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.

Heavy metals in flamingos (Phoenicopterus ruber) from Italian wetlands: the problem of ingestion of lead shot.

Waterbirds are exposed to many contaminants, including lead from ingestion of shot and fishing sinkers. Lead poisoning had never been reported in flamingos wintering in Italian wetlands. Our investigation stems from a case of four flamingos found dead in Tuscany in 2002 with numerous lead shot in their gizzards. We therefore considered other specimens found dead in different Italian wetlands. Many lead shot found in gizzards and lead tissue concentrations confirmed the hypothesis of lead poisoning in two of the seven specimens analysed: concentrations in liver, kidney, and bone were 361.3, 265.09, and 43.31mug/g d.w., respectively. Lead organotropism was typical of acute poisoning. Cadmium and mercury were also determined, and found to be in line with what little data are available on this species in the literature. Although Italy recently endorsed the African-Eurasian Waterbird Agreement (AEWA) prohibiting use of lead shot for hunting in wetlands, our results reveal a first case of lead shot poisoning in flamingos wintering in Italian wetlands. This evidence sounds a further warning of the problem of spent lead shot in countries where hunting in wetlands is not strictly regulated.

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 nondestructive biomarker suitable for situations in which destructive sampling of natural populations must be avoided, suggesting the implementation of this approach.