Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
29 August 2017 to 26 September 2017
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
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
Version / remarks:
2008
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 835.3110 (Ready Biodegradability)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
A mixed population of sewage treatment micro-organisms was obtained on 23 August 2017 from the final effluent stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK, which treats predominantly domestic sewage
Duration of test (contact time):
28 d
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Composition of medium: mineral medium according to OECD guideline
- Additional substrate: no
- Solubilising agent (type and concentration if used): no
- Test temperature: between 22 and 24 ºC
- pH: 7.4 (on day 28)
- pH adjusted: no

TEST SYSTEM
- Culturing apparatus: sealed culture vessels in diffuse light
- Number of culture flasks/concentration: three replicates (test item and inoculum control), two resplicates (reference item, toxicity control)
- Measuring equipment: CES Multi-Channel Aerobic Respirometer

SAMPLING
- Sampling frequency: daily

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control:: yes
Reference substance:
aniline
Key result
Parameter:
% degradation (O2 consumption)
Remarks:
Theoretical Oxygen Demand
Value:
0
Sampling time:
28 d
Details on results:
The mean BOD of the inoculated mineral medium (control) was 26.24 mg O2/L after 28 days and therefore satisfied the validation criterion given in the OECD Test Guidelines.
The pH of the inoculated test item vessels on Day 28 were 7.4 and hence satisfied the validation criterion given in the OECD Test Guidelines.
The difference between extremes of replicate BOD values at the end of the test was less than 20% and therefore satisfied the validation criterion given in the OECD Test Guidelines.
The test item attained 0% biodegradation after 28 days, calculated from the oxygen consumption values, and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301F.
The toxicity control attained 36% biodegradation after 14 days and 42% biodegradation after 28 days thereby confirming that the test item was not toxic to the sewage treatment micro-organisms used in the test.
Results with reference substance:
Aniline (procedure control) attained 72% biodegradation after 14 days and 77% biodegradation after 28 days thereby confirming the suitability of the inoculum and test conditions.
Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
The test item attained 0% biodegradation after 28 days and therefore cannot be considered as readily biodegradable under the strict terms and conditions of OECD Guideline No. 301F.
Executive summary:

The test item attained 0% biodegradation after 28 days, calculated from the oxygen consumption values, and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301F.

The mean BOD of the inoculated mineral medium (control) was 26.24 mg O2/L after 28 days and therefore satisfied the validation criterion given in the OECD Test Guidelines.

The pH of the inoculated test item vessels on Day 28 were 7.4 and hence satisfied the validation criterion given in the OECD Test Guidelines.

The difference between extremes of replicate BOD values at the end of the test was less than 20% and therefore satisfied the validation criterion given in the OECD Test Guidelines.

The toxicity control attained 36% biodegradation after 14 days and 42% biodegradation after 28 days thereby confirming that the test item was not toxic to the sewage treatment micro-organisms used in the test.

.

Description of key information

The test substance cannot be considered as readily biodegradable based on data obtained in a GLP study using the manometric test in accordance with OECD Guideline 301F, EU Method C.4 -D and US EPA procedure OPPTS 835.3310.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

In the toxicity control containing both, the test item and the reference item Sodium benzoate, a mean of 32.7 % biodegradation was noted within 14 days and 42.1 % biodegradation after 28 days of incubation. According to the test guidelines the test item can be assumed to be not inhibitory at the applied concentration level of 2.7 mg/L on the activated sludge microorganisms because degradation was >25 % within 14 days.