Dimethrin.

286.41

286.41

SRP5SEK6S1

15731

DTXSID8040305

Colourless

26.30000

4.58500

0.986 g/cm3

<25 °C

175 °C(Press: 3.8 Torr)

167.8ºC

1.557

Insoluble in water.

1.3×10-1mol/(m3Pa) at 25℃, HSDB (2015)

Decomposes by strong alkali

Amber Vial, -20°C Freezer, Under inert atmosphere

III

9

UN 3082

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

3082

Employees should be provided with and required to use dust- and splash-proof safety goggles where /pyrethroids/ ... may contact the eyes. /Pyrethroids/|Employees should be provided with and be required to use impervious clothing, gloves, and face shields (eight-inch minimum). /Pyrethroids/|Wear appropriate equipment to prevent: Repeated or prolonged skin contact. /Pyrethrum and pyrethrins/|Wear eye protection to prevent: Reasonable probability of eye contact. /Pyrethrins/|For more Personal Protective Equipment (PPE) (Complete) data for DIMETHRIN (10 total), please visit the HSDB record page.

Skin that becomes contaminated with /pyrethrum/ should be promptly washed or showered with soap or mild detergent and water. /Pyrethrum/|Clothing contaminated with /pyrethrum/ should be placed in closed containers for storage until provision is made for the removal of /pyrethrum/ from the clothing. /Pyrethrum/|Respirators may be used when engineering and work practice controls are not technically feasible, when such controls are in the process of being installed, or when they fail or need to be supplemented. Respirators may also be used for operations which require entry into tanks or closed vessels, and in emergency situations. /Pyrethrum/|Employees who handle /pyrethrum/ ... should wash their hands thoroughly with soap or mild detergent and water before eating, smoking, or using toilet facilities. /Pyrethrum/|For more Preventive Measures (Complete) data for DIMETHRIN (9 total), please visit the HSDB record page.

LD50 Rat (male, female Sherman) oral >15,000 mg/kg

Dimethrin's former(2) production and use as an insecticide(1) may have resulted in its direct release to the environment(SRC).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 31,000(SRC), determined from a structure estimation method(2), indicates that dimethrin is expected to be immobile in soil(SRC). Volatilization of dimethrin from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 7.6X10-5 atm-cu m/mole(SRC), using a fragment constant estimation method(3). However, adsorption to soil is expected to attenuate volatilization(SRC). Dimethrin is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.7X10-5 mm Hg(SRC), determined from a fragment constant method(4). Although biodegradation data for dimethrin are not available, the pyrethroid class of insecticides is readily degraded by environmental microorganisms(5,6) and based upon its structure, dimethrin is also expected to readily biodegrade(5,6).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 31,000(SRC), determined from a structure estimation method(2), indicates that dimethrin is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 7.6X10-5 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 15 hours and 13 days, respectively(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 160 years if adsorption is considered(5). According to a classification scheme(6), an estimated BCF of 520(SRC), from an estimated log Kow of 6.57(7) and a regression-derived equation(8), suggests the potential for bioconcentration in aquatic organisms is high(SRC). However, bioconcentration studies on compounds which are structurally similar suggest that bioconcentration may be lower than that indicated by the regression-derived equations due to the ability of aquatic organisms to readily metabolize this class of compounds(9). Although biodegradation data for dimethrin are not available, the pyrethroid class of insecticides is readily degraded by environmental microorganisms(10,11) and based upon its structure, dimethrin is also expected to readily biodegrade(10,11).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), dimethrin, which has an estimated vapor pressure of 1.7X10-5 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(SRC). Vapor-phase dimethrin 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 4 hours(SRC), calculated from its rate constant of 1.1X10-10 cu cm/molecule-sec at 25 °C(SRC) determined using a structure estimation method(3). Particulate-phase dimethrin may be removed from the air by wet and dry deposition(SRC).

The rate constant for the vapor-phase reaction of dimethrin with photochemically-produced hydroxyl radicals has been estimated as 1.1X10-10 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 4 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The rate constant for the vapor-phase reaction of dimethrin with photochemically- produced ozone has been estimated as 4.3X10-16 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 38 minutes at an atmospheric concentration of 7X10+11 hydroxyl radicals per cu cm(2). Reaction with nitrate radicals with vapor-phase dimethrin may also be an important degradation mechanism in air(SRC). A base-catalyzed second-order hydrolysis rate constant of 4.0X10-2 l/mole-sec(SRC) was estimated using a structure estimation method(3); this corresponds to half-lives of 5.5 years and 200 days at pH values of 7 and 8, respectively(3).

