United States
Environmental Protection
Agency
Office of Water
4601
EPA811-F-95-003S-T
October 1995
National Primary Drinking
Water Regulations
Hexachlorobenzene
CHEMICAL/ PHYSICAL PROPERTIES
CAS NUMBER: 118-74-1
COLOR/ FORM/ODOR:
White needles
M.P.: 231° C B.P.: 323-326° C
VAPOR PRESSURE: 1.09x10"5 mm Hg, 25° C
OCTANOL/WATER PARTITION (Kow):
Log Kow = 5.31 , .
DENSITY/SPEC. GRAV.: 1.57 at 23.6" C
SOLUBILITY: 0.035 mg/L of water; In-
soluble in water
SOIL SORPTION COEFFICIENT:
Koc estimated at 4-5; low soil mobility
ODOR/TASTE THRESHOLDS: N/A
BlOCONCENTRATlON FACTOR:
Log BCF=3.1 to 4.5 in fish; expected
to bioconcentrate in aquatic organ-
isms.
HENRY'S LAW COEFFICIENT:
0.03 to 0.07 atm-cu m/mole; rapid
evaporation from water
TRADE NAMES/SYNONYMS:
Hexa CB, HCB, Phenyl perchloryl,
Perchlorobenzene, Pentachlorophenyl
chloride, Anticarie, Bunt-cure, Co-op
hexa, Julin's carbon chloride, No bunt
40, No bunt 80, Sanocide, Snieciotox,
Smut-go, Granox hm, Voronit C
DRINKING WATER STANDARDS
MCLG: zero mg/L
MCL: 0.001 mg/L
HAL(child): 1 day: 0.05 mg/L
Longer-term: 0.05 mg/L
WEALTH EFFECTS SUMMARY
Acute: EPA has found hexachlorobenzene (HCB) to
potentially cause the following health effects from acute
exposures at levels above the MCL: skin lesions, nerve
and liver damage
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, upto a 7-year exposure to 0.05
mg/L.
Chronic: HCB has the potential to cause the following
health effects from long-term exposures at levels above
the MCL: damage to liverand kidney tissue; reproductive
effects; benign tumors of endocrine glands.
Cancer: There is some evidence that HCB may have
the potential to cause cancer from a lifetime exposure at
levels above the MCL.
USAGE PATTERNS
HCB is produced as a by-product or waste material in
the production of tetrachloroethylene, trichloroethylene,
carbon tetrachloride, chlorine, dimethyl
iretrachloroterephthalate, vinyl chloride, atrazine,
propazine, simazine, pentachloronitrobenzene, and
mirex. It is a contaminant in several pesticides including
dimethyl tetrachlorophthalate and pentachloronitroben-
zene.
Production data on hexachlorobenzene is limited. In
1982, imports were reported to be 38,000 IDS, with no
evidence of commercial domestic production. However,
2 to 5 million Ibs may be generated each year as a waste
by-product of chlorination processes in chemical manu-
facture.
The greatest use of HCB is in making other organic
compounds such as rubber, dyes, wood preservatives.
Other uses of include: an additive in explosives, in
electrode manufacture, and as a fungicide on grains,
especially wheat.
RELEASE PATTERNS
Major environmental releases of HCB are due to air
Toxic RELEASE INVENTORY -
RELEASES TO WATER AND LAND:
1987 TO 1993
TOTALS (in pounds)
Top States
LA
TX
Major Industries
Alkalies, chlorine
Agricultural chemicals
Water
1,286
677
609
854
297
Land
1
1
0
1
0
October 1995
Technical Version
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and water discharges from its production as a by-product
of chemical manufacture, or from pesticide applications.
It is also released by some waste incineration processes.
It has been detected in treated waste water from non-
ferrous metal manufacturing.
From 1987 to 1993, according to EPA's Toxic Chemi-
cal Release Inventory, HCB releases to land and water
totalled 1,287 IDS., all of which was to water. These
releases were primarily from alkali, chlorine and agricul-
tural chemical industries. The largest releases occurred
in Louisiana and Texas.
ENVIRONMENTAL FATE
HCB is a very persistent environmental chemical due
to its chemical stability and resistance to biodegradation.
If released to the atmosphere, HCB will exist primarily
in the vapor phase and degradation will be extremely
slow (estimated half-life with hydroxyl radicals is 2 years).
Long range global transport is possible. Physical removal
from the atmosphere can occur via washout by rainfall
and dry deposition.
If released to water, HCB will significantly partition from
the water column to sediment and suspended matter.
Volatilization from the water column is rapid (half-life of
about 8 hrs has been measured in the laboratory);
however, the strong adsorption to sediment can result in
long periods of persistence. Hydrolysis and biodegrada-
tion will not be significant processes in water.
If released to soil, HCB will be strongly adsorbed and
not generally susceptible to leaching (a half-life of 1530
days has been reported). Little biodegradation will occur
and transport to groundwater is expected to be slow,
depending upon the organic carbon content of the soil;
some evaporation from surface soil to air may occur, the
extent of which is dependent upon the organic content of
the soil.
Hexachlorobenzene will bioconcentrate in fish and
enter into the food chain (has been detected in food
during market basket surveys). Log BCF in trout, 3.7-4.3;
sunfish, 3.1-4.3; and fathead minnow, 4.2-4.5. Similar
high BCF values (log BCF 2-3) have been measured in
aquatic microcosms.
Human exposure will be from ambient air, contami-
nated drinking water and food, as well as contact with
contaminated soil or occupational atmospheres.
OTHER REGULATORY INFORMATION
MONITORING:
FOR GROUND/SURFACE WATER SOURCES:
INITIAL FREQUENCY- 4 quarterly samples every 3 years
REPEAT FREQUENCY- If no detections during initial round:
2 quarterly per year if serving >3300 persons;
1 sample per 3 years for smaller systems
TRIGGERS - Return to Initial Freq. if detect at > 0.0001 mg/L
METHOD NUMBERS
505:508:508.1:525.2
ANALYSIS:
REFERENCE SOURCE
EPA 600/4-88-039
TREATMENT:
BEST AVAILABLE TECHNOLOGIES
Granular Activated Charcoal
FOR ADDITIONAL INFORMATION:
* EPA can provide further regulatory and other general information:
• EPA Safe Drinking Water Hotline - 800/426-4791
4 Other sources of lexicological 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
• National Pesticide Hotline - 800/858-7378
October 1995
Technical Version
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