Tuesday, 8 November 2005
9

Physical and chemical characterization of two mining soils – Risk reduction by phytostabilization.

Andrea Zanuzzi and Angel Faz. Universidad Politécnica de Cartagena, Paseo de Alfonso XIII, 48, Cartagena, 30203, Spain

Mining soils greatly polluted with heavy metals are a result of the intense mining activity carried out in Cartagena-La Unión Mountain, in the Murcia region Southeast Spain, since roman times. Such materials are often a major source of heavy metal pollution for the local environment owing to dust blow and to the leaching of the mineral weathering products into nearby watercourses. Two representative silt ponds of the area were physical and chemically characterizated in order to assess the associated risks, and to plan a remediation programme. Between the available reclamation techniques, revegetation gives a cost-effective and environmentally sustainable method of stabilising mining soils. Phytostabilisation makes use of contaminant-tolerant species, while the establishment of vegetation on polluted soils helps prevent erosion and metal leaching. However, many characteristics of these soils are inimical for successful vegetation establishment, such as acidity, phytotoxic levels of residual heavy metals (Cd, Pb, Zn and Cu), low nutrient status, and poor physical structure of the substratum. Therefore only neutralization could prevent acid drainage and remobilization of metallic ions. Adding carbonate and organic materials to acidic soil is the primary way to remediate exposed mine lands which: produce acid mine drainage, erode easily and/or cannot support vegetation due to low soil pH, depleted nutrient and organic matter content, and/or the presence of toxic metals. For that reason, in order to reduce risks associated to heavy metal pollution, phytostabilization combined with carbonate and organic amendments could be a suitable technique for the mining area of Cartagena-La Unión.


Handout (.pdf format, 132.0 kb)

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