health and safety plan solid waste management unit assessment

AUTOMOTIVE GASOLINE 65-19
components (e.g., naphthalene and methylnaphthalene) by fish and domestic
animals, which may also result in human exposures due to the
bioconcentration of these components.
Ground water contaminated with gasoline can lead to inhalation
exposures in homes using this water. In one study of homes in Mine
(2313), concentrations of total benzene, toluene and xylene measured in
air of the closed bathrooms while hot showers were running were 2.05,
3.15, and 30 ppm in homes with 6, 3, and 20 ppm, respectively, of total
hydrocarbons in their water. In the two homes with the highest total
concentrations, xylene accounted for roughly 63% of the concentration
in air, toluene 29-32% and benzene .5-g%; in the other home 95% was
benzene, the rest toluene. The author of this study suggested that
odor may be a sensitive indicator of gasoline contamination in water.
In the houses with high hydrocarbon contamination, an offensive odor
was noticeable, especially during sampling (2313). Even though no
benzene, toluene or xylene was detected in the air of three homes with
less than 0.5 ppm total hydrocarbons in their water, in two of these
homes gasoline odors were present in the' bathroom. However, a
modelling study (2314) indicates that petroleum-based pollutants
(benzene, toluene, xylene) present in water at 5 to 50 ppb--levels
below detectable taste or odor threshholds--may result in peak air
concentrations that cause mucous membrane irritation.
Volatilization of gasoline hydrocarbons in soil is another
potential source of human exposure. This exposure pathway is likely to
be more significant for gasoline than other petroleum products because
of its high volatility. Exposures may be more intensive when the soil
is contaminated directly from leaking underground storage tanks and
pipes, rather than from surface spills. In such cases, the more
volatile components do not have an opportunity to evaporate before
penetrating the soil. Once in the soil, the hydrocarbons evaporate
saturating the air in the soil pores, and diffusing in all directions
including upward to the soil surface. The vapors may diffuse into the
basement of homes or other structures in the area resulting in
inhalation exposures to the building's occupants.
65.2.4 Other Sources of Human Exposure
Data on ambient concentrations of gasoline in air and water as
well as food and drinking water are not readily available in the
literature. Exposure information on specific components may be found
in other chapters of the IRP Toxicology Guide.
The volatile nature of automotive gasoline suggests that
inhalation may represent a significant exposure pathway. The average
concentrations of automotive gasoline to which residents of communities
near bulk terminals, bulk plants, and service stations (employing no
special controls) are exposed have been estimated as 1.41, 0.073, 0.026
ppm, respectively (2311). It should be emphasized that these valuesare
averaged over a lifetime and in all cases the concentrations are
estimated from emission rates. Exposure to service station employees
and individuals filling their tanks at self-service operations are muoh
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