2-[[(2S)-2-(9H-fluoren-9-ylmethoxycarbonylamino)-3-(1H-imidazol-5-yl)propanoyl]amino]-2-methyl-propanoic acid Trifluoroacetic acid salt (1:1)

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:

10/01/2019 - 10/05/2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

GLP compliance:

yes

Specific details on test material used for the study:

Batch: 160004
Preparation date: 30/11/2016
Expiration date: 09/02/2020
Storage conditions: Refrigerated (2-8 °C)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Inoculum: activated sludge, domestic, not adapted Collect in Camposampiero ( PD) WT from Aerobic Aereation Re-circulation

Inoculum final concentration in every single bottle:
Suspended Solids ( 5.5.3.1) 24.7 mg/L
Microbiological Count (5.5.3.2.) UFC/L 5.7 x 10^7

Duration of test (contact time):

28 d

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Reference solution: in a 100 mL matrass 0.8087 g of Reference Item Sodium Benzoate (3.1) were weighted and adjusted to the final volume with water

Details on the test: In every bottle 3 litres of mineral medium were loaded with mL 10 of activated sludge and aerated for 24 hr with CO2 free air to reach suspended solids less than 30 mg/L. After 24 hr the test sample was added to yield a final concentration of 10-20 mgTOC/L. The bottles were prepared as described in the OECD guideline as follows:
- bottle 1 e 2 containing test substance weighted directly : 0.0881g and 0.0892g
- bottles 3 e 4 containing only inoculum (inoculum blank).
- bottles 5 e 6 containing the reference substance: 10 mL of the reference solution
Every bottle was adjusted to the final volume of 3 L with mineral medium.
IC content of the test substance suspension in the mineral medium at the beginning of the test was less than 5% of the TC.
Every single bottle was connected to 3 Drechsel laid out in line containing 100 ml of BaOH 0.0125 M
The system was aerated in continuous with CO2 free air with a flux between 30 mL/min e 100 mL/min
The degradation were registered for 28 days.
The system temperature was kept between 20°C-24°C.
The CO2 produced was trapped by Ba(OH)2 solutions.
Quantitative determination of CO2 was obtained titrating exceeding Ba(OH)2 with HCl 0.05 M using phenolphthalein as indicator.
During the first ten days titrations were made every second or third day and then at least every fifth day.

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (CO2 evolution)

Value:

25.8

Sampling time:

28 d

Remarks on result:

other: mean value of two replicates

Parameter:

% degradation (CO2 evolution)

Value:

14.1

Sampling time:

26 d

Remarks on result:

other: mean value of two replicates

Parameter:

% degradation (CO2 evolution)

Value:

10.3

Sampling time:

22 d

Remarks on result:

other: mean value of two replicates

Parameter:

% degradation (CO2 evolution)

Value:

9.8

Sampling time:

19 d

Remarks on result:

other: mean value of two replicates

Parameter:

% degradation (CO2 evolution)

Value:

9.8

Sampling time:

15 d

Remarks on result:

other: mean value of two replicates

Parameter:

% degradation (CO2 evolution)

Value:

8

Sampling time:

13 d

Remarks on result:

other: mean value of two replicates

Parameter:

% degradation (CO2 evolution)

Value:

5.1

Sampling time:

9 d

Remarks on result:

other: mean value of two replicates

Parameter:

% degradation (CO2 evolution)

Value:

3

Sampling time:

7 d

Remarks on result:

other: mean value of two replicates

Parameter:

% degradation (CO2 evolution)

Value:

-1.3

Sampling time:

5 d

Remarks on result:

other: mean value of two replicates

Parameter:

% degradation (CO2 evolution)

Value:

-1.2

Sampling time:

2 d

Remarks on result:

other: mean value of two replicates

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

0 d

Details on results:

Blank control: 18,4 mg CO2/litre

Results with reference substance:

Biodegradability of reference substance (after 28 days): 88,1%

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Test sample Biodegradation after 28 days < 60% ThCO2 so, according to OECD 301B, under the test condition applied the test substance is considered NOT READY BIODEGRADABLE.

Executive summary:

The OECD 301 B Screening Test Study aim at assessing the ready biodegradability in a laboratory system designed to represent either the aerobic treatment stage. A positive result in a test of ready biodegradability, it may be assumed that the chemical will undergo rapid and ultimate biodegradation in the environment.

A measured volume of inoculated mineral medium, containing a known concentration of the test substance (10-20 mg DOC or TOC/l) as the nominal sole source of organic carbon is aerated by the passage of carbon dioxide-free air at a controlled rate in the dark or in diffuse light. Degradation is followed over 28 days by determining the carbon dioxide produced.

The amount of carbon dioxide produced from the test substance (corrected for that derived from the blank inoculum) is expressed as a percentage of ThCO2.

Quantitative determination of CO2 was obtained titrating exceeding Ba(OH)2 with HCl 0,05 M using phenolphthalein as indicator.

The results after 28 days are:

-BIODEGRADABILITY OF TEST SUBSTANCE: 25,8 %

-BIODEGRADABILITY OF REFERENCE SUBSTANCE: 88,1%

-Blank control: 18,4 mg CO2/litre

The ThCO2 of the test sample after 28 days is 25.8% (average value of two replicates). Since the test sample biodegradation is < 60% ThCO2, the substance is considered not ready biodegradable.

Description of key information

The substance is considered not ready biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Additional information

OECD GUIDELINE Ready Biodegradability - 301 B: CO2 Evolution (Modified Sturm Test)

The ThCO2 of the test sample after 28 days is 25.8% (average value of two replicates). Since the test sample biodegradation is < 60% ThCO2, the substance is considered not ready biodegradable.