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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: Well documented study according to international accepted guideline and GLP compliant.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2015
Report Date:
2015

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: crystalline
Details on test material:
Test item: 4-nitrophenyl-acetic acid
CAS number: 104-03-0
EC number: 203-168-5
Molecular formula: C8H7NO4
Molecular weight: 181.15 g/mol
Physical state: solid, crystalline powder
Storage: cool, dry place, protected from light

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
Type of inoculum: aerobic mixed bacterial culture
Source: Municipal wastewater treatment plant, Esztergom-Kertváros
Duration of test (contact time):
28 d
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
PREPARATION OF INOCULUM TEST CULTURE
Before preparation of inoculum test culture, the dry substance content of the stock culture was determined. The measured value was 7.3 g/L.
250.0 ml inoculum test culture with 1.0 g/L dry substance was made by mixing 34 ml of stock culture with 216 ml mineral medium.

PREPARATION OF REFERENCE SOLUTION
For the reference solution 320.17 mg sodium acetate was diluted in 100 ml mineral medium.

PREPARATION OF TEST VESSELS
Following test vessels were prepared and analysed for the study:
- Test item (in two replicates)
- Blank control (in two replicates)
- Reference solution (positive control)
- Reference and test item solution (toxicity control)
- Sterilized solution of test item (abiotic control)

The test vessels were tightly closed with measuring heads and placed into thermostat. The temperature during the test was adjusted to 21 ± 1 °C. The vessels were kept in complete darkness and they were stirred continuously.
The vessels were kept in thermostat for 28 days.
Reference substance
Reference substance:
acetic acid, sodium salt

Results and discussion

% Degradation
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
28 d
Remarks on result:
other: mean of two replicates

BOD5 / COD results

Results with reference substance:
Reference solution (positive control): 79%
Reference and test item solution (toxicity control): 40%
Sterilized solution of test item (abiotic control): 4%

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
other: not readily biodegradable
Conclusions:
According to OECD guideline the test item should be classified as readily biodegradable if the percentage biodegradation reaches 60% of theoretical oxygen demand within 28 day period in a 10-day window. Based on ready biodegradability testing results the test item 4-nitrophenyl-acetic acid is not readily biodegradable.