Apparent soil-water distribution

To describe the effects of coipled sorption processes on the phase distribution of HOCs in sur ctant-soil systrans, an apparent soil-water... 

Apparently, there are many studies about the distribution, content, transfer, and transformation of carbon in sediment or soil to be performed. As one of three interdependent basic links in sediment (including soil-water-atmosphere systems), marine sediment plays an important role in oceanic or global environments. From now on, more attention should be paid to research into the functions of sediments in carbon biogeochemical cycles (Sun and Song, 2002). 

Electrical conductivity (or its mathematical inverse, resistivity) of a soil solution is strongly correlated with total salt content. Therefore, laboratory methods involving solution or saturated paste conductivity are often used to assess soil salinity. Electrical conductivity measurements of bulk soil (designated as ECa for apparent electrical conductivity) were also first used to assess salinity. Resistivity and conductivity measurements are also useful for estimating other soil properties, as reviewed by and. Factors that influence ECa include soil salinity, clay content and cation exchange capacity (CEC), clay mineralogy, soil pore size and distribution, soil moisture content, and temperature. ° For saline soils, most of the variation in ECa can be related to salt concentration. In non-saline soils, conductivity variations are primarily a function of soil texture, moisture content, bulk density, and CEC. The theoretical basis for the relationship between ECa and soil physical properties has been described by a model where ECa was a function of soil water content (both the mobile and immobile fractions), the electrical conductivity of the soil water, soil bulk density, and the electrical conductivity of the soil solid phase.Later, this model was used to predict the expected correlation structure between ECa data and multiple soil properties. ... 

Adams, F., Burmester, C., Hue, N. V., and Long, F. L. (1980). Comparison of column-displacement and centrifuge methods for obtaining soil solution. Soil Sci. Soc. Am. J. 44, 733—735. Amoozegar-Fard, A. D., Nielsen, D. R., and Warrick, A. W. (1982). Soil solute concentration distribution for spatially varying pore water velocities and apparent diffusion coefficients. Soil Sci. Soc. Am.J. 46, 3—9. 

The advantage of using fugacity to calculate the equilibrium distribution coefficients becomes apparent when one compares the fugacity capacities of a HOP for several different phases. For example, consider a region of the unsaturated zone just below the ground surface where naphthalene is distributed between air, water, pure phase octanol, and soil at equilibrium. The fugacity capacities for these phases are repeated below in Eqs. (46)-(49) ... 

Compounds released to the environment distribute among the major environmental compartments, air, water, soil, and biota as a function of their physical chemical properties and models can provide a basis to predict how different compounds behave. Adverse effects will depend on persistence in a compartment. In this context, it is readily apparent that the hydroxyl radical serves as a very efficient atmospheric scavenger. Other oxidants may show activity with a limited series of compounds, but the hydroxyl radical is unique in the broad range of organic compounds with which it reacts and the rates at which these reactions proceed. Lifetimes for selected compounds based on reactions with the hydroxyl radical are compiled in Table 6.28. 

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