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Environmental fate & pathways

Biodegradation in water: screening tests

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Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
See attachment
Cross-referenceopen allclose all
Reason / purpose:
read-across source
Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
14/04/2010 - 12/05/2010
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:
1992
GLP compliance:
yes (incl. certificate)
Specific details on test material used for the study:
Code: HGZX20100318-0098
Receptor date: 2010-03-22
Conditions of storage: Keep in the original container (plastic bag) protecting from moisture at 20°C
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, industrial (adaptation not specified)
Details on inoculum:
Collection: a fresh sample of activated sludge from Jiangqiao Wastewater Treatment Plant, aerated until using.
Treatment: washed 3 times with mineral medium. The sludge was separated by centrifuging for 20 minutes at 4000rpm. The washed sludge was weighed at 0.204g, then dried at 105°C for 1h to calculate the dry weight which was 7.53%.
Sludge suspension: Wet sludge was suspended in mineral medium to obtain the concentration of 3 g dry matter/L. Stirred at 500rpm by magnetic sterring for 30min, the final concentration in test solution was 30 mg/L.
Duration of test (contact time):
ca. 28 d
Initial conc.:
<= 30 mg/L
Parameter followed for biodegradation estimation:
other: BOD
Reference substance:
other: sodium benzoate (SCRC)
Key result
Parameter:
other: abiotic degradation
Value:
ca. 16.55
Sampling time:
28 d
Key result
Parameter:
% degradation (CO2 evolution)
Value:
10.65
Sampling time:
28 d
Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
During the 10-day windows exposure period, the mean biodegradation of test substance amounted to 11.47% or 10.65% with correction for nitrification, so that the test substance was found to be non-readily biodegradable under the present test conditions within 28 days. Abiotic degradation percent was 16.55%
Executive summary:

The readily biodegradability of the test substance SXjul2006 (HGZ20100318 -0098) was determined manometric respirement test in a 28 days. The biochemical oxygen demand (BOD) of test substance didn't increase during the test period of 28 days. During 10 -days window, the mean biodegradation percent without nitrification of test substance amounted to 11.47% and with nitrification amounted to 10.65%, couldn't reach pass level of ready biodegradability. The substance amount had non-readily biodegradability under the test conditions within 28 days.

Reason / purpose:
read-across source
Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
30/08/2006 - 28/09/2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)
Version / remarks:
European Community, Commission directive 92/69/EEC, Part C: Methods for the determination of ecotoxicity, Publication No. L383, December 1992, C.4. Biodegradation: determination of the 'ready' biodegradability, C.4-C: Carbon dioxide (CO2) evolution test (modified Sturm test)
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Version / remarks:
Organisaton for Economic Co-operation and Development (OECD), OECD guidelines for Testing of Chemicals, Section 3, Degredation and Accumulation, guideline No. 301 B: "Ready Biodegradability: CO2 Evolution Test" adopted July 17, 1992
Qualifier:
according to
Guideline:
other: ISO Standard 9439
Version / remarks:
ISO Standard 9439, Water Quality - Evaluation of ultimate aerobic biodegradability of organic compounds in aqueous medium - carbon dioxide evolution test (1999)
GLP compliance:
yes (incl. certificate)
Specific details on test material used for the study:
Stability in water Not indicated
Solubility in water Poorly
Oxygen conditions:
aerobic
Inoculum or test system:
sewage, domestic (adaptation not specified)
Details on inoculum:
Source:
The source of test organisms was activated sludge freshly obtained from a municipal sewage treatment plant: 'Waterschap de Maaskant', 's-Hertogenbosch, the Netherlands, receiving predominantly domestic sewage.

Treatment:
The sludge was kept under continuous aeration until further treatment. The concentration of suspended solids was 3.7 g/l in the concentrated sludge (information obtained from the municipal sewage treatment plant). Before use, the sludge was allowed to settle (62 minutes) and the liquid was decanted for use as inoculum at the amount of 10 ml/l of mineral medium.
Duration of test (contact time):
>= 28 d
Initial conc.:
ca. 3.7 g/L
Based on:
other: information obtained from the municipal sewage treatment plant
Reference substance:
other: Sodium acetate
Key result
Parameter:
% degradation (CO2 evolution)
Value:
ca. 1
Sampling time:
14 d
Parameter:
% degradation (CO2 evolution)
Value:
ca. 4
Sampling time:
29 d
Parameter:
% degradation (CO2 evolution)
Value:
ca. 6
Sampling time:
29 d
Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
SXjul2006 wat not readily biodegradable under the conditions of the modified Sturm test presently performed.

Data source

Materials and methods

Test material

Reference
Name:
Unnamed
Test material form:
solid
Details on test material:
- Stabilisation: stable
- Safety precautions: The routine hygienic procedures were sufficient to assure personnel health and safety
- Colour: brownish red
- Storage conditions: room temperature

Results and discussion

% Degradationopen allclose all
Key result
Parameter:
% degradation (CO2 evolution)
Value:
<= 10
Sampling time:
10 d
Key result
Parameter:
% degradation (CO2 evolution)
Value:
<= 16
Sampling time:
28 d

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable