Movement of heavy metals

Wolfberg, G.A. Kahanovich, Y Avron, M. Nissenbaum, A. Movement of Heavy Metals into a Shallow Aquifer by leakage from Sewage Oxidation Ponds, Water Res. 1980,14, pp 675-. 

Emmerich, W.E., Lund, L.J., Page, A.L., Chang, A.C., 1982a. Movement of heavy metals in sewage-sludge treated soils. J. Environ. Qual. 11, 174—178. 

For the barrier to prevent the movement of heavy metal cations, it follows that the hydraulic flow velocity of groundwater through the soil (vHyd) should not be greater than the sum of the electroosmotic velocity (veof) plus the electromigration velocity (vion), assuming diffusion is neglected ... 

Toulkes EC, McMullen DM. 1987. Kinetics of transepithelial movement of heavy metals in rat jejunum. Am J Physiol 253 G134-G138. 

Moore, J.W. 1981. Influence of water movements and other factors on distribution and transport of heavy metals in a shallow bay (Canada). Arch. Environ. Contam. Toxicol. 10 715-724. 

The movement of acid-front to the cathode is due to migration (electric potentials), diffusion (chemical potentials), and advection (hydraulic potential) and causes desorption of heavy metals from clay surfaces and transports them into the pore fluid. Electro-osmotic flow and its associated phenomena constitute the mechanisms for removing heavy metals from soils. 

Electrokinetics involves the application of low-level direct current (DC) between electrodes placed in a contaminated area. Different variations of this process were developed to suit the needs of each case. The processes adopted at each site differ with each other in one or many aspects. Basically, two approaches are defined depending on the type of contaminant. The first approach is the enhanced removal in which the contaminants are transported by electromigration and/or by electro-osmosis toward the electrodes for subsequent removal, and the second approach is the treatment without removal, which involves the electroosmotic transport of contaminants through the treatment zones and may also include the frequent reversal of polarity of electrodes to control the direction of contaminant movement (USEPA, 1997). The first approach is applicable for the removal of heavy metals, whereas the second approach was developed for the removal of organic species from contami-... 

The removal of heavy metal ions from both natural water supplies and industrial wastewater streams is becoming increasingly important as awareness of the environmental impact of such pollutants is fiilly realized. In particular, the likelihood of such metal ions precipitating out of solution and/or coating other materials can have a profound effect on both aqueous and nonaqueous environments. There is considerable evidence in the literature that the primary mechanism for transportation of metal contaminants in aquatic systems is the movement of suspended particulate material containing the adsorbed pollutant metals [1,2]. It is also known that a strong correlation exists between the concentration of trace metals in the (aquatic) environment and the extent to which those metal ions adsorb onto colloidal substrates present in the environment [2,3], A similar correlation between the concentration of trace metals in the (aquatic) environment and their precipitation behavior is not so clear. There is, then, a well-founded need to study adsorption-related phenomena in order to understand and predict the behavior of toxic metals in the environment. 

Many agricultural processes such as control of fertilizers and pesticides are influenced by surface and sub-surface movement, percolation and infiltration of water. Stable activateable tracers, such as bromide, analyzed by NAA, have allowed the soil scientist to quantify the distribution of agricultural chemicals under a wide variety of environmental and land use influences. In one of the study on phosphate fertilizers in Egypt using NAA, Abdel-Haleem et al. (2001) have reported the presence of heavy metals Fe, Zn, Co, Cr, and Sc as well as rare earth elements La, Ce, Hf, Eu, Yb and Sm in the samples containing the phosphate fertilizer components (e.g., rock phosphate, limestone, and sulfur) from which fertilizer is produced as final output product. The measurement of Ca/Si concentration ratio in the concrete samples has been carried out using NAA with 5Ci Am-Be neutron source (Khelifi et al. 1999). 

Heavy metal biocides [II, 19.]. Paulus (1993) commented on the decline in the use of heavy metal biocides in general and mercury based biocides in particular. He said that there is a strong movement throughout the world in favour of their substitution in view of their toxicity and especially their ecotoxicity. 

Carrizosa MJ, Hermosin MC, Koskinen WC, Cornejo J (2004) Interactions of two sulfonylurea herbicides with organoclays. Clays Clay Miner 52 643-649 Celis R, Hermosin MC, Cornejo J (2000) Heavy metal adsorption by functionalized clays. Environ Sci Technol 34 4593-4599 Chappell MA, Laird DA, Thompson ML, Li H, Teppen BJ, Johnston CT, Boyd SA (2005) Influence of smectite hydration and swelling on atrazine sorption behavior. Environ. Sci Technol 39 3150-3156 Chiou CT (1989) Theoretical considerations of the partition uptake of nonionic organic compounds by soil organic matter. In Sawhney BL, Brown K (eds) Reactions and movement of organic chemicals in soils. Soil Science Society of America, Madison, WI, pp 1-29... 

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