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Environmental fate & pathways

Biodegradation in water: screening tests

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Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1990
Report date:
1990

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)
GLP compliance:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
2-hexyloxyethanol
EC Number:
203-951-1
EC Name:
2-hexyloxyethanol
Cas Number:
112-25-4
Molecular formula:
C8H18O2
IUPAC Name:
2-(hexyloxy)ethanol
Details on test material:
- Name of test material (as cited in study report): N-Hexylglykol
- Analytical purity: 98 %
- Impurities (identity and concentrations): up to 0.2% Diethylenglycole-monobutylether, 0.1% Diethylenglycole, 0.1% Diethylenglycole-monohexylether

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
sewage, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Municipal activated sludge taken from a laboratory wastewater treatment plant fed with municipal sewage
Duration of test (contact time):
8 d
Initial test substance concentration
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 SYSTEM
- Culturing apparatus:
- Number of culture flasks/concentration: 6

CONTROL AND BLANK SYSTEM
- Inoculum blank: 3
- Abiotic sterile control: 3
- Toxicity control: 3
- reference substance: 3

Concentration of test substance: 32 mg/l = 20 mg/l DOC
Water: 500 ml
Nutrient solution: 6 ml
Inoculum: 0.5 ml
33.9 ml stock solution
Additional water: 427.3 - 493.5 ml
Total volume: 1000 ml
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradation
Parameter:
% degradation (DOC removal)
Value:
86
Sampling time:
8 d
Details on results:
Kinetic of test substance (in %):
= 3.3 after 1 day
= 85.4 after 5 days

BOD5 / COD results

Results with reference substance:
PC control: 12 % DOC after 8 days
Reference control: 99 % after 5 days

Applicant's summary and conclusion

Interpretation of results:
readily biodegradable