United States
                             Environmental Protection
                             Agency
                                       Office of Water
                                       4601
                                                    EPA 811-F-95-004i-T
                                                          October 1995
   &EPA
               National Primary Drinking
              Water Regulations
              cis- and trans-1,2-Dichloroethy lene
  CHEMICAL/ PHYSICAL PROPERTIES
  CAS NUMBER:
as-156-59-2
TRANS- 156-60-5
  COLOR/ FORM/ODOR:
    Colorless, odorless liquid

  M.P.: cis- -80 C; trans- -50 C

  B.P.: cis- 60.3 C; trans- 48 C

  VAPOR PRESSURE:
    cis- 273 mm Hg at 30 C;
    trans- 395 mm Hg at 30 C

  OCTANOL/WATER PARTITION (Kow):
    Log Kow = cis-1.86; TRANS- 2.06
          DENSITY/SPEC. GRAV.:
            cis-1.26 at 20" C
            trans-1.28 at 20 C

          SOLUBIUTY: Soluble in water
            cis- 3.5 g/L of water
            trans- 6.3 g/L of water at 25 C

          SOIL SORPTION COEFFICIENT:
            Kocs of cis and trans isomers are
            estimated at 36 to 49; high to very
            high mobility in soil

          ODOR/TASTE THRESHOLDS:  N/A

          HENRY'S LAW COEFFICIENT:
            cis- 0.00337 atm-cu m/mole;
            trans- 0.00672 atm-cu m/mole
               BlOCONCENTRATION FACTOR:
                 BCFs of cis and trans isomers are
                 estimated at 15 to 22; not expected to
                 bioconcentrate in aquatic organisms.

               TRADE NAMES/SYNONYMS:
                 Both isomers-1,2-DCE, Acetylene
                     dichloride;
                 cis- Z-1,2-dichloroethene;
                 trans- E-1,2-dichloroethene,
                     sym-dichloroethylene
DRINKING WATER STANDARDS (IN MG/L)
  MCLG:
  Met:
  HAt(child)-
     1 day:
     Longer:
 CIS

 0.07

 0.07


 4

 3
trans
0.1
0.1


20
2
HEALTH EFFECTS SUMMARY
  Acute: EPA has found  cis- and trans- 1,2-
dichloroethylene to  potentially cause central nervous
system depression from short-term exposures at levels
above the MCL.
  Short-term exposures in  drinking water which are
considered "safe" for a 10-kg (22 Ib.) child consuming 1
liter of water per day:
  cis-  a one-day exposure of 4 mg/L or upto a 7-year
exposure to 3 mg/L.
  trans- a one-day exposure of 20 mg/L or upto a 7-year
exposure to 2 mg/L.
  Chronic:   Both  cis-  and trans-1,2-DCE have the
potential to cause liver, circulatory and nervous system
damage from long-term  exposure at levels above the
MCL. The trans isomer is approximately twice as potent
as the cis- isomer in its ability to depress the central
nervous system.
  Cancer: There is inadequate evidence to state whether
or not either cis- or trans-1,2-DCE have the potential to
cause liver cancer from a lifetime exposure in drinking
water.

USAGE PATTERNS
  Both the cis and trans forms - usually as a mixture - are
used as a solvent for waxes, resins, and acetylcellulose;
in the extraction of rubber; as a refrigerant;  in the manu-
facture of Pharmaceuticals and artificial pearls and in the
extraction of oils and fats from  fish and meat; as a
chemical intermediate for making chlorinated compounds.
  No data were available on recent production levels in
the United States.

RELEASE PATTERNS
  Releases to the environment are expected to be lim-
ited to manufacturing plants in the Gulf Region of the
United States. Since cis-and trans-1,2-DCE are not listed
chemicals in the Toxics Release Inventory, data on
releases during manufacture and  handling are not avail-
able.
  Trans-1,2-dichloroethylene may be released  to the
environment in air emissions and wastewater during its
October 1995
                           Technical Version

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 production and use as a solvent and extractant, in or-
 ganic synthesis, and  in the manufacture of perfumes,
 lacquers, and thermoplastics.
   An  assessment  of the sources  of  trans-1,2-
 dichloroethylene is complicated by the fact that it is a
 priority pollutant while the  cis isomer  is not and the
 standard EPA methods of  analysis do not allow the
 isomers to differentiated. This has resulted in monitoring
 reports erroneously listing the trans isomer when the cis
 isomer is present. The Michigan Department of Health
 has the capability of distinguishing these isomers and
 claims  that it frequently finds the cis isomer  and,  if
 concentrations are high, they occasionally find traces of
 the trans isomer.
ENVIRONMENTAL FATE
   Both the cis- and trans-1,2-dichloroethylenes may be
released to the environment in air emissions and waste-
water during its production and use.  Under anaerobic
conditions that may exist in landfills,  aquifers,  or sedi-
m nt one is likely to find  1,2-dichloroethylenes  that are
formed as breakdown products  from the  reductive
dehalogenation of common industrial solvents trichloro-
ethylene, tetrachloroethylene, and 1,1,2,2-tetrachloro-
ethane.
   The cis-1,2-dichloroethylene is apparently the more
common isomer found although it is mistakenly reported
as the trans  isomer. The trans-isomer, being a priority
pollutant, is more commonly analyzed for and the analyti-
cal procedures generally used do not distinguish  be-
tween isomers.
   If 1,2-dichloroethylenes are released on soil, it should
evaporate and leach into the groundwater where very
slow biodegradation should occur.
   If released into water, 1,2-dichloroethylenes will be lost
mainly through volatilization.
   In the atmosphere, 1,2-dichloroethylenes will be  lost
by reaction with photochemically produced hydroxyl radi-
cals and scavenged by rain. Because it is relatively long-
lived in the atmosphere,  considerable dispersal from
source areas should occur.
   Biodegradation, adsorption to sediment, and biocon-
centration in aquatic organisms should not be significant.
         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. rf 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


         * 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
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