OSEPA/PAPER INDUSTRY COOPERATIVE DIOXIN STUDY
            "The 104 Mill Study"
               SUMMARY REPORT
                  July 1990
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
  Office of Water Regulations and Standards
              401 M Street,  S.W.
           Washington/  D.c.    20460

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          USEPA/PAPER INDUSTRY COOPERATIVE DIOXIN STUDY
                      "The  104 Mill Study"
                          SUMMARY REPORT
                        Table of Contents


                                                            Page

A.  Introduction                                              1

B.  Principal Findings and Conclusions                        2

C.  Study Features                                            5

    1. Mills Included in the 104 Mill Study                   5
    2. Field Sampling Program                                 5
    3. Analytical Program                                     6
    4. Data Handling                                          7

D.  Industry Profile                                          8

    1. Pulping and Bleaching                                  8
    2. Bleach Line Chemical Usage                             9
    3. Wastewater Treatment                                  11

E.  Summary of Results                                       12

    1. Bleached Pulps                                        13
    2. Wastewater Effluents and Wastewater Sludges           14
    3. Mass Flows Of 2378-TCDD/TCDF                          16
    4. Bleaching Practice and Formation of                   18
       2378-TCDD/TCDF in Kraft Mills
    5. Kraft Mill Wastewater Treatment Findings              20
    6. Other 2378-Substituted CDDs and CDFs                  22

References                                                   27

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          U8EPA/PAPER INDUSTRY COOPERATIVE DIOXIN STUDY
                      »Th«  104 Mill Study"

                         SUMMARY REPORT

A.   Introduction

     In October of  1987  the U.S.  Environmental Protection Agency
(EPA)  and the  U.S.  pulp   and  paper  industry jointly  released
preliminary results from a screening study that provided the first
comprehensive  data  on   formation  and discharge  of  chlorinated
dibenzo-p-dioxins  (CDDs) and dibenzofurans (CDFs)  from  pulp and
paper mills (1) .  This early screening study of  five bleached kraft
mills ("Five Mill Study") confirmed that the pulp bleaching process
was primarily responsible for the formation of the CDDs and CDFs.
The  study  results  showed that 2378-TCDD was present  in  seven of
nine bleached pulps, five of five wastewater treatment sludges, and
three of five treated wastewater effluents.  The study results also
indicated that 2,3,7,8-tetrachlorodibenzo-p-dioxin (2378-TCDD) and
2,3,7,8-tetrachlorodibenzofuran (2378-TCDF) were the principal CDDs
and CDFs formed.  The partitioning of these compounds between the
bleached pulp, wastewater treatment  sludge,  and  final wastewater
effluent was found to be  highly variable among the  five mills.  The
final Five Mill Study report was published in March 1988 (2).

     To provide the EPA with more complete data on the release of
these compounds by the U.S.  industry, an agreement was reached in
April 1988 between EPA and the industry to conduct a second study
to characterize the 104 U.S. mills that practice chlorine bleaching
of  chemically produced  pulps  (3) .   The  scope of  the  study was
developed  by  EPA  and industry,  and the study  was managed by the
National  Council  of  the  Paper   Industry for   Air  and  Stream
Improvement, Inc.,  (NCASI),  with EPA overview.  The  data  from this
study provide an estimate of the release of 2378-TCDD and 2378-TCDF
in  three  environmental  export vectors (bleached pulp, wastewater
sludge,  and wastewater  effluent)  from the U.S.  pulp  and paper
industry as of mid to late  1988.

     This  summary report presents the major features of the study
design, sample collection,  and analytical methodologies;  a profile
of  the  industry at the time the study was conducted  in terms of
number and types of mills, number and types of bleach lines, bleach
line  operating characteristics during sampling,  and wastewater
treatment;  and  the study results. This report and a statistical
analysis of the data from the study were prepared  independently by
USEPA  (4).   The paper industry,  through NCASI, has also prepared
a report of the 104  Mill  Study (5) .  Preliminary study results were
presented  by NCASI  and  EPA in September  1989 (6) ,  and will be
published  in Chemosphere.   This  report  includes  analytical data
received by  EPA from NCASI  as of April 1990.   These data comprise
virtually  all  of  the   analytical  data  required  by the study
objectives.

     When  reviewing the  study results, it  is  important to  keep in
mind the  principal  objective of the  104  Mill  Study  was  to

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characterize exports from the 104 mills in terms of 2378-TCDD and
2378-TCDF.  The  study  was not designed to address  mechanisms of
formation of  these  compounds or to  determine what are  the  best
technologies for minimizing formation or treating these compounds
in wastewaters.  Nonetheless,  the study results permit some useful
observations in these areas.

     The terms used in this report to describe CDDs and CDFs, and
pulping, bleaching and wastewater treatment in the pulp and paper
industry are defined in the glossary  for the Five Mill Study  (2).


B.  Principal Findings and Conclusions

    Industry Profile

    1.  At the time the 104 Mill Study field program was underway
(mid to late 1988 for most mills), the U.S. pulp and paper industry
was characterized by only limited application  of those pulping and
bleaching  technologies and  operating practices  that have  been
demonstrated to  have  the potential to reduce formation  of 2378-
TCDD/TCDF.    Since  that  time,  many  mill  operators  have  been
implementing programs  designed to improve pulping  and bleaching
technologies and operating practices.

    Data Summary

    2.    Analyses  of  field  and  laboratory duplicate  samples
indicated excellent  agreement.   Consequently, the  proportion of
total variability in 2378-TCDD/TCDF concentrations which could be
attributed to variability in field sampling,  or sample handling and
analytical  techniques,  was in all cases small  relative  to other
sources  of variability,  which are  generally attributed  to the
process.

    3.  The analytical techniques used are suitable for low-level
determinations of 2378-TCDD and 2378-TCDF in  kraft mill effluents
(i.e., at or below 0.010 ng/kg, or 10 ppq); and, for determinations
of 2378-TCDD and 2378-TCDF in bleached pulps and wastewater sludges
in the  range  of  1 ng/kg (or 1 ppt).   Target  analytical detection
levels  were achieved  or exceeded for most samples and valid data
were obtained  for nearly all  samples.

    4.   2378-TCDD  and 2378-TCDF were  detected  in  samples  from
bleached kraft and bleached sulfite mills as  follows:

                           Kraft Mills    Sulfite Mills

            2378-TCDD         90 %            56  %
            2378-TCDF         97 %            85  %

        No  mill  was found  to  be  free  of 2378-TCDD/TCDF.

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    5.   Detected  concentrations of 2378-TCDD and  2378-TCDF  were
best approximated  by lognormal distributions for  each of the export
vectors: bleached pulp, wastewater sludge and wastewater effluent.

    6.  The data on concentrations of 2378-TCDD and 2378-TCDF found
in the export matrices are summarized below.  The number of samples
with non-detect analyses  (ND's) are listed  for  each matrix.   The
mean, median,  90th percentile and maximum values  are  based  upon
samples  with detected  concentrations of 2378-TCDD or  2378-TCDF.
Non-detect results were not included in the statistics.

