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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:
30-09-1981
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1981
Report Date:
1981

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
other: Standard Methods German Waste Water Law for COD
Qualifier:
according to
Guideline:
other: Sapromat for BOD
Qualifier:
according to
Guideline:
other: Offhaus: Biological degradation-inhibition
Principles of method if other than guideline:
Chemical oxygen demand (COD) was assessed by standard methods. The biochemical oxygen demand (BOD) was analysed using a Sapromat BOD measuring unit. The BOD after 5 days was determined. Biological degradation-inhibition was performed according to the Offhaus method.
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
not specified
Remarks:
No data on activated sludge given.
Duration of test (contact time):
5 d
Initial test substance concentrationopen allclose all
Initial conc.:
206 mg/L
Based on:
test mat.
Initial conc.:
422.3 mg/L
Based on:
COD
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption

Results and discussion

% Degradation
Key result
Parameter:
% degradation (O2 consumption)
Value:
60.8
Sampling time:
5 d

BOD5 / COD results

BOD5 / CODopen allclose all
Key result
Parameter:
BOD5*100/COD
Value:
60.8 other: %
Parameter:
COD
Value:
2 050 mg O2/g test mat.
Parameter:
BOD5
Value:
1 248 mg O2/g test mat.

Any other information on results incl. tables

The BOD5 test showed good biological degradation. The test item was degraded 60.8 % after a short exposure of 5 days.

The inhibition study showed negligible inhibition (1 %) and was decreasing.

Based on the observed respiration activity, it is expected that the biodegradation should take place undisturbed, even at higher concentrations and especially after certain adaptation.

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Interpretation of results:
readily biodegradable
Conclusions:
The BOD5/COD*100 = 60.8%. L-Tyrosince can be considered as readily biodegradable as the ultimate biodegradability exceeds 50 % within 5 days.
Executive summary:

In this study, the biochemical oxygen demand (BOD) was analysed using a Sapromat BOD measuring unit and compared to the chemical oxygen demand (COD). Biological degradation-inhibition test was performed using the Offhaus method. It is not a GLP study and no OECD guideline was followed.

After 5 days, the BOD5 was determined to be 1248 mg O2/g for L-tyrosine (COD = 2050 mg O2/g). The test is showing good biological degradation, i.e. 60.8 % after 5 days. L-tyrosine can be considered as readily biodegradable as the ultimate biodegradability exceeds 50 % within 5 days.

The inhibition study showed negligible inhibtion of 1 % and decreasing.

Based on the observed respiration activity, the degradation should take place undisturbed, even at higher concentrations and especially after certain adaptation.