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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-Guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Phenylguanidine carbonate monohydrate
- Physical state: Solid / grey
- Homogeneity: Homogeneous
- Analytical purity: 100 area-%, determined by HPLC chromatography The identity of the test substance was confirmed by 1H-NMR spectroscopy (BASF report No. 10L00155)
- Lot/batch No.: KG1/511.feucht
-Storage stability: The stability under storage conditions over the exposure period was guaranteed by re-analysis (BASF report No. 10L00155)
- Storage condition of test material: Storage at room temperature
-Water solubility: In a preliminary test the amount of 122.4 mg test substance was added to a 1000 mL volumetric flask. After addition of about 600 mL demineralized water the sample preparation was stirred and made up to the mark. The test substance was completely dissolved, verified by measurement of DOC and TOC.

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Municipal activated sludge from the wastewater treatment plant of Mannheim, Germany.
- Storage conditions: aerated in the laboratory until use
- Preparation of inoculum for exposure: sieved by finely woven mesh with a mesh size about 1 mm. After settling
the supernatant was discarded and the sludge suspension was filled up with tap water
- Pretreatment: pre-aerated for about 24 hours at room temperature
- Concentration of sludge: The sludge of the suspension was adjusted to a concentration of 6.0 g/L dry weight. Aliquots of 5 mL were added to the test vessels to obtain a sludge concentration of 30 mg/L dry substance.
Duration of test (contact time):
20 d
Initial test substance concentrationopen allclose all
Initial conc.:
50 mg/L
Based on:
test mat.
Initial conc.:
20 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
DOC removal
Details on study design:
TEST CONDITIONS
- Composition of medium:
- Test temperature: 22 +/- 2°C
- pH adjusted: yes
- Aeration: For aeration the test vessels were shaken at a temperature of 22 ± 2°C using an orbital shaker.

TEST SYSTEM
- Number of culture flasks/concentration: 2
- Test performed in open system: yes

SAMPLING
- Sampling frequency: twice per week
- Sampling method: The samples for DOC-analysis were centrifuged for about 15 minutes at 4000 rpm.
- Sample storage before analysis:The samples were analyzed on the day of sampling.

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2
- Abiotic sterile control:1
- Toxicity control: 1
- Other: 1 inhibition control assay and 1 assay for control of adsorption

Results and discussion

% Degradation
Parameter:
% degradation (DOC removal)
Value:
90 - 100
Sampling time:
20 d
Details on results:
The test substance is readily biodegradable in this test

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable