Mercury Trends in Colonial Waterbird Eggs Downstream of the Oil Sands Region of Alberta, Canada

• DOI: 10.1021/es402542w
• Publication Date: 2013-09-26T16:34:54Z
• Authors: Craig E. Hebert; David Campbell; Rhona Kindopp; Stuart MacMillan; Pamela Martin; Ewa Neugebauer; Lucy Patterson; Jeff Shatford
• Keywords: Mercury; Tern

Mercury levels were measured in colonial waterbird eggs collected from two sites northern Alberta and one site southern Alberta, Canada. Northern the Peace-Athabasca Delta Lake Athabasca located receiving waters of River which drains oil sands industrial region north Fort McMurray, Alberta. Temporal trends egg mercury (Hg) assessed as stable nitrogen isotope values an indicator dietary change. In California Ring-billed Gulls exhibited statistically significant increases Hg concentrations 2012 compared to data earliest year sampling. Caspian Common Tern showed a nonstatistically increase. Gull declined significantly through time. Bird change was not responsible for any these trends. Neither related recent forest fires. Differences temporal between combined with greater identified likely importance local sources regulating regional gull generally below generic thresholds associated toxic effects birds. However, 2012, majority exceeded lower toxicity threshold. Increasing multiple species nesting downstream warrant continued monitoring research further evaluate conclusively identify sources.