_                                   August,  1987
                         820K88103
              DACTHAL

          Health Advisory
      Office of Drinking Water
U.S.  Environmental Protection Agency
                                                                               -_—

                                                                            !   O
I. INTRODUCTION
        The Health Advisory  (HA)  Program,  sponsored by  the Office of  Drinking
   Water (ODW),  provides  information  on  the health effects, analytical  method-
   ology and treatment  technology that would  be  useful  in dealing with  the
   contamination of  drinking water.   Health Advisories  describe  nonregulatory
   concentrations of drinking water contaminants at which adverse health  effects
   would not be  anticipated  to occur  over  specific exposure durations.  Health
   Advisories contain a margin of safety to protect sensitive members of  the
   population.

        Health Advisories serve  as informal technical guidance to assist  Federal,
   State and local officials responsible for  protecting public health when
   emergency spills  or  contamination  situations  occur.  They are not  to be
   construed as  legally enforceable Federal standards.  The HAs  are subject to
   change as new information becomes  available.

        Health Advisories are developed  for one-day, ten-day, longer-term
   (approximately 7  years, or 10% of  an  individual's lifetime) and  lifetime
   exposures based on data describing noncarcinogenic end points of toxicity.
   Health Advisories do not  quantitatively incorporate  any potential  carcinogenic
   risk from such exposure.   For  those substances that  are known or probable
   human carcinogens, according  to the Agency classification scheme (Group A or
   B),  Lifetime  HAs  are not  recommended.   The chemical  concentration  values for
   Group A or B  carcinogens  are  correlated with  carcinogenic risk estimates by
   employing a cancer potency (unit risk)  value  together with assumptions for
   lifetime exposure and  the consumption of drinking water.  The cancer unit
   risk is usually derived from  the linear multistage model with 95%  upper
   confidence limits.   This  provides  a low-dose  estimate of cancer  risk to
   humans that is considered unlikely to pose a  carcinogenic risk in  excess
   of the stated values.   Excess  cancer  risk  estimates  may also  be  calculated
   using the One-hit, Weibull, Logit  or  Probit models.  There is no current
   understanding of  the biological mechanisms involved  in cancer to suggest that
   any one of these  models is able to predict risk more accurately  than another.
   Because each  model is  based on differing assumptions, the estimates  that are
   derived can differ by  several  orders  of magnitude.

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      Dacthal
                August, 1987
                                           -2-
II.    GENERAL INFORMATION AND PROPERTIES
CAS No. 1861-32-1
Structural Formula

cu
CK
CQgCHa
^c,
V^ci
COjCHs
                            Dimethyl tetrachloroterephthalate
      Synonyms
      Uses
           e  2,3,5,6-Tetrachlorodimethyl-1,4-benzenedicarboxylic acid; DCPA;
              Chlorothal;  Dacthalor;  DAC;  DAC-4;  DAC-893;  DCP (Meister, 1983).
           0  Selective pre-emergence herbicide used to control various annual
              grasses in turf, ornamentals, strawberries, certain vegetable
              transplants, seeded vegetables, cotton, soybeans and field beans
              (Meister, 1983).
      Properties  (Meister, 1983; Windholz et al., 1983; CHEMLAB, 1985)
              Chemical Formula
              Molecular Weight
              Physical State (25°C)
              Boiling Point
              Melting Point
              Density (°C)
              Vapor Pressure (258C)
              Specific Gravity
              Water Solubility (25°C)
              Log Octanol/Water Partition
                Coefficient
              Taste Threshold
              Odor Threshold
              Conversion Factor
C10H604C14
331.99
Crystals

156°C
5,000 mg/L
4.15 (calculated)
      Occurrence
           0  Dacthal has been found in 462 of 1,818 surface water samples analyzed
              and in 33 of 615 ground water samples (STORET, 1987).  Samples were
              collected at 551 surface water locations and 576 ground water locations,

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     Dacthal                                                 August,  1987

                                          -3-
             and  dacthal was  found  in  eight states.   The  85th  percentile  of  all
             nonzero  samples  was  0.39  ug/L in  surface water  and  0.05 ug/L in
             ground water  sources.   The maximum concentration  found  was 8.74 ug/L
             in surface water and 0.05 ug/L in ground water.

     Environmental Fate

          0   In aqueous solutions,  dacthal is  stable  to photolysis with a half-
             life of  greater  than one  week.  -Dacthal  is stable to soil photolysis
             (Registrant CBI  data).

          0   Soil metabolism  of dacthal proceeds with a half-life of greater than
             2-3  weeks.  Degradation rate is affected by  temperature.  No degra-
             dation of dacthal has  been observed in sterile  soils  (half-life of
             1,590 days) (Registrant CBI data).

          0   Degradation products of dacthal include  monomethyltetrachlorotere-
             phthalate  (MTP)  and  tetrachloroterephthalic  acid  (TTA)  (Registrant
             CBI  data).

          0   TTA  has  been  shown to  be  very mobile  in  soils whereas dacthal is not
             (Registrant CBI  data).


III.  PHARMACOKINETICS

     Absorption

          0   Hazleton Laboratories  (no date) reported that humans  receiving  single
             oral doses of dacthal  (25 or 50 mg) excreted up to  6% of  the 25 mg
             dose in  urine as metabolites over a 3-day period.  Approximately
             12%  of the 50 mg dose  was metabolized and excreted  over a similar
             time period.   The data indicated  that up to  12% of  a  50 mg dose
             could be absorbed in humans.

          0   Skinner  and Stallard (1963) reported  that following administration  of
             single oral doses of dacthal  (100 or  1,000 mg/kg) by capsule to dogs,
             90 and 97% of the administered doses  were eliminated as the  parent
             compound in the  feces  by  24 and 96 hours, respectively.  Approximately
             3% of dacthal was converted to the monoethylester of  tetrachloro-
             t«rephthalic  acid (DAC 1449).  Two percent was  eliminated in the
             urine and  1%  in  the  feces.  Less  than 1% (0.07%)  of DAC 1449 was
             converted  to  tetrachloroterephthalic  acid  (DAC  954), which was  also
             excreted in the  urine. The results indicated that  dacthal was
             absorbed poorly  (about 3%) from the gastrointestinal tract of dogs.

     Distribution

          0   Skinner  and Stallard (1963) reported  that following a single oral
             dose of  dacthal  (100 or 1,000 mg/kg)  to  dogs, there was no storage  of
             dacthal  in the kidneys, liver or  fat.  However, DAC 954 was  found in
             the  kidneys.   The authors also reported  that no dacthal was  found in
             the  kidneys or liver of dogs that had been administered dacthal-T at

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    Dacthal                                                August,  1987
            10,000 ppm  (250 mg/kg/day) in the diet for two years.   The  kidneys,
            liver and fat contained DAC  1449, while the kidneys contained  DAC 954
            only.  Both dacthal and DAC  1449 were found in the fat  of dogs treated
            with 10,000 ppm.
    Metabolism
            Hazleton Laboratories  (no date) reported that humans who  took  single
            oral doses of dacthal  (25 or 50 mg) converted 3 to  4%  of  the dose  to
            DAC 1449 within  24 hours.  After  3 days, approximately 6% of the
            25 mg dose and 11% of  the 50 mg dose were converted to DAC 1449.  At
            either dose, less than 1% was converted to DAC 954  in  the 1- or
            3-day time period.

            Skinner and Stallard  (1963) reported that in dogs administered single
            oral doses of dacthal,  small amounts were converted to DAC 1449  (3%)
            or DAC 954 (0.07%).

