化合物详情

Pesticide Ecotoxicity Data from EPA: 30

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), dimethipin, which has a measured vapor pressure of 3.8X10-7 mm Hg at 25 °C(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase dimethipin is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and ozone(SRC); the half-lives for these reactions in air are estimated to be about 3.0 and 3.7 hours, respectively(3,SRC). Particulate-phase dimethipin may be physically removed from the air by wet and dry deposition(SRC).

A Koc of 3.3 was determined in clay (%organic matter 4.8, pH 5.9)(1,3). According to a recommended classification scheme(2), the measured Koc of dimethipin suggests it is expected to have very high mobility in soil(SRC).

An estimated BCF of 0.44 was calculated for dimethipin(SRC), using a measured log Kow of -0.17(1) and a recommended regression-derived equation(2). According to a classification scheme(3), this BCF suggests that bioconcentration in aquatic organisms is low(SRC).

The Henry's Law constant for dimethipin is 1.7X10-8 atm-cu m/mole(1). This value indicates that dimethipin will be essentially nonvolatile from water surfaces(2,SRC). Volatilization from wet and dry soil surfaces is not expected based on dimethipin's measured Henry's Law constant(1) and vapor pressure of 3.8X10-7 mm Hg, respectively(2).

The rate constant for the vapor-phase reaction of dimethipin with photochemically-produced hydroxyl radicals has been estimated as 1.3X10-10 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1,SRC). This corresponds to an atmospheric half-life of about 3.0 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1,SRC). The rate constant for the vapor phase reaction with ozone has been estimated as 7.4X10-17 cu cm/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 3.7 hours at an average ambient ozone concentration of 7X10+11 molecules/cu cm(1,SRC). Stability of dimethipin to light is greater than or equal to 7 days at 25 °C(2). In aqueous solution, dimethipin is degraded(2); rate and method of degradation were not speci...

Dimethipin's production and use as a defoliant and seed desiccant(1,2) will result in its release to the environment(SRC).

Occupational exposure to dimethipin may occur through inhalation of dust particles and dermal contact with this defoliant/desiccant during or after its application or at workplaces where dimethipin is produced or used. (SRC)

Dimethipin will be released to the environment from its production and use as a defoliant and seed desiccant. If released to air, a measured vapor pressure of 3.8X10-7 mm Hg at 25 °C indicates that dimethipin will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase dimethipin will be degraded in the atmosphere by reaction with ozone and photochemically-produced hydroxyl radicals; the half-lives for these reactions have been estimated as 3.7 and 3.0 hours, respectively. Particulate-phase dimethipin may be physically removed from the atmosphere by wet and dry deposition. If released to soil, a measured Koc of 3.3 indicates that dimethipin will have very high mobility. Volatilization from wet and dry soil surfaces is not expected based on this compound's H...

Hepatic

LC50 (rat) > 1,200 mg/m3

Occupational hepatotoxin - Secondary hepatotoxins: the potential for toxic effect in the occupational setting is based on cases of poisoning by human ingestion or animal experimentation.

Oral Chronic Reference Dose Reference: OPP

LD50 Rat oral 1,660 mg/kg /Harvade/

Extreme eye irritant, not a dermal irritant (rabbits). Weak sensitizer (guinea pigs).

Fraction of Contaminant Absorbed Dermally from Soil: 0.1

CLASSIFICATION: C; possible human carcinogen. BASIS FOR CLASSIFICATION: Classification is based on an elevated combined incidence of pulmonary adenomas/carcinomas in male, but not in female, CD-1 mice. A rat study is undergoing further evaluation. HUMAN CARCINOGENICITY DATA: None. ANIMAL CARCINOGENICITY DATA: Limited.

Fraction of Contaminant Absorbed Dermally from Soil: 0.1