Organic phase, soil

The solubihty of hydrophobic substances in, or their absorbabiUty on suspended particles, on sediments, on biota, or on soil particles can be related to the solubihty of these substances in organic solvents. The solvent -octanol, CH2(CH2)yOH, is a kind of surrogate for many kinds of environmental and physiological organic substances and has become a reference phase for organic phase water partitioning of organic solutes. 

As an immiscible organic liquid retained by capillary forces in the pore space between the soil particles. This free organic phase is often referred to with the abbreviation NAPL (nonaqueous phase liquid). 

Step 2 Calculate the initial distribution oftoluene in the subsurface. The initial distribution of toluene can be calculated using equations 1 to 5 from Table 14.3 and taking into consideration that the organic phase is a pure compound, i.e., X = 1, m = 1, and y = 1. The total quantity of contaminant per unit soil Ct can be estimated from the known amount of spill Afspill and the volume of the contaminated zone ... 

Soil solution is the aqueous phase of soil. It is in the pore space of soils and includes soil water and soluble constituents, such as dissolved inorganic ions and dissolved organic solutes. Soil solution accommodates and nourishes many surface and solution reactions and soil processes, such as soil formation and decomposition of organic matter. Soil solution provides the source and a channel for movement and transport of nutrients and trace elements and regulates their bioavailability in soils to plants. Trace element uptake by organisms and transport in natural systems typically occurs through the solution phase (Traina and Laperche, 1999). 

Adsorption of nonionic compounds on subsurface solid phases is subject to a series of mechanisms such as protonation, water bridging, cation bridging, ligand exchange, hydrogen bonding, and van der Waals interactions. Hasset and Banwart (1989) consider that the sorption of nonpolar organics by soils is due to enthalpy-related and entropy-related adsorption forces. 

Kaiser, K. Zech,W. (1997) Competitive sorption of dissolved organic matter fractions to soils and related mineral phases. Soil Sci. 

T0260 ENSR International Group, Soil Cleaning Process T0266 Envirogen, Inc., Solid Organic-Phase Extraction (SoPE)... 

Furthermore, air-organic solvent partition constants, in particular the air-octanol partition constant, are widely used to evaluate and/or predict the partitioning of organic compounds between air and natural organic phases. Such organic phases are present, for example, in aerosols or soils (Chapters 9 and 11) or as part of biological systems (Chapter 10). 

A measured quantity of soil, sediment, or solid waste sample extracted with a measured volume of water, aqueous solution pH adjusted to >11 and serially extracted with methylene chloride pyridine partitions into the organic phase, which is then concentrated and analyzed as above. 

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