Relation between Intensity of Biocide Practice and Residues of Anticoagulant Rodenticides in Red Foxes (Vulpes vulpes)

PLoS One. 2015 Sep 29;10(9):e0139191. doi: 10.1371/journal.pone.0139191. eCollection 2015.


Anticoagulant rodenticides (ARs) are commonly used to control rodent infestations for biocidal and plant protection purposes. This can lead to AR exposure of non-target small mammals and their predators, which is known from several regions of the world. However, drivers of exposure variation are usually not known. To identify environmental drivers of AR exposure in non-targets we analyzed 331 liver samples of red foxes (Vulpes vulpes) for residues of eight ARs and used local parameters (percentage of urban area and livestock density) to test for associations to residue occurrence. 59.8% of samples collected across Germany contained at least one rodenticide, in 20.2% of cases at levels at which biological effects are suspected. Second generation anticoagulants (mainly brodifacoum and bromadiolone) occurred more often than first generation anticoagulants. Local livestock density and the percentage of urban area were good indicators for AR residue occurrence. There was a positive association between pooled ARs and brodifacoum occurrence with livestock density as well as of pooled ARs, brodifacoum and difenacoum occurrence with the percentage of urban area on administrative district level. Pig holding drove associations of livestock density to AR residue occurrence in foxes. Therefore, risk mitigation strategies should focus on areas of high pig density and on highly urbanized areas to minimize non-target risk.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 4-Hydroxycoumarins / poisoning
  • Animals
  • Anticoagulants / poisoning*
  • Arvicolinae
  • Environmental Exposure*
  • Environmental Monitoring
  • Foxes*
  • Germany
  • Liver / pathology*
  • Rodenticides / poisoning*


  • 4-Hydroxycoumarins
  • Anticoagulants
  • Rodenticides
  • bromfenacoum
  • bromadiolone
  • difenacoum

Grant support

This study was funded by the Federal Environment Agency ( within the Environment Research Plan of the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (grant number 3710 63 401). The funders had no role in study design, data collection and analysis, or decision to publish. An employee of the Federal Environment Agency provided comments and authorised the manuscript.