New inshights in the Anticoagulant Rodenticides Risk Assessment on Non-Target Species

  • PI: Antonio J. García-Fernández
  • Co-PI: Pilar Gómez-Ramírez

This project is in line with the two main research lines developed by the principal investigators started in 1992 and 1995 respectively:

  • For the first line (1992), wildlife species are used as sentinels of risks caused by environmental pollution to assess scenarios of exposure and effects in individuals and populations.
  • In the second line, effects of contaminants and their mixtures are evaluated experimentally, focusing on in vitro assays, to be consistent with 3Rs principles in animal testing studies (replacement, reduction and refinement). These techniques include: to avoid the use of laboratory animals, little or non-invasive field sampling, to avoid killing animals and use carcasses from animals admitted death or euthanised due to health problems,  to validate analytical techniques that use small sample amounts, to design in vitro assays, etc.


The solution for an environmental problem caused by chemical substances requires a suitable risk assessment (ERA) or, at least, the collection of enough data to estimate the potential risks to propose more suitable and feasible actions. The widespread use of antIcoaguiant rodenticides (ARs) to control rodent plagues in urban, semi-urban, farming and sometimes forest environments may pose a risk for the species ingesting the commercial baits (primary intoxication) or for those non-target species predating on target species (secondary intoxication). In addition, some ARs are able to cause resistance or high toxicity. The problems derived are posing a worldwide concern. This explains the increasing restrictions and limitations for extending the authorization of these products in Europe. Meanwhile, managers and administrators in charge of decision-making processes need more information and tools to improve the ERA for human, animal and environmental health. The current greatest concern is probably focused on free-living non-target predatory and scavenger species.

There is a need to improve the knowledge about the risks of ARs for these species with a better understanding of: i) exposure routes; ii) the cause of the differences in sensitivity among species; iii) the relation between residues of mixtures of ARs and their potential toxicity at individual level; iv) the estimated quantification of mortalities to justify the new regulations to minimise the risks and adverse effects; v) the potential sublethal effects and their long-term consequences for populations; vi) the high probability emergence of adverse effects due to repeated exposure to low doses of ARs.


In light of this situation, the main objective of this project is to improve ecological and toxicological risk assessments of secondary exposure to ARs and their mixtures in free-living non-target predatory and scavenger species, by an improvement of the knowledge of sublethal effects, interspecific differences and toxic reference values.

From this main aim, three specific objectives are proposed:

1) To study inter- and intra-species differences in the exposure to ARs;

2) To propose, in each species, liver toxic reference values for the diagnosis of the cause of death or intoxication;

3) To assess in vitro, in each species, sublethal effects related to exposure to single and mixtures of ARs commonly found in free-living animals of the species under study.