Mercury in the Great Lakes region: bioaccumulation, spatiotemporal patterns, ecological risks, and policy

Abstract

This special issue examines bioaccumulation and risks of methylmercury in food webs, fish and wildlife in the Laurentian Great Lakes region of North America, and explores mercury policy in the region and elsewhere in the United States and Canada. A total of 35 papers emanated from a bi-national synthesis of multi-media data from monitoring programs and research investigations on mercury in aquatic and terrestrial biota, a 3-year effort involving more than 170 scientists and decision-makers from 55 different universities, non-governmental organizations, and governmental agencies. Over 290,000 fish mercury data points were compiled from monitoring programs and research investigations. The findings from this scientific synthesis indicate that (1) mercury remains a pollutant of major concern in the Great Lakes region, (2) that the scope and intensity of the problem is greater than previously recognized and (3) that after decades of declining mercury levels in fish and wildlife concentrations are now increasing in some species and areas. While the reasons behind these shifting trends require further study, they also underscore the need to identify information gaps and expand monitoring efforts to better track progress. This will be particularly important as new pollution prevention measures are implemented, as global sources increase, and as the region faces changing environmental conditions.

Mercury in Nelson's Sparrow Subspecies at Breeding Sites

“…In some bird species, mercury concentrations of 2.4–40.0 ppm in feathers and 0.7–3.0 ppm in blood have been related to impaired reproduction [3], [4], [6]. Because mercury toxicity and physiology have species-specific components [3], [7], [8], and recent research indicates that we may have underestimated the effect of environmental mercury on wildlife [9], it is increasingly necessary to characterize the potential threat that mercury poses in various ecosystems. Marsh habitats are often areas of high mercury methylation and subsequent bioaccumulation because of their hydrology, acid-base status and sediment characteristics [10], [11].…”

Linking fecal bacteria in rivers to landscape, geochemical, and hydrologic factors and sources at the basin scale

“…Deforestation (3) and increased impervious surface area (4) have been linked with decreased infiltration and thus increased surface runoff. Overland flows concentrate pollutants and rapidly transport them down gradient where they eventually enter surface water systems and affect water quality (5,6). A number of models have been developed to calculate overland and surface water flows (7,8) and nutrient/chemical transport (9), but few studies have focused on microbial movement from land to water, particularly nontraditional fecal indicator bacteria that can be used to track human sources of pollution.…”

Meteorological Modeling Using the WRF-ARW Model for Grand Bay Intensive Studies of Atmospheric Mercury

“…It is therefore important to understand the sources of atmospheric mercury emissions, as well as its atmospheric fate and transport. The Great Lakes region has been one focus of study [2][3][4], while mercury pollution in the Gulf of Mexico region has also drawn increasing attention in recent years [5]. The observed atmospheric wet deposition flux of mercury in the Gulf of Mexico region is higher than that in any other region in the United States [6][7][8].…”