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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
February 12, 2009 - June 23, 2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
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)
Specific details on test material used for the study:
Name: Disodium hydroxy(sulfonato)acetate
Batch no.: 080129
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
Activated sludge from a biologic sewage treatment plant was used. The chosen plant is treating mostly domestic sewage.

The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt)
sewage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf.
Date of collection: 08. May 2009, batch no: 08052009.

The sludge was filtrated, washed with tap water twice, then washed with and re-suspended
in test medium. lt was then aerated for 2: 12 hours. The dry matter was determined
with 4580 mg suspended solids/litre.
Duration of test (contact time):
28 d
Initial conc.:
173.4 mg/L
Based on:
test mat.
Parameter:
% degradation (CO2 evolution)
Value:
3.6
Sampling time:
2 d
Parameter:
% degradation (CO2 evolution)
Value:
65.9
Sampling time:
4 d
Parameter:
% degradation (CO2 evolution)
Value:
93.4
Sampling time:
7 d
Parameter:
% degradation (CO2 evolution)
Value:
94
Sampling time:
29 d
Details on results:
The test item is considered as “readily biodegradable“.
The degree of biodegradation reached 94 % after 28 days.
The 10-day-window began on day 3, at its end, 94 % were reached, surpassing the pass level of 60 % given in the OECD guideline.
Abiotic degradation was not observed.
All validity criteria were met.
Degradation behaviour of positive control and toxicity control was normal. Abiotic degradation was not observed. Both replicates of the test item showed very good correspondence. Degradation took place completely and rapidly.
If degradation in the toxicity flask is below 25% after 14 days, the test item can be considered as toxic towards the inoculum. As degradation in the toxicity flask was 88% after 14 days, the test item can be stated as “not toxic towards the inoculum in a concentration of 173.4 mg/l”.
The result of the test can be considered valid.
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The test item Disodium hydroxy(sulfonato)acetate is considered as “readily biodegradable“.
Executive summary:

The test item Disodium hydroxy(sulfonato)acetate is considered as “readily biodegradable“.

Description of key information

 The test item Disodium hydroxy(sulfonato)acetate is considered as "readily biodegradable".

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Additional information