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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:
26.02.-25-03.1992
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Name and location of sewage treatment plant where inoculum was collected: laboratory plant treating predominantly municipal sewage (treatment plant Neuenfelde)
- addition of 100 g standard soil from the Speyer region.
- Pre-treatment: filtration through rough flter
- Initial concentration: 3E+4 colony forming units/mL
Duration of test (contact time):
28 d
Initial conc.:
1.48 mg/L
Based on:
test mat.
Details on study design:
- Test temperature: 20 +- 1 °C
- control flask: destilled water with mineral nutrient solution without inoculum
- blind flask: destilled water with mineral nutrient solution with inoculum
- reference flask: a solution of sodium-n-dodecylsulfat with mineral nutrient solution and inoculum
- degradation test: a solution of the test item with mineral nutrient solution and inoculum
- inhibition test: a solution ofthe test item, sodium-n-dodecylsulfat with mineral nutrient solution and inoculum

The oxygen concentration of the test solutions was determined electrochemically after 0, 5, 15, 28 days.
Reference substance:
laurylsulfonate
Key result
Parameter:
% degradation (O2 consumption)
Value:
6
Sampling time:
28 d

Table 1: Results

mg O2 after x dayys
Medium Bottle 0 days 5 day 15 days 28 days
mineral nutrient solution without test item and inoculum K1 9,01 8,99 8,95 8,92
mineral nutrient solution without test item and inoculum K2 9,02 8,99 8,96 8,92
mineral nutrient solution without test item and inoculum Mean 9,02 8,99 8,96 8,92
mineral nutrient solution without test item and with inoculum B1 9,01 8,97 8,95 8,92
mineral nutrient solution without test item and with inoculum B2 9,00 8,96 8,94 8,91
mineral nutrient solution without test item and with inoculum Mean 9,01 8,97 8,95 8,92
mineral nutrient solution with test item and with inoculum concentration 1,58 mg/L S1 9,00 8,88 8,74 8,64
mineral nutrient solution with test item and with inoculum concentration 1,48 mg/L S2 9,01 8,88 8,77 8,62
mineral nutrient solution with test item and with inoculum concentration 1,48 mg/L Mean 9,01 8,88 8,76 8,63
mineral nutrient solution with reference substance and with inoculum concentration 2,0 mg/L R1 9,02 7,53 6,32 5,44
mineral nutrient solution with reference substance and with inoculum concentration 2,0 mg/L R2 9,01 7,51 6,35 5,47
mineral nutrient solution with reference substance and with inoculum concentration 2,0 mg/L Mean 9,02 7,52 6,34 5,46
mineral nutrient solution with test item (1,48 mg/L) reference substance (2,0 mg/L) and inoculum concentration H1 9,00 7,52 6,33 5,64
mineral nutrient solution with test item (1,48 mg/L) reference substance (2,0 mg/L) and inoculum concentration H2 9,00 7,55 6,37 5,64
mineral nutrient solution with test item (1,48 mg/L) reference substance (2,0 mg/L) and inoculum concentration Mean 9,00 7,54 6,35 5,64

Table 2: Results of the closed bottle test

 Substance  degradation after 5 days   degradation after 15 days   degradation after 28 days
 Reference Substance  36%  65%  87%
 Test item  2% 4%  6% 

 

The test item was not determined to be readily biodegradable.

The test item showed weak inhibitory potential.

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
The test substance degraded to 6% within 28 days. Therefore, the substance is considered to be classified as "not readily biodegradable".
Executive summary:

A Closed Bottle Test on ready biodegradability was conducted according to OECD Guideline 301 D. The validity criteria was fulflilled, as the reference substance laurylsulfonate degraded to 87% after 28 days. The test substance was applied at 1.48 mg/L and degraded to 6% after 28 days. Therefore, the substance is considered be classified as "not readily biodegradable".

Description of key information

The test substance degraded to 6% within 28 days. Therefore, the substance is considered to be classified as "not readily biodegradable".

Key value for chemical safety assessment

Biodegradation in water:
not biodegradable
Type of water:
freshwater

Additional information

A Closed Bottle Test on ready biodegradability was conducted according to OECD Guideline 301 D. The validity criteria was fulflilled, as the reference substance laurylsulfonate degraded to 87% after 28 days. The test substance was applied at 1.48 mg/L and degraded to 6% after 28 days. Therefore, the substance is considered be classified as "not readily biodegradable".