health and safety plan solid waste management unit assessment

AUTOMOTIVE GASOLINE 65-15
before its intended use. Since it is possible for one gallon of
gasoline containing 1% benzene by volume to contaminate 10 million
liters (2.69 million gallons) of water to the drinking standard of
1 wb. underground gasoline storage tanks are a major environmental
concern (2320).
Many authors have documented ground-water contamination as a
result of hydrocarbon spills. For example, Osgood (2322) reported over
200 hydrocarbon spills in Pennsylvania in a 2.5-year period; in that
time, 14 public water supplies were polluted or threatened, 104 wells
seriously damaged, and one spill resulted in the subsurface discharge
of over 270,000 gallons of gasoline. Matis (2323) reported over 60
cases of ground-water contamination in Maryland from 1969 to 1970.
Drinking water contamination caused by gasoline migration and
subsequent penetration of a subsurface water supply line has also been
reported (2321); the most serious contaminant was ethylene dibromide
(EDB), a gasoline additive. EDB has been reported to be present in
leaded gasoline in sufficient quantities to constitute a threat to
ground water following a gasoline discharge to the environment (2320).
Due to the extensive use of gasoline and its potential for
environmental release during use, storage or transport, several groups
have addressed its fate. The fate of gasoline in the soil environment
is.basically a function of the solubility, volatility, sorption, and
degradation of its major components. The relative importance of each
of these processes is influenced by the type of contamination (e.g.,
surface spill u. underground release, major m. minor quantity), soil
tYPe (e.g., organic content, previous history of' contamination), and
environmental conditions (e.g., pH, temperature, oxygen content).
Transport processes have been shown to be more significant than
transformation processes in determining the initial fate of petroleum
hydrocarbons released to soil/ground-water systems (1845,1848,1846).
For gasoline released to surface soils or waters, transport to the
atmosphere through volatilization is expected to be the primary fate
pathway; subsequent atmospheric photolysis is expected to be rapid
(1845). Spain & A. (1846) demonstrated that compounds having up to
nine carbons are weathered almost exclusively by evaporation; larger
compounds were weathered primarily by evaporation and biodegradation.
Composition data for gasoline vapor indicate that C,-C, aliphatic
hydrocarbons are rapidly volatilized (2324).
Under conditions of limited volatilization (low temperatures,
subsurface release or concentrated spill) downward migration into the
soil and to the ground water may be important. Several authors
(1811,2243,2252,2329) have reported that oil substances released in
significant quantities to soils result. in a separate organic phase
which moves downward through the unsaturated zone to the less permeable
layer, the soil/ground-water boundary, where they tend to accumulate
and spread horizontally.
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