3-methylpyrazole

Biodegradation in water and sediment: simulation tests

Administrative data

Endpoint:

biodegradation in water: simulation testing on ultimate degradation in surface water

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2021-05-31 - 2021-10-26

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 309 (Aerobic Mineralisation in Surface Water - Simulation Biodegradation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3-methylpyrazole

EC Number:

215-925-7

EC Name:

3-methylpyrazole

Cas Number:

1453-58-3

Molecular formula:

C4H6N2

IUPAC Name:

3-methyl-1H-pyrazole

Test material form:

liquid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

natural water / sediment

Details on source and properties of surface water:

Natural water from the pond “Kellmetschweiher” located near the town of Böhl-Iggelheim (49°21’52.268’’ N and 8°19’57.96’’E), Rhineland-Palatinate, Germany, was used. Water was sampled by the Test Facility on July 12, 2021. At the actual sampling site pH, oxygen, redox potential, conductivity and temperature of the water (and air) were determined prior to the sampling. The entire water volume was poured through a fine mesh (100 µm) in order to remove particles, soil, mesofauna and any plant parts (“pelagic test”). The sediment was sieved through a 2 mm sieve.

The journey from the sampling site to the test facility took 20 minutes. During this time, the samples were transported at room temperature. Further water characterisation was determined by the Test Facility and two contract laboratories. Aliquots of the natural water were directly shipped (under cooled conditions) after sampling to the contract laboratories Chemisches Institut Pforzheim and Städtisches Klinikum Karlsruhe for rapid determinations e.g. of nitrite and of colony forming units.

Upon arrival in the test facility, water was stored overnight at 4°C (± 2 °C) with aeration in the sample container. On July 13, 2021, aliquots of approximately 200 mL of the test water and 0.2 g sediment (dry weight) were weighed into the test vessels, transferred into the incubation chamber and pre-incubated at 20°C ± 2°C in the dark for one day. The test started on July 14, 2021 with application of the test systems.

Duration of test (contact time):

62 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

100 µg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

10 µg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

test mat. analysis

Reference substance

Reference substance:

other: Benzoic Acid [7-14C], ARC0186

Results and discussion

% Degradation

Parent/product:

product

Reference

Reference substance name:

Unnamed

IUPAC name:

3-methyl-1H-pyrazole

Inventory number:

InventoryMultipleMappingImpl [inventoryEntryValue=EC 215-925-7]

CAS number:

1453-58-3

Identity:

3-methylpyrazole

Identity:

3-methyl-1H-pyrazole

Molecular formula:

C4H6N2

Molecular weight:

82.104

SMILES notation:

Cc1cc[nH]n1

InChl:

InChI=1/C4H6N2/c1-4-2-3-5-6-4/h2-3H,1H3,(H,5,6)

Compartment:

water

Key result

% Degr.:

1.1

Parameter:

test mat. analysis

Sampling time:

62 d

Transformation products:

not measured

Results with reference substance:

As positive control for the microbial activity of natural water, radiolabelled benzoic acid was applied at a rate of 9.9 µg/L in test systems containing pure natural water. 14C-labelled Benzoic acid was completely degraded within 48 hours.

Any other information on results incl. tables

Amount of test item in % of applied in high dose test systems, transition 83.0>56.0 (quantifier)

 

Kellmetschweiher High dose (93.355 µg/L)		Incubation time [d]
[% applied]	Repetition		0	2	7	14	21	35	62
Water phase	a		102.6	103.2	102.6	102.2	100.8	101.9	98.5
	b		103.3	101.9	102.6	102.4	102.3	101.3	99.3
	mean		102.9	102.6	102.6	102.3	101.6	101.6	98.9

 

Amount of test item in % of applied in high dose test systems, transition 83.0>42.1 (qualifier)

 

Kellmetschweiher High dose (94.700 µg/L)		Incubation time [d]
[% applied]	Repetition		0	2	7	14	21	35	62
Water phase	a		100.9	101.8	100.5	99.9	100.1	99.9	97.3
	b		100.5	100.5	101.4	100.9	100.9	99.7	96.6
	mean		100.7	101.1	100.9	100.4	100.5	99.8	96.9

 

 

 Amount of test item in % of applied in low dose test systems, transition 83.0>56.0 (quantifier)

 

Kellmetschweiher Low dose (9.593 µg/L)		Incubation time [d]
[% applied]	Repetition		0	2	7	14	21	35	62
Water phase	a		100.4	87.0	88.8	88.3	85.4	84.0	81.9
	b		102.0	85.8	87.7	85.9	84.0	85.4	79.8
	mean		101.2	86.4	88.3	87.1	84.7	84.7	80.8

 

 

Amount of test item in % of applied in low dose test systems, transition 83.0>42.1 (qualifier)

 

Kellmetschweiher Low dose (9.662 µg/L)		Incubation time [d]
[% applied]	Repetition		0	2	7	14	21	35	62
Water phase	a		101.2	85.2	87.5	85.2	84.0	82.3	80.0
	b		99.2	85.6	87.0	84.9	82.5	84.6	77.9
	mean		100.2	85.4	87.2	85.1	83.2	83.4	79.0

 

 

 

 Amount of test item in % of applied in sterile control test systems, transition 83.0>56.0 (quantifier)

 

Kellmetschweiher Sterile control (93.355 µg/L)		Incubation time [d]
[% applied]	Repetition		14	62
Water phase	a		102.3	102.2
	b		104.2	104.4
	mean		103.3	103.3

 

 

 Amount of test item in % of applied in sterile control test systems, transition 83.0>42.1 (qualifier)

 

Kellmetschweiher Sterile control (94.700 µg/L)		Incubation time [d]
[% applied]	Repetition		14	62
Water phase	a		100.7	102.8
	b		103.6	100.5
	mean		102.2	101.7

 

 

 

Applicant's summary and conclusion

Validity criteria

Validity criteria fulfilled:

yes

Conclusions:

The microbial activity of freshly collected test water was shown by degradation and mineralisation of the reference substance 14C-benzoic acid.

After 62 days of incubation, no significant degradation of 3-Methylpyrazole was observed. 3 Methylpyrazole represented 98.9% and 80.8% AR in high dose and low dose test systems, respectively. Lower amounts of 3-Methylpyrazole in low dose test systems were in the same order of magnitude than recoveries in work-up controls and therefore mainly not caused by degradation.