            Hazleton and Dieterich (1963) reported similar results when dogs were
            administered dacthal  (10,000 ppm;  250 mg/kg bw) in  the diet for
            2 years.
    Excretion
            In human studies  (Hazleton Laboratories, no date),  6% of  a  single
            25 mg oral dose was  excreted  in  urine as DAC  1449 and 0.5%  as  DAC  954
            over a  three-day  period.  Approximately 11% of the  50 mg  dose  was
            converted to  DAC  1449 and 0.6% was converted  to DAC 954.  The  parent
            compound was  not  found  in the urine at either dose.

            Skinner and Stallard (1963) reported that  following the administra-
            tion of a single  oral dose  (100  or 1,000 mg/kg) to  dogs,  90 and 97%
            was eliminated unchanged in the  feces at 24 hours and 96  hours,
            respectively.  Approximately  3%  was converted to DAC 1449;  of  this
            3%, 2%  was eliminated in the  urine and  1%  in  the feces.
IV.  HEALTH EFFECTS
    Humans
            Hazleton Laboratories  (no date)  reported  that dacthal,  administered
            as single 25 mg  or  50  mg  oral  doses  to each  of  six  volunteer subjects,
            did not cause any observable effects.  Assuming 70  kg  body weight,
            these amounts correspond  to doses  of  0.36 or 0.71 mg/kg.   Hemograms,
            liver,  kidney and urine analyses from the six human volunteers were
            normal.
    Animals
       Short-term Exposure

         0  The acute  oral  LD5Q for male  and  female  rats was  reported to be
            greater than 12,500 mg/kg (Wazeter  et  al.,  1974a).

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Dacthal                              '                  August,  1987

                                     -5-
     0  The acute oral LD50 for male and female beagle dogs was reported to
        be greater than 10,000 mg/kg (Wazeter et al.,  1974b).

     0  Keller and Kundzin (1960)  administered pure dacthal to weanling
        male Sprague-Dawley rats (10/dose)  in the diet for 28 days at dose
        levels of 0, 0.0082,  0.0824 or 0.824%.  Based  upon body weight and
        compound consumption data  provided  by the investigators,  these dietary
        levels correspond to approximately  0, 7.6, 78.6 or 758 mg/kg/day.
        Following treatment,  no effects on  growth, food consumption,  survival,
        body weights,  organ weights, gross  pathology  and histopathology were
        observed.  This study identifies a  NOAEL of 758 mg/kg/day (the highest
        dose tested).

     0  Keller (1961)  reported that oral administration (by capsule)  of
        800 mg/kg/day  of DCPA (% a.i. unknown) to beagle dogs (two/sex) for
        28 days resulted in loss of body weight, reduced appetite, increased
        liver weight and liver to  body weight ratio,  centrilobular liver
        congestion and degeneration.

   Dermal/Ocular Effects

     0  The acute dermal LD50 value for albino rabbits was reported to be
        greater than 10,000 mg/kg  (Elsea, 1958).  He also reported that
        dacthal, when  applied to rabbit skin, did not cause irritation or
        sensitization.

     0  Johnson et al. (1981) applied dacthal (2,000 mg/kg) for 24 hrs to
        shaved intact  or abraded back or flank skin of New Zealand rabbits
        (five/sex) in  a paste form.  Desquamation (which ranged from  very
        slight to slight) and very slight erythema were observed.  There was
        no macroscopic or microscopic pathology noted, and dacthal caused no
        signs of irritation or sensitization.

     0  A single application of 3.0 mg of dacthal to the eyes of albino
        rabbits produced a mild degree of irritation that subsided completely
        within 24 hours following  treatment (Elsea, 1958).

   Long-term Exposure

     0  Wazeter et al. (1977) fed  CD rats (15/sex/dose) disodium dacthal in
        the diet for 90 days at dose levels of 0, 50,  500, 1,000 or 10,000 ppm.
        Based upon compound consumption and body weight data provided by the
        authors, these dietary levels are approximately 0, 3.6, 36.4, 74 or
        732 mg/kg/day  for males and 0, 4.2, 43.2, 82.3 or 856 mg/kg/day
        for females.  General behavior, appearance, body weight,  food con-
        sumption, ophthalmoscopic  evaluation, hematology, clinical chemistry,
        urinalysis, gross pathology and histopathology were comparable for
        treated and control groups.  A NOAEL of 10,000 ppm (732 mg/kg/day
        for males and  856 mg/kg/day for females, the highest dose tested)
        was identified for this study.

