Laserfiche WebLink
C. Dean Hubbard <br /> October 13, 2006 <br /> Page 7 <br /> f) Geomatrix used a value of 3048 cm for the building floor width and length, and 457 cm <br /> for the height of building without providing any justification or reference (please refer to <br /> my comment in section Future Land Use). The default values for industrial/commercial <br /> scenario are 1000 cm for length and width, and 366 cm for height. I used the defaults in <br /> my calculations. <br /> g) Geomatrix used an Indoor Air Exchange Ratio of 0.83. I used the recommended default <br /> of 1.0. <br /> h) Geomatrix calculated indoor air concentrations for: acenaphthene, acenapthylene (used <br /> acenaphthene as a surrogate), fluorene, naphthalene, and pyrene. However, anthracene, <br /> benzo(b)fluoranthene, chrysene, and phenanthrene should also be included. I used pyrene <br /> as a surrogate for phenanthrene due to the higher Henry's Law constant of the former and <br /> their similar chemical structure. Alternatively, Geomatrix could add phenanthrene to the <br /> spreadsheet VLOOK table and model its indoor concentration. Also, I modified the J&E <br /> spreadsheet to add anthracene. <br /> In the absence of soil-gas data, I ran the SL_ADV spreadsheet following the consultant <br /> approach with the exceptions described above. Please be aware that this modeling evaluates the <br /> indoor air concentrations due to migration of vapor from the top 10 feet bgs of soil only and <br /> might underestimate the corresponding risk and hazard. Considering the level of detail and <br /> issues,I recommend collecting soil-gas data to reduce uncertainty in modeling the indoor air <br /> concentrations. <br /> The indoor air concentrations modeled by me are provided in the table below: <br /> Calculated Indoor Air Concentrations for the Volatile Chemicals of Potential Concern <br /> Chemical Soil Concentrations, Indoor Air <br /> in µg/kg Concentrations, <br /> in Mg/M3 <br /> Acenaphthene 460 1.55E-06 <br /> Acenaphthylene* 170 5.74E-07 <br /> Anthracene 110 2.32E-08 <br /> Benzo(b)fluoranthene 350 3.16E-09 <br /> Chrysene 1,090 2.73E-08 <br /> Fluorene 1,330 9.42E-07 <br /> Naphthalene 1,510 6.42E-05 <br /> Phenanthrene** 2,610 3.43E-08 <br /> Pyrene 920 1.21E-08 <br /> Notes: <br />