IDENTIFICATION
Common name: Endosulfan
Iupac name: (1,4,5,6,7,7-hexachloro-8,9,10-trinorborn-5-en-2,3-ylenebismethlene) sulfite;
Type: Insecticide for Agriculture
CAS RN: [115-29-7] endosulfan; [959-98-8] formerly [33213-66-0], alpha-endosulfan; [33213-65-9] formerly [891-86-1] and [196070-15-6], beta-endosulfan
M.F.: C9H6Cl6O3 S
Mol Wt: 406.9
PHYSICAL CHEMISTRY
Form (appearance): Endosulfan is a mixture of two stereoisomers: alpha-endosulfan, endosulfan(Ⅰ), stereochemistry 3α,5aβ,6α,9α, 9aβ-, comprises 64-67% of the tech. grade; beta-endosulfan, endosulfan (Ⅱ), stereochemistry 3α,5aα,6β,9β, 9aα-, 29-32%. Earlier reports on the stereochemistry of these isomers gave conflicting reports (W.Riemschneider, World Rev. Pest control, 1963,2(4),29).
Colorless crystals; (tech., cream to brown, mostly beige)
M.P.: ≥80℃(tech.);α- 109.2℃;β-213.3℃
V.P.: 0.83mPa (20℃) for 2:1 mixture ofα-and β- isomers
S.G.: c.1.8 (20℃)( tech.)
Solubility: In water alpha-endosulfan 0.32, beta-endosulfan 0.33,(both in mg/l 22℃). In ethyl acetate, dichloromethane, toluene 200, ethanol c.65, hexane c.24 (all in g/l, 20℃).
Stability: Stable to sunlight, slowly hydrolysed in aqueous acids and alklalis, with the formation of the diol and sulfur dioxide.
Henry: α-1.48;β-0.07 (both Pa m3 mol-1, 22℃,calc.)
KowlogP: for α- =4.74; β- =4.79 (both at pH 5)
APPLICATION
Formulation types: DP;EC;GR;UL;SC;WP; Powder concentrate.
Biochemistry: Antagonist of the GABA receptor-chloride channel complex.
Mode of action: Non-systemic insecticide and acarcide with contact and stomach action.
Uses: Control of sucking, chewing, and boring insects and mites on a very wide range of crops, including fruit (including citrus), vines (0.1-0.2%), olives, vegetables including potatoes (0.1-0.2%),ornamentals, cucurbits, cotton (1.5-2.5 l/ha), tea (1.0-2.0 l/ha), coffee (1.5-2.0 l/ha), rice (1.5-2.0 l/ha), cereals (1.0-2.0 l/ha), maize and sorghum (1.5-2.5 l/ha), oilseed crops (1.0-2.0 l/ha), hops, hazels, sugar cane (1.5-2.5 l/ha), tobacco (0.8-1.5 l/ha), alfalfa, mushrooms, forestry, glasshouse crops, etc. Also controls tsetse flies.
Phytotoxicity: Glasshouse geraniums and chrysanthemums, alfalfa, and lima beans may be injured.
Compatibility: Incompatible with strongly alkaline materials.
MAMMALIAN TOXICOLOGY
Oral: Acute oral LD50 for rats 70 mg (in aqueous suspension)/kg, 110 mg tech. (in oil)/kg, 76 mg alpha- isomer/kg, 240 g beta- isomer/kg; for dogs 77 mg tech./kg.
Skin and eye: Acute percutaneous LD50 for rabbits 359 mg (in oil)/kg; for male rats >4000, female rats 500 mg/kg.
Inhalation: LC50 (4 h) for male rats 0.0345, female rats 0.0126 mg/l.
Noel: (2 y) for rats 15 ppm diet; (1 y) for dogs 10 ppm diet.
ADI: (JMPR) 0.006 mg/kg b.w. [1998].
Toxicity: WHO (a.i.) II; EPA (formulation) I (tech.)
EC hazard: T; R24/25| Xi; R36| N; R50, R53
ECOTOXICOLOGY
Birds: Acute oral LD50 for mallard ducks 205-245, ring-necked pheasants 620-1000 mg/kg.
Fish: Highly toxic (LC50 (96 h) for golden orfe 0.002 mg/l water) but, in practical use, should be harmless to wildlife.
Daphnia: LC50 (48 h) 75-750 μg/l.
Algae: EC50 (72 h) for green algae >0,56 mg/l.
Worms: NOEC 0.1 mg/kg dry weight.
Bees: Not toxic to bees under field conditions at an application rate of 1.6 l/ha (560 g endosulfan/ha).
ENVIRONMENTAL FATE
The plant metabolites (mainly endosulfan sulfate) were also found in animals and have thus been investigated from a toxicological point of view. 50% of residues are lost in 3-7 days (depending on plant species).
Animals: The principal route of elimination is faeces; most of the radioactivity is excreted within the first 48 hours. The amounts excreted are independent of dose level, number of dosages and isomerism. There are indications of species-specificity. Residues of endosulfan accumulate in the kidneys rather than in fat. Elimination from the kidneys takes place with DT50 7 d. but there is no sign of accumulation in the kidneys even after long-term feeding. Endosulfan is metabolised rapidly in mammalian organisms to less-toxic metabotites and to polar conjugates.
Soil/Environment: Endosulfan (alpha-and beta-) is degraded in soil with DT50 30-70 d. The main metabolite usually found was endosulfan sulfate, which is degraded more slowly and is, for this reason, the most important metabolite, DT50 for total endosulfan (alpha- and beta- endosulfan and endosulfan sulfate) in the field is 5-8 mo. No leaching tendency was observed. Koc 3000-20000; Kd <3%. |
