EPA On-line Tools for Site Assessment Calculation
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Bulk Density Result
|With porosity of 0.35, the bulk density is 1.72 g/cm3. This contrasts with the value of 2.65 g/cm3 used in the report. The value of 2.65 g/cm3 is the solid density of quartz, a value that you should remember.|
The bulk density is the density of a unit volume of the aquifer that includes the solids and the void space. Thus the bulk density must be lower than the solid density, as it is defined by
where rb is the bulk density, rs is the solid density (2.65 g/cm3, and q is the porosity.
Sorption and Fraction Organic Carbon
The amount of sorption is usually determined from the use of a retardation factor. The retardation factor depends on a chemical-specific property, the organic carbon partition coefficient, Koc and an aquifer-specific property, the fraction organic carbon, foc.
The calculation is made from the formula:
where R is the retardation factor, rb is the bulk density, and q is the porosity.
Koc is normally obtained from the literature, and foc from a site-specific measurement, but was not reported for this site. Geologists familar with the formation indicated, however, that an foc of 0.0001 would be reasonable, because the aquifer consists of a clean sand.
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