Vamidothion (ISO)

Colorless needles

White crystalline

Readily soluble in ... benzene, toluene, methyl ethyl ketone, ethyl acetate, acetonitrile, dichloromethane, cyclohexanone, chloroform (all at 1 kg/L). Almost insol in cyclohexane and petroleum ether.

In water, 4 kg/L at 20 °C /miscible/

Solubility in water: very good

43 °C

White waxy solid. Melting point ca 40 °C. /technical vamidothion/

46-48 °C

0.00000137 [mmHg]

Undergoes slight decomp at room temperature, but solutions in organic solvents (methyl ethyl ketone, cyclohexane) are stable. Decomposes in strong acid or alkaline media. VP: negligible at 20 °C.

negligible at room temperature

Colorless or white solid; [HSDB] Colorless solid; [MSDSonline]

COLOURLESS CRYSTALS.

Positive

3.33

2.7

Agilent XCT

Electrospray ionization

formic acid (5.3nM)

2036；2076.5；2075；2080；2083.8

2104.4；2103.2；2114.3；2116.4

Danger

H301: Toxic if swallowed [Danger Acute toxicity, oral]；H312: Harmful in contact with skin [Warning Acute toxicity, dermal]；H400: Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]

P264, P270, P273, P280, P301+P316, P302+P352, P317, P321, P330, P362+P364, P391, P405, and P501 (click each P-code to see the statement)

Danger

IMAP assessments - Phosphorothioic acid, O,O-dimethyl S-[2-[[1-methyl-2-(methylamino)-2-oxoethyl]thio]ethyl] ester: Environment tier I assessment；IMAP assessments - Phosphorothioic acid, O,O-dimethyl S-[2-[[1-methyl-2-(methylamino)-2-oxoethyl]thio]ethyl] ester: Human health tier I assessment

A cholinesterase inhibitor that may have nervous system effects causing convulsions and respiratory failure; Can be absorbed through skin; [ICSC] No adverse histopathological findings, increased tumors, or signs of developmental, delayed neurological, or teratogenic toxicity; [HSDB] The average of two baseline respective cholinesterase activity determinations three days apart, with no exposures to enzyme inhibiting pesticides for at least 30 days, is recommended for each worker prior to exposure to cholinesterase inhibitors because of large inter-individual differences in published baseline values. To be established at least once a year. Removal from workplace exposures is recommended until the cholinesterase activity returns to within 20% of baseline. [TLVs and BEIs]

/GUIDE 131: FLAMMABLE LIQUIDS-TOXIC/ Health: TOXIC; may be fatal if inhaled, ingested or absorbed through skin. Inhalation or contact with some of these materials will irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution. /Organophosphorus pesticide, liquid, flammable, poisonous; Organophosphorus pesticide, liquid, flammable, toxic; Organophosphorus pesticide, liquid, poisonous, flammable; Organophosphorus pesticide, liquid, toxic, flammable/

/GUIDE 131: FLAMMABLE LIQUIDS-TOXIC/ Fire or Explosion: HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion and poison hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water. /Organophosphorus pesticide, liquid, flammable, poisonous; Organophosphorus pesticide, liquid, flammable, toxic; Organophosphorus pesticide, liquid, poisonous, flammable; Organophosphorus pesticide, liquid, toxic, flammable/

/GUIDE 131: FLAMMABLE LIQUIDS-TOXIC/ Public Safety: CALL Emergency Response Telephone Number ... . As an immediate precautionary measure, isolate spill or leak area for at least 50 meters (150 feet) in all directions. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate closed spaces before entering. /Organophosphorus pesticide, liquid, flammable, poisonous; Organophosphorus pesticide, liquid, flammable, toxic; Organophosphorus pesticide, liquid, poisonous, flammable; Organophosphorus pesticide, liquid, toxic, flammable/

/GUIDE 131: FLAMMABLE LIQUIDS-TOXIC/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer. It may provide little or no thermal protection. Structural firefighters' protective clothing provides limited protection in fire situations ONLY; it is not effective in spill situations where direct contact with the substance is possible. /Organophosphorus pesticide, liquid, flammable, poisonous; Organophosphorus pesticide, liquid, flammable, toxic; Organophosphorus pesticide, liquid, poisonous, flammable; Organophosphorus pesticide, liquid, toxic, flammable/

For more DOT Emergency Guidelines (Complete) data for VAMIDOTHION (16 total), please visit the HSDB record page.

