Geochemical migration

Table 8. Bio geochemical migration rates of heavy metals in the Spruce Forest ecosystems, Karelia, Russia.

Wang, X. Q. 2005. Conceptual model of deep-penetrating geochemical migration. Geological Bulletin of China, 24, 892-896 (in... 

Acid deposition influence on the bio geochemical migration of heavy metals in the food web... 

Golubev VS, Garibyants AA (1971) Heterogeneous processes of geochemical migration. Plenum (translated from Russian), 150 p... 

Yanase N, Payne TE, Sekine K (1995) Groundwater geochemistry in the Koongarra ore deposit, Australia 2. Activity ratios and migration mechanisms of uranium series nuclides. Geochem J 29 31-54... 

The geochemical interactions possible between an injected waste and the reservoir rock and its associated fluids can be quite complex. Thus a combination of computer modeling, laboratory experimentation, and field observation will inevitably be necessary to satisfy current regulatory requirements for a geochemical no-migration deep-well injection. This section covers the computer methods and models available for predicting geochemical fate. 

This case study is interesting in that one hazardous waste (acrylonitrile) was quickly rendered nonhazardous after injection, whereas another (sodium thiocyanate) showed no evidence of decomposition during the duration of the study. The implication for geochemical fate assessment is that research should focus on the compounds likely to be most resistant to decomposition or immobilization, as they will be the ones most critical in demonstrating containment in a no-migration petition. 

Mckenzie, D.J., Injection of Acidic Industrial Waste into the Roridan Aquifer near Belle Glade, Florida Upward Migration and Geochemical Interactions, U.S. Geological Survey Open File Report 76-626, 1976. 

Figure 1. Schematic illustration of factors influencing the production and migration of radon in soils and into buildings. Geochemical processes affect the radium concentration in the soil. The emanating fraction is principally dependent upon soil moisture (1 0) and the size distribution of the soil grains (d). Diffusion of radon through the soil is affected primarily by soil porosity ( ) and moisture content, while convective flow of radon-bearing soil gas depends mainly upon the air permeability (k) of the soil and the pressure gradient (VP) established by the building.

Baker, E.G. (1967) A geochemical evaluation of petroleum migration and accumulation. In Fundamental Aspects of Petroleum Geochemistry. Nagy, B., Colombo, V. Eds., pp. 299-330, Elsevier, New York, New York. 

Figure 4. Simplified geochemical explanation of U migration in an aquifer.

Sorption can significantly diminish the mobility of certain dissolved components in solution, especially those present in minor amounts. Sorption, for example, may retard the spread of radionuclides near a radioactive waste repository or the migration of contaminants away from a polluting landfill (see Chapters 21 and 32). In acid mine drainages, ferric oxide sorbs heavy metals from surface water, helping limit their downstream movement (see Chapter 31). A geochemical model useful in investigating such cases must provide an accurate assessment of the effects of surface reactions. 

Many times in geochemical modeling we want to understand not only what reactions proceed in an open chemical system, but where they take place (e.g., Steefel et al., 2005). In a problem of groundwater contamination, for example, we may wish to know not only the extent to which a contaminant might sorb, precipitate, or degrade, but how far it will migrate before doing so. 

Two hundred and fifty three till (C-horizon) samples were collected and analyzed to detemine suitable analytical methods to delineate till geochemical signatures that reflect Zn-Pb-Ag mineralization and to determine possible pathways of element migration from the bedrock to till. Results of a study conducted at the Mount Fronsac North deposit are discussed here. 

Environmental assessments of open-pit mines include an understanding of geochemical processes, which control production of acidity and migration of metals (Davis Ashenberg 1998, MEND 1991). 

Geochemical conditions of tropical soils favor the biogeochemical migration of iron and manganese. The turnover of other metals is from 1.1 g/ha/yr for Cd to 1,050.0 g/ha/yr for Sr with the relevant rates of exposure to living organisms. 

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