530R86104
         ATER     QUALITY
          ADVISORY
                       DCPA
        Criteria  and  Standards  Division

    Df-fice  a -F  Water  Regulations  and  Standards

                   United  States

         EIn v ir anrnen t al  Protection  Rgency
                 MRRCH   1  3 8 G

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                          WATER QUALITY ADVISORY
                               Number   3  .

                                   DCPA

                     Criteria  and Standards  Division
                Office  of  Water Regulations  and Standards
             United  States  Environmental  Protection Agency


      The  advisory concentration for DCPA in ambient water for the
  protection of freshwater aquatic life is estimated to be 14.3 mg/L.  No
saltwater data were reviewed,  and  no advisory  concentration for the
protection of saltwater aquatic  organisms is estimated.  Care should
be taken in the application of this advisory,  with  consideration of
its derivation, as stated in  the attached support document.

    A value given to protect  aquatic life can  be derived from no
observed effect levels (NOEL),  the lowest concentration  found in the
data which has been observed  to  cause  acute or chronic toxicity or
other experimental data which may  be applicable. When there is no
valid experimental evidence,  a value may be derived from a model
which uses structure-activity relationships  (SAR) as its basis. The
advisory concentrations should be  used with caution, since they are
derived from minimal experimental  evidence, or in the case of SAR
derived values, no data on  the specific chemical.

    The advisory  concentration for DCPA in ambient  water for the
protection of human health  is estimated to be  0.008 ug/L, based on
data and information which are available  to the U.S. EPA.  Care should
be taken in the application of this advisory,  with  consideration of
its derivation, as stated in  the attached support document.

    An advisory concentration can  be derived from a number of
sources:  The Office of Drinking Water Health  Effects Advisories;
Acceptable Daily  Intake(ADI)  values from EPA;  Office of Pesticides
and Toxic Substances risk assessments;  Carcinogen Assessment Group
(CAG)  cancer risk  estimates; risk estimates derived from the open
literature; or other sources which will be given in the support
document.  The advi-sory concentrations derived from these sources
will vary in confidence and usefulness, based  on the amount and
quality of data used as well  as  the assumptions behind the original
estimates.  The user is advised  to  read the background information
carefully  to determine the strengths or deficiencies of the values
given in the advisory.
                      U.S. Environmental Protection Agency
                      Region 5, Library (PL-12J)
                      77 West Jackson Boulevard, 12th Floor
                      Chicago, IL 60604-3590

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     HUMAN HEALTH AND AQUATIC LIFE
       LITERATURE SEARCH AND DATA
          BASE EVALUATION FOR
                  DCPA
  U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF WATER REGULATION AND STANDARDS
    CRITERIA AND STANDARDS DIVISION
        WASHINGTON, D.C.  20460

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                          TABLE OF CONTENTS
INTRODUCTION  	,
SCOPE OF SEARCH 	
SUMMARY OF FINDINGS 	,
     Aquatic Toxicity 	,
     Health Effects 	,
CRITERIA EVALUATION AND RECOMMENDATIONS
REFERENCES 	
1
1
2
2
5
5
9
                            LIST OF TABLES
Table I.  Summary of Aquatic Toxicity Literature Review of DCPA
Table 2.  Summary of Health Effects Literature Review of DCPA ..
Table 3.  Data Requirements for Calculation of Aquatic Life
          Interim Criteria—DCPA 	
Table 4.  Data Requirements for Calculation of Human
          Interim Criteria—DCPA 	
3
4

7

8

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                    HUMAN HEALTH AND AQUATIC LIFE
                      LITERATURE SEARCH AND DATA
                         BASE EVALUATION FOR
                                 DCPA
                 U.S. ENVIRONMENTAL PROTECTION AGENCY
               OFFICE OF WATER REGULATION AND STANDARDS
                   CRITERIA AND STANDARDS DIVISION
                       WASHINGTON,  D.C.   20460
                             INTRODUCTION


    Dimethyl tetrachloroterephthalate  (DCPA) is a chlorinated benzoic
acid used as a selective pre-emergent herbicide for control of annual
grasses, and certain broadleaf weeds (McEwen and Stephenson, 1979;
WSSA,  1974).   DCPA is used commercially on turf,  ornamentals,
strawberries, soy and field beans, onions, cabbage, and cotton.  The
basic producer of DCPA  is  Diamond  Shamrock,  U.S.A.,  and the most
frequently encountered  common and trade names are Dacthal, DCPA, DAC
893, chlorathal dimethyl,  and Fatal.  DCPA has an estimated half life
of 100 days in most soil types and is either adsorbed to or absorbed
by organic matter  (WSSA,  1979).

