health and safety plan solid waste management unit assessment

JP-4 (JET FUEL 4) 64-15
Compared with the marine environment, infiltration into porous
soils slows the evaporative loss of volatile hydrocarbons. McGill &,
4. (2267) concluded that up to 20-40% of crude oils may volatilize
from soils; elevated temperatures, lateral spreading and adsorption
onto surface vegetation may facilitate evaporation at such levels.
Volatilization of JP-4 components is expected to be more extensive than
volatilization of crude oils. Purging of the water soluble fraction of
JP-4 fuel with nitrogen and air demonstrated a rapid loss of JP-4
hydrocarbons (80% loss in 2 minutes) (2250).
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) 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. The organic layer floats on the ground water
and is carried in the general direction of ground water flow. At the
oil-water interface, some hydrocarbons are leached according to their
aqueous solubility. The pattern of migration of the hydrocarbon phase
may be very different from that of the ground water. Due to fluctuations
in ground-water elevation, over time the organic layer on top of
the aquifer may be transported into several zones where the components
occur in the gaseous phase (able to diffuse in all directions, including
upward), liquid phase (adsorbed onto rock particles or sealed
under water) or dissolved/emulsified in water (1811).
Migration through soils may be retarded to some extent by sorption.
In general, sorption of aviation kerosene on soils has been
reported to be weak. Migration is expected to be fastest through
previously contaminated soils where, the sorptive sites may be unavailable;
on the other hand, soil-water content increases sorption and
slows migration of JP-4 hydrocarbons. Sorption may also alter the
availability of hydrocarbons for biodegradation and other weathering
processes (1846,1811,2248).
In fissured rock the migration of JP-4 hydrocarbons is much less
uniform than in porous soils. Preferential spreading through crevices,
sometimes changed the direction of flow, may occur. Determination of
the potential ground-water contamination in fissures rock is thus very
difficult (1811).
Sediment-water sorption studies (2248) were performed on jet fuel
dissolved in water: 3 sediments and 3 clays were utilized. The
observed adsorption constants were small compared to those of other
non-polar organics. For the individual JP-4 components the magnitude
of the adsorption constant is dependent on the size and complexity of
the hydrocarbon, and bears an inverse relationship to its aqueous
solubility. The nature of adsorbent was important (non-swelling clays
were reported to be poor adsorbents compared to sediments) but the
organic carbon content exhibited only a casual relationship to
6/87