Pidolic acid

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:

08 November to 09 December 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and batch No.of test material: 20140124
- Expiration date of the lot/batch: No data
- Purity test date: No data

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Ambient temperature
- Stability under test conditions: No data

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Collected from aeration tank 2 of 'STEP de Lille", 33290 Blanquefort, France water treatment plant
- Preparation of inoculum for exposure: Filtered through 1mm sieve to remove coarse particles, sludge washed by decanting in mineral medium until sludge was considered free from excess subtrate or inhibitor
- Pretreatment: Pre-conditioning consisted of aerating sludge in mineral medium for 5-7 days at test temperature
- Concentration of sludge: 3.65 g/L suspended solid
- Initial cell/biomass concentration:
- Water filtered: No

Duration of test (contact time):

>= 28 d

Initial conc.:

>= 100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: As described in guideline, medium was prepared from concentrated stock in ultrapure water (Na2HPO4.2H2O 334 mg/L, K2HPO4 217.5 mg/L, KH2PO4 85 mg/L, NH4Cl 5 mg/L, CaCl2.2H2O 36.4 mg/L, MgSO4.7H2O 22.5 mg/L, FeCl3.6H2O 0.25 mg/L)
- Test temperature: 20-24oC (actual range 21.9 - 22.4oC)
- pH: Day 0 6.4 - 7.6; Day 28 6.3 - 7.3
- pH adjusted: yes/no
- CEC (meq/100 g):
- Aeration of dilution water:
- Suspended solids concentration: final concentration approximately 30 mg/L
- Continuous darkness: Yes
- Other:

TEST SYSTEM
- Culturing apparatus:
- Number of culture flasks/concentration:
- Method used to create aerobic conditions:
- Method used to create anaerobic conditions:
- Measuring equipment:
- Test performed in closed vessels due to significant volatility of test substance:
- Test performed in open system:
- Details of trap for CO2 and volatile organics if used:
- Other:

SAMPLING
- Sampling frequency:
- Sampling method:
- Sterility check if applicable:
- Sample storage before analysis:
- Other:

CONTROL AND BLANK SYSTEM
- Inoculum blank:
- Abiotic sterile control:
- Toxicity control:
- Other:

STATISTICAL METHODS:

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

>= 100.7

Sampling time:

7 d

Remarks on result:

other: ThOD NH4 (1.115 mg O2/mg/test substance)

Parameter:

% degradation (O2 consumption)

Value:

>= 69.7

Sampling time:

7 d

Remarks on result:

other: ThOD NO3 (1.611 mg O2/mg test substance)

Parameter:

% degradation (O2 consumption)

Value:

>= 112.4

Sampling time:

14 d

Remarks on result:

other: ThOD NH4 (1.115 mg O2/mg test substance)

Parameter:

% degradation (O2 consumption)

Value:

>= 77.8

Sampling time:

14 d

Remarks on result:

other: ThOD NO3 (1.611 mgO2/mg test substance)

Parameter:

% degradation (O2 consumption)

Value:

>= 114.1

Sampling time:

21 d

Remarks on result:

other: ThOD NH4 (1.115 mg O2/mg test substance)

Parameter:

% degradation (O2 consumption)

Value:

>= 79

Sampling time:

21 d

Remarks on result:

other: ThOD NO3 (1.611 mgO2/mg test substance)

Key result

Parameter:

% degradation (O2 consumption)

Value:

>= 114

Sampling time:

28 d

Remarks on result:

other: ThOD NH4 (1.115 mg O2/mg test substance)

Key result

Parameter:

% degradation (O2 consumption)

Value:

>= 78.9

Sampling time:

28 d

Remarks on result:

other: ThOD NO3 (1.611 mgO2/mg test substance)

Details on results:

Start of 10-day window was Day 2, and at the end of the 10-day window the degradation was 71.2% (Day 5, ThOD NH4) and 60.9% (Day 6, ThOD NO3)

Results with reference substance:

The positive control showed 80.8% degradation after 14 days and 79.3% degradation after 28 days
The toxicity control showed 104.5% degradation after 14 days and 105.1% degradation after 28 days

Day	% degradation
	Test substance^1	Test substance^2	Positive control	Toxicity control	Abiotic control
7	100.7	69.7	73.3	95.8	-
14	112.4	77.8	80.8	104.5	-
21	114.1	79.0	80.6	105.1	-
28	114.0	78.9	79.3	105.1	0

1             ThOD  _NH4= 1.115 mgO₂/mg test substance

2               ThOD  _NO3= 1.611 mgO₂/mg test substance

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test substance was readily biodegradable under the conditions of the test

Executive summary:

A study was performed to assess the ready biodegradability of the test substance according to OECD test guideline OECD 301F (Determination of ready biodegradability - manometric respiration test), in compliance with GLP.

The test substance, at nominal 100 mg/L in mineral medium, was inoculated with effluent from a treatment works treating predominantly domestic sewage and incubated for 28 days. During this period the biodegradation was followed by O2 consumption, based on the ThOD of the test substance. The ThOD defined as the total amount of oxygen required to oxidise the test substance completely; and was calculated assuming no nitrification occurs (ThOD NH4) and assuming nitrification occurs (ThOD NO3).

The test substance showed 100.7, 112.4, 114.1 and 114.0% degradation after 7, 14, 21 and 28 days (assuming no nitrification occurs) and 68.7, 77.8, 79.0 and 78.9% degradation after 7, 14, 21 and 28 days (assuming nitrification occurs).

The positive control showed 80.8% degradation after 14 days and 79.3% degradation after 28 days.

The toxicity control showed 104.5% degradation after 14 days and 105.1% degradation after 28 days.

The test substance is considered to be readily biodegradable under the conditions of the test and is not considered to have an inhibitory effect on sewage treatment process microorganisms at the nominal test concentration of 100 mg/L.

The study is considered acceptable and satisfies the guideline requirements for a biodegradation in water screening test.

Description of key information

A reliable study was performed to assess the ready biodegradability of the test substance according to the test guideline OECD 301F (Determination of ready biodegradability - manometric respiration test), in compliance with GLP.

The test substance was incubated with mineral medium and effluent from a treatment works treating predominantly domestic sewage for 28 days. Biodegradation was based on O2 consumption and the ThOD of the test substance. The ThOD, defined as the total amount of oxygen required to oxidise the test substance completely; was calculated assuming no nitrification occurs (ThOD NH4) and nitrification occurs (ThOD NO3).

The test substance showed 114% degradation after 28 days (assuming no nitrification occurs) and 79% degradation after 28 days (assuming nitrification occurs).

The test substance is considered to be readily biodegradable and meets the 10 -day window criterion under the conditions of the test.

The study is considered acceptable and satisfies the guideline requirements for a biodegradation in water screening test.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable