N-(N6-trifluoroacetyl-L-lysyl)-L-proline

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1992-12-17 to 1993-03-31

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)

Version / remarks:

1990

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Preparation of inoculum for exposure: The original sludge was homogenized and contained about 2.8 g of solid substance per
litre. 193 mL of the mixed sludge was used to inoculate 18 litres of medium (yielding about 30 mg of solid substance L-1).
- Concentration of sludge: 2.8 g/L

Duration of test (contact time):

28 d

Initial conc.:

10 mg/L

Based on:

test mat.

Initial conc.:

20 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium:
Add to one litre water 10 ml of solution A and 1 mL of solutions B to F.
a) Solution A contains per litre:
KH2PO4 8.5 g
K2HPO4 21.8 g
Na2HPO4 x 2 H2O 33 .4 g
NH4Cl 1.5 g
b) Solution B contains 22.5 g of MgSO4 x 7 H2O per litre.
c) Solution C contains 27.5 g of CaCl2 x 2 H2O per litre.
d) Solution D contains 0.15 g of FeCl3 per litre.
e) Trace element solution.
This solution contains per litre water:
MnSO4 x 4 H2O 39.9 mg
H3BO3 57.2 mg
ZnSO4 x 7 H2O 42.8 mg
(NH4)6Mo7O24 34.7 mg
EDTA 100.0 mg
f) 15 mg yeast extract dissolved in 100 mL water.
Sterilize solutions A, B, C and E. Solutions D and F are prepared freshly before use.
- Test temperature: 20 ± 2 °C
- pH: 7.6 ± 0.4
- pH adjusted: no
- Aeration of dilution water: Yes, 24h before the start of the test
- Continuous darkness: yes

TEST SYSTEM
- Number of culture flasks/concentration: duplicate
- Measuring equipment: O C International 700 TOC analyzer
- Test performed in open system: Two litre erlenmeyer flasks (Scott Duran), closed with a foam cap

SAMPLING
- Sampling frequency: 0, 7, 14, 21, 28 days
- Sterility check if applicable: sterility control flask contained uninoculated medium, 10 mg test substance and 5 mL 1% mercury(II)chloride solution.
- Sample storage before analysis: The samples were placed in scintillation vials (20 mL) and frozen (-20°C) pending analyses.

CONTROL AND BLANK SYSTEM
- Inoculum blank: Control flasks without test substance to allow correction for the background DOC in the medium were included in duplicate.
- Abiotic sterile control: Yes, a sterile control was included in the test; this flask contained uninoculated medium, 10 mg test substance and
5 mL 1% mercury(II)chloride solution.
- Toxicity control: In order to detect possible toxic effects of the test substance, sodium acetate (100 mg/L) was also added to further duplicate flasks containing 10 and 20 mg/L of ε-trifluoracetyl-L-lysyl-L-proline (TFA-Lys-Pro).

Reference substance:

acetic acid, sodium salt

Parameter:

% degradation (DOC removal)

Value:

52

Sampling time:

7 d

Parameter:

% degradation (DOC removal)

Value:

93

Sampling time:

14 d

Key result

Parameter:

% degradation (DOC removal)

Value:

100

Sampling time:

28 d

Details on results:

The results of this test show that, as expected, acetate was completely degraded (99%) within one week.There were no effects of the test substance of the acetate degradation. The test substance degraded up to 99% within 28 days in this test. The second criterium for ready biodegradability (the 10 day window) was also met

Results with reference substance:

99 % degradation after 7 d (DOC removal)
100 % degradation after 14 d (DOC removal)
100 % degradation after 21 d (DOC removal)

Results ofthe biodegradation tests with ε-trifluoracetyl-L-lysyl-L-proline (TFA-Lys-Pro).

	ε-trifluoracetyl-L-lysyl-L-proline (mg/L)
	10		20
	mg DOC	%DOC removal	mg DOC	%DOC removal
0	3.4	-	7.2	-
7	1.6	52	1.0	86
14	0.3	93	1.0	86
21	0.4	90	0.6	92
28	-0.2	100	0.2	98

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

In a study conducted according to OECD guideline 301E (1990) the biodegradability was determined by DOC removal. The test substance degraded up to 99% within 28 days in this test. The second criterium for ready biodegradability (the 10 day window) was also met.
It was therefore concluded that ε-trifluoracetyl-L-lysyl-L-proline (TFA-Lys-Pro) can be regarded as readily biodegradable in this test.

Description of key information

In a study conducted according to OECD guideline 301E (1990) the biodegradability was determined by DOC removal. ε-trifluoracetyl-L-lysyl-L-proline (TFA-Lys-Pro) degraded up to 99% within 28 days in this test. The second criterium for ready biodegradability (the 10 day window) was also met.

Therefore, ε-trifluoracetyl-L-lysyl-L-proline (TFA-Lys-Pro) can be regarded as readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater