Contaminated Sediments: Inorganic Constituents
Part 7. Erosion and Sedimentation
Published Online: 15 SEP 2008
Copyright © 2005 John Wiley & Sons, Ltd. All rights reserved.
Encyclopedia of Hydrological Sciences
How to Cite
Horowitz, A. J. 2008. Contaminated Sediments: Inorganic Constituents. Encyclopedia of Hydrological Sciences. 7.
- Published Online: 15 SEP 2008
Owing to a variety of physical and chemical factors, in conjunction with aquatic physicochemical conditions, fluvial/lacustrine suspended and bed sediments can act as both sources and carriers of a wide variety of inorganic constituents and nutrients. Many of these constituents reflect local environmental conditions and are derived from both point and nonpoint sources. When sources have an anthropogenic origin, and chemical levels exceed the typical range of local baseline concentrations, sediments can be described as contaminated. Most land-use categories (e.g. agriculture, forested, and rangeland) do not appear to exert a substantial effect on sediment-associated inorganic chemical levels. On the other hand, mining and/or mining-related activities are a major exception, and although this land use can be geographically limited, it can cause extensive local and downstream sediment contamination. Urban centers and urbanization (increasing amounts of impervious surfaces), as a result of industrial and wastewater discharges, power generation, and transportation-related activities, also can cause extensive sediment contamination. Population density can be related to urbanization and, at levels ≥27 people (p) km−2, also appears to exercise a substantive effect on sediment chemistry. In fact, population density appears to be a more consistent influence than urban percentage, and displays stronger positive correlations with sediment contamination. The most common sediment-associated inorganic/nutrient contaminants appear to be Pb, Hg, Ag, Zn, Cd, Cu, Sb, S, Ni, Sn, Cr, As, TC (total carbon), Co, Fe, P, and TOC (total organic carbon).
- trace elements;
- urban effects;
- mining effects