     0  Hazleton and Dieterich (1963) fed beagle dogs  (four/sex/dose) dacthal
        in the diet at 0, 100, 1,000 or 10,000 ppm for two years.  Based upon

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Dacthal                                                August, 1987

                                     -6-
        body weight and food consumption data provided in the report, these
        dietary levels are approximately 0,  2.6,  17.7 or 199 mg/kg/day for
        males and 0,  3, 20.7 or 238 mg/kg/day for females.   Physical
        appearance, behavior, food consumption,  hematology, biochemistry,
        urinalysis, organ weight,  organ-to-body  weight ratio, gross pathology
        and histopathology were comparable in treated and control groups at
        all dose levels.   A NOAEL of 10,000 ppm  (199 mg/kg/day for males and
        238 mgA9/day for females; the highest dose tested) was identified
        for this study.

     e  Paynter and Kundzin (1963) fed albino rats (35/sex/dose;  70/sex for
        controls) dacthal in the diet for 2 years at 0, 100, 1,000 or
        10,000 ppm.  Based on food consumption and body weight data
        provided in the report, these dietary levels correspond approximately
        to 0, 5, 50 or 500 mg/kg/day.  Physical  appearance, behavior, hematology,
        biochemistry, organ weights, body weights, gross pathology and histo-
        pathology of treated and control animals were monitored.   After 3
        months at 10,000 ppm, slight hyperplasia of the thyroid was reported
        in both sexes.  After 1 year, increased  hemosiderosis of the spleen
        of females occurred at 10,000 ppm and there were slight alterations
        in the centrilobular cells of the liver  of both sexes.  Kidney weights
        were increased significantly in males fed 10,000 ppm at the end of
        the 2-year study.  Based on these data,  a NOAEL of 1,000 ppm
        (50 mgA9/day) was identified.

   Reproductive Effects

     0  Paynter and Kundzin (1964) conducted a two-generation study using
        albino rats.  Animals (8 males/16 females) were fed dacthal in the
        diet at dose levels of 0,  0.1 or 1.0% for 24 weeks, prior to mating.
        Assuming that 1 ppm in the diet of rats  is equivalent to 0.05 mg/kg/day
        (Lehman, 1959), this corresponds to doses of 0, 50 or 500 mg/kg/day.
        This study reported an evaluation of data collected on the second
        parental generation (P^) and through weaning of the first litter
        (F2a).  The authors reported that a second litter (F2t>) was n°t
        obtained.  Following treatment, the following indices were evaluated;
        fertility, gestation, live births and lactation.  Since the fertility
        index was  37%  (6/16) at the 1% dose, 75% (12/16) at the 0.1% dose,
        and only 19%  (3/16) in controls, no conclusions could be reached.
        The lactation index for the 0.1% group was significantly lower than
        controls.  No oth^r adverse reproductive effects were observed.

     0  Hazleton (1963) performed a one-generation reproduction study in
        albino rats.  Animals were given dacthal in the diet at 0, 1,000 or
        10,000 ppm in the diet.  Assuming that 1 ppm in the diet of rats is
        equivalent to 0.05 mg/kg/day  (Lehman, 1959), this corresponds to
        doses of about 0, 50 or 500 mg/kg/day.  No effects were detected on
        fertility, gestation, number of live births or lactation.  Based on
        this information a NOAEL of 10,000 ppm (500 mg/kg/day; the highest
        dose tested)  was identified.

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   Dacthal                                                August,  1987 «

                                        -7-


      Developmental Effects^

        0  Powers (1964)  fed  pregnant New Zealand rabbits (six/dose)  dietary
           levels of dacthal-T (0,  1,000 or 10,000 ppm)  on days 8 to  16 of
           gestation.  Assuming that 1  ppm in the diet of rabbits is  equivalent
           to 0.03 mg/kg/day  (Lehman,  1959),  this corresponds to about 0,  30 or
           300 mg/kg/day.   Following treatment,  fetal toxicity (number of  live/dead
           or resorptions), maternal effects  (appearance, behavior, body weight)
           and visceral and skeletal anomalies were evaluated.   No adverse
           effects were observed at any dose  level tested,  This study identified
           a developmental  NOAEL of 300 mg/kg/day (the highest dose tested).

      Mutagenicity

        0  No significant increase  in mutation frequency was observed in Droso~
           phila melanogaster larvae that had been fed media containing 0.1  to
           10 mM dacthal (Paradi and Lovenyak, 1981).

        0  Dacthal had no  mutagenic activity  in Salmonella assays (Microbiological
           Associates, 1977a),  in in vivo cytogenetic tests (Microbiological
           Associates, 1977b),  in DNA repair  tests (Microbiological Associates,
           1977c) or in dominant lethal tests (Microbiological Associates, 1977d).

      Carcinogenicity

        0  Paynter and Kundzin  (1963)  fed albino rats (35/sex/dose;  70/sex for
           controls) dacthal-T  for  2 years at dose levels of 0, 100,  1,000 or
           10,000 ppm.  Based upon  compound consumption and body weight provided
           in the report,  these dietary levels correspond approximately to 0, 5,
           50 or 500 mg/kg/day.  Based on gross and histologic examination,  neo-
           plasms of various  tissues and organs were similar in type, localization,
           time of occurrence,  and incidence in control and treated animals.


V. QUANTIFICATION OF TOXICOLOGICAL EFFECTS

        Health Advisories  (HAs) are generally determined for one-day, ten-day,
   longer-term (approximately 7 years)  and lifetime exposures if adequate  data
   are available that identify  a sensitive noncarcinogenic end point  of toxicity.
   The HAs for noncarcinogenic  toxicants are  derived using the following formula:

                 HA = (NOAEL  or LOAEL)  x (BW) . 	   /L (	   /r}
                        (UP)  x  (    L/day)
   where:
           NOAEL or LOAEL *  No-  or  Lowest-Observed-Adverse-Effect-Level
                            in mg/kg  bw/day.

                       BW =  assumed body  weight of  a  child  (10  kg)  or
                            an adult  (70  kg).

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Dacthal                                         ,       August, 1987

                                     -8-
                    UF » uncertainty factor (10, 100 or 1,000), in
                         accordance with NAS/ODW guidelines.

             	 L/day «• assumed daily water consumption of a child
                         (1 L/day) or an adult (2 L/day).


One-day Health Advisory

     No information was found in the available literature that was suitable
for deriving a One-day HA.  The study in humans by Hazleton Laboratories  (no
date) was not selected since only low doses (0.36 or 0.71 mg/kg) were tested,
and longer-term studies in animals suggest the no-effect level may be much
higher.  It is, therefore, recommended that the Ten-day HA value for the
10-kg child (75 mg/L; calculated below) be used at this time as a conservative
estimate of the One-day HA.

Ten-day Health Advisory

     The 28-day feeding study in rats by Keller and Kundzin (1960) has been
selected to serve as the basis for determination of the Ten-day HA.  In this
study, no adverse effects on growth, organ weight, food consumption, gross
pathology or histopathology were detected at 758 mg/kg/day.

     The Ten-day HA for the 10-kg child is calculated as follows:

         Ten-day HA =  (758 mg/kg/day)  (10 kg) = 75   /L (75 000 ug/L)
                           (100)  (1 L/day)

where:

        758 mg/kg/day  = NOAEL, based on absence of effects on growth, organ
                        weight, food consumption, gross pathology or
                        histopathology in rats fed dacthal for 28 days.

                1 0 kg  = assumed body weight of a child.

                   100  = uncertainty factor, chosen in accordance with NAS/ODW
                        guidelines for use with a NOAEL from an animal study.

               1 L/day  = assumed daily water consumption of a child.

Longer-term Health Advisory

     No appropriate data were available for the calculation of a Longer-term
HA.  Therefore, it is  recommended that the modified DWEL, adjusted for a  10-kg
child  (5 mg/L), be used at this  time as a conservative estimate for a Longer-
term HA.

Lifetime Health Advisory

     The Lifetime HA represents  that portion of an individual's total exposure
that is attributed to  drinking water and is considered protective of noncar-
cinogenic adverse health effects  ove-r  a lifetime exposure.  The Lifetime  HA

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Dacthal                                                August, 1987

                                     -9-
is derived in a three step process.  Step 1 determines the Reference Dose
(RfD), formerly called the Acceptable Daily Intake (ADI).  The RfD is an esti-
mate of a daily exposure to the human population that is likely to be without
appreciable risk of deleterious effects over a lifetime, and is derived from
the NOAEL (or LOAEL), identified from a chronic (or subchronic) study, divided
by an uncertainty factor(s).  From the RfD, a Drinking Water Equivalent Level
(DWEL) can be determined (Step 2).  A DWEL is a medium-specific (i.e., drinking
water) lifetime exposure level, assuming 100% exposure from that medium, at
which adverse, noncarcinogenic health effects would not be expected to occur.
Ihe DWEL is derived from the multiplication of the RfD by the assumed body
weight of an adult and divided by the assumed daily water consumption of an
adult.  The Lifetime HA is determined in Step 3 by factoring in other sources
of exposure, the relative source contribution (RSC).  The RSC from drinking
water is based on actual exposure data or, if data are not available, a
value of 20% is assumed for synthetic organic chemicals and a value of 10%
is assumed for inorganic chemicals.  If the contaminant is classified as a
Group A or B carcinogen, according to the Agency's classification scheme of
carcinogenic potential (U.S. EPA, 1986a), then caution should be exercised in
assessing the risks associated with lifetime exposure to this chemical.

     The 2-year study in rats by Paynter and Kundzin (1963) has been selected
to serve as the basis for determination of the Lifetime HA value for dacthal.
This study identified a NOAEL of 50 mg/kg/day, based on absence of effects on
appearance, behavior, hematology, blood chemistry, organ weight, body weight,
gross pathology and histopathology in male rats.   The LOAEL was 500 mg/kg/day,
based on thyroid hyperplasia, histological changes in the liver and increased
kidney weights.

     Using this study, the Lifetime HA is derived as follows:


Step 1:  Determination of the Reference Dose (RfD)

                     RfD = .(..50 mg/kg/day) . 0.5 mg/kg/day


where:

        50 mg/kg/day = NOAEL, based on absence of toxic effects in rats
                       exposed to dacthal in the  diet for two years.

                 100 = uncertainty factor,  chosen in accordance with NAS/ODW
                       guidelines for use with a  NOAEL from an animal study.

Step 2:  Determination of the Drinking Water Equivalent Level (DWEL)

           DWEL = (0.5 mg/kg/day) (70 kg) = 17.5  mg/L (17,500 ug/L)
                         (2 L/day)

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     Dacthal                                                August,  1987

                                          -10-


     where:

             0.5 mg/kg/day « RfD.

                     70 kg = assumed body weight of an adult.

                   2 L/day = assumed daily water consumption of an adult.

     Step 3:  Determination of  the  Lifetime Health Advisory

                Lifetime HA * (17.5 mg/L) (20%)  = 3.5 mg/L (3,500 ug/L)

     where:

             17.5 mg/L « DWEL.

                   20% = assumed relative source contribution from water.

