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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:
7 May 2008 - 4 June 2008
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Version / remarks:
1994
Qualifier:
according to
Guideline:
other: SS-EN ISO 9408:2000
GLP compliance:
no
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
Activated sludge from Klagshamn wastewater plant in Malmö, Sweden.
The concentration of suspended solid: 4.5 g/L.
The final conentration of suspended solids in the mediums was 30 mg/L.
Duration of test (contact time):
28 d
Initial conc.:
0.045 other: mL/L
Based on:
test mat.
Initial conc.:
101 mg/L
Based on:
COD
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
A closed manometric respirometer (Hach) was used. The equipment contained six bottles and each of them was connected to a manometer. The contents in the bottles were stirred with a magnetic stirrer. During the degradation, organic material was reduced, oxygen was consumed and carbon dioxide was produced. Since the produced carbon dioxide was trapped in potassium hydroxide, the oxygen consumption led to a decrease in the pressure, which was monitored by the manometer. Pressure changes within the closed manometric system were displayed directly in milligrams per liter (mg/L), Biochemical Oxygen Demand (BOD) on a precalibrated scale. Four direct-reading scales were provided with the apparatus. The required volume of medium and the required scale depended on the test substance's expected BOD value.
Reference substance:
other: sodium acetate
Key result
Parameter:
% degradation (CO2 evolution)
Value:
>= 62 - <= 64
Sampling time:
28 d
Remarks on result:
other: Percentage biodegradation of COD
Details on results:
The pass value of 60% for readily biodegradability has been been reached in a 10-day window within the 28-day period of test. This means that the substance can be regarded as readily biodegradable.
Results with reference substance:
The % degradation of the reference substance was 65 % within the 28-day period of testing.
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The pass value of 60% for readily biodegradability in the OECD 301F test has been been reached in the 10-day window within the 28-day period of the test on Dermosoft DGMC. This means that the test substance can be regarded as readily biodegradable.
Executive summary:

The aerobic biodegradability of Dermosoft DGMC was tested in a study performed according to OECD 301F Manometric Respirometry Test. The validation criteria of the test were fulfilled.

According to OECD guidelines for testing of chemicals, a test substance is regarded as readily biodegradable if the removal of ThOD within 28 days is greater than 60%. The pass value has to be reached in a 10-day window within the 28-day period of the test. The 10-day window begins when the degree of biodegradation has reached 10% ThOD and must end before 28 day of the test. This criterion was reached for the test substance (biodegradation of 62 - 64%), which means that it can be regarded as readily biodegradable.

Description of key information

The pass value of 60% for readily biodegradability in the OECD 301F test has been reached in the 10-day window within the 28-day period of the test on Dermosoft DGMC. This means that the test substance can be regarded as readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Additional information

The pass value of 60% for readily biodegradability in the OECD 301F test has been reached in the 10-day window within the 28-day period of the test on Dermosoft DGMC. This means that the test substance can be regarded as readily biodegradable.