Methyl (R)-2-(4-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy)propionate

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.6 (Degradation: Chemical Oxygen Demand)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

XRD 535 Me
Lot # : GHD-2413-21
Purity: 93.9%

Oxygen conditions:

aerobic

Inoculum or test system:

other: Activated sludge bacteria

Details on inoculum:

- Source of inoculum/activated sludge: The aeration stage of the HRC Limited sewage treatment plant treating predominantly domestic sewage
- Preparation of inoculum for exposure: The sample was allowed to settle and the supernatant filtered through Whatman GFA filter paper (first 250 mL discarded)

Duration of test (contact time):

28 d

Initial conc.:

3 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: Standard nutrient medium (solution 1: KH2PO4, K2HPO4, Na2HPO4.2H2O, NH4Cl; solution 2: MgSO4.7H2O; solution 3: CaCl2; Solution 4: FeCl3.6H2O)
- Test temperature: 20 ± 1°C
- Continuous darkness: Yes

TEST SYSTEM
- Culturing apparatus: 280 mL BOD bottles (darkened glass) with ground glass stoppers
- Number of culture flasks/concentration: 2
- Test performed in closed vessels due to significant volatility of test substance: Closed vessels

SAMPLING
- Sampling frequency: 0, 5, 15 or 28 days

CONTROL AND BLANK SYSTEM
- Inoculum blank: Inoculated dilution water; inoculated dilution water and filter paper
- Abiotic sterile control: Non-inoculated dilution water

Reference substance:

benzoic acid, sodium salt

Remarks:

3 mg/L

Reference substance:

aniline

Remarks:

2 mg/L

Test performance:

Oxygen depletions in the inoculated and non-inoculated control series were within the prescribed limits

Key result

Parameter:

% degradation (DOC removal)

Value:

>= 8 - <= 11

Sampling time:

28 d

Details on results:

Oxygen depletion (28 days): 0.375 mgO2/L

Parameter:

ThOD

Value:

4.47 other: mgO2/L

Results with reference substance:

Sodium benzoate attained 81-83% degradation within 28 days.
Aniline attained 59% degradation within 28 days.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Not readily biodegradable

Executive summary:

The ready biodegradability of the test substance was assessed using a closed bottle procedure according to EEC directive C6 and OECD guideline 301D.

The test substance attained between 8-11% degradation after 28 days and therefore cannot be termed as readily biodegradable.

The standard substances, sodium benzoate and aniline, attained 81-83% and 59% degradation respectively within 28 days.

Oxygen depletions in the inoculated and non-inoculated control series were within the prescribed limits.

Description of key information

Study Type	Study Details	Value	Guideline	Reliability
Ready Biodegradation Study	Closed bottle method	Not Readily Biodegradable	OECD 301D EU Method C.6	1

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable