heavy metals

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 of this toxic element, a sign that human activities may be adding to an existing burden of mercury in Arctic animals and the people who eat those animals? With cadmium, what role does natural geology play in relation to anthropogenic inputs in explaining levels in animals that are high enough to raise health concerns? In spite of such uncertainties, one message is clear: these metals matter because they accumulate in the bodies of Arctic animals and hence become available to humans who depend on wildlife for their survival.

This chapter discusses the sources of heavy metals in the Arctic environment and describes their levels in air, sediment, water, and biota. Based on current understanding of the behavior of metals in the environment and their toxicology, the chapter attempts to assess the impact of some metals on plants and animals. The focus is both on large-scale contamination and on the severe local ecological effects found near some industrial sites in the Arctic. The potential impacts of metals on human health are covered in the chapter Pollution and Human Health.

Heavy metals - an introduction

Metals occur naturally in the environment and are present in rocks, soil, plants, and animals. Metals occur in different forms: as ions dissolved in water, as vapors, or as salts or minerals in rock, sand, and soil. They can also be bound...