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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:
2010-01-18 to 2010-04-14
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study performed according to OECD 301b and EU C.4.C under GLP conditions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report date:
2010

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
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
3-chloropropane-1,2-diol
EC Number:
202-492-4
EC Name:
3-chloropropane-1,2-diol
Cas Number:
96-24-2
Molecular formula:
C3H7ClO2
IUPAC Name:
3-chloropropane-1,2-diol
Details on test material:
- Name of test material (as cited in study report): 3-Chloro-1,2 propane diol
- Physical state: Liquid
- Composition of test material, percentage of components: 3-chloro-1,2-propane diol, > 98%
- Analytical purity: 99,3% (GC)
- Purity test date: 99,3% (GC)
- Lot/batch No.: 5225
- Expiration date of the lot/batch: 17/11/2010
- Storage condition of test material: Stored in a closed vessel at room temperature protected from light
- Other: date of production: 17 Nov 2009

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge: Activation basin of the ESN (Stadtentsorgung Neustadt) seawage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf
- Pretreatment: the sludge was filtrated, washed with tap water twice, then washed with and re-suspended in test medium. It was then aerated for ≥12 hours. The dry matter was determined with 3780 mg suspended solids/litre
- Concentration of inoculum during experiment: 25 mg/L
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
61.63 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Composition of medium: solution A (10 mL) + solution B (1 mL) + solution C (1 mL) + solution D (1 mL) + H2O demin. (1000 mL)
- Test temperature: 22 ± 2 °C
- pH: 7.1-7.3
- Aeration of dilution water: purified (by activated charcoal), CO2-scrubbed, moistened air

TEST SYSTEM
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: aeration with purified (by activated charcoal), CO2-scrubbed, moistened air
- Measuring equipment: carbon analyser TOC multi N/C 2100S, Analytik Jenar
- Details of trap for CO2 and volatile organics if used: Two scrubbers containing 100 mL in 0.25-m-NaOH each

SAMPLING
- Sampling frequency: on day 0, 2, 4, 7, 9, 11, 14, 18, 22 and 29
- Sampling method: The emitted CO2 was trapped in 0.25 M NaOH. Two scrubbers containing 100 mL each were connected in series to the test vessels. the initial inorganic carbon (IC) content of the 0.25 M NaOH was seperately determined in each flask. From each front scrubber flask, ten samples were taken in order to determine the emitted CO2 on days 0, 2, 4, 7, 9, 11, 14, 18, 22 and 29. the sample volume was 1 mL. The resulting change in the volume of the front flask was considered in the calculation of emitted CO2. On day 28.5 mL HCl 2-M was added to each test flasks in order to drive off dissolved CO2. On day 29, samples from both scrubber flasks were taken.

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2, containing mineral medium and inoculum
- Abiotic sterile control: 1, containing test item, mineral medium and HgCl2
- Toxicity control: 1, containing test item, positive control, mineral medium and inoculum
- Positive control: 2, containing positive control, mineral medium and inoculum
Reference substance
Reference substance:
aniline

Results and discussion

Preliminary study:
Not applicable
Test performance:
All validity criteria were met:
IC content of test item solution in medium: <1% (criterion: <=5% of TC)
CO2 emitted by the controls: 8.2 mg/L (criterion: <70 mg/L)
Difference within replicates: 1.2% (criterion: <=20%)
Degradation of positive control >60%: 9 days (criterion: <14 days)
Degradation in the toxicity flask on day 14: 62% (criterion: >25%)
% Degradationopen allclose all
Parameter:
% degradation (CO2 evolution)
Value:
77.1
Sampling time:
28 d
Remarks on result:
other: Mean of two replicates (76.5% and 77.7%)
Parameter:
% degradation (CO2 evolution)
Value:
66.5
Sampling time:
18 d
Remarks on result:
other: End of 10-day window period (mean of two replicates, 64.6% and 68.4%). 10 day window began on day 7
Details on results:
Degradation behaviour of positive control and toxicity control was normal. Abiotic degradation was 3%. Both replicates of the test item showed very good correspondence. Degradation in the toxicity flask lay between degradation in the positive controls and degradation in the test flasks, as was expected. If degradation in the toxicity flask is below 25% after 14 days, the test item can be considered as toxic towards the inoculum. This was not the case as degradation was 62% after 14 days.

BOD5 / COD results

Results with reference substance:
On day 29, the mean degradation was 82.4%.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The 10-day-window began on day 7 (9.7 and 12.6% degradation), at its end, 66.5% degradation was reached (64.6 and 68.4%), surpassing the pass level of 60% given in the OECD guideline. The test item 3-Chloro-1,2 propane diol is considered as "readily biodegradable".