3-phenyl-1H-pyrazole-4-carbaldehyde

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

31 MAR 2021 to 28 APR 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2022

Report date:

2022

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

July 1992

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: MEP, P.R. China, the Guideline for the Testing of Chemicals, Degradation adn Accumulation, No.301F

Version / remarks:

2013.9

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: OECD Guidelines for the Testing of Chemicals, Revised Introduction to the OECD Guidelines for Testing of Chemicals, Section 3

Version / remarks:

March 2006

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3-phenyl-1H-pyrazole-4-carbaldehyde

EC Number:

632-673-7

Cas Number:

26033-20-5

Molecular formula:

C10H8N2O

IUPAC Name:

3-phenyl-1H-pyrazole-4-carbaldehyde

Test material form:

solid: particulate/powder

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source: domestic wastewater treatment plant, Shenyang North Sewage Treatment Plant, China.
- Preparation of inoculum for exposure:
On the day of sludge collection, 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. Four replicates of 10 mL suspended sludge were weighed and dried at 105 °C for 1 hour and 30 minutes and reweighed to calculate initial sludge concentration. The measured concentration of suspended sludge was 6.675 g/L as suspended solids (SS). The suspended sludge was prepared with mineral medium to yield a concentration of 4.0 g/L as SS. The suspended sludge was kept at 22.1 - 23.3°C, under aerobic conditions until the start of the test. On the day of the start of the test, five replicates of 10 mL sludge were weighed and dried at 105 °C for 2 hours and reweighed. The measured concentration was 4.112 g/L as SS. From this result, the added amount of wet sludge was calculated.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

28.2 mg/L

Based on:

test mat.

Remarks:

equivalent to 52.4 mg/L as ThODNH3

Initial test substance concentration 2

Initial conc.:

29.6 mg/L

Based on:

test mat.

Remarks:

equivalent to 55.0 mg/L ThODNH3

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: test water prepared according to test guidelines.
- The stock solutions were prepared as follows using analytical grade reagents, except that Na2HPO4·2H2O was HPLC grade.
(A) 4.2503 g potassium dihydrogen orthophosphate (KH2PO4), 10.8756 g dipotassium hydrogen orthophosphate (K2HPO4), 16.7011 g disodium hydrogen orthophosphate dihydrate (Na2HPO4·2H2O) and 0.2501 g ammonium chloride (NH4Cl) in distilled water and make up to 500 mL. The pH of the solution was 7.83 and adjusted to 7.58 with HCl.
(B) 3.6403 g calcium chloride dihydrate, CaCl2·2H2O in distilled water and make up to 100 mL.
(C) 2.2505 g magnesium sulfate heptahydrate (MgSO4·7H2O) in distilled water and make up to 100 mL.
(D) 0.0250 g iron (III) chloride hexahydrate (FeCl3·6H2O) in distilled water and make up to 100 mL.
* For 1 liter of mineral medium, 10 mL stock solution A was added to approximately 800 mL distilled water and the mixture stirred before adding, sequentially, 1 mL each of stock solutions B, C and D. After mixing, the mixture was made up to 1 liter with distilled water. The pH of the minral medium was 7.50.
- Additional substrate: no

TEST SYSTEM
Respirometer system preparation: the reference pressure vessel was tightened, the electrolyte bottle was filled with 45 mL of 25% (w/v) CuSO4.5H2O solution and 2-3 g CuO and the electrolyte bottle was fitted into the probe housing and tightened. After the test flasks were prepared, as soon as possible, the magnetic stirring rod was added to the flasks, CO2 trap cuvette was filled with 4 mL of 10 mol/L NaOH solution and was pushed on to the sensor head. The test flasks were attached to the sensor head. The sample flasks were immersed in the constant temperature water bath (22 °C ± 1 °C). The stirring and the measurement of BOD values were started. Oxygen uptake values in all test flasks were recorded every at 24 hours during the 28 day period by the automated respirometer. Incubation temperature was measured continuously with minimum/maximum thermometer and the minimum and maximum values were recorded on every working day during the test, the measured range was 22.0 ~ 22.8 °C. In addition, the magnetic stirrer was checked on every working day to determine proper operation.

SAMPLING
- Sampling frequency: every day during 28 days

CONTROL AND BLANK SYSTEM
- Biotic control: yes, two replicates with inoculum
- Abiotic sterile control: yes
- Toxicity control: no
- Procedure control: yes, 1 replicate with reference substance and inoculum

Reference substance

Reference substance:

benzoic acid, sodium salt

Remarks:

sodium benzoate

Results and discussion

Test performance:

The positive control item was biodegraded by at least 60% within 14 days, confirming suitability of the activated sludge.

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

28 d

Remarks on result:

other: average biodegradation of test item after 28 days (2 replicates).

Details on results:

The biodegradation of test item in Test Suspension 1 (TS-1) after 28 days was 0.4%, the biodegradation of test item in Test Suspension 2 (TS-2) after 28 days was 1.5%

BOD5 / COD results

Results with reference substance:

The biodegradation of the reference substance (Sodium benzoate) was 86.8% after Day 14 and 93.8% after Day 28.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

This study determined the ready biodegradability of T003897 in a 28-day manometric respirometry test according to OECD guideline 301F in the presence of activated sludge (30 mg SS/L) from a waste water treatment plant treating mainly domestic sewage. Based on the results, the percentage biodegradation of T003897 within 28 days did not exceed the pass level of 60% biodegradation, based on ThOD. The test item did not meet the criteria for “ready biodegradability” under the described test conditions