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DEGRADATION AND CONTROL PROCESSES |
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Degradation process:
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Due to the release of toxic products.
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Description:
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Application of pollutants from industrial, urban or rural activities to the soil. Contaminated soils are mainly associated with old industrial areas, and also with inadequate recycling of sewage sludge or inadequate (industrial or agricultural) waste management.
Importance: localized.
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Soil functions affected:
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This may contaminate the soil (locally or diffusely), affect the food chain, and threaten water quality and human health. In some countries, the application of ore concentration techniques to the sludge is being studied as a way of in order to retrieve environmentally toxic metals and thus reduce their toxicity.
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Click on the image
Soil contaminated by sludge from the decantation pool containing spoils from sulphide mining, as a result of the accidental breaking of one of the pool’s
walls of contention. Leaf necrosis can be observedAznalcóllar (Sevilla) (M. López-Acevedo)
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Diagnostic criteria:
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The European Union has established a Contaminated Soils Directive which has, in turn, given rise to associated legislation in the different member states. This envisages specific protocols for inventories of contaminated soils. In the case of Spain, RD 9/2005 establishes the relationship between potentially soil-contaminating activities and for criteria and standards relating to the declaration of contaminated soils.
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Prevention and control:
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It is both difficult and costly to recover contaminated soils. It is therefore necessary to foresee the potential need for decontamination processes before assigning new functions to old industrial areas, especially when the objective is to recover them with a new function such as a leisure area (children’s playgrounds for example).
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Click on the image
The contamination of soils makes soil decontamination
processes necessary and these are very
expensive. This was seen in the thickness of the soil layer that had to be mechanically removed
following the Aznalcollar disaster (Seville, Spain)
(M. López-Acevedo)
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