United States
         Environmental Protection
             Ottice ot Hesearcn ana
             Washington, DC 20460
         EPA 600 9-90 021
             September 1990
Workshop on
Methods for
Investigation of
Waterborne Disease
         Summary of

                                  EPA 600'9-90 021
                                  September 1990
      Workshop on  Methods for
Investigation of Waterborne Disease

    Summary of Recommendations
              OctfrBer 11-13,1988
                fHotel, Tabor Center
                mver, Colorado
        I Gunther F. Craun, Project Officer
       f.S. Environmental Protection Agency


       Janet L. McGoldrick, Project Manager
 Association of State Drinking Water Administrators
       Health Effects Research Laboratory
       Office of Research and Development
       U.S. Environmental Protection Agency
        Research Triangle Park, NC 27711


    This document has been reviewed in accordance with U.S Environmental
Protection  Agency policy and approved for publication   Mention of  trade
names or commercial  products  does not  constitute  endorsement or
recommendation for use.


                         Planning Committee

Gunther Craun
Chief, Population Studies Section
Health Effects Research Laboratory
US Environmental Protection Agency

Wade Miller, Executive Director
Association of State Drinking
Water Administrators

Janet McGoldrick
Deputy Executive Director
Association of State Drinking
Water Administrators (ASDWA)

Stuart Castle
Program Manager. Drinking Water Section
New Mexico Health and Environment Department

Richard Vogt
Vermont Department of Health and
Member, Council of State and
Territorial Epidemiologists

Nathan Schaffer
Medical Epidemiologist
Bacterial Diseases Division
US Centers tor Disease Control

Peter Karalekas, Chief
Public Water Supply Section, Region I
US Environmental Protection Agency

                       Table of Contents

Planning Committee
Recommendations 	                     2
 Appendix A: Workshop Program  	   12
 Appendix B: Abstracts of Presentations   	   19
 Appendix C: Listing of Participants	   44


    The  Environmental  Protection  Agency's (EPA)  Health Effects  Research
Laboratory  and  the  Association  of  State  Drinking  Water  Administrators
(ASDWA) planned and conducted  a workshop for state epidemiologists and
drinking  water officials  in October 1988.  for the purpose of improving  the
investigation and reporting of waterborne disease outbreaks.  Additional and
more accurate information is needed on the  causes  of waterborne outbreaks.
Such data  will  enable  researchers to  evaluate  the  adequacy of current
regulations, surveillance activities, water treatment practices, and  source water
protection policies.
    The  workshop  brought  together  research  scientists, epidemiologists.
engineers, and microbiologists from government and academe to discuss and
exchange  information  on outbreak  investigations  including  analytical
procedures, water supply engineering, surveillance, and other related regula-
tory activities. A goal of the workshop was to improve  communication among
outbreak investigation personnel.
    Plenary sessions provided participants with  basic concepts in
epidemiology, water  supply engineering, clinical and water sample  collection
and analyses.   Examples  of  several  recent outbreak investigations  were
included to reinforce these concepts and to  provide an understanding of the
investigative process.  More detailed  discussions  were held during breakout
sessions. Articles based on the presentations will be published as a separate
volume by the EPA.
    The  latter  portion  of the  workshop  was  designed  to allow for the
identification of research, training, and other  requirements needed to prevent
waterborne outbreaks as well as improve their recognition, investigation, and
reporting. Through the breakout sessions and through  audience  participation.
a  number  of  recommendations were  made.   The recommendations are
summarized on the following pages. A copy of the workshop program is also
included in Appendix A. Abstracts of presentations are  contained in  Appendix
B  and a listing of participants is included in Appendix  C.
    This document has been reviewed in accordance with U.S. Environmental
Protection Agency policy and approved for  publication.  Mention of trade
names or commercial products does not constitute endorsement or
recommendation for use.


    Breakout  session  chairpersons and speakers  met  following their
respective sessions to discuss various issues brought forth ana to  deveioo
recommendations based upon audience discussion  and participation   The
recommendations were  then presented to all workshop participants through a
series of panel discussions.   The audience was provided an  opportunity  10
expand  upon  these issues  and recommendations.  A summary  of  the
recommendations by subject area is included below.

I.   General Recommendations
    1) Workshop participants identified a need for increased funding for:
      a)   laboratory support, particularly  for those agents which are difficult
           to identify;
      b)   field  investigation  personnel in order to  adequately  respond  to
           outbreaks; (It was noted that multi-disciplinary teams are required
           to provide the expertise needed to handle the types of outbreaks
           that are typically  occurring.  It  was recommended  that additional
           resources be available to EPA and Centers for  Disease Control
           (CDC) officials to  provide technical assistance  to  the states for
           outbreak investigations.]; and
      c)   computer resources at the state and local  levels to assist with data
    2) The states requested  that more laboratory support be made available
      when requested of CDC  and EPA to assist  m the identification  of
      etiologic agents, especially those requiring specialized  analysis.  The
      states also  requested that  EPA provide engineering  evaluations  of
      outbreak situations as  they did m the 1970s