An estimated BCF of 520 was calculated for dimethrin(SRC), using an estimated log Kow of 6.57(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is high(SRC). However, bioconcentration studies on compounds which are structurally similar suggest that bioconcentration may be lower than that indicated by the regression-derived equations due to the ability of aquatic organisms to readily metabolize this class of compounds(4).

Using a structure estimation method based on molecular connectivity indices(1), the Koc for dimethrin can be estimated to be 31,000 (SRC). According to a classification scheme(2), this estimated Koc value suggests that dimethrin is expected to be immobile in soil(SRC).

The Henry's Law constant for dimethrin is estimated as 7.6X10-5 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that dimethrin is expected to volatilize from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 15 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 13 days(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column(SRC). The estimated volatilization half-life from a model pond is 160 years if adsorption is considered(3). Dimethrin's Henry's Law constant(1) indicates that volatilization from moist soil surfaces may occur(SRC). Dimethrin is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.7X10-5 mm Hg(SRC), determined from a fragment constant method(3).

Occupational exposure to dimethrin may have occured through inhalation and dermal contact with this compound at workplaces where dimethrin was produced or used. (SRC)

... Four rabbits were given 5 ml/kg of undiluted dimethrin by intubation. Urine was collected every 24 hr over a 72 hr period. Identification of two possible metabolites in the urine indicated that dimethrin was absorbed.

... Dimethrin (5 mg/kg), administered by intubation to rabbits, is metabolized (by reduction) and excreted in the urine as chrysanthemumic acid and the glucuronic ester of 2,4-dimethyl benzoic acid.|The low toxicity of pyrethroids in mammals is due largely to their rapid biotransformation by ester hydrolysis and/or hydroxylation. /Pyrethroids/

The additives (e.g. petroleum distillate), when present, represent a greater toxic threat to the patient than the active ingredient itself. ... Emesis should not be induced when petroleum distillate additives are present. ... The alert person with an intact gag reflex & a sublethal pyrethrum ingestion without other toxic constituents may have emesis induced by ipecac, followed by a saline cathartic & slurry of activated charcoal. ... Pulmonary & allergic sequelae are treated symptomatically with airway maintenance, oxygen, & ventilatory assistance as required. Standard drugs and management protocols may be used for treatment of bronchospasm & anaphylaxis. Seizures are treated with diazepam. /Pyrethrum and synthetic pyrethroids/|Basic treatment: . Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Anticipate seizures and treat if necessary... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool. Administer activated charcoal ... . /Pyrethrins, pyrethroids, and related compounds/|Advanced treatment: Consider orotracheal or nasotracheal intubation for air way control in the patient who is unconscious. 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. Watch for signs of fluid overload ... . Treat seizures with diazepam (Valium) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Pyrethrins, pyrethroids, and related compounds/|Skin decontamination. Wash skin promptly with soap and water ... . If irritant or paresthetic effects occur, obtain treatment by a physician. Because volatilization of pyrethroids apparently accounts for paresthesia affecting the face, strenuous measures should be taken (ventilation, protective face mask and hood) to avoid vapor contact with the face and eyes. Vitamin E oil preparations (dL-alpha tocopheryl acetate) are uniquely effective in preventing and stopping the paresthetic reaction. They are safe for application to the skin under field conditions. Corn oil is somewhat effective, but possible side effects with continuing use make it less suitable. Vaseline is less effective than corn oil. Zinc oxide actually worsens the reaction. /Pyrethroids/|For more Antidote and Emergency Treatment (Complete) data for DIMETHRIN (6 total), please visit the HSDB record page.

The clinical manifestations of inhalation exposure to pyrethrins can be local or systemic. Localized reactions confined to the upper respiratory tract include rhinitis, sneezing, scratchy throat, oral mucosal edema, and even laryngeal mucosal edema. Localized reaction of the lower respiratory tract include cough, shortness of breath, wheezing, and chest pain. An asthma like reaction occurs with acute exposures in sensitized patients. Hypersensitivity pneumonitis characterized by chest pain, cough, dyspnea, & bronchospasm may occur in an individual chronically exposed. /Pyrethrum and synthetic pyrethroids/|The allergenic properties of pyrethroids /with early pyrethrum preparations/ are marked in comparison with other pesticides. Many cases of contact dermatitis and respiratory allergy have been reported. Persons sensitive to ragweed pollen are particularly prone to such reactions. Preparations containing synthetic pyrethroids are less likely to cause allergic reactions than are the preparations made from pyrethrum powder. /Pyrethroids/

2,4-dimethylbenzyl chrysanthemumate

USEPA/OPP Pesticide Code 034101; Trade Names: ENT 21,170.

Discontinued by McLaughlin Gormley King|Synthetic compound produced to duplicate or improve more or less successfully on the biological activity of the pyrethrum plant.

INSECTICIDES