Diazinon Dissipation From Vegetation, Occurrence in Earthworms, and Presence in Avian Gastrointestinal Tracts Collected From Apple Orchards Following D-Z-N® 50w Application

Abstract

Abstract-Comprehensive residue determinations were made in biota inhabiting orchards receiving diazinon application as part of ecotoxicology studies in the United States. The states of Washington and Pennsylvania served as study areas representing different climatic and agricultural practices. Mean diazinon application was 3.0 to 3.1 kg a.i./ha in the orchards, and a subsequent exponential reduction in concentrations occurred on vegetation. Diazinon was present in earthworms following application, and 23 of 25 avian species evaluated in treatment orchards contained diazinon in their gastrointestinal (GI) tracts. Diazinon residues were present in 18 of the 20 avian species that were represented by more than one sample. Quantifiable residues were present in 17 of the bird species. Earthworms from Pennsylvania orchards contained more frequent and higher diazinon concentrations than did earthworms from Washington orchards ( p Ͻ 0.005). Passerine exposure to diazinon was not different when comparing diazinon concentrations in individual species between the two geographic regions (0.23 Ͻ p Ͻ 0.06). Exposures were different for American robins and European starlings ( p ϭ 0.03) in Washington and for Northern cardinals and European starlings ( p ϭ 0.03) in Pennsylvania. Residues in GI tracts suggest that lethal exposures were limited to the day of application and the 4 d following application. Data indicate that, under conditions of repeated diazinon application, ingestion of earthworms poses risks to passerines.

The Influence of Study Species Selection on Estimates of Pesticide Exposure in Free-Ranging Birds

“…It is also possible that chipping sparrows are less sensitive to the anti-ChE exposures, and therefore their lower abundance may not be a reflection of adverse effects but an artifact of other aspects of their ecology (e.g., habitat preferences). Robins have frequently been the focus of orchard pesticide studies, and significant effects have been Environmental Management (2014) 53:416-428 425 observed in this species (Cobb et al 2000;Fluetsch and Sparling 1994;Gill et al 2000;Graham and DesGranges 1993). However, Graham and DesGranges (1993) and Rondeau and DesGranges (1995) both reported significant plasma ChE depression in both chipping sparrows and robins in areas treated with OPs, but chipping sparrows were the only species to demonstrate significant brain ChE depression in Christmas tree plantations.…”