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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: GLP guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report Date:
2007

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

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
A sample of activated sludge was collected from the aeration tank at Worlingworth sewage treatment works, which treats predominantly domestic
waste. Aliquots (25 ml) of a homogenised sample were filtered through dried (approximately 105°C) and pre-weighed Whatman GF/C filter papers.
The filters were dried for at least one hour, allowed to cool and re-weighed. The solids level in the sludge was determined and then an appropriate
volume used to inoculate control and test vessels to give a final suspended solids concentration of 30 mg/l
Duration of test (contact time):
29 d
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
Mean cumulative CO2 production by the mixtures containing VRT-126017 dcha was equivalent to 10% of the TCO2 after approximately 7 days and 54% by the end of the test on Day 29.
The pH of each test and control mixture was 7.6 at the start of the test and ranged from 7.4 to 7.6 at the end.
The rate of air flow during the test ranged from 40 to 75 ml/minute.
The temperature of a three-litre volume of water held under the test conditions ranged from 21.7°C to 22.7°C during the test period
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradationopen allclose all
Parameter:
% degradation (CO2 evolution)
Value:
0
Sampling time:
2 d
Parameter:
% degradation (CO2 evolution)
Value:
13
Sampling time:
8 d
Parameter:
% degradation (CO2 evolution)
Value:
47
Sampling time:
17 d
Parameter:
% degradation (CO2 evolution)
Value:
53
Sampling time:
28 d
Parameter:
% degradation (CO2 evolution)
Value:
54
Sampling time:
29 d

BOD5 / COD results

Results with reference substance:
23 % degradation after 2 d
45 % degradation after 4 d
61 % degradation after 6 d
68 % degradation after 8 d
71 % degradation after 9 d
73 % degradation after 10 d
75 % degradation after 13 d
78 % degradation after 17 d
81 % degradation after 22 d
84 % degradation after 28 d
85 % degradation after 29 d

Applicant's summary and conclusion

Conclusions:
The mean cumulative CO2 production by mixtures containing VRT-126017 dcha at 9.4 mgC/l was equivalent to 10% of the TCO2 after approximately 7 days and 54% by the end of the test on Day 29. The test item cannot considered to be readily biodegradable.