Arsenic and lead release from fly ash stabilized/solidified soils under modified semi-dynamic leaching conditions.
A fly ash-based stabilization/solidification (S/S) technique was investigated using field soil samples contaminated with arsenic (As) and lead (Pb). A semi-dynamic leaching test was used to evaluate the effectiveness of the S/S treatment. By assessing the cumulative fractions of leached As and Pb, the effective diffusion coefficient (D(e)) and a leachability index (LX) were measured and used for evaluating the effectiveness of the S/S treatment. Overall, As release was reduced by 98.3% and Pb release was reduced by 98.5% upon addition of 25% Class C fly ash. The mean D(e) decreased significantly and the mean LX was always above 9 for all treated samples, indicating that the treated soils were acceptable for "controlled utilization". The mechanism controlling As leaching from all treated samples appeared to be a mixture of wash-off and diffusion. Diffusive As release was proportional to fly ash content. The mechanism controlling Pb leaching when samples were treated with 25% fly ash appeared to be wash-off.
Moon
Deok Hyun
DH
W.M. Keck Geoenvironmental Laboratory, Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, USA. dmoon@stevens.edu
Dermatas
Dimitris
D
D001151:Arsenic / Q000032:analysis / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D060729:Coal Ash; D052918:Environmental Restoration and Remediation / Q000379:methods; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000032:analysis / Q000737:chemistry*; D052638:Particulate Matter / Q000737:chemistry*; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D060729:Coal Ash; D052638:Particulate Matter; D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D007854:Lead; D002244:Carbon; D001151:Arsenic