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Environmental fate & pathways

Biodegradation in water: screening tests

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Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well documented study according EEC C.4-'CO2 Evolution test' and OECD 301B.

Data source

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

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Qualifier:
according to
Guideline:
EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report):Benzenesulphonyl chloride (Provichem 0203)
- Analytical purity: 99.95%
- Lot/batch No.: 200911040020
- Storage condition of test material: Ambient room temperature 20 to 30°C

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Sludge collected from sewage treatment works, which treats predominantly domestic waste was aerated for 5 days and activated in the laboratory. Ten aliquots (50 mL) of homogenised samples were filtered through dried (approximately 100°C) and pre-weighed sintered crucible. The filters were dried for two hours (approximately 110°C), allowed to cool, and re-weighed. The solids level in the sludge was determined and then an appropriate volume was used to inoculate control and test vessels to give final suspended solids concentrations of 30 mg/L.
Duration of test (contact time):
29 d
Initial test substance concentration
Initial conc.:
10 mg/L
Based on:
other: mg C/L
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Composition of medium: inoculated mineral salt medium
- Milli-Q water was added to each of six, five-litre amber-glass culture bottles followed by the required volumes of each of the stock solutions of test medium to prepare three litre of mineral salts. After aeration of 5 days, the bottles were treated with test items Benzenesulphonyl chloride and sodium benzoate as reference standard. The pH of each culture medium was determined. Each vessel was was then fit to a stopper holding an air inlet tube reaching approximately 10 cm below the liquid surface and an air outlet just below the stopper.
-pH was measured for each test container at the beginning of the test and ranged between 6.01-6.40 and at the end 5.98-6.33. The rate of air-flow during the test was approximately 100mL/minute.
Reference substance
Reference substance:
other: sodium benzoate

Results and discussion

% Degradationopen allclose all
Parameter:
% degradation (CO2 evolution)
Value:
73
Sampling time:
14 d
Parameter:
% degradation (CO2 evolution)
Value:
92
Sampling time:
29 d
Details on results:
The biodegradation of sodium benzoate in the presence of the test item Benzenesulphonyl chloride (Provichem 0203) was monitored in order to assess whether any inhibitory effects were exerted on the activity of the microbial inoculum. The degradation showed that the test compound was not inhibitory. Items are considered to be readily biodegradable in this test if CO2 production is equal to or greater than 60% of the theoretical value within 14 days of achieving the 10% level. Benzenesulphonyl chloride (Provichem 0203) reached 73% degradation after 14 days when tested at a concentration of 10 mg C/L and therefore would be considered readily biodegradable. The results obtained for the degradation of sodium benzoate was 91% of its TCO2 after 29 days at 10 mg C/L and the cumulative CO2 production of 21-23 mg CO2 by the control mixtures fulfill the validity criteria for this test.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The biodegradation of sodium benzoate in the presence of the test item Benzenesulphonyl chloride (Provichem 0203) was monitored in order to assess whether any inhibitory effects were exerted on the activity of the microbial inoculum. The degradation showed that the test compound was not inhibitory. Items are considered to be readily biodegradable in this test if CO2 production is equal to or greater than 60% of the theoretical value within 14 days of achieving the 10% level. Benzenesulphonyl chloride (Provichem 0203) reached 73% degradation after 14 days when tested at a concentration of 10 mg C/L and therefore would be considered readily biodegradable. The results obtained for the degradation of sodium benzoate was 91% of its TCO2 after 29 days at 10 mg C/L and the cumulative CO2 production of 21-23 mg CO2 by the control mixtures fulfill the validity criteria for this test.