title: Extractability and leachability of heavy metals in Technosols prepared from mixtures of unconsolidated wastes.
abstract: Mixtures of wastes were prepared to improve on the characteristics of the individual ingredients as Technosols, with special attention given to heavy metal extractability. An anaerobic digested sewage sludge and a CaO-treated aerobic sludge were used. A mixture of the two sludges (50:50 DW basis) was also prepared to provide a third type of sludge. The residues were mixed with other types of waste, such as fly ash, Linz-Donowitz slag, foundry sand, shot blasting machine scrap, fettling and barley straw. Extractability of Cu, Cr, Ni, and Zn by 0.01 M CaCl(2) extraction (Me(CACI(2)) was carried out, and leachability of these elements was estimated by acidification of an aqueous suspension of the mixtures with 0.5 N acetic acid (Me(acetic)). The total concentrations of the metals were also determined (Me(T)). The Me(CACI(2)/Me(T) ratios for Cu and Ni (means: 4.0% and 3.1%) were higher than those for Cr and Zn (means: 0.07% each). The mean Me(acetic)/Me(T) ratios followed the order Ni, Zn, Cu, and Cr (19.5%, 4.1%, 3.7%, and 0.09%, respectively). The results highlight the existence of complex interactions among organic matter solubility, pH and heavy metal extractability.
authors.affiliation: NEIKER, Agroecosistemas y Recursos Naturales, Berreaga 1, 48160 Derio, Bizkaia, Spain. mcamps@neiker.net
authors.forename: M
authors.initials: M
authors.lastname: Camps Arbestain
authors.forename: Z
authors.initials: Z
authors.lastname: Madinabeitia
authors.forename: M
authors.initials: M
authors.lastname: Anza Hortalà
authors.forename: F
authors.initials: F
authors.lastname: Macías-García
authors.forename: S
authors.initials: S
authors.lastname: Virgel
authors.forename: F
authors.initials: F
authors.lastname: Macías
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D002122:Calcium Chloride / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D019216:Metals, Heavy / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry*; D012995:Solubility; D013997:Time Factors
chemical_list: D019216:Metals, Heavy; D012722:Sewage; D002122:Calcium Chloride