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Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guidleine study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Report date:
2012

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
GLP compliance:
yes (incl. QA statement)

Test material

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Colony forming units (CFU): 1.5 x 10E9 CFU/L
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
30 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Test temperature: 20.5-21.5°C
- pH: 7.98 to 7.51
- pH adjusted: no

TEST SYSTEM
- Culturing apparatus: 500 mL brown glass bottles
- Measuring equipment:
OxiTop'" OC110 controller, WTW
OxiTop'" measuring heads, WTW
Stirring platform , WTW
Incubator, RUBARTH
pH-Meter, Multi 350i,WTW
Thermohygrograph, LUFFT
Analytical balance, SARTORIUS
Balance, EW 3000-2M, KERN

SAMPLING
- Sampling frequency: the oxygen consumption was determined continously during the 28 days incubation period
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradation
Parameter:
% degradation (O2 consumption)
Value:
28
Sampling time:
28 d
Details on results:
Both test item replicates reached the 10 % level (beginning of biodegradation) after 2 days, but failed to reach the pass level of 60 % biodegradation.
The mean biodegradation on day 28 was 28 %

BOD5 / COD results

Results with reference substance:
In order to check the activity of the test system sodium benzoate was used as functional control. The pass level> 60 % was reached after 1 day. The biodegradation rate reached a maximum of 100 % degradation on day 17.

Any other information on results incl. tables

In the toxicity control containing both test and reference item 65 % degradation occurred within 14 days. After 28 days the biodegradation came to 69 %. The degradation of the reference item was not inhibited by the test item.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The test item is classified as not readily biodegradable in the 10-d-window and after 28 days