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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:
experimental study
Adequacy of study:
key study
Study period:
1986
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study, confidence level significantly enhanced through comparison with other included chemicals. Also mentioned in OECD SIDS
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Unnamed
Year:
1986
Reference Type:
publication
Title:
A method to classify biodegradabilities of organic compounds
Author:
Urano K, Kato Z
Year:
1986
Bibliographic source:
J Hazardous Materials 13, 135-145

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
Deviations:
yes
Remarks:
Duration =<14 d; evaluation/rating system different from standard criteria of today
Principles of method if other than guideline:
Respirometry Test (BOD of ThOD);
Electrolytic respirometer containing 30 mg/l activated sludge over a 14-day period at 20°C
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Molecular Formula: C3H7CHO
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Not relevant

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
concentration in test apparatus: 30 mg/L
Duration of test (contact time):
<= 14 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
Electrolytic respirometer;
pH of solution: 7 +/- 1;
culture mediums: JIS inorganic mediums, 1 mL/300 mL;
Temperature: 20 +/- 1°C;
period: within 14 days
Reference substance
Reference substance:
other: various substances (comparative study)

Results and discussion

Preliminary study:
No details supplied
Test performance:
No details supplied
% Degradation
Parameter:
other: BOD related to THOD
Value:
>= 46 - <= 57
Sampling time:
5 d
Remarks on result:
other: 90-135 hours of incubation = 3.75 - 5.7 days, assumed to correspond to a mean of 5 days
Details on results:
Incubation time: 90-135 hours;
rate constant of the geometrical biodegradation: 0.044-0.069 * 1/h;
lag time: approx. 5 h

BOD5 / COD results

Results with reference substance:
For example:
Benzoic acid BOD/ThOD = 0.61 - 0.69 within 65 - 80 h
Butyric acid BOD/ThOD = 0.58 - 0.82 within 135 - 140 h

Any other information on results incl. tables

No details supplied

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Interpretation of results:
readily biodegradable
Conclusions:
In a comparative biodegradation screening applying MITI(I) test conditions, n-butanal was readily biodegradable, shown by a BOD elimination within about 4 to 6 days of 46 to 56 % in relation the added Theoretical Oxygen Demand (ThOD) of 100 mg test substance/L.

For comparison, the BOD/ThOD ratio of benzoic acid was 0.61 - 0.69 within approx. 3 days (stated 65 - 80 h), while the BOD/ThOD ratio of butyric acid was found to be 0.58 to 0.82 within approx. 6 days (stated 135 - 140 h).
Executive summary:

In a comparative biodegradation screening applying MITI(I) test conditions, n-butanal was readily biodegradable, shown by a BOD elimination within about 4 to 6 days of 46 to 56 % in relation the added Theoretical Oxygen Demand (ThOD) of 100 mg test substance/L.

For comparison, the BOD/ThOD ratio of benzoic acid was 0.61 - 0.69 within approx. 3 days (stated 65 - 80 h), while the BOD/ThOD ratio of butyric acid was found to be 0.58 to 0.82 within approx. 6 days (stated 135 - 140 h).