Redistribution of forms of zinc, cadmium and nickel in soils treated with EDTA

Redistribution of zinc, cadmium, and lead among soil fractions in a sandy calcareous soil due to application of poultry litter

“…Metals from anthropogenic sources also tend to be more mobile than those from pedogenic or lithogenic sources (Chlopecka et al 1996). Organic amendments are added for their beneficial effects on soil chemical and physical properties, as well as a means of disposing of wastes (Li and Shuman 1996). Poultry litter is a valuable source of major plant nutrients and has been used as a soil amendment in agriculture.…”

“…Identification of the chemical forms in which the metals are retained in the soil is helpful to predict their potential mobility to water sources, their plant availability, and the amount of metal cycling through the food chain (Mbila et al 2001). Heavy metals in soil are considered to be distributed among several phases; these include soil solution phase, exchange phase, organic matter phase, carbonate phase, occluded in oxides and secondary clay minerals phase, and residual within the primary mineral lattice phase (Li and Shuman 1996;Speir et al 2003). The water-soluble plus exchangeable metal fraction characterizes the most mobile and immediately bioavailable forms for plant uptake (Li and Shuman 1997).…”

Changes in chemical forms of lead in temperate and semiarid soils in sterile and unsterile conditions

“…Heavy metals in soil are considered to be distributed among several phases, which include water-soluble phase, exchangeable phase, organic associated phase, carbonate associated phase, bound and occluded in oxides and secondary clay minerals phase and residual (Res) within the primary mineral lattice phase (Li and Shuman 1996). Water soluble and exchangeable fractions are considered readily mobile and bioavailable, whereas other metal fractions, especially a RES fraction, are considered immobile and tightly bound, and may not be expected to be released under natural conditions.…”

Chelating Agents in the Environment

“…Elevated concentrations of chelating agents enhance the transport of metals (e.g. Zn, Cd, Ni, Cr, Cu, Pb, and Fe) in soils (101)(102)(103)(104)(105)(106)(107) and enhance the undesired transport of radioactive metals away from disposal sites (10,81,(108)(109)(110). Low concentrations of chelating agents may either stimulate planktic algae growth or decrease it while high concentrations inhibit activity (111)(112)(113).…”