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TRADE OR OTHER NAMES: Trade names for products containing formothion include Aflix, Anthio, Sandoz S-6900,
SAN 2441 and SAN 69131 (154, 138, 13).
REGULATORY STATUS: Formothion is a restricted use pesticide (RUP).
INTRODUCTION: Formothion is an organophosphate product. It is a systemic and contact insecticide used to control
spider mites, aphids, psyllids, mealy bugs, whiteflies, jassids, leaf miners, ermine moths, and fruit flies (154). It is used on
tree fruits, vines, olives, hops, cereals, sugar cane, rice (13). The U.S. EPA classifies formothion as toxicity class II -
moderately toxic. Products containing formothion bear the Signal Word "Warning." Formothion is available as an
emulsifiable concentrate and an ultra-low volume spray (112).
- Acute Toxicity: Formothion is a cholinesterase inhibitor which means it affects normal nervous system function. Early
symptoms of formothion poisoning include nausea or vomiting, dizziness, and weakness. Tightness in the chest and
difficulty breathing are common in inhalation exposure. As in other organophosphate poisonings, exposure may cause
blurred vision, muscle spasms, or loss of coordination (131). The LD50, the dose of formothion which kills half of the
test animals, is 365-500 mg/kg for rats; 410 - 420 mg/kg for rabbits; 102 mg/kg for mice; and 210 mg/kg for cats (126,
131). The LD50 is greater than 1,000 mg/kg for rats whose skin is exposed to formothion (154). The LC50 (4 hours),
the concentration in air which kills half of the test animals, is 4.5 mg/l air for rats. Formothion is non-irritating to skin.
- Chronic Toxicity: No Information Available.
- Teratogenic Effects: No evidence of teratogenic or embryotoxic effects was seen in rabbits given formothion from days
6 to 18 of pregnancy at rates of 6 and 30 mg/kg/day.(131)
- Reproductive Effects: No information is currently available.
- Mutagenic Effects: A number of studies on salmonella bacteria indicate that formothion is not mutagenic (155).
- Carcinogenic Effects: Formothion is an organophosphate pesticide. Studies indicate that organophosphate compounds
do not have structures resembling known carcinogens. Though no data is currently available on formothion, it is unlikely
that it causes cancer.
- Organ Toxicity: Cholinesterase is an enzyme critical to proper function of the nervous system. Formothion has been
found to inhibit the activity of cholinesterase, impairing normal nervous system functions (13, 131). Also, in rat feeding
studies, 16 mg/kg/day of formothion caused growth impairment in males during the first year of a two year study. It also
caused slight tremors and muscle spasms in individual rats during the same time period. Rats tended to recover during
the second year (131).
- Fate in Humans and Animals: Formothion is rapidly absorbed by the stomach of rats. It passes through the liver,
kidney, pancreas and thymus. Most (96%) of a dose of formothion is excreted within 24 hours. The majority of a dose
(98-99%) is excreted in urine and 2% in feces (131).
- Effects on Birds: Formothion is slightly toxic to birds. The oral LD50 for pigeons was 630 mg/kg (13).
- Effects on Aquatic Organisms: Formothion is slightly toxic to fish. The LC50 (96 hours) for carp is greater than 50
- Effects on Other Animals (Nontarget species): Formothion is toxic to bees (138).
- Breakdown of Chemical in Soil and Groundwater: Formothion is relatively non-persistent. The half-life of
formothion in loamy soils is one to 14 days (13, 131). There is no danger of formothion residues accumulating in soil,
even if plants are subject to repeated treatment (131).
- Breakdown of Chemical in Surface Water: No information is currently available.
- Breakdown of Chemical in Vegetation: In plants, formothion is metabolized rapidly and dissipates (13).
PHYSICAL PROPERTIES AND GUIDELINES
- Appearance: pale yellow, viscous liquid or crystalline mass. It is extremely stable to acids but decomposes on
distillation. It is incompatible with alkaline pesticides (131).
- Chemical Name: O,O-dimethyl dithiophos- phorylacetic acid N-methyl-N-formylamide
- CAS Number: 2540-82-1
- Molecular Weight: 257.3
- Water Solubility: 2.6 g / l
- Solubility in Other Solvents: Soluble in alcohols, ether, chloroform, ketones, and xylene (131)
- Melting Point: 25-26 degrees C (13).
- Vapor Pressure: 0.113 mPa (20 degrees C)
- Partition Coefficient:(octanol/water) ca. 30 (13)
- Adsorption Coefficient:Not Available
- ADI: 0.2 mg/kg (131)
- MCL: Not Available
- RfD: Not Available
- PEL: Not Available
- HA: Not Available
- TLV: Not Available
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References for the information in this PIP can be found in Reference List Number 5
DISCLAIMER: The information in this profile does not in any way replace or supersede the information on the pesticide
product label/ing or other regulatory requirements. Please refer to the pesticide product label/ing.