Tetraol

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-02-09 to 2015-03-10

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Deviations:

no

Test guideline 3

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)

Remarks:

BASF SE, Experimental Toxicology and Ecology, 67056 Ludwigshafen, Germany

Test material

Test material information

Constituent 1

Test material form:

solid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Lot/batch No.of test material: lot 003
- Expiration date of the lot/batch: January 2020

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Storage at room temperature; no direct sunlight; hygroscopic
- Storage stability: The stability under storage conditions over the prospective exposure/administration period is guaranteed by the sponsor and the sponsor holds this responsibility.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Municipal waste water treatment plant Mannheim, Germany. The inoculum was collected on 09 February 2015 from the aeration tank of the plant.
- Preparation of inoculum for exposure: A suitable aliquot of the activated sludge suspension was sieved by a finely woven mesh with a mesh size about 1 mm. To reduce the content of inorganic carbon in the blank controls the activated sludge was aerated with carbon dioxide free air for about 24 hours at 22 ± 2 °C. At the day of exposure the suspension was washed one time with drinking water. Subsequently the aeration was stopped and the sludge was allowed to settle. After settling the supernatant was discarded and the remaining sludge suspension was filled up with drinking water.
- Concentration of sludge: 30 mg/L dry weight
- Water filtered: yes
- Type and size of filter used, if any: 1mm

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

10 mg/L

Based on:

TOC

Initial test substance concentration 2

Initial conc.:

15 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: according to guideline
- Test temperature: 22 ± 2 °C
- pH: 7.4 ± 0.2
- pH adjusted: yes
- Aeration of dilution water: Yes. At begin of the exposure phase the test vessels were connected with an aeration unit and the bubble aeration with carbon dioxide free air was started after connecting the several test vessels with the absorption units. The test assays were stirred using magnetic stirrers.

TEST SYSTEM
- Culturing apparatus: The test was performed in 2 L incubation bottles filled up to a volume of 1.5 L.
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: Aeration with carbon dioxide free air
- Measuring equipment: The TIC- and DOC-analyses were performed as repeat determination, using a TOC-analyzer equipped with an auto sampler (Shimadzu TOC-5000A and/or TOC-L CSH/CSN).
- Details of trap for CO2 and volatile organics if used: The bottles were connected to two serial scrubbing bottles (total volume 250 mL) filled with 100 mL 0.05 mol sodium hydroxide solution for the adsorption of carbon dioxide from biodegradation processes. Usually twice a week the Total Inorganic Carbon (TIC) values of the adsorption solutions of the first trap were determined and used for the calculation of the produced carbon dioxide. After each sampling the second trap was moved forward and the new trap with fresh sodium hydroxide solution was placed into the second position. Each trap was analyzed separately.

SAMPLING
- Sampling frequency and method: Usually twice a week the Total Inorganic Carbon (TIC) values of the adsorption solutions of the first trap were determined and used for the calculation of the produced carbon dioxide. After each sampling the second trap was moved forward and the new trap with fresh sodium hydroxide solution was placed into the second position. Each trap was analyzed separately.

CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes (2)
- Inhibition control: Yes (1)

Reference substance

Reference substance:

aniline

Results and discussion

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

> 30 - < 40

Sampling time:

28 d

BOD5 / COD results

Results with reference substance:

The biodegradation in the reference test was >60% after 14 days.

Any other information on results incl. tables

Validity criteria:

Measured DIC-concentrations in the blank controls at begin of exposure (mean value): 0.9 mg/L

Amount of produced CO2 in the blank controls at the end of exposure (mean value): 44.9 mg/L

Deviation of the degree of biodegradation of the test substance in the plateau phase should be 20%: Yes

The degree of biodegradation of the reference substance should be >60% CO2/ThCO2 after 14 days: Yes

The degree of biodegradation in the inhibition control should be>25 % CO2/ThCO2 after 14 days: Yes

The content of DIC in the blank control at start of exposure at the test concentration of 20 mg/L TOC should be <1 mg/L: *No

The amount of produced CO2 in the inoculum blank (“blank controls”) at the end of exposure (mean value) should be <70 mg/L: Yes

*Remark: The required validity criterion was slightly failed. An influence to the test result may be excluded.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

One validity criterion was slightly failed. An influence to the test result may be excluded.

Interpretation of results:

not readily biodegradable

Conclusions:

The test substance was not readily biodegradable under the conditions of this test. The required pass level for ready biodegradability within a ten days window was not reached.

Executive summary:

A CO2-evolution test according to OECD guideline 301B was performed in order to evaluate aerobic elimination and degradation potential of the test substance. An initial test concentration of 10 mg/L TOC nominal (corresponding to 15 mg/L test substance) was applied. After an exposure period of 28 days the determined degree of biodegradation was 30 -40% in this test. Therefore, the test substance was regarded as readily biodegradable under the conditions off this test. The required pass level for ready biodegradability within a ten days window was not reached.