Laserfiche WebLink
Metadata
Document management portal powered by Laserfiche WebLink 9 © 1998-2015 Laserfiche. All rights reserved.
16 <br /> Based on boring logs provided by your office, the soil at the site consists largely of sandy to silty <br /> clay. Using unit dry densities of 58 pounds per cubic foot (pcf) for a soft clay and 116 pcf for <br /> a dense sand ('Dunn, et al, 1980), an average soil density of 87 pcf was estimated. Applying <br /> this soil density factor to the above two soil volumes results in soil mass quantities of 344,520 <br /> pounds (lbs) and 159,732 lbs, respectively. <br /> D) Since laboratory contaminant concentrations are expressed in metric (SI) units, the above two <br /> soil mass quantities need to be converted to SI units by applying a conversion factor of 2.21 <br /> lbs = 1 kilogram (kg). This results in excavated soil mass quantities of 155,891 kg and 72,277 <br /> kg, respectively. <br /> E) Soil samples of the spoils piles were collected and analyzed for each excavation. According <br /> to data provided by your office, average spoils piles contaminant concentrations were as <br /> follows: <br /> Exc. 1) TPHg: 767 milligrams per kilogram (mg/kg) <br /> TPHd: Not analyzed <br /> Benzene: 8.33 mg/kg <br /> Exc. 2) TPHg: 33 mg/kg <br /> TPHd: 726 mg/kg <br /> Benzene: 0.242 mg/kg <br /> Applying these contaminant concentrations to the mass quantities of excavated soil, the <br /> estimated mass of contaminants excavated are as follows: <br /> Mass TPHg TPHd Benzene <br /> Exc. 1 155,891 kg 119.6 kg NIA 1.30 kg <br /> Exc. 2 72,277 kg 2.39 kg 52.5 kg 0.017 kg <br /> TOTAL 228,168 kg 122.0 kg 52.5 kg 1.32 kg <br /> F) To evaluate relative contaminant reduction and/or degradation, the mass of contaminants <br /> remaining in the unexcavated soil needs to be estimated. This can then be compared to the <br /> mass of the contaminants in the excavated soil. <br /> To evaluate the extent of remaining soil contamination, the soil profile was divided into 5-foot <br /> vertical increments, and the volumetric contaminant mass of each increment calculated. Maps <br /> and boring logs provided by your office depicting the inferred lateral and vertical limits of <br /> contamination were used to estimate the volume of remaining contaminated soil. The total <br /> estimated contaminant mass remaining in the soil would then be the sum of the two <br /> incremental mass volumes. <br /> 1 Dunn, et al, Fundamentals of Geotechnical Analysis, 1980. <br /> 2 <br /> JJW GEOSCIENCES Inc. <br />