4-chloro-7H-pyrrolo[2,3-d]pyrimidine

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:

From January 25, 2021 to February 23, 2021

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

17th July 1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Batch number: 4419-190704
Purity: 99.3%

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): A fresh sample of activated sludge was collected from the aeration tank of Shenyang North Sewage Treatment Plant on the start day of the test.
- Preparation of inoculum for exposure: The inoculum was pretreated as follows: coarse particles were removed by filtration through a fine sieve and the sample was settled. After the supernatant was discarded, the sludge was washed twice with mineral medium and the concentrated sludge was suspended in mineral medium. 4 replicates of 10 mL suspended sludge was weighed and dried at 105oC for 1.5 hours and reweighed to calculate initial sludge concentration. The measured concentration of suspended sludge was 5.515 g/L as suspended solids (SS). The suspended sludge was prepared with mineral medium to yield a concentration of 4 g/L as suspended solids (SS) and keep the suspended sludge aerobic at 22.0oC ~ 23.5oC until the start of the test. On the day of the test 5 replicates of 10 mL suspended sludge was weighed and dried at 105C for 1.5 hours and reweighed to calculate initial sludge concentration. The measured concentration of suspended sludge was 3906 mg/L as suspended solids (SS).
- Initial cell/biomass concentration: 30 mg/L (as suspended solids (SS))

Duration of test (contact time):

28 d

Initial conc.:

89.72 mg/L

Based on:

test mat.

Details on study design:

TEST CONDITIONS
- Composition of medium: potassium dihydrogen orthophosphate, isodium hydrogen orthophosphate dihydrate, ammonium chloride, Calcium chloride dihydrate, magnesium sulfate heptahydrate, iron (III) chloride hexahydrate.
- Test temperature: 22oC±1oC
- Suspended solids concentration: 30 mg/L (as suspended solids (SS))
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 250 mL flask
- Number of culture flasks/concentration: 2 replicates
- Measuring equipment: Oxygen uptake was measured by BOD analyzer.

CONTROL AND BLANK SYSTEM
- Inoculum blank: Test vessels containing only 250 mL inoculated mineral medium were prepared in duplicate and served as inoculum controls.
- Toxicity control: Toxicity control test vessel contained both test item and reference item.

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Details on results:

Based on the percentage biodegradation expressed as average, the percentage biodegradation of test item after 28 days averaged 0.0% (2 replicates). The percentage degradation of the test item did not reach the pass level of 60% after 28 days of the test.

Results with reference substance:

Biodegradation of the reference substance (Sodium benzoate) reached 61.4% after 3 day and 17 hours, and was 78.1% after day 14, and 84.0% after day 28.

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The percentage biodegradation of test item after 28 days averaged 0.0% (2 replicates). The test item is not readily biodegradable under the described test conditions.

Executive summary:

The ready biodegradability test of the test item was conducted with unacclimatised sewage micro-organism by measuring oxygen consumption over a 28-day test period, according to OECD Guideline 301F under GLP.

The percentage biodegradation of test item after 28 days averaged 0.0% (2 replicates). The test item is not readily biodegradable under the described test conditions.

Description of key information

The ready biodegradability test of the test item was conducted with unacclimatised sewage micro-organism by measuring oxygen consumption over a 28-day test period, according to OECD Guideline 301F under GLP.

The percentage biodegradation of test item after 28 days averaged 0.0% (2 replicates). The test item is not readily biodegradable under the described test conditions.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater