title: Removal of toxic metals from leachates from hazardous solid wastes and reduction of toxicity to microtox by the use of calcium alginate beads containing humic acid.
abstract: Improper disposal of hazardous wastes can lead to release of potentially harmful substances through leaching such as heavy metals, which ultimately contaminate soil, sediment surface water, and groundwater through runoff. To remove these toxic metals and avoid any adverse effect on the ecosystem, a novel approach involving calcium alginate (CA) beads containing humic acid (HA) was used. For this, 10% leachates of the waste obtained from two major industrial units with electroplating processess were prepared at neutral pH and analyzed by atomic absorption spectrophotometry (AAS). Both leachates contained Cd, Cu, Cr, Ni, Mn, Fe, and Zn. The concentrations of Ni, Mn, Fe, and Zn in the waste were found to be significant. The leachates analyzed were passed through columns packed with calcium alginate beads with or without humic acid. The concentrations of various metals in beads and in different fractions collected after adsorption were measured. Data recorded indicate that calcium alginate beads containing humic acids are more efficient in removal of all metals in substantial amounts from the two leachates. Along with removal of metals, this process led to considerable detoxification of the leachates as tested by Microtox assay, indicated by earlier protection and higher EC(50). The significance of the results in relation to removal of toxic metals by beads containing humic acid is discussed.
authors.affiliation: Ecotoxicology Section, Industrial Toxicology Research Centre, M.G. Marg, Lucknow-226 001, India.
authors.forename: Ashok K
authors.initials: AK
authors.lastname: Pandey
authors.forename: Shri Dhar
authors.initials: SD
authors.lastname: Pandey
authors.forename: Virendra
authors.initials: V
authors.lastname: Misra
mesh_terms: D000327:Adsorption; D000464:Alginates / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D001673:Biodegradation, Environmental; D004787:Environmental Pollution / Q000517:prevention & control*; D020723:Glucuronic Acid; D006256:Hazardous Waste; D006603:Hexuronic Acids; D006812:Humic Substances / Q000737:chemistry*; D007928:Lethal Dose 50; D019216:Metals, Heavy / Q000032:analysis / Q000737:chemistry* / Q000633:toxicity*; D014733:Vibrio
chemical_list: D000464:Alginates; D001672:Biocompatible Materials; D006256:Hazardous Waste; D006603:Hexuronic Acids; D006812:Humic Substances; D019216:Metals, Heavy; D020723:Glucuronic Acid