Comparison of Hepatic and Nephric Total Mercury Concentrations Between Feral and Ranch American Mink (Neovison vison) from Northwestern Poland

For many years the American mink (Neovison vison) has been used in North America (where it originates from) as a sensitive indirect bioindicator in assessing the degree of mercury (Hg) contamination in terrestrial ecosystems. The aim of this paper was the determination of total concentrations of Hg in the liver and kidneys of feral and ranch mink from the Warta Mouth National Park (WMNP) and from farms located in northwestern Poland, for comparison with similar data on American mink from North America. In road-killed feral mink from the WMNP, the mean concentrations were 11.8 and 14.1 mg/kg dry weight in the liver and kidney, respectively. Mean Hg concentrations in feral mink were from 240 to 90 times higher in these two respective tissues than in ranch mink. The feral mink from northwestern Poland had concentrations of hepatic and nephric Hg similar to the highest concentrations that have been recorded over the past several decades in wild American mink from certain areas of Canada and the USA

Brains of Native and Alien Mesocarnivores in Biomonitoring of Toxic Metals in Europe.

Mercury (Hg), lead (Pb) and cadmium (Cd) are involved in mammalian brain damage. However, little is known about Pb and Cd brain levels in wildlife that reflect the geochemical background. The aims of the study include the estimation of Hg, Pb and Cd concentrations, and the determination of relationships between these elements in the brains of 94 mesocarnivores. Road-killed or hunted animals were obtained from north-western Poland near the Polish-German border. The investigation covered the native Eurasian otter Lutra lutra, badger Meles meles, pine marten Martes martes, beech marten M. foina, European polecat Mustela putorius, red fox Vulpes vulpes, and alien species: feral and ranch American mink Neovison vison, raccoon Procyon lotor and raccoon dog Nyctereutes procyonoides. Depending on the diet and environmental pollution, the carnivore brains accumulated toxic metals in varying amounts. The highest median Hg levels (in mg/kg dry weight, dw) were found in the piscivorous Eurasian otter and feral mink (2.44 and 3.96), Pb in the omnivorous raccoon (0.47), while Cd in minks (~0.06). We indicated that Pb-based ammunition is a significant source of the element in scavengers from hunting area, and we also found a significant correlation between Pb and Cd levels in the fox brain. Finally, this study is the first to suggest background levels for brain Pb and Cd in mesocarnivores (<0.50 and <0.04 mg/kg dw, respectively)

Analysis of data on raccoon, found frequently in the WMNP, shows a significant relationship between brain Hg levels and body weight in this partly piscivorous species.

<p>Analysis of data on raccoon, found frequently in the WMNP, shows a significant relationship between brain Hg levels and body weight in this partly piscivorous species.</p

General information on the studied mesocarnivores (VLub, Lubuskie Voivodship; VZach, Voivodship Zachodniopomorskie; n, number; PL, Poland: status and trend population; EU, European Union: status according to Habitats Directive 92/43/EEC–Annex II.

<p>Species of community interest whose conservation requires the designation of special areas of conservation, Annex IV. Species of community interest in need of strict protection. Annex V. Species of community interest whose taking in the wild and exploitation may be subject to management measures).</p

Krey et al. [83] have recently conducted extensive analysis of the brain Hg levels in a multi-species group of mammals, indicating relationships between various Hg concentrations and neurological changes.

<p>In our study, we used that analysis to classify the animals we studied based on brain Hg levels. Most often, the highest Hg levels, indicating neurobehavioural and/or neurochemical changes, were observed in mammals with some share of fish in their diets. These were minks, otters and raccoons, many of which were killed on roads.</p

The area where the animals were collected is located at the Polish-German border.

<p>Winds in this part of Europe are mostly from south-west and organisms living in the area are exposed to emissions from both local and distant sources.</p

For several decades, this part of Europe has seen an increasing number of alien carnivores (raccoon, raccoon dog, American mink).

<p>Together with native species, they constitute a group of mammals with diverse food preferences, which is especially reflected in Hg levels.</p

Analytical results for content (mg/kg dw) of mercury (AMA 254) as well as cadmium and lead (Perkin–Elmer Optima 2000 DV) in certified reference materials DOLT-4 Dogfish and NIST 8414 Bovine Muscle Powder.

<p>Analytical results for content (mg/kg dw) of mercury (AMA 254) as well as cadmium and lead (Perkin–Elmer Optima 2000 DV) in certified reference materials DOLT-4 Dogfish and NIST 8414 Bovine Muscle Powder.</p

Comparison of total mercury, lead and cadmium concentrations (mg/kg) in the brains of wild and domesticated carnivore species (T, terrestrial; SA, semiaquatic; n, number; AM, arithmetic mean; SD, standard deviation; ND, not detected; the original levels expressed in wet weight are converted to dry weight using the 4.3 multiplier and given in brackets).

<p>Comparison of total mercury, lead and cadmium concentrations (mg/kg) in the brains of wild and domesticated carnivore species (T, terrestrial; SA, semiaquatic; n, number; AM, arithmetic mean; SD, standard deviation; ND, not detected; the original levels expressed in wet weight are converted to dry weight using the 4.3 multiplier and given in brackets).</p