Specification :

Thiabendazole

Common name: thiabendazole
IUPAC name: 2-( thiazol-4-yl) benzimidazole; 2-( 1, 3-thiazol-4-yl) benzimidazole
Chemical Abstracts name: 2-( 4-thiazolyl) -1H-benzimidazole
CAS RN: [ 148-79-8]

PHYSICAL CHEMISTRY
Mol. wt.: 201.3; M.f.: C10H7N3S; Form: Off-white powder. M.p.: 297-298 ° C. V.p.: 4.6x10-4 mPa ( 25 ° C) . KOW: logP = 2.39 ( pH 7) . Henry: 2.7x10-8 Pa m3 mol-1 S.g./ density: 1.3989; Solubility: In water 0.16 ( pH 4) , 0.03 ( pH 7) , 0.03 ( pH 10) ( all in g/ l, 20 º C) . In n-heptane 2000 mg/ kg. Non-irritating to eyes and skin ( rabbits) . Not a skin sensitiser ( guinea pigs) .
Inhalation: LC50 for rats > 0.5 mg/ kg.
NOEL: In 2 y feeding trials, rats receiving 40 mg/ kg daily showed no ill-effects.
ADI: 0.1 mg/ kg b.w.
Toxicity class: WHO ( a.i.) III ( Table 5) ; EPA ( formulation) III

ECOTOXICOLOGY
Birds: Acute oral LD50 for bobwhite quail > 2250 mg/ kg. Dietary LC50 ( 5 d) for bobwhite quail and mallard ducks > 5620 mg/ kg diet.
Fish: LC50 ( 96 h) for bluegill sunfish 19, rainbow trout 0.55 mg/ l.
Daphnia: EC50 ( 48 h) 0.81 mg/ l.
Algae: EC50 ( 96 h) for Selenastrum 9 mg/ l; NOEC for Selenastrum 3.2 mg/ l.
Other aquatic spp.: LC50 ( 96 h) for shrimps 0.34 mg/ l, oysters > 0.26 mg/ l.
Bees: Not toxic to bees.
Worms: LC50 > 500 mg/ kg soil.

ENVIRONMENTAL FATE
Animals: When administered orally, thiabendazole is rapidly absorbed; up to 90% of the total dose is eliminated ( about 65% in urine and 25% in faeces) within 24 h, in both sexes. The compound is rapidly distributed to tissues, with highest levels found in the heart, lungs, spleen, kidneys, and liver. The compound is essentially completely cleared from the body within 7 days in both dose groups. Thiabendazole undergoes hydroxylation at the 5-position.
Plants: The residue on all crops treated pre- or post-harvest is parent thiabendazole.
Soil/ Environment: Soil DT50 33 d ( 20 ° C, 40% MWC, 0.1 mg a.i./ kg soil) , 120 d ( 20 ° C, 40% MWC, 1 mg a.i./ kg soil) . Aqueous photolysis DT50 29 h ( pH 5) .