Colonial Waterbird Health and Contaminants
This data set contains concentrations of heavy metals, including mercury, polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) and stable nitrogen isotopes in five species of colonial waterbird eggs (California Gull, Herring Gull, Ring-billed Gull, Common Tern and Caspian Tern) collected from two sites near the Peace-Athabasca Delta (Egg Island and Mamawi Lake) and from one site in southern Alberta (Langdon Reservoir). Data are available for 1977, 2009, 2011, 2012 and 2013 for the northern Alberta sites and from 2008 to 2013 for the southern Alberta site.
While no applicable guidelines exist for these measurements, our expert assessment is that the observed concentrations are not likely to pose a risk to these bird populations.
Data from the period 2008 to 2013 show that while mercury concentrations in eggs vary from one year to the next, there is no evidence that egg mercury concentrations have increased over that time period. Mercury concentrations in California Gull eggs from Egg Island collected from 2008 to 2013 are higher than in California Gull eggs collected from the same location in 1977.
Data for other heavy metals, PCDDs and PCDFs do not reveal any patterns over space or time.