2H-1-Benzopyran, 6-fluoro-3,4-dihydro-2-[(2S)-2-oxiranyl]-, (2R)-

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:

21 February 2017 - 23 March 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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:

other: ISO International Standard 9439

Version / remarks:

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 3

Qualifier:

according to guideline

Guideline:

other: ISO International Standard 10634

Version / remarks:

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

Test material

Test material information

Constituent 1

Reference substance name:

(2R)-6-fluoro-2-[(2S)-oxiran-2-yl]-3,4-dihydro-2H-1-benzopyran

EC Number:

603-315-7

Cas Number:

129050-26-6

Molecular formula:

C11H11FO2

IUPAC Name:

(2R)-6-fluoro-2-[(2S)-oxiran-2-yl]-3,4-dihydro-2H-1-benzopyran

Test material form:

other: wax

Details on test material:

Physical state: wax form
Appearance: clear, viscous, wax

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: I16HB3199
- Expiration date of the lot/batch: 13 September 2017 (retest date)
Analytical purity: 86.6% (based on technical document DS-TEC-128833)

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature
- Stability under test conditions: not specified

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source: municipal sewage treatment plant receiving predominantly domestic sewage, 'Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands.
- Storage conditions: sludge was kept under continuous aeration until further treatment
- Preparation of inoculum for exposure: Before use, the sludge was allowed to settle (33 minutes) and the supernatant liquid was used as inoculum.
- Pretreatment: no
- Concentration of sludge: the concentration of suspended solids was determined to be 3.0 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.:

17.5 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: 22-24°C
- pH: 7.4-7.7, 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
- 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, more than 25% biodegradation occurred within 14 days (35%, based on ThCO2) at the tested target concentration of 17.5 mg/L, corresponding to 12 mg TOC/L. Therefore, the test substance was assumed to be not inhibitory on microbial activity.

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

3

Sampling time:

28 d

Remarks on result:

other: based on the mean of bottle A and B

Details on results:

The relative biodegradation values calculated from the measurements performed during the test period revealed no significant biodegradation (4% and 2%, based on ThCO2). Thus, the criterion for ready biodegradability (at least 60% biodegradation within a 10-day window) was not met.

BOD5 / COD results

Results with reference substance:

The positive control item was biodegraded by at least 60% (72%) within 14 days, confirming the suitability of the inoculum and the test conditions.

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 was performed with the test item JNJ-17337359-AAA (T001590). Based on the results of the test, it is concluded that the test item was not readily biodegradable, as the pass level for ready biodegradability, i.e. biodegradation of at least 60% in a 10-day window within the 28-day period of the test was not reached. The test substance showed only 4% and 2% biodegradation (test bottle A and B, respectively, based on % ThCO2). However, based on the results of the toxicity control, it is assumed that the test item did not inhibit microbial activity. The results of the test can be considered reliable without restriction.