Global Threats of Indigenous Contaminants to Soil and Water Quality.

Anthropogenic contamination of soils often leads to acute but spatially constrained threats to surface and groundwater quality. By contract, naturally occurring contaminants generally lead to lower dissolved concentrations but cover vast geographic areas, which can cover expanses that reach thousands of square kilometers. Here, the range of major indigenous contaminant and the processes leading to degraded water quality are explored. Examples of present and past threats are described, and future threats arising from increasing stresses on our water resources coupled with global and climate change are explored.