Acute Tox. 3 (100%)；Acute Tox. 4 (100%)；Aquatic Acute 1 (100%)

Acute toxicity (ingestion) - category 3；Acute toxicity (dermal) - category 4；Hazardous to the aquatic environment (acute) - category 1

Acute toxicity (Oral) - Category 3；Acute toxicity (Dermal) - Category 4；Acute toxicity (Inhalation: Dusts and mists) - Category 4；Specific target organ toxicity - Single exposure - Category 2 (nervous system)；Specific target organ toxicity - Repeated exposure - Category 1 (nervous system)

Self-reactive substances and mixtures - Type G；Acute toxicity (Oral) - Category 3；Acute toxicity (Dermal) - Category 4；Acute toxicity (Inhalation: Dusts and mists) - Category 4；Specific target organ toxicity - Single exposure - Category 2 (nervous system)；Specific target organ toxicity - Repeated exposure - Category 1 (nervous system)

Acute Tox. 3 *；Acute Tox. 4 *；Aquatic Acute 1

49 216 74; Organophosphorus pesticide, liquid, not otherwise specified (compounds and preparations) (insecticides, other than agricultural, NEC)

49 216 75; Organophosphorus pesticide, liquid, not otherwise specified (compounds and preparations) (agricultural insecticides, NEC, liquid)

49 105 44; Organophosphorus pesticide, liquid, not otherwise specified (compounds and preparations) (insecticides, other than agricultural, NEC)

49 105 45; Organophosphorus pesticide, liquid, not otherwise specified (compounds and preparations) (agricultural insecticides, NEC, liquid)

49 216 76; Organophosphorus pesticide, solid, not otherwise specified (compounds and preparations) (insecticides, other than agricultural, NEC)

49 216 77; Organophosphorus pesticide, solid, not otherwise specified (compounds and preparations) (agricultural insecticides, NEC, other than liquid)

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./

The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials.

The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.

Fresh air, rest. Half-upright position. Artificial respiration may be needed. Refer for medical attention.

Remove contaminated clothes. Rinse and then wash skin with water and soap. Refer for medical attention .

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth. Induce vomiting (ONLY IN CONSCIOUS PERSONS!). Refer for medical attention .

Biological Exposure Indices (BEI) [ACGIH] - Acetylcholinesterase activity in red blood cells = 70% of individual's baseline; Butylcholinesterase activity in serum or plasma = 60% of individual's baseline; Sample at end of shift; [TLVs and BEIs]

If material on fire or involved in fire: Do not extinguish fire unless flow can be stopped or safely confined. Use water in flooding quantities as fog. Solid streams of water may be ineffective. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Use "alcohol" foam, carbon dioxide or dry chemical. /Organophosphorus pesticides, liquid, NOS/

If material on fire or involved in fire: Use water in flooding quantities as fog. Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) Use foam, dry chemical. or carbon dioxide. /Organophosphorus pesticides, solid, NOS/

Environmental considerations: Land spill: Dig a pit, pong, lagoon, holding area to contain liquid or solid material. /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. Absorb bulk liquid with fly ash, cement powder, or commercial sorbents. /Organophosphorus pesticides, solid, NOS/

Environmental considerations: Water spill: use natural barriers or oil spill control booms to limit spill travel. Remove trapped material with suction hoses. /Organophosphorus pesticides, solid, NOS/

Environmental considerations: Air spill: Apply water spray or mist to knock down vapors. /Organophosphorus pesticides, solid, NOS/

Environmental considerations: Land spill: Dig a pit, pong, lagoon, holding area to contain liquid or solid material. /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. /Organophosphorus pesticides, liquid, NOS/

For more Cleanup Methods (Complete) data for VAMIDOTHION (6 total), please visit the HSDB record page.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting. Carefully collect remainder. Do NOT wash away into sewer. Then store and dispose of according to local regulations.

