950-37-8 Usage
Uses
Used in Agriculture:
Methidathion is used as an insecticide to control a wide range of insects in many different crops, providing effective pest management and crop protection.
Used in Veterinary Medicine:
Methidathion is used as a topical treatment to reduce cattle lice infestation by 99.1% at a dose of 3.5 mg/kg. It is selectively toxic to lice over cattle, only inhibiting cattle plasma acetylcholinesterase activity by 20% with no effect on survival when administered topically at a dose of 24 mg/kg.
Used in Toxicological Research:
Methidathion has been examined for its toxicological effects on human health and animals. It has been found to increase sister chromatid exchange in a concentration-dependent manner, induce cell cycle arrest, and cause liver inflammation and cardiomyocyte damage in animal models. These studies contribute to understanding the potential risks and safety measures associated with the use of Methidathion.
Air & Water Reactions
Stable in neutral or weak acid solution. Hydrolyzed by alkali. [EPA, 1998].
Reactivity Profile
Organophosphates, such as Methidathion, are susceptible to formation of highly toxic and flammable phosphine gas in the presence of strong reducing agents such as hydrides. Partial oxidation by oxidizing agents may result in the release of toxic phosphorus oxides.
Hazard
Toxic by ingestion, a cholinesterase
inhibitor.
Health Hazard
Methidathion is poisonous to humans. Its toxic effects are by action on the nervous system. Human volunteers ingesting 0.11 mg/kg/day for 6 weeks had no clinical effects.
Health Hazard
Acute and prolonged exposures to methidathion cause poisoning in animals and humans. The symptoms include, but are not limited to, nausea, vomiting, cramps, diarrhea, salivation, headache, dizziness, muscle twitching, diffi culty breathing, blurred vision, and tightness in the chest, pulmonary edema, respiratory depression, and respiratory paralysis. Acute exposures to high concentrations of methidathion cause intense breathing problems, including paralysis of the respiratory muscles.
Fire Hazard
(Non-Specific -- Organophosphorus Pesticide, n.o.s.) Container may explode in heat of fire. Fire and runoff from fire control water may produce irritating or poisonous gases. Stable in neutral or weak acid solution. Hydrolyzed by alkali.
Trade name
CIBA-GEIGY? GS 13005?;
COBRACIDE?; FISONS NC? 2964; GEIGY? 13005; GS-13005?; SOMONIC?; SOMONIL?; SURPRACIDE?;
SUPRATHION?; ULTRACID?; ULTRACIDE?
Contact allergens
Methidation is an organophosphorus compound used as an insecticide. Cross-sensitivity was described to Dichlorvos.
Safety Profile
Poison by ingestion and
skin contact. Moderately toxic by inhalation.
Human mutation data reported. Human
systemic effects: coma, lachrymation, miosis.
A severe eye irritant. An insecticide. When
heated to decomposition it emits very toxic
fumes of NOx, POx, and SOx
Carcinogenicity
In a chronic toxicity/carcinogenicity study, rats were fed
diets with 0, 4, 40, or 100 ppm methidathion (equivalent to 0,
0.16, 1.72, or 4.91 mg/kg/day (males) and 0, 0.22, 2.20, or
6.93 mg/kg/day (females)) for 2 years, and there was no
evidence of carcinogenicity in either males or females .
Body weight decreases occurred in both sexes at the highest
dose throughout the study.
