title: X-ray absorption and micro X-ray fluorescence spectroscopy investigation of copper and zinc speciation in biosolids.
abstract: Despite its pivotal role in determining the risks and time frames associated with contaminant release, metal speciation remains a poorly understood aspect of biosolids chemistry. The work reported here used synchrotron-based spectroscopy techniques to investigate the speciation of copper and zinc in a range of Australian biosolids. High resolution element mapping of biosolids samples using micro X-ray fluorescence spectroscopy revealed considerable heterogeneity in key element associations, and a combination of both organic and inorganic copper and zinc binding environments. Linear combination fitting of K-edge X-ray absorption spectra indicated consistent differences in metal speciation between freshly produced and stockpiled biosolids. While sulfide minerals play a dominant role in metal binding in freshly dewatered biosolids, they are of lesser importance in dried biosolids that have been stockpiled. A degree of metal binding with iron oxide minerals was apparent but the results did not support the hypothesis that biosolids metals are chiefly associated with iron minerals. This work has potential implications for the long-term stability of metals in biosolids and their eventual fate following land application.
authors.affiliation: Centre for Environmental Risk Assessment and Remediation, University of South Australia, Building X, Mawson Lakes Campus, South Australia 5095, Australia. erica.donner@unisa.edu.au
authors.forename: Erica
authors.initials: E
authors.lastname: Donner
authors.forename: Daryl L
authors.initials: DL
authors.lastname: Howard
authors.forename: Martin D
authors.initials: MD
authors.lastname: de Jonge
authors.forename: David
authors.initials: D
authors.lastname: Paterson
authors.forename: Mun Hon
authors.initials: MH
authors.lastname: Cheah
authors.forename: Ravi
authors.initials: R
authors.lastname: Naidu
authors.forename: Enzo
authors.initials: E
authors.lastname: Lombi
mesh_terms: D001315:Australia; D003300:Copper / Q000032:analysis*; D012722:Sewage / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*; D013052:Spectrometry, X-Ray Emission / Q000379:methods*; D056928:X-Ray Absorption Spectroscopy / Q000379:methods*; D015032:Zinc / Q000032:analysis*
chemical_list: D012722:Sewage; D012989:Soil Pollutants; D003300:Copper; D015032:Zinc