II.  How to Improve Outbreak Reporting, Disease  Surveillance, and
    Related Research Issues

    Improved outbreak reporting and disease surveillance requires better
communication, coordination, and cooperation at local, state, and federal levels
between epidemiologists, drinking water authorities, and laboratory officials
The voluntary reporting  of waterborne outbreaks should be continued with
increased efforts on improving collaboration among various agencies that
share responsibilities for investigation and reporting.
    1) Designate a waterborne disease surveillance coordinator at CDC. EPA,
       and  in each  state to  act  as  the key  link m  communication between
       agencies.    These coordinators  should be   MPH-tramed. mid-level
      epidemiologists or public health engineers and should be encouraged
       to provide timely feedback m:
       a)    gathering and summarizing surveillance data.
       b\   maintaining surveillance by reguSai contact with state health

   c)   obtaining computer reports of epiderruoiogicai investigations: and
   d)   summarizing  the pertinent  data  (or  publication  m  annual
       surveillance  summaries, and   scientific  literature  {Routine
       distribution of these reports should be made to the states.)
2) Publish  a directory  of names,  addresses and telephone numbers
   including the surveillance  coordinators,  state  drinking  water
   administrators, and state public health laboratory directors and  send to
   all individuals listed.  The  directory should be updated periodically
3) Hold periodic  conferences such  as  this workshop to bring  together
   epidemiologists and drinking water personnel for the purpose of:
   a)   reviewing general trends and recent outbreaks of waterborne
   b}   discussing the need for changes in control efforts;
   c)   considering future research priorities;
   d)   improving communication between the two groups:
   e)   generating new ideas; and
   f)   introducing new personnel to the complexities of waterborne
4) Create a working group to redesign  the current waterborne outbreak
   reporting form to require the following:
   a)   additional detail on the nature of the affected water supply system
       and on the specific type of treatment being used:
   b)   specific information on water quality including coliform and
       turbidity data and treatment before as well as during an outbreak;
   c)   additional detail on contributing factors relating to problems m
       filtration as well as disinfection; and
   d)   more easily codable answers.
5) Promote the electronic transmission of surveillance data as a long-term
   goal.  Such an approach will establish an interactive on-line data base
   from which public  health officials can  both  enter and  extract data
6) Encourage  laboratory  based  surveillance of  potential  waterborne
   diseases where feasible, including Giardia and Cryptosporidium.
7) Assuming the ultimate goal  of  reducing  the number of waterborne
   disease outbreaks is successful, other  outcome  measurements {i.e.,
   rare  outbreaks will become  more difficult to  use as  gauges)  are
   necessary  to monitor the successful  control  program. Potential
   measures include:
   a)   population covered;
   b)   percent of surface water systems using filtration;
   c)   percent of groundwater systems using disinfection.'filtration;
   d)   percent of systems participating in continuing education programs;
   e)   measures of operator knowledge and competence.
8) As  with  any  surveillance system, the  data collected  represent  a
   balance between the essentials  required and the desire to keep the
   investigation process as shorl as possible  However,  specific  special

       studies can be conducted-collecting more information about reported
       outbreaks over a shorter period of time. These specific studies can be
       viewed as a "base" for later, more detailed investigations   Examples of
       some potential investigations include.
       a)   relating outbreak  data  to  the  denominator  of  all  water supply
           systems:  and
       b)   comparing  the  characteristics  of operators  of  supply  systems
           involved in outbreaks with those of al! opera tors

It).  How to Improve Epidemiological Investigations and Related
    Research Issues in Epidemiology Methods

    Perhaps  the most important issue discussed was the  fact that only 50
percent of the  waterborne  outbreaks  are  investigated thoroughly enough  to
establish an etiotogic agent. It was recommended that additional research be
conducted to identify the etiologic agents involved in waterborne outbreaks
that are now  classified as "unknowns."  This would  require  increased labora-
tory  support  and quicker recognition of  potential  outbreaks so  that  timely
samples could be collected.  Until the etiologic agents are identified, one
cannot assess  the appropriateness of technologies to  mitigate occurrence.
Such an awareness  was identified  as critical given  EPA's current position  of
promulgating regulations under  the  1986  Safe Drinking Water Act (SDWA)
    1) Field personnel must be  more thoroughly trained. Attention needs  to
       be given to the type of training that  should be provided and the means
       through which it can be  given  [It  was noted that formal  training for
       epidemiologists previously provided  from the CDC  has been useful
       Concern was  expressed  that adequate resources may not be applied
       for such training in the  future.  It was requested that the  record reflect
       the recommendation that CDC  continue training  efforts  m this area ]
       The need  for brief but  substantive  training for water supply engineers
       in  the area of epidemiology and for laboratory personnel  in the area  of
       outbreaks  was also identified.
    2) An information network that identifies the critical  issues  to be investi-
       gated during  specific outbreaks should be  established for  research
       personnel. [A  network  to allow state  and  federal  officials  to
       communicate aspects of  particular  investigations that may be useful  to
       others was noted as a need.  Some mechanism  for following through
       on  whether  approaches to mitigating public  health   risks  due  to
       outbreaks  (i.e.. boil water notices) are successful was also identified as
       a need.)
     3) Questionnaires used during outbreak investigations should be included
       with final  reports.  Such a  practice will  aid m the  evaluation  and
       interpretation of epidemiologic  data   Further recommendations
       concerning the survey instrument included:
       a)  a list of the minimum data set(s) required to  be gathered for each
           type of outbreak investigation  should be compiled, the lists would

