Fatty acids, tall-oil, reaction products with linseed oil, maleic anhydride and methanol

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

02 July 2015 to 05 August 2015

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

The test substance is listed as ZWA 5496/100. The test substance, a brown liquid, is the reaction product of maleic anhydride, disproportioned tall oil fatty acid, linseed oil and methanol. The test substance was obtained from Allnex Belgium and was stored at room temperature (20 ± 5°C) and kept away from light.

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Activated sludge from a biologic sewage treatment plant treating mostly domestic sewage was used in the study. The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf on 03 July 2015.

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

TOC

Initial conc.:

29 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Reference substance:

aniline

Key result

Parameter:

% degradation (CO2 evolution)

Value:

32

Sampling time:

10 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

41

Sampling time:

28 d

Validity criteria fulfilled:

yes

Remarks:

IC content 0.59% (protocol ≤ 5%); CO2 emitted by controls 11 mg/L (protocol <70 mg/L; difference in replicates 1.1% (protocol ≤20 %); degradation positive control >60% at 11 d (protocol ≤14 d); degradation toxicity flask d 14, 57% (protocol > 25%)

Interpretation of results:

inherently biodegradable

Conclusions:

Based upon test results (41% degradation in 28 days), the substance was reported as “not readily biodegradable”, below the passing criterion of 60% for ready biodegradability. The degradation rate of 41% in 28 days is evidence of inherent, primary biodegradability (> 20% biodegradation) and significant mineralisation (> 40% degradation). Therefore, the test substance was reported as "very likely inherently biodegradable".

Abiotic degradation was not observed. The test substance was not inhibitory towards the inoculum; degradation of the reference substance was reported at 57% in the toxicity control after 14 days (above the criterion of 25% in 14 days, below which a substance is considered to be inhibitory).

Description of key information

The key study was a CO₂ evolution test conducted in accordance with OECD Guideline 301B. Based upon test results (41% degradation in 28 days), the substance was reported as “not readily biodegradable”, below the passing criterion of 60% for ready biodegradability. The degradation rate of 41% in 28 days is evidence of inherent, primary biodegradability (> 20% biodegradation) and significant mineralisation (> 40% degradation). Therefore, the test substance was also reported as "very likely inherently biodegradable".

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable