Tyrosine

Biodegradation in water: screening tests

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 guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: Standard Methods German Waste Water Law for COD

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Sapromat for BOD

Test guideline 3

Qualifier:

according to guideline

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

Test material information

Constituent 1

Reference substance name:

Tyrosine

EC Number:

200-460-4

EC Name:

Tyrosine

Cas Number:

60-18-4

Molecular formula:

C9H11NO3

IUPAC Name:

tyrosine

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 concentration

Initial test substance concentration 1

Initial conc.:

206 mg/L

Based on:

test mat.

Initial test substance concentration 2

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 / COD

BOD5 / COD 1

Key result

Parameter:

BOD5*100/COD

Value:

60.8 other: %

BOD5 / COD 2

Parameter:

COD

Value:

2 050 mg O2/g test mat.

BOD5 / COD 3

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.