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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:
15 December 2016 - 12 January 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 guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
ISO 14593:1999 (Water quality - Evaluation of ultimate aerobic biodegradability of organic compounds in aqueous medium - Method by analysis of inorganic carbon in sealed vessels (CO2 headspace test))
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
2-bromobutane
EC Number:
201-140-7
EC Name:
2-bromobutane
Cas Number:
78-76-2
Molecular formula:
C4H9Br
IUPAC Name:
2-bromobutane
Test material form:
liquid
Details on test material:
- Name of test material (as cited in the report): JNJ-47961173-AAA
- Physical state: Liquid
- Colour: Colourless
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: M15IB3251
- Expiration date of the lot/batch:07 April 2017 (retest date)
- Purity: 100% (based on gas chromatographic purity)

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature
- Stability under test conditions: stable

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 (30 minutes) and the supernatant liquid was used as inoculum.
- Pretreatment: no
- Concentration of sludge: the concentration of suspended solids was determined to be 5 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):
ca. 28 d
Initial test substance concentrationopen allclose all
Initial conc.:
57 mg/L
Based on:
test mat.
Initial conc.:
20 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: 20-22°C
- pH: 7.3-7.7, measured prior to testing.
- pH adjusted: no
- Aeration of dilution water: The test was performed in sealed bottles with a headspace of air.
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: Sealed glass serum bottles with capacity of 160 mL
- Number of culture flasks/concentration: 2
* test substance and inoculum: 5 replicates
* inoculum blank: 5 replicates
* positive control: 3 replicates
* toxicity control: 3 replicates
- Abiotic control: containing untreated medium, test item and sterilising agent
- Measuring equipment: Each sample was analysed in triplicates using Shimadzu TOC-VCPH total organic carbon analyzer combined with a Shimadzu ASI-V autosampler.

SAMPLING
- Sampling frequency: all the solutions were sampled on day 1, 7 and 14. Inoculum blank and test item additionally on day 21 and 28.
- Sampling method: 7 M NaOH was injected into each bottle, after which they were shaken for 1 h. The bottles were removed from the shaker and allowed to settle and the supernatant was used for IC analysis.

CONTROL AND BLANK SYSTEM
The test consisted of five groups:
- Inoculum blank: containing inoculated medium.
- Procedure control: containing inoculated medium and reference item.
- Test item: containing inoculated medium and test item.
- Toxicity control: containing inoculated medium, reference item and test item.
- Abiotic control: containing untreated medium, test item and sterilising agent
Reference substance
Reference substance:
other: 1-Octanol

Results and discussion

Preliminary study:
-The mean amount of TIC present in the blank controls at the end of the test was < 3 mg C/L (1.8 mg C/L).

Test performance:
The mean percentage degradation of the reference item has reached the level for ready biodegradability (>60%) by 14 days (83%). The mean amount of TIC present in the blank controls at the end of the test was < 3 mg C/L (1.8 mg C/L). Since all criteria for validity of the test were met, this study was considered to be valid.

Between 24-Dec-2016 and 27-Dec-2016 the temperature has periodically been above the range as stated in the study plan (20±1°C). Evaluation: The temperature has only been above the specified range momentarily, and never for longer than 15 minutes. Since all validity criteria were met, it can be stated that this deviation has had no significant impact on this study.
% Degradation
Key result
Parameter:
% degradation (inorg. C analysis)
Value:
19
Sampling time:
28 d
Remarks on result:
other: relative biodegradation values calculated from the IC measurements
Details on results:
-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 reference item has reached the level for ready biodegradability (>60%) by 14 days (83%) confirming the suitability of the medium and test conditions.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
The relative biodegradation values calculated from the IC measurements performed during the test period revealed 19% biodegradation of JNJ-47961173-AAA (2-bromobutane). Thus, the criterion for ready biodegradability (at least 60% biodegradation within a 10-day window) was not met. Based on the results of the test, it can be concluded that JNJ-47961173-AAA (2-bromobutane) was not readily biodegradable. The results of the test can be considered reliable without restriction.