                                     (results in no/kg. or ppt)
                Number of Samples
                 Detects   ND's    Mean   Median   90%  Maximum

Bleached Pulps
  Kraft Hardwood
   2378-TCDD        62     12       7.5    4.0     17       56
   2378-TCDF        72      2      56     17      107      661

  Kraft Softwood
   2378-TCDD        98      6      12      7.6     27      116
   2378-TCDF        99      3     118     26      185     2620

  Sulfite Hardwood
   2378-TCDD         3      5       7.1    4.4     15       15
   2378-TCDF         5      3      73      9.9    323      323

  Sulfite Softwood
   2378-TCDD         1      7       3.5    3.5      3.5     3.5
   2378-TCDF         7      2     125      6.3    449      449
Wastewater Effluents
  Kraft Mills
   2378-TCDD        90     17
   2378-TCDF       104      7

  Sulfite Mills
   2378-TCDD        12     13
   2378-TCDF        21      4
        0.076
        0.48
        0.013
        0.11
         0.035
         0.10
         0.012
         0.035
           0.19
           1.1
           0.023
           0.38
           0.64
           8.4
           0.023
           0.84
Wastewater Sludges
  Kraft Mills
   2378-TCDD        94
   2378-TCDF        97

  Sulfite Mills
   2378-TCDD        18
   2378-TCDF        16
3
0
1
0
101
796
 13
 99
 39
161
  4.7
 63
 203
1728
  48
 350
 1390
17100
   58
  584

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     Partitioning of 2378-TCDD/TCDF

    7.   The partitioning  of 2378-TCDD  and  2378-TCDF to  export
vectors within  mills  was found to  be highly consistent at  most
kraft mills.

    8.   The partitioning  of 2378-TCDD  and  2378-TCDF to  export
vectors was highly variable  between mills.   For all kraft  mills,
about  38  % of  the  2378-TCDD was partitioned to pulps,  33  %  to
wastewater sludges and 29 % to wastewater effluents.

    9.  The estimated annualized mass output rates of 2378-TCDD and
2378-TCDF  for the kraft  and  sulfite  segment  of  the U.S.  industry
at the time of the study were estimated at 1.46 Ibs (0.66 kg) and
11.7 Ibs  (5.31 kg),  respectively.

     Bleach Plant Practice and Formation of 2378-TCDD/TCDF

    10.  The formation rates  of  2378-TCDD and 2378-TCDF are likely
to be somewhat higher than the output rates cited above since the
amounts  of these compounds  that  may  be partitioned  to  settled
sludges in aerated stabilization basins was not quantified in the
sampling program.

    11.  Correlations between mass export rates of 2378-TCDD/TCDF
and a  series of kraft  mill  operating parameters  were generally
poor.   However, positive  trends were observed between  average
formation  of 2378-TCDD/TCDF and application of chlorine in the C-
Stage  and  with chlorine  multiple  (Kappa  factor).    Increased
application of chlorine generally resulted in increased formation
of  2378-TCDD/TCDF.    Increased  substitution  of  chlorine  dioxide
generally  resulted in decreased formation of 2378-TCDD/TCDF.

     Wastewater Treatment

    12.    On average,  mills  with  activated   sludge  wastewater
treatment  systems  exported  less  2378-TCDD/TCDF  to  wastewater
effluents  and more  to wastewater  sludges than  mills with aerated
stabilization basin treatment.

    13.  Correlations between Total Suspended  Solids concentrations
and  2378-TCDD/TCDF  mass  outputs  for  kraft   mills  were  weak,
suggesting that TSS levels were at best  only partially predictive
of  2378-TCDD/TCDF  levels  in wastewater effluent  and wastewater
sludge.

     2378-Substituted CDDs and CDFs

    14.    In  addition  to  2378-TCDD and  2378-TCDF,  the  most
frequently occurring  2378-substituted  CDDs and  CDFs found in mill
exports  from nine of  the 104 mills included 1234678-HpCDD, OCDD,
12378- and 23478-PeCDF and OCDF.

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    15.  When  considered  in terms of both the EPA  and  the I-TEF
toxic equivalency approaches, 2378-TCDD and 2378-TCDF account for
the vast majority of the computed  2378-TCDD equivalent toxicity in
each mill export.   Accordingly, current  U.S.  regulatory programs
that are focused on  these compounds appear to be properly directed.


C.  Study Features

     1.  Mills included in the 104 Mill Study

     All U.S. pulp and paper mills where chemically produced wood
pulps  are  bleached with  chlorine and chlorine  derivatives were
included in the Agreement  for the 104 Mill Study  (3) .  However, six
bleached kraft mills were not sampled as  part of the study.  These
included the five mills  sampled for the  Five Mill  Study and the
Consolidated Papers mill  located  at Wisconsin Rapids,  Wisconsin.
Consolidated Papers had  independently conducted a study  at the
Wisconsin Rapids  mill.  Although  mills  included  in the Five Mill
Study were not  resampled in the 104 Mill Study, 2378-TCDD/TCDF data
and mill operating  and wastewater treatment  information from the
Five Mill  Study  have  been  included in  this  analysis.    Due to
differences in sampling and analytical protocols, the Consolidated
Papers data  for  2378-TCDD/TCDF  were not  included.   However, mill
operating  and  wastewater treatment  information  for Consolidated
Papers were included in the industry profiles presented in Section
D.

     2.  Field Sampling Program

     The Agreement  required that  each significant  export vector
(fully bleached pulp, wastewater sludge,  final wastewater effluent)
be sampled and the  samples composited over a five day period  (3).
In most cases the composite  samples were  comprised of up to eight
aliquots obtained throughout the sampling day.  Nearly all sampling
was performed by mill personnel following guidance established by
NCASI.   In a few cases,  NCASI  personnel conducted the sampling.
The sampling protocols closely  followed those established for the
Five Mill Study  (2).

     The  pulp  samples taken were representative of  the highest
brightness pulp  produced  at each bleach  line.   Hence,  at a mill
with  two  bleach lines,   where  hardwood  and  softwood  pulps are
bleached separately, separate hardwood and softwood  composite pulp
samples were collected.  At a mill with a single  bleach line where
both hardwood and softwood pulps are bleached (i.e.,  a swing line),
sampling  was  conducted   intermittently  to ensure  the  five day
composite samples were composed of only hardwood  or  softwood pulp.
At  a limited  number of  mills  hardwood/softwood brownstock pulp
mixtures are bleached.  Bleached pulp from those lines were  sampled
as noted above  for  single bleach  lines.

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     Sludge samples consisted of only  those  sludges removed from
the wastewater treatment system and disposed of  in landfills,  by
incineration, or by other methods.  Thus, for mills with activated
sludge wastewater treatment systems, the sludges sampled generally
consisted of combined primary and secondary sludge; for mills with
aerated stabilization basins, only primary sludges were sampled.
Although in most cases the  sludges sampled were dewatered prior to
offsite disposal, several primary sludges were collected in a low
consistency slurry form.

