EPA-600/4-85-072 App.
                                   APPENDIX  A
               THE DETERMINATION OF OITHIOCARBAMATES PESTICIDES
                    ~1N WASTEWATER AS  CARBON OISULFIDE BY          ... _.  - _,_
                               GAS  CHROMATOGRAPHY                   DRAFT
                                 METHOD 630.1

1.  SCOPE AND APPLICATION
    1.1  This method covers  the determination  of  certain dithiocarbamates
         pesticides after conversion to carbon  disulfide.   The  following
         parameters can be determined by this  method:

              Parameter                                 CAS.  Ko«

              Amobam                                    3566-10-7
              Susan 40                                  51026-28-9
              Bus an 85                                  128-03-0
              EXD                               - -''•:•'*•• 502-55-6
              Ferbam                                    14484-54-1
              KN Methyl                                 137-41-7
              Metham                                    137-42-8
              Nab am                                     142-59-5
              Nabonate                                  138-93-2
              Sodium dimethyl dithiocarbamate            128-04-1
              Thiram                                    137-26-8
              Zineb                                     12122-67-7
                                                        137-30-4
    1.2  The compounds are decomposed to form carbon  disulfide  (CS?3 and
         the total  dithiocarbamate concentration is measured from the  amount
         of CS2 produced by acid hydrolysis.  Unless  the sample can be
         otherwise  characterized, all results are reported as Ziram.

    1.3  This is a  total residue gas chroma to graphic  (GC) method applicable
         to the determination of the compounds listed above in municipal and
         industrial  discharges as provided under 40 CFR 136.1.  Any

                                               US.  Environmental Protection Agency
                                      32       Region V,  Library
                                               230  South Dearborn Street
                                               Chicago. fUinols  60604

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          modification of this method beyond those expressly permitted,
          shall be considered a major modification subject to application
          and approval of alternate test, procedures under 40 CFR 136.4
          and 136.5,
     1.4  The method detection limits {MDLs, defined in Section  14)
          for the parameters listed in Section 1.1 are listed in Table 1.
          The MOLs for a specific wastewater may differ from those
          listed, depending upon the nature of interferences in  the
          sample matrix.
     1.5  This method is restricted to use by or under the supervision .
          of analysts experienced in the use of gas chromatography and in
          the interpretation of gas chromatograms.  Each analyst must
          demonstrate the ability to generate acceptable results with
          this method using the procedure described in Section 8.2.

2.    SUMMARY OF METHOD1
     2.1  A measured  volume of sample, 5 ml,  is digested with acid to
          yield CS2 by hydrolysis of the dithiocarbamate moiety.  The
          evolved CS* is extracted  from water into hexane.  Gas
          chromatographic conditions  are described which permit the
          separation  and measurement of  CS^in the extract_by gas
          chromatography with a Hall detector in  the sulfur mode.
     2.2  This method provides a cleanup procedure involving purging
          of any indigenous CS2 from the sample at pH 12-13.  This
          procedure is performed using a vortex evaporator.

3.    INTERFERENCES
      3.1  Method  interferences may be caused by  contaminants in  solvents,
           reagents,  glassware,  and other  sample  processing apparatus  that
           lead to discrete artifacts or elevated baselines  in  gas
           chromatograms.  All reagents and  apparatus must  be routinely
           demonstrated to be free  from interferences under the conditions
           of the  analysis by running laboratory  reagent blanks as
           described  in Section 8.5.

                                 33

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                                                       2
          3.1.1  Glassware must be scrupulously cleaned .
                 Clean  all glassware as soon as possible after  use  by
                 thoroughly rinsing with the last  solvent used  1n  1t,
                 Follow by washing with hot water,drain dry,  and  heat  in
                 an oven  or muffle furnace at 400°C for 15-30 minutes.
                 Do not heat  volumetric ware.  Some thermally stable
                 materials such as PCBs may not be eliminated by  this
                 treatment.   Thorough rinsing with acetone  and  pesticide
                 quality  hexane may be substituted for the  heating.
                 After  drying and cooling, seal and store glassware  in  a
                 clean  environment to prevent any  accumulation  of  dust  or
                 other  contaminants.  Store inverted or capped  with
                 aluminum foil.
          3.1.2  The use  of high purity reagents  and solvents
                 helps  to minimize interference problems.   Purification
                 of solvents  by distillation in all-glass systems  may be
                 required.
     3.2  Carbon disulfide may be a direct interferent in wastewaters.
          This method  includes procedures to purge CS2 from the
          wastewater prior to acid hydrolysis of  the sample.  A vortex
          evaporator is used  for CS^ removal.
     3.3  Additional matrix interferences may be  caused by  contaminants
          that are coextracted from the sample and from other C$2
          generating compounds.  The extent of matrix  interferences  will
          vary considerably from source to source, depending upon  the
          nature of the sample.
4.   SAFETY
     4.1  The toxicity or carcinogenicity of each reagent used  in
          this method has not been precisely defined; however,  each
          chemical compound should be treated as  a potential health
          hazard.  From this viewpoint, exposure  to  these chemicals  must
          be reduced to the lowest possible level by whatever means
          available.  The laboratory is responsible  for maintaining  a
          current awareness file of OSHA regulations regarding  the safe

