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Environmental fate & pathways

Biodegradation in water: screening tests

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Endpoint:
biodegradation in water: screening test, other
Remarks:
BOD, COD
Type of information:
other: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
From September 15, 1993 to September 22, 1993
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study without detailed documentation
Remarks:
The test was conducted on a similar substance. The complete justification for the read across is attached at section 13.
Qualifier:
according to
Guideline:
EU Method C.6 (Degradation: Chemical Oxygen Demand)
Version / remarks:
DEV DIN 38'409 - H 41-1 (1980) corresponding to 92 / 96 / EEC C.6.
Deviations:
yes
Remarks:
Mean of 2 determinations instead of 3
Principles of method if other than guideline:
Internal method: SAV: 02 000 02
GLP compliance:
yes (incl. certificate)
Oxygen conditions:
not specified
Inoculum or test system:
not specified
Duration of test (contact time):
ca. 2 h
Reference substance:
other: Potassium hydrogen phthalate solution
Remarks on result:
not determinable
Parameter:
COD
Value:
1 412 mg O2/g test mat.
Results with reference substance:
The COD of Potassium hydrogen phthalate is (Criteria: 200 ± 8 mg O2/I) : 201 mg O2/I

COD = 1412 mg O2/g

Validity criteria fulfilled:
not applicable
Interpretation of results:
other: not applicable
Conclusions:
The COD of test item is 1412 mg O2/g
The COD of the reference substance is 201 mg O2/I
Executive summary:

The test was carried out according to DEV DIN 38'409 - H 41-1 (1980) corresponding to 92/96/EEC C.6. The test was performed in compliance with the Good Laboratory Practice (GLP) Regulations of Switzerland.

A predeterminated amount of the test substance in water is oxidized by potassium dichromate in a strong sulphuric acid medium with silver sulphate as a catalyst under reflux for 2 hours. The residual dichromate is determined by titration with standardized ferrous ammonium sulphate.

The test substance was tested with a sample weight of 7.39 + 7.11 mg. The reference substance Potassium hydrogen phthalate solution was tested in a concentration of 20 ml/I.

The COD of test item is 1412 mg O2/g

The COD of the reference substance is 201 mg O2/I

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
other: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
From November 17, 1993 to December 01, 1993
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
The test was conducted on a similar substance. The complete justification for the read across is attached at section 13.
Qualifier:
according to
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
Deviations:
yes
Remarks:
(instead of 28 d the test has been finished after 14 d since no degradation activity could be observed)
Qualifier:
according to
Guideline:
other: EEC-Directive, 79/831, Annex V, C.7. ABIOTIC DEGRADATION HYDROLYSIS AS A FUNCTION OF PH
Principles of method if other than guideline:
Internal method: SAV : 06 000 02
GLP compliance:
yes (incl. certificate)
Oxygen conditions:
aerobic
Inoculum or test system:
sewage, domestic (adaptation not specified)
Details on inoculum:
Strain / Inoculation: Mixture of polyvalent bacteria collected in the aeration tank of a domestic sewage treatment plant, ARA Basel Communal
Bacteria concentration: 30 mg/L
Duration of test (contact time):
ca. 14 d
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
Water/Nutrient: According to the specification of the test method
Temperature: 20 ± 2 °C
Lighting: None
Estimation Technique: Voith Sapromat; O2-Consumption automatically measured
Reference substance:
benzoic acid, sodium salt
Parameter:
% degradation (O2 consumption)
Value:
ca. 0
Sampling time:
14 d
Details on results:
The biodegradation of test substance (corrected by the inoculum control) expressed as the % of BOD versus ThOD was 0 % (14 d).
Results with reference substance:
The biodegradation (corrected by the inoculum control) expressed as the % of BOD versus ThOD was 91 % (14 d).

Validity CRITERIA:

The degradation after 14 days of the reference substance (Natriumbenzoat) has to be higher than 65 %.

Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
Under the study conditions, the test substance was not readily biodegradable.
Executive summary:

The ready biodegradability of the test substance was determined in a 14 d MITI test (I) according to OECD Guideline 301C (1981) and the EU Method C.7. Both the test substance and reference substance sodium benzoate were tested at a concentration of 100 mg/l. Biodegradation was equivalent to 0 and 91 %, respectively. Under the study conditions, the test substance was not readily biodegradable.

Description of key information

Not readily biodegradable

Key value for chemical safety assessment

Additional information