Risks and Hazards of Rodenticide to Non-raptor Birds

Incident data can support risk assessments by providing evidence of adverse effects of rodenticides to birds following operational applications. Traditionally, field monitoring for rodenticide incidents has focused primarily on raptors. However, nonraptor birds may also be poisoned (rodenticide exposure resulting in adverse effects including mortality) by rodenticides through consumption of the rodenticide bait and contaminated prey. I conducted a literature search canvassing 12 government and scholarly databases for rodenticide incidents (evidence of exposure to a rodenticide, adverse effects, or exposure to placebo baits) involving non-raptor birds. I used the search terms ‘rodenticide’ and ‘birds’ and from these results, I excluded entries of raptor incidents, laboratory toxicology studies, duplicate records, and unpublished literature (except for entries in the US Environmental Protection Agency’s Incident Data System). I ended up with 641 non-raptor rodenticide incident records spanning the years 1931 to 2016. The incident records included 17 orders, 58 families, and 190 non-raptor bird species ranging from emus (Dromaius novaehollandiae) to songbirds (Order Passeriformes). Nineteen anticoagulant and non- anticoagulant rodenticide active ingredients were associated with the incidents. Rodenticide formulations including bait blocks, cereal based pellets, carrot baits, pastes and jams, liquids, and loose grain baits following above-ground, below-ground, in-bait stations, and in-meat applications have results in non-raptor incidents either through direct ingestion of the rodenticide or via contaminated invertebrate and vertebrate prey. The availability of incident records affected the numbers of incidents in this review. The availability is in turn is affected by the infrastructure for monitoring and reporting incidents. For example, although rodenticides are used worldwide, I found non-raptor incident records from only 15 countries. I compared the number of incidents and species detected by surveillance method (passive vs. active surveillance) and by the purpose of application (for ecological restoration vs for human welfare). More incidents were reported from passive surveillance and following applications for human welfare but a significantly greater number of species were detected in proportion to the number of incidents found through active surveillance and following applications for ecological restoration. In conclusion:1) A broad diversity of non-raptor species are affected by rodenticides with a variety of modes of action, formulations, and application methods; 2) Surveillance method and the purpose of application can influence the quantity and quality of incident data; 3) The lack of evidence does not imply the lack of hazard but signifies poor infrastructure for monitoring and reporting non-raptor avian incidents; 4) Awareness of the breadth of species diversity of non-raptor bird poisonings from rodenticides may increase the incentive for monitoring and reporting them and this in turn can strengthen the predictions of harm characterized by risk assessments

Critique on the Use of the Standardized Avian Acute Oral Toxicity Test for First Generation Anticoagulant Rodenticides

Avian risk assessments for rodenticides are often driven by the results of standardized acute oral toxicity tests without regards to a toxicant’s mode of action and time course of adverse effects. First generation anticoagulant rodenticides (FGARs) generally require multiple feedings over several days to achieve a threshold concentration in tissue and cause adverse effects. This exposure regimen is much different than that used in the standardized acute oral toxicity test methodology. Median lethal dose values derived from standardized acute oral toxicity tests underestimate the environmental hazard and risk of FGARs. Caution is warranted when FGAR toxicity, physiological effects, and pharmacokinetics derived from standardized acute oral toxicity testing are used for forensic confirmation of the cause of death in avian mortality incidents and when characterizing FGARs’ risks to free-ranging birds

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Risks and Hazards of Rodenticide to Non-raptor Birds (Abstract)

Incident data can support risk assessments by providing evidence of adverse effects of rodenticides to birds following operational applications. Traditionally, field monitoring for rodenticide incidents has focused primarily on raptors. However, non-raptor birds may also be poisoned (rodenticide exposure resulting in adverse effects including mortality) by rodenticides through consumption of the rodenticide bait and contaminated prey. I conducted a literature search canvassing 12 government and scholarly databases for rodenticide incidents (evidence of exposure to a rodenticide, adverse effects, or exposure to placebo baits) involving non-raptor birds. I used the search terms ‘rodenticide’ and ‘birds’ and from these results, I excluded entries of raptor incidents, laboratory toxicology studies, duplicate records, and unpublished literature (except for entries in the US Environmental Protection Agency’s Incident Data System). I ended up with 641 non-raptor rodenticide incident records spanning the years 1931 to 2016. The incident records included 17 orders, 58 families, and 190 non-raptor bird species ranging from emus (Dromaius novaehollandiae) to songbirds (Order Passeriformes). Nineteen anticoagulant and non- anticoagulant rodenticide active ingredients were associated with the incidents. Rodenticide formulations including bait blocks, cereal based pellets, carrot baits, pastes and jams, liquids, and loose grain baits following above-ground, below-ground, in-bait stations, and in-meat applications have results in non-raptor incidents either through direct ingestion of the rodenticide or via contaminated invertebrate and vertebrate prey. The availability of incident records affected the numbers of incidents in this review. The availability is in turn is affected by the infrastructure for monitoring and reporting incidents. For example, although rodenticides are used worldwide, I found non-raptor incident records from only 15 countries. I compared the number of incidents and species detected by surveillance method (passive vs. active surveillance) and by the purpose of application (for ecological restoration vs for human welfare). More incidents were reported from passive surveillance and following applications for human welfare but a significantly greater number of species were detected in proportion to the number of incidents found through active surveillance and following applications for ecological restoration. In conclusion:1) A broad diversity of non-raptor species are affected by rodenticides with a variety of modes of action, formulations, and application methods; 2) Surveillance method and the purpose of application can influence the quantity and quality of incident data; 3) The lack of evidence does not imply the lack of hazard but signifies poor infrastructure for monitoring and reporting non-raptor avian incidents; 4) Awareness of the breadth of species diversity of non-raptor bird poisonings from rodenticides may increase the incentive for monitoring and reporting them and this in turn can strengthen the predictions of harm characterized by risk assessments