     Evaluation of Carcinogenic Potential

          0   Paynter and Kundzin (1963)  fed dacthal to rats for 2 years and
             reported no evidence of carcinogenic effects at dose levels up to
             10,000 ppm (450 mg/kg/day for males and 555 mg/kg/day in females).
          •  This study is limited  in that the relatively small numbers of animals
             used (35/sex/dose; 70/sex for controls) and the removal of animals
             (10/sex/dose; 20/sex for controls)  for interim sacrifice may have
             resulted in there  being too few animals available for observation of
             late-developing tumors.

          e   The International  Agency for Research on Cancer has not evaluated the
             carcinogenic potential of dacthal.

          0   Applying the criteria  described in EPA's guidelines for assessment of
             carcinogenic risk  (U.S. EPA, 1986a), dacthal may be classified in
             Group D: not classified.  This category is for substances with inade-
             quate animal evidence  of carcinogenicity.


 VI.  OTHER CRITERIA, GUIDANCE AND STANDARDS

          •   The U.S. EPA has established residue tolerances for dacthal in or on
             raw agricultural commodities that range from 0.5 ppm to 15.0 ppm
             (U.S. EPA, 1985).


VII.  ANALYTICAL METHODS

          0   Analysis of dacthal is by a gas chromatographic (GC) method applicable
             to the determination of certain chlorinated pesticides  in water
             samples (U.S. EPA, 1986b).   In this method, approximately 1 liter of
             sample is extracted with methylene chloride.  The extract is concen-
             trated and the compounds are separated using capillary  column GC.
             Measurement is made using an electron-capture detector.   The method

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      Dacthal                                                August,  1987

                                           -11-
              detection limit has not been determined for dacthal,  but it is estimated
              that the detection limits  for analytes included in this method are in
              the range of 0.01  to 0.1 ug/L.


VIII. TREATMENT TECHNOLOGIES

           0  Reverse osmosis (RO)  is a  promising treatment method  for pesticide-
              contaminated waters.   As a general  rule, organic compounds  with
              molecular weights  greater  than 100  are candidates for removal  by RO.
              Larson et al.  (1982)  report 99% removal efficiency of chlorinated
              pesticides by  a thin-film  composite polyamide membrane operating at a
              maximum pressure of 1,000  psi and a maximum temperature of  113°F.
              More operational data are  required,  however,  to specifically determine
              the effectiveness  and feasibility of applying RO for  the removal of
              dacthal from water.   Also,  membrane adsorption must be considered when
              evaluating RO performance  in the treatment of dacthal-contaminated
              drinking water supplies.

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    Dacthal                                                   August, 1987

                                         -12-


IX.  REFERENCES

    CHEMLAB.  1985.   The  Chemical  Information System,  CIS,  Inc., Bethesda, MD.

    Elsea, J.R.*  1958.   Acute oral administration; acute dermal application; acute
         eye application.   Unpublished  study.  MRID 00045823.

    Hazleton Laboratories,  Inc.*  Undated.  Oral administration - humans.  ODW
         Document No.  0036.

    Hazleton,  L.N.,  and W.H.  Dieterich.*  1963.  Two-year dietary feeding - dogs.
         Final Report.  Unpublished study.  MRID 00083584.

    Hazleton Laboratories,  Inc.*  1963.   Reproduction  study - albino rats.  ODW
         Document No.  0032.

    Johnson, D., J.  Myer  and  A. Olafsson.*  1981.  Acute dermal toxicity  (LD50)
         study in albino  rats.  Unpublished study.   MRID 00110553.

    Keller, J.G.  1961 «,*   28-day oral administration - dogs.  Unpublished study.
         MRID 00083573.

    Keller, J.G., and M.  Kundzin.*  1960.  Twenty-eight day dietary feeding study
         in rats.  Unpublished study.  MRID 00083571.

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Dacthal                                                    August,  1987

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Confidential Business Information submitted to the Office of Pesticides
 Programs.

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