     More than 90 effluents sampled were collected  from mills with
biological treatment.   For eight mills,  the  samples consisted of
partially  treated  effluents prior  to  discharge to  municipal
wastewater treatment plants.  Untreated  effluents  from two mills
with direct ocean discharges were sampled.  An untreated effluent
from a mill  with a percolation pond for  wastewater disposal was
also sampled.

     This sampling  scheme  generated over 400 samples for isomer-
specific 2378-TCDD  and  2378-TCDF analyses.   About 80 additional
samples were  collected  as part of the quality assurance/quality
control plan.   These samples were  analyzed  as  field duplicates
and/or included  in  native  spike  determinations.   Samples of each
export vector from 9 mills were analyzed for all 2378-substituted
CDDs and CDFs. The nine mills were chosen by NCASI to represent a
variety of bleaching and wastewater treatment configurations.

     In  addition to  the  physical samples,  mill  operators were
required to  provide process operating data  for  bleacheries and
wastewater treatment plants. These data were  collected to document
operation of the processes at the time of sampling.

     3.  Analytical Program

     The Brehm Laboratory at Wright State University (WSU) , Dayton,
Ohio, performed analytical methods development  work for isomer-
specific determinations of  2378-TCDD  and 2378-TCDF  in pulp and
paper mill matrices, and completed analyses of all  samples for the
Five Mill Study  (2).  Analytical  work  for this study was conducted
by  Enseco-California   Analytical   Laboratories    (CAL)   in  West
Sacramento, California, and WSU.  Enseco-CAL analyzed most  of the
sludge and effluent samples, while WSU analyzed most of the pulp
samples.

     The  analytical  methods used  in  the  104  Mill  Study were
consistent with  the screening study protocols  established for the
"Five Mill Study" (2).  Analytical objectives for target detection
limits for  2378-TCDD and 2378-TCDF  were 1 ng/kg(ppt) for sludges
and  pulps,  and  0.01 ng/kg(ppt)  for  wastewater effluents.   The
Agreement specified identification  and quantitation criteria for
2378-TCDD/TCDF    and    required   that  NCASI   manage  quality

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assurance/quality control  programs for the  study.    NCASI  staff
performed and coordinated  sample  preparation,  submitting samples
to  the analytical  laboratories,   and  reviewing laboratory  data
reports.     Nearly   all  analytical  results   met   the  quality
assurance/quality control  objectives  established for the study.
Less  than six  percent  of the  samples  required  more  than  one
analysis  to  obtain  valid data.   This was  judged by  EPA to  be a
reasonably small proportion given the study objectives for minimum
detection levels  and the complexity of the  analyses  in terms of
sample  extraction   and  analyte  recovery,   identification  and
quantitation.

     4.   Data Handling

     To ensure consistent reporting of bleach plant and wastewater
treatment information,  NCASI  developed specific forms for use by
mill personnel  to report  bleach  line  operating characteristics,
bleach  line chemical   applications   and   wastewater   treatment
operations.  Copies  of  these  forms, as well as schematic diagrams
of  the bleacheries  and wastewater treatment  facilities,  were
provided  to  EPA by NCASI for  most mills.   For those few  mills for
which  confidential  treatment  of certain  data were requested, the
forms  were  submitted directly  to EPA  by mill  operators.   NCASI
submitted final analytical results to EPA as they were developed,
in conformance with  the  quality assurance/quality control  protocols
specified in the Agreement.

     EPA  and NCASI  independently developed  data  summaries in
spreadsheet   format  to  characterize   bleach   line   operating
characteristics;  mass  flow  rates  of  bleached  pulp, wastewater
sludge  and wastewater effluent; and, mass  flows of 2378-TCDD and
2378-TCDF in the mill exports.  The respective  spreadsheet entries
were   compared   several  times  and  corrections  were  made  as
appropriate.  Prior to conducting detailed statistical  analyses,
EPA had a contractor further  compare the EPA spreadsheets against
the original report forms.  All  discrepancies were resolved and the
spreadsheets were updated accordingly.   New databases  were  then
created by uploading the  data from the spreadsheets to the EPA
mainframe computer.

     As data were received from NCASI,  the  Industrial Technology
Division  compiled summaries of bleached pulp, wastewater sludge and
wastewater effluent concentrations and distributed the  results to
EPA  regional offices  and state  agencies.   On  May  4,   1989, EPA
determined that certain bleach plant process data supplied by mill
operators should be provided  confidential treatment,  but  that
bleached  pulp  data  for 2378-TCDD/TCDF  and  other  miscellaneous
bleach plant data   were  not  confidential.    The  data  summaries
presented in this report do not disclose  confidential bleach  plant
data.

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                                                                8
D.   Industry Profile

     1.  Pulping and Bleaching

     Tables 1 and 2 present the profiles for pulping and bleaching,
respectively, for those mills included  in the study.  This segment
of the U.S.  industry is comprised of 86 kraft  pulping mills,  16
sulfite mills,  one soda mill  and one  mill  with both  kraft  and
sulfite pulping. More than half of the  bleach lines at kraft mills
are used for bleaching softwoods exclusively and forty percent for
bleaching hardwoods.   The  balance are either swing  lines  or  are
used to bleach hardwood/softwood pulp mixtures.   For sulfite mills,
half the bleach  lines are used for bleaching softwood pulps, nearly
40% for hardwood pulps and the balance for mixed pulps.
     Table 1:  Industry Profile - Pulping

                                        Number of Mills

               Kraft                            86
               Sulfite                          16
               Kraft and Sulfite                 1
               Soda                              1

                              Total            104
     Table 2:  Industry Profile - Bleaching

                                    Number of Bleach Lines

                                   Kraft    Sulfite   Soda
           Hardwood                  67         7       1
           Softwood                  89         9
           Mixed HW/SW                9         2       -

                         Total      165        18       1

          Note:  (1) Kraft  hardwood  and  softwood bleach line data
                    include  14  swing  lines.   Each swing line was
                    counted as both a hardwood and a softwood line,
                    where  appropriate;   or,  as  two  hardwood  or
                    softwood  lines  where multiple  grades  of the
                    same species were bleached.

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     2.  Bleach Line Chemical Usage

     Table 3 presents  a summary of the number  and  percentage of
bleach lines with oxygen delignification systems and chemical use
in pre-bleaching and final bleaching.   The  data were provided by
mill  operators to  characterize operations  during  the  sampling
surveys.
     Table 3:  Industry Profile - Bleach Line Chemical Usage

                                  Number of Bleach Lines,(%)

                                  Kraft and Soda      Sulfite

          Oxygen Delignification      7 (4.2)        1 ( 5.6)

          Pre-bleaching
           Chlorine Stage C12       166 (100)       16 (89)
           Chlorine Stage C102      106 (64)        1 ( 5.6)

           Extraction Stage 02       79 ( 48)        4 (22)
           Extraction Stage NaOCl    47(28)        1(5.6)
           Extraction Stage H202      2(  1.2)      1(5.6)

          Final Bleaching
             C102                   148 (89)        4 (22)
             NaOCl                   90 ( 54)       14 (78)
             H202                    25 (15)        1 ( 5.6)


     As  shown  above,  the  industry was characterized  by low
utilization of oxygen delignification, relatively low utilization
of  oxygen  reinforced extraction,  low  utilization  of  peroxide
reinforced   extraction,   and  relatively  high  utilization  of
hypochlorite in both pre-bleaching and final bleaching.

