Lead exposure in American black bears increases with age and big game harvest density

Brown, Ludovick; Rosabal, Maikel; Dussault, Christian; Arnemo, Jon M.; Fuchs, Boris; Zedrosser, Andreas; Pelletier, Fanie

doi:10.1016/j.envpol.2022.120427

Cited by 12 publications

(13 citation statements)

References 59 publications

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“…This is a high enough discrepancy to suggest a real difference between these values even when accounting for limited accuracy of the XRF analysis. This result indicates support for the hypothesis that devils living in modified landscapes subjected to regular culling may be at elevated risk of lead contamination compared to devil populations in unmodified habitats (or at least those from urban areas with minimal shooting activity), as has been found in some other mammalian non-specialist scavengers in areas where hunting occurs (Brown et al, 2022; Kelly et al, 2021). Notably, our study results came from only two sample populations with different locations and time periods, so the discrepancy could be due to other factors that we could not incorporate into the analysis.…”

Section: Discussionsupporting

confidence: 75%

“…Brown bears ( Ursus arctos ) did show elevated lead levels in this landscape, but lead levels did not increase during the hunting season (Rogers et al, 2012). In contrast, brown bears sampled in northern Europe have shown markedly elevated lead levels in blood and milk (Boesen et al, 2019), and lead levels in the teeth of Canadian black bears increase markedly during hunting seasons (Brown et al, 2022). It is clear that further research is required into risk factors for harmful lead exposure in free ranging mammalian species (Chiverton et al, 2022).…”

Section: Discussionmentioning

confidence: 99%

“…The exception to this trend has been studies of bears (Ursus spp.) in the Northern Hemisphere (Boesen et al, 2019;Brown et al, 2023Brown et al, , 2022Fuchs et al, 2021). One recent study from the Southern Hemisphere demonstrated harmful lead levels in an Australian marsupial species, the Tasmanian devil (Sarcophilus harrisii), when fed whole shot carcasses in captivity (Hivert et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

“…To our knowledge, all past studies of lead exposure in scavenging mammals have utilized invasive sampling via collection of blood (Boesen et al, 2019; Brown et al, 2023; Fuchs et al, 2021; Hivert et al, 2018; Rogers et al, 2012), teeth (Brown et al, 2022) or liver (Kelly et al, 2021). Recent reviews have highlighted the value of non-invasive sampling of heavy metal exposure in wild mammals (Jota Baptista et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

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Portable X-ray Fluorescence for Measuring Lead in the Hair of Wild Mammals

Jones¹,

Bengsen

Specht

et al. 2023

Preprint

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Lead (Pb) toxicity is a threat to scavenging wildlife across the globe. To allow inexpensive measurement of long-term lead exposure from archived wildlife tissues, portable X-ray fluorescence (XRF) devices have been optimized to measure lead concentrations in bone samples from avian species. In this study, we assessed portable XRF for hair lead measurement in an Australian mammalian scavenger, the threatened Tasmanian devil (Sarcophilus harrisii). We attempted to first validate the method by analysing relatively large (~1.0 g) hair samples from 39 deceased animals initially with XRF, and then with inductively coupled plasma mass spectrometry (ICP-MS) (validation study). We then measured lead concentrations via XRF only in a further 61 hair samples taken from live devils trapped in a plantation forestry landscape, where devils may scavenge on browsing marsupials that are regularly culled using lead ammunition (plantation study). Portable XRF hair lead measurement demonstrated a positive correlation with ICP-MS results (R2 = 0.95), although the relationship was weak at low lead concentrations. In the validation study, 95% of sampled Tasmanian devils had relatively low lead levels (≤ 3 mg/kg), but the remaining two animals showed considerably elevated lead levels (> 15 mg/kg), suggesting that harmful long-term lead exposure can occur in this species. In the plantation study, lead levels were comparable to those found in the hair of mammals in other studies, though a higher proportion (11%) of devils showed levels > 3 mg/kg than in the validation study, suggesting devils may have higher exposure to lead in a landscape subjected to regular culling of browsing mammals. Our results suggests that portable XRF is a promising emerging technology, and after some refinement, may allow non-invasive real-time measurement of lead concentrations in the hair of mammals.

