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Metals in waste foundry sands and an evaluation of their leaching and transport to groundwater

Alves, B.S.Q. and Dungan, R.S. and Carnin, R.L.P and Galvez, R. and de Carvalho Pinto, C.R.S. (2014) Metals in waste foundry sands and an evaluation of their leaching and transport to groundwater. Water, Air, & Soil Pollution. 225(Article 1963).

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While most waste molding foundry sands (WFSs) are not hazardous in nature, regulatory agencies are often reluctant to permit their beneficial use in agricultural and geotechnical applications due to concerns over metal leaching. The objective of this study was to quantify total and Toxicity Characteristic Leaching Procedure (TCLP) metals in 16 waste sands from Brazilian ferrous foundries and assess their potential to leach metals to groundwater using a probabilistic model developed by the U.S. EPA. Total and TCLP metal concentrations in the non-hazardous sands fell within ranges as reported in the literature, although some of the leachate concentrations were found to exceed drinking water and groundwater maximum contaminant levels MCLs. Leachate values above the MCLs were then used in the model to estimate groundwater concentrations at hypothetical wells up to 400 m downgradient from the land application unit. A conservative scenario of one hectare of land applied WFS and high annual rainfall totals (> 1219 mm/year) suggested that groundwater concentrations of Ba, Hg, Mn, Ni, and Pb could potentially exceed health-based MCLs at most wells. Compared to moderate rainfall totals (813–1016 mm/year), the model demonstrated that wet climates can exacerbate the transport of metals from unconsolidated applications of WFS; however, the use of TCLP results as model input values is not considered appropriate for most byproduct beneficial use scenarios since it simulates low pH conditions within a municipal landfill.

Item Type: Article
NWISRL Publication Number: 1494
Subjects: Soil > Amendments > Foundry sand
Depositing User: Users 6 not found.
Date Deposited: 19 Jun 2014 17:11
Last Modified: 19 Jun 2014 17:11
Item ID: 1537