Mobam

If the compound has been ingested, rapid gastric lavage should be performed using 5% sodium bicarbonate. For skin contact, the skin should be washed with soap and water. If the compound has entered the eyes, they should be washed with large quantities of isotonic saline or water. In serious cases, atropine and/or pralidoxime should be administered. Anti-cholinergic drugs work to counteract the effects of excess acetylcholine and reactivate AChE. Atropine can be used as an antidote in conjunction with pralidoxime or other pyridinium oximes (such as trimedoxime or obidoxime), though the use of '-oximes' has been found to be of no benefit, or possibly harmful, in at least two meta-analyses. Atropine is a muscarinic antagonist, and thus blocks the action of acetylcholine peripherally.

Mobam was among carbamates effective in protecting guinea pigs against soman poisoning. Mobam raised the LD50 of soman by a factor of about 8.

Insecticidal and acaricidal effect of 4-benzothienyl n-methylcarbamate was synergistically enhanced by piperonyl butoxide, sulfoxide or MGK 264.

Acute exposure to cholinesterase inhibitors can cause a cholinergic crisis characterized by severe nausea/vomiting, salivation, sweating, bradycardia, hypotension, collapse, and convulsions. Increasing muscle weakness is a possibility and may result in death if respiratory muscles are involved. Accumulation of ACh at motor nerves causes overstimulation of nicotinic expression at the neuromuscular junction. When this occurs symptoms such as muscle weakness, fatigue, muscle cramps, fasciculation, and paralysis can be seen. When there is an accumulation of ACh at autonomic ganglia this causes overstimulation of nicotinic expression in the sympathetic system. Symptoms associated with this are hypertension, and hypoglycemia. Overstimulation of nicotinic acetylcholine receptors in the central nervous system, due to accumulation of ACh, results in anxiety, headache, convulsions, ataxia, depression of respiration and circulation, tremor, general weakness, and potentially coma. When there is expression of muscarinic overstimulation due to excess acetylcholine at muscarinic acetylcholine receptors symptoms of visual disturbances, tightness in chest, wheezing due to bronchoconstriction, increased bronchial secretions, increased salivation, lacrimation, sweating, peristalsis, and urination can occur. Chronically high (>10 years) exposure leads to neuropsychological consequences including disturbances in perception and visuo-motor processing (A15321).

LD50; Species: /Anas platyrynchos/ (Mallard) 12 month old male; oral 952 mg/kg (95% confidence limit 357-2535 mg/kg)

LD50;Species: /Tympanuchus phasianellus/ (Sharp-tailed Grouse) male; oral 173 mg/kg (95% confidence limit 99.9-300 mg/kg)

LD50; Species: /Callipepla californica/ (California Quail) 5-6 month old male; oral 463 mg/kg (95% confidence limit 266-805 mg/kg)

LD50; Species: /Coturnix japonica/ (Japanese Quail) 2 month old male; oral 668 mg/kg (95% confidence limit 530-842 mg/kg)

For more Ecotoxicity Values (Complete) data for MOBAM (9 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 195(SRC), determined from a structure estimation method(2), indicates that mobam is expected to have moderate mobility in soil(SRC). Volatilization of mobam from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.7X10-9 atm-cu m/mole(SRC), using a fragment constant estimation method(3). Mobam is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 5.3X10-5 mm Hg at 25 °C(SRC), determined from a fragment constant method(4). Mobam had a reported half-life of one to three months in the surface six inches of soil(5).

TERRESTRIAL FATE: .. The half life ... on soil ... is about 30 days ... on a variety of crops the half life is 6-7 days ...

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 195(SRC), determined from a structure estimation method(2), indicates that mobam 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 1.7X10-9 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). According to a classification scheme(5), an estimated BCF of 13(SRC), from an estimated log Kow of 2.17(6) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Mobam was reported to be stable to hydrolysis at pH 2, have a half-life of 8 days at pH 7 and a half-life of 0.5 days at pH 9(8). After one month in a model aquatic ecosystem, mobam was reported to have a low degree of biodegradability(9).

