title: Evaluation of interactions between soil and coal fly ash leachates using column percolation tests.
abstract: The aim of this work was the assessment of the environmental impact of different origin fly ashes with regard to their final disposal. The experimental procedure included the performance of single column tests and column tests of fly ash and soil in series. The appraisal of the potential environmental hazards was implemented using physicochemical analyses and bioassays. Two different fly ash samples were examined, one fly ash produced from the combustion of sub-bituminous coal (CFA) and one fly ash produced from the combustion of lignite (LFA). Single column percolation tests were performed according to NEN 7343 protocol, while fly ash/soil experiments were conducted incorporating slight modifications to this protocol. The study focused on the release of metals Ba, Cr, Cu, Mo, Se and Zn and the ecotoxic behavior of leachates on crustacean Daphnia magna and bacteria Vibrio fischeri. The infiltration of the leachates of both fly ashes through soil affected considerably their leaching profile. The transport of Cu and Zn was facilitated by the dynamic leaching conditions and influenced by the pH of the leachates. Moreover, the release and bioavailability of Cr, Cu and Zn was probably altered during the infiltration experiments and organisms' response was not always correlated with the concentration of metals. Nevertheless, the results are signalling that possible manipulations and final disposal of fly ash should be considered when environmental threats are investigated.
authors.affiliation: Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece. Electronic address: tsiridis@civil.auth.gr.
authors.forename: V
authors.initials: V
authors.lastname: Tsiridis
authors.affiliation: Division of Hydraulics and Environmental Engineering, Department of Civil Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
authors.forename: M
authors.initials: M
authors.lastname: Petala
authors.affiliation: Department of Food Technology, Technological Educational Institute of Thessaloniki, 57400 Thessaloniki, Greece.
authors.forename: P
authors.initials: P
authors.lastname: Samaras
authors.affiliation: Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
authors.forename: G P
authors.initials: GP
authors.lastname: Sakellaropoulos
mesh_terms: D048908:Aliivibrio fischeri / Q000187:drug effects; D000818:Animals; D060729:Coal Ash / Q000032:analysis / Q000737:chemistry* / Q000633:toxicity*; D003621:Daphnia / Q000187:drug effects; D054750:Ecotoxicology / Q000379:methods*; D004777:Environment; D008670:Metals / Q000032:analysis; D012987:Soil / Q000737:chemistry*; D018675:Toxicity Tests / Q000379:methods
chemical_list: D060729:Coal Ash; D008670:Metals; D012987:Soil
keywords: Column percolation test; Ecotoxicity; Fly ash; Heavy metals; Soil