          serve as useful aids  during the hectic moments of outbreak in-
          vestigations; and
      b)  investigators  should be  cognizant  that methods  for  evaluating
          outbreaks are crude at best: investigators should not be placed m
          a position to apologize for the lack of tools or to make current tools
          seem more sophisticated.
      [It was   noted during discussion  that CDC has  a  software package
      available to aid in the development of survey instruments  and m the
      ensuing analyses.  Although  the user   must  write  his her own
      questionnaires, some  thought  has been  given  to  providing  sample
      surveys with future upgrades of the software.  The  software  is
      compatible with  IBM  and  is available for approximately S18 from the
    4) The results of outbreak investigations should be made available to the
      appropriate water supply operators in  a timely manner to avoid future
      occurrences. Investigation reports  should also be utilized  as education
      tools  with water supply operators.  One suggestion was  to occasion-
      ally survey  operators regarding  their  knowledge  of  outbreak
    5) The media should be utilized as a vehicle for:
      a)  improving case ascertainment  during the investigation period (i.e.,
          by  publicizing outbreaks, the public may be more encouraged to
          seek medical  attention and, therefore, be  counted);  [Some
          workshop participants expressed  concern in this  area  and noted
          that publicity may introduce biases into  the  data  collection
          process; others,  however,  noted  that  the media should  not  be
          relied  upon  only in emergency situations.    In  other words,  a
          relationship should  be built and supported between research reg-
          ulatory personnel and  the media on a daily basis.],  and
      b)  in advising the public of actions they may  (should) take during
          specific outbreaks (i.e.. boil  water notices, etc.).

IV.  How  to Improve the Collection and Analysis of Clinical and
    Environmental Samples

    There is a large category of etiological agents  associated  with waterborne
outbreaks  which are unidentified partly  because of 11nadequate  sample
collection; 2) inadequate analysis;  and 3) non-recognition  of agents  as  the
cause of disease.
    There is also  a lack  of resources for both  clinical and environmental
sample  analysis.  Specific needs are a) protocols for specimen and sample
collection; b)  personnel  for collection of environmental  samples;  c)field
equipment for appropriate sampling; and d) laboratories which  can recover
and identify  the variety  of bacteria,  protozoa and  viruses which may  be  the
cause of a specific outbreak.

1) Epidemiologists  must  keep  abreast  of  newly  identified  entenc
   organisms which have the potential  for causing waterborne  disease
   such as:
   a)   caliciviruses;
   b)   Small Round Viruses (SRV);
   c)   Mycobactena:
   d)   Isospora; and
   e)   enteric non-A, non-B hepatitis virus(es).
2) Improvements in the collection of clinical samples which will facilitate
   agent identification include:
   a)   early collection immediately at the onset of illness (within the first
       24-48 hours);
   b)   large volume of fecal samples;
   c)   storage of fecal samples at 4 degrees Centigrade;
   d)   fecal samples sent to laboratories as soon as possible after
   e)   fecal samples separated and stored for various type analyses (for
       various types of agents); and
   f)   collection of blood samples if possible (serological specimens
       would not be required to be collected as quickly as stool samples;
       research is needed to detect agents through serological analysis).
3) Recommendations for environmental sampling include:
   a)   collect samples as soon as outbreak is identified;
   b)   collect minimum of three replicates from individual source (well) or
       eight to  10 samples from distribution system, including
   c)   sample for broad range of  microorganisms;
   d)   collect a minimum of one liter for bacteria and 400 liters for viruses
       and parasites; and
   e)   include, if possible, an environmental microbiologist with proper
       experience for field sampling on the investigation team.
4) There should  be improved communication  and coordination  between
   laboratories, state health agencies and the CDC  regarding:
   a)   whether information on appropriate procedures is available:
   b)   the prioritization  and urgency of sampling; and
   c)   the use  of laboratories as active participants in investigations as
       opposed to service entities.
5) A list of contacts for laboratory support should be compiled.   The list
   should include guidance for appropriate laboratory quality assurance
   and quality control procedures. An individual or organization  needs to
   be  identified  to update  the  list  periodically and to distribute  to
   appropriate  officials  (i.e., state and federal  epidemiologists, microbio-
   logists and engineers).
6) States need  to identify additional  sources  of laboratory support and
   communicate with such entities to ensure that the most up-to-date and
   progressive  techniques are being  used.  Such sources of additional
   laboratory support may include:
   a)   universities.

   b)   private companies;
   c)   large utilities;
   d)   other state facilities; and
   e)   federal laboratories.
7) There is a  need  for  a central  agency or  group  to  disseminate
   information regarding 1ield sampling and sample analysis.  Little  or no
   contact  exists between laboratory  microbiologists  and  the  officials
   being served (i.e., state and federal regulators).  One suggestion is that
   the  states  should  work m conjunction  with  EPA regional offices  to
   develop information and communication networks.
8) The coliform standard as written is inadequate to assess the microbial
   quality of water.  The standard  has  limitations for  some bacteria!
   pathogens; also,  the  absence  of coliforms  does  not indicate the
   absence of viruses or parasites.  It was  recommended that research
   studies  be planned  and conducted to identify better  or  additional
   indicator organisms.
9) Specific  monitoring  strategies  can  be  developed  prior  to the
   occurrence of an outbreak.  The strategies should:
   a)   be incorporated into the sanitary survey;
   b)   include the testing of pilot plants; and
   c)   evaluate existing systems at risk (e.g., no filtration or poor
   One suggestion was made to require increased monitoring during cold
   seasons since epidemics often occur during these periods.
10) Surrogates for treatment plant efficiency include:
   a)   particulate analysis;
   b)   Hartmanellid amoeba; and
   c)   bacteriophage. such as MS2 and F2.
   These can  be  used to judge  the efficiency of water  treatment
   processes and will  supplement the routine monitoring of cofiforms.
11) The development and use of  innovative  technology  and exploratory
    methodologies for analysis should be encouraged.
    One suggestion was made for  research  to evaluate the optimal type
    of filtration media to  use  to concentrate water samples.  Additional
    research is  also  needed on  the  identification of various strains of
    protozoa that are capable of infecting humans as well.
    There  is a shortage of reagents for virus testing and identification.
    Current detection techniques  rely  upon  the electron  microscope
    which requires  one million particles per cubic centimeter (cc). When
    humans  shed such quantities, it is typically in the first two  days of
    illness.   Unfortunately, samples are not often obtained  during this
    period.   Moreover, samples taken at  home  are often stored  at cold
    temperatures which may distort  the morphological characteristics of
    the virus(es). A suggestion was  made by some state officials that the
    CDC inform state epidemiologists of the exact nature  of samples they
    wish to receive.  The comment was  made that states may  not  be
    aware  the CDC  dessres  samples in such  large  volume.    Also.

