In addition, human activities have also resulted in increased emissions of metals. Heavy metals include those whose atomic weight is greater than approximately 50. Some metals also bioaccumulate in organisms, which can adversely affect the organism as well as people who consume it. In the Arctic, there are both local and long-range sources of natural and anthropogenic metal contamination. Deposition of Arctic haze from the atmosphere contributes pollutants from distant sources.
Larger particles tend to deposit mostly as dry deposition.
In regions with acidified rainfall or ambient conditions, naturally occurring metals may be leached from the soil and enter the terrestrial and aquatic ecosystems. As a result, muddy sediments tend to have higher contaminant levels than sandy sediments.