Total mercury in hair of polar bears (Ursus maritimus) from Greenland and Svalbard

Concentrations (ppm = ug/g dry weight) of total mercury (Hg) were determined in hair of polar bears (Ursus maritimus) from northwestern Greenland (N = 22; period of sampling: 1978-1989), eastern Greenland (N = 44: 1984-1989) and Svalbard (N = 31; 1980). For subadults (2-6 years of life), adults (7-10 years). and old bears (>10 years), concentrations of total Hg in hair were not found to be dependent on age or sex. A decreasing trend in Hg concentrations was found from west to east. The mean concentrations of total Hg in hair (cubs of the year and yearlings excluded) were: northwestern Greenland, x = 8.38 ppm (min.-max.: 4.71-14.19 ppm. N = 21); eastern Greenland: x = 4.58 ppm (min.-max.: 2.50-8.83 ppm. N = 41); and Svalbard, x = 1.98 ppm (min.-max.: 1.02-4.55 ppm, N = 29). Concentrations found in northwestern Greenland were similar to those reported by others from the hair of polar bears sampled within management zone F of the eastern Canadian High Arctic. Concentrations of total Hg in polar bear hair from eastern Greenland were similar to concentrations found by others in contemporary (1988) material collected during spring in western Svalbard. However, the mean concentration of total Hg in the 1980 Svalbard material, which was collected during July-September, was significantly lower than concentrations found in samples taken during late winter and spring in eastern Greenland and at Svalbard, respectively. Presumably the relatively low concentrations found in the 1980 Svalbard sample arc attributable to the period of moult and hence a larger proportion of newly grown hair in the individual samples. In a subsample consisting of internal tissues from 19 polar bears from eastern Greenland (1984-1987), concentrations of total Hg in hair correlated positively with concentrations of total Hg (wet weight) in muscle (N = 6), liver (N = 19) and kidney (N = 19) tissue. For liver and kidney tissue these relationships were statistically significant

What are the toxicological effects of mercury in Arctic biota?

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 of mercury recorded in brain tissue with associated signs of neurochemical effects. Evidence of increasing concentrations in mercury in some biota in Arctic Canada and Greenland is therefore a concern with respect to ecosystem health

Review: Porphyrins as biomarkers for hazard assessment of bird populations: Destructive and non-destructive use

In this review the biochemical, metabolic and toxicological significance of porphyrins in birds is examined, and their use as biomarkers of exposure to xenobiotics and heavy metals is explored. Laboratory studies pinpointing the main classes of compounds that alter porphyrin profiles are described, as well as those which defined the resulting porphyrin profiles and target organs. Field studies in which the biomarker was validated on natural populations of several species of birds are then reviewed. We finally illustrate their potential as a non-destructive biomarker suitable for situations in which destructive sampling of natural populations must be avoided, suggesting the implementation of this approach

The reproductive cycle and the glochidium of Anodonta cygnea L. from Lago Trasimeno (Central Italy)

The different phases of the biological cycle of Anodonta cygnea L. living in lake Trasimeno (Central Italy) are described in the present paper. Researches have been carried out on histological sections of germinal tissues and gills of specimens of both sexes sacrificed every month and verified by following the course of the parasitic phase of life of glochidia on the fish of the lake. Moreover, the various species of fish heavily infested by glochidia have been identified and the glochidium infestation frequency has been determined. The structure of the glochidium shell has been studied with the scanning microscope for a better understanding of the mechanism of attachment to fish and to collect more information in order to compare the species of Anodonta from lake Trasimeno with those of other parts of Europe