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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2000-05-04 to 2000-06-02
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
GLP.
Qualifier:
according to guideline
Guideline:
EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)
Version / remarks:
adopted 31 July 1992
Deviations:
no
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Version / remarks:
adopted 17 July 1992
Deviations:
no
GLP compliance:
yes
Specific details on test material used for the study:
- Name of test material (as cited in study report): Benzyl methacrylate
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): water treatment plant Emeraude (SIARR) 76141 Petit-Quevilly, France; sampling date 26 April 2000
- Preparation of inoculum for exposure: initial sieving of sewage sludge, 5 min centrifugation, rejection of supernatant, redispersion of pellet in mineral medium
- Pretreatment: to wash out DOC, preconditioning for 6 days (air was bubbled through the inoculum during preconditioning), 22 ± 2°C
- Concentration of sludge: 12 mg/L (dry weight)
- Initial cell/biomass concentration: no data
- Water: reconstituted deionised water containing no more than 10% of the organic carbon introduced by addition of test substance / reference substance
Duration of test (contact time):
28 d
Initial conc.:
10 mg/L
Based on:
other: TOC
Initial conc.:
40 other: mg/flask (3 L)
Based on:
test mat.
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Composition of medium: according to OECD guideline 301
- Additional substrate: no
- Solubilising agent (type and concentration if used): none
- Test temperature: 20 - 23°C
- pH: at beginning of the test 7.58; day 28: 8.21 - 8.59
- pH adjusted: no
- Aeration of dilution water: flasks were bubbled with CO2-scrubbed air at 30 – 100 mL/min
- Suspended solids concentration: 12 mg/L
- Continuous darkness: yes (dark glass bottles fitted with dark glass stoppers)
- other: stirring with magnetic stirrer to homogenate the culture

TEST SYSTEM
- Culturing apparatus:
- Number of culture flasks/concentration: 2/ inoculum blank, 2/test substance, 1/reference substance
- Method used to create aerobic conditions: aeration (flasks were bubbled with CO2-scrubbed air at 30 – 100 mL/min)
- Details of trap for CO2: series of 3 wash bottles filled with 100 mL 0.0125 M barium hydroxide

SAMPLING
- Sampling frequency: days 1, 5, 8, 11, 14, 18, 21, 25, 29
- Sampling method: The CO2 produced by degradation was collected in a series of 3 wash bottles filled with 100 mL 0.0125 Ba(OH)2. The amount of CO2 was calculated by titration of the Ba(OH)2 solution with 0.05 M HCl, using phenolphthalein as indicator.
- Sterility check if applicable: no
- Sample storage before analysis: no data, probably immediate analysis

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes (2 flasks)
- Abiotic sterile control: no
- Toxicity control: no
- Other: reference substance (sodium acetate)
Reference substance:
acetic acid, sodium salt
Remarks:
10 mg TOC/L
Preliminary study:
n/a
Test performance:
n/a
Parameter:
% degradation (CO2 evolution)
Value:
74
Sampling time:
28 d
Parameter:
% degradation (CO2 evolution)
Value:
64
Sampling time:
12 d
Remarks on result:
other: end of 10 day window
Details on results:
The 10-day window started on day 2. Biodegradation totalled 64% at the end of the 10 day window (day 12) and 74% at the end of the test period.
Results with reference substance:
The reference substance degraded normally under the test conditions (68% after 14 days).
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The ready biodegradation of BNMA was investigated in a CO2 evolution test over a period of 28 days and using domestic sewage as inoculum. Inoculum blank and procedural/functional control with the reference substance sodium acetate were performed.
The 10-day window started on day 2. Biodegradation totalled 64% at the end of the 10 day window (day 12) and 74% at the end of the test period. The test item proved to be readily biodegradable and fulfilling the 10-d window criterion.

Executive summary:

The ready biodegradation of BNMA was investigated in a study conducted according to OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test) adopted 17 July 1992 and EU Method C.4-C, 31 July 1992, over a period of 28 days using sewage sludge sampled from the aeration tank of a predominantly domestic sewage treatment plant as inoculum. The biodegradation rate was determined by measurement of CO2 evolution. Inoculum blank and procedural/functional control with the reference substance sodium acetate were performed.

After 28 days the degradation of BNMA reached 74%.The functional control reached the pass level >60% after 14 d.

This study is regarded as reliable without restriction and satisfies the guideline requirements for ready biodegradation. BNMA proved to be readily biodegradable and fulfilling the 10-d window criterion.

NOTE: Any of data in this dataset are disseminated by the European Union on a right-to-know basis and this is not a publication in the same sense as a book or an article in a journal. The right of ownership in any part of this information is reserved by the data owner(s). The use of this information for any other, e.g. commercial purpose is strictly reserved to the data owners and those persons or legal entities having paid the respective access fee for the intended purpose.

Description of key information

BNMA proved to be readily biodegradable and fulfilling the 10-d window criterion.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

One study on biodegradation of BNMA is available, which is considered as reliable without restrictions (Klimisch score 1):

The ready biodegradation of BNMA was investigated in a study conducted according to OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test) adopted 17 July 1992 and EU Method C.4-C, 31 July 1992, over a period of 28 days using sewage sludge sampled from the aeration tank of a predominantly domestic sewage treatment plant as inoculum. The biodegradation rate was determined by measurement of CO2 evolution. Inoculum blank and procedural/functional control with the reference substance sodium acetate were performed.

After 28 days the degradation of BNMA reached 74%. The functional control reached the pass level >60% after 14 d. BNMA proved to be readily biodegradable and fulfilling the 10-d window criterion.