                                   34

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         handling of the chemicals specified 1n this method.  A
         reference file of material data handling sheets should also
         be made available to all personnel Involved 1n the chemical
         analysis.  Additional references to laboratory safety are
                                           3-5
         available and have been Identified    for the Information
         of the analyst.
    4.2  Nabam (ethylenebls(dithiocarbamate)) has been Identified as
         having substantial evidence of cardnogenicity and should
         be handled according to OSHA regulations.
5.  APPARATUS AND MATERIALS
    5,1  Sampling equipment, for discrete or composite sampling.
         5.1.1  Sample containers - 40-mL screw cap vials (Pierce
                No. 13075 or equivalent) each equipped with a
                polytetrafluoroethylene (PTFE)-faced silicone
                septum (Pierce No. 12722 or equivalent).  Prior
                to use, wash vials and septa with detergent and
                rinse with tap and distilled water.  Allow the
                vials and septa to air dry at room temperature,
                place in a 105°C oven for one hour, then remove
                and allow to cool in an area known to be free of
               • organics.
         5.1.2  Automatic sampler (optional) - Must incorporate
                glass sample containers for the collection of a
                minimum of 250 ml.  Sample containers must be
                kept refrigerated at 4°C and protected from light
                during compositing.  If the sampler uses a peristaltic
                pump, a minimum length of compressible silicone rubber
                tubing may be used.  Before use, however, the compres-
                sible tubing should be thoroughly rinsed with methanol,
                followed by repeated rinsings with distilled water to
                minimize the potential for contamination of the sample.
                An integrating flow meter is required to collect flow
                proportional composites.
    5,2  Glassware
         5.2.1  Centrifuge tube - 15-mL, conical with Teflon-lined
                screw cap.
                                    35

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          5.2.2  Volumetric flask - 250-mL with glass stopper.
          5.2.3  Bottles - 100- to 200-mL capacity with Teflon-lined
                 screw caps.
     5.3  Vortex Evaporator - Buchler 3-2200, equipped with sample
          block to hold 36 15-mL conical bottom centrifuge tubes and
          appropriate vacuum cover.
     5.4  Water bath - Heated, capable of temperature control (±2°C).
          The bath should be used in a hood.
     5.5  Balance - Analytical, capable of accurately weighing to the
          nearest 0.0001 g.
     5.6  Gas chromatograph - Analytical system complete with gas
          chromatograph suitable for on-column injection and all required
          accessories including syringes, analytical columns, gases,
          detector, and strip-chart recorder.  A data system is recommended
          for measuring peak areas.
          5.6.1  Column - 180 cm x 2 mm ID glass, packed with
                 O.U SP-1000 on Carbopack C (80/100 mesh) or equivalent.
                 This column was used to develop the method performance
                 statements in Section 14.  Alternate columns may be used
                 in accordance with the provisions described in Section
                 11.1.
          5.6.2  Detector - Hall detector operated in the sulfur mode.
                 This detector has proven effective in the analysis of
                 wastewaters for the compounds listed in the scope and was
                 used to develop the method performance statements in
                 Section 14.
6.  REAGENTS
    6.1  Reagent water - Reagent water is defined as a water in which
         an interferent is not observed at the MDL of each parameter
         of interest.
    6.2  Hexane - Distilled-in-glass quality or equivalent.
    6.3  Sulfuric acid,  12 N -  Slowly add 100 ml concentrated sulfuric
         acid to 200 ml  reagent water.
    6.4  Sodium phosphate,  tribasic,  dodeca-hydrate  -  Baker  reagent
         grade or equivalent.
                                     36

