Trimethylamine, N-oxide

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study, not GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

concentration of sludge 30mg/l

Duration of test (contact time):

14 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

aniline

Parameter:

% degradation (O2 consumption)

Value:

92

Sampling time:

14 d

Details on results:

Degree of biodegradation: 92% (NH3) by BOD; 66% (NO2) by BOD

Results with reference substance:

no data given.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

92 % degradation has occured within 14 days, based on O2 consumption for trimethylamine.

Reference 2

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 attached document in section 13 "Assessment reports" for rationale and justification of the analogy approach.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Value:

94

Sampling time:

14 d

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Based on the analogy approach between the two substances TMAO and TMA, they are expected to have the same behavior in environmental in aquatic compartment. Hence, the trimethylamine N-oxide was considered ready biodegradable as the source substance, the trimethylamine.

Executive summary:

Based on their physico-chemical properties, the two substances showed similarity on their structure except the oxygen in the TMAO. Both of the two substances are soluble in water. The Log Kow values for the two substances are lower than 0. The two substances could be found in environmental aqueous compartments due to their physico-chemical properties. Additionally, Henry’s law constant were calculated. The transfer from water to air compartments is considered to be slow, even negligible. QSAR were performed on TMAO (ready biodegradability and toxicity to fish, daphnia and algae). Similar results were found for target compared to experimental values obtained on the source substance : readily biodegradable (by Biowin and Vega), fish acute toxicity > 100 mg/L (Ecosar and Vega), daphnia acute toxicity: 10-100 mg/L (Ecosar and Vega), algae acute toxicity >100 mg/L (Ecosar), daphnia chronic toxicity: 1-10 mg/L (Ecosar), algae chronic toxicity: 10-100 mg/L (Ecosar).

Hence, the trimethylamine N-oxide was considered ready biodegradable as the source substance, the trimethylamine.

Description of key information

The source substance (N,N-dimethylmethanamine) was tested in OECD 301C method. Concentration of sludge was 30 mg/L and substance was tested at 100 mg/L. Biodegradation was followed by O2 consumption during 14 days. Biodegradation rate at 14D: 92% (NH3) by BOD; 66% (NO2) by BOD.

Based on their physico-chemical properties, the two substances showed similarity on their structure except the oxygen in the TMAO. Both of the two substances are soluble in water. The Log Kow values for the two substances are lower than 0. The two substances could be found in environmental aqueous compartments due to their physico-chemical properties. Additionally, Henry’s law constant were calculated. The transfer from water to air compartments is considered to be slow, even negligible. QSAR were performed on TMAO (ready biodegradability and toxicity to fish, daphnia and algae). Similar results were found for target compared to experimental values obtained on the source substance : readily biodegradable (by Biowin and Vega), fish acute toxicity > 100 mg/L (Ecosar and Vega), daphnia acute toxicity: 10-100 mg/L (Ecosar and Vega), algae acute toxicity >100 mg/L (Ecosar), daphnia chronic toxicity: 1-10 mg/L (Ecosar), algae chronic toxicity: 10-100 mg/L (Ecosar).

Hence, the trimethylamine N-oxide was considered ready biodegradable as the source substance, the trimethylamine.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater