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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other: GLP-compliant guideline study available as unpublished report, no restrictions, fully adequate for assessment

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2006
Report Date:
2006

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)
Qualifier:
according to
Guideline:
EU Method C.4-A (Determination of the "Ready" Biodegradability - Dissolved Organic Carbon (DOC) Die-Away Test)
Qualifier:
according to
Guideline:
EPA OPPTS 835.3110 (Ready Biodegradability)
Qualifier:
according to
Guideline:
ISO 7827 (Evaluation in an Aqueous Medium of the "Ultimate" Aerobic Biodegradability of Organic Compounds - Method by Anlaysis of Dissolved Organic Carbon (DOC))
GLP compliance:
yes (incl. certificate)
Remarks:
BASF AG Experimental Toxicolgy and Ecology

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: liquid
Details on test material:
- Name of test substance (as cited in study report): 1,2,3,4-Tetrahydroisoquinoline
- Molecular formula: C9 H11 N
- Molecular weight: 133.1929
- Physical state / appearance: liquid / reddish-yellow
- Water solubility: 20 g/L
- Purity: 87.3 area-%
- Homogeneity: homogeneous
- Storage conditions: storage at room temperature
- Storage stability: The stability under storage conditions over the exposure period was guaranteed by the sponsor
- Test substance number: 05/0797-1
- Batch identification: LJ 32741/75
- Date of production: 10 Oct 2005

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
- Municipal activated sludge from the aeration tank of the wastewater treatment plant of Mannheim / Baden-Württemberg;
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
20 mg/L
Based on:
DOC
Initial conc.:
26 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
DOC removal
Details on study design:
BIOLOGICAL TEST SYSTEM
A suitable aliquot of the activated sludge suspension was washed with tap water, sieved by a finely woven mesh (mesh size about 1 mm) and pre-aerated for about 24 hours. The sludge of this suspension was adjusted to a concentration of 6.0 g/L dry weight and then added to the test vessels to obtain a sludge concentration of 30 mg/L dry substance.

EXPERIMENTAL PROCEDURE
The DOC Die Away test was performed in 2L conical flaks filled up to a volume of 1000 mL. For aeration the test vessels were shaken at a temperature of 22 ± 2°C using orbital shaker with about 150 rounds/minute. The following test vessels were prepared: Two flaks containing test substance in a concentration of about 20 mg/L Dissolved Organic Carbon and inoculum from a municipal treatment plant in a mineral medium, and two blank controls, only with mineral medium and inoculum. The further test flasks for inhibition control and controls for physical elimination as well as a flask with a well biodegradable reference substance for testing of the biological capacity of the inoculum are optionally. At begin of exposure samples are taken from all test vessels. The samples were centrifuged and the concentration of Dissolved Organic Carbon was determined in the aqueous supernatant. The DOC measurement was performed twice per week, these DOC-values were compared with the values from begin of exposure. The decrease of DOC concentration was expressed as biodegradation degree and plotted by a biodegradation curve.
Reference substance
Reference substance:
aniline

Results and discussion

% Degradation
Parameter:
% degradation (DOC removal)
Value:
< 10
Sampling time:
28 d
Remarks on result:
other: (mean value of two single values)
Details on results:
DEGRADATION DEGREE
- Biodegradation degree in inhibition control after 14 d (% DOC): 40 - 50
- Abiotic elimination of test substance (% DOC): < 10 at end of exposure
- Elimination of test substance by adsorption (% DOC): <10 after 5 d

BOD5 / COD results

Results with reference substance:
DEGRADATION DEGREE
- Biodegradation degree of reference substance after 14 d (% DOC): 90 - 100

Any other information on results incl. tables

VALIDITY CRITERIA

- Deviation of the degradation degree of the test substance in the plateau phase: <20%;

- Degradation degree of the reference substance: >70% DOC after 14 days;

- Degradation degree in the inhibition control: >35% DOC after 14 days;

The test is valid

Applicant's summary and conclusion