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Accession Number 5004930

Title Effects of chlorfenapyr on adult birds

Project Description Chlorfenapyr is a halogenated pyrrole insecticide that is registered for use in 31 countries.

Emergency exemptions have been granted by EPA for the use of chlorfenapyr on cotton in at

least 11 states since 1995. Chlorfenapry is persistent in soil (avg. half life of 1 yr), sediment (avg.

half life of 1.1 yr), and water (avg. half life of 0.8 yr); has high acute, subacute, and chronic

(reporductive) toxicity in birds; and poses an acute poisoning hazard to aquatic organisms.

Results of experiments with laboratory mice and rats revealed a number of histological

abnormalities, including nerve tissue degeneration. In March 2000, the EPA issued a critical

evaluation of chlorfenapyr that caused the manufacturer to withdraw its application for use on

cotton; other applications remain and the manufacturer can resubmit the cotton application. The

EPA action was based heavily on the results of studies of effects on birds (mallards, bobwhite,

red-winged blackbirds). Unfortunately, no information has been collected on biochemical or

histological (micropathology) endpoints, nor were any tissues analyzed for chlorfenapyr

metabolites. Thus, there are no biological markers available for determining exposure of birds to

chlorfenapyr. The objectives of this study are to describe the pathological effects of chronic

exposure, identify biochemical responses, and determine tissue retention potentials in mallard

ducks. In a preliminary feeding trial, 55 mallards will be fed diets containing either of five

concentrations of technical or formulation chlorfenapyr for 10 weeks. Birds that die during the

study, and all birds euthanized at the end of the feeding trial, will be necropsied and tissues will

be removed for histological examination, biochemical assessment, and chemical analysis for

chlorfenapyr. Results of the preliminary feeding trial will be used to determine appropriate dietary

concentrations, tissues, and biochemical procedures for the primary study to be conducted the

following year. Results of the primary study will be used to characterize tissue and biochemical

effects of chlorfenapyr and to establish biomarkers or a set of biological responses (criteria ) that

are diagnostic for exposure to chlorfenapyr.

Keywords acute, agriculture, biochemistry, biomarker, chronic, histology, insecticide, mallard, pathology,

physiology, sublethal, toxicity,

Principal Peter H Albers, USGS Patuxent Wildlife Research Center:; Mark J

Investigators Melancon, USGS Patuxent Wildlife Research Center:; George

Noguchi, U.S. Fish and Wildlife Service, Division of Environmental Quality:; David E Green, USGS Patuxent Wildlife Research Center:; Patrice N Klein, The Humane Society of the United States:;

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