Chlorophacinone residues in mammalian prey at a black‐tailed prairie dog colony

Vyas, Nimish B.; Hulse, Craig S.; Rice, Clifford P.

doi:10.1002/etc.1968

Cited by 10 publications

(4 citation statements)

References 14 publications

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“…The levels of chlorophacinone residues in the livers of black‐tailed prairie dogs (0.06–8.4 mg kg −1 ) were similar to those reported for prairie dogs in another study (0.44–7.56 mg kg −1 ) . Compared with other species, the maximum residues from prairie dogs were between the maximum reported for laboratory rats (24.9 mg kg −1 ) in a lab study and those reported for Belding's ground squirrel ( Urocitellus beldingi ; 0.82 mg kg −1 ) and Microtus spp.…”

Section: Discussionsupporting

confidence: 79%

“…The residues were highest during 3–6 days post‐exposure, but declined sharply in subsequent days. A field study using Rozol bait found a similar sharp decline in residues in the livers of dead prairie dogs; however, residue analyses were not conducted until carcasses were first observed above ground ≥12 days post‐exposure . The residue levels on day 12 of this field study (

\overline{x}

∼ 3.4 mg kg −1 ) closely matched the levels we detected on day 5 (

\overline{x}

= 3.4 mg kg −1 ) post‐exposure.…”

Section: Discussionsupporting

confidence: 71%

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Retention time of chlorophacinone in black‐tailed prairie dogs informs secondary hazards from a prairie dog rodenticide bait

Witmer

Snow

Moulton

2015

Pest Management Science

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BACKGROUND: Secondary toxicity in mammals and birds that consume animals containing residues of anticoagulant rodenticides represents a persistent conflict between conservation, agriculture and environmental contamination. Chlorophacinone residues in black-tailed prairie dogs (Cynomys ludovicianus) represent a secondary exposure hazard to predatory and scavenging avian and mammalian species in the Central Plains of the United States, especially considering efforts to re-establish black-footed ferrets (Mustela nigripes). Rozol ® Prairie Dog Bait (chlorophacinone 0.005%) is registered to control black-tailed prairie dogs in ten states throughout the midwestern and western United States. RESULTS:We fed Rozol Prairie Dog Bait to captive black-tailed prairie dogs for 2 days and analyzed their livers and whole bodies (without livers) for chlorophacinone residue on days 3, 5, 7, 9, 11, 14, 18 and 27 post-exposure. We found the greatest levels of residues in livers (x = 5.499 mg kg −1 ) and whole bodies (x = 1.281 mg kg −1 ) on day 3. Residues in both tissues declined rapidly over time, with estimated half-lives of approximately 6 days post-exposure. However, a risk assessment of secondary toxicity to non-target mammals indicated acute risks for mammalian species up to 27 days post-exposure and negligible risks for birds. CONCLUSION:The results suggest that the greatest risk of secondary toxicity occurs ≤14 days post-application of Rozol Prairie Dog Bait and declines thereafter. This corresponds to the time when chlorophacinone residues are high, and prairie dogs exhibit signs of intoxication and are perhaps most susceptible to predation and scavenging. These results confirm that Rozol Prairie Dog Bait should not be used in areas where black-footed ferrets or other sensitive species occur. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

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Section: Discussionsupporting

confidence: 79%

\overline{x}

∼ 3.4 mg kg −1 ) closely matched the levels we detected on day 5 (

\overline{x}

= 3.4 mg kg −1 ) post‐exposure.…”

Section: Discussionsupporting

confidence: 71%

Retention time of chlorophacinone in black‐tailed prairie dogs informs secondary hazards from a prairie dog rodenticide bait

Witmer

Snow

Moulton

2015

Pest Management Science

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“…Using hematocrit and blood clotting times as endpoints, dietary exposure of captive kestrels to environmentally realistic concentrations (Merson et al 1984, Primus et al 2001, Ramey et al 2007, Vyas et al 2012, Pitt et al 2015, Shore and Coeurdassier 2018 of the FGAR chlorophacinone or the SGAR brodifacoum did not affect sensitivity to a subsequent low-level dietary dose of chlorophacinone. Based upon previous studies in kestrels (Rattner et al 2015), a seven-day, no-choice dietary exposure to 1.5 µg chlorophacinone/g-ww or to 0.5 µg brodifacoum/g ww evokes coagulopathy and results in substantial hepatic residues of these ARs.…”

Section: Discussionmentioning

confidence: 99%

Is Sensitivity to Anticoagulant Rodenticides Affected by Repeated Exposure in Hawks?

