Lactational transfer of mercury and polychlorinated biphenyls in polar bears

Knott, Katrina K.; Boyd, Daryle; Ylitalo, Gina M.; O’Hara, Todd M.

doi:10.1016/j.chemosphere.2012.02.053

Cited by 26 publications

(27 citation statements)

References 44 publications

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“…Hg intake was estimated at 0.33 to 6.51 μg/kg body weight/day, representing a daily Hg intake during the salmon consumption period of 0.04 to 1.42 mg ( Table 1). As a comparison, a tolerable daily intake (TDI) of 0.47 μg/kg body weight/day is considered safe for most of the human population, 49 meaning that 15 of the 16 coastal bears 50 . 13 On the basis of an average Hg level in wild chum, coho, pink, and sockeye salmon of 0.03 μg/g, 45,51 we estimated that wild BC grizzly bears are eating on average 13.4 ± 4.2 kg of salmon per day during the salmon spawning period.…”

Section: Environmental Science and Technologymentioning

confidence: 99%

Grizzly Bear Hair Reveals Toxic Exposure to Mercury through Salmon Consumption

Noël

Spence

Harris

et al. 2014

Environ. Sci. Technol.

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Mercury obtained from the diet accumulates in mammalian hair as it grows thus preserving a record of mercury intake over the growth period of a given hair segment. We adapted a microanalysis approach, using laser ablation inductively coupled plasma mass spectrometry, to characterize temporal changes in mercury exposure and uptake in wild and captive grizzly bears. Captive grizzlies fed diets containing known and varied amounts of mercury provided data to allow prediction of Hg ingestion rates in wild bears. Here, we show, for the first time, that 70% of the coastal grizzly bears sampled had Hg levels exceeding the neurochemical effect level proposed for polar bears. In a context where the international community is taking global actions to reduce Hg emissions through the "Minamata Convention on Mercury", our study provides valuable information on the exposure to mercury of these grizzly bears already under many threats.

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Section: Environmental Science and Technologymentioning

confidence: 99%

Grizzly Bear Hair Reveals Toxic Exposure to Mercury through Salmon Consumption

Noël

Spence

Harris

et al. 2014

Environ. Sci. Technol.

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“…Only blood Hg concentrations in Inuit women from Qaanaaq, northwestern Greenland, were similar to levels in polar bear. Blood Hg concentrations showed the lowest concentrations in western Hudson Bay and comparable concentrations between Alaska and East Greenland (Cardona-Marek et al, 2009;Dietz et al, 2000b (Knott et al, 2012). This is an important exposure route for Hg in young animals, and indicates an important elimination route for reproductive females (Knott et al, 2012).…”

Section: Blood Mercury In High Trophic Level Arctic Species In Comparmentioning

confidence: 99%

“…Blood Hg concentrations showed the lowest concentrations in western Hudson Bay and comparable concentrations between Alaska and East Greenland (Cardona-Marek et al, 2009;Dietz et al, 2000b (Knott et al, 2012). This is an important exposure route for Hg in young animals, and indicates an important elimination route for reproductive females (Knott et al, 2012). Concentrations of THg in adult polar bears ranged from 7 to 210 μg/L for blood, with adult females having a greater concentration of THg in hair than adult males, again indicating a cohort of concern exposed to higher Hg (i.e., the fetus and neonate) as reported by Cardona-Marek Fig.…”

Section: Blood Mercury In High Trophic Level Arctic Species In Comparmentioning

confidence: 99%

What are the toxicological effects of mercury in Arctic biota?

