Évolution temporelle des concentrations de mercure dans les plumes d’oiseaux de proie au Québec

Des analyses de mercure ont été effectuées sur des plumes de 7 espèces d’oiseaux de proie récoltées au Québec entre les années 1906 à 2002. Une diminution temporelle des concentrations a été observée chez les aigles royaux et les autours des palombes. Chez les jeunes balbuzards pêcheurs élevés à proximité des réservoirs hydroélectriques, une diminution des concentrations de mercure d’environ 33 % est observée entre 1989-1991 et 1997. Cette diminution serait liée à la baisse des concentrations de mercure chez les poissons vivant dans les réservoirs. Les espèces se nourrissant dans les milieux aquatiques, le pygargue à tête blanche et le balbuzard pêcheur, présentent des concentrations de mercure de 2 à 30 fois plus élevées que celles qui s’alimentent en milieux terrestres. Chez le pygargue à tête blanche, les concentrations apparaissent élevées et augmentent avec l’âge des oiseaux échantillonnés.Feathers collected from 7 raptor species in Québec between 1906 and 2002 were screened for mercury. The concentrations found in golden eagle and northern goshawk feathers decreased over time. In addition, over the 6- to 8-year period between 1989-1991 and 1997, a 33% decrease in mercury levels was observed in feathers collected from osprey chicks reared in nests close to hydroelectric reservoirs. This decrease is likely linked to a reduction in the mercury levels in the tissues of fish within the reservoirs. In general, however, feathers from bald eagles and ospreys, which feed in aquatic environments, showed mercury levels from 2 to 30 times higher than those from species foraging in terrestrial environments. In the case of the bald eagle, mercury levels were high and the concentration increased with the age of the birds

The R1 subunit of herpes simplex virus ribonucleotide reductase is a good substrate for host cell protein kinases but is not itself a protein kinase

UI - 98104124NRC publication: Ye

Mercury trends in herring gull (Larus argentatus) eggs from Atlantic Canada, 1972-2008: Temporal change or dietary shift?

Mercury (Hg) is a pervasive contaminant that can adversely affect predatory wildlife. Bird eggs provide insights into breeding females' Hg burdens, and are easily collected and archived. We present data on Hg trends in herring gull (Larus argentatus) eggs from five sites in Atlantic Canada from 1972 to 2008. We found a significant decrease in Hg at Manawagonish Island, New Brunswick and Île du Corossol, Quebec, but after correcting Hg for dietary shifts using stable isotopes (δ15N), these trends disappeared. Decreasing temporal trends of stable isotopes in gull eggs were observed at four sites, suggesting shifts in gull diets. At Gull Island, Newfoundland, diet-adjusted Hg increased from 1977 to 1992, dropped sharply between 1992 and 1996, and rose again from 1996 to 2008. After adjusting Hg trends for dietary shifts of herring gulls, it appears that environmental Hg in coastal ecosystems has remained relatively constant at most sites in Atlantic Canada over the last 36 years

Contamination and Biomarkers in the Great Blue Heron, an Indicator

breeding colonies of the great blue heron on the St. Lawrence River and its 12 estuary (Que´bec, Canada) were investigated in the framework of a biomonitoring program. Fledglings from 13 colonies in freshwater were more contaminated with mercury, PCBs and many organic contaminants than 14 those from estuarine colonies. The level of contamination in the St. Lawrence River is generally below the 15 levels of toxicological effects for the great blue heron. The molar ratio of retinol: retinyl palmitate in heron 16 eggs was correlated with total PCBs (r=0.79) and mirex (r=0.90). In plasma, all biochemical parameters 17 were significantly different between freshwater and marine colonies. Plasma retinol concentrations at the 18 Dickerson and He´ron colonies were significantly lower compared with those at Grande Ile (p<0.05) and 19 Steamboat (p<0.001). Based on retinoid and b-carotene concentrations in eggs, low plasma retinol was not 20 associated with possible dietary deficiency. Plasma retinol was negatively correlated with many PCB 21 congeners, total PCBs (r=)0.78), p,p¢-DDE, trans-nonachlor and a-HCH. Similarly, the hormone T3 was 22 correlated with many PCB congeners, total PCBs (r=)0.69) and the same organochlorine chemicals. 23 Plasma LDH concentrations were different among freshwater colonies, Grande Ile and He´ron colonies 24 having LDH values significantly greater than those of Steamboat (respectively, p<0.05 and p<0.01). 25 Globally, the health status of the St. Lawrence great blue heron population was judged to be acceptable, 26 however, several biomarkers indicated positive responses to contaminants

Feather corticosterone during non-breeding correlates with multiple measures of physiology during subsequent breeding in a migratory seabird.

International audienceCarry-over effects in migratory birds are likely mediated by physiological processes that are activated in response to environmental variation. Such processes affect body condition and/or reproductive success, and can include corticosterone (CORT) because this hormone responds to environmental stressors and influences energy balance. Few studies have considered how CORT levels during non-breeding relate to a broader physiological profile during subsequent breeding, and fewer still have considered measures other than body condition. To explore CORT's potential role in carry-over effects, we investigated the relationship between CORT and foraging ecology of northern gannets (Morus bassanus) during the non-breeding period, and tested for associations between these factors and variation in a suite of physiological and biochemical metrics during subsequent breeding. Northern gannets are the largest seabird top predator in the North Atlantic and were among the hardest hit by the Deepwater Horizon oil blowout in the Gulf of Mexico in 2010. We used light-level geolocators to confirm winter origins of individuals in our study. No interrelationships were found among levels of CORT from feathers grown during non-breeding (CORTf) and variation in foraging ecology, measured by stable isotopes of carbon (δ(13)C) and nitrogen (δ(15)N) from the same feathers. CORTf was correlated negatively with hematocrit and positively with triglyceride measured during subsequent incubation, and explained more variation in these variables than did body mass during incubation. These findings provide support for the hypothesis that energy management, measured using CORTf, during non-breeding carries over to influence physiological measures other than body condition. Gannets that previously wintered within the Gulf of Mexico in the years following the Deepwater Horizon oil blowout had higher levels of CORTf compared to birds that wintered along the Atlantic coast, suggesting an increased energetic cost associated with visiting the Gulf of Mexico. Our results indicate that CORT during non-breeding is associated with a broader physiological profile during subsequent breeding than previously reported in birds

Perfluoroalkyl Acids in European Starling Eggs Indicate Landfill and Urban Influences in Canadian Terrestrial Environments

Perfluoroalkyl acids (PFAAs) were determined in European starling (<i>Sturnus vulgaris</i>) eggs collected between 2009 and 2014 from industrial, rural/agricultural, and landfill locations within five urban centers across Canada. Within each urban center, perfluoroalkyl sulfonic acid (PFSA) concentrations were generally greater in starling eggs collected from urban/industrial locations and PFSAs and perfluoroalkyl carboxylic acids (PFCAs) were generally greater at landfills compared to rural and remote locations. However, the relative importance of urban/industrial versus landfill locations as potential sources was chemical- and location-specific. PFSA concentrations in eggs collected from nonlandfills were positively correlated with human population. Despite the 2000 to 2002 phase-out of perfluorooctanesulfonic acid (PFOS) and its C₈ precursors, leaching from consumer products during use likely continues to be a major source to the environment. In comparison, the concentrations of most PFCAs in eggs were not related to population, which supports the hypothesis that atmospheric transport and degradation of precursor chemicals are influencing their spatial trends. PFAA concentrations in eggs from landfills were not correlated with the quantity of waste received by a given landfill. The variability in PFAAs between landfills may be due to the specific composition of waste items