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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:
2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline Study with GLP
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
GLP compliance:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
Municipal sewage treatment plant, D-31137 Hildesheim
Colony forming units of the inoculum 10E+7 - 10E+8 CFU/L
Duration of test (contact time):
28 d
Initial conc.:
15 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
CO2 evolution
Reference substance:
acetic acid, sodium salt
Parameter:
% degradation (CO2 evolution)
Value:
97
Sampling time:
28 d
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
Regarding the biodegradation of the test item the 10 % level (beginning of biodegradation) was reached after 3 days. The biodegradation reached the pass level of 60 % on day 14. The mean biodegradation came to a maximum of 97 % after 28 days.
 
The validity criteria according to the guideline are fulfilled. The abidance of the 10-day window is not to be considered because the substance is a UVCB.

The test item must be regarded as readily biodegradable after 28 days.
Executive summary:

The ready biodegradability of the test item Fatty acids, C16-18-, reaction products with diethanolamine was determined with a non adapted activated sludge over a test period of 28 days in the Modified Sturm Test. The study was conducted from 2005-11-24 to 2005-12-23 according to OECD 301 B /CO2evolution test. The test item was tested with concentration of 15 mg/L in duplicates, corresponding to carbon content (TOC) of 11.0 mgC/L in the test vessels. The biodegradation of the test item was followed by titrimetric analyses of the quantity of CO2 produced by the respiration of bacteria. The degradation was finished on day 28 by acidification, the last titration was made on day 29, after the soluble CO2was turned out over a period of 24 h. the percentage CO2production was calculated in relation to the theoretical CO2(ThCO2) of the test item. The biodegradation was calculated to each titration time.

 

To check the activity of the test system sodium acetate was used as functional control. The percentage degradation of the functional control reached the pass level of 60% on day 6. In the toxicity control containing both test and reference item a biodegradation rate of 70 % occurred within 14 days and came to a maximum of 94 % after 28 days. The biodegradation of the reference item was not inhibited by the test item in the toxicity control.

 

Regarding the biodegradation of the test item the 10 % level (beginning of biodegradation) was reached after 3 days. The biodegradation reached the pass level of 60 % on day 14. The mean biodegradation came to a maximum of 97 % after 28 days.

 

The validity criteria according to the guideline are fulfilled. The abidance of the 10-day window is not to be considered because the substance is a UVCB.

The test item must be regarded as readily biodegradable after 28 days.

Description of key information

Regarding the biodegradation of the test item the 10 % level (beginning of biodegradation) was reached after 3 days. The biodegradation reached the pass level of 60 % on day 14. The mean biodegradation came to a maximum of 97 % after 28 days.

 

The validity criteria according to the guideline are fulfilled. The abidance of the 10-day window is not to be considered because the substance is a UVCB.

The test item must be regarded as readily biodegradable after 28 days.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

The ready biodegradability of the test item Fatty acids, C16-18-, reaction products with diethanolamine was determined with a non adapted activated sludge over a test period of 28 days in the Modified Sturm Test. The study was conducted from 2005-11-24 to 2005-12-23 according to OECD 301 B /CO2evolution test. The test item was tested with concentration of 15 mg/L in duplicates, corresponding to carbon content (TOC) of 11.0 mgC/L in the test vessels. The biodegradation of the test item was followed by titrimetric analyses of the quantity of CO2 produced by the respiration of bacteria. The degradation was finished on day 28 by acidification, the last titration was made on day 29, after the soluble CO2was turned out over a period of 24 h. the percentage CO2production was calculated in relation to the theoretical CO2(ThCO2) of the test item. The biodegradation was calculated to each titration time.

 

To check the activity of the test system sodium acetate was used as functional control. The percentage degradation of the functional control reached the pass level of 60% on day 6. In the toxicity control containing both test and reference item a biodegradation rate of 70 % occurred within 14 days and came to a maximum of 94 % after 28 days. The biodegradation of the reference item was not inhibited by the test item in the toxicity control.

 

Regarding the biodegradation of the test item the 10 % level (beginning of biodegradation) was reached after 3 days. The biodegradation reached the pass level of 60 % on day 14. The mean biodegradation came to a maximum of 97 % after 28 days.

 

The validity criteria according to the guideline are fulfilled. The abidance of the 10-day window is not to be considered because the substance is a UVCB.

The test item must be regarded as readily biodegradable after 28 days.

In a supporting study regarding OECD Guideline 302B the mean biodegradation came to a maximum of 88% after 28 days. Based on these results the test item be termed as ultimately biodegradable under the conditions of the OECD guideline no. 302, since more than 70 % degradation was attained after 28 days of contact time.