Dietz

Sonne

Basu

et al. 2013

Science of The Total Environment

311

202

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► Unpublished and published data were compiled for Arctic fish, birds, and mammals. ► These data were compared to available toxicological threshold limits. ► Toothed whales, polar bears, and some bird and fish species exceeded the limits. ► Increasing mercury concentrations are observed for some Arctic species. ► These exceeded thresholds and increasing Hg trends are of concern. a b s t r a c t a r t i c l e i n f o This review critically evaluates the available mercury (Hg) data in Arctic marine biota and the Inuit population against toxicity threshold values. In particular marine top predators exhibit concentrations of mercury in their tissues and organs that are believed to exceed thresholds for biological effects. Species whose concentrations exceed threshold values include the polar bears (Ursus maritimus), beluga whale (Delphinapterus leucas), pilot whale (Globicephala melas), hooded seal (Cystophora cristata), a few seabird species, and landlocked Arctic char (Salvelinus alpinus). Toothed whales appear to be one of the most vulnerable groups, with high concentrations Science of the Total Environment 443 (2013) [775][776][777][778][779][780][781][782][783][784][785][786][787][788][789][790]

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“…In addition to the 12% of papers that included some measure of reproduction, another 7% reported on contaminants in dependent young, but without any further statistical analysis (e.g., Dietz et al, 2000, Derocher et al, 2003. Dependent young differ in contaminant exposure and physiological variables such as hormone concentrations, not only from adults, but also due to sex and age (Bernhoft et al, 1997, Oskam et al, 2003, Oskam et al, 2004, Knott et al, 2012, Bechshoft et al, 2016a. Differences in physiological response to contaminants is expected between offspring life stages (e.g., when shifting from milk to solids) as well as between the sexes, as these differ in their endocrine, morphological, and overall physiological profile already at the fetal stage (Derocher et al, 2005, Hamlin and Guillette, 2011, Maekawa et al, 2014.…”

Section: R a F Tmentioning

confidence: 99%

On the integration of ecological and physiological variables in polar bear toxicology research: a systematic review

et al. 2018

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Ecotoxicology evolved as a scientific field as awareness of the unintended effects of anthropogenic pollutants in biota increased. Polar bears (Ursus maritimus) are often the focus of Arctic contaminant exposure studies because they are apex predators with high contaminant loads. While early studies focused on describing and quantifying pollutants, present-day polar bear toxicological papers often incorporate ecological variables. This systematic literature review investigates the ecological and physiological variables that have been integrated in such studies. The systematic literature search resulted in 207 papers, published between 1970 and 2016. Representation of each of the 19 polar bear subpopulations varied from 0 to 72 papers; East Greenland, Barents Sea, Southern Beaufort Sea, and Lancaster Sound had the most published research, with over 30 papers each. Samples were collected between 1881 and 2015, primarily from harvested bears (66%); most from the 1990s and 2000s. Adipose tissue, liver, and blood were the most common tissues examined, and mean number of bears analyzed per paper was 76 (range 1–691). Papers investigating temporal trends did so using a mean sample of 61 bears over a 6-year period.The frequency with which ecological and physiological variables were integrated into toxicological papers varied. Age and (or) sex was the only ecological variable(s) considered in 51% of papers. Further, a total of 37% of the papers included in the review investigated physiological effects in relation to contaminant concentrations. Of the papers, 98% dealt with contaminant exposure at the individual level, leaving population level effects largely unstudied. Solitary subadult and adult polar bears were included in 57% and 79% of the papers, respectively. Younger bears were included in fewer papers: yearlings in 20% and cubs-of-the-year in 13%. Only 12% of the papers examined reproduction relative to contaminants. Finally, body condition was included in 26% of the research papers, whereas variables related to polar bear diet were included in ≤9%. Based on our findings, we suggest future polar bear toxicology studies increase sample sizes, include more ecological variables, increase studies on family groups, and increase the applicability of studies to management and conservation by examining pollution effects on reproduction and survival.

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Lactational transfer of mercury and polychlorinated biphenyls in polar bears

Cited by 26 publications

References 44 publications

Grizzly Bear Hair Reveals Toxic Exposure to Mercury through Salmon Consumption

Grizzly Bear Hair Reveals Toxic Exposure to Mercury through Salmon Consumption

What are the toxicological effects of mercury in Arctic biota?

On the integration of ecological and physiological variables in polar bear toxicology research: a systematic review

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