If material not on fire and not involved in fire: Keep sparks, flames, and other sources of ignition away. Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Attempt to stop leak if without undue personnel hazard. Use water spray to knock-down vapors. /Organophosphorus pesticides, liquid, NOS/

Personnel protection: Avoid breathing vapors. Keep upwind. ... Avoid bodily contact with the material. ... Do not handle broken packages unless wearing appropriate personal protective equipment. Wash away any material which may have contacted the body with copious amounts of water or soap and water. /Organophosphorus pesticides, liquid, NOS/

If material not on fire and not involved in fire: Keep sparks, flames, and other sources of ignition away. Keep material out of water sources and sewers. /Organophosphorus pesticides, solid, NOS/

Personnel protection: Avoid breathing dusts, and fumes from burning material. Keep upwind. ... Avoid bodily contact with the material. ... Do not handle broken packages unless wearing appropriate personal protective equipment. Wash away any material which may have contacted the body with copious amounts of water or soap and water. /Organophosphorus pesticides, solid, NOS/

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 810(SRC), determined from a structure estimation method(2), indicates that vamidothion is expected to have low mobility in soil(SRC). Volatilization of vamidothion from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 8.6X10-16 atm-cu m/mole(SRC), using a fragment constant estimation method(3). Vamidothion is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.4X10-6 mm Hg(SRC), determined from a fragment constant method(4). Vamidothion is expected to biodegrade in the environment based on an observed half-life of 1-1.5 days in soil at 22 °C(5).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 810(SRC), determined from a structure estimation method(2), indicates that vamidothon is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 8.6X10-16 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). According to a classification scheme(5), an estimated BCF of 3.2(SRC), from an estimated log Kow of 0.16(6) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Vamidothion is expected to biodegrade in the environment based on an observed half-life of 1-1.5 days in soil at 22 °C(8).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), vamidothion, which has an estimated vapor pressure of 1.4X10-6 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Vapor-phase vamidothion is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 2.8 days(SRC), calculated from its rate constant of 5.8X10-11 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase vamidothion may be removed from the air by wet or dry deposition(SRC). Vamidothion, present at a concn of 100 mg/L in distilled water with 2-4% methanol, degraded only 2% after 6 hours during an aqueous photolysis test which used a suntest apparatus consisting of a xenon arc lamp emitting 300-800 nm of light(4), suggesting that vamidothion is not susceptible to direct photolysis(SRC).

Pupillary constriction, muscle cramp, excessive salivation. Sweating. Nausea. Dizziness. Laboured breathing. Convulsions. Unconsciousness.

MAY BE ABSORBED! See Inhalation.

Abdominal cramps. Vomiting. Diarrhoea. Further see Inhalation.

Workers handling & applying pesticides must undergo an annual medical examination at the beginning of each agricultural season. Contraindications for work with /organophosphorus pesticides/ are organic diseases of the central nervous system, mental disorders & epilepsy, pronounced endocrine & vegetative disorders, pulmonary tuberculosis, bronchial asthma, chronic respiratory diseases, cardiovascular diseases & circulatory disorders, gastrointestinal diseases (peptic ulcer), gastroenterocolitis, diseases of liver & kidneys, eye diseases (chronic conjunctivitis & keratitis). The blood cholinesterase activity must be determined before work starts. In the event of prolonged work periods, this activity should be determined at intervals of 3-4 days. Persons exhibiting a fall in cholinesterase activity of 25% or more must be transferred to other work where they are not exposed to organophosphorus pesticides until this activity is completely restored. Persons with initial signs of indisposition should cease work with pesticides. /Organophosphorus pesticides/