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6.5  Tribasic sodium phosphate, 0.1 M - Dissolve 38 g of tribasic
     sodium phosphate in reagent water and dilute to 1000 ml with
     reagent water.
6.6  Stannous chloride - SnCl2 2H20, ACS grade.
6.7  Stannous chloride reagent - Dissolve 1.5 g stannous chloride
     in 100 ml 12 N_ sulfuric acid.  Prepare fresh daily.
6.8  Sodium chloride - Heated at 450°C for eight hours.
6.9  Stock standard solutions (0.1 yg/yL) - Stock standard
     solutions can be prepared from pure standard materials
     or purchased as certified solutions.
     6.9.1  Prepare dithiocarbamate spiking solutions by
            accurately weighing about 0.025 grams of pure
            material.  Dissolve the material in 0.1 M
            Na3P04 and dilute to volume in a 250-mL
            volumetric flask.  Larger volumes can be
            used at the convenience of the analyst.  If
            compound purity is certified, at 96% or greater,
            the weight can be used without correction to
            calculate the concentration of the stock standard.
            Commercially prepared stock standards can be used
            at any concentration if they are certified by the
            manufacturer or by an independent source.
     6.9.2  (0.1 yg/yL) Prepare C$2 stock standard solution
            by adding 7.9 yL of CS2 to hexane and diluting
            to volume in a 100-mL volumetric flask.
     6.9.3  Transfer the stock standard solutions into
            Teflon-sealed screw cap bottles.  Store at 4°C.
            Frequently check standard solutions for signs
            of degradation or evaporation.
     6.9.4  Stock standard solutions must be replaced after
            six months or sooner if comparison with check
            standards indicates a problem.
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7.   CALIBRATION
    7.1  Use zlram as the standard for total dithlocarbamates
         when a mixture of dithlocarbamates is likely to be
         present.  Use the specific dithiocarbamate as a standard
         when only one pesticide is present and its identity has
         been established.
    7.2  Establish gas chromatographie operating parameters equivalent
         to those indicated in Table 1.  The gas chromatographic
         system can be calibrated using the external standard technique
         (Section 7.3).
    7.3  External standard calibration procedure:
         7.3.1  Prepare calibration standards at a minimum of three
                concentration levels by adding volumes of the CS-
                stock standard to a volumetric flask and diluting
                to volume with hexane.  One of the external standards
                should be at a concentration near, but above, the
                method detection limit.  The other concentrations
                should correspond to the range of concentrations
                expected in the sample concentrates or should define
                the working range of the detector.
         7.3.2  Using injections of 1 to 5 pL of each calibration
                standard, tabulate peak height or area responses
                against the mass injected.  The results can be
                used to prepare a calibration curve for CS-.
                Alternatively, the ratio of the response to the
                mass injected, defined as the calibration factor
                (CF), can be calculated at each standard concen-
                tration.  If the relative standard deviation of
                the calibration factor is less than 10% over the
                working range, the average calibration factor can
                be used in place of a calibration curve.
         7.3.3 -The working calibration curve or calibration factor
                must be verified on each working shift by the
                measurement of one or more calibration standards.
                                    38

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                 If the response for CS- varies from the predicted
                 response by more than ±10%, the test must be
                 repeated using a fresh calibration standard.
                 Alternatively, a new calibration curve or
                 calibration factor must be prepared.
     7.4  Before using any cleanup procedure, the analyst must process
          a series of calibration standards through the procedure to
          validate the absence of interferences from the reagents.
8.  QUALITY CONTROL
    8.1  Each  laboratory using  this method  is  required  to operate  a
         formal quality control  program.  The  minimum requirements of
         this  program  consist  of  an initial  demonstration of  laboratory
         capability  and the  analysis  of  spiked  samples  as a  continuing
         check on  performance.   The laboratory is  required to maintain
         performance records to  define the  quality of data that  is
         generated.
         8.1.1  Before performing  any analyses, the analyst  must
                demonstrate  the  ability  to  generate acceptable accuracy
                and  precision  with this  method.  This ability is
                established  as  described  in  Section 8.2.
         8.1.2  In recognition  of  the rapid  advances occurring in
                chromatography,  the analyst  is  permitted certain options
                to improve the  separations  or  lower the cost of
                measurements.   Each time  such  modifications  to the
                method are made,  the  analyst is required to  repeat the
                procedure in Section  8.2.
         8.1.3  The  laboratory  must spike and  analyze a minimum of
                10%  of all samples to monitor  continuing laboratory
                performance.  This procedure is described in Section 8.4.
    8.2  To establish the ability to generate acceptable accuracy
         and precision, the  analyst must  perform the following
         operations.
         8.2.1   Select a representative spike concentration for each
                compound  to  be  measured.

