Photodecomposition of resmethrin and related pyrethroids

Ueda, Kenzo; Gaughan, Loretta C.; Casida, John E.

doi:10.1021/jf60192a014

Cited by 69 publications

(62 citation statements)

References 5 publications

(6 reference statements)

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“…To assess subacute and chronic toxicity of the pyrethroids, groups of 12 to 20 each of males and females (in the case of chronic allethrin feeding each 30 males and females per group) were fed a diet containing the specified concentration of the compound. Table 8 summarizes the experimental designs and compound-related changes in several of these feeding testings.…”

Section: Subacute and Chronic Toxicitymentioning

confidence: 99%

Degradation, metabolism and toxicity of synthetic pyrethroids.

Miyamoto¹

1976

Environ Health Perspect

202

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Synthetic pyrethroidal compounds undergo biodegradation in mammals both oxidatively and hydrolytically, and depending on the type of compound, either of the pathways may predominate. Thus, (+) -or (±) -trans isomers of the chrysanthemumate ester of primary alcohols such as fenothrin, furamethrin, proparthrin, resmethrin, and tetramethrin (and possibly permethrin, too) are metabolized mainly through hydrolysis of the ester linkage, with subsequent oxidation and/or conjugation of the component alcohol and acid moieties. On the other hand, the corresponding (+ )-cis enantiometers and chrysanthemumate of secondary alcohols like allethrin are resistant to hydrolytic attack, and biodegraded via oxidation at various sites of the molecule. These rapid metabolic degradations, together with the presumable incomplete absorption from the gastrointestinal tract, would generally contribute to the low acute toxicity of synthetic pyrethroids.These compounds are neither skin irritants nor skin sensitizers, and inhalation toxicity as well as dermal toxicity are fairly low. Neither is teratogenic in rats, mice, and/or rabbits or mutagenic on various bacterial strains. Subacute and chronic feeding of higher amounts of the compounds to rats invariably causes some histopathological changes in liver; however, these are neither indicative nor suggestive of tumorigenicity.Based on existing toxicological information, the present recommended use patterns might afford sufficient safety margin on human population.However, in extending usage to agricultural pest control, much more extensive investigations should be forthcoming from both chemical and biological aspects, since there is scant information on the fate of these pyrethroids in the environment. Also several of the compounds may be very toxic to certain kinds of fish and arthropods.

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Section: Subacute and Chronic Toxicitymentioning

confidence: 99%

Degradation, metabolism and toxicity of synthetic pyrethroids.

Miyamoto¹

1976

Environ Health Perspect

202

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“…A similar photodegradation profile, no isomerization with oxidation and ester cleavage, was reported for aqueous photolysis of trans-resmethrin. 34) The oxidative cleavage of the C=C bond at the 2-methylprop-l-enyl group predominantly proceeded to form the aldehyde derivative (6) subsequently oxidized to carboxylic acid (5). Since the ozonolysis of olefins forms the corresponding aldehydes, 35) the atmospheric ozone is the most likely reactant for trans-1.…”

Section: Discussionmentioning

confidence: 99%

Behavior of cyphenothrin in aquatic environment

et al. 2017

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The behavior of cyphenothrin (1) [(RS)-α-cyano-3-phenoxybenzyl (1RS)-cis-trans-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylate] in an aquatic environment was investigated by using the 14 C-labeled trans and cis isomers. In parallel with the rapid partition from water phase to bottom sediment, 1 was degraded with the first-order half-lives of 2.0 (trans-1) and 7.3 days (cis-1) in the water-sediment system under dark conditions. 1 underwent extensive microbial degradation via ester cleavage to form 3-phenoxybenzoic acid, finally forming bound residues and mineralizing to CO 2 . Aqueous photolysis significantly accelerated the degradation of 1 with a half-life of <1 day, mainly via photo-induced oxidation at the 2-methylprop-1-enyl group and ester cleavage without cis-trans isomerization. These results strongly suggest that 1 is unlikely to persist in the actual aquatic environment due to its rapid photolysis and extensive microbial degradation.

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“…A possible means of regulating decomposition rates can be addition of a special sensitizer into a pesticide formulation to absorb the near-land sunlight followed by transfer of this energy to the pesticide molecules, which then should decompose. Several regulating chemicals have been experimented in 70-80 s, but, for some reasons, these sensitizers have found no practical use in plant protection [14,15,17,18,24]. The authors have earlier studied the photochemical interaction between several pesticide chemicals and sensitizers in the form of fine particles and thin films in the outdoor and laboratory conditions [25][26][27].…”

Section: Photodecomposition Of Pesticide Pollutants Relevant To Ambiementioning

confidence: 99%

“…These flow-tube experiments simulate the (photo-) chemical reactions with residues of both the pesticide and the non-pesticide compounds deposited from the air onto plant foliage. Photochemical decomposition of several pesticide compounds was studied in the form of either the liquid solutions in glass test-tubes or the (semi-) solid films formed on glass plates [14][15][16][17][18][19]. The reaction rates and the quantum yields were measured under action of both the solar radiation and the laboratory sources of actinic light.…”

Section: Introductionmentioning

confidence: 99%

Photochemical Decomposition of Pesticide Chemicals in Aerosol Particles and Thin Films Relevant to Environmental Conditions

Samsonov¹

2014

JCCE

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Contamination of the environment by pesticides is the inevitable aftermath of plant protection, and a substantial portion of pesticide pollutants exists in the form of aerosol particles levitated in the air and deposited on plants, and as the pesticide residues (thin films) on the surface of plant leaves. The sunlight photolysis could be the resource for the accelerated photochemical decomposition of pesticide compounds to minimize the long-term environmental contamination. The rates of photochemical decomposition of pesticide chemicals propiconazole (commercial formulation Tilt) and haloxyfop-ethoxyethyl (Zellek) were measured in particles of 0.12-1.3 μm in diameter and in films 0.04-0.2 μm thick. A specific polyaromatic sensitizer Shirvanol was used to induce accelerated decomposition of the above pesticide particulates under both the solar radiation and the artificial UV light. It was established that propiconazole decomposes by the sensitized photo-oxidation only, but haloxyfop-ethoxyethyl reacts in both the oxygen (air) and oxygen-free mediums via both the direct and sensitized reactions. The photochemical mechanisms are hypothesized and argued for the oxidative and non-oxidative decompositions. The haloxyfop-ethoxyethyl (Zellek) residues formed on foliage upon pesticide treatments of agricultural fields would essentially decompose under sunlight via a direct photoreaction in 4-6 weeks, but the propiconazole (Tilt) contaminants probably need more time.

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Photodecomposition of resmethrin and related pyrethroids

Cited by 69 publications

References 5 publications

Degradation, metabolism and toxicity of synthetic pyrethroids.

Degradation, metabolism and toxicity of synthetic pyrethroids.

Behavior of cyphenothrin in aquatic environment

Photochemical Decomposition of Pesticide Chemicals in Aerosol Particles and Thin Films Relevant to Environmental Conditions

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