Registration Dossier

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:
1996
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: according to OECD 301B (Sturm test); experimental part equivalent to GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996
Report Date:
1996

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Qualifier:
according to
Guideline:
EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)
GLP compliance:
no
Remarks:
experimental part acc. to GLP standards but no quality control, sample storage and GLP certificate

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
Origin of inoculum: municipal sewage treatment plant Frankfurt- Sindlingen, Germany
Source: washed activated sludge of municipal sewage treatment
Preparation of suspension: activated sludge sediment centrifugated twice and resuspended in de-ionized water
Used quantity of inoculum: 10 ml/L suspended sludge
Pretreatment: acc. to guideline; pre-aeration of supernatant for 5 days to deactivate carbon dissolved in activated sludge
Preconditions: not pre-adapted to the test substance and the reference material
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
25.8 mg/L
Based on:
test mat.
Initial conc.:
26.42 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
Due to the low solubility of the tested substance no stock solution was prepared. The tested substance was added directly to the test flasks.
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
0
Sampling time:
28 d
Details on results:
The value %Degr. is the mean value of two test flasks with two different initial concentrations of the test substance (see section: initial test substance concentration);
The %Degr. value is based on the ratio of determined CO2 formation and the theoretical CO2 formation.
Determinded values were corrected by control values from a blank test performed without any testing substance.
The CO2-evolution of the blank test was below 50 mg/L after 28 days.

BOD5 / COD results

Results with reference substance:
The reference test using benzoic acid sodium salt as reference substance provided a CO2-evolution of more than 60% within 14 days (mean value of 2 tests in 2 test flasks). The %Degr. value is based on the ratio of determined CO2 formation and the theoretical CO2 formation.
The CO2-evolution of the blank test was below 50 mg/L after 28 days.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
The test item is not (readily) biodegradable.
Executive summary:

The ready biodegradability of Naphtol AS-ITR was tested using a non adapted activated sludge in the CO2 evolution test for a period of 28 days according to OECD guideline 301 B.

No (ready) biodegradation was found (%Degr. = 0)

The validity criteria of the guideline are fulfilled.