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Environmental fate & pathways

Biodegradation in water: screening tests

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Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 18. May to 02. June 2009
Reliability:
1 (reliable without restriction)
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
Harlan Laboratories Ltd., Quality Assurance GLP, Zelgliweg 1, 4452 Itingen, Switzerland
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of activated sludge:
wastewater treatment plant (ARA Ergolz II, Füllinsdorf / Switzerland) treating predominantly domestic wastewater
- Storage conditions:
room temperature
- Pretreatment:
The sludge was washed twice with tap water by centrifugation and the supernatant liquid phase was decanted. A homogenized aliquot of
the final sludge suspension was weighed, thereafter dried and the ratio of wet to dry weight was calculated
- Concentration of sludge:
30 mg dry material per liter
Duration of test (contact time):
14 d
Initial conc.:
30.4 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation:
DOC removal
Reference substance:
benzoic acid, sodium salt
Parameter:
% degradation (DOC removal)
Value:
98
St. dev.:
2.8
Sampling time:
3 d
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
Due to the fact that > 98 % of Glyoxylic Acid 50 % were degraded within the 10-d window of the incubation period, the test item can be classified as readily biodegradable under the conditions of this study.
Executive summary:

In a Ready Biodegradability study (OECD 301 A) Glyoxylic Acid 50% was assessed over a 14 day period by the DOC die away test. The nominal test concentration was 30.4 mg/L. The test material attained > 98 % biodegradation after 3 and 10 days, respectively. The reference compound sodium benzoate showed a mean biodegradability of > 90 % within 7 days, thus confirming suitability of the activated sludge.

These results indicate that Glyoxylic Acid 50% is readily biodegradable under conditions of the test.

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
1985
Reliability:
2 (reliable with restrictions)
Qualifier:
according to guideline
Guideline:
other: IRCHA; Exp. AFNOR Norm T90 302
GLP compliance:
no
Oxygen conditions:
aerobic
Inoculum or test system:
other: according to Norm T90 302
Duration of test (contact time):
14 d
Initial conc.:
39.27 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation:
DOC removal
Reference substance:
other: Glucose
Parameter:
% degradation (DOC removal)
Value:
ca. 99
Sampling time:
3 d
Parameter:
% degradation (DOC removal)
Value:
95.5
Sampling time:
7 d
Parameter:
% degradation (DOC removal)
Value:
98.1
Sampling time:
14 d
Results with reference substance:
3 days = 97.6 %
7 days = 92.2 %
14 days = 96.8 %
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
Readily biodegradable

Description of key information

> 98 % of Glyoxylic Acid 50 %  were degraded within a 10-d incubation period and is therefore readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Additional information

In a Ready Biodegradability study (OECD 301 A) Glyoxylic Acid 50% was assessed over a 14 day period by the DOC die away test. The nominal test concentration was 30.4 mg/L. The test material attained > 98 % biodegradation after 3 and 10 days, respectively. These results indicate that Glyoxylic Acid 50% is readily biodegradable under conditions of the test.

The reference compound sodium benzoate showed a mean biodegradability of > 90 % within 7 days, thus confirming suitability of the activated sludge.