     The status of bleachery operations of the U.S.  industry in mid
to late 1988 with respect to chlorine usage and chlorine  dioxide
substitution is summarized in Table 4.  Note that about 35 % of the
kraft mill bleach  lines were  operated with no  chlorine dioxide in
the  Chlorine Stage  (C-Stage) ,  and  less than 2 %  had chlorine
dioxide substitution  rates greater than  50  %, a level which has
been  demonstrated  to have   significant  positive  effects for
minimizing formation of several chlorinated organic compounds, and
2378-TCDD/TCDF in  particular  (7).

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                                                               10
     Table 4:   Status of U.S.  Bleachery Operations
               C-Staoe Chlorination and Chlorine Dioxide
               Substitution (1988)
     Chlorine Application
Ibs C12/ton ADBSP   Bleach Lines
                              C102 Substitution
                           percent      Bleach Lines
     < 40 Ibs/ton
    40-60
    60-80
    80-100
   100-120
   120-140
     > 140

        TOTAL
     < 40 Ibs/ton
    40-60
    60-80
    80-100
   100-120
   120-140
     > 140
                     Kraft Mill Bleach Lines
            15
            22
            32
            36
            28
            16
            16

           165
      0 %
    < 5
 5-10
10 - 20
20 - 30
30 - 40
40 - 50
50 - 60
60 - 70
   > 70
                    Sulfite Mill Bleach Lines
             TOTAL
             2
             1
             2
             6
             3
             4
             0

            18
      0 %
    < 5
    > 5
                                                TOTAL
          TOTAL
 59
 16
 41
 33
  9
  1
  3
  1
  1
  1

165
 17
  1
  0

 18
Notes: (1)

       (2)
Bleachery operations for swing lines were counted
separately for hardwood and softwood pulps.
ADBSP - Air-dried brownstock pulp.
     Table 5 presents a summary of 5 day average chlorine multiples
(Kappa factor)  determined for kraft and sulfite bleach lines at the
time of sampling.  The chlorine multiple is the ratio  of the amount
of active chlorine used  in  pulp  bleaching in the C-Stage,  to the
amount of lignin contained in brownstock or oxygen delignified pulp
as characterized  by  the Kappa number.   At the  time of  the mill
sampling programs, 11 per cent of bleach lines were operated with
average chlorine multiples less than 0.15, a level which has been
cited as  a  threshold below which  formation  of  2378-TCDD/TCDF is
greatly  reduced  (7) .    The average  chlorine  multiple  over  an
extended period may  not  be  a good measure of the 2378-TCDD/TCDF-
forming potential of a pre-bleaching  operation  since  short term
variations above 0.15 are thought to be significant.

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                                                               11
<
0.10 - <
0.15 - <
0.20 - <
0.25 - <
: 0.10
: 0.15
: 0.20
: 0.25
: 0.30
     Table 5:   C-Staae Chlorine Multiple (Kappa Factor)

                                     Number of Bleach Lines
     Chlorine Multiple                Kraft       Sulfite

                                        4            2
                                       15            1
                                       51            6
                                       54            3
                                       17
            > 0.30                     14            6

                         Total        155           18

    Notes:  (1)  Chlorine multiple was computed from active
                 chlorine (C12 and C102) applied in the C-Stage.
            (2)  Chlorine multiples could not be computed for
                 ten kraft mill bleach lines because of
                 incomplete data.


     On balance,  pulping and bleaching facilities were not operated
to minimize formation of 2378-TCDD/TCDF at the time of the 104 Mill
Study.  Presently, there are several bleachery upgrades underway,
many of which include partial extended delignification, increasing
capability  for  chlorine  dioxide  substitution,  modification  of
caustic   extraction   systems   and   installation   of   oxygen
delignification systems.

     3.  Wastewater Treatment

     The status of wastewater treatment provided at the 104 mills
is  summarized in  Table  6.    The industry  standard  is  primary
treatment followed by secondary biological  treatment.  Eight mills
discharge  to  POTWs  after  primary  treatment  and  two  have  no
treatment.    Wastewaters  from  one  mill  are  disposed  of  in  a
percolation pond.  For the kraft segment, about 35 % of the mills
have activated sludge treatment and more  than half have aerated
stabilization  basins.    For  sulfite  mills,  nearly  70   %  have
activated sludge systems and nearly 20 % have  aerated  stabilization
basins.

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                                                               12
     Table 6:  Industry Profile - Wastewater Treatment

                                         Number of Mills

                                   Kraft   Sulfite   Soda   Total

Activated Sludge                     32      11        -     43
Aerated Stabilization Basin          45       3        1     49
Discharge to POTW                     71               8
Discharge to Other Mill WWTP          -       1        -      1
Percolation Pond                      1       -               l
No Treatment                          2       -        -      2

                    Total            87      16        1    104

       Note: (1)  The mill with kraft and sulfite pulping was
                  listed as a kraft mill for purposes of this
                  table.


E.   Summary of Results

     Examination of analytical data from samples collected at each
mill indicated detected concentrations of 2378-TCDD/TCDF were best
approximated by lognormal distributions, estimated separately for
each of the export matrices:  bleached pulp,  sludge, and effluent.

     Estimates of non-detected measurements were required for the
analyses  of results.    For  the  purposes   of  this  study,  these
measurements were  assigned a  value equal  to  half  the detection
limit.  This compromise procedure has been used in other studies
and enables information from non-detect samples to be utilized (4) .
This procedure was  judged  reasonable in light of the significant
proportion of all samples with detectable concentrations of 2378-
TCDD/TCDF, and the consistent partitioning of 2378-TCDD and 2378-
TCDF within mills.  In  this study,  and  in the Five Mill Study, no
mill was found to be free of 2378-TCDD/TCDF.

     About  30%  of all  the samples  analyzed were field duplicate
samples or laboratory-split duplicate samples.  Analysis of these
duplicate samples indicated that within  each matrix  (pulp, sludge
and  effluent),  excellent  agreement  was shown  between repeated
measurements of 2378-TCDD/TCDF concentration.   Most correlations
between pairs of  duplicate measurements were found to be greater
than 0.95.   Consequently,  the proportion of total variability in
2378-TCDD/TCDF levels which could be  attributed to variability in
field  sampling protocol or analytical technique was in all cases
small relative to  other sources of variability, which are generally
attributed  to the  pulping  and bleaching processes.  This finding

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                                                               13

supports  averaging of  duplicate pair  results  for purposes  of
estimating mass flow rates of 2378-TCDD/TCDF,  as was done in this
study.

