United States
                           Environmental Protection
                           Agency
                    Office of Water
                    4601
            EPA 811-F-95-004m-T
                 October 1995
                            National  Primary Drinking
                           Water  Regulations
                            Ethylbenzene
  CHEMICAL/ PHYSICAL PROPERTIES

  CAS NUMBER:  100-41-4

  COLOR/ FORM/ODOR:
    Colorless liquid with a sweet, gasoline-
    like odor

  M.P.: -95 C    B.P.: 136.2C

  VAPOR PRESSURE:  10 mm Hg at 25.9 C

  DENSITY/SPEC. GRAV.: 0.87 at 20" C
OCTANOL/WATER PARTITION (Kow):
  Log Kow = 3.15

SOLUBILITY: 0.14 g/L of water at 15 C;
  low solubility in water

SOIL SORPTION COEFFICIENT:
  Koc measured at 164 silt loam;
  moderate mobility in soil

ODOR/TASTE THRESHOLDS:   Taste and
  odor threshold in water is 0.029 mg/L
BlOCONCENTRATION FACTOR:
  Measured log BCF values of 0.67 to 1.9
  in fish; not expected to bioconcentrate
  in aquatic organisms.

HENRY'S LAW COEFFICIENT:
  0.0084 atm-cu m/mole; rapid evappra-
  tion from water

TRADE NAMES/SYNONYMS:
  Ethylbenzol, Phenylethane
DRINKING WATER STANDARDS
  MCLG:     0.7 mg/L
  Met:      0.7 mg/L
  HAL(child):  1 day: 30 mg/L
            10-day: 3 mg/L

HEALTH EFFECTS SUMMARY
               RELEASE PATTERNS
                Ethylbenzene will enter the atmosphere primarily from
               fugitive emissions and exhaust connected with its use in
               gasoline. More localized sources will be emissions, waste
               water and spills from its production and industrial use.
                From 1987 to 1993, according to EPA's Toxic Chemi-
               cal Release Inventory, ethylbenzene releases to water
               totalled over 47,293 IDS., while releases to land totalled
Acute: EPA has found ethylbenzene to potentially
cause drowsiness, fatigue, headache and mild eye and
respiratory irritation from short-term exposures at levels
above the MCL.
Drinking water levels which are considered "safe" for
short-term exposures: For a 10-kg (22 Ib.) child consum-
ing 1 liter of water per day: a one-day exposure to 30 mg/
L; a ten-day exposure to 3 mg/L.
Chronic: Ethylbenzene has the potential to cause
damage to the liver, kidneys, central nervous system and
eyes from long-term exposure at levels above the MCL.
Cancer: There is inadequate evidence to state whether
or not ethylbenzene has the potential to cause cancer
from a lifetime exposure in drinking water.

USAGE PATTERNS

Production of ethylbenzene has increased: from 6.9
billion Ibs. in 1 982 to 11 .8 billion Ibs in 1 993. The greatest
use - over 99 percent - of ethylbenzene is as an interme-
Jiate for styrene monomer production.
Other use's include: a solvent for coatings, and in the
production of synthetic rubber and cellulose acetate.
Toxic RELEASE INVENTORY -
RELEASES TO WATER AND LAND: 1987
Water
TOTALS (in pounds) 47,293

Top Ten States
TX 9,870
VI 1,233
IL 31
PR 0
VA 17,997
DE 3,460
NJ 1 ,892
NM 0
WY . 250
LA 4,383

Major Industries
Petroleum refining 55,201
Plastics, resins 12,384
Indust. Organics 10,683
Pharmaceuticals 14,090
Metal containers 0


TO 1993
Land
714,580

480,164
72,245
44,789
23,980
1,950
13,324
11,510
13,076
12,755
4,552


718,884
9,212
9,781
0
11,510

* Water/Land totals only include facilities with releases
greater than a certain amount - usually 1000 to 10,000 Ibs.
October 1995
        Technical Version

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over 714,000 Ibs. These releases were primarily from
petroleum refining industries. The largest releases oc-
curred in Texas. The largest direct releases to water
occurred in Virginia.
ENVIRONMENTAL FATE
   If ethylbenzene is released to the atmosphere, it will
exist  predominantly in the vapor phase, based on its
vapor pressure. There it will photochemically degrade by
reaction with hydroxyl radicals (half-life 0.5 to 2 days) and
partially return to earth in rain. It will not be subject to
direct photolysis.
   Evaporation and biodegradation are significant in wa-
ter. Ethylbenzene will evaporate rapidly from water: a
half-life for evaporation from moving, shallow water is 3.1
hr. After a period of inocula adaptation, ethylbenzene is
biodegraded fairly rapidly by sewage or activated sludge
inoculua.  As a component of gas  oil, it is completely
degraded in groundwater in 8 days and seawater in 10
days. No degradation was observed in anaerobic reac-
tors or at low concentrations in  batch reactors under
denitrifying  conditions. Ethylbenzene is resistant to hy-
drolysis. Some ethylbenzene may be adsorbed by sedi-
ment.
   Ethylbenzene is only adsorbed moderately by soil. The
measured Koc for silt loam was 164. Its presence in bank
infiltrated water suggests that there is a good probability
of its  leaching through soil.  It  will not significantly hydro-
lyze in water or spil.
   Significant bioconcentration in fish is not expected to
occur. Experimental data  on the  bioconcentration of
ethylbenzene include a log BCF of 1.9 in goldfish and
0.67 for clams exposed to the water-soluble fraction of
crude oil. This, with a calculated log BCF of 2.16 in fish,
indicate that ethylbenzene should not significantly biocon-
centrate in aquatic organisms.
   The primary source of exposure is from the air espe-
cially  in areas of high traffic. However, ethylbenzene is a
contaminant in many drinking water supplies and levels
can be quite high for wells near leaking gasoline storage
tanks and for many drinking waters taken from surface
waters.
         OTHER REGULATORY INFORMATION
         MONITORING:
         FOR GROUND/SURFACE WATER SOURCES:
           INITIAL FREQUENCY-  4 quarterly samples every 3 years
           REPEAT FREQUENCY- Annually after 1 year of no detection
         TRIGGERS - Return to Initial Freq. if detect at > 0.0005 mg/L
         ANALYSIS:
         REFERENCE SOURCE
         EPA 600/4-88-039
METHOD NUMBERS
502.2; 524.2
         TREATMENT:
         BEST AVAILABLE TECHNOLOGIES
         Granular Activated Charcoal and Packed Tower Aeration


         FOR ADDITIONAL INFORMATION:
         4 EPA can provide further regulatory and other general information:
          EPA Safe Drinking Water Hotline - 800/426-4791


         4 Other sources of toxicological and environmental fate data include:
          Toxic Substance Control Act Information Line - 202/554-1404
          Toxics Release Inventory, National Library of Medicine - 301/496-6531
          Agency for Toxic Substances and Disease Registry - 404/639-6000
October 1995
Technical Version
                    Page 2

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