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

  CAS NUMBER: 106-46-7

  COLOR/ FORM/ODOR: White crystals with
    distinctive aromatic, mothball-like odor

  M.P.:53.1C   B.P.: 174 C

  VAPOR PRESSURE: 10 mm Hg at 54.8 C

  OCTANOL/WATER PARTITION (Kow):
    Log Kow = 3.37
DENSITY/SPEC. GRAV.: 1.25 g/ml at 20 C

SOLUBILITIES: 65.3 mg/L of water at 25 C

SOIL SORPTION COEFFICIENT:
   Koc estimates range from 409 TO
   1514

ODOR/TASTE THRESHOLDS:  N/A

BlOCONCENTRATION FACTOR (BCF):
   Low; Ranges from 100 to 250 in
   various species
HENRY'S LAW COEFFICIENT:
  0.0015 atm-cu m/mole at 20 C

TRADE NAMES/SYNONYMS: Paradichloroben-
  zene; Paradichlorobenzol; Paramoth;
  Di-Chloricide; Paradi; Paradow; Persia-
  Perazol; Evola; Parazene
DRINKING WATER STANDARDS
  MCLG:      0.075 mg/L
  MCL:       0.075 mg/L
  HAL(child):  1 day: 10 mg/L
             Longer-term: 10 mg/L

HEALTH EFFECTS SUMMARY
  Acute: May cause nausea, vomiting, headaches, and
irritation of the eyes and respiratory tract.
  Drinking water levels which are considered "safe" for
short-term exposures: Fora 10-kg (22 Ib.) child consum-
ing 1 liter of water per day: upto a 7-year exposure to 10
mg/L.
  Chronic:   p-DCB has the potential to  cause  the
following  health effects from long-term exposures at
levels above the  MCL: anemia,  skin lesions, appetite
loss, yellow  atrophy of the liver and  adverse blood
effects.
  Cancer: There is some evidence that p-DCB has the
potential to cause cancer from a lifetime exposure at
levels above the MCL.

USAGE PATTERNS
  Available production data on p-DCB shows a decreas-
ing  trend down to 15 million Ibs. in 1981. Demand
 owever, was at 74 million Ibs in 1986; rose to 77 million
,os.  the following  year, and was projected to continue
increasing.
  p-Dichlorobenzene is used as an insecticidal fumigant
               against clothes moths (35-40%); as a deodorant for
               garbage and restrooms (35-40%); as an insecticide for
               control of fruit borers and ants; may be applied to tobacco
               seed beds for blue mold control; for the control of peach
               tree borer; and mildew and mold on leather and fabrics.
                 It is also used as an intermediate in the manufacture of
               other organic chemicals such as 2,5-dichloroaniline, and
               in plastics, dyes, Pharmaceuticals.

               RELEASE PATTERNS
                 Chemical waste dump leachates and direct manufac-
               turing effluents are reported to be the major source of
                 Toxic RELEASE INVENTORY -
                 RELEASES TO WATER AND LAND:
              1987 TO 1993
                 TOTALS (in pounds)

                 Top Five States*
                 VW
                 TX
                 DE
                 GA
                 LA
      Water
      *
      33,675
      27,676
       1,280
       1,870
        750
        503
                 Major Industries
                 Alkalies, chlorine       27,676
                 Industrial org. chem.      3,076
                 Agricultural chem.         750
                 Cyclic crudes, intermed.    600
Land

4,482
   0
3,132
  200
   0
   0
                          0
                       3,350
                          0
                          0
                 * Water/Land totals only include facilities with releases
                 greater than a certain amount - usually 1000 to 10,000 Ibs.
October 7995
         Technical Version

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 pollution of the chlorobenzenes (including the dichloro-
 benzenes) to Lake Ontario.  The  major source of p-
 dichlorobenzene emission to the atmosphere is volatil-
 ization from use in toilet bowl deodorants, garbage de-
 odorants and moth flakes.
   In 1972, 70-90% of the annual USA production of p-
 dichlorobenzene was estimated to have been released
 into the atmosphere primarily as a result of use in toilet
 bowl and garbage deodorants and use in moth control as
 a fumigant.
   In 1984 it was reported that 67% of the p-dichloroben-
 zene consumed in the USA is used for space deodorants
 and moth control with 33% used as an intermediate for
 polyphenylene sulfide resin production; volatilization from
 the deodorants and moth flakes will therefore be the
 major emission source to the atmosphere.
   From 1987 to 1993, according to the  Toxic Release
 Inventory, p-DCB releases to water totalled almost 34,000
 Ibs. Releases to, land totalled nearly 4,500  Ibs. These
 releases were primarily from a single chemical manufac-
 turing plant in West Virginia.
       benzene in rain-water suggests that atmospheric wash-
       out is possible.
         For the most part, experimental BCF values reported
       in the literature are less than 1000 which suggests that
       significant bioconcentration will not occur; however, a
       BCF of 1800 was determined for guppies in one study.
         General population  exposure to p-dichlorobenzene
       may occur through oral consumption of contaminated
       drinking water and food (particularly fish) and through
       inhalation of contaminated air.
ENVIRONMENTAL FATE
  If released to soil, p-dichlorobenzene can be moder-
ately to tightly adsorbed. Leaching from hazardous waste
disposal areas  has occurred and  the detection of p-
dichlorobenzene in various groundwaters indicates that
leaching can occur. Volatilization from soil surfaces may
be an important transport mechanism. It is possible that
p-dichlorobenzene will be slowly biodegraded  in soil
under  aerobic conditions. Chemical transformation  by
hydrolysis, oxidation or direct photolysis  are not ex-
pected to occur in soil.
  If released to water, volatilization may be the dominant
removal process. The volatilization half-life from a model
river one meter deep flowing one meter/sec with a wind
velocity of 3 m/sec is estimated to be 4.3 hours at 20 deg
C. Adsorption  to sediment will be a major environmental
fate process based upon extensive monitoring data in the
Great Lakes area and Koc values based upon monitoring
samples. Analysis of Lake Ontario sediment cores has
indicated  the  presence and  persistence of p-dichloro-
benzene since before 1940. Adsorption to sediment will
attenuate volatilization. Aerobic biodegradation in water
may be possible, however, anaerobic biodegradation is
not expected to  occur.
  Aquatic hydrolysis, oxidation and direct photolysis are
not expected to be important. If released to air, p-dichlo-
robenzene will exist predominantly in the vapor-phase
and will react  with photochemically produced hydroxyl
radicals at an estimated half-life rate of 31 days in typical
atmosphere. Direct photolysis in the troposphere is not
expected to be  important. The detection of p-dichloro-
         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:
         * EPA can provide further regulatory and other general information:
          EPA Safe Drinking Water Hotline - 800/426-4791

         * 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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