Anthropogenic sources of metals can have severe and obvious impacts on the local environment, but signs of environmental change across a larger region and on a broader scale are subtle and difficult to interpret. Connecting dead trees and bare ground to a nearby smelter complex is not hard. But what does it mean when mercury levels are higher in the upper part of ocean and lake sediments. Could it be evidence of an increased circulation …showed first 75 words of 9530 total…

…showed last 75 words of 9530 total… the Yukon Territory in Canada, which is known to have cadmium-rich geology. Cadmium levels seem to be highest in marine animals from northeastern Canada and Northwest Greenland. For certain age groups and populations of marine birds and mammals, the levels might be high enough to cause kidney damage. Lead generally does not pose a threat to Arctic ecosystems because it does not bioaccumulate. Moreover, lead levels have been decreasing for the past two decades.