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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:
2017-03-14 to 2017-04-13
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:
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
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 (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
1'-(phenylmethyl)-[1,4'-bipiperidine]-4'-carbonitrile
EC Number:
282-544-0
EC Name:
1'-(phenylmethyl)-[1,4'-bipiperidine]-4'-carbonitrile
Cas Number:
84254-97-7
Molecular formula:
C18H25N3
IUPAC Name:
1'-benzyl-[1,4'-bipiperidine]-4'-carbonitrile
Test material form:
solid: particulate/powder
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: I15IB3393
- Expiration date of the lot/batch: 2017-08-19 (retest date)
- Purity test date: 2017-06-22 (certificate of analysis release date)

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: not indicated

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 (31 minutes) and the supernatant liquid was used as inoculum.
- Pretreatment: no
- Concentration of sludge: the concentration of suspended solids was determined to be 4.4 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 concentrationopen allclose all
Initial conc.:
16 mg/L
Based on:
test mat.
Initial conc.:
12 mg/L
Based on:
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 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: 7.6-7.7, 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: no
- 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
- pH was measured at the start of the test (day 0) and on the penultimate day, before addition of concentrated HCl.

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% (50%) biodegradation occurred within 14 days.
- The positive control item was biodegraded by at least 60% (86%) within 14 days.
- The difference of duplicate values for %-degradation of the test item was always less than 20 (≤10%).
- The total CO2 release in the blank at the end of the test did not exceed 40 mg/L (42.2 mg CO2 per 2 litres of medium, corresponding to 21.1 mg CO2/L).
- The Inorganic Carbon content (IC) of the test item (suspension) in the mineral medium at the beginning of the test was less than 5% of the Total Carbon content (TC). Since the test medium was prepared in tap-water purified by reverse osmosis (Milli-RO water (Millipore Corp., Bedford, Mass., USA, carbon levels < 500 ppb)), IC was less than 5% of TC (mainly coming from the test item, 12 mg TOC/L).
% Degradation
Key result
Parameter:
% degradation (CO2 evolution)
Value:
28
Sampling time:
28 d
Remarks on result:
other: mean of bottles A and B
Details on results:
- The criterion for ready biodegradability (at least 60% biodegradation within 10 days immediately following the attainment of 10% biodegradation) was not met.

BOD5 / COD results

Results with reference substance:
- The positive control item was biodegraded by at least 60% (86%) within 14 days confirming suitability of the activated sludge 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 indicated that the test item, JNJ-1594983-AAA (T000745) was significantly biodegraded under the conditions of the test (initial concentration 16 mg/L). The test substance showed 33% and 23% biodegradation (test bottle A and B, respectively, based on % ThCO2). However, since at least 60% biodegradation was not reached within 10 days immediately following the attainment of 10% biodegradation (10-day window), the criterion for ready biodegradability was not met. Thus, under the conditions of this test JNJ-1594983-AAA (T000745) was not readily biodegradable. The results of the test can be considered reliable without restrictions.

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