Environmental Monitoring and Assessment

, Volume 186, Issue 2, pp 895–906

Exposure pathways of anticoagulant rodenticides to nontarget wildlife

  • John E. Elliott
  • Sofi Hindmarch
  • Courtney A. Albert
  • Jason Emery
  • Pierre Mineau
  • France Maisonneuve
Article

DOI: 10.1007/s10661-013-3422-x

Cite this article as:
Elliott, J.E., Hindmarch, S., Albert, C.A. et al. Environ Monit Assess (2014) 186: 895. doi:10.1007/s10661-013-3422-x

Abstract

Second-generation anticoagulant rodenticides are widely reported to contaminate and poison nontarget wildlife, primarily predatory birds and mammals. Exposure pathways, however, have not been well defined. Here, we examined potential movement of rodenticides from deployment of bait to exposure of small mammals and other biota. At two adjacent working farms, we placed baits containing either brodifacoum or bromadiolone. We monitored movement of those compounds to the surrounding environment by collecting small mammals, birds, and invertebrates. Similar collections were made at a third agricultural setting without active bait deployment, but located among intensive livestock production and regular rodenticide use by farmers. Livers and whole invertebrate samples were analyzed for rodenticides using a sensitive LC-MSMS method. Norway rats (Rattus norvegicus) from both baited and non-baited farms had residues of brodifacoum or bromadiolone, implicating rats as an important exposure pathway to wildlife. Among 35 analyzed nontarget small mammals, a single vole had high hepatic residues (18.6 μ/g), providing some indication of a small mammal pathway. One song sparrow (Melospiza melodia) sample from a baited farm contained 0.073 μg/g of brodifacoum in liver, while 0.39 μg/g of diphacinone was measured in a pool of carrion beetles (Dermestes spp.) from the non-baited farm area, implicating avian and invertebrate components in exposure pathways. Regurgitated pellets of barn owl (Tyto alba) selected randomly from baited farms contained no detectable rodenticide residues, while 90 % of owl pellets collected from a variety of farms, and selected for the presence of rat fur, contained detectable anticoagulant residues. We recorded behavior of a captive sample of a representative songbird, the house sparrow (Passer domesticus); they readily entered bait stations and fed on (unloaded) bait.

Keywords

Anticoagulants Exposure pathways Nontargets Raptor Rat 

Copyright information

© Her Majesty the Queen in Right of Canada as represented by: Environment of Canada 2013

Authors and Affiliations

  • John E. Elliott
    • 1
  • Sofi Hindmarch
    • 2
  • Courtney A. Albert
    • 3
  • Jason Emery
    • 4
  • Pierre Mineau
    • 5
  • France Maisonneuve
    • 5
  1. 1.Science and Technology Branch, Environment CanadaPacific and Yukon RegionDeltaCanada
  2. 2.RichmondCanada
  3. 3.Canadian Wildlife Service, Environment CanadaPacific and Yukon RegionDeltaCanada
  4. 4.SOLITUDO Environmental Services Inc.DeltaCanada
  5. 5.Science and Technology Branch, Environment CanadaNational Wildlife Research CenterOttawaCanada

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