L-Tyrosine, N-acetyl-3,5-diamino-O-(4-methoxyphenyl)-, ethyl ester

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

ethyl (2S)-3-[3,5-diamino-4-(4-methoxyphenoxy)phenyl]-2-acetamidopropanoate

Cas Number:

440667-78-7

Molecular formula:

C20H25N3O5

IUPAC Name:

ethyl (2S)-3-[3,5-diamino-4-(4-methoxyphenoxy)phenyl]-2-acetamidopropanoate

Test material form:

solid: particulate/powder

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, adapted

Details on inoculum:

Activated sludge from a biologic sewage treatment plant was used as inoculum. The cho-sen plant treats mostly domestic sewage.
The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, 67435 NW-Lachen-Speyerdorf.
Date of collection: 10. Jan. 2020, batch no: E20200110.
Pre-Treatment
The sludge was filtrated through a cloth, washed with test medium (2x) and re-suspended in test medium. It was then aerated until use. The dry matter was determined to contain 4.96 g of suspended solids/L.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

20 mg/L

Based on:

TOC

Details on study design:

Inoculum concentration: 25.0 mg/L
Temperature 17.8 – 22.1 °C without direct lighting
Duration 28 days

Reference substance

Reference substance:

aniline

Results and discussion

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

19

Sampling time:

28 d

Any other information on results incl. tables

Table 2 Degradation Values

In the following table, the percentage biodegradation is presented:

Table 8.3‑b      Degradation values in %

Day	Positive Control 1	Positive Control 2	Positive Control Mean	Test 1	Test 2	Test Mean	Abiotic Control	Toxicity Control
2	1.7	0.6	1.1	-0.4	5.1	2.3	0.5	0.7
4	5.0	11.7	8.3	1.7	6.4	4.0	1.2	16.5
7	39.6	57.4	48.5	6.1	10.3	8.2	1.5	44.9
9	64.5	65.7	65.1	6.9	10.9	8.9	1.5	45.5
11	74.4	73.9	74.1	6.5	10.1	8.3	1.5	47.7
14	81.5	80.4	80.9	5.9	10.7	8.3	1.6	48.1
18	78.6	81.4	80.0	7.2	12.8	10.0	1.6	49.7
23	82.7	83.9	83.3	8.3	13.0	10.7	1.7	51.5
29	93.0	91.8	92.4	15.0	22.5	18.8	0.9	58.4

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

• The test item L-Tyrosine, N-acetyl-3,5-diamino-O-(4-methoxyphenyl)-, ethyl ester is considered as “not readily biodegradable“.
• The degree of biodegradation reached 19 % at the end of the test duration.
• The 10-day-window began on day 18, at its end, 17 % degradation were reached, missing the pass level of 60 % given in the OECD guideline.
• Degradation missed 60 % within 28 days, too. Therefore, the test item is considered as “not ultimately biodegradable within 28 days”, as well.
• The abiotic degradation reached 0.9 %.

Executive summary:

All validity criteria were met.

Degradation behaviour of positive control and toxicity control was normal. Abiotic degradation reached 0.9 %. Both replicates of the test item showed good correspondence.

If degradation in the toxicity flask is below 25 % after 14 days, the test item can be considered as toxic towards the inoculum. As degradation in the toxicity flask was 48.1 % after 14 days, the test item can be stated as “not toxic towards the inoculum in a concentration of 32.9 mg/L”.

Ready biodegradability is defined in the guidelines as degradation surpassing 60% within 10 days after reaching a level of 10 %.

The 10-day-window began on day 18, at its end (day 28), 17 % degradation were reached, missing the pass level of 60 % given in the OECD guideline.

Therefore, the test item L-Tyrosine, N-acetyl-3,5-diamino-O-(4-methoxyphenyl)-, ethyl ester can be considered as “not readily biodegradable”.

On day 28, 5 mL HCl 2 M was added to each test flask in order to drive off dissolved CO₂. On day 29, samples from both scrubber flasks were taken.

Degradation missed the pass level of 60 % at the end of the test duration, though. Therefore, the test item is considered as “not ultimately biodegradable within 28 days”, as well.

No observations were made which might cause doubts concerning the validity of the study outcome.

The result of the test can be considered valid.