2-amino-5-(2-hydroxyethyl)-6-methyl-4(3H)-pyrimidinone

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:

Sept 2017 - March 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)

Deviations:

yes

Remarks:

Temperature range was 19.4 – 22.2 °C instead of 20.0 – 24.0 °C. As degradation of the positive control was in the normal range, this is considered as uncritical concerning the outcome of the study.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material:
- Expiration date of the lot/batch: 1 February 2019

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room Temperature (20 ± 5°C)
- Stability under test conditions: Stable
- Solubility and stability of the test substance in the solvent/vehicle: H2O: 1.58 g/L
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: n.a.

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: None
- Final dilution of a dissolved solid, stock liquid or gel: The test item was tested using a nominal concentration of 40 mg organic carbon/L in test medium.SOURCE OF TEST MATERIAL

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure):
- Pretreatment: The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf.
Date of collection: 10. Oct. 2017, batch no: 20171010. The sludge was filtrated through a clean cotton cloth, then washed with tap water twice, with test medium once and resuspended in test medium. It was then aerated until use in the test. Determination of dry matter gave 4840 mg suspended solids/L.
-Inoculum concentration: 25.0 mg dry matter/L

Duration of test (contact time):

28 d

Initial conc.:

40 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: As descried in test guideline
- Test temperature: 19.4 – 21.5 °C
- pH: 7.3 – 7.5
- pH adjusted: yes
- Continuous darkness: yes

TEST SYSTEM
Flask volume 250 mL
Controls 2, containing mineral medium and inoculum
Positive control flasks 2, containing positive control, mineral medium and inoculum
Test flasks 2, containing test item, mineral medium and inoculum
Abiotic control 1, containing test item, mineral medium and HgCl2
Adsorption control 1, containing test item, mineral medium, inoculum and HgCl2
Toxicity control 1, containing test item, positive control, mineral medium and inoculum
The test was performed with a start concentration of 40.2 mg dissolved organic carbon/L of test item and 40.1 mg dissolved organic carbon/L of positive control.

SAMPLING
- Sampling frequency: 8 samples were taken in order to determine the DOC (after 3 hours and on days 3, 7, 9, 14, 17, 23 and 28)

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: yes
- Toxicity control: yes

Reference substance:

aniline

Preliminary study:

None.

Key result

Parameter:

% degradation (DOC removal)

Value:

ca. 1

Sampling time:

28 d

Remarks on result:

other: Not readily biodegradable

Details on results:

- The 10-day-window was not detected.
- The degree of biodegradation reached 1 % after 28 days.
- The test item can be considered as „not readily biodegradable“.

- The difference within replicates at the end of the test was 0.3 % (criterion: <= 20%).
- The positive control reached 97 % on day 7 (criterion: > 70% within 14 days).
- The total biodegradation in the toxicity control after 14 days was 50 % (criterion: > 35 %).

Degradation behaviour the positive control was normal.

If degradation in the toxicity flask is below 35 % after 14 days, the test item can be considered as toxic towards the inoculum. As degradation in the toxicity flask was 50 % after 14 days, the test item can be stated as “not toxic towards the inoculum in a concentration of 80.2 mg/L”

DOC elimination could be observed also in the abiotic control and the adsorption control. Abiotic degradation reached 76 % and adsorption control reached 63 % degradation at the end of the test. The reason for this is most likely the precipitation of dissolved test item in the presence of Mercury(II)chloride.

The 10-day-window was not detected. Therefore, when applying the 10-day-window, the test itemSP02 (trade name: 5OHMlC) is not readily biodegradable following OECD 301A/EU C.4-A.

The validity criteria were met. No observations showing inconsistencies of the test data were made.

The result of the test can be considered valid.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The degree of biodegradation reached 1 % after 28 days. The 10-day-window was not detected. Therefore, when applying the 10-day-window, the test item SP02 (trade name: 5OHMlC) is not readily biodegradable following OECD 301A/EU C.4-A.

Executive summary:

The degree of biodegradation reached 1 % after 28 days. The 10-day-window was not detected. Therefore, when applying the 10-day-window, the test item SP02 (trade name: 5OHMlC) is not readily biodegradable following OECD 301A/EU C.4-A.

Description of key information

The degree of biodegradation reached 1 % after 28 days.

Degradation behaviour the positive control was normal.

If degradation in the toxicity flask is below 35 % after 14 days, the test item can be considered as toxic towards the inoculum. As degradation in the toxicity control was 50 % after 14 days, the test item can be stated as “not toxic towards the inoculum in a concentration of 80.2 mg/L”

DOC elimination could be observed also in the abiotic control and the adsorption control. Abiotic degradation reached 76 % and adsorption control reached 63 % degradation at the end of the test. The reason for this is most likely the precipitation of dissolved test item in the presence of Mercury(II)chloride.

The 10-day-window was not detected. Therefore, when applying the 10-day-window, the test item SP02 (trade name: 5OHMlC) is not readily biodegradable following OECD 301A/EU C.4-A.

The validity criteria were met. No observations showing inconsistencies of the test data were made.

The result of the test can be considered valid.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater