Contaminants in Semi-aquatic Wildlife Lessons from the Laurentian Great Lakes

128 Semi-aquatic wildlife species have been important sentinels of environmental health and remain important biomonitors concerning emerging contaminant issues. The semi-aquatic wildlife of the Laurentian Great Lakes (LGL) has led the way in this regard and continues to do so. This is because the LGL and associated land mass possess a set of unique characteristics that make it an ideal laboratory for identifying the presence of environmental contaminants and their effects on semi-aquatic wildlife. The LGL basin and its diverse habitats support a wide array of wildlife with a significant number of species being dependent on the preponderance of coastline habitats. These species living in the transition areas of aquatic and terrestrial environments are exposed to contaminants from broad sources. As a result, semi-aquatic wildlife species often experience exposure to contaminants that are greater than for either terrestrialor aquatic-based species and thus have been key sentinels of environmental health, both in the LGL basin and elsewhere. For the LGL, human activities including industrial, agricultural and recreational have resulted in significant inputs of anthropogenic contaminants. The combination of contaminant input and shoreline habitats with slow water turnover rate results in a great potential for chronic contaminant exposure of semi-aquatic wildlife species. In 1962, environmental awareness was brought to the forefront when the observations of a LGL scientist were published in Rachel Carlson’s Silent Spring. The assumptions that environmental contaminants were not very toxic and that the dilution potential of the LGL was infinite were clearly in error. Over the next 30 years, declines in individual and population health of LGL semi-aquatic species including mink, otter, bald eagles, terns, cormorants and numerous amphibian species warned the world of the potential for widespread, adverse impacts of contaminants on the environment. Compounds such as DDT, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and a great number of pesticides were being identified in the tissues of these species at concentrations associated with adverse effects. Today, through the combined work of scientists, government and industry, exposure to identified contaminants has been reduced within the LGL. As a result, populations of mink, eagles and cormorants and other semi-aquatic wildlife species have seen increases over the last two decades and the lessons learned have pushed this trend worldwide. Today more than 600 programmes are utilised to monitor the environmental health Contaminants in Semi-aquatic Wildlife Lessons from the Laurentian Great Lakes