title: Distribution and chemical fate of ³⁶Cl-chlorine dioxide gas during the fumigation of tomatoes and cantaloupe.
abstract: The distribution and chemical fate of (36)Cl-ClO2 gas subsequent to fumigation of tomatoes or cantaloupe was investigated as were major factors that affect the formation of chloroxyanion byproducts. Approximately 22% of the generated (36)Cl-ClO2 was present on fumigated tomatoes after a 2 h exposure to approximately 5 mg of (36)Cl-ClO2. A water rinse removed 14% of the radiochlorine while tomato homogenate contained ∼63% of the tomato radioactivity; 24% of the radiochlorine was present in the tomato stem scar area. Radioactivity in tomato homogenate consisted of (36)Cl-chloride (≥80%), (36)Cl-chlorate (5 to 19%), and perchlorate (0.5 to 1.4%). In cantaloupe, 55% of the generated (36)Cl-ClO2 was present on melons fumigated with 100 mg of (36)Cl-ClO2 for a 2 h period. Edible cantaloupe flesh contained no detectable radioactive residue (LOQ = 0.3 to 0.4 μg/g); >99.9% of radioactivity associated with cantaloupe was on the inedible rind, with <0.1% associated with the seed bed. Rind radioactivity was present as (36)Cl-chloride (∼86%), chlorate (∼13%), and perchlorate (∼0.6%). Absent from tomatoes and cantaloupe were (36)Cl-chlorite residues. Follow-up studies have shown that chlorate and perchlorate formation can be completely eliminated by protecting fumigation chambers from light sources.
authors.affiliation: Biosciences Research Laboratory, Agricultural Research Service, United States Department of Agriculture , 1605 Albrecht Boulevard, Fargo, North Dakota 58102-2765, United States.
authors.forename: D J
authors.initials: DJ
authors.lastname: Smith
authors.forename: W
authors.initials: W
authors.lastname: Ernst
authors.forename: J M
authors.initials: JM
authors.lastname: Giddings
mesh_terms: D002704:Chlorates / Q000032:analysis; D002713:Chlorine / Q000032:analysis; D017606:Chlorine Compounds / Q000032:analysis*; D028463:Cucumis melo / Q000737:chemistry* / Q000254:growth & development; D005651:Fumigation; D005740:Gases / Q000032:analysis; D007554:Isotopes / Q000032:analysis; D018551:Solanum lycopersicum / Q000737:chemistry* / Q000254:growth & development; D010087:Oxides / Q000032:analysis*; D010472:Perchlorates / Q000032:analysis
chemical_list: D002704:Chlorates; D017606:Chlorine Compounds; D005740:Gases; D007554:Isotopes; D010087:Oxides; D010472:Perchlorates; D002713:Chlorine; C025109:chlorine dioxide; C494474:perchlorate
keywords: cantaloupe; chlorate; chlorine dioxide; chloroxyanion; food safety; fumigation; perchlorate; tomato