    DCPA is an odorless, white crystalline compound with the following
physical and chemical properties:


           Molecular weight             332
           Melting point                156 C
           Vapor pressure               <0.01 mm Hg at 40 C
           Solubility in water at 25 C  0.5 ppm.


    Hexachlorobenzene may  be  a contaminant of DCPA  (8-9 percent).   The
toxicity of hexachlorobenzene may need to be considered for criteria
calculation  (Burns  et al.,  1974).


                           SCOPE OF SEARCH


    Computerized literature searches and printed abstracts of TOXLINE,
TOXBACK, NTIS,  and the Toxicology Data Base were  used as primary

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sources for identifying data on aquatic toxicity  and human health
effects,  focusing primarily on laboratory studies of dose-response of
aquatic organisms and mammalian species.  The quality  assurance/
quality control measures used in these studies were evaluated for
their use of positive and negative controls, replication, and chemical
analysis of test concentrations.

    Additionally, the quality of experimental methods  was evaluated by
comparison to guidelines established by the U.S.   EPA  in "Guidelines
and Methodology Used in Preparation of Health Effect Assessment
Chapters of the Consent Decree Water Quality Criteria  Documents"  (FR
45:79347,  November 28,  1980)  and the "Guidelines  for Deriving
Numerical National Water Quality Criteria for the Protection of
Aquatic Life and Their Uses" (Stephan et al.,  1985).   Data other than
dose-response relationships  (e.g.,  metabolic studies and field obser-
vations) were also collected to provide ancillary information relevant
to aquatic toxicity and human health effects.


                         SUMMARY OF FINDINGS

                           Aquatic Toxicity


    Few data are available  concerning  the toxicity of  DCPA to aquatic
life  (Table 1).   In general, the herbicide  is reported to be of low
toxicity to these  species tested  (WSSA, 1979).

    An LC50 (estimated concentration at which  50  percent of  the test
animals die) of DCPA for Tubifex tubifex,  an aquatic oligochaete worm,
was reported at 286 ppm,  indicating low toxicity  (Voronkin  and
Loshakov, 1973).   However, DCPA inhibited the activity of the enzyme
succinate dehydrogenase in these worms.

    Only one study was found that reported the toxicity of DCPA to
fish  (>500 ppm);  however,  neither the species tested nor the original
study was cited  (WSSA, 1979).

    Miller  and Gomes  (1974) collected  five species of  fish  from the
lower Rio Grande River Valley,  Texas, and analyzed them for tissue
residues of DCPA.  The herbicide was used  in this region for weed
control in onions and cotton.  From this study, a bioconcentration
factor was estimated for menhaden (Brevoortia tyrannus) by averaging
the mean waterborne and fish residue levels of DCPA per month for a 2-
year period (Table  1).   These data indicate that  DCPA  concentrates
significantly in  fish  (about 3,000 times the concentration  of the
surrounding water).

    DCPA residues in fish tissues from waters  averaging 0.5  ppb DCPA
concentration showed maximum concentrations ranging from 132 ppb in
testes to 555 ppb in liver  (Table  1).

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                            Health Effects


    The toxicity of DCPA to mammals appears to be relatively low, with
LD50 (estimated dosage at  which  50 percent mortality occurs) values
ranging from 320 mg/kg for mice to 3,000 mg/kg for rats (Table 2).
Additionally,  a no-observed-effect level  (NOEL) of 10,000  ppm  in diet
was found for dogs and rabbits fed DCPA for  a 2-year period.   A
probable oral  lethal  dose of  500-5,000 mg/kg was reported  for  humans
(CTCP,  1976).   Cytogenetic toxicity of DCPA  is indicated by an
increase in the number of  metaphase stages with multiple aberrations
in bone marrow cells of mice  (Kurinnyi et  al.,  1982).   All literature
sources from which health effects data were  collected  either cited
results from other studies (WSSA,  1979) or did not document methods
adequately (Kurinnyi et al.,  1982).  Thus,  these data were difficult
to evaluate with respect to  quality assurance,  quality control, and
other parameters.

