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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:
2010-04-22 to 2010-06-08
Reliability:
1 (reliable without restriction)

Data source

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

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Deviations:
yes
Remarks:
A deviation to the study plan n°09/1175F/a is recorded in this study: Experimental completion date indicated has not been respected. This deviation has not any influence on results detailed in this report.
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): 2237 JG
- Substance type: Surfactant
- Physical state: White solid appearence
- Analytical purity: 100%
- Purity test date: February 18th 2010
- Lot/batch No.: 2237 JG
- Expiration date of the lot/batch: December 2011
- Stability under test conditions: Stable
- Storage condition of test material: Room temperature





Study design

Oxygen conditions:
aerobic
Remarks:
8.8 mg/L dissolved oxygen
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 "Louis Fargue", Bordeaux (France)- April 22th 2010
- Laboratory: FCBA
- Storage conditions: aerated reservoir
- Preparation of inoculum for exposure:
Filtration
4 successive decantation into mineral medium
activated sludge areration during 5 days
- Concentration of sludge:
0.90 g/L suspended solid
pH=7.4
Dissolved oxygen : 8.8mg/L
- Water filtered: yes
- Type and size of filter used, if any: 5 mm
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
other: nominal sol source of organic carbon
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Remarks:
ThOD
Details on study design:
The test was performed on a measured volume of inoculated mineral medium (250mL), containing the test item at 10 mg/L (directly added in flask after a period of 20 minutes of ultrasonication) as the nomila sol source of organic carbon and stirred in closed flasks at a constant temperature (20+/- 1°C) for up to 28 days.
Microbial respiration consumes O2 and releases CO2 which is absorbed by soda lime pellets present in the haedspace of flasks. This produces a decrease in pressure in the flask proportional to the amount of oxygen taken up by the microbial population during biodegradation, which was expressed as a percentage of ThOD (Theoretical Oxygen Demand).
Allowance was made for the endogenous activity of the inoculum by running parallel blancks with inoculum but without test item. Furthemore, in order to check the procedure, a reference compounds control (sodium benzote + inoculum) and a toxicity control (sodium benzoate + inoculum + test item) were run in parallel.
This test was performed in duplicate for the test item. pH of the contents was measured at the start and the end of the experiment.
The oxygen consumption is recorded every 112 minutes for each flask
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

Preliminary study:
No data
Test performance:
All validity criteria given by the OECD 301F guideline were respected:
Oxygen uptake of the inoculum control was not greater than 60 mg/L
Variation between the two test item replicates was inferior to 20% at the end of the test
reference item showed a biodegradability superior to 60% within 14 days
pH values were comprised between 6 and 8.5
% Degradation
Parameter:
% degradation (O2 consumption)
Value:
67.3
Sampling time:
28 d

BOD5 / COD results

BOD5 / COD
Parameter:
BOD5
Value:
ca. 2 mg O2/g test mat.
Results with reference substance:
BOD reference : 1.54 mgO2/mg at day 28
BOD toxic control : 1.75 mgO2/mg at day 28
BOD test item : between 2.1 and 1.81 mgO2/mg at day 28

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The substance is readily biodegradable.
Executive summary:

Readly biodegradability of the test item "2237 JG" was performed according to the OECD 301F guideline. The results obtained show that the test item biodegradability reached at the end of the sudy (i.e. 28 days), the 60% pass level was not reached in a 10 days windows.Because the substance is a UVCB and according to paragraph 4.1.2.9.5 of the regulation 286/2011 amending the CLP regulation 1272/2008, the 10 -day window does not have to be taken into account for this kind of substance. Therefore the substance is ready biodegradable.

 

 

   Replicate 1  Replicate 2  Average Value
 Maximal degree of biodegradability  72.3%  62.3%  67.3%
 10 % biodegradability  day 2  day 2  day 2
 60% biodegradability  day 18  day 23  day 20