(VCCEP) Tier 1 Pilot Submission for BENZENE - Tera

Table 5.3: Environmental Fate and Transport Characteristics of Benzene
Characteristic Description* Reason
Volatility High High vapor pressure of 95 mm Hg @
25°C.
Water Solubility Lowmoderate
Propensity of benzene to
partition to the atmosphere
from surface water
Benzene VCCEP Submission
March 2006
Moderatehigh
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Slight solubility of 1,791 mg/l @ 25°C.
High Henry’s Law constant of
5.5 x 10 -3 atm-m 3 /mol.
Groundwater mobility High Low Log Koc of 1.8 to 1.9.
Fraction of human exposure
that occurs via the inhalation
pathway
Biodegradation potential of
benzene in groundwater
Residence time of benzene in
the atmosphere
Propensity of benzene to
bioaccumulate in marine
organisms
Bioconcentration potential of
benzene in plants
Fraction of benzene released
to the environment that
partitions into the air
High (99%) High fraction of benzene that
partitions to the air (ATSDR 1997).
Moderate Benzene biodegradation in
groundwater function of presence of
acclimated microorganisms and
available electron acceptors or level of
methanogenesis activity.
Low-
Moderate
(half life of
less than
two weeks)
Rapid chemical degradation reactions
with hydroxyl radicals (ATSDR 1997).
Low Low log Kow of 2.13 (ATSDR 1997).
Low Low amount of root uptake since most
benzene is found in the vapor phase;
limited amount of air-to-leaf transfer
can occur in some plants (ATSDR
1997).
High
(99.9%)
High volatility and Henry’s Law
Constant; Low water solubility.
* The descriptions are based on the rankings reflective of those generally accepted in
the scientific literature.
5.4 Pure Benzene Production
Pure benzene is isolated primarily for use as an intermediate feedstock in the production of
other chemicals such as ethylbenzene. Benzene is produced by the petroleum industry and to
a lesser degree, by the steel industry as a byproduct of coke production (Table 5.4). The major
chemical processes used in benzene production include catalytic reforming [naphthene