Heavy metals soil contamination from

Bradley RW, Morris JR. 1986. Heavy metals in fish from a series of metal-contaminated lakes near Sudbury, Ontario. Water Air Soil Pollut 27 341-354. 

The acid extraction treatment system (AETS) reduces the concentrations and/or leachability of heavy metals in contaminated soils so that the soils can be returned to the original site. The main application of the AETS is to extract heavy metals from soils. Additional applications of the AETS include treatment of contaminated sediments, sludges, and other heavy-metal-containing solids. 

ENSR International Group soil cleaning process is an ex situ treatment for soils contaminated with petroleum hydrocarbons. The process uses a combination of soil washing and solvent extraction. Soil washing removes heavy metals and hydrocarbons from coarse soil particles, resulting in a reduced volume of material to be treated by solvent extraction. Solvent extraction uses a chemical additive that enhances the extraction of hydrocarbons from soil particles in an aqueous slurry. 

According to the vendor, the HP-80 technology is effective in removing heavy metals and acids from hydrocarbon-contaminated soil however, these substances cannibalize the HP-80 compound and higher concentrations of the HP-80 are necessary (3 to 5% by volume instead of 1%). 

Theodoratos, P., Papassiopi, N. Xenidis, A. 2002. Evaluation of monobasic calcium phosphate for the immobilization of heavy metals in contaminated soils from Lavrion. Journal of Hazardous Materials, 94, 135-146. 

A particular aspect of water treatment is the rehabilitation of accidentally contaminated soils by radionuclides. This is well illustrated by the works carried out after the Cernobyl catastrophe. The incorporation of clinoptilolite into contaminated soils reduced the transport of heavy metals and radionuclides from soils into ground water and biomass (7). Union Carbide s IONSIV EE-95 (CHA) and A-51 zeolites (LTA) with excellent Cs+/Na+ and Sr2+/Na+ selectivities, respectively, have also been employed for decontamination of high activity level water in the reactor containment building from Cs+ and Sr2+ after the accident at Three Miles Island (5). The radioisotope loaded zeolites were then transformed into glasses for ultimate disposal. 

A series of laboratory experiments involving simple, ultrasonic, EK, and EK-ultrasonic flushing tests for the treatment and removal of heavy metals and hydrocarbons from contaminated groundwater in sandy layers under a river bank were also carried out by Chung (2007). The test results showed that the EK-ultrasonic flushing technique is the most effective one for the removal of heavy metals and hydrocarbon from contaminated sandy layers. It was also found that the EK process is the most effective one to enhance the removal efficiency of heavy metals (e.g., Cd) from contaminated sandy soil under the river bank. On the other hand, the ultrasonic technique is the most effective one to enhance the removal efficiency of hydrocarbon contaminants (e.g., diesel fuel) from contaminated soil. 

Heavy metals such as cadmium, lead, iron, and zinc, in their metallic state, corrode and form salts and bases, which take up cationic sites on soil particles. In some cases, land is often contaminated from the spillage of heavy metal ions directly from aqueous plating shop wastes or airborne pollution from metal smelters. Soil has the capacity to immobilize signihcant quantities of heavy metal ions, to the 2%-3% level in some cases, such as the top soil around lead smelters. 

Ciassification Organo-sulfur polymer Uses Precipitant for removal of heavy metals from process wastewater, ground waters, and other polar soivs. stabilizer for detoxification and stabilization of heavy metals in contaminated solids, such as soils, sludges, ash and sediments... 

F. Awad and V. Rdmheld, Mobilization of heavy metals from contaminated calcareous soils by plant-borne chelators and its uptake by wheat plants. J. Plant Nutr. 23 (2000) in press. 

Biological activity can be used in two ways for the bioremediation of metal-contaminated soils to immobilize the contaminants in situ or to remove them permanently from the soil matrix, depending on the properties of the reduced elements. Chromium and uranium are typical candidates for in situ immobilization processes. The bioreduction of Cr(VI) and Ur(VI) transforms highly soluble ions such as CrO and UO + to insoluble solid compounds, such as Cr(OH)3 and U02. The selenate anions SeO are also reduced to insoluble elemental selenium Se°. Bioprecipitation of heavy metals, such as Pb, Cd, and Zn, in the form of sulfides, is another in situ immobilization option that exploits the metabolic activity of sulfate-reducing bacteria without altering the valence state of metals. The removal of contaminants from the soil matrix is the most appropriate remediation strategy when bioreduction results in species that are more soluble compared to the initial oxidized element. This is the case for As(V) and Pu(IV), which are transformed to the more soluble As(III) and Pu(III) forms. This treatment option presupposes an installation for the efficient recovery and treatment of the aqueous phase containing the solubilized contaminants. 

Phytoextraction has several advantages. The contaminants are permanently removed from the soil and the quantity of the waste material produced is substantially decreased. In some cases, the contaminant can be recycled from the contaminated biomass. However, the use of hyperaccumul-ating plants is limited by their slow growth, shallow root systems, and small biomass production. In order for this remediation scheme to be feasible, plants must tolerate high metal concentrations, extract large concentrations of heavy metals into their roots, translocate them into the surface biomass, and produce a large quantity of plant biomass. 

Neale, C.N., Bricka, R.M. and Chao, A.C., Evaluating acids and chelating agents for removing heavy metals from contaminated soils, Environ. Progr., 16, 274-280, 1997. 

Peters, R.W., Chelant extraction of heavy metals from contaminated soils, J. Hazard. Mater., 66, 151-210, 1999. 

Electroosmotic soil processing is an in situ separation/removal technique for extracting heavy metals and organic contaminants from soils.17 55 89 The fluid between the soil particles moves because a constant, low DC current is applied through electrodes inserted into the soil mass. The electroosmosis (EO) remedial method provides an advantage over conventional pumping techniques for in situ treatment of contaminated fine-grained soils and is more efficient in saturated conditions. 

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