2-methylpyridine

Biodegradation in soil

Administrative data

Endpoint:

biodegradation in soil

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: published in peer reviewed literature, minor restrictions in design and/or reporting but otherwise adequate for assessment

Data source

Reference

Reference Type:

publication

Title:

Degradation of Pyridine Derivatives in SoiI

Author:

Sims and Sommers

Year:

1985

Bibliographic source:

J. Environ. Qual., Vol. 14, na. 4, 1985

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

The test substance was incubated for 64 days in soil (Aeric Ochraqualfs) and the loss of parent compound determined by UV spectrometry. Accumulation of inorganle N released as a result of degradation was determined (colorimetry) to confirm decomposition of pyridine derivatives. Volatilization of the substance from soil was also measured.

GLP compliance:

not specified

Test type:

laboratory

Test material

Test material information

Constituent 1

Reference substance name:

2-methylpyridine

EC Number:

203-643-7

EC Name:

2-methylpyridine

Cas Number:

109-06-8

Molecular formula:

C6H7N

IUPAC Name:

2-methylpyridine

Details on test material:

- Name of test material: 2-methylpyridine

Radiolabelling:

no

Study design

Oxygen conditions:

aerobic

Soil classification:

other: Fincastle silt loam(aeric ochraqualfs)

Soil properties

Soil no.:

#1

Soil type:

silt loam

% Org. C:

1.2

pH:

6.7

CEC:

0.15 other: mol/kg

Details on soil characteristics:

PROPERTIES OF THE SOIL
- Soil-water ratio: 1:2
- Total N content: 1300 mg/kg
- Containing 0.25 kg H2O/ kg dry soil at -0.03 MPa

Duration of test (contact time)

Soil No.:

#1

Duration:

64 d

Initial test substance concentration

Soil No.:

#1

Initial conc.:

2 other: mmol/kg

Based on:

test mat.

Parameter followed for biodegradation estimation:

test mat. analysis

other: accumulation of inorganic Nitrogen

Experimental conditions

Soil No.:

#1

Temp.:

25 °C

Humidity:

-0.03 MPa

Details on experimental conditions:

PRELIMINARY EXPERIMENTS:
Preliminary experiments indicated that these foam stoppers retained 89-100% test substance volatilized from the solutions. Therefore, foam stoppers were used to retain volatilized compounds.
EXPERIMENTAL DESIGN
The soil was incubated treated with the test substance (2mmol/kg) in 100 mL glass vials at 25°C for 0-64 days. The soil was a Fincastle silt foam (Aeric Ochraqualfs) which had a pH of 6.7 (1:2 soil-water ratio), organic carbon content of 12 g/kg, total N content of 1300 mg/kg, CEC of 0.15 mol (+) /kg, and contained 0.25 kg H2O/kg dry soil at -0.03 MPa. Replicate experiments were prepared by adding 1.1 mL of H2O and 0.1 mL of the test substance solution to an incubation vessel and then adding 10g of soil carefully to preserve soil structure (final soil moisture was -0.03 MPa). The test solution contained 200 mmol/kg test substance dissolved in water and ethanol (2:1, v/v). The incubation vessels were adjusted for loss of 0.3 to 0.4 g H2). After 0, 1, 2, 4, 8, 16, 32, and 64 days of incubation, the foam stopper and soil from replicate containers were extracted separately and analyzed. Since processing of samples from each data required more than a day to complete, samples were stored at -20°C for a few days prior to extraction. To access the effects of storage on N content and recovery of the derivates of the test substance. A second set of replicate samples was taken at 0 days of incubation and stored at -20°C fot the duration of the experiment.

Results and discussion

Material (mass) balance

Soil No.:

#1

% Recovery:

0.5

Remarks on result:

other: After an incubation of 8 days

Transformation products:

yes

Identity of transformation products

Identity of transformation products 1

No.:

#1

Identity of transformation products 2

No.:

#2

Identity of transformation products 3

No.:

#3

Identity of transformation products 4

No.:

#4

Evaporation of parent compound:

yes

Volatile metabolites:

no

Residues:

yes

Details on results:

The test substance was not detected in the soil after 8 days of incubation. Accumulation of nitrogen confirmed the degradation of the test substance (see "any other information on result incl. tables"). Inorganic N did not accumulate in untreated soil which did not receive the test substance. Loss of test substance by volatilization was 5% or less. 2-3% of the test substance was recovered from the foam plugs.

Any other information on results incl. tables

Recovery of test substance from soil

	Recovery after incubation, d
	0*
Incubated in sterile soil for 7 d	NF	F	1	2	4	8	16	32	64
86.1	90.1	78.0	70.0	60.1	35.7	0.5	ND	ND	ND

*NF, Sample analyzed on day 0; F, sample frozen on day 0 and analyzed on day 64

ND = not detected

Accumulation of inorganic N in soil treated with test substance

Inorganic N* extracted after incubation time, d
0	16	32	64
Percent of degraded*
4.3	49.3	67.3	68.3

*Inorganic N, NH₄⁺, NO₂^-, and NO₃^--N