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Fish mercury (Hg) concentrations have been measured over the last 30-40 years in all regions of Canada as part of various monitoring and research programs. Despite this large amount of data, only regional assessments of fish Hg trends and patterns have previously been attempted. The objective of this study was to assemble available freshwater fish Hg concentration data from all provinces and territories and identify national patterns. The Canadian Fish Mercury Database includes over 330 000 records representing 104 species of freshwater fish collected from over 5000 locations across Canada between 1967 and 2010. Analysis of the 28 most frequently occurring species (>1000 records) showed that the majority of variation in Hg concentrations (when normalized to a standard size) was accounted for by geographic location. Median Hg concentrations increased with trophic level (r = 0.40, p < 0.05), with the highest Hg concentrations found in piscivorous species such as walleye (Sander vitreus), northern pike (Esox lucius), and lake trout (Salvelinus namaycush). The Canadian Fish Mercury Database provides the most comprehensive summary of fish Hg measurements in Canada, and the results indicate that several regionally observed trends in fish Hg concentrations (e.g., Hgbiomagnification and geographic variation) are observed at a national scale. Implications for the effective assessment of changes in fish Hg concentrations in relation to changes in Hg emission regulations are discussed. Les concentrations de mercure (Hg) dans le poisson sont mesurees depuis 30 ou 40 ans dans toutes les regions du Canada, dans le cadre de divers programmes de surveillance et de recherche. Malgre cette vaste quantite de donnees, seules des evaluations regionales des tendances et distributions du Hg dans le poisson ont ete effectuees par le passe. L'objectif de l'etude consistait a regrouper les donnees disponibles sur les concentrations de Hg dans les poissons dulcicoles pour toutes les provinces et tous les territoires et a cerner les motifs de distribution a l'echelle nationale. La base de donnees canadienne sur le mercure dans le poisson (' Canadian Fish Mercury Database ') comprend plus de 330 000 entrees representant 104 especes de poisons dulcicoles echantillonnes dans plus de 5000 localites a la grandeur du pays, de 1967 a 2010. L'analyse des 28 especes les plus frequentes (>1000 entrees) a demontre que la situation geographique expliquait la majeure partie de la variabilite des concentrations de Hg (normalisees en fonction d'une taille standard). Les concentrations medianes de Hg augmentaient parallelement au niveau trophique (r = 0,40, p < 0,05), les poissons piscivores comme le dore (Sander vitreus), le grand brochet (Esox lucius)etle touladi (Salvelinus namaycush) presentant les plus fortes concentrations. La base de donnees canadienne sur le mercure dans le poisson constitue la synthese la plus exhaustive des mesures de Hg dans le poisson au Canada, et les resultats indiquent que plusieurs tendances observees a l'echelle regionale des concentrations de Hg dans le poisson (p. ex. bioamplification et variations geographiques du Hg) sont egalement observees a l'echelle nationale. Les consequences de ces resultats en ce qui concerne l'evaluation efficace de l'evolution des concentrations de Hg dans le poisson par rapport aux modifications de la reglementation en matiere d'emissions de Hg sont abordees. [Traduit par la Redaction], Introduction Anthropogenic activities have contributed to the increase in the global atmospheric mercury (Hg) pool during the 20th century (Pacyna et al. 2010). In Canada, with the exception of known [...]

A population of Laminaria longicruris de la Pylaie was followed for a year at Bic Island, Quebec, Canada where nutrient levels in the seawater were elevated throughout the year. Tagged kelp were measured each month for growth and analyzed for alginie acid laminaran, mannitol, carbon, nitrogen, and nitrate. Maximum growth (3.5 cm d[SUP-1]) was observed in June and minimal growth (0.18 cm d[SUP-1]) from December to February. when ice cover limited light levels. No reserves of carbon or nitrate were formed. Laminaran levels remained below 2.7% dry weight while tissue nitrate did not exceed 0.75 μmolg[SUP-1] dry weight. Total carbon produced per plant was 40 g Cyr[SUP-1]. Nutrient availabilily enables the kelp to take advantage of summer light and temperature canditions to grow rapidly. [ABSTRACT FROM AUTHOR]

Levels of Cr, Cu, Fe, Pb, Ni, and Zn in surface sediment from the Voisey's Bay area of coastal Labrador showed no evidence of recent anthropogenic input of metals. Metal concentrations in surface sediments,normalized to Li, fell within the 95% confidence limits of the background levels. Further analysis showed that the Li-metal regression lines from the surface sediments and sediments from 30-cm depth had thesame slope and intercepts, suggesting that there was no difference in the metal content of the sediments at the two depths. Li/metal relationships can be used as a measure of the natural variability of the metal concentrations for the region and will serve as a baseline against which future anthropogenic affects may be assessed. [ABSTRACT FROM AUTHOR]

In 1989, the tailings pond dam at the site of a former copper mine near Little Bay, Newfoundland and Labrador, Canada, ruptured and tailings spilled into Little Bay Arm. At the time, no action was taken to arrest the flow of tailings or to mitigate the effects of the spill. To date, no action has been taken to repair the dam and tailings continue to flow into Little Bay Arm. As a result, the marine environment around Little Bay Arm has become contaminated with heavy metals from the tailings. However, the tailings are not the only source of heavy metals to the ecosystem. An old slag heap and what is presumably concentrated copper ore spilled during the loading of ore freighters, are also contributing to the ecosystem's metal load. Marine sediment throughout the Arm contained elevated concentrations of Cu, Ni, Zn, As, V, Co, and Mn. Beach material also contained elevated concentrations of metals with material near the slag heap being the most contaminated. At this site, Cu concentrations were in excess of 5000 mg kg(-1) dry weight, Zn greater than 3000 mg kg(-1) and Co concentrations exceeded 700 mg kg(-1). The highest concentrations of metals in biota were found near the slag heap, near the tailings dam breach, and at the site of the former concentrate loading dock. Despite elevated metal concentrations, the tailings and nearby sediment were not devoid of life. Bivalves and seaweed were abundant in the area and there were no obvious signs of tissue damage or disease in soft shell clams (Mya arenaria) living in the tailings. These clams may be suffering from chronic exposure to the tailings, however, evidence of lipid peroxidation in the clams was inconclusive.