     The  analytical  techniques used  are suitable  for  low-level
determinations (i.e., in the range of and  below 0.010  ng/kg, (10
ppq))i   of 2378-TCDD/TCDF  in  kraft mill  wastewater  effluents.
Analysis  of sulfite  mill  effluents  may not be  as  precise over a
larger  range.   The  study results  also indicate  the  analytical
methods are suitable  for determinations of 2378-TCDD/TCDF in the
range of 1 ng/kg  (1 ppt) for bleached pulps  and wastewater sludges.

     1.  Bleached Pulps

     Summary statistics of  2378-TCDD/TCDF concentrations expressed
as ng/kg(ppt)  in the bleached pulps are  presented in Table 7.  The
data are  reported by  pulping type  (kraft and  sulfite)  as well as
by wood  specie  (hardwood  and softwood).   The  statistics include
number of samples with non-detect results,  number of samples with
detectable results, and mean, median,  90th percentile and maximum
concentrations.  Non-detect  analytical  results were not included
for calculation of mean, median and 90th  percentile concentrations.
       Table 7: 2378-TCDD/TCDF Concentrations in Bleached Pulps
                Number of
                 Samples
                ND  Detect
 HW Kraft Pulps
  2378-TCDD    12
  2378-TCDF     2

 SW Kraft Pulps
  2378-TCDD     6
  2378-TCDF     3

 HW Sulfite Pulps
  2378-TCDD     5
  2378-TCDF     3

 SW Sulfite Pulps
  2378-TCDD     7
  2378-TCDF     2
62
72
98
99
 3
 5
 1
 7
        Mean
       fnq/ka)
  7.5
 56
 12
118
  7.1
 73
  3.5
125
        Median
        fnq/kg)
 4.0
17
 7.6
26
 4.4
 9.9
 3.5
 6.3
       90 %
      fna/kcn
 17
107
 27
185
 15
323
  3.5
449
       Maximum
       fna/kq)
  56
 661
 116
2620
  15
 323
   3.5
 449
     Note that these  findings are representative of the  104 mills
as  of  mid  to late 1988 when most  of the sampling was completed.

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                                                               14

Since that  time several  mill operators  have been  implementing
process changes designed  to  reduce  2378-TCDD/TCDF concentrations
in bleached pulps.   Although the net effect of  these  changes on
formation of 2378-TCDD/TCDF  is  not  fully known  or  quantified at
this time,  examination of preliminary  results supplied by  mill
operators indicate  significant  reductions in  formation  of 2378-
TCDD/TCDF may be possible.

     Correlating the  above pulp  findings with pulping or  bleach
plant process parameters  was  significantly  limited  because 2378-
TCDD/TCDF concentrations in bleached pulp  represent only a portion
of that formed in the bleach  plant.  The "Five Mill Study" clearly
demonstrated that bleach plant filtrates represented a significant
fraction  of the total mass  of  2378-TCDD/TCDF  formed, and  the
distribution  between  the pulp  and filtrate  phases  was  highly
variable from mill  to  mill (1,2).   That finding  was confirmed by
the more  extensive data  obtained from  this study,  (see Section
D.3).   Hence,  correlations  of bleach plant  operations with  only
pulp data would not be valid and are not  presented. Because it was
not the objective of this study to fully investigate the impact of
pulping  and  bleaching  process parameters  on  2378-TCDD/TCDF
formation in the bleach plant, filtrate samples were not collected.

     2.  Wastewater Effluents and Wastewater Sludges

     Tables 8 and  9 present  summary statistics of 2378-TCDD/TCDF
concentrations  in wastewater effluents and sludges, respectively.
The summary statistics are the same as those  presented for bleached
pulps  in  Table 7.    Data for kraft mills and sulfite mills are
distinguished.  Samples of wastewater sludge slurries  obtained at
a number of mills (generally  less than 5%  solids)  were  analyzed as
liquids.  Although  these  data were  not  included  in Table 9,  they
were considered in mass flow calculations for the respective
mills.
  Table 8:  2378-TCDD/TCDF Concentrations in Wastewater Effluents

                 Number of
                  Samples       Mean    Median   90 %    Maximum
                 ND  Detect     (ng/kg)   (na/ka)  fna/ka)   (na/kg)

  Kraft Mills
   2378-TCDD     17    90       0.076    0.035     0.19    0.64
   2378-TCDF      7    104       0.48     0.10      1.1     8.4

  Sulfite Mills
   2378-TCDD     13    12       0.013    0.012     0.023   0.023
   2378-TCDF      4    21       0.11     0.035     0.38    0.84

   Note:  (1)  A  few mills have  more than one wastewater effluent.
              All available effluent  data are  included.

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                                                                15
   Table 9:  2378-TCDD/TCDF Concentrations  in Wastewater Sludges
                 Number of
                  Samples
                 ND  Detect
  Kraft Mills
   2378-TCDD
   2378-TCDF

  Sulfite Mills
   2378-TCDD
   2378-TCDF
3
0
1
0
94
97
18
16
             Mean
            (nq/kq)
101
796
 13
 99
                Median   90 %
                fnq/kg) fnq/kq)
  39
 161
 4.7
63
 203
1728
  48
 350
                         Maximum
                         (nq/kg)
 1,390
17,100
    58
   584
Note: (1)  Analytical results  for dewatered  sludges are included;
           results for sludge  slurries are not  included.


     The effluent  and sludge concentrations measured  for sulfite
mills were generally  less than those for kraft mills,  as was the
case for bleached pulps described in Table 7.  In all exports, the
concentrations of 2378-TCDD/TCDF were found  to  be highly variable
and distributed  lognormally.   Figure 1 presents  the distribution
of 2378-TCDD in wastewater effluents.  Distributions of 2378-TCDD
and 2378-TCDF were similar for all  exports.
                             Figure 1

                          EFFLUENT TCDD
                 PROBABILITY PLOT: DETECTED VALUES ONLY
              o
              3
              N
              o
              c
              00
              o
-1
                   -2
                   -3
                             10        100       1000
                          TCDD Concentration in PPQ

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                                                               16
     3.   Mass Flows of 2378-TCDD/TCDF

     Rates  of 2378-TCDD/TCDF  mass flow  were  computed for  all
matrices at each mill by combining the 2378-TCDD/TCDF concentration
data with  mill production  rates of  pulp,  sludge and  effluent.
Estimates of mass output rates of 2378-TCDD and 2378-TCDF at U.S.
bleached pulp mills were 1.46 Ibs/yr (0.66 kg/yr)  and 11.7 Ibs/yr
(5.31 kg/yr),  respectively.  Output rates varied substantially from
mill to  mill.   Comparisons showed that significantly more 2378-
TCDD/TCDF was exported at kraft mills than at sulfite mills.