Rattner¹,

Lazarus²,

Bean³

et al. 2018

vertebrate_pest_conference

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A seminal question in wildlife toxicology is whether exposure to an environmental contaminant, in particular a secondgeneration anticoagulant rodenticide, can evoke subtle long lasting effects on body condition, physiological function and survival. Many reports indicate that non-target predators often carry residues of several rodenticides, which is indicative of multiple exposures. An often-cited study in laboratory rats demonstrated that exposure to the second-generation anticoagulant rodenticide brodifacoum prolongs blood clotting time for a few days, but weeks later when rats were re-exposed to the first-generation anticoagulant rodenticide warfarin, coagulopathy was more pronounced in brodifacoum-treated rats than naïve rats exposed to warfarin. To further investigate this phenomenon, American kestrels were fed environmentally realistic doses of chlorophacinone or brodifacoum for a week, and following a week-long recovery period, birds were then challenged with a low-level dietary dose of chlorophacinone. In the present study, neither hematocrit nor clotting time (prothrombin time, Russell's viper venom time) were differentially affected in sequentially exposed kestrels compared to naïve birds fed low-level dietary dose of chlorophacinone. While the present findings do not reveal lasting effects of anticoagulant exposure on blood clotting ability, findings in laboratory rats and other species have demonstrated such effects on blood clotting, and even other molecular pathways associated with immune function and xenobiotic metabolism. Additional studies using an environmentally realistic route of exposure and dose are underway to further test this hypothesis.

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“…A complicating factor is that some of the reported AR residue values (Primus et al ; Ramey et al ; Pitt et al ) were derived from carcass samples from which liver had been removed. This may underestimate exposure because brodifacoum and chlorophacinone concentrations in liver of small mammal prey can be much greater than in the rest of the body (e.g., Vyas et al ; Shore and Coeurdassier ). Moreover, hawk species for which the kestrel may be the most appropriate model do not ingest entire mammalian prey but feed selectively on liver, brain, muscle, and some organs.…”

Section: Methodsmentioning

confidence: 99%

Brodifacoum Toxicity in American Kestrels (Falco sparverius) with Evidence of Increased Hazard on Subsequent Anticoagulant Rodenticide Exposure

Rattner

Volker

Lankton

et al. 2020

Enviro Toxic and Chemistry

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A seminal question in ecotoxicology is the extent to which contaminant exposure evokes prolonged effects on physiological function and fitness. A series of studies were undertaken with American kestrels ingesting environmentally realistic concentrations of the second-generation anticoagulant rodenticide (SGAR) brodifacoum. Kestrels fed brodifacoum at 0.3, 1.0, or 3.0 µg/g diet wet weight for 7 d exhibited dose-dependent hemorrhage, histopathological lesions, and coagulopathy (prolonged prothrombin and Russell's viper venom times). Following termination of a 7-d exposure to 0.5 µg brodifacoum/g diet, prolonged blood clotting time returned to baseline values within 1 wk, but brodifacoum residues in liver and kidney persisted during the 28-d recovery period (terminal half-life estimates >50 d). To examine the hazard of sequential anticoagulant rodenticide (AR) exposure, kestrels were exposed to either the first-generation AR chlorophacinone (1.5 µg/g diet) or the SGAR brodifacoum (0.5 µg/g diet) for 7 d and, following a recovery period, challenged with a low dose of chlorophacinone (0.75 µg/g diet) for 7 d. In brodifacoum-exposed kestrels, the challenge exposure clearly prolonged prothrombin time compared to naive controls and kestrels previously exposed to chlorophacinone. These data provide evidence that the SGAR brodifacoum may have prolonged effects that increase the toxicity of subsequent AR exposure. Because free-ranging predatory and scavenging wildlife are often repeatedly exposed to ARs, such protracted toxicological effects need to be considered in hazard and risk assessments. Environ Toxicol Chem 2020;39:468-481. © 2019 SETAC

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Chlorophacinone residues in mammalian prey at a black‐tailed prairie dog colony

Cited by 10 publications

References 14 publications

Retention time of chlorophacinone in black‐tailed prairie dogs informs secondary hazards from a prairie dog rodenticide bait

Retention time of chlorophacinone in black‐tailed prairie dogs informs secondary hazards from a prairie dog rodenticide bait

Is Sensitivity to Anticoagulant Rodenticides Affected by Repeated Exposure in Hawks?

Brodifacoum Toxicity in American Kestrels (Falco sparverius) with Evidence of Increased Hazard on Subsequent Anticoagulant Rodenticide Exposure

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