Partitioning of etofenprox under simulated California rice-growing conditions

BACKGROUND: The pyrethroid insecticide etofenprox is of current interest to rice farmers in the Sacramento Valley owing to its effectiveness against the rice water weevil, Lissorhoptrus oryzophilus Kuschel. This study aimed to describe the partitioning of etofenprox under simulated rice field condit...

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Vydané v:	Pest management science Ročník 66; číslo 1; s. 28 - 34
Hlavní autori:	Vasquez, Martice E, Gunasekara, Amrith S, Cahill, Thomas M, Tjeerdema, Ronald S
Médium:	Journal Article
Jazyk:	English
Vydavateľské údaje:	Chichester, UK John Wiley & Sons, Ltd 2010 Wiley Wiley Subscription Services, Inc
Predmet:	Adsorption analysis Biological and medical sciences California chemistry Comparative analysis Control Desorption Detection limits etofenprox fugacity model Fundamental and applied biological sciences. Psychology growth & development Henry's law constant Insecticides Insecticides - chemistry Insects Lissorhoptrus oryzophilus Models, Chemical Moisture content Nitriles Nitriles - chemistry Organic carbon Oryza Oryza - growth & development Oryza sativa partitioning Pest control Phytopathology. Animal pests. Plant and forest protection Protozoa. Invertebrates pyrethrins Pyrethrins - chemistry pyrethroid Pyrethroids Rice simulation models Soil Soil - analysis Soil water soil-water distribution coefficient Sorption sorption coefficient Studies Suspended sediments Temperature Vapor pressure Volatilization Water Water - analysis California United States North America America USA, California, Sacramento Valley Monocotyledones Insecticide Pesticides Pyrethroids Modeling sorption coefficient Sorption Etofenprox Oryza Partitioning Simulation Gramineae Angiospermae Herbaceous plant Spermatophyta Henry's law constant fugacity model pyrethroid
ISSN:	1526-498X, 1526-4998, 1526-4998
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Shrnutí:	BACKGROUND: The pyrethroid insecticide etofenprox is of current interest to rice farmers in the Sacramento Valley owing to its effectiveness against the rice water weevil, Lissorhoptrus oryzophilus Kuschel. This study aimed to describe the partitioning of etofenprox under simulated rice field conditions by determining its Henry's law constant (H) (an estimate of volatilization) and organic carbon-normalized soil-water distribution coefficient (Koc) at representative field temperatures. A comparison of etofenprox and λ-cyhalothrin is presented using a level-1 fugacity model.RESULTS: Experimental determination of H revealed that etofenprox partitioned onto the apparatus walls and did not significantly volatilize; the maximum value of H was estimated to be 6.81 x 10⁻¹ Pa m³ mol⁻¹ at 25 °C, based on its air and water method detection limits. Calculated values for H ranged from 5.6 x 10⁻³ Pa m³ mol⁻¹ at 5 °C to 2.9 x 10⁻¹ Pa m³ mol⁻¹ at 40 °C, based on estimated solubility and vapor pressure values at various temperatures. Log Koc values (at 25 °C) were experimentally determined to be 6.0 and 6.4 for Princeton and Richvale rice field soils, respectively, and were very similar to the values for other pyrethroids. Finally, temperature appears to have little influence on etofenprox sorption, as the log Koc for the Princeton soil at 35 °C was 6.1.CONCLUSION: High sorption coefficients and relatively insignificant desorption and volatilization of etofenprox suggest that its insolubility drives it to partition from water by sorbing to soils with high affinity. Offsite movement is unlikely unless transported in a bound state on suspended sediments.
Bibliografia:	http://dx.doi.org/10.1002/ps.1826 ark:/67375/WNG-N6JCSK27-V ArticleID:PS1826 istex:BFDE93B4A97ABBDE379A963C92BA97F3BAA6BFA7 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 14 ObjectType-Article-1 ObjectType-Feature-2 content type line 23 ObjectType-Article-2
ISSN:	1526-498X 1526-4998 1526-4998
DOI:	10.1002/ps.1826