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Environmental fate & pathways

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:
2017-05-10 to 2017-06-09
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 guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
ISO DIS 9439 (Ultimate Aerobic Biodegradability - Method by Analysis of Released Carbon Dioxide)
Deviations:
no
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"
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
1-((2-chlorophenyl)-N-methylcarbonimidoyl)cyclopentan-1-ol
EC Number:
641-894-8
Cas Number:
6740-87-0
Molecular formula:
C13H16ClNO
IUPAC Name:
1-((2-chlorophenyl)-N-methylcarbonimidoyl)cyclopentan-1-ol
Test material form:
solid
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Analytical purity: 99.5% (based on assay UPLC)
- Source and lot/batch No.of test material: I17BB0589
- Expiration date of the lot/batch: 12 February 2018 (retest date)

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: In refrigerator (2-8°C) in container flushed with argon
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle: solubility in water: not available

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: The freshly obtained sludge was used immediately
- Preparation of inoculum for exposure: Before use, the sludge was allowed to settle (37 minutes) and the supernatant liquid was used as inoculum.
- Pretreatment: no
- Concentration of sludge: the concentration of suspended solids was determined to be 3.9 g/L in the concentrated sludge.
- Water filtered: tap-water purified by reverse osmosis (Milli-RO) and subsequently passed over activated carbon
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
18.5 mg/L
Based on:
test mat.
Initial conc.:
12 mg/L
Based on:
other: TOC
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
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 g NH4Cl 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: 22.2-23.3°C
- pH: 7.4-7.6, 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: pH at the start of the test was adjusted from pH 7.8 to pH 7.6 using 1 M HCl (Merck, Darmstadt, Germany)
- 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: Titration were made every second or third day during the first 10 days, and thereafter at least every fifth day until the 28th day, for the inoculum blank and test item. Titration for the positive and toxicity control were made over a period of at least 14 days.
- 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 penultimate day, pH of test media was measured and 1 mL of concentrated HCl was added to test 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% degradation occurred within 14 days (41% based on ThCO2). Therefore, the test item was assumed not to inhibit microbial activity.
The positive control substance was degraded at least 60% (84%) within 14 days.
% Degradation
Key result
Parameter:
% degradation (CO2 evolution)
Value:
ca. 18
Sampling time:
28 d
Remarks on result:
other: mean of test bottle A and B
Details on results:
The criterion for ready biodegradability (at least 60% biodegradation within 10 days of biodegradation exceeding 10%) was not met.

BOD5 / COD results

Results with reference substance:
The positive control item was biodegraded by at least 60% (84%) 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-54433041-AAA (T003641) was not readily biodegradable under the conditions of the test (initial concentration 18.5 mg/L). The test substance showed only 19% and 17% biodegradation (test bottle A and B, respectively, based on % ThCO2). The test substance did not inhibit microbial activity at the concentration used in the test. The results of the test can be considered reliable without restriction.

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