A final diagnosis of mild to moderate acute organophosphate pesticide poisoning is rarely justified unless all of the following five conditions are present: 1. A definite history of exposure to an organophosphate pesticide. 2. A latent interval of not more than a few hours between that last exposure and the onset of illness. 3. A clinical picture in which most or all of the following signs or symptoms are present: headache, blurred vision, weakness, tightness in chest, and constricted pupils. 4. Reduction of plasma and RBC cholinesterase activity to a level substantially below 50% of baseline values. Because of the wide normal range of RBC cholinesterase in the population, symptoms may be present with reported "normal" levels. 5. An acute illness that is not substantially longer than 48 hours. The classic presentation for acute organophosphate toxicity includes history, evidence of exposure to organophosphate (garlic odor), signs/symptoms of cholinergic excess, improvement with atropine or pralidoxime, and inhibition of cholinesterase in blood. /Organophosphate pesticide poisoning/

Using a structure estimation method based on molecular connectivity indices(1), the Koc of vamidothion can be estimated to be 810(SRC). According to a classification scheme(2), this estimated Koc value suggests that vamidothion is expected to have low mobility in soil.

/HUMAN EXPOSURE STUDIES/ Eighteen people using vamidothion on crops were examined. The concentration of the product in air was 0.024 mg/cu m 50 meters away from the point of application. Symptoms recorded were a very slight drop in pulse rate and arterial blood pressure in 8 subjects. For 10 minutes, a reduction of 4-11% in blood cholinesterase was observed.

/SIGNS AND SYMPTOMS/ Organophosphate insecticides ... are potent cholinesterase enzyme inhibitors that act by interfering with the metabolism of acetylcholine, which results in accumulation of acetylcholine at neuroreceptor transmission sites. Exposure produces a broad spectrum of clinical effects indicative of massive overstimulation of the chlorinergic system, including muscarinic effects (parasympathetic), nicotinic effects (sympathetic and motor), and CNS effects. These effects present clinically as feeling of headache, weakness, dizziness, blurred vision, psychosis, respiratory difficulty, paralysis, convulsions, and coma. Typical findings are given by the mnemonic "SLUD." which stands for salivation, lacrimation, urination, and defecation. A small percentage of patients may fail to demonstrate miosis, a classic diagnostic hallmark. Onset of clinical manifestation of organophosphate poisoning usually occurs within 12 hours of exposure. /Organophosphate insecticides/

/SIGNS AND SYMPTOMS/ A follow up study of 232 people three years after a history of organophosphorus pesticide poisoning disclosed only one person with slight residual blurring of vision that might have been related to the earlier poisoning, though at the time of poisoning over one third of the people had blurring, which lasted only a day or two after exposure was discontinued. The possible exceptional case had findings suggestive of basilar artery insufficiency, rather than effects of poisoning. /Organophosphorus pesticide poisoning/

/SIGNS AND SYMPTOMS/ The duration of illness depends on the severity of poisoning, since several months may be required for cholinesterase activity to return to normal levels. Symptoms of mild to moderate organophosphate poisoning usually resolve by 1 month. A follow up study of pesticide workers who developed acute organophosphate poisoning revealed that episodes of headache, visual disturbances, nausea, and vomiting persisted 10 weeks after the acute episode, but the effect of reexposure to organophosphates could not be evaluated. /Organophosphate pesticide/

For more Human Toxicity Excerpts (Complete) data for VAMIDOTHION (11 total), please visit the HSDB record page.

