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} <br /> i <br /> s <br /> 3 <br /> r � � <br /> I <br /> r <br /> ppASRS OF CONTAKINATION <br /> w <br /> The inadvertant release of contaminants to the subs=face <br /> can lead to four phases of degradation to the underlying ground ; <br /> water environment. These four phases consist of the following: <br /> ° The adsorbed phase of contamination is the volume of <br /> contaminant that is adsorbed by the soil matrix. The <br /> amount of contaminants adsorbed depends on the grain � <br /> size of the 3.mpacted soils. The higher the silt and ; <br /> clay content the greater the volume of contaminants g <br /> adsorbed. Typically 60 - 80 percent of a loss can be <br /> adsorbed by the underlying soils. The adsorbed phase <br /> can be the source for vapors and/or a dissolved <br /> concentration phase. Subsequent to development of a <br /> free product phase or dissolved .phase 'the adsorptive <br /> capacity of the soils must be exceeded. <br /> The free product phase of contamination consists of the <br /> contaminant that exceeds the adsorbtive capacity of the <br /> soils and collects atop the water table or an <br /> underlying in permeable soil horizon (compacted silts <br /> or clays) . The volume of free product depends upon the <br /> 4 <br /> in-tial amount of loss, depth to product barrier (water <br /> table, low permeable soils) , adsortive capacity of 4 <br /> sub soils, and length of time contaminants were exposed <br /> to the subsurface. in some cases, the type of <br /> r <br /> contaminant ni.-ay be immiciable in water and free product <br /> phase acids to the magnitude of dissolved contaminant <br /> concentration and/or vapor phase plume. <br /> a The dis olv c' hh;c consituent of a subsurface impact <br /> depends cn the volume loss, length of time in contact <br /> with the west,.,r table, and types of contaminant, The <br /> dissolved prig s : tends to travel faster than the free <br /> product }7h` 111fi typically is the first sign of <br />