化合物详情

Pesticide Ecotoxicity Data from EPA: 28

USDA APHIS Chemical Effects: collection=usda_chemeffect&query_type=synonym&query='^2686-99-9$'

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), trimethacarb, which has a vapor pressure of 5.1X10-5 mm Hg at 25 °C(2), is expected to exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase 2,3,5-trimethacarb 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 18 hours(SRC), calculated from its rate constant of 2.1X10-11 cu cm/molecule-sec at 25 °C (SRC) determined using a structure estimation method(3). Particulate-phase 2,3,5-trimethacarb may be removed from the air by wet and dry deposition(SRC).

The Koc of 2,3,5-trimethacarb is estimated as 470(SRC), using a measured water solubility of 58 mg/l(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that 2,3,5-trimethacarb is expected to have moderate mobility in soil(SRC).

2,3,5-Trimethacarb was degraded 15% in a pristine Drummer-Catlin soil mixture over a 2 week incubation period(1). However when the soil was pre-treated with carbofuran (1 application of 5 ug/g of carbofuran and incubated for 42 days) the amount biodegraded was 34% and when pre-treated with trimethacarb (2,3,5- and 3,4,5-isomers) the amount biodegraded was 75% over a 2 week period(1). After 42 days roughly 50% of the added 2,3,5-trimethacarb had been degraded from the pristine soil, while over 90% had been degraded in the treated soils(1). It was also observed that the rate of biodegradation was slightly greater for 3,4,5-trimethacarb when compared to 2,3,5-trimethacarb(1). Methyl carbamate and phenyl carbamate insecticides such as carbaryl, carbofuran, propoxur, propham, and phenmedipha...

An estimated BCF of 60 was calculated for 2,3,5-trimethacarb(SRC), using a water solubility of 58 mg/l(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is moderate(SRC).

The Henry's Law constant for 2,3,5-trimethacarb is estimated as 2.2X10-7 atm-cu m/mole(SRC) based upon trimethacarb's vapor pressure, 5.1X10-5 mm Hg(1), and water solubility, 58 mg/l(1). This Henry's Law constant indicates that 2,3,5-trimethacarb is not expected to volatilize from water surfaces(2). 2,3,5-Trimethacarb's estimated Henry's Law constant(1,2) indicates that volatilization from moist soil surfaces is not expected to be an important fate process(SRC). 2,3,5-Trimethacarb is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).

The rate constant for the vapor-phase reaction of 2,3,5-trimethacarb with photochemically-produced hydroxyl radicals has been estimated as 2.1X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 18 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). A base-catalyzed second-order hydrolysis rate constant of 2.2 L/mole-sec(SRC) was estimated using a structure estimation method(2); this corresponds to half-lives of 4 and 37 days at pH values of 7 and 8, respectively(2). 2,3,5-Trimethacarb absorbs light weakly in the environmental UV spectrum and is stable to light(3).

2,3,5-Trimethacarb's production may result in its release to the environment through various waste streams; it's use as an ingredient in the insecticide trimethacarb(1) will result in its direct release to the environment(SRC). The insecticide trimethacarb is a reaction product consisting of 3,4,5-trimethylphenyl methylcarbamate and 2,3,5-trimethylphenyl methylcarbamate in a ratio between 3.5:1 and 5:1(1).

Occupational exposure to 2,3,5-trimethacarb may occur through inhalation and dermal contact with this compound at workplaces where trimethacarb is produced or used. (SRC)

2,3,5-Trimethacarb's production may result in its release to the environment through various waste streams; it's use as an ingredient in the insecticide trimethacarb will result in its direct release to the environment. If released to air, a vapor pressure of 5.1X10-5 mm Hg at deg 25 C for trimethacarb indicates 2,3,5-trimethacarb will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase 2,3,5-trimethacarb will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 18 hours. Particulate-phase 2,3,5-trimethacarb will be removed from the atmosphere by wet and dry deposition. If released to soil, 2,3,5-trimethacarb is expected to have moderate mobility based upon a...

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)

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.

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...

Other Poison - Carbamate

Inhalation (L793); oral (L793); dermal (L793)

Trimethacarb 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 este...

Two trials for malaria control carried out in Nigeria with Landrin lasted for 2 & 4 days, respectively. there were no complaints among the operators & residents, although in one of the trials a water shortage prevented operators form washing & bathing after work as frequently as planned. Whereas moderate to pronounced inhibition of whole-blood cholinesterase was observed in some sprayers at the end of the day's work, this was considerably less than that observed in the same sprayers when spraying propoxur at other times.

No indication of carcinogenicity to humans (not listed by IARC).

LD50 Rat percutaneous >2000 mg/kg

Toxic to fish. Toxic to bees, in spray formulations.

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious. Positive pressure ventilation techniques with a bag valve mask device may be beneficial. Monitor cardiac rhythm and treat arrhythmias if necessary ... . Start an IV with D5W /SRP: "To keep open", minimal flow rate/. Use lactated Ringer's if signs of hypovolemia are present. For hypotension if signs of hypovolemia are present, administer fluid cautiously. Watch for signs of pulmonary edema ... . Administer atropine. Correct hypoxia before administration ... . In severely poisoned patients, administer pralidoxime chloride (2 PAM). DIRECT PHYSICIAN ORDERS ONLY ... . Treat seizures with adequate atropinization and correction of hypoxia. Rarely is diazepam necessary ... ....