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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:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
19 June 1990 - 4 January 1991
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
This study is used as cross reference. Due to the similarity between enzymes, the same conclusion can be reached for deoxyribonuclease.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report date:
1991

Materials and methods

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

Test material

Constituent 1
Reference substance name:
Active enzyme protein of Lipase, triacylglycerol (EC no. 232-619-9, CAS no. 9001-62-1, EC name: Lipase, triacylglycerol, Enzyme Class No.: 3.1.1.3)
Cas Number:
9001-62-1
Molecular formula:
Not applicable, see remarks
IUPAC Name:
Active enzyme protein of Lipase, triacylglycerol (EC no. 232-619-9, CAS no. 9001-62-1, EC name: Lipase, triacylglycerol, Enzyme Class No.: 3.1.1.3)
Constituent 2
Reference substance name:
Protein as a constituent of enzyme deriving from the fermentation or extraction process
Molecular formula:
Not available
IUPAC Name:
Protein as a constituent of enzyme deriving from the fermentation or extraction process
Constituent 3
Reference substance name:
Inorganic salts as a constituent of enzyme deriving from the fermentation or extraction process
Molecular formula:
Not available. See remarks.
IUPAC Name:
Inorganic salts as a constituent of enzyme deriving from the fermentation or extraction process
Constituent 4
Reference substance name:
Carbohydrates constituent of enzyme deriving from the fermentation or extraction process
Molecular formula:
Not available. See remarks.
IUPAC Name:
Carbohydrates constituent of enzyme deriving from the fermentation or extraction process
Constituent 5
Reference substance name:
Lipids as a constituent of enzyme deriving from the fermentation or extraction process
Molecular formula:
Not available. See remarks.
IUPAC Name:
Lipids as a constituent of enzyme deriving from the fermentation or extraction process
Test material form:
liquid
Details on test material:
- Lot/batch No.: LAJR 009-12
- Expiration date of the lot/batch: 1 August 1998
- Storage condition of test material: -20 degrees Celcius

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge: The aeration stage of the HRC Limited sewage treatment plant treating predominantly domestic sewage.
- Preparation of inoculum for exposure: The aerated sample was filtered through a coarse filter paper (first approximately 200 mL discarded) and used on day of collection.
- Concentration of sludge: 0.5 mL of inoculum per litre dilution water
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
250 mg/L
Based on:
test mat.
Initial conc.:
ca. 40 mg/L
Based on:
ThIC
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
DOC removal
Details on study design:
TEST CONDITIONS
- Composition oftest medium: 1000 mL dilution water plus 1 mL nutrient solutions (a)-(f): (a) potassium dihydrogen phosphate: 8.5 g/L; di-potassium hydrogen phosphate: 21.75 g/L; di-sodium monohydrogen phosphate dihydrate: 33.4 g/L; ammonium chloride: 20 g/L), (b) magnesium sulphate heptahydrate (22.5 g/L), (c) calcium chloride (27.5 g/L), (d) iron(III)chloride hexahydrate (0.25 g/L), (e) Mangan sulphate tetrahydrate (39.9 mg/L), boric acid (57.2 mg/L), zinc sulphate heptahydrate (42.8 mg/L), ammonium molybdate tetrahydrate (36.85 mg/L) and (f) Yeast extract 15 mg/100 mL; plus 0.5 mL inoculum plus sufficient test substance. This is diluted to 2 litres with dilution water.
- Test temperature: 22 ± 1°C
- Continuous darkness: yes

TEST SYSTEM
- Number of culture flasks/concentration: 2 controls, 2 test substance and 2 reference substance
- Method used to create aerobic conditions: Aeration by magnetic stirrers and compressed air via narrow bore glass tubes.
- Measuring equipment: IONICS TC/TOC Analyser model 555.
- Test performed in open system: yes


SAMPLING
- Sampling frequency: day 0, 1,3, 7, 14, 21, 27 and 28
- Sampling method: Samples (ca. 20 mL) were withdrawn from each vessel and filtered through Sartorius Minisart NML, 0.45 µm disposable filters, discarding the first 10 mL.
- Sample storage before analysis: Samples were analysed directly


CONTROL AND BLANK SYSTEM
- Inoculum blank: inoculated test medium


Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradationopen allclose all
Parameter:
% degradation (DOC removal)
Value:
44
Sampling time:
1 d
Key result
Parameter:
% degradation (DOC removal)
Value:
79
Sampling time:
3 d
Parameter:
% degradation (DOC removal)
Value:
92
Sampling time:
14 d
Key result
Parameter:
% degradation (DOC removal)
Value:
99
Sampling time:
28 d

BOD5 / COD results

Results with reference substance:
Sodium benzoate achieved 79 % degradation within 3 days and 95% degradation within 28 days.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
Under the conditions of the test Lipase SP 400 was found to be readily biodegradable.
Executive summary:

Lipase SP 400 was assessed for ready biodegradability according to OECD Guideline 301E and EEC Directive 67/548 Annex V C.3 as published in 84/449/EEC, and in compliance with GLP.

SP 400 achieved 79% biodegradation within 3 days and 99% biodegradation within 28 days. The pass level of 70% was thus reached within 10 days of exceeding the 10% level.

The reference substance attained 95% biodegradation within 28 days, thereby confirmiung the suitability of the inoculum and the culture conditions.

In conclusion, SP 400 was found to be readily biodegradable under the conditions of the test.