title: Determination of methyl isocyanate in outdoor residential air near metam-sodium soil fumigations.
abstract: The soil fumigant metam-sodium (CH3NHCS2Na) produces the bioactive respiratory irritant methyl isothiocyanate (MITC). Recent laboratory gas-phase oxidative studies indicate that MITC rapidly transforms to the more toxic methyl isocyanate (MIC) in the lower atmosphere. Inhalation exposure risks from MITC plus MIC may therefore be an occupational worker and/or bystander health concern. To address this concern, MIC was monitored, along with MITC, in outdoor residential air in Washington state during the peak fall metam fumigation season. XAD-7 cartridges, coated with 1-(2-pyridyl)piperazine, were developed to retain MIC as its stable substituted urea derivative. Of the 68 residential air measurements of MIC, 15 (22%) were observed to be above the California Environmental Protection Agency's chronic inhalation reference level of 1 μg/m(3), with an observed maximum MIC air concentration of 4.4 μg/m(3). This study indicates MIC air concentrations can be anticipated along with MITC in residential air where seasonal metam soil fumigant applications occur.
authors.affiliation: Department of Natural Resources and Environmental Science, University of Nevada, Reno , 1664 North Virginia Street, Reno, Nevada 89557, United States.
authors.forename: James E
authors.initials: JE
authors.lastname: Woodrow
authors.forename: Jane T
authors.initials: JT
authors.lastname: LePage
authors.forename: Glenn C
authors.initials: GC
authors.lastname: Miller
authors.forename: Vincent R
authors.initials: VR
authors.lastname: Hebert
mesh_terms: D000180:Acrylic Resins; D016573:Agrochemicals / Q000008:administration & dosage; D000393:Air Pollutants / Q000032:analysis*; D002140:California; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods; D005651:Fumigation; D006801:Humans; D019570:Inhalation Exposure; D017953:Isocyanates / Q000032:analysis* / Q000737:chemistry; D008452:Maximum Allowable Concentration; D010575:Pesticides; D011137:Polystyrenes; D012621:Seasons; D012987:Soil / Q000737:chemistry*; D013859:Thiocarbamates / Q000008:administration & dosage / Q000032:analysis* / Q000737:chemistry; D014861:Washington
chemical_list: D000180:Acrylic Resins; D016573:Agrochemicals; D000393:Air Pollutants; D017953:Isocyanates; D010575:Pesticides; D011137:Polystyrenes; D012987:Soil; D013859:Thiocarbamates; C008435:methyldithiocarbamate; C015661:amberlite XAD 7; C008461:methyl isocyanate
keywords: air sampling; inhalation exposure; metam-sodium; methyl isocyanate; methyl isothiocyanate