                                      39

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     8.2.2  Add a known amount of an  Individual  d1th1ocarbamate
            standard to a minimum of  four  5-mL allquots  of  0.1 M
            tribasic sodium phosphate.  A  representative waste-
            water may be used in place of  the reagent  water,  but
            one or more additional allquots must be  analyzed  to
            determine background levels, and the spike level  must
            exceed twice the background level for the  test  to be
            valid.  Analyze the aliquots according to  the method
            beginning in Section 10.
     8.2.3  Calculate the average percent  recovery (R),  and the
            standard deviation of the percent recovery (s), for the
            results.  Wastewater background corrections  must  be made
            before R and s calculations are performed.
     8.2.4  Using the appropriate data from Table 2, determine the
            recovery and single operator precision expected for the
            method, and compare these results to the values measured
            in Section 8.2.3.  If the data are not comparable, the
            analyst must review potential  problem areas  and repeat
            the test.
8.3  The analyst must calculate method performance criteria and
     define the performance of the laboratory for each spike
     concentration and parameter being measured.
     8.3.1  Calculate upper and lower control  limits for method
            performance as follows:

            Upper Control Limit (UCL) = "R  + 3 s
            Lower Control Limit (LCD - Fl  - 3 s

            where R and S are calculated as in Section 8.2.3. The
            UCL and LCL can be used to construct control charts6
            that are useful in observing trends  in performance.
     8.3.2  The laboratory must develop and maintain separate accuracy
            statements of laboratory performance for wastewater
            samples.  An accuracy statement for  the  method  is
                                40

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            defined as R ± s.  The accuracy statement should be
            developed by the analysis of four allquots of wastewater
            as described in Section 8.2.2, followed by the
            calculation of R and s.  Alternately, the analyst may
            use four wastewater data points gathered through the
            requirement for continuing quality control in Section
            8.4.  The accuracy statements should be updated
            regularly.
8.4  The laboratory is required to collect in duplicate  a portion
     of their samples to monitor spike recoveries. The frequency of
     spiked sample analysis must be  at least 10% of all  samples or
     one sample per month, whichever is greater.  One aliquot of the
     sample must be spiked and analyzed as described in  Section 8.2.
      If the recovery for a particular compound does not fall within
     the control limits for method performance, the results reported
     for that compound in all samples processed as part  of the  same
     set must be qualified as described in Section 12.3.  The
     laboratory should monitor the frequency of data so  qualified  to
     ensure that it remains at or below 5%.
8.5  Before processing any samples,  the analyst should demonstrate
     though the analysis of a 5-ml aliquot of 0.1 M tribasic
     sodium phosphate that all glassware and reagents interferences
     are under control.  Each time a set of samples is extracted or
     there is a change in reagents,  a laboratory reagent blank
     should be processes as a safeguard against laboratory
     contamination.
8.6  It is recommended that the laboratory adopt additional
     quality assurance practices for use with this method.
     The specific practices that are most productive depend
     upon the needs of the laboratory and the nature of  the
     samples.  Field duplicates may  be analyzed to monitor
     the precision of the sampling technique.  When doubt
     exists over the identification  of a peak on the chromatogram,
     confirmatory techniques such as gas chromatography

                               41

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          with a dissimilar column, specific element detector,
          or mass spectrometer must be used.  Whenever possible,
          the laboratory should perform analysis of standard
          reference materials and participate in relevant performance
          evaluation studies.
9.   SAMPLES COLLECTION. PRESERVATION. AND HANDLING
     9.1  Grab samples must be collected  in  glass  containers.
          Conventional sampling practices  should  be followed;
          however, the bottle must not be prerinsed with  sample
          before collection.  Composite samples  should be collected
          in refrigerated glass containers in accordance with the
          requirements of the program.  Automatic  sampling equipment
          must be as free as possible of plastic and other potential
          sources of contamination.
     9.2  The samples must be iced or refrigerated at 4° C from
          the time of collection until extraction.
     9.3  Add 15.2 g of tribasic sodium phosphate  per 40 ml of  sample
          to the sample to adjust pH to 12-13 at time of collection.

