title: Field evaluation of an avian risk assessment model.
abstract: We conducted two laboratory subacute dietary toxicity tests and one outdoor subacute dietary toxicity test to determine the effectiveness of the U.S. Environmental Protection Agency's deterministic risk assessment model for evaluating the potential of adverse effects to birds in the field. We tested technical-grade diazinon and its D.Z.N 50W (50% diazinon active ingredient wettable powder) formulation on Canada goose (Branta canadensis) goslings. Brain acetylcholinesterase activity was measured, and the feathers and skin, feet, and gastrointestinal contents were analyzed for diazinon residues. The dose-response curves showed that diazinon was significantly more toxic to goslings in the outdoor test than in the laboratory tests. The deterministic risk assessment method identified the potential for risk to birds in general, but the factors associated with extrapolating from the laboratory to the field, and from the laboratory test species to other species, resulted in the underestimation of risk to the goslings. The present study indicates that laboratory-based risk quotients should be interpreted with caution.
authors.affiliation: U.S. Geological Survey, Patuxent Wildlife Research Center, Beltsville Lab, c/o BARC-East Building 308, 10300 Baltimore Avenue, Beltsville, Maryland 20705, USA. nimish_vyas@usgs.gov
authors.forename: Nimish B
authors.initials: NB
authors.lastname: Vyas
authors.forename: James W
authors.initials: JW
authors.lastname: Spann
authors.forename: Craig S
authors.initials: CS
authors.lastname: Hulse
authors.forename: Shannon L
authors.initials: SL
authors.lastname: Borges
authors.forename: Richard S
authors.initials: RS
authors.lastname: Bennett
authors.forename: Martin
authors.initials: M
authors.lastname: Torrez
authors.forename: Bruce I
authors.initials: BI
authors.lastname: Williams
authors.forename: Robert
authors.initials: R
authors.lastname: Leffel
mesh_terms: D000115:Acetylesterase / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D001717:Birds / Q000378:metabolism; D001921:Brain / Q000187:drug effects / Q000201:enzymology; D003976:Diazinon / Q000737:chemistry / Q000494:pharmacology; D008954:Models, Biological; D011157:Population Dynamics; D018570:Risk Assessment / Q000592:standards; D018675:Toxicity Tests / Q000592:standards*; D014481:United States; D014484:United States Environmental Protection Agency
chemical_list: D000115:Acetylesterase; D003976:Diazinon