Environmental Fate
Photolytic. When methidathion in an aqueous buffer solution (25°C and pH 7.0) was
exposed to filtered UV light (l >290 nm) for 24 hours, 17% decomposed to 5-methoxy-
3H-1,3,4-thiadiazol-2-one. At 50°C, 56% was degraded after 24 hours. Degradation
occurred via hydrolysis of the thiol bond of the phosphorodithioic ester. Under acidic and
alkaline conditions, hydrolytic cleavage occurred at the C-S and P-S bonds, respectively
(Burkhard and Guth, 1979). Smith et al. (1978) demonstrated that methidathion degraded
to methidathion oxon at a faster rate in six air-dried soils than in moist soils. Half-lives
for methidathion in the air-dried soils ranged from 19 to 110 days. In addition, methidathion
degraded faster in an air-dried soil exposed to ozone (half-lives 2.5 to 7.0 days).Chemical/Physical. Emits toxic fumes of phosphorus, nitrogen and sulfur oxides when
heated to decomposition (Sax and Lewis, 1987). Methidathion oxon was also found in
fogwater collected near Parlier, CA (Glotfelty et al., 1990). It was suggested
Metabolic pathway
The main route of methidathion metabolism in animals and plants is via
hydrolysis or oxidation (or hydrolysis of the oxon) to yield the 3-
thiomethyl-5-methoxy-1,3,4-thiadiazoldee rivative. This may either lose
methanethiol to yield the methoxy-1,3,4thiadiazolinone or be conjugated
as the cysteine derivative via a route involving desmethylmethidathion
(in plants). In plants and mammals an additional route involves the
methylation of the thiomethyl methoxy-1,3,4-thiadiazolinone derivative
by S-adenosylmethionine followed by oxidation to the corresponding
sulfoxide and sulfone which are excreted in the urine in mammals.
Another route of detoxification in insects, plants and mammals is via
demethylation of the 5-methoxy group of the 1,3,4-thiadiazolinone ring
to form a metabolite which may be conjugated in plants. As is common
with many phosphorothioates, the active acetylcholinesterase inhibitor,
methidaoxon, is usually detected in metabolism studies but at very low
concentration due to its rapid rate of hydrolysis.
Metabolism
The principal degradation route is similar
both in animals and plants, that is, cleavage of the P?S
bond via oxidative desulfuration (activation) to the oxon
followed by hydrolysis to O,O-dimethyl hydrogen phosphorothioate
and the 3-thiomethyl-5-methoxythiadiazole
derivative, which is further degraded or conjugated.
Methidathion is rapidly degraded in soil; DT50 in soil
is 3–18 d.
Shipping
Color code—Blue: Health Hazard/Poison: Store in
a secure poison location. Prior to working with this chemical, personnel should be trained on its proper handling and
storage. Store in tightly closed containers in a cool, wellventilated area
Toxicity evaluation
The acute oral LD50 for rats is 25–54 mg/kg. Inhalation LC50
(4 h) for rats is 3.6 mg/L air. NOEL (2 yr) for rats is
4 mg/kg diet (0.2 mg/kg/d). ADI is 1 μg/kg b.w. Methidathion
administered to animals is rapidly metabolized
and excreted.
Degradation
Methidathion is rapidly hydrolysed in alkaline solution but it is relatively
stable in neutral and slightly acidic media. The DT50 for hydrolysis at pH
13 (25 °C) was 30 min (PM).
Waste Disposal
Treat with strong alkali, mix
with soil and bury in the case of small quantities.
For large quantities, use incineration with effluent gas
scrubbing
Precautions
Occupational workers should be very careful during use and chemical management of methidathion. As this chemical substance is a highly toxic pesticide, it has been grouped by the US EPA as toxicity class I. The containers and labels of the products should bear the signal word DANGER. Methidathion is an RUP, except for use in nurseries, and on saffl ower and sunfl owers.
Check Digit Verification of cas no
The CAS Registry Mumber 950-37-8 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 9,5 and 0 respectively; the second part has 2 digits, 3 and 7 respectively.
Calculate Digit Verification of CAS Registry Number 950-37:
(5*9)+(4*5)+(3*0)+(2*3)+(1*7)=78
78 % 10 = 8
So 950-37-8 is a valid CAS Registry Number.
InChI:InChI=1/C6H11N2O4PS3/c1-10-5-7-8(6(9)16-5)4-15-13(14,11-2)12-3/h4H2,1-3H3
950-37-8Relevant articles and documents
Macrocyclic plant acaricides
-
, (2008/06/13)
Compounds of the formula I STR1 in which either R is methyl and there is a double bond in the 9,10-position, or in which R is hydrogen and there is a single bond in the 9,10-position, are highly active against Acarina which damage plants.
Nitro- and cyanoguanidines as selective preemergence herbicides and plant defoliants
-
, (2008/06/13)
There are provided novel nitroguanidine and cyanoguanidine compounds. A method of dessicating and defoliating plants by applying to the foliage thereof certain nitroguanidine or cyanoguanidine compounds and a method for the selective preemergence control of undesirable broadleaf weeds and grasses in the presence of graminaceous crops are disclosed.