10.  SAMPLE CLEANUP AND EXTRACTION
     10.1 Place 5 ml of sample in a 15-mL conical  centrifuge tube.
     10.2 Add 0.75 g of NaCl and shake tube to dissolve salt.
     10.3 Add 2 ml of MTBE and process in a vortex evaporator
          for 10 min  with the temperature at 30°C, a vacuum
          of 30 inches Hg, and the vortex speed  control set at 4.5.
     10.4 Repeat step 10.3 twice.
     10.5 Add 0.75 ml of hexane and 2.5 ml of SnC^ reagent to
          the aqueous layer.  Cap tube tightly and invert in a
          water bath at 50°C for 30 min.
     10.6 Remove tube from water bath and let cool inverted
          to room temperatue.
     10.7 Shake tube for 1 min without venting.  Analyze  the hexane
          layer by GC with a Hall detector in the  sulfur mode.
                                    42

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           If CS-  levels  are outside  of  the GC calibration
           range,  the  sample can  be diluted a known amount  with
           hexane  and  reanalyzed.
11.   GAS CHROMATOGRAPHY
     11.1 Table 1 summarizes the recommended  operating conditions for
          the gas chromatograph.  Included  in this table are estimated
          retention time and MDLs that can  be achieved by this method.
          An example of the chromatography  achieved Column 1 is shown
          in Figure 1.  Other packed columns, chromatographic conditions,
          or detectors may be used if the  requirements of Section 8.2
          are met.  Capillary (open-tubular)  columns may also be used if
          the relative standard deviations  of responses for replicate
           injections  are demonstrated  to be less than  6% and  the
           requirements of  Section 8.2  are met.
      11.2  Calibrate the  gas chromatographic system daily as described
           in Section  7.
      11.3  Inject  1 to 5 yl of the sample extract using the  solvent
           flush  technique**.  Record  the volume  injected to  the
           nearest 0.05 H, and  the resulting peak sizes in  area
           or peak  height units.  An  automated system that  consistently
           injects  a constant volume  of  extract  may also be  used.
      11.4  The width of the retention time window used  to make
           identifications  should be  based upon  measurements of
           actual  retention time  variations  of standards over  the
           course  of a day.  Three times  the standard deviation of  a
           retention time for a  compound  can be  used to calculate
           a suggested window size; however, the experience  of the
           analyst  should weigh  heavily  in the interpretation
           of chromatograms.
      11.5  If the  response  for the peak  exceeds  the working  range
           of the  system, dilute  the  extract with hexane and reanalyze.
      11.6  If the  measurement of  the  peak response is prevented
           by the  presence  of interferences, further cleanup is
           required.

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12.   CALCULATIONS
      12.1 Determine the concentration of carbon  disulfide in the
           sample.
           12.1.1 If the external standard calibration procedure
                  is used, calculate the amount of material injected
                  from the peak response using the calibration
                  curve or calibration factor  in  Section  7.2.2.
                  The concentration of dithiocarbamate in the
                  sample can be calculated as  follows:

                      Concentration, Ug/L  =
                    where:
                      A   = Amount of C$2  injected,  in  nanograms
                      V- =  Volume of extract injected  in yL.
                      Vt =  Volume of total extract  in  vl.
                      V  *  Volume of water extracted in mL.
                      M  »  Molecular weight of dithiocarbamate
                      C  =  Theoretical number of moles of CS?
                              formed per mole of dithiocarbamate.

       12.2 Determine the concentration of total dithiocarbamates in
            the sample as ziram.  When a specific dithiocarbamate is
            being measured, quantitate in terms of the  selected
            pesticide.
       12.3 Report results in micrograms per liter without correction
            for recovery data.  When duplicate and spiked samples are
            analyzed, report all data obtained with  the sample results.
       12.4 For samples processed as part of a set where the laboratory
            spiked sample recovery falls outside of  the control limits
            in Section 8.3, data for the affected compounds must be
            labeled as suspect.
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13.  METHOD PERFORMANCE
    13.1  The MDL 1s defined as the minimum concentration of a  substance
         that can be measured and reported with 99% confidence that the
                                                          t(
                                                          1
                    q
value is above zero.   The MDL concentrations listed in Table 1
         were obtained using spiked reagent water samples.
    13.2 This method has been tested for linearity of recovery from
         spiked reagent water and has been demonstrated to  be
         applicable over the concentration range from 10 yg/L to
         1000 yg/L.
    13.3 In a single laboratory, Battelle Columbus Laboratories,
         using spiked wastewater samples, the average recoveries
         of the parameters listed in Section 1.1 presented  in
         Table 2 were obtained.  Seven replicates of the wastewater
         were spiked and analyzed.  The standard deviation  of the
         percent recovery is also included in Table 2.
                                   45

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                               REFERENCES
1.  "Determination of Pesticides and Priority Pollutants in Industrial
    and Municipal Wastewaters," Report for EPA Contract 68-03-1760-
    Work Assignment 4 (In preparation).