        conflicting information has  been received from  the  CDC regarding
        storage temperatures. The  Agency was asked to clarify these issues
        and provide some form of protocol to the states.
     12)   Method efficiencies need to be assessed:  funds  are  needed lor
           methods development and the standardization of methods
     13)   Readiness for environmental sampling is necessary and needed
     14)   Research should  be  funded during outbreak occurrences   The
           knowledge gained during these real life situations will contribute
           greatly to the investigation process.  It was suggested that such
           research practices, in the long run, are cost-effective.

IV.  Prevention of Outbreaks Through Engineering Controls and Water
    Quality Surveillance

    Comments made under  this subject  heading are preventive in nature.
Breakout group participants noted that the preventive approach to engineering
and water quality issues will do more to mitigate waterborne disease outbreaks
than will  a reactionary  approach.   Analysis  of  the  cause  of  waterborne
outbreaks can provide information on adequacy of treatment technologies and
surveillance activities. Regulatory and preventive  measures should be based
on  these data.current  surveillance efforts  should  also  be evaluated  to
determine  if the  routine  testing for coliforms is  effective  in  preventing
waterborne outbreaks and if  additional indicators of water  contaminants  are
needed.  The comments and recommendations made  are organized accord-
ing to the topical subjects presented during the session. These comments are
followed  by more  general  recommendations that   resulted from  group
    1) Sanitary surveys of public water systems should:
       a)  include a review of all aspects of operation and maintenance of
           distribution systems,
       b)  include physical inspection of all above ground facilities and review
           of operating  records; and
       c)  evaluate cross-connection control programs.
    2) Watershed protection programs should:
       a)  characterize the watershed(s) and contaminant sources:
       b)  identify goals and measures to control contamination;
       c)  consist of monitoring  and evaluation components to provide
           feedback on the effectiveness of controls;
       d)  be developed on a site-specific basis;
       e)  incorporate a multiple-barriers approach to achieing the best water
           quality (not necessarily incorporate beaver control as part of the
           management strategy): and
       f)   address all surface supplies (not just unfiltered systems) to obtain
           the best water quality possible

3) Treatment plant evaluations should focus on:
   a)   facilities and their condition;
   b)   operating procedures:
   c)   water quality;
   d)   collecting samples in instances when complaints of illness have
       been made (although not very  practical); and
   e)   disinfection needs to be carefully designed to maximize its efficacy
       as a unit process.
4} With respect to the determination of chlorine contact time (Ct)  values,
   comments such as the below were made;
   a)   Ct values are based upon limited data sets;
   b)   Ct values  are  included  in EPA's  Surface  Water Treatment  Rule
   c)   the majority of G/ard/a/chlorine data for Ct values are  based on
       Hibler's data which leads to conservative values;
   d)   there is a need to investigate mechanisms to combine data sets to
       find less conservative Ct values;
   e)   a need exists  for continued research in the area of Ct  values,
       Giardia strain varieties and the organisms' resistance to chlorine;
   f)   additional  Ct data is needed  for eg (disinfection research  should
       continue even after the T986 SDWA  regulations  have been
       implemented; and
   h)   Ct values provide a good  framework or method  for looking  at
       inactivation but do not provide the best framework for  reviewing
       overall plant operation.
5) State regulatory agencies need  to have specific  requirements  for the
   sanitary protection of water distribution systems, including:
   a)    proper construction and maintenance of distribution storage
       reservoirs; and
   b)   disinfection of new and repaired water mains.
6} States should  have specific requirements that place responsibility on
   water systems to conduct  comprehensive cross-connection  control
   programs.  Such programs should include:
   a)   a cross-connection survey and plan review by qualified specialists;
   b)   the testing of devices by certified backflow prevention device
7) Water quality  in  distribution systems  caused by persistent coliform
   occurrence problems pose a problem  for some utilities in complying
   with federal and state drinking water standards. In  such instances,
   factors to be examined should include:
   a)   effects  of varying assimilable organic carbon  (AOC)  levels  in
       treated water on the organisms;
   b)   specific levels of AOC  that are required to stimulate growth  of
       different coliform organisms;

