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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:
1995-03-17 to 1995-05-12
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: in the BODIS test, the following is different compared to OECD TG 301 D: the inoculum amounted to 30 mg dry weight sludge suspension/L, temperature was 18-22 °C, the ThOD/L: was > 5-10 g.
Qualifier:
according to
Guideline:
ISO 10708 Water quality - Evaluation in an aqueous medium of the ultimate aerobic biodegradability of organic compounds - Determination of biochemical oxygen demand in a two-phase closed bottle test
Deviations:
no
GLP compliance:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: sewage treatment plant Hochdahl, Germany, supporting of 28000 population equivalents, > 80 % reduction of chemical oxygen demand (COD)
- Laboratory culture: Culturing of approx. 30 mg activated sludge dry weight/L within approx. 200 mL nutrient solution
- Method of cultivation: incubation with flasks
- Storage conditions: 18-22 ° C (pre-incubation)
- Storage length: one week (pre-incubatuion)
- Preparation of inoculum for exposure: nutrition solution, one week cultivated with activated sludge, under oxygen saturation
- Pretreatment: no
- Concentration of sludge: approx. 20 mg of test item per flas or 100 mg of test item per liter, calculated on the basis of chemical oxygen demand
- Initial cell/biomass concentration: 100 mg of COD of test item per liter
- Water filtered: no
- Type and size of filter used, if any: no filter used
Duration of test (contact time):
28 d
Initial conc.:
100 mg/L
Based on:
COD
Parameter followed for biodegradation estimation:
DOC removal
Parameter:
% degradation (DOC removal)
Value:
2
St. dev.:
2
Sampling time:
7 d
Remarks on result:
other: SD rcaculated from the data
Parameter:
% degradation (DOC removal)
Value:
29
St. dev.:
10
Sampling time:
14 d
Remarks on result:
other: SD rcaculated from the data
Parameter:
% degradation (DOC removal)
Value:
69
St. dev.:
5
Sampling time:
20 d
Remarks on result:
other: SD rcaculated from the data
Key result
Parameter:
% degradation (DOC removal)
Value:
84
St. dev.:
6
Sampling time:
28 d
Remarks on result:
other: SD recaculated from the data
Parameter:
COD
Value:
2 668 mg O2/g test mat.

Table 1 % oxidation of the test item

 replicate day 7  day 14  day 20  day 28
 1 4 39 71 88 
 2 1 29  71 87
 3 0 20  62 77
 mean 2  29  68 84

 

Table 2 % oxidation of natrium acetate

 replicate day 7  day 14  day 21  day 28
 1 57 66 70 87
 2 70 78 84 84
 3 69 80 85  86
 mean  65  74  80  85
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
In a reliable, valid and conclusive study, the test substance Sandelriechstoff (27-4828) was readily biodegradable according to the BODIS test, a modified closed bottle test.
Executive summary:

The test item Sandelriechstoff (27-4828) was tested for its potential of ready biodegradation under aerobic conditions in the BODIS test, which is considered as suitable for the assessment of test substances with poor solubility on water. Under the test conditions, the test item showed an oxygen demand of 84 % (Biological oxygen demand BOD after 28 days/Chemical oxygen demand). Since the 14 -day window was met (as mentioned in the OECD TG 301 for closed bottle test), the test substance Sandelriechstoff (27 4828) is considered as readily biodegradable.

Description of key information

The test item was tested for its potential of ready biodegradation under aerobic conditions in the BODIS test, which is considered as suitable for the assessment of test substances with poor solubility on water. Under the test conditions, the test item showed an oxygen demand of 84 % (Biological oxygen demand BOD after 28 days/Chemical oxygen demand). Since the 14 -day window was met (as mentioned in the OECD TG 301 for closed bottle test), the test substance Sandelriechstoff (27 4828) is considered as readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Additional information

[Type of water: freshwater]