AQUATIC FATE: A model aquatic ecosystem was constructed in a 15-gallon glass aquarium and consisted of white quartz sand, "standard" reference water, sorghum (Sorghum halpense), salt marsh caterpillar (Estigmene acrea), water flea (Daphnia magna), mosquito larvae (Culex pipiens quinquefasciatus), algae (Oedogonium cardiacum), Physa snails, and mosquito fish (Gambusia affinis)(1). Radio-labeled mobam was reported to have a low degree of biodegradability after 30 days of exposure. Residual and parent materials concentration in water was 8 ppb, in mosquito larvae 154,000 ppb, and in fish 1100 ppb. Mobam was highly toxic to snails(2).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), mobam, which has an estimated vapor pressure of 5.3X10-5 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase mobam 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 10 hours(SRC), calculated from its rate constant of 3.5X10-11 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase mobam may be removed from the air by wet or dry deposition(SRC). Mobam contains chromophores that absorb at wavelengths >290 nm(4) and, therefore, may be susceptible to direct photolysis by sunlight(SRC).

Mobam is a cholinesterase or acetylcholinesterase (AChE) inhibitor. Carbamates form unstable complexes with chlolinesterases by carbamoylation of the active sites of the enzymes. This inhibition is reversible. A cholinesterase inhibitor suppresses the action of acetylcholine esterase. Because of its essential function, chemicals that interfere with the action of acetylcholine esterase are potent neurotoxins, causing excessive salivation and eye-watering in low doses. Headache, salivation, nausea, vomiting, abdominal pain and diarrhea are often prominent at higher levels of exposure. Acetylcholine esterase breaks down the neurotransmitter acetylcholine, which is released at nerve and muscle junctions, in order to allow the muscle or organ to relax. The result of acetylcholine esterase inhibition is that acetylcholine builds up and continues to act so that any nerve impulses are continually transmitted and muscle contractions do not stop.

/BIRDS and MAMMALS/ /Acute oral toxicity to birds had the following symptoms:/ asynergy, myasthenia, ataxia, imbalance, goose-stepping ataxia, stumbling or collapse, tremors, lacrimation, foamy salivation, diarrhea, tachypnea, dyspnea, loss of righting reflex, ataxia, tetany, tonic convulsions, clonic convulsions, wing-beat convulsions, and phonation.

As with organophosphates, the signs and symptoms are based on excessive cholinergic stimulation. Unlike organophosphate poisoning, carbamate poisonings tend to be of shorter duration because the inhibition of nervous tissue acetylcholinesterase is reversible, and carbamates are more rapidly metabolized. Muscle weakness, dizziness, sweating and slight body discomfort are commonly reported early symptoms. Headache, salivation, nausea, vomiting, abdominal pain and diarrhea are often prominent at higher levels of exposure. Contraction of the pupils with blurred vision, incoordination, muscle twitching and slurred speech have been reported. (L795)

Using a structure estimation method based on molecular connectivity indices(1), the Koc of mobam can be estimated to be 195(SRC). According to a classification scheme(2), this estimated Koc value suggests that mobam is expected to have moderate mobility in soil.

/SIGNS AND SYMPTOMS/ Nausea, vomiting, abdominal cramps, diarrhea & excessive salivation ... sweating. Lassitude & weakness. Rhinorrhea and sensation of tightness in chest may occur with inhalation exposure. Blurring or dimness of vision. Miosis ... tearing, ciliary muscle spasm, loss of accommodation and ocular pain. None of these ... signs ... is dependable for diagnosis. Mydriasis may be seen ... Loss of muscle coordination, slurring of speech, fasciculation & twitching of muscles. Difficulty in breathing, excessive secretions of saliva and of resp tract mucus, oronasal frothing, cyanosis, pulmonary rales & rhonchi, and hypertension. ... jerky movements, incontinence, convulsions and coma. Death ... due to resp arrest of central origin, paralysis of resp muscles, intense bronchoconstriction or all three. /Carbaryl/

/CASE REPORTS/ ... Some spraymen /working with MOBAM/ complained of skin irritation and other subjective symptoms that did not prevent continued work, and no rash or other signs were observed.