title: Arsenic and lead leaching from the waste derived fertilizer ironite.
abstract: The toxicity characteristic leaching procedure (TCLP) and the synthetic precipitation leaching procedure (SPLP) were performed on commercially purchased samples of the waste-derived soil amendment marketed as Ironite. Ten samples of the 1-0-0 grade (the most widely available in Florida) were tested. Two samples of the 12-10-10 grade and three samples of the 6-2-1 grade (a liquid version) were tested as well. TCLP leachate concentrations from the 1-0-0 grade samples ranged from 5.0 to 8.0 mg L(-1) for lead and 2.2 to 4.8 mg L(-1) for arsenic. SPLP concentrations from the 1-0-0 samples ranged from 0.62 to 3.1 mg L(-1) for lead and 1.9 to 8.2 mg L(-1) for arsenic. All of the 1-0-0 grade samples exceeded the U.S. hazardous waste toxicity characteristic (TC) limit for lead (5 mg L(-1)), while five of the 10 SPLP samples exceeded the TC limit for arsenic (5 mg L(-1)). The greater arsenic leachability in the SPLP relative to the TCLP was determined to be a result of lower pH conditions in the SPLP. A composite sample of the 1-0-0 grade was found to leach much greater concentrations of both arsenic and lead using California's waste extraction test (WET). Lead leachate concentrations were much lower in the two 12-10-10 samples (0.03 mg L(-1) or less); arsenic concentrations in these leachates (both TCLP and SPLP) exceeded 5 mg L(-1). None of the 6-2-1 samples contained lead or arsenic above TC limits. An experiment performed on the 1-0-0 grade which examined leachability as a function of pH found that at pH values in the range of what is encountered in the human digestive system (pH 4.0 to 1.5) lead leached 2-36% of its initial content, and arsenic leached 1-6% of its initial content. A simple gastric acid leaching experiment found 83 and 37% of the lead and arsenic present to leach, respectively.
authors.affiliation: Department of Environmental Engineering Sciences, University of Florida, Gainesville, Florida 32611-6450, USA.
authors.forename: Brajesh
authors.initials: B
authors.lastname: Dubey
authors.forename: Timothy
authors.initials: T
authors.lastname: Townsend
mesh_terms: D001130:Arizona; D001151:Arsenic / Q000032:analysis* / Q000737:chemistry; D005308:Fertilizers / Q000032:analysis*; D006256:Hazardous Waste / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000032:analysis* / Q000737:chemistry; D008906:Mining; D012989:Soil Pollutants / Q000032:analysis*; D012995:Solubility
chemical_list: D005308:Fertilizers; D006256:Hazardous Waste; D012989:Soil Pollutants; D007854:Lead; D001151:Arsenic