    DCPA exposures may have  public health  significance because
hexachlorobenzene  (HCB) has  been found to be an important  contaminant
of DCPA.  One study has found that HCB increased the incidence of
hepatomas and hemangioendotheliomas in golden hamsters and mice fed 50
to 200 ppm HCB in diet for durations between 80 weeks  to the entire
life span of the animals  (Cabral et al., 1977 and 1978).   A study of
residues in workers exposed  to DCPA detected no levels of  DCPA in
blood, whereas concentrations of HCB averaged 40 ppb in blood, with a
maximum level  of  310  ppb  (Burns et al., 1974).  Although no adverse
effects were detected in these workers, HCB  may be carcinogenic
(Cabral et al., 1977 and 1978).
               CRITERIA EVALUATION AND RECOMMENDATIONS


    No water-quality criterion for DCPA was found in the  literature
search or in various water quality criteria documents.  The  lack of
adequate data makes recommendation of criteria difficult.  No
verifiable toxicity data were found for aquatic organisms although
there is an indication (see Table 1) that levels as high as  500 ppm
DCPA are not toxic to fish.   Furthermore, the  formulas  stipulated by
the guidelines  (Stephan et al.,  1985)  are not  operable  because of the
lack of data.

    However, because fish can concentrate DCPA at waterborne levels of
0.5 ppb,  bioaccumulation of DCPA in aquatic organisms may pose a
health risk to humans who consume these animals from areas where the
herbicide is used regularly  (Miller and Gomes, 1974).  Consumption of
fish with these levels may result in exposure  to  elevated levels of
DCPA although the toxicity to humans  of DCPA may be quite low (500-
5, 000 mg/kg).

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    The potential for cytogenetic toxicity (mutagenesis)  of DCPA has
been implied (Kurinnyi et al.,  1982); however,  the  methods of these
determinations and the significance of  these  results for  human health
was not reported.   Furthermore,  no appropriate  data were  found
concerning carcinogenicity or long-term effects for mammals.  The
absence of appropriate chronic parameters (i.e., NOAEL, LOEL, LOAEL)
does not allow calculation of a water quality criterion for human
health.

    Potential carcinogenicity of hexachlorbenzene (HCB),  a contaminant
of DCPA, has been reported for hamsters and mice at levels of 50 ppm
during long exposures (Cabral et al.,  1977 and 1978).   Because HCB
comprised 8-9 percent of DCPA used for  weed control in Texas during
the early 1970's (Burns  et al.,  1974),  it may be an important
contaminant of DCPA for human health.  The U.S. EPA (1980) has
established a recommended criteria for HCB of 0.72  ng/L based on a
cancer risk of 10~6 for a lifetime exposure.  This  should be taken
into account if HCB contamination is suspected.

    In summary,  no adequate data were  found for any aquatic species
(Table 3)  nor were any found for adequately assessing human health
effects (Table 4).   Given the minimal data base, it is suggested that
the advisory be based on the LC50 concentrations found in the aquatic
data,  that of 286 ppm for Tubifex tubifex.  The advisory  concentration
would be calculated by dividing this value by 2, to approximate an
LCI, then by 10 to estimate a possible chronic value.  This would mean
a maximum allowable concentration of 14.3 mg/L to protect aquatic
life.

    A value designed to protect human health  should take  into account
the bioconcentration factor,  and potential contamination  by HCB.  If
HCB is assumed to comprise 9% of DCPA by weight, assuming consumption
of contaminated organisms and water,  then, the  maximum concentration
which would not exceed the 10~6 risk level is 8 ng/L.  This value,
derived from the AWQ Criteria Document  for Chlorinated Benzenes (U.S.
EPA, 1980) takes into  account a  bioconcentration potential for HCB of
8,690.

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     TABLE 3.  DATA REQUIREMENTS FOR CALCULATION OF AQUATIC LIFE
               INTERIM CRITERIA—DCPA
Criterion Requirements
   Aquatic Toxicity

Acute Test Results from tests on:

  A salmonid  (class Osteichthyes)

  A warm water species
  commercially or recreationally
  important (class Osteichthyes)

  Another family in the phylum
  Cordata (fish, amphibian, etc.)

  A planktonic crustacean
  (cladoceran, copepod, etc.)

  Benthic crustacean  (ostracod,
  isopod, scud, crayfish, etc.)

  Insect  (mayfly, dragonfly,
  damselfly, stonefly, mosquito,
  etc.)