     The summary statistics of total mill exports of 2378-TCDD/TCDF
from kraft and sulfite mills are highlighted  in Table  10.   These
results are presented in terms of Ibs/ton of air-dried brownstock
pulp (ADBSP) and include data from only those mills with complete
mass  flow  data  for  pulp,  sludge,  and  effluent  and  complete
analytical data for 2378-TCDD/TCDF.

     Note that calculated total mill mass flow rates for mills with
aerated  stabilization basins  may not fully reflect  the rates of
formation  of  2378-TCDD/TCDF.    The results  for those  mills are
probably biased low due  to  retention  of 2378-TCDD/TCDF in sludge
in aerated lagoons which would not have been characterized by the
sampling program.  Accordingly,  the results presented are believed
to be  representative  of total mill exports for all  mills at the
time of sampling, but not necessarily fully representative of the
total amount of 2378-TCDD/TCDF formed.
      Table 10:  Total Mill Exports of 2378-TCDD/TCDF

                                (Results in 10-8 Ibs/ton ADBSP)
  Kraft Mills
   2378-TCDD
   2378-TCDF

  Sulfite Mills
   2378-TCDD
   2378-TCDF
                     Number of
                       Mills
80
80
14
14
       Mean   Median   90 %  Maximum
 4.9
48
 1.0
14
 2.8
10
 0.46
 3.5
 12
123
  3.3
 73
 31
954
  4.5
145
    Notes:  (1) Only results for mills with complete analytical and
               mass flow data are  included.

            (2) Mass   flow  calculations   for  several  mills  are
               affected    by    sludge   retention   in   aerated
               stabilization basins.
            (3) ADBSP  - Air-Dried Brownstock Pulp

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                                                               17
      Figure 2  illustrates the distribution of estimated mass flows
 of 2378-TCDD among pulp, effluent and sludge for kraft and sulfite
 mills on an industry-wide basis.
                              Figure  2
                   TOTAL  OUTPUT: TCDD
             KRAFT MILLS
                        PULP
EFFLUENT
                                             SULFITE MILLS
                                                              PULP
                                   EFFLUENT
                         SLUDGE
                                                        SLUDGE
      The high variability  of  the  partitioning  of 2378-TCDD among
 exports on a mill  to  mill  basis is  highlighted in Figure  3.   The
 results for 2378-TCDF were similar.   Each boxplot shown in Figure
 3 was  constructed  such that the top and bottom  edges  of  the box
 represent  the  upper and lower  quartiles of the  distribution of
 percentages taken across all mills.  The  line dividing each box is
 the  median,  and the  middle  95% of all  data  is  depicted  by the
 extensions above and below each box.

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                                                              18
                            Figure 3


                    % OUTPUT  BY MATRIX

                              TCDD
          Q
          Q
           3
           a
               100
                80
                60
                40
                20
                               Matrix
     As was the case with the Five Mill Study results,  within-mill
partitioning of 2378-TCDD among mill exports compared to  that of
2378-TCDF  was  found to  be consistent.    Although  statistical
analyses were not conducted to fully examine this phenomenon,  the
maximum difference between partitioning of 2378-TCDD and 2378-TCDF
among pulp, sludge  and effluent at  80 % of  kraft mills was found
to be less than 20 %.

     4.   Bleaching Practice and Formation of 2378-TCDD/TCDF
          in Kraft Mills

     Analyses were completed on the  effects of mill bleaching
procedures upon formation of 2378-TCDD/TCDF.  Correlations between
mass export rates  of 2378-TCDD/TCDF and a series of mill parameters
(including application rates of bleaching and extraction chemicals)
were generally quite low. Consequently, linear regressions of the
2378-TCDD/TCDF export  rates fit to  each bleaching parameter were
found to be poor predictors of individual  mill outputs.  However,

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                                                               19

significant positive  trends were observed  between average 2378-
TCDD/TCDF formation and the rate of  application  of  chlorine in the
C-Stage.

     Figure 4 is a  plot of 2378-TCDD formed,  as characterized by
export vector measurements, vs chlorine applied  in  the C-Stage for
kraft mills.   The data indicate a general trend of increasing 2378-
TCDD  with increasing  chlorine  application;  although,  as  noted
above, there appears to  be  only a weak correlation.   Plots of 2378-
TCDD vs chlorine ratio or kappa factor for all kraft mills yielded
similar results.  Increased substitution of chlorine dioxide for
chlorine  in   the  C-Stage  was weakly  correlated  with  decreased
formation of 2378-TCDD/TCDF mass.
                             Figure  4


               C12 vs. ADJUSTED TOTAL TCDD

                        KRAFT MILLS ONLY
         oo
         ?  100.00
         CO
         T3

         PU
         C/3
         Q
         Q
         (J
         H
10.00
              1.00
              0.10
         CO
         3
              0.01
                         50
                   100
150
200
                          C12 (Ibs/ton ADBSP)
     For certain  mills,  factors other  than chlorine application
appear to have had a more significant impact on formation of  2378-
TCDF  than   on  formation  of  2378-TCDD.     This  resulted   in

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                                                               20

uncharacteristically high ratios of 2378-TCDF to 2378-TCDD.   In a
number  of  cases  use  of  contaminated  oil-based  defoamers  was
reported  to  be responsible for  the  unusually high  formation  of
2378-TCDF.  Resampling at a few mills  after substitutions were made
confirmed this finding.

     5.   Kraft Mill Wastewater Treatment Findings

     Differences emerged between mills with Aerated Stabilization
Basin  (ASB)  and Activated  Sludge   (ACT)  wastewater  treatment
systems.   There was  significant evidence  that  mills using  ACT
treatment  exported  less effluent-based  2378-TCDD/TCDF and  more
sludge-based 2378-TCDD/TCDF on average than mills with ASB systems.
This is principally due  to  differences in management of biological
solids in each type of system; and, the method of sludge sampling
conducted for this study, which did not characterize sludge stored
in ASB systems.  Figures 5  and 6  illustrate the above findings for
2378-TCDD.  Results for 2378-TCDF were similar.
                             Figure  5



                 % OUTPUT BY TREATMENT

                         EFFLUENT TCDD
         Q
         Q
         U
         H
         c
         u
         3
         W
              100
               80
               60
40
               20
                           ACT
                      ASB
                              Treatment

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                                                               21
                            Figure 6

                  % OUTPUT BY TREATMENT

                           SLUDGE TCDD
          Q
          Q
          U
          9
          O
          O
          60
          •o
               100
               80
               60
40
               20
                           ACT
                      ASB
                              Treatment
     Further investigations were  made of  possible  relationships
between 2378-TCDD/TCDF mass exports in sludge  and effluent,  type
of wastewater  treatment  provided,  and levels  of  Total  Suspended
Solids  (TSS).   On average, TSS  concentrations in  ACT  treatment
system  effluents were  found  to  be  higher  than  those  in  ASB
treatment system effluents,  (60  mg/1  vs 48 mg/1).   Correlations
between effluent  concentrations  of TSS  and 2378-TCDD/TCDF  mass
outputs were fairly weak, suggesting that TSS levels were at best
only partially predictive of 2378-TCDD/TCDF partitioning to sludge
and effluent.