   c)   need for  specific  methods  to inhibit coliform growth  in systems
       with colonization problems;
   d)   establishing the health significance of colonized conforms; if there
       is no health threat, how  does the utility resolve  the  compliance
       issue; and
   e)   variations in water quality and corresponding  health effects (wide
       variations within distribution systems exist, particularly  when water
       comes from a variety of sources); such variations  pose difficulties
       in tracing waterborne disease outbreaks.
8) In the area of  treated water quality versus  coliform  noncompliance
   problems, the following comments were made:
   a)   there is no such thing as a "representative" sample;
   b)   the use of permanent sampling taps is probably okay; and
   c)   sampling  all on one day per month is not recommended.
   d)   research  is needed to develop  new or  additional  indicators for
       assessing water quality and health risks.
9) The design of  distribution systems were  discussed.   The following
   comments were made concerning this issue:
   a)   systems are designed for water distribution as opposed to water
       quality; and
   b)   hydraulic design should be considered since it can influence water
       quality (at least in  large systems).
10)    General recommendations include the following:
   a)   greater coordination is needed on both the state and federal levels
       between various programs that affect watershed and source water
       quality  (especially between Clean  Water  Act and Safe Drinking
       Water Act) personnel/agencies);
   b)   greater coordination  is  also needed between  drinking water
       regulators and sewage dischargers;
   c)   better communication and  coordination regarding epidemiology,
       regulation and monitoring o( public water systems is encouraged
       at the state  level;
   d)   a balance  of resources must be  sought  between research,
       technical assistance, and monitoring in  drinking water regulatory
   e)   regulations  should be compatible to the maximum extent possible
       and view water systems as one entity;
   f)   regionalization of systems for  physical connections  or  as a
       management option for small systems should be promoted;
   g)   knowledge-transfer  among  the  states  should   be  promoted
       especially with regard to handling non-community systems;
   h)   opportunities for  the  private  sector  in  water  supply  should  be
       examined (i.e.,  sanitary  surveys, laboratory certification, operator

    training, vulnerability assessments,  etc.): potential  problems
    associated with  this approach should be  evaluated  (i.e..  loss of
    institutional memory, lack ol continuity, etc.);
i)   training of state and  local drinking  water regulatory  personnel
    should be conducted (continue to be conducted) by EPA regarding
    SDWA implementation;
j)   finished water sources should be  protected  from contamination
    (i.e., use of reservoir covers, etc.):
k)  a mechanism for timely reporting of waterborne disease outbreaks
    should be constructed and  disseminated  to regulatory  and utility
I)   a major goal of drinking  water regulatory efforts should  be the
    prevention of waterborne disease by concentrating on deficiencies
    which have caused outbreaks and evaluating the effectiveness of
    current  water quality  surveillance  efforts (i.e.  routine  coliform
    sampling) in preventing outbreaks: and
m)  there is a need  for basic research to be conducted at the  federal
    level  and for the delivery  of research  findings in the form  of
    technical assistance to the states; while some states have continu-
    ing  experience  with  waterborne   disease  outbreaks  and
    investigations, other states are not in such a position and  require
    the knowledge  base  developed by other  states  and the  federal


   Workshop on Methods for Investigation of Waterbornc
                     Disease Outbreaks

                       October 11-13. 1988
                   The Westm Hotel. Tabor Center
                        Denver, Colorado

                     Final Schedule of Events


10:00 a.m.   REGISTRATION (Foyer) to 12:30 p.m.

                       OPENING SESSION
                        Tabor Auditorium

Session Moderator. Stuart P. Castle, ASDWA and  New Mexico Environmental
Improvement Division

12:30p.m   WELCOME
           Stuart P. Castle

           Gunther F. Craun, EPA

           Gunther F. Craun

           Paul S. Berger and Stig E. Regli, EPA


1:45 p.m    Federal Responsibilities and Requirements
           Robert V. Tauxe, CDC

2:00 p.m.    State and Local Responsibilities
           Lawrence R. Foster, Oregon Health Division

           Richard L. Vogt. Council of State and Territorial Epidemiologists
           and Vermont Departmenl of Health


3:00 p.m.    Principles of Water Filtration Gary S. Logsdon. EPA

3:30 p.m.    Principles of Drinking Water Disinfection
           John C. Hoff, EPA

           Edwin C. Lippy, US Public Health Service-Retired

           Joan B. Rose, University of Arizona

5:00 p.m.    DISCUSSION


                   SESSION TWO: CASE STUDIES
                         Tabor Auditorium

Session Moderator: Peter C. Karalekas Jr.. EPA


8:30 a.m.    Epidemiologic Characteristics of Waterborne Cryptosporidiosis
           Dennis D. Juranek, CDC

9:00 a.m.    Troubleshooting an Existing Treatment Plant
           Gary S. Logdson, EPA

9:30 a.m.    Discussion

           JuSie Parsonnet, CDC


10:30 a.m.   Epidemiologic Perspective
           George P. Kent. Stanford University School of Medicine
           (formerly with CDC)

11:00 a.m.   Engineering Perspective
           John J. Higgins, Massachusetts Department of Environmental
           Quality Engineering

11:30 a.m.   Discussion

           Jay R. Poliner, Eastern New York Occupational Health Program
           (formerly with CDC)

           Charles W. LeBaron. CDC

12:20 p.m.   Discussion

           Lawrence Room A

Chairwoma.  Patricia A. Murphy, EPA
Rapporteur: Gayle J. Smith. Utah Department of Health

