Erosion and Transport of Pollutants from the Terrestrial to the Aquatic Environment

The pathways followed by eroded and transported soil or mine spoil on its way to an aquatic environment involve an interrupted journey that is sometime completed in minutes or hours but which usually takes hundreds of years. The fate of most eroded sediment is to be periodically transported very short distances and to spend long periods at rest on hill slopes. The sites on slopes where transported soil accumulates, only temporarily retain soils and sediments (colluvium) so that should these be contaminated, they inevitably form a potential hazard. The main objective of this chapter is to explain the processes behind this risk. It aims to explain how long-term changes in some basic soil properties of accumulating and eroding soil affect rates of soil erosion, accumulation and transport of contaminants and nutrients in terrestrial environments.