health and safety plan solid waste management unit assessment

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STODDARD SOLVENT 67-9
TABLE 67-l
rd Solvent
Carbon Range G-C12
Straight/Branched Alkanes 48%
Cycloalkanes 38%
Aromatics
Benzenes
Alkylbenzenes
Indans/Tetralins
0.1%
14%
< 1%
hydrocarbons in a typical Stoddard solvent sample. Table 67-2
identifies the selected hydrocarbons and presents the predicted
partitioning of low soil concentrations of those hydrocarbons among
soil particles, soil water, and soil air. The portions associated with
the water and air phases of the soil are expected to have higher
mobility than the adsorbed portion.
Estimates for the unsaturated topsoil indicate that sorption is
expected to be an important process for all the dominant hydrocarbon
categories. Partitioning to the soil-vapor phase in this model is not
very important for the C,-C,, hydrocarbons. The allcyl benzenes have
higher water solubilities and transport with infiltrating water may be
important for these compounds; volatilization is still expected to be
low. In saturated, deep soils '(containing no soil air and negligible
soil organic carbon), a significant percent of the aromatic
hydrocarbons is predicted to be present in the soil-water phase and
available for transport with flowing ground water.
In interpreting these results, it must be remembered that this
model is valid only for low soil concentrations (below \aqueous
solubility) of the components. Large releases of solvent (spills,
leaking underground storage tanks) may exceed the sorptive capacity of
the soil, thereby filling the pore spaces of the soil. In this
situation, the hydrocarbon mixture would move as a bulk fluid and the
equilibrium partitioning model would not be applicable.
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