           A. Murphy

           Charlotte A. Cottrill. EPA

           Neal D. Traven, University of Pittsburgh

           Neal D Traven

           Gayle J. Smith

4.30 p.m.    DISCUSSION

           Lawrence Room B

Chairman: Gary S. Logsdon, EPA
Rapporteur: Stuart P. Castle, ASDWA and New Mexico Environmental
Improvement Division

           Joseph L. Glicker, Portland Water Bureau

           Peter C. Karalekas Jr., EPA

           Gary S. Logdson

           Robert M. Clark. EPA
           Robert M. Clark

4.30 p.m.    DISCUSSION

           Curtis Room

Chairwoman: Joan B. Rose, University of Arizona
Rapporteur: Frank W. Schaefer III, EPA


2:00 p.m.    Bacterial
           Julie Parsonnet, CDC

2:30 p.m.    Protozoan
           Dennis D. Juranek. CDC

3:00 p.m.    Viral
           Charles W. LeBaron. CDC

3:30 p.m.   Analysis of Water Samples for Bacterial Pathogens
           Gerard N. Stelma Jr., EPA

4:00 p.m.   Virological Analysis of Environmental Water Samples
           Christon J. Hurst, EPA

4:30 p.m.   Analysis of Water Samples for Protozoa
           Jan L. Sykora. University of Pittsburgh

5:00 p.m.   DISCUSSION

Tabor Auditorium

Session Moderator: Janet L. McGoldnck, ASDWA

Chairwoman: Patricia A. Murphy

Panel Members:
           Charlotte A. Cottrill
           Laurence R. Foster
           Julie Parsonnet


Chairwoman: Joan B. Rose

Panel Members:
           Charles W. LeBaron
           Chnston J. Hurst
           Frank W. Schaerfer III
           Gerard N. Stelma Jr.
           Jan L. Sykora
           Jay Vasconcelos


Chairman: Gary S. Logsdon

Panel Members:
           Stuart P. Castle
           Robert M. Clark
           Joseph L. Glicker
           John C. Hoff
           Peter C. Karalekas Jr.
           Donald J. Reasoner
           Stig E. Regli


Chairman: Robert V. Tauxe

Panel Members:
           Paul S. Berger
           Guniher F. Craun
           Dennis D. Juranek
           Richard J. Karlin
           Richard L. Vogt

           Stuart P. Castle, ASDWA and Gunther F. Craun, EPA

12:15 pm   ADJOURNMENT

        APPENDIX B

Workshop Objectives.  GUNTHER F. CRAUN  (Health  Effects  Research
      Laboratory, US Environmental Protection Agency. Cincinnati. OH).

    Only a fraction of the waterborne outbreaks that occur m the United States
are recognized, investigated, and reported, and for those outbreaks  that are
reported, an etiologic  agent is identified in only half  of them.  The  primary
purpose of this workshop is to improve the investigation and reporting  of these
outbreaks so that better  information will be available  on their causes.  This
information is  necessary to determine the adequacy  of current surveillance
and  regulations  to  prevent the  waterborne  transmission of disease.   The
identification  of  etiologic agents  is  important  to evaluate  current  water
treatment technologies and source water protection policies.
    The  workshop  brings together  research scientists, epidemiologists.
engineers,  and microbiologists from government and academe to discuss and
exchange information  on outbreak investigations, analytical  procedures, and
water supply engineering, surveillance and regulatory  activities.   Improved
communication is needed  among  the  various disciplines and agencies that
share responsibilities  in the investigation  and  prevention  of waterborne
    Plenary sessions were developed to provide participants  with  basic
concepts  and knowledge  of epidemiology, water  supply  engineering, and
clinical and water sample collection and analyses.  Examples of several recent
outbreak investigations  serve to reinforce this  knowledge  and provide an
understanding of the investigative process.  More detailed discussions of each
of these  areas wd! be presented in the breakout sessions.  Articles based on
the presentations will be published in a reference  volume which will be made
readily available to assist in the investigation of outbreaks.
    The  last part of the workshop is devoted to identifying research,  training.
and  other  requirements  to prevent waterborne outbreaks and improve their
recognition, investigation, and  reporting.   These  recommendations are
developed  through panel discussions  and audience participation and
published in a separate report.

Review  of Current Waterborne  Diseases.  GUNTHER  F. CRAUN (Health
Effects Research Laboratory. US Environmental Protection Agency,  Cincinnati.

     The reporting of waterborne  disease outbreaks has been and continues to
be voluntary.  Statistical  data are available on water outbreaks reported in the
United States since 1920.  These data are compiled from information obtained
from the scientific  literature and through the assistance of  state and loca!
health officials and engineers.  The  Environmental  Protection Agency and
Centers for Disease Contro! have cooperated in the investtgation and reporting
of waterborne outbreaks  since 1971.