Acute oral toxicities of wildland fire control chemicals to birds

Wildland fire control chemicals are released into the environment by aerial and ground applications to manage rangeland, grassland, and forest fires. Acute oral 24 h median lethal dosages (LD50) for three fire retardants (Fire-Trol GTS-R™, Phos-Chek D-75F™, and Fire-Trol LCG-R™) and two Class A fire suppressant foams (Silv-Ex™ and Phos-Chek WD881™) were estimated for northern bobwhites, Colinus virginianus, American kestrels, Falco sparverius, and red-winged blackbirds, Agelaius phoeniceus. The LD50s of all chemicals for the bobwhites and red0winged blackbirds and for kestrels dosed with Phos-Chek WD881™ and Silv-Ex™ were above the predetermined 2000 mg chemical/kg body mass regulatory limit criteria for acute oral toxicity. The LD50s were not quantifiable for kestrels dosed with Fire-Trol GTS-R™, Phos-Chek D-75F™, and Fire-Trol LCG-R™ because of the number of birds which regurgitated the dosage. These chemicals appear to be of comparatively low order of acute oral toxicity to the avian species tested

The Influence of Study Species Selection on Estimates of Pesticide Exposure in Free-Ranging Birds

Field studies of pesticide effects on birds often utilize indicator species with the purpose of extrapolating to other avian taxa. Little guidance exists for choosing indicator species to monitor the presence and/or effects of contaminants that are labile in the environment or body, but are acutely toxic, such as anticholinesterase (anti-ChE) insecticides. Use of an indicator species that does not represent maximum exposure and/or effects could lead to inaccurate risk estimates. Our objective was to test the relevance of a priori selection of indicator species for a study on pesticide exposure to birds inhabiting fruit orchards. We used total plasma ChE activity and ChE reactivation to describe the variability in anti-ChE pesticide exposure among avian species in two conventionally managed fruit orchards. Of seven species included in statistical analyses, the less common species, chipping sparrow (Spizella passerina), showed the greatest percentage of exposed individuals and the greatest ChE depression, whereas the two most common species, American robins (Turdus migratorius) and gray catbirds (Dumatella carolinensis), did not show significant exposure. Due to their lower abundance, chipping sparrows would have been an unlikely choice for study. Our results show that selection of indicator species using traditionally accepted criteria such as abundance and ease of collection may not identify species that are at greatest risk. Our efforts also demonstrate the usefulness of conducting multiple-species pilot studies prior to initiating detailed studies on pesticide effects. A study such as ours can help focus research and resources on study species that are most appropriate

Evidence of Songbird Intoxication From Rozol Application at a Black-Tailed Prairie Dog Colony

Concerns about avian poisonings from anticoagulant rodenticides have traditionally focused on secondary poisoning of raptors exposed by feeding on contaminated mammalian prey. However, ground foraging songbirds can be directly poisoned from operational applications of the anticoagulant rodenticide RozolH (0.005% chlorophacinone, active ingredient) applied as a grain bait, at black-tailed prairie dog Cynomys ludovicianus colonies. A dead western meadowlark Sturnella neglecta recovered from the study prairie dog colony displayed hemorrhaging in brain and pectoral muscle tissue, and it contained chlorophacinone residue concentrations of 0.59 and 0.49 mg/g (wet weight) in the liver and intestinal contents, respectively. Chlorophacinone residues from two Rozol-colored songbird droppings found at the study colony were 0.09 and 0.46 mg/g (wet weight). The timing of the meadowlark mortality and the occurrence of discolored droppings show that songbird exposure and poisoning can occur weeks after a Rozol application

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts.The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that -80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAFPeer reviewe