Erosion and leaching

Erosion and Leaching Losses Following Deforestation and Biomass Burning. 

Figure 7. Another temperate coniferous forest site of the Pacific Northwest, USA following clearcutting and slash burning. Severe levels of deforestation result in large quantities of nutrient losses through wood export, biomass burning and accelerated erosion and leaching losses. (Photograph is by courtesy of Dian L. Cummings. ...

Approximately 44 000 t of arsenic are annually removed from soils (Matschullat, 2000), 303. Major processes that eliminate arsenic from soils include microbial volatilization (up to 26,200 tyear-1 (Matschullat, 2000), 300-301), plant uptake, wind and water erosion, and leaching into precipitation, irrigation water, and groundwater (Matschullat, 2000 Bar-Yosef, Chang and Page, 2005). 

Natural sources of vanadium release to water include wet and dry deposition, soil erosion, and leaching from rocks and soils. The largest amount of vanadium release occurs naturally through water erosion of land surfaces. It has been estimated that approximately 32,300 tons of vanadium are dissolved and transported to the oceans by water, and an additional 308,650 tons are thought to be transported in the form of particulate and suspended sediment (Van Zinderen Bakker and Jaworski 1980). 

According to Pierrou, about 13 Mt P reach the soils of the world annually by each of these pathways, while a similar amount (ca. 12 Mt) is lost through soil erosion and leaching. Plants have been estimated to remove somewhere between 178 and 240 Mt P, while biological returns amount to about 100 Mt annually. An even faster water-based P cycle, with turnover times measured in months rather than years as for the land-based cycle, is essentially closed, with the very small quantity of P entering the oceans in rivers being approximately balanced by that removed in sediments. ... 

For the various AB cements used in clinical dentistry, erosion and/or leaching of components have been considered important in assessing durability (Wilson McLean, 1988). In fact, the two aspects are not... 

Surface erosion particle diffusion and leaching Total disintegration of particles Environment... 

Mlrex. Mirex does not leach into the soil profile and is predicted to volatilize only slowly. There Is no evidence for any rapid transformation so it should be considered persistent. Because It is so strongly adsorbed to the soil and stays on the surface, a major loss from terrestrial systems would probably be erosion and transport Into surface waters. 

Erosion, nutrient leaching and pollution emission Landscape homogenisation... 

Although these reservoirs may be highly contaminated with PCDD/PCDFs, the chemical and physical properties of these compounds imply that dioxins and furans will stay adsorbed to organic carbon in soils or other particles. On the other hand, mobilization can occur in the presence of lipophilic solvents (leaching into deeper layers of soils and/or groundwater) or in cases of erosion or run-off from topsoil (translocation into the neighbourhood). Experience has shown that transport of PCDD/PCDFs due to soil erosion and run-off does not play a major role in environmental contamination and human exposure (Fiedler 1995, 1999). 

The history of erosion and redeposition in the Amazon basin has led to an extensive leaching of nutrients, particularly the common... 

Like nitrates, phosphates are included in the indicative list of main pollutants (Water Framework Directive, 2000/60/EC) because of their contribution to eutrophication. Phosphorus is an essential nutrient for all plants and in modem agriculture this element has to be supplied to the crops as fertilizer. Wind erosion, surface mnoff and leaching constitute the main pathways for transport of phosphoms from terrestrial to aquatic ecosystems. The process is accelerated by agriculture, animal husbandry and anthropogenic discharges. 

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