Deer exposed to exceptionally high concentrations of lead near the Continental Mine in Idaho, USA.
Abstract: Habitat surrounding the inactive Continental Mine in northern Idaho, USA, supports bear (Ursus arctos, Ursus americanus), moose (Alces alces), elk (Cervus elaphus), woodland caribou (Rangifer tarandus caribou), and abundant mule (Odocoileus hemionus) and white-tailed deer (Odocoileus virginianus). Tailings on the mining site were capped and remediated in 2003 to reduce environmental exposure of surrounding soil and sediments of Blue Joe Creek, downslope of the mine. Before capping, the mean Pb concentration in deer pellets collected on-site was 920 mg/kg of Pb (dry wt). This exposure, if chronic, would be comparable to an exposure that could be lethal to cattle or horses. Surprisingly, the mean pellet Pb concentration of 950 mg/kg in 2004 was as high as it was before remediation, and it was related to a high rate of soil ingestion. Mean soil content of the pellets collected from the capped site in 2004 was 22% dry weight, estimated from the acid-insoluble ash, a marker of soil ingestion. Clumps of sand and bits of rock were observed inside some of the pellets, and Pb concentrations in the pellets were correlated (p < 0.05) with soil content. Although terrestrial risk assessments generally estimate exposure from diets and from incidentally ingested soil. the deer at this site were directly ingesting contaminated soil or mining waste. The mean Pb concentration of this ingested soil was estimated as 6,700 mg/kg and the maximum as 25,000 mg/kg, well above the Pb concentrations measured in the remediated cap. The deer seemed to be ingesting soil or mining waste from one or more small but highly contaminated sources located beyond the remediated cap.
Publication Date: 2007-05-25 PubMed ID: 17521153DOI: 10.1897/06-304r.1Google Scholar: Lookup
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- Journal Article
- Research Support
- U.S. Gov't
- Non-P.H.S.
Summary
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This study examines the elevated lead concentrations found in deer in Idaho, USA, which appear to be associated with the ingestion of contaminated soil or mining waste from an inactive mine nearby, despite remediation efforts.
Background and Aim
- Several species of deer, bear, moose, elk, and caribou inhabit the area around the closed Continental Mine in northern Idaho, USA.
- This research aimed to understand the cause of the high lead (Pb) concentrations observed in these animals, particularly the deer, even after the mine’s tailings had been capped and remediated in 2003.
Pre-remediation Lead Concentrations
- Before the remediation efforts, the concentration of lead in deer pellets collected on the mine site was tracked, and the mean lead concentration was 920 mg/kg of lead (Pb) on a dry weight basis.
- This level of exposure, if sustained, could potentially be lethal to cattle or horses.
Post-remediation Findings
- Despite the aforementioned remediation efforts, the mean lead concentration in deer pellets remained remarkably high at 950 mg/kg, confirming that the deer were still being exposed to high levels of lead.
- Researchers suggested that the deer were consuming a significant amount of soil, as they found an average soil content of 22% by dry weight in the deer pellets collected.
- Unusually, small clumps of sand and bits of rock were also found within some of the deer pellets, suggesting direct ingestion of contaminated soil or mining waste.
Correlation between Lead Concentrations and Soil Ingestion
- A statistical correlation was established between lead concentrations in the deer pellets and the amount of soil found in the pellets, which substantiates the theory of direct ingestion of contaminated soil or mining waste.
- The mean lead concentration of the soil ingested by the deer was 6,700 mg/kg, with a maximum concentration reaching up to 25,000 mg/kg, significantly higher than the lead concentrations measured in the remediated cap at the mining site.
- These findings suggest that the deer are likely to be consuming contaminated soil or mining waste from small, highly contaminated sources located beyond the remediated area.
Cite This Article
APA
Beyer WN, Gaston G, Brazzle R, O'Connell AF, Audet DJ.
(2007).
Deer exposed to exceptionally high concentrations of lead near the Continental Mine in Idaho, USA.
Environ Toxicol Chem, 26(5), 1040-1046.
https://doi.org/10.1897/06-304r.1 Publication
Researcher Affiliations
- U.S. Geological Survey, Patuxent Wildlife Research Center, BARC East, Building 308, 10300 Baltimore Avenue, Beltsville, Maryland 20705, USA. nbeyer@usgs.gov
MeSH Terms
- Animals
- Animals, Wild
- Cattle
- Deer
- Environmental Exposure
- Geography
- Horses
- Idaho
- Industrial Waste
- Lead / analysis
- Lead / metabolism
- Lead / toxicity
- Mining
- Soil Pollutants / analysis
- Soil Pollutants / metabolism
- Soil Pollutants / toxicity
Citations
This article has been cited 2 times.- Vukšić N, Šperanda M, Lončarić Z, Đidara M, Ludek E, Budor I. The effect of dietary selenium addition on the concentrations of heavy metals in the tissues of fallow deer (Dama dama L.) in Croatia. Environ Sci Pollut Res Int 2018 Apr;25(11):11023-11033.
- Bilandzić N, Sedak M, Dokić M, Simić B. Wild boar tissue levels of cadmium, lead and mercury in seven regions of continental Croatia. Bull Environ Contam Toxicol 2010 Jun;84(6):738-43.
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