    The  incidence of waterborne disease in the United States  has declined
from about eight cases per 100,000 person-years during 1920-40 to four cases
per 100.000  person-years during 1971-80.  The number of outbreaks reported.
however, has  not declined,  and more waterborne outbreaks were reported
during 1971-85 than in any previous 15 year period since 1920.  During 1971-
1985. 502 waterborne outbreaks and 111.228 cases of iHness were reported m
49 slates and Puerto Rico and  the Virgin Islands.  Almost three  fourths of
these  outbreaks were  caused by use of contaminated, untreated  or
inadequately treated  groundwater and  surface water. Waterborne diseases in
the United States are transmitted by the fecal-oral  route of exposure, and it is
important to  recognize that contaminated drinking water is only one  of several
sources of infection.  An epidemiologic investigation is necessary to establish
the probable cause of illness.  Giardia  lamblia  has been the most commonly
identified pathogen  in waterborne  outbreaks since 1971, and contaminated
drinking  water is a  significant source of infection for giardiasis.    Human
sewage contamination was primarily responsible for the traditional waterborne
diseases such as typhoid fever; however, for  several  of the more recently
identified waterborne diseases such as giardiasis,  wild and domestic animals
have also been found to be an important primary or intermediary source.
    Current drinking water  regulations  are  insufficient  to prevent  the
waterborne transmission of infectious disease, as outbreaks  have occurred m
water systems that have not exceeded current regulations for coliforms  and
turbidity. Analysis of data from outbreaks in surface water systems shows the
need  for filtration  in  addition to disinfection  to  ensure the removal  and
inactivation  of waterborne pathogens,  especially  protozoa such  as Giardia.
Properly designed and  operated filtration plants can  clarify water  making
disinfection more effective and can remove microorganisms  leaving fewer for
the disinfection barrier to inactivate.
    It is important to continue waterborne disease surveillance  and improve
the reporting of outbreaks so that information  will be available on  their causes.
To  be  effective in  reducing  waterborne  disease risks,  regulations  and
surveillance  activities must be based on outbreak experiences.
    This is an abstract of a presentation and does  not necessarily reflect EPA

The 1986 SDWA Amendments and Drinking Water Regulations. PAUL S
BERGER (Microbiologist,  Office  of   Drinking Water. US  Environmental
Protection Agency.  Washington, DC)  and STIG  E.  REGLI (Environmental
Engineer, Office of  Drinking Water, US Environmental Protection Agency,
Washington. DC).

    The Safe  Drinking Water Act Amendments passed  by Congress in 1986
require the  US Environmental  Protection  Agency  (EPA) to  develop drinking
water  regulations for 83 contaminants, including total  coliforms,  turbidity,
heterotrophic  bacteria, viruses, Giardia,  and Legionella.  In response,  the
EPA's Office of Drinking Water  proposed two regulations  on November 3.

1987: the Total Coliform Rule and She Surface Water Treatment Rule (SWTR).
The  proposed total  coliform  regulation significantly  revises  the existing
regulation.   Coliform limits (maximum  contaminant levels  or  MCLs)  have
traditionally been based on density, but  in the proposed rule would be based
on the presence or  absence of detectable coliforms m a 100-ml  sample of
water.  The proposal sets  limits on the percentage of water samples  which
could be coliform-positive, and specifies the minimum  monthly monitoring
frequency, required analytical methodology, and the response necessarywhen
a sample is found to  be coliform-positive.
    The proposed SWTR includes a) criteria under which filtration would  be
required and procedures by which the State would determine which systems
must install filtration,  and b) disinfection requirements for water systems using
surface water  sources.   The  filtration  and  disinfection  requirements are
designed to protect against the potential  adverse health effects of exposure to
Giardia, viruses, Legionella,  as well as many other  pathogenic organisms.
The  SWTR also controls the levels of  heterotrophic bacteria and turbidity.
Later. EPA  will publish additional regulations requiring groundwater systems to
disinfect their water  before distribution to customers and  establish  criteria  by
which a water system could avoid disinfection  practice.

Surveillance for Waterborne Illness  and  Disease  Reporting:  Federal
Responsibilities  and  Requirements.  ROBERT  V.  TAUXE, M.D.. M.P.H.
(Enteric Diseases Branch, Division of Bacterial Diseases. Center for Infectious
Diseases. Centers for Disease Control, Atlanta, Georgia.)

     Since  1971. the Centers for Disease  Control  m collaboration with the
Environmental   Protection Agency  has collected and  reported  data on
outbreaks of illness associated with water intended for drinking. The purposes
of this surveillance are:  1) to determine  trends in the incidence of waterborne
diseases in the United States, 2) to characterize the epidemiology  of
waterborne diseases, 3)to disseminate information on waterborne disease, and
4) to provide a basis for evaluating the  effect of disease  control  efforts.  For
each outbreak, data  are collected on the clinical illness, on the epidemiologic
data which implicated drinking water as  the vehicle, and on the results of the
investigation of the water supply system. These data are reported  voluntarily
by state agencies on a standard form.  Interpretation of these data is limited
by under reporting, and by the differences in  interest and  resources that  state
and  local health agencies have for waterborne disease.   During the  period
1971-1985,  there has been  a decrease  in  outbreaks  due  to  the classic
waterborne pathogens hepatitis A, Salmonella typhi, and Shigella; at the same
time Giardia, Cryptosporidium, Campylobacter and the Norwalk agent  have
emerged as important  waterborne pathogens.   In this time  span, the  most
frequent type   of water  supply  system  involved in  outbreaks  was the
community system;  the most frequent  identified defect in the  water supply
was  a deficiency  in  water  treatment.  More complete  epidemiologic
investigations, advances in laboratory techniques, and standardized reporting

of waterborne disease  outbreaks  will augment the national  surveillance  of
waterborne disease outbreaks.

 Epidemiologic Methods for the Investigation of Waterborne Diseases
RICHARD  L.  VOGT,  M.D  (State Epidemiologist.  Vermont Department  of
Health. Burlington).

