Trace element mobility

The geology not only provides the chemical source for trace-element mobility but it also provides the physical framework for water-flow paths. The structural properties of the rocks, the porosity, permeable fractures, provide for water-mineral reaction and element mobility. The geomorphology contributes to water-table levels, aquifer permeability, surface-water travel times, and time periods for erosion and sediment transport. Examples of... 

This contribution summarizes state-of-the-science with respect to USGS research on the hydrogeochemistry of trace-element mobilization and attenuation from mineralized areas during transport in surface and ground waters. The primary aspects are ... 

Gerritse RG, Vriesema R, Dalenberg J, et al. 1982. Effect of sewage sludge on trace element mobility in soils. Journal of Environmental Quality 7 359-364. 

La Force, M.J., Fendorf, S.E., Li, G.C. et al. (1998) A laboratory evaluation of trace element mobility from flooding and nutrient loading of Coeur d Alene River sediments. Journal of Environmental Quality, 27(2), 318-28. 

Mass Balance Considerations. The values of ER for the Fischer assay spent shale are contained in Table V. If it is assumed that the relative standard deviation in the analyses is 10%, then the relative probable error in ER would be 14% if the analytical errors were indeterminant and 20% if the errors were determinant (38). The mass ratio of OS-l/FS is 1.24 as derived from the assay data in Table I. It is not possible to conclude that any trace elements are mobilized from the solid material during the assay retorting. The ER results obtained for arsenic, selenium, and molybdenum indicate the importance of analytical precision in detecting any trace element mobilization during oil shale retorting. The values of RI contained in Table V show a similar dependence on analytical precision. The probable errors in these values are also between 14 and 20% if the relative standard deviation in the analytical results is assumed to be 10%. These results indicate that, within experimental error, none of the trace elements have been lost during Fischer assay. More definitive conclusions on whether elements are mobilized or lost can only be reached with more precise analytical... 

Leaching and extraction tests are used widely to assess trace element mobility and phytoavailability, as reviewed by Krishnamurti and Naidu hi Chapter 11. 

Leaching and extraction tests are widely used for assessing trace element mobility and phytoavailability. As measurements in these protocols are made in equilibrium conditions, only thermodynamic information is obtained. However, kinetic extraction—desorption studies are a more correct approximation to the distribution of species in natural media. The desorption rate constants of the trace elements in sediments and soils can be related to their mobility and toxicity. Detailed studies are needed in this area. 

Pueyo, M., Sastre, J., Herndndez, E., Vidal, M., Ldpez-Sdnchez, J. F., and Rauret, G. (2003). Prediction of trace element mobility in contaminated soils by sequential extraction. J. Environ. Qual. 32, 2054-2066. 

Zhu, C., Sanders, S., and Rafal, M., 1993. Modeling coprecipitation reactions as the control of trace elements mobility in groundwater. Geol. Soc. Am. Abstr. with Programs, v. 25, no. 6, A-376. 

Seyfried WE Jr (1987) Experimental and theoretical constraints on hydrothermal alteration processes at mid-ocean ridges. Ann Rev Earth Planet Sci 15 317-335 Seyfried WE Jr, Chen X, Chan L-H (1998) Trace element mobility and lithium exchange during hydrothermal alteration of seafloor weathered basalt an experimental study at 350°C, 500 bars. Geochim Cosmochim Acta 62 949-960... 

Smith and Huyck (1999) described metal mobility under different environmental conditions. Although it is rather difficult to predict trace element mobility in soils and other terrestrial compartments, these authors referred to the capacity of an element to move within fluids after dissolution in surfi-cial environments. The following conditions and behavior of trace elements were distinguished ... 

In general, in heavy neutral soils most trace elements would be less mobile and less phytoavailable than in light acid soils. Trace element mobility in soils is also known to be related to land use. Usually, metals in forest soils are more easily mobile, and therefore easier bioavailable and leached, than are trace elements in agricultural soils. This phenomenon will be an environmental concern in the future due to programs of forestation of poor agricultural quality soils, especially in Central and Eastern Europe. 

Van der Sloot HA, de Groot GJ, Eggenkamp HGM, Tielen JALW and Wijkstra J (1987) Versatile Method for the Measurement of the Trace Element Mobilities in Waste Materials, Soils and Bottom-Sediments. Stichting Energie Onderzoek Centrum, Petten, Netherlands, ECN-87-085. 

A special case of trace element mobilization is in the dehydration of subducted. ocean floor, a process thought to be pertinent to the generation of caIc-alkaU f magmas. Pearce (1983) has suggested that the elements Sr, K, Rb, Ba, Th, Ce, P -and Sm may. be mobile in such circumstances.,. . 

Jarvis 1. and Higgs N. (1987) Trace-element mobility during early diagenesis in distal turbidites late Quaternary of the Madeira Abyssal Plain, N. Atlantic. Geology and Geochemistry of Abyssal Plains, 31(ed. P. P. E. Weaver, J. Thomson,), Geological Society Special Publication London, pp. 179-214. 

---