Is dietary mercury of neurotoxicological concern to wild polar bears ( Ursus maritimus)?
Abstract Polar bears ( Ursus maritimus ) are exposed to high concentrations of mercury because they are apex predators in the Arctic ecosystem. Although mercury is a potent neurotoxic heavy metal, it is not known whether current exposures are of neurotoxicological concern to polar bears. We tested t...
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crwiley:10.1897/08-251.1 2024-10-06T13:46:46+00:00 Is dietary mercury of neurotoxicological concern to wild polar bears ( Ursus maritimus)? Basu, Niladri Scheuhammer, Anton M. Sonne, Christian Letcher, Robert J. Born, Erik W. Dietz, Rune 2009 http://dx.doi.org/10.1897/08-251.1 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1897%2F08-251.1 https://setac.onlinelibrary.wiley.com/doi/pdf/10.1897/08-251.1 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Environmental Toxicology and Chemistry volume 28, issue 1, page 133-140 ISSN 0730-7268 1552-8618 journal-article 2009 crwiley https://doi.org/10.1897/08-251.1 2024-09-11T04:17:39Z Abstract Polar bears ( Ursus maritimus ) are exposed to high concentrations of mercury because they are apex predators in the Arctic ecosystem. Although mercury is a potent neurotoxic heavy metal, it is not known whether current exposures are of neurotoxicological concern to polar bears. We tested the hypotheses that polar bears accumulate levels of mercury in their brains that exceed the estimated lowest observable adverse effect level (20 μg/g dry wt) for mammalian wildlife and that such exposures are associated with subtle neurological damage, as determined by measuring neurochemical biomarkers previously shown to be disrupted by mercury in other high‐trophic wildlife. Brain stem (medulla oblongata) tissues from 82 polar bears subsistence hunted in East Greenland were studied. Despite surprisingly low levels of mercury in the brain stem region (total mercury = 0.36 ±0.12 μg/g dry wt), a significant negative correlation was measured between N ‐methyl‐D‐aspartate (NMDA) receptor levels and both total mercury ( r = —0.34, p < 0.01) and methylmercury ( r = —0.89, p < 0.05). No relationships were observed among mercury, selenium, and several other neurochemical biomarkers (dopamine‐2, gamma‐aminobutyric acid type A, muscarinic cholinergic, and nicotinic cholinergic receptors; cholinesterase and monoamine oxidase enzymes). These data show that East Greenland polar bears do not accumulate high levels of mercury in their brain stems. However, decreased levels of NMDA receptors could be one of the most sensitive indicators of mercury's subclinical and early effects. Article in Journal/Newspaper Arctic East Greenland Greenland Ursus maritimus Wiley Online Library Arctic Greenland Environmental Toxicology and Chemistry 28 1 133 |
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Wiley Online Library |
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English |
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Abstract Polar bears ( Ursus maritimus ) are exposed to high concentrations of mercury because they are apex predators in the Arctic ecosystem. Although mercury is a potent neurotoxic heavy metal, it is not known whether current exposures are of neurotoxicological concern to polar bears. We tested the hypotheses that polar bears accumulate levels of mercury in their brains that exceed the estimated lowest observable adverse effect level (20 μg/g dry wt) for mammalian wildlife and that such exposures are associated with subtle neurological damage, as determined by measuring neurochemical biomarkers previously shown to be disrupted by mercury in other high‐trophic wildlife. Brain stem (medulla oblongata) tissues from 82 polar bears subsistence hunted in East Greenland were studied. Despite surprisingly low levels of mercury in the brain stem region (total mercury = 0.36 ±0.12 μg/g dry wt), a significant negative correlation was measured between N ‐methyl‐D‐aspartate (NMDA) receptor levels and both total mercury ( r = —0.34, p < 0.01) and methylmercury ( r = —0.89, p < 0.05). No relationships were observed among mercury, selenium, and several other neurochemical biomarkers (dopamine‐2, gamma‐aminobutyric acid type A, muscarinic cholinergic, and nicotinic cholinergic receptors; cholinesterase and monoamine oxidase enzymes). These data show that East Greenland polar bears do not accumulate high levels of mercury in their brain stems. However, decreased levels of NMDA receptors could be one of the most sensitive indicators of mercury's subclinical and early effects. |
format |
Article in Journal/Newspaper |
author |
Basu, Niladri Scheuhammer, Anton M. Sonne, Christian Letcher, Robert J. Born, Erik W. Dietz, Rune |
spellingShingle |
Basu, Niladri Scheuhammer, Anton M. Sonne, Christian Letcher, Robert J. Born, Erik W. Dietz, Rune Is dietary mercury of neurotoxicological concern to wild polar bears ( Ursus maritimus)? |
author_facet |
Basu, Niladri Scheuhammer, Anton M. Sonne, Christian Letcher, Robert J. Born, Erik W. Dietz, Rune |
author_sort |
Basu, Niladri |
title |
Is dietary mercury of neurotoxicological concern to wild polar bears ( Ursus maritimus)? |
title_short |
Is dietary mercury of neurotoxicological concern to wild polar bears ( Ursus maritimus)? |
title_full |
Is dietary mercury of neurotoxicological concern to wild polar bears ( Ursus maritimus)? |
title_fullStr |
Is dietary mercury of neurotoxicological concern to wild polar bears ( Ursus maritimus)? |
title_full_unstemmed |
Is dietary mercury of neurotoxicological concern to wild polar bears ( Ursus maritimus)? |
title_sort |
is dietary mercury of neurotoxicological concern to wild polar bears ( ursus maritimus)? |
publisher |
Wiley |
publishDate |
2009 |
url |
http://dx.doi.org/10.1897/08-251.1 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1897%2F08-251.1 https://setac.onlinelibrary.wiley.com/doi/pdf/10.1897/08-251.1 |
geographic |
Arctic Greenland |
geographic_facet |
Arctic Greenland |
genre |
Arctic East Greenland Greenland Ursus maritimus |
genre_facet |
Arctic East Greenland Greenland Ursus maritimus |
op_source |
Environmental Toxicology and Chemistry volume 28, issue 1, page 133-140 ISSN 0730-7268 1552-8618 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1897/08-251.1 |
container_title |
Environmental Toxicology and Chemistry |
container_volume |
28 |
container_issue |
1 |
container_start_page |
133 |
_version_ |
1812175092881293312 |