Common name: Acephate
IUPAC name: O,S-dimethyl acetylphosphoramidothioate
Chemical Abstracts name: N-[methoxy(methylthio)phosphinoyl]acetamide
CAS RN:[30560-19-1]
PHYSICAL CHEMISTRY
Mol. wt.: 183.2
Form:Colourless crystals; (tech., a colourless solid)
M.p.: 88-90 ºC; (tech., 82-89 ºC)
V.p.: 0.226 mPa (24 ºC)
Kow logP= -0.89
S.g./density: 1.35
Solubility In water 790 g/l (20 ºC). In acetone 151, ethanol >100, ethyl acetate 35, benzene 16, hexane 0.1 (all in g/l, 20 ºC).
Stability Hydrolysis DT50 50 d (pH 5-7, 21℃), photodegradation DT50 (l = 253.7 nm) 55 h.
TOXICOLOGY
Oral Acute oral LD50 for male rats 1447, female rats 1030 mg/kg.
Skin and eye Acute percutaneous LD50 for rabbits >10 000 mg/kg. Slightly irritating to skin (rabbits); non-sensitising to skin (guinea pigs).
Inhalation LC50 (4 h) for rats >15 mg/l air.
NOEL (2 y) for dogs 0.75 mg/kg daily; LOEL for rats 0.25 mg/kg daily.
ADI (JMPR) 0.03 mg/kg
Toxicity class WHO (a.i.) III
EPA (formulation) III
EC hazard Xn; R22
ECOTOXICOLOGY
Birds Acute oral LD50 for mallard ducks 350, chickens 852, ring-necked pheasants 140 mg/kg.
Fish LC50 (96 h) for bluegill sunfish 2050, rainbow trout >1000, channel catfish 2230, largemouth black bass 1725 mg/l.
Daphnia EC50 (48 h) 67.2 mg/l; NOEC 43 mg/l.
Algae EC50 (72 h) >980 mg/l.
Other aquatic spp. LC50 (96 h) for crayfish 750 ppm.
Bees LD50 (contact) 1.2 mg/bee.
Worms LC50 (14 d) 22 974 mg/kg; NOEC 10 000 mg/kg.
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