Toxicokinetics of imidacloprid-coated wheat seeds in Japanese quail (Coturnix japonica) and an evaluation of hazard

Environmental Science & Technology
By: , and 

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Abstract

Birds are potentially exposed to neonicotinoid insecticides by ingestion of coated seeds during crop planting. Adult male Japanese quail were orally dosed with wheat seeds coated with an imidacloprid (IMI) formulation at either 0.9 mg/kg body weight (BW) or 2.7 mg/kg BW (~3 and 9% of IMI LD50 for Japanese quail, respectively) for 1 or 10 days. Quail were euthanized between 1 and 24 h post-exposure to assess toxicokinetics. Analysis revealed rapid absorption (1 h) into blood, and distribution to brain, muscle, kidney and liver. Clearance to below detection limits occurred at both dose levels and exposure durations in all tissues within 24 h. Metabolism was extensive, with 5-OH-IMI and IMI-olefin detected at greater concentrations than IMI in tissues and fecal samples. There was no lethality or overt signs of toxicity at either dose level. Furthermore, no evidence of enhanced expression of mRNA genes associated with hepatic xenobiotic metabolism, oxidative DNA damage or alterations in concentrations of corticosterone and thyroid hormones was observed. Application of the toxicokinetic data was used to predict IMI residue levels in liver with reasonable results for some field exposure and avian mortality events. It would appear that some affected species are either consuming larger quantities of seeds or exhibit differences in ADME or sensitivity than predicted by read-across from these data.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Toxicokinetics of imidacloprid-coated wheat seeds in Japanese quail (Coturnix japonica) and an evaluation of hazard
Series title Environmental Science & Technology
DOI 10.1021/acs.est.8b07062
Volume 53
Issue 7
Year Published 2019
Language English
Publisher American Chemical Society
Contributing office(s) Patuxent Wildlife Research Center, California Water Science Center, Oregon Water Science Center
Description 10 p.
First page 3888
Last page 3897