Laserfiche WebLink
i <br /> Table 3. Initial Conditions for Soil:Li uid Ratio Tests <br /> Soil:Liquid COMP7 IP Ground- 30% H702 Initial <br /> Ratio Soil, g water, mL added, mL H2O2, % <br /> Ozone Only <br /> 1 1 75 75 0 0 <br /> 1 2 75 150 0 0 <br /> 1 5 75 375 0 0 <br /> Peroxone <br /> 1 1 75 75 1 25 05 <br /> 12 75 150 25 05 <br /> 1 5 1 75 1 375 1 625 1 05 <br /> 2.6.2 Total Cr(VI) Reducing Capacity of Soil (Walkley-Black TOC Method) <br /> To estimate the total amount of Cr(VI) that can be reduced by site soil, the total Cr(VI) <br /> reducing capacity of soil (Bartlett, 1991)was measured This test is the same as the <br /> Walkley-Black method of measuring total organic carbon (TOC) Specifically, 10 g of <br /> COMP7 soil were combined with 35 mL of concentrated sulfuric acid (—98%H2SO4) <br /> and 10 mL of 0 56 moles/literCr(VI) (added in the form of potassium dichromate, <br /> • K2Cr2O7) A blank containing reagents but no soil was also run After about 60 minutes, <br /> 240 mL of deiomzed water was added The solution was cooled to room temperature, <br /> then the concentration of Cr(III) formed was determined by measuring the absorbance of <br /> the aqueous phase at 600 nanometers using a Hach DR 2010 Spectrophotometer and <br /> comparing the result to the absorbance of Cr(IH) standards The total reducing capacity <br /> of the soil was performed on both field moist COMP7 soil (soil samples in the condition <br /> in which they were stored) and air-dned COMP7 soil (soil samples that were exposed to <br /> air to allow hydrocarbons to volatize in order to mimic background or unimpacted soil <br /> conditions) Both field moist and air-dned soil were tested to assess whether the Cr(VI) <br /> reducing capacity of the soil is affected by the presence hydrocarbons, which would be <br /> destroyed in the treated areas of the site, but present in locations downgradient of the <br /> treated area Air-dned soil was used because background soil was not available for this <br /> test <br /> The total Cr(VI) reducing capacity was calculated as follows <br /> Cr(VI) Reducing Capacity(gg/kg soil) = <br /> gg/L Cr(III) formed x (0 285 L/ 0 01 kg) Eqn 7 <br /> 2.6.3 Available Cr(VI) Reducing Capacity (Bartlett Method) <br /> The available Cr(VI) reducing capacity of soil, as defined by Bartlett (1991), was <br /> measured This test was conducted on field moist and air-dned COMP7 soil Air-dried <br /> soil was tested to determine whether hydrocarbons present in field moist soil contributed <br /> significantly to the available Cr(VI) reducing capacity This was important because <br /> PRIMA Environmental 8 Eva]of Peroxone <br /> June 1,2005 ET1C-Exxon#3942 <br />