Nickel, Lead, Cadmium, and Chromium Concentrations in Shoots of Maize Grown in Acidic Soil Amended with Coal Combustion Byproducts

Abstract

Large quantities of coal combustion by-products (CCBs) are produced when power plants bum coal to generate electricity. The CCBs are disposed, usually in landfills, unless used beneficially. One beneficial use of CCBs could be application to agncuttural/ pasture/forest land. However, concerns exist for trace metal accumulation in plants when CCBs are applied to soil. Concentrations of Ni, Pb, Cd, and Cr in shoots of maize (Zea muys L.) grown (greenhouse) in acidic soil (Umbric Dystrochrept, pHc, = 3.9) amended with 15 CCBs at different levels are provided. The CCBs used were two fly ashes (FAs), three fluidized bed combustion (FBC) by-products, one Ca oxide (CaO) material, six high sulfite (CaS03) flue gas desuffurization (FGD) by-products, and t h e high sulfate (CaSO,) FGD by-products. Chemical grade CaSO,, CaSOb, and CaC03 (lime) at different levels were also included in experiments. Because of the large number of materials tested and the various levels for each material tested, several experiments were conducted over time and each experiment had unamended and limed (different levels) soil. Mean shoot concentrations of Ni, Pb, Cd, and Cr in maize varied considerably depending on the CCB used to amend soil. Overall mean concentrations of Ni, Pb, Cd, and Cr in shoots of young maize were 1.47 for Ni, 1.38 for Pb, 0.32 for Cd, and 0.50 for Cr in rngkg-', and were not above those considered normal for plant tissue. Loading in soil might be of concern if CCBs are continually added to the same soil over long Periods of time.