KRESOXIM-METHYL

Details:

PHYSICAL CHEMISTRY
Mol. wt. 313.4  M.f. C18H19NO4  Form White, mildly aromatic crystals.  M.p. 101.6-102.5   B.p. decomp. 310   V.p. 2.3 ?10-3 mPa (20 )  KOW logP = 3.4 (pH 7, 25 )  Henry 3.6 ?10-4 Pa m3 mol-1  S.g./density 1.258 kg/l (20 )  Solubility In water 2 mg/l (20 ).  Stability Hydrolysis DT50 34 d (pH 7), 7 h (pH 9); relatively stable at pH 5.  pKa None in range 2-12 

MAMMALIAN TOXICOLOGY
Reviews FAO/WHO 83, 85 (see part 2 of the Bibliography).  Oral Acute oral LD50 for rats >5000 mg/kg.  Skin and eye Acute percutaneous LD50 for rats >2000 mg/kg. Non-irritating to skin and eyes (rabbits).  Inhalation LC50 (4 h) for rats >5.6 mg/l.  NOEL (3 mo) for male rats 2000 ppm (146 mg/kg daily), female rats 500 ppm (43 mg/kg daily).  ADI (JMPR) 0.4 mg/kg b.w. [1998].  Other Negative in the Ames test, and non-teratogenic.  EC classification R40| N; R50, R53 

ECOTOXICOLOGY
Although it is toxic to aquatic species, exposure tests and ecological studies have shown that there is no danger of permanent damage to aquatic organisms when kresoxim-methyl is used as recommended.  Birds LD50 (14 d) for quail >2150 mg/kg. LC50 (8 d) for bobwhite quail and mallard ducks >5000 ppm.  Fish LC50 (96 h) for bluegill sunfish 0.499 mg/l, rainbow trout 190 ppb.  Daphnia EC50 (48 h) 0.186 mg/l.  Algae EC50 (0-72 h) 63 mg/l.  Bees LD50 (48 h) (contact) >20 mg/bee.  Worms LC50 >937 mg/kg. 

ENVIRONMENTAL FATE
Animals Orally administered test compound was widely distributed and quickly eliminated; there was no bioaccumulation. The major routes of excretion were faeces and urine. Thirty two different metabolites were identified.  Plants Residues in cereals and pome fruit at harvest are <0.05 mg/kg, in grapes and vegetables <1 mg/kg.  Soil/Environment Rapidly degraded; in aerobic soil, or under aerobic or anaerobic aquatic metabolism, DT50 <1 d. In soil, DT90 (lab.) <3 d; the main metabolite is the corresponding acid. Very mobile in soil; Koc 219-372; Koc of the acid 17-24. However, in lysimeter studies, only low levels of kresoxim-methyl and its metabolite were found in leachates (R. Becker-Arnold & R. T. Hamm, Proc. 9th IUPAC Int. Congr. Pestic. Chem., London, 1998, 2, 6D-017).