Predictive framework for estimating the risks to raptors from ecologically relevant exposure to second generation anticoagulant rodenticides

TY - JOUR

T1 - Predictive framework for estimating the risks to raptors from ecologically relevant exposure to second generation anticoagulant rodenticides

AU - Sanchez-Paredes, Ciara M

AU - Burgess, Malcolm D

AU - Fryer, Michael

AU - Pereira, M Glória

AU - Arnold, Kathryn E

N1 - Copyright © 2025. Published by Elsevier B.V. This is an author-produced version of the published paper. Uploaded in accordance with the University’s Research Publications and Open Access policy.

PY - 2025/8/25

Y1 - 2025/8/25

N2 - Globally, populations of many raptor species are declining for reasons including exposure to chemical contaminants. Second Generation Anticoagulant Rodenticide (SGAR) residues are commonly found in the livers of raptors, indicating dietary exposure and potentially secondary poisoning. There is a gap in our understanding of SGAR exposure for raptors at different life stages and under different usage regimes. We develop a new modelling framework for non-target species to refine the commonly applied risk assessment using the common kestrel (Falco tinnunculus) as a case study. Our scenarios simulate high and low rodent consumption by raptors with high and low SGAR usage, of four different rodenticides at different raptor life stages. The risk to raptors was evaluated in reference to sublethal and lethal effect thresholds used by regulators. Our model suggests exposure to Brodifacoum exceeds the threshold for lethal and sublethal effects. Breeding adults and nestlings are at risk of sublethal effects from Difethialone and the mixture of Bromadiolone and Difenacoum exposure. This is concerning because Brodifacoum and Difethialone usage seems to be rising globally due to increased resistance of rodents to other SGARs. Difethialone represents cumulative risk in scenarios previously not a risk, reaching the threshold in a week Avoiding SGAR usage during the raptor breeding season would reduce the likelihood and impact of secondary SGAR poisoning. Our framework can be used to assess different exposure scenarios for SGARs and raptors in ecological meaningful contexts to guide SGAR usage and regulation.

AB - Globally, populations of many raptor species are declining for reasons including exposure to chemical contaminants. Second Generation Anticoagulant Rodenticide (SGAR) residues are commonly found in the livers of raptors, indicating dietary exposure and potentially secondary poisoning. There is a gap in our understanding of SGAR exposure for raptors at different life stages and under different usage regimes. We develop a new modelling framework for non-target species to refine the commonly applied risk assessment using the common kestrel (Falco tinnunculus) as a case study. Our scenarios simulate high and low rodent consumption by raptors with high and low SGAR usage, of four different rodenticides at different raptor life stages. The risk to raptors was evaluated in reference to sublethal and lethal effect thresholds used by regulators. Our model suggests exposure to Brodifacoum exceeds the threshold for lethal and sublethal effects. Breeding adults and nestlings are at risk of sublethal effects from Difethialone and the mixture of Bromadiolone and Difenacoum exposure. This is concerning because Brodifacoum and Difethialone usage seems to be rising globally due to increased resistance of rodents to other SGARs. Difethialone represents cumulative risk in scenarios previously not a risk, reaching the threshold in a week Avoiding SGAR usage during the raptor breeding season would reduce the likelihood and impact of secondary SGAR poisoning. Our framework can be used to assess different exposure scenarios for SGARs and raptors in ecological meaningful contexts to guide SGAR usage and regulation.

KW - Rodenticides/toxicity

KW - Animals

KW - Anticoagulants/toxicity

KW - Raptors/physiology

KW - Risk Assessment

KW - 4-Hydroxycoumarins/toxicity

KW - Environmental Exposure/statistics & numerical data

KW - Environmental Pollutants

KW - Environmental Monitoring

U2 - 10.1016/j.scitotenv.2025.179903

DO - 10.1016/j.scitotenv.2025.179903

M3 - Article

C2 - 40582051

SN - 0048-9697

VL - 992

JO - Science of the Total Environment

JF - Science of the Total Environment

M1 - 179903

ER -