| Chemical Abstract Number (CAS #) |
118741
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| Synonyms | Hexachlorobenzene |
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HCB | Benzene, hexachloro- |
| Analytical Methods |
EPA Method 505 |
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EPA Method 508 |
EPA Method 525 |
EPA Method 612 |
EPA Method 625 |
EPA Method 8081 |
EPA Method 8120A |
EPA Method 8250A |
| Molecular Formula | C6Cl6 |
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| Use | IN ORGANIC SYNTHESES
AS A RAW MATERIAL FOR SYNTHETIC RUBBER; PLASTICIZER FOR POLYVINYL
CHLORIDE; AS A RUBBER PEPTIZING AGENT IN THE MANUFACTURE OF NITROSO
AND STYRENE-TYPE RUBBERS
ADDITIVE FOR PYROTECHNIC COMPOSITIONS FOR THE MILITARY, POROSITY
CONTROLLER IN MANUFACTURE OF ELECTRODES; INTERMEDIATE IN DYE
MANUFACTURE.
A SELECTIVE FUNGICIDE SUGGESTED FOR SEED TREATMENT OF WHEAT
AGAINST BUNT (TILLETIA TRITICI) FOUND EFFECTIVE FOR CONTROL OF
DWARF BUNT. ATTRIBUTE CONTROL TO INHIBITORY ACTION OF VAPOR ON
SPORE GERMINATION.
FUNGICIDE FOR CONTROL OF SMUT ON GRAIN, ESP WHEAT
CHEM INTERMEDIATE. EG, FOR DYES & HEXAFLUOROBENZENE
Manufacture of pentachlorophenol, wood preservative; used in the production of aromatic
fluorocarbons; used to impregnate paper
Fungicide on sunflowers (seed treatment), seedborne diseases, insects; safflower (seed
treatment), seed and seedling diseases, and wireworms.
In Europe, hexachlorobenzene has been used as the precursor for pentachlorophenol, though not
in the USA. European pentachlorophenol made using alkaline hydrolysis of hexachlorobenzene
has more polychlorinated dibenzo-p-dioxin and dibenzofuran impurities than the USA
pentachlorophenol product.
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| Apparent Color | NEEDLES FROM BENZENE-ALCOHOL; White needles
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| Boiling Point | 323-326 DEG C
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| Melting Point | 231 DEG C
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| Molecular Weight | 284.80
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| Density | 1.5691 at 23.6 deg C
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| Environmental Impact | Hexachlorobenzene (HCB) is formed as a waste product in the production of several
chlorinated hydrocarbons and is a contaminant in some pesticides. It may enter the environment in
air emissions and waste water in connection with the above and in flue gases and fly ash from
waste incineration. Non-point source dispersal of hexachlorobenzene results from its presence as a
contaminant in pesticides. 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 colum to sediment and suspended matter. Volatilization from the water
column is rapid; however, the strong adsorption to sediment can result in long periods of
persistence. If released to soil, HCB will be strongly adsorbed and not generally susceptible to
leaching. Hexachlorobenzene will bioconcentrate in fish and enter into the food chain (has been
detected in food during market basket surveys). Human exposure will be from ambient air,
contaminated drinking water and food, as well as contact with contaminated soil or occupational
atmospheres.
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| Environmental Fate | TERRESTRIAL FATE: HCB released to soil is likely to remain there for extended
periods of time due to its strong adsorption to soil (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(1,SRC).
AQUATIC FATE: HCB released to water will evaporate rapidly (half-life of ca 8 hrs has been
measured in the laboratory, adsorb to sediments and bioconcentrate in fish and other aquatic
organisms. Hydrolysis and biodegradation will not be significant processes in water .
ATMOSPHERIC FATE: HCB released to the atmosphere can exist in both the vapor phase and
adsorbed-phase; however, monitoring studies have demonstrated that the vapor phase should
strongly dominate . Degradation of HCB in the atmosphere appears to be extremely slow
(estimated half-life with hydroxyl radicals is 2 years). Long range global transport is possbile and
has been observed . Physical removal of HCB from the atmosphere to aquatic and soil
environments is possible via washout by rainfall and by dry deposition.
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| Drinking Water Impact | DRINKING WATER: 3 cities - Canada 0.06-0.2 parts per trillion, mean 0.1 parts per
trillion .
SURFACE WATER: Niagara Falls dumpsite-water and sediment draining into Niagara River
8-30 ppm ; Great Lakes 0.02-0.1 parts per trillion ; Lake Erie 4 of 5 sites pos, 0-0.04 parts
per trillion ; USA industrialized river avg .
SEAWATER: Mediterranean Sea coastal water Italy 16% pos 0.002 to 0.01 ppb .
RAINWATER: Great Lakes 1-4 parts per trillion , North Pacific - 0.03 parts per trillion ,
Lakes Superior 2.8 parts per trillion .
Southern North Sea: 0.002-0.02 ng/l in solution and 0.01-6.0 ng/g in suspended particles .
Mediterranean Sea near Egypt (1982-3): 0.1-12.6 ng/l .
EFFL: Wastewater effluent - nonferrous metals manufacturing 26 samples, 2 pos 220 ppb
max . Wastewater from four Canadian plants - 1-2 ppt, 1.5 ppt mean . Geismar, LA - pond
and ditch water on an industrial site - 170-75,000 ppb .
Hexachlorobenzene has been detected in fly ash and effluenet gases released from municipal
refuse incinerators and other combustion facilities-levels in flue gas ranged from 9.5 ng/cu m to 11
ug/cu m(1,2,3,4).
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