulation studies are not needed due to the fact that microbial pathways exist for the degradation of 1,2,4-Benzenetricarboxylic acid, mixed decyl and octyl trimesters and that significant biodegradation has been demonstrated even though the physico-chemical properties of the substance predict that degradation in standard guideline studies could be limited due to limited bioavailability. Poor bioavailability limiting the degradation rate of a substance has been noted in ECHA documentation (ECHA, 2017). Biodegradation Pathway and Rate A microbial pathway (ester hydrolysis) does exist in nature for degradation of esters (Otton et al., 2008). According to the trimellitate category test plan for the US EPAs HPV Chemical Challenge Program, the degradation of the trimellitates is expected to proceed through the step-wise hydrolysis of the ester groups to free alcohols and trimellitic acid (ExxonMobil Biomedical Sciences, 2001). Further, the test plan states that these metabolites are known to rapidly degrade and not persist. Evidence of the true biodegradation potential for 1,2,4-Benzenetricarboxylic acid, mixed decyl and octyl triesters can be observed with the results from two OECD 301B ready biodegradability studies. In both studies there is an extended time lag (14 to 24 days) before biodegradation begins to occur. However, once biodegradation is initiated, the substance is significantly degraded (>70%) within 48 days with >60% degradation occurring at 35 and 43 days in the studies. The slow but steady increase in degradation observed in the studies indicate that the microorganisms required time for accessing and degrading the substance (ECHA, 2017). Limited Bioavailablity 1,2,4-Benzenetricarboxylic acid, mixed decyl and octyl triesters is an extremely hydrophobic substance that may have limited bioavailability to microorganisms living in soil. The measured log Koc value was greater than 5.67 (the log Koc of the most hydrophobic standard). Using the KOCWIN Program v2.00 embedded in the US EPAs EPI Suite software (EPIWEB 4.0), the calculated log Koc values for 1,2,4-Benzenetricarboxylic acid, mixed decyl and octyl triesters ranged from 7.87 (estimated from the log Pow) to 8.46 (estimated from MCI). The equivalent calculated Koc values were 74,000 L/kg to 290,000 L/kg. Based on these results, 1,2,4-Benzenetricarboxylic acid, mixed decyl and octyl triesters is expected to be immobile in soil (Koc >5000, classification according to McCall et al., 1980). No Toxicity to Soil Organisms In toxicity studies with soil organisms (earthworms and terrestrial plants), no toxicity was observed with the highest concentrations tested (1000 mg/kg – earthworms and 100 mg/kg – terrestrial plants). Conclusion The data requirement for soil biodegradation simulation testing is waived based on the weight of evidence supporting the conclusion that there are established pathways for the degradation of 1,2,4-Benzenetricarboxylic acid, mixed decyl and octyl triesters and the substance reached >60% degradation in two 301B studies after an extended lag period. In addition, the substance did not cause toxicity to soil organisms.