This leaves a yellow rust stain on stream boulders and can kill aquatic life. This is very common and is a major environmental problem here in Colorado. Clear Creek just below the town of Blackhawk. Not only does the acid kill aquatic life, but all of the heavy, toxic, chalcophile metals like lead, zinc, cadmium, and mercury are mobilized in the process. Erosion is the reduction of exposed landforms.
Transportation is the movement of eroded material downslope.
A soil is an accumulation of weathered rock material together with organic matter at the Earth's surface. Soils are classified into pedalfers and pedocals. Extreme pedocals may contain salt and borate deposits. Pedalfers are soils of humid regions and are characterized by highly leached clays due to downward movement of water. Here is a laterite soil cross section in Brazil.