Difluoromethane

Toxicity to soil microorganisms

Administrative data

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Documentation insufficient for assessment

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

publication

Title:

Difluoromethane, a new and improved inhibitor of methanotrophy

Author:

Miller LG, Sasson C, Oremland RS

Year:

1998

Bibliographic source:

Applied and Environmental Microbiology 64:4357-4362

Materials and methods

Principles of method if other than guideline:

No data

Test material

Test material information

Constituent 1

Reference substance name:

Difluoromethane

EC Number:

200-839-4

EC Name:

Difluoromethane

Cas Number:

75-10-5

Molecular formula:

CH2F2

IUPAC Name:

difluoromethane

Details on test material:

No data

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
No data

Sampling and analysis

Details on sampling:

No data

Test substrate

Details on preparation and application of test substrate:

No data

Test conditions

Test temperature:

No data

Moisture:

No data

Details on test conditions:

No data

Nominal and measured concentrations:

No data

Results and discussion

Details on results:

No data

Results with reference substance (positive control):

No data

Reported statistics and error estimates:

No data

Any other information on results incl. tables

Abstract publication

Difluoromethane (HFC-32; DFM) is compared to acetylene and methyl fluoride as an inhibitor of methanotrophy in cultures and soils. DFM was found to be a reversible inhibitor of CH4 oxidation by Methylococcus capsulatus (Bath). Consumption of CH4 in soil was blocked by additions of low levels of DFM (0.03 kPa), and this inhibition was reversed by DFM removal. Although a small quantity of DFM was consumed during these incubations, its remaining concentration was sufficiently elevated to sustain inhibition. Methanogenesis in anaerobic soil slurries, including acetoclastic methanogenesis, was unaffected by levels of DFM which inhibit methanotrophy. Low levels of DFM (0.03 kPa) also inhibited nitrification and N2O production by soils. DFM is proposed as an improved inhibitor of CH4 oxidation over acetylene and/or methyl fluoride on the basis of its reversibility, its efficacy at low concentrations, its lack of inhibition of methanogenesis, and its low cost.

Applicant's summary and conclusion

Executive summary:

Abstract publication

Difluoromethane (HFC-32; DFM) is compared to acetylene and methyl fluoride as an inhibitor of methanotrophy in cultures and soils. DFM was found to be a reversible inhibitor of CH4 oxidation by Methylococcus capsulatus (Bath). Consumption of CH4 in soil was blocked by additions of low levels of DFM (0.03 kPa), and this inhibition was reversed by DFM removal. Although a small quantity of DFM was consumed during these incubations, its remaining concentration was sufficiently elevated to sustain inhibition. Methanogenesis in anaerobic soil slurries, including acetoclastic methanogenesis, was unaffected by levels of DFM which inhibit methanotrophy. Low levels of DFM (0.03 kPa) also inhibited nitrification and N2O production by soils. DFM is proposed as an improved inhibitor of CH4 oxidation over acetylene and/or methyl fluoride on the basis of its reversibility, its efficacy at low concentrations, its lack of inhibition of methanogenesis, and its low cost.