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Section: Discussionsupporting

confidence: 75%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Portable X-ray Fluorescence for Measuring Lead in the Hair of Wild Mammals

Jones¹,

Bengsen

Specht

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…[7][8][9] While bird species have been the focus of most lead ecotoxicology research, there is growing recognition on the effects of lead exposure on wild mammalian scavengers. 10 The majority of studies in this field have assessed eutherian carnivores from the Northern Hemisphere, particularly brown bears (Ursus arctos), [11][12][13][14] as well as black bears (Ursus americanus), 13,15 grey wolves (Canis lupus), 13,16 and cougars (Puma concolor). 13 There is also concern for potential impacts on other species for which regular scavenging occurs but lead exposure levels are yet to be quantified, such as Iberian lynx (Lynx pardinus) 17 and dingoes (Canis familiaris / Canis dingo).…”

mentioning

confidence: 99%

Further investigation of lead exposure as a potential threatening process for a scavenging marsupial species

Hutchinson,

Jones,

Pay

et al. 2023

Aust Veterinary J

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There is a growing recognition of the harmful effects of lead exposure on avian and mammalian scavengers. This can lead to both lethal and non‐lethal effects which may negatively impact wildlife populations. Our objective was to assess medium‐term lead exposure in wild Tasmanian devils (Sarcophilus harrisii). Frozen liver samples (n = 41), opportunistically collected in 2017–2022, were analysed using inductively coupled plasma mass spectrometry (ICP‐MS) to determine liver lead concentrations. These results were then used to calculate the proportion of animals with elevated lead levels (>5 mg/kg dry weight) and examine the role of explanatory variables that may have influenced the results. The majority of samples analysed were from the south‐east corner of Tasmania, within 50 km of Hobart. No Tasmanian devil samples were found to have elevated lead levels. The median liver lead concentration was 0.17 mg/kg (range 0.05–1.32 mg/kg). Female devils were found to have significantly higher liver lead concentrations than males (P = 0.013), which was likely related to lactation, but other variables (age, location, body mass) were not significant. These results suggest that wild Tasmanian devil populations currently show minimal medium‐term evidence of exposure to lead pollution, although samples were concentrated in peri‐urban areas. The results provide a baseline level which can be used to assess the impact of any future changes in lead use in Tasmania. Furthermore, these data can be used as a comparison for lead exposure studies in other mammalian scavengers, including other carnivorous marsupial species.

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Vulnerability to lead toxicosis and bioindicator utility of deer scavengers in New York

Eleftheriou,

Hynes,

Clark

et al. 2024

J Wildl Manag

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Lead (Pb) is a heavy metal with no clear biological benefit that is toxic to wildlife and humans. Although Pb has been banned from several consumer products, it is not regulated in ammunition for big‐game hunting (e.g., cervids) in New York, USA. Wildlife species that scavenge remains of game harvested with Pb ammunition can be exposed to bullet fragments through ingestion and potentially develop toxicosis. To make evidence‐based decisions for reducing risk from bullet‐derived Pb, we first empirically identified avian and mammalian scavengers of white‐tailed deer (Odocoileus virginianus) remains in New York through an online survey during July‐August 2023, where community members submitted images of scavengers from game cameras. We conducted species vulnerability and utility assessments using published evidence and pre‐existing frameworks. Despite inherent limitations, we documented an extensive array of avian (n = 17) and mammalian (n = 14) scavengers. We estimated bald eagles (Haliaeetus leucocephalus) and golden eagles (Aquila chrysaetos) as most vulnerable to Pb toxicosis, followed collectively by American goshawks (Accipiter atricapillus), American crows (Corvus brachyrhynchos), and common ravens (C. corax). We also determined bald eagles to be best‐suited as bioindicators of bullet‐derived Pb, followed by American goshawks. Red‐tailed hawks (Buteo jamaicensis) and great horned owls (Bubo virginianus) equally ranked third. Integrating vulnerability and utility assessments point to bald eagles as the most vulnerable scavengers to Pb toxicosis and best‐suited bioindicators of bullet‐derived Pb. Because regulation of Pb ammunition for big‐game hunting is an ongoing socio‐political issue, wildlife managers and conservationists can address health risks through monitoring species vulnerable to toxicosis and instituting surveillance programs using the most effective bioindicators.

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Lead exposure in American black bears increases with age and big game harvest density

Cited by 12 publications

References 59 publications

Portable X-ray Fluorescence for Measuring Lead in the Hair of Wild Mammals

Portable X-ray Fluorescence for Measuring Lead in the Hair of Wild Mammals

Further investigation of lead exposure as a potential threatening process for a scavenging marsupial species

Vulnerability to lead toxicosis and bioindicator utility of deer scavengers in New York

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