Organophosphorus derivatives act by combining with and inactivating the enzyme acetylcholinesterase (AChE). ... The inactivation of cholinesterase by cholinesterase inhibitor pesticides allows the accumulation of large amounts of acetylcholine, with resultant widespread effects that may be ... separated into 4 categories: (1) Potentiation of postganglionic parasympathetic activity. ... (2) Persistent depolarization of skeletal muscle ... (3) Initial stimulation followed by depression of cells of central nervous system ... (4) Variable ganglionic stimulation or blockade ... /Cholinesterase inhibitor pesticides/

The main feature of the toxic mechanism of organophosphorus pesticides is inhibition of the esterase enzyme activity, in particular of cholinesterase, which plays an important physiological part. Organophosphorus pesticides can also indirectly interact with the biochemical receptors of acetylcholine. /Organophosphorus pesticides/

Plasma and tissue enzymes are responsible for hydrolysis /of organophosphorus cmpd/ to the corresponding phosphoric and phosphonic acids ... The cytochrome P450s are responsible for converting the inactive phosphorothioates containing a phosphorus sulfur (thiono) bond to phosphorates with a phosphorus-oxygen bond, resulting in their activation. These mixed-function oxidases also play a role in deactivation of certain organophosphorus agents. /Anticholinesterase agents/

These chemicals are detoxified by cytochrome p450-mediated monooxygenases in the liver, but some metabolites are more toxic than parent cmpd ... Metabolites usually are detected from 12 to 48 hr postexposure. /Organophosphate cmpd/

... Metabolized in plants to the corresponding sulfoxide which is of similar activity to vamidothion but of greater persistence.

In mammals and insects, demethylation and hydrolysis to phosphoric acid.

For more Metabolism/Metabolites (Complete) data for VAMIDOTHION (6 total), please visit the HSDB record page.

Most organophosphate compounds are ... absorbed from skin, conjunctiva, gastrointestinal tract, & lung. /Organophosphate compounds/

The rate of dermal absorption /of organophosphorus pesticides/ may be ... influenced by the solvent used. /Organophosphorus pesticides/

... The organophosphorus insecticides are, in contrast to the chlorinated insecticides, rapidly metabolized & excreted and are not appreciably stored in body tissues. /Organophosphorus insecticides/

Many of the organophosphorus insecticides are excreted in the milk ... /Organophosphorus insecticides/

For more Absorption, Distribution and Excretion (Complete) data for VAMIDOTHION (7 total), please visit the HSDB record page.

Used as systemic acaricide and insecticide for fruit trees, vines, ornamentals, beets, potatoes, cotton, rice, and other crops; Registered for use in many other countries; [HSDB]

No longer registered as a pesticide for use in the US; [HSDB] Banned in the EU for use as a biocide and agricultural insecticide; [eChemPortal: ESIS]

Farming (Pesticides) [Category: Industry]

Aphicide; miticide

It is a systemic acaricide and insecticide.

Used on fruit trees, vines, ornamentals, beet, potatoes, cotton, rice, etc for persistent control of all species of aphids (especially woolly aphids), thrips, sawfly larvae, psyllids, spider mites, etc.

Vamidothion is produced by reaction of O,O-dimethylphosphoric acid chloride with the sodium salt of N-methylcarbamylethylmercaptoethanethiol.

... 2-Chloroethanol (ethylene chlorohydrin) is reacted with ethyl 2-mercapto propionate giving ethyl-2-(2-hydroxyethylthio)propionate. That intermediate is, in turn treated successively with methylamine and thionyl chloride to give 2-(2-chloroethylthio)-N-methylpropionamide. Condensation with O,O-dimethylphosphorothioate gives vamidothion.

Emulsifiable solution.

Emulsifiable concentrate

Soluble concentrate (400 g ai/l)

The WHO Recommended Classification of Pesticides by Hazard identifies Vamidothion (technical grade) as Class IB: highly hazardous; Main Use: insecticide.

Not registered for use /in the United States/; Registered in many countries for cotton, hop, orchards, rice, sugarcane, vegetables, ornamentals; leafhoppers on rice.