4-bromo-2,2-diphenylbutyric acid

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:

2016-11-07 to 2016-11-29

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

less than 25% biodegradation (based on ThCO2 of the test and positive control items combined) occurred within 14 days in the toxicity control

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

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:

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

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: ISO International Standard 9439 “Water Quality - Evaluation of ultimate aerobic biodegradability of organic compounds in aqueous medium - carbon dioxide evolution test (1999).

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: ISO International Standard 10634 "Water Quality - Guidance for the preparation and treatment of poorly water-soluble organic compounds for the subsequent evaluation of their biodegradability in an aqueous medium" (1995)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

4-bromo-2,2-diphenylbutyric acid

EC Number:

253-648-3

EC Name:

4-bromo-2,2-diphenylbutyric acid

Cas Number:

37742-98-6

Molecular formula:

C16H15BrO2

IUPAC Name:

4-bromo-2,2-diphenylbutanoic acid

Test material form:

solid: particulate/powder

Details on test material:

- Name of test material (as cited in study report): JNJ-1580774-AAA (T000835)
- Physical state: solid powder
- Appearance: slight beige

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: I16BB1136
- Expiration date of the lot/batch: 02 March 2017
- Purity: 99.3% (based on acid titration assay)
- Purity test date: 2016-04-27

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature
- Stability under test conditions: not indicated
- Solubility and stability of the test substance in the solvent/vehicle: 0.04 g/L in water

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum: Municipal sewage treatment plant: 'Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands
- Storage conditions: sludge was kept under continuous aeration for 26 hours until further treatment
- Preparation of inoculum for exposure: Before use, the sludge was allowed to settle (61 minutes) and the supernatant liquid was used as inoculum.
- Pretreatment: no
- Concentration of sludge: the concentration of suspended solids was determined to be 4.1 g/L in the concentrated sludge.
- Water filtered: tap-water pruified by reverse osmosis (Milli-RO) and subsequently passed over activated carbon

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

20 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

12 mg/L

Based on:

TOC

Details on study design:

TEST CONDITIONS
- Composition of medium: test water prepared according to test guidelines, analytical grade salts dissolved in tap-water purified by reverse osmosis (Milli-RO) and subsequently passed over activated carbon.
* mineral stock solution A: 8.5 g KH2PO4, 21.75 g K2HPO4, 67.20 g Na2HPO4.12H2O, 0.5 gNH4Cl dissolved in 1 L Milli-Q water, pH 7.4 ± 0.2
* mineral stock solution B: 22.50 g MgSO4.7H2O dissolved in 1 L Milli-Q water
* mineral stock solution C: 36.4 g CaCl2.2H2O dissolved in 1 L Milli-Q water
* mineral stock solution D: 0.25 g FeCl3.6H2O dissolved in 1 L Milli-Q water
* Final test medium: 10 mL of solution A and 1 mL of solutions B, C and D per L of test medium
- Additional substrate: no
- Test temperature: 21.9-23.5°C
- pH: 7.5-8.0, measured prior to testing in each test flask before addition of inoculum, and again in each test flask at the end of the incubation period
- pH adjusted: yes, at the start of the test to pH 7.6, using 1 M HCl.
- Aeration of dilution water: The test solutions were continuously aerated and stirred during the test.
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 2-L all-glass brown coloured bottles
- Number of culture flasks/concentration: 2
* test substance and inoculum: 2 replicates
* inoculum blank: 2 replicates
* positive control: 1 replicate
* toxicity control: 1 replicate
- Method used to create aerobic conditions: A mixture of oxygen (~20%) and nitrogen (~80%) was passed through a bottle, containing 0.5 - 1 L 0.0125 M Ba(OH)2 solution to trap CO2. The synthetic air was sparged through the scrubbing solutions at a rate of ~1-2 bubbles per second ( ~30-100 mL/min). The initial suspension of unspiked test medium and inoculum was aerated with this CO2-free air overnight to purge the system of CO2 prior to testing. This CO2-free air was also used for aeration during the test.
- Measuring equipment: CO2-evolution was determined through titration of the remaining Ba(OH)2 with 0.05 M standardized HCl.
- Details of trap for CO2 and volatile organics if used: Three CO2-absorbers (bottles filled with 100 mL 0.0125 M Ba(OH)2 were connected in series to the exit air line of each test bottle.

SAMPLING
- Sampling frequency: every second or third day during the first 10 days, and thereafter at least every fifth day until the 28th day
- Sampling method: the absorber bottle closest to the incubation system was sampled each time, the second and third bottle were moved one position closer to the system and a new bottle was added at the end
- On the 28th day, pH of test suspensions was measured and 1 mL of concentrated HCl was added to each bottle. Bottles were aerated overnight to drive off CO2 present in the test suspension. The final titration was made on day 29.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, two replicates with only inoculum
- Toxicity control: yes, one replicate with test item, reference substance, and inoculum
- Procedure control: yes, 1 replicate with reference item and inoculum

Reference substance

Reference substance:

acetic acid, sodium salt

Results and discussion

Test performance:

-In the toxicity control, less than 25% biodegradation occurred within 14 days (13%, based on ThCO2). Therefore, the test item was assumed to inhibit microbial activity at a target concentration of 20 mg/L, corresponding to 12 mg TOC/L.
-The positive control substance was degraded at least 60 % (75%) within 14 days.

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

23.5

Sampling time:

28 d

Remarks on result:

other: average of the two test bottles

Details on results:

-The criterion for ready biodegradability (at least 60% biodegradation within a 10-days window) was not met.

BOD5 / COD results

Results with reference substance:

-The positive control item was biodegraded by at least 60% (75%) within 14 days, confirming suitability of the activated sludge.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

A 28-d ready biodegradability test (OECD 301B, modified Sturm test) using unadapted activated sludge from a predominantly domestic waste water treatment plant indicated that JNJ-1580774-AAA (T000835) was not readily biodegradable under the conditions of the test (initial concentration 20 mg/L).
The test substance showed 17 % and 30% biodegradation (test bottle A and B, respectively, based on % ThCO2).
In the toxicity control, JNJ-1580774-AAA (T000835) was found to have an inhibiting effect on microbial activity at the tested target concentration of 20 mg/L, corresponding to 12 mg TOC/L. The inhibition of microbial activity did not have a significant impact on the classification of the test item.