     When  data from  ACT  and ASB-type  mills  were combined,  a
significant  but weakly  correlated  positive  trend was  observed
between effluent 2378-TCDD/TCDF mass  and TSS  concentrations.   A
weakly  correlated  negative trend  was observed between TSS  and
sludge 2378-TCDD/TCDF.  For kraft mills using ACT treatment, higher
TSS levels were associated with higher sludge-based 2378-TCDD/TCDF
exports and lower effluent-based 2378-TCDD/TCDF exports

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                                                               22

     6.  Other 2378-Substituted CDDs and CDFs

     Bleached pulp, wastewater sludge and final wastewater effluent
samples from eight kraft mills and one sulfite mill were analyzed
for 2378-substituted  CDDs  and CDFs,  and total CDDs and  CDFs by
homologue class,  tetra through octa.  These analyses were conducted
to test the conclusion drawn in the Five Mill Study that 2378-TCDD
and 2378-TCDF were the principal  CDDs and CDFs found in pulp and
paper  mill exports,  when  considered in  terms  of EPA's  toxic
equivalence approach  (8).

     The  analyses were  completed by  Enseco-CAL.    Ten bleached
pulps, 9 wastewater sludges and 9 final wastewater effluents were
analyzed.   Duplicate  analyses were conducted  on  one sample from
each matrix.  Although there are  no reference analytical methods
for many of the 2378-substituted CDDs and CDFs, the data obtained
are considered  valid for  the purposes  intended based  upon the
identification and  quantitation  criteria used,  duplicate sample
results and limited matrix spike experiments.

     Tables 11,  12 and 13 present summaries of the results obtained
in  terms  of  the   median  concentration   and  the   range  of
concentrations   determined   for   each   matrix,   respectively.
Examination of the raw data and  the data summaries show that the
patterns of isomer profiles were  fairly consistent across matrices
within mills.  The most common 2378-substituted CDDs and CDFs  found
in  mill  exports, in  addition to 2378-TCDD and  2378-TCDF,  were
1234678-HpCDD, OCDD,  12378-  and 23478-PeCDF, and OCDF.  Non-2378-
substituted tetra-,  penta- and hexa-CDDs and CDFs were  often  found
at greater frequency  among the nine mills than the corresponding
2378-substituted  compounds.

     Tables   14   presents   the   2378-TCDD  toxic    equivalent
concentrations  (2378-TECs)  for  the  median values  presented in
Tables  11,  12   and   13,  and  for the sample  from each matrix
containing the highest concentrations of CDDs and CDFs. The  2378-
TECs were computed using the EPA and the I-TEF toxic  equivalency
approaches (8).   Table 15  presents comparisons of the  percentages
of the 2378-TECs attributable to 2378-TCDD and 2378-TCDF.   These
comparisons were made assuming  non-detected CDDs  and CDFs were
present at the detection level, and were  not present,  (i.e.,  zero
concentration).    The  results   indicate,  even  with the  most
conservative assumptions, that 2378-TCDD and 2378-TCDF  account for
the vast majority of the 2378-TEC in each sample.  This finding is
consistent with  results  from the  Five Mill  Study  (2).

     Bleached pulps manufactured  in British Columbia from sawdust
recycled   from certain  wood  treating operations  have exhibited
markedly different isomer profiles, with the HxCDDs more prevalent.
Those  findings  have  been  linked  to pentachlorophenol-based  wood
treating  operations   (9) .  This phenomena is not expected in the
United States since such materials are not suspected of being used
as  sources of fiber at U.S.  pulping or bleaching  operations.

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                                                               23
     Table 11:  Pulp and Paper Mill Bleached Pulps
2378-TCDD
Other TCDDs

12378 PeCDD
Other PeCDDs

123478 HxCDD
123678 HxCDD
123789 HxCDD
Other HxCDD

1234678 HpCDD
Other HpCDDs

OCDD
2378-TCDF
Other TCDFs

12378 PeCDF
23478 PeCDF
Other PeCDFs

123478 HXCDF
123678 HXCDF
234678 HXCDF
123789 HXCDF
Other HxCDFs

1234678 HpCDF
1234789 HpCDF
Other HpCDFs
Tetra- throuah Octa-CDDs and CDFs
(Results in
Median
6.4
ND (0.4)
ND (0.3)
ND (0.3)
ND (0.4)
ND (0.5)
ND (0.5)
ND (0.5)
3.3
2.8
46
18
37
ND (0.7)
ND (0.2)
4.5
ND (0.3)
ND (0.3)
ND (0.3)
ND (0.3)
ND (0.4)
ND (0.6)
ND (0.6)
ND (0.6)
ng/kg, or ppt)
No. of Detects
Rancre (10 samples)
0.4 to 124
ND (0.2) to 7.0
ND (0.1) to 1.4
ND (0.1) to 2.1
ND (0.2) to 0.4
ND (0.2) to 1.6
ND (0.2) to 0.5
ND (0.2) to 8.8
2.3 to 8.4
1.9 to 8.4
28 to 81
1.4 to 716
2.7 to 810
ND (0.1) to 3.9
ND (0.1) to 4.7
ND (0.2) to 17
ND (0.2) to ND (0.6)
ND (0.1) to ND (0.4)
ND (0.2) to ND (0.4)
ND (0.1) to ND (0.4)
ND (0.2) to 1.7
ND (0.1) to 0.8
ND (0.1) to ND (2.1)
ND (0.1) to 2.3
10
2
2
3
1
2
1
3
10
10
10
10
10
4
3
9
0
0
0
0
4
3
0
3
OCDF
2.2
ND (2.8) to 4.3
8

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                                                               24
     Table 12:  Pulp and Paper Mill Wastewater Sludges
2378-TCDD
Other TCDDs

12378 PeCDD
Other PeCDDs

123478 HXCDD
123678 HxCDD
123789 HXCDD
Other HxCDD

1234678 HpCDD
Other HpCDDs

OCDD
2378-TCDF
Other TCDFs

12378 PeCDF
23478 PeCDF
Other PeCDFs

123478 HxCDF
123678 HXCDF
234678 HXCDF
123789 HXCDF
Other HxCDFs

1234678 HpCDF
1234789 HpCDF
Other HpCDFs
Tetra- throuah Octa-CDDs and CDFs
(Results in
Median
63
ND (1.5)
ND (2.5)
ND (2.9)
ND (3.1)
ND (3.2)
ND (3.9)
11
37
35
698
233
547
6.2
4.7
14
ND (2.5)
ND (1.4)
ND (1.7)
ND (1.7)
5.2
6.6
ND (1.6)
12.7
ng/kg, or ppt)
No. of Detects
Ranae (9 samples)
ND (6.3) to 180
ND (1.1) to 837
ND (1.4) to 28
ND (1.6) to 1,280
ND (1.5) to 40
ND (1.7) to 95
ND (1.7) to 80
ND (3.1) to 2,180
18 to 490
18 to 447
263 to 1,780
13 to 1,150
37 to 2,310
ND (1.2) to 22
ND (0.9) to 38
ND (2.0) to 268
ND (0.9) to 31
ND (0.9) to 33
ND (0.9) to 34
ND (0.9) to ND (4.0)
ND (0.9) to 219
ND (3.6) to 70
ND (1.2) to 10
ND (1.2) to 63
8
2
1
2
1
1
1
8
9
9
9
9
9
6
6
5
2
1
1
0
7
7
1
8
OCDF
22
ND (54) to 168

