ARCHIVED REPORTS_XR0008213 - Laserfiche WebLink

Home Browse Search

or other receptors, only the leachable fraction of a solid waste presents a potential threat to groundwater Therefore, the DLM specifies the LF of a solid by the formula LF = TotalConcentration Leachable ConstituentConcentration(i) (1) The WET extract must be multiplied by 10 to account for dilution during the extraction procedure As explained in the DLM, the LF is used to evaluate the water solubility of constituents in solid wastes According to the formula presented above, high values of LF indicate insoluble constituents, whereas LF values approaching 1 0 indicate soluble constituents Diesel oil is a refuted hydrocarbon product which contains hundreds of short- and long-cham hydrocarbons Naphthalene is a primary constituent, present in relatively large amounts (up to 1% by weight) in fresh diesel oil Because of its chemical properties, naphthalene is considered to be the most mobile constituent of diesel oil. Therefore, naphthalene was analyzed in total and WET extracts as the "worst case" or most mobile indicator constituent of diesel oil As diesel oil in soils weathers and degrades, the percentage of naphthalene in diesel declines This occurs because the majority of diesel constituents are complex polynuclear aromatic hydrocarbons which adsorb strongly to soil surfaces and are resistant to degradation Table 2 presents the results for total and WET extractable analyses of the selected soil samples with TPH-d concentrations in excess of 1,000 mg/kg Only TPH-d and naphthalene were detectable in both the total and WET extract samples Therefore, Table 2 suggests that much of the diesel present in these soil samples is immobile and insoluble, with LF values of 368 and 1,267 The LF value can be recalculated as the percentage of leachable versus total concentration of any constituent The inverse of the LF — or 1/LF x 100 — is the percentage of soluble versus total constituent For the soil sample from DMW-5 at 26 feet bgs (LF = 368) the percentage of soluble TPH-d is 0 27% For the soil sample from SB-20 at 21 feet bgs (LF = 1,267), the percent soluble TPH-d is 0 079% Expressing the inverse of the LF is more intuitive because it indicates that 99 73 to 99 921% of the TPH-d is insoluble in water LF values for naphthalene were 36 and >65 (Table 2) Total concentration of naphthalene in soils at the site is low (G 5 mg/kg) The results suggest that soil adsorption and biodegradation will sufficiently attenuate napthalene in the unsaturated zone 5AC156 14 g DAMES &I OGRE