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Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: inherent biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
May 28th to July 4th 2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: done under OECD method and GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2014
Report Date:
2014

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: Solid
Details on test material:
Off-white solid
Stored at normal temperature

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
The fresh activated sludge used in the test was collected from Wuzhong district urban area sewage treatment plant . The address of the plant is No. I , Baodai East Road, Suzhou city. The batch No. of inoculum was AS-20140529-0 I.

The activated sludge was washed with test medium after removing the suspended solids and coarse particles on the day of collection, the activated sludge was centrifuged at 1 100 g for 5 minutes, and the supernatant was discarded. Repeated the process for 3 times.

The dry weight content of the activated sludge was determined in triplicates after pre-treatment, and the average value was 9.91%.
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Test temperature: 22±2 'C . Monitor the temperature daily, and its range was 2 1 .0-23.7'C.
- pH: 6.79-7.39
- Aeration of dilution water: 6.04-8.68 mg/L
- Continuous darkness: yes

TEST SYSTEM
- Number of culture flasks/concentration: 5 liter glass bottles, covered with aluminium foil to keep dark. 3 liters per container which will be aerated and stirred-According to the test guideline 3028, the concentration of prepared activated sludge based on dry weight must be in the range 0.2-1 .0 g/L, and the concentration of test substance based on DOC must be between 50 mg/L and 400 mg/L. Moreover, the ratio of activated sludge and test substance must be kept in the range 2.5: I and 4: I . Therefore, 0.4 g/L of activated sludge (by dry weight) and 100 mg/L of test substance (by DOC) were used in the test, and its ratio was 4:I.

SAMPLING
Determined the DOC, pH and dissolved oxygen by Total Organic Carbon Analyzer on 3h ± 30rni n , day 0, l , 5, 8, 1 1, 14, 18, 22, 27 and 28 after the test performed. 50 mL of sample will be taken immediately prior to each sampling, replace losses due to evaporation by the concave surface marking.

CONTROL AND BLANK SYSTEM
- Inoculum blank: none
- Procedure control: diethylene glycol
- Test suspension: test substance (boronic acid)
Reference substance
Reference substance:
diethylene glycol

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
16.67
Sampling time:
28 d
Details on results:
Points of degradation plot (test substance): 11.92 % degradation on 14 d and 16.67 % degradation on 28 d.

BOD5 / COD results

Results with reference substance:
Points of degradation plot (reference substance): 98.01 % degradation on 14 d.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
inherently biodegradable, fulfilling specific criteria
Conclusions:
The test material attained 16.67% degradation after 28 days and therefore can be considered to be inherently biodegradable under the strict terms and conditions of OECD Guideline No 302B.