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                                                               25
     Table 13:  Pulp and Paper Mill Wastewater Effluents
                Tetra- throuh Octa-CDDs and CDFs
(Results in pg/kg,  or ppq)

  Median         Range
                                                   No. of Detects
                                                     (9 samples)
2378-TCDD
Other TCDDs

12378 PeCDD
Other PeCDDs

123478 HxCDD
123678 HXCDD
123789 HxCDD
Other HxCDDs

1234678 HpCDD
Other HpCDDs

OCDD
     42      ND (11)  to 98
     34      ND (3)  to 138

  ND (9.6)    ND (2.8) to ND(25)
     9.6     ND (9.6) to 130

  ND (12)     ND (6.6) to ND (12)
  ND (12)     ND (6.6) to ND (24)
  ND (12)     ND (6.6) to ND (23)
  ND (17)     ND (6.6) to ND 360

    170      77 to 270
    120      ND (27)  to 160

  3,000      1,000 to 4,600
                         8
                         7

                         0
                         5

                         0
                         0
                         0
                         4

                         9
                         8
2378-TCDF
Other TCDFs

12378 PeCDF
23478 PeCDF
Other PeCDFs

 .23478 HxCDF
 L23678 HxCDF
 !34678 HxCDF
 L23789 HxCDF
 )ther HxCDFs

 .234678 HpCDF
1234789 HpCDF
Other HpCDFs
    120      12 to 840
    270      43 to 1,460

  ND (7.2)   ND (2.2) to 36
  ND (6.3)   ND (2.2) to 33
     21      ND (2.2) to 71

  ND (8.4)   ND (4.8) to ND  (15)
  ND (7.1)   ND (4.8) to ND  (15)
  ND (8.2)   ND (4.8) to ND  (15)
  ND (6.2)   ND (2.5) to ND  (15)
  ND (15)    ND (5.2) to 54

  ND (23)    ND (13) to 44
  ND (22)    ND (6.4) to ND  (41)
     36      ND (13) to 79
                         9
                         9

                         2
                         2
                         5

                         0
                         0
                         0
                         0
                         4

                         3
                         0
                         7
OCDF
    190
ND (180) to 230

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                                                               26
     Table 14:  2378-TCDD Toxic Equivalents
                Nine Mill Sampling Program
                                 (Results in ng/kg,  or ppt)
                           EPA-TEF/87
                                          I-TEFs/89
BLEACHED PULP
 Median
 Worst case

WASTEWATER SLUDGE
 Median
 Worst case

WASTEWATER EFFLUENT
 Median
 Worst case
                          ND=0
                8.24
              197.4
               88.0
              216.3
                0.055
                0.142
                        ND=DL
  8.56
198.2
 89.8
220.6
 0.063
 0.156
               ND=0
  8.28
198.4
 90.1
218.5
 0.059
 0.147
           ND=DL
  8.83
199.4
 93.1
223.8
 0.073
 0.177
   Note:  (1)  "Worst case" represents the sample with the
               highest levels of 2378-substituted CDDs and CDFs.
     Table 15:  2378-TCDD Toxic Equivalents
                Nine Mill Sampling Program
                Percent of 2378-TEC Attributable to 2378-TCDD/TCDF
BLEACHED PULP
 Median
 Worst case

WASTEWATER SLUDGE
 Median
 Worst case

WASTEWATER EFFLUENT
 Median
 Worst case

   Note:
                                (Results in percent, %)
                           EPA-TEF/87
                          ND=0
                         ND=DL
              ND=0
                                           I-TEFs/89
           ND=DL
99.5
99.1
98.1
98.4
98.4
98.6
95.8
98.7
96.1
96.4
86.0
89.7
99.0
98.6
95.8
97.4
91.7
95.1
92.8
98.1
92.7
95.1
72.7
79.0
(1)   "Worst case"  represents the sample with the
     highest levels of 2378-substituted CDDs and CDFs.

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                                                               27
                           REFERENCES
1.   Amendola,  G.,  et. al., The Occurrence and  Fate  of PCDDs and
     PCDFs  in   Five   Bleached  Kraft  Pulp  and  Paper  Mills.
     Chemosphere, Vol. 18,  Nos. 1-6,  pp 1181-1188,  1989.

2.   U.S. EPA Cooperative Dioxin Screening Study. U.S. EPA, Office
     of Water Regulations and  Standards, Washington,  D.C.,  March
     1988, EPA-440/1-88-025.

3.   U.S. EPA/Paper Industry Cooperative Dioxin Study, Washington,
     D.C., April 26, 1988.   (104 Mill Study Agreement)

4.   USEPA/Paper Industry Cooperative Dioxin Study. "The 104 Mill
     Study". Statistical  Findings and Analyses. USEPA, Analysis and
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5.   USEPA/Paper Industry Cooperative  Dioxin Study;  The 104 Mill
     Study. Technical  Bulletin No.  590.  National  Council  of the
     Paper Industry for Air and Stream Improvement,  Inc., New York,
     New York,  May 1990.

6.   Whittemore, R.C., et. al., U.S.  EPA/Paper Industry Cooperative
     Dioxin Study;  The  104 Mill  Study,  presented  at Dioxin '89,
     Toronto, Ontario, September,  1989.   (accepted  for publication
     in Chemosphere)

7.   Summary of Technologies  for the Control  and  Reduction  of
     Chlorinated  Organics  from  the  Bleached  Chemical  Pulping
     Subcateaories of the Pulp  and Paper Industry. U.S.  EPA, Office
     of  Water   Regulations  and  Standards  and  Office  of  Water
     Enforcement and Permits, Washington, D.C., April  1990.

8.   Interim  Procedures  for  Estimating Risks Associated  with
     Exposures to Mixtures  of  Chlorinated Dibenzo-p-Dioxins and  -
     Dibenzofurans  (CDDs and CDFs) and 1989 Update. U.S. EPA, Risk
     Assessment  Forum,  Washington,  D.C., March 1989,  EPA/625/3-
     89/016.

9.   Voss,  R.H.,  et.  al.,  Some New  Insights  in  the  Origins of
     Dioxins Formed Purina Chemical Pulp  Bleaching. Pulp and Paper
     Canada, 89  (12).

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