Registration Dossier

Diss Factsheets

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
See read-across record in section 13.
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Key result
Parameter:
% degradation (CO2 evolution)
Value:
82
Sampling time:
28 d
Remarks on result:
other:
Remarks:
Result from read-across source substance Cas No. 30798-32-4
Key result
Parameter:
% degradation (test mat. analysis)
Value:
ca. 100
Sampling time:
5 d
Remarks on result:
other: Primary biodegradation of 5.7 mg/l TEA in a test with 164 mg/l municipal activated sludge
Remarks:
Result from read-across source substance CAS No. 102-71-6
Parameter:
% degradation (test mat. analysis)
Value:
ca. 100
Sampling time:
1 d
Remarks on result:
other: Primary biodegradation of 0.6 mg/l TEA in a test with 164 mg/l municipal activated sludge
Remarks:
Result from read-across source substance CAS No. 102-71-6

Description of key information

The test substance is readily biodegradable (according to OECD criteria)

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Additional information

No substance-specific data on the biodegradability of the substance (CAS 29340-81-6) are available. However, according to Article 13 of legislation EC1907/2006, in case no appropriate animal studies are available for assessment, information should be generated whenever possible by means other than vertebrate animal tests, i. e. applying alternative methods such as in vitro tests, QSARs, grouping and read-across. CAS 29340-81-6 is an organic compound manufactured from triethanolamine (TEA, CAS 102-71-6) and citric acid (CAS 77-92-9) and dissociates into the respective TEA cation and citrate anion. Therefore it is considered to be acceptable to derive lacking information on toxicological properties of CAS 29340-81-6 by read-across from its starting materials.

For TEA, the biodegradation potential in water was determined in a CO2 evolution test (no guideline given) (West, 1996). In this study 0.6 and 5.7 mg/L test substance was inoculated with mixed liquor activated sludge (secondary effluent) for 6 days under aerobic conditions. After the 6-day incubation period the substance was biodegraded c.a. 100% as CO2 evolution for both concentrations. Based on these findings, it is concluded that the TEA is readily biodegradable.

For MIPA citrate, the biodegradation potential of the substance in water was determined in a screening study according to OECD TG 301B (CO-Evolution Test) and in compliance with GLP criteria (Charles River, 2017). In this study, 41.5 mg/L test item (corresponding to 12 mg TOC/L) was inoculated with activated sludge from predominantly domestic sewage for 28 days under aerobic conditions in the dark. During the incubation period degradation was followed by determining the carbon dioxide produced. In addition, biodegradation of the reference substance sodium acetate (positive control) and inhibitory effects (toxicity control) were determined. Biodegradation of the reference substance was 85% after 14 days. Biodegradation degree of the toxicity control was 80% after 14 days. After the 28-day incubation period 82% of the test substance was biodegraded. The pass level of 60% degradation was reached within 11 days after the start of the test. Further calculation with mean values of biodegradation indicate the 10-day window was met. Based on these findings, the test substance is classified as readily biodegradable.

Taken together, it can be concluded that both starting products are readily biodegradable. Therefore, the test substance CAS 29340-81-6 is assessed to be readily biodegradable.