2.  ASTM Annual Book of Standards, Part 31, D3694, "Standard
    Practice for Preparation of Sample Containers and for Preservation,"
    American Society for Testing and Materials, Philadelphia,
    PA, p. 679, 1980.

3.  "Carcinogens - Working with Carcinogens," Department of Health,
    Education, and Welfare, Public Health Service, Center for
    Disease Control, National Institute for Occupational Safety
    and Health, Publication No. 77-206, August, 1977.

4.  "OSHA Safety and Health Standards, General Industry," (29 CFR
    1910), Occupational Safety and Health Administration, OSHA 2206
    (Revised, January 1976).

5.  "Safety in Academic Chemistry Laboratories," American Chemical
    Society Publication, Committee on Chemical Safety, 3rd Edition,
    1979.

6.  "Handbook for Analytical Quality Control in Water and Wastewater
    Laboratories," EPA-600/4-79-019, U.S. Environmental Protection
    Agency, Environmental Monitoring and Support Laboratory -
    Cincinnati, Ohio 45268, March 1979.

7.  ASTM Annual Book of Standards, Part 31, D3370, "Standard
    Practice for Sampling Water," American Society for Testing
    and Materials, Philadelphia, PA, p. 76, 1980.

8.  Burke, J.A., "Gas Chromatography for Pesticide Residue Analysis;
    Some Practical Aspects," Journal of the Association of Official
    Analytical Chemists, 48, 1037 (1965).

9.  Glaser, J.A. et al, "Trace Analysis for Wastewaters", Environmental
    Science and Technology, 15, 1426 (1981).
                                 46

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     TABLE 1.   CHROMATOGRAPHIC CONDITIONS AND
               METHOD DETECTION LIMITS
Parameter
Amobam
Busan 40
Busan 45
EXD
Ferbam
KN-Methyl
Metham
Nabam
Nabonate
Na DMDTC
Thiram
Zineb
Ziram
Retention Time (Min)(a)
1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.3
MDL(ug/L)
1.1
4.4
1.3
5.2
2.9
2.7
3.1
1.6
0.9
2.8
2.2
4.1
4.6
(a)  Retention  time  of CS2  under the following  conditions:
     Carbopack  C (80/100  mesh)  coated with  0.1% SP-1000
     packed in  a 180 cm long x  2 mm ID glass  column with
     helium carrier  gas at  a flow rate of 25  mL/min.
     Column temperature held at 70°C for 3  minutes,
     programmed at 20°C/min to  120°C, and then  held at 120°C
     for 5 minutes.   Column effluent is vented  from the
     Hall  detector after  elution of C$2 from  the  column.
     Injector temperature and detector temperatures are
     200°C.  The Hall  detector  is operated  in the sulfur
     mode following  manufacturer's specifications.
                           47

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       TABLE 2.  SINGLE LABORATORY ACCURACY AND PRECISION
Parameter
Amobam
Busan 40
Busan 85
EXD
Ferbam
KN Methyl
Me than
Nabam
Nabonate
NaDMDTC
Th i ram
Zineb
Ziram
(a) 1 -
Sample
Type(a)
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Wastewater
Background
ug/L
4.6
4.6
6.6
6.6
5.9
5.9
4.5
4.5
5.2
5.2 '
5.4
5.4
6.2
6.2
4.8
4.8
6.1
6.1
5.4
5.4
4.5
4.5
5.2
5.2
5.7
5.7
Spike Mean
vg/L Recovery, %
50
500
50
500
50
500
50
500
50
• 500
50
500
50
500
50
500
50
500
50
500
50
500
50
500
50
500
from a manufacturer of a
90
93
110
100
110
100
71
76
94
no
90
89
no
84
62
65
66
56
no
no
89
82
87
86
100
95
Standard
Deviation
7.8
8.7
7.2
6.1
5.5
2.0
7.5
2.4
4.8
1.8
6.1
2.5
5.2
5.9
6.6
13
11
12
2.5
4.2
2.9
3.4
3.4
9.4
12
19
dithiocarbamate diluted
Number of
Replicates
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
1000:1
with Columbus POTW secondary effluent.
                            48

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                        cs,
1.10      1.20     1.30      1.40      1.50      1.60     1.70     1.80     1.90    2.00




                         Retention Time,  Min.
  FIGURE 1.  GC-HALL CHROMATOGRAM OF 0.1  NG OF C$2

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