title: Heavy metal bioavailability in a soil affected by mineral sulphides contamination following the mine spillage at Aznalcóllar (Spain).
abstract: A field experiment, lasting 14 months, was carried out in order to assess the effect of organic amendment and lime addition on the bioavailability of heavy metals in contaminated soils. The experiment took place in a soil affected by acid, highly toxic pyritic waste from the Aznalcóllar mine (Seville, Spain) in April 1998. The following treatments were applied (3 plots per treatment): cow manure, a mature compost, lime (to plots having pH < 4), and control without amendment. During the study two crops of Brassica juncea were grown, with two additions of each organic amendment. Throughout the study, the evolution of soil pH, total and available (DTPA-extractable) heavy metals content (Zn, Cu, Mn, Fe, Pb and Cd), electrical conductivity (EC), soluble sulphates and plant growth and heavy metal uptake were followed. The study indicates that: (1) soil acidification, due to the oxidation of metallic sulphides in the soil, increased heavy metal bioavailability; (2) liming succeeded in controlling the soil acidification; and (3) the organic materials generally promoted fixation of heavy metals in non-available soil fractions, with Cu bioavailability being particularly affected by the organic treatments.
authors.affiliation: Department of Soil and Water Conservation and Organic Waste Management, Centro de Edafología y Biología Aplicada del Segura, CSIC. Apartado 4195, 30080 Murcia, Spain. rclemente@cebas.csic.es
authors.forename: Rafael
authors.initials: R
authors.lastname: Clemente
authors.forename: David J
authors.initials: DJ
authors.lastname: Walker
authors.forename: Asunción
authors.initials: A
authors.lastname: Roig
authors.forename: M Pilar
authors.initials: MP
authors.lastname: Bernal
mesh_terms: D001682:Biological Availability; D004787:Environmental Pollution / Q000517:prevention & control; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste / Q000517:prevention & control; D008372:Manure; D019216:Metals, Heavy / Q000378:metabolism* / Q000493:pharmacokinetics; D008906:Mining; D009149:Mustard Plant / Q000254:growth & development; D063245:Plant Development; D012987:Soil; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism* / Q000493:pharmacokinetics; D013030:Spain; D013440:Sulfides / Q000378:metabolism*
chemical_list: D007220:Industrial Waste; D008372:Manure; D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants; D013440:Sulfides