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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

Constituent 1
Chemical structure
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 productsopen allclose all
No.:
#1
Reference
Reference substance name:
Unnamed
IUPAC name:
N
Identity:
N
No.:
#2
Reference
Reference substance name:
Unnamed
IUPAC name:
NH4+
Identity:
NH4+
No.:
#3
Reference
Reference substance name:
Unnamed
IUPAC name:
NO2-
Identity:
NO2-
No.:
#4
Reference
Reference substance name:
Unnamed
IUPAC name:
NO3-N
Identity:
NO3-N
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

Applicant's summary and conclusion