  Phylum other than Arthropoda/
  Chordata  (Rotifera, Annelida,
  Mollusca)

  Another family of insect

Acute-chronic ratios with species from
three different families:

  One fish

  One invertebrate

  Acutely sensitive freshwater
  animal species

Acceptable test results from a
test with:

  Freshwater algae

  A vascular plant

Bioaccumulation factor with a
freshwater species (if a maximum
permissible tissue concentration
is available)
Available
  Data
   NO



   NO


   NO


   NO


   NO



   NO


   YES


   NO
       Data
   Acceptability
   NO

   NO


   NO
   NO

   NO



   YES
    NO; QA/QC
   not reported
    NO; not a
freshwater species

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         TABLE 4.  DATA REQUIREMENTS FOR CALCULATION OF HUMAN
                   INTERIM CRITERIA—DCPA
Criterion Requirements
 Human Health Effects
Available
  Data
     Data
Acceptability
Non-Threshold:
  Carcinogen                              NO
  Tumor incidence tests (Incidence of
    tumor formation significantly more
    than the control for at least one     N/A
    dose level, or
  Data set which gives estimate of
    carcinogenetic risk, or               N/A
  Lifetime average exposure tests, or     N/A
  Human epidemiology studies
    (if available, not required)          N/A

Threshold:
  Non-carcinogens                         YES*
  No observed adverse effect level
    (at least 90-day), or                 NO
  Lowest observed effect level            NO
  Lowest observed adverse effect level    NO

Acceptable Daily Intake:
  Daily water consumption                 YES

  Daily fish consumption                  YES

  Bioconcentration factor                 NO
  Non-fish dietary intake                 YES

  Daily intake by inhalation              NO

Threshold Limit Value:
  (Based on 8-hour time-weighted
    average concentrations in air)        NO

Inhalation Studies:
  Available pharmacokinetic data          NO
  Measurements of absorption efficiency   NO
  Comparative excretion data              NO
                    YES
              (EPA assumption)
                    YES
              (EPA assumption)

                    YES
              (EPA assumption)
N/A = Not Applicable
* NOEL available  (not acceptable data)

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U.S. Environmental Protection ARency
Region 5, Library (PL-12J)
77 West Jackson Boulevar.d, 12th Floor
Chicago,  IL  60604-3590

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                              REFERENCES

Burns, J.E.,  F.M.  Miller, E.D. Gomes, and R.A. Albert.  1974.
Hexachlorobenzene exposure from contaminated DCPA in vegetable
spraymen.  Arch.  Environ. Health  29:192-194.

Cabral,  J.R.P.,  P. Shubik, T. Mollner, and F. Raitano.  1977.
Carcinogenesis study in hamsters with hexachlorobenzene.  Toxicol.
Appl. Pharmacol  41:155.

Cabral,  J.R.P.,  T. Mollner, F. Raitano, and P. Shubik.  1978.
Carcinogenesis study in mice with hexachlorobenzene.  Toxicol. Appl.
Pharmacol.   45:323.

CTCP.  1976.   4th ed.   Article by Gosselin.   Abstracted from
Toxicology Data Base.

Federal  Register  (FR).   1980.   U.S.  Government Printing Office,
Washington,  D.C.   November  28,  45(231) :79347-79356.

Kurinnyi,  A.I.,  M.A. Pilinskaya,  I.V. German, and T.S. L'vova.  1982.
Implementation of a program of cytogentic activity and potential
mutagenic hazard of  24 pesticides..   Cytol Genet 16:50-53.

McEwen,  F.L.  and G.R.  Stephenson.   1979.   The use and significance of
Pesticides in the environment.  John Wiley and Sons,  Inc., New York.

Miller,  F.M. and  E.D. Gomes.   1974.   Detection of DCPA residues in
environmental samples.   Pestic. Monit.  J. 8:53-58.

NIOSH RTECS ONLINE File.   82/8007.  Abstracted from Toxicology Data
Base.

Stephan,  C.  E.,  D. I. Mount, D. J. Hansen, J. N.  Gentile, G. A.
Chapman,  and W.  A.  Brungs.   1985.  Guidelines for deriving numerical
national water quality criteria for the protection of aquatic
organisms and their  uses.  Draft.  U.S.  Environmental Protection
Agency, Office of Research and Development,  Environmental Research
Laboratories, Duluth, Minnesota.

U.S.  EPA.   1980.  Ambient Water Quality Criteria  Document for
Chlorinated Benzenes.  Available through National Technical
Information Service  - PB81-117392.

Voronkin, A.S.,  and Y.T.  Loshakov.   1973.   Toxic  effect of pesticides
on Tubifex tubifex.  ESKP. Vodn.  Toksikol. 5:169-178.

Weed Science Society of America  (WSSA).  1979.  Herbicide Handbook 4th
ed.

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