Fenvalerate persistence

Fenvalerate persistence in plants and animals under field conditions... 

Table 20.2 Fenvalerate Persistence in Water, Sediments, and Soils... 

Table 20.3 Fenvalerate Persistence in Plants and Animals under Field Conditions ...

Fenvalerate persists for <10 weeks in the environment and does not accumulate readily in the biosphere. Time for 50% loss (Tb 1/2) in fenvalerate-exposed amphibians, birds, and mammals is 6 to 14 h. For reptiles, terrestrial insects, aquatic snails, and fish, it is usually >14 h to <2 days and for crop plants, it is 2 to 28 days. In nonbiological compartments, Tb 1/2 is up to 6 days in freshwater, 34 days in seawater, 6 weeks in estuarine sediments, and 9 weeks in soils. 

Fenvalerate persists for <10 weeks in the environment and does not accumulate readily in the biosphere. Time for 50% loss (Tbl/2) in fenvalerate-exposed amphibians, birds, and... 

Schimmel SC, Gamas RE, Patrick JM, et al. 1983. Acute toxicity, bioconcentration and persistence of AC 222,705, benthiocarb, chlorpyrifos, fenvalerate, methyl parathion and permethrin in the estuarine environment. J Agric Food Chem 31 104-113. 

Synthetic pyrethroids now account for at least 30% of the world insecticide market and are rapidly replacing other agricultural chemicals for control of insect pests. Fenvalerate is one of the more widely used synthetic pyrethroid insecticides. It is derived from a combination of a-cyano-3-phenoxybenzyl alcohol and a-isopropyl phenylacetate ester. Technical fenvalerate is a mixture of four optical isomers, each occurring in equal amounts but with different efficacies against insect pests. Fenvalerate does not usually persist in the environment for >10 weeks, and it does not accumulate readily in the biosphere. Time for 50% loss (Tb 1/2) in fenvalerate-exposed amphibians, birds, and mammals was 6 to 14 h for reptiles, terrestrial insects, aquatic snails, and fish it was >14 h to <2 days and for various species of crop plants, it was 2 to 28 days. Fenvalerate degradation in water is due primarily to photoactivity, and in soils to microbial activity. Half-time persistence in nonbiological materials is variable, but may range up to 6 days in freshwater, 34 days in seawater, 6 weeks in estuarine sediments, and 9 weeks in soils. 

In biological samples, fenvalerate neither persists for lengthy periods nor is readily accumulated (Smith and Stratton 1986 Cooper 1991). In general, fenvalerate is rapidly (i.e., Tb 1/2 of 6 to 14 h) excreted by amphibians, birds, and mammals has low persistence in various reptiles, terrestrial... 

Fenvalerate is not significantly absorbed or translocated in plants. Cotton, apples, and lettuce treated with fenvalerate contained surface residues of parent fenvalerate 8 weeks after treatment (Reed 1981). In addition to the parent compound, which accounted for 80% of all residues, identified metabolites included 3-phenoxybenzaldehyde, 3-phenoxybenzyl methylbutyric acid, and conjugates of these compounds. Half-time persistence of fenvalerate on plant surfaces is between 2 and 4 weeks, and degradation is primarily a result of weathering (Reed 1981). 

Adsorption and persistence in plants can be modified by other chemicals or by selected carriers, although mechanisms to account for these phenomena are unclear. The application mixture influences adsorption and persistence of fenvalerate. For example, interception and persistence in sugarcane were increased when fenvalerate was applied in a 25% water/75% soybean oil mixture vs. water or soybean oil alone (Smith et al. 1989). Also, biocidal properties of fenvalerate residues on cotton foliage were increased up to 100% due to enhanced persistence of fenvalerate in the presence of toxaphene (Brown et al. 1982). 

The half-time persistence of fenvalerate in the water column is about 10 h... 

Birds that died of fenvalerate poisoning contained residues of 0.1 to 1.26 mg/kg brain fresh weight (FW) and 0.74 mg/kg liver FW, based on acute oral doses of 500 to 4000 mg/kg BW (Table 20.6) juveniles were more sensitive than adults (Bradbury and Coats 1989a). When compared to other synthetic pyrethroids tested in laying hens, fenvalerate provided higher, more persistent residues in tissues (Saleh et al. 1986). Birds given single oral doses as low as 250 mg... 

Cows fed fenvalerate in grain at 10 mg/kg diet for 4 days excreted most of the fenvalerate, essentially unchanged, in urine (Wszolek etal. 1981b). A secondary excretion route is feces, accounting for about 25% of the ingested dose. Milk accounted for 0.44 to 0.64% of the total excreted (Wszolek et al. 1980). Half-time persistence of fenvalerate in milk of treated cows is about 6.4 days (Frank et al. 1984). Effects of low concentrations (1.14 to 6.8 pg/L) of fenvalerate in milk of treated cows on newborn suckling calves are unknown and merit additional research (Frank et al. 

Hill, B.D. 1981. Persistence and distribution of fenvalerate residues in soil under field and laboratory conditions. Jour. Agricul. Food Chem. 29 107-110. 

Marei, A.E.M., L.O. Ruzo, and J.E. Casida. 1982. Analysis and persistence of permethrin, cypermethrin, deltamethrin, and fenvalerate in the fat and brain of treated rats. Jour. Agricul. Food Chem. 30 558-562. 

CASRN 51630-58-1 molecular formula C25H22CINO3 FW 419.92 Soil. Fenvalerate is moderately persistent in soil. The percentage of the initial dosage (1 ppm) remaining after 8 wk of incubation in an organic and mineral soil were 58 and 12%, respectively, while in sterilized controls 100 and 91% remained, respectively (Chapman et al., 1981). 

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