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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
Study period:
From 6 March 2013 to 7 October 2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: According to the OECD Guideline and it is GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report Date:
2013

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Physical state: clear colorless liquid
- Storage condition of test material: room temperature in the dark

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
sewage, predominantly domestic, non-adapted
Details on inoculum:
A mixed population of sewage treatment micro-organisms was obtained on 14 June 2013 from the final effluent stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK, which treats predominantly domestic sewage.
The sample of effluent was filtered through coarse filter paper and maintained on aeration in a temperature controlled room at 21±1ºC prior to use.
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
test mat.
Details on study design:
The test item at a concentration of 100 mg/L was exposed to sewage treatment micro-organisms with mineral medium in sealed culture vessels in diffuse light at 22±1ºC for 28 days.
The degradation of the test item was assessed by the measurement of daily oxygen consumption values on Days 0 to 28. Control solutions with inoculum and the reference item, aniline, together with a toxicity control were used for validation purposes.

Preparation of Test System:
The following test preparations were prepared and inoculated mineral medium to act as the inoculum control
a) Three replicate bottles containing inoculated mineral medium to act as the inoculum control.
b)Two replicate bottles containing inoculated mineral medium and the reference item, aniline, at a concentration of 100 mg/L.
c) Three replicate bottles containing inoculated mineral medium and the test item at a concentration of 100 mg/L.
d) Two replicate bottles containing inoculated mineral medium the reference item, aniline, at a concentration of 100 mg/L and the test item at a concentration of 100 mg/L to act as toxicity control vessels.

All vessels were inoculated with the prepared inoculum at a rate of 1% v/v.
Reference substance
Reference substance:
aniline

Results and discussion

% Degradation
Value:
91

BOD5 / COD results

Results with reference substance:
Aniline (procedure control) attained 77% degradation after 14 days and 76% degradation after 28 days thereby confirming the suitability of the inoculum and test conditions.

Any other information on results incl. tables

BOD and Biodegradation Values

Sample Description ThOD Day 7  Day 14  Day 28
BOD (mg O2/L) Degradation (%) BOD (mg O2/L) Degradation (%) BOD (mg O2/L) Degradation (%) Mean Biodegradation (%)
Inoculum Control  R1 - 12,5 - 26,94 - 69,34 ¡- -
R2 - 13,28 - 29,66 - 78,52 -
Procedure Control   309 220,04 67 265,06 77 308,54 76 -
Test Item R1 292 22,86 3 224,36 67 320,04 84 91
R2 292 49,68 13 278,48 86 360,86 98
Toxicity Control    601 207,58 32 441,78 69 543,28 78 -

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The test item attained 91% degradation after 28 days and satisfied the 10 -Day window validation criterion, whereby 60% degradation must be attained within 10 days of the degradation rate exceeding 10%. The test item can therefore be considered to be readily biodegradable under the stric terms and conditions of OECD Guideline No.301F.
Executive summary:

The study was performed to assess the ready biodegradability of the test item in an aerobic aqueous media. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (1992) No. 301F, "Ready Biodegradability; Manometric Respiratory Test" refered as method C.4-D of Commission Regulation (EC) No. 440/2008.

The test item at a concentration of 100 mg/L was exposed to sewage treatment micro-organisms with mineral medium in sealed culture vessels in diffuse light at 22±1ºC for 28 days.

The degradation of test item was assessed by the measurement of daily oxygen consumption values on Days 0 to 28. Control solutions with inoculum and the reference item, aniline, together with a toxicity control were used for validation purposes.

The test item attained 91% degradation after 28 days and satisfied the 10 -Day window validation criterion, whereby 60% degradation must be attained within 10 days of the degradation rate exceeding 10%. The test item can therefore be considered to be readily biodegradable under the stric terms and conditions of OECD Guideline No.301F.