I.Objectives of a waterborne investigation
      A. First: to protect the  health  of  the people at  risk by stopping
        waterborne spread of the agent
      B. Second: to determine the cause of the outbreak
      C. Third:  to correct existing defects in the water distribution system
      D. Fourth:  to learn about new aspects of waterborne disease
      F. Other
II.Information sources
      A. Health care providers
      B, Water supply operators
      C.  Local health departments
      D.  News media
      E.  Disease reporting system
      F.  Other
III. Steps to an investigation
      A. Case definition
      B. Organization of data
        1.  Person
        2.  Place
        3.  Time
      C. Hypothesis test: is water responsible?
      D. Epidemic curve
      E. Types of study  designs
        1.  Population studies
        2.  Follow-up studies
           a. Random-digit telephone survey
           b. Door-to-door household survey
           c. Cohort studies
        3.  .Case-control studies
           a. Cases identified in hospitals, doctors' offices, health department
           b. Controls selected from similar settings
      F. Analysis of data
        t.  Univariate analyses
           a. Cohorts (2x2 tables, attack rates, relative risks)
           b. Case-control studies (odds ratios)
           c. Household sampling (t-tests, non-parametic analyses)
        2.  Dose-response relationship
      G Other innovative methods

        1. Small cohort study
        2. Environmental sample survey
     H. Analyses for etiologic agents
        1. Bacterial
        2. Parasitic
        3. Viral
        4. Serology  studies
     I.  Investigation caveats
        1. Mixed results with special surveillance for outbreaks
        2. Exposure information
          a. Decay of information over time
          b. Water  preference data
          c. Questionnaire response vs. diary
          d. Diarrhea as a confounding factor
        3. Evaluation household index cases or early cases in an outbreak if
          widespread secondary transmission occurs
        4. Difficulty  in  choosing  comparison  populations (problems  with
          a. Communities may not be similar in follow-up studies
          b. Comparison populations may be dissimilar in case-control
          c. Confounding may be evaluated after completion of the study

Principles of Water Filtration.   GARY S. LOGSDON (Chief. Microbiological
Treatment  Branch,  Drinking Water  Research  Division,  Risk  Reduction
Engineering  Research Laboratory, USEPA, Cincinnati. OH).

    Three processes generally used to filter water are  diatomaceous  earth
(DE) filtration; slow sand filtration;  and  coagulation, generally in conjunction
with other pretreatment, followed  by granular media, rapid rate  filtration. DE
filters employ a thin (1/8 inch or greater) layer of fine,  porous filtering material
and generally remove particles by the straining  mechanism.  Slow sand  filters
employ a bed  of sand about 3 to 4  feet deep,  and remove  particles by
attachment mechanisms. In addition, larger organisms living in the slow sand
filter bed prey  upon  smaller organisms.  Rapid rate filters employ beds of
media generally 2 to 3 feet deep.  A single filtering  material sometimes is
used.  Often two or three different kinds of media, having  different size ranges
and  specific gravities, are  used.   Removal occurs mainly by attachment of
particles to grains of  filtering material.
    Mechanisms  causing particles to  attach to grams  oi  filtering material
include interception,  sedimentation, and  random  (Brownian motion).   The
effect of these mechanisms varies with media grain size, particle size, filtration
rate, and some other factors.  An especially important factor is the  degree of
"stickiness" or instability of colloidal particles. When  a colloid touches a gam
of media, it is more likely to stick to the gram if  the surface charge of a colloid
is near neutral,  rather  than  highly electronegative or highly electropositive.
Thus pretreatment that accomplishes particle destabilization is very  important

in  rapid rate filtration.   Cathionic polymers  or salts  of aluminum or iron are
used  to coagulate and  destabilize colloids.   Biological activity in slow  sand
fitters is thought  to cause production  of excellolular polymers that promote
particle destabilizatton.  This paper shows how filter design concepts, such as
media size, bed depth, and filtration rate, are related to filtration principles

Principles of Drinking Water Disinfection for Pathogen Control.  JOHN
C.  HOFF {Research  Microbiologist. Microbiological  Treatment  Branch.
Drinking Water Research  Division, Risk Reduction  Engineering  Laboratory,
U.S. Environmental Protection Agency,  Cincinnati. OH).

    The pathogens that must  be inactivated by drinking water  disinfection
comprise  a  diverse group of microorganisms (bacteria,  viruses,  protozoans)
with regard  to occurrence,  size, mode of existence,  and resistance  to
disinfectants.   Of the  many chemical  and physical  disinfecting  agents
available,  only a few have been widely applied for large  scale drinking  water
treatment  in the U.S.  or  other countries.  These include free and combined
chlorine,  chlorine dioxide and ozone.  The kinetic nature of microorganism
inactivation  by disinfectants  was described many years ago  and  much
information  has  been  developed  on  the comparative  resistance  of
microorganisms  and  the  comparative effectiveness of  disinfectants.   Only
recently have efforts been made to apply this information to the development
of scientifically based drinking water disinfection requirements. This approach
is  based  on use of  disinfectant  concentrations (C) and contact  times  (t)
required for the inactivation of target pathogens  under various conditions  of
water pH  and temperature.  While the effects of temperature increases are
consistent with all disinfectants and pathogens, i.e. inactivation rates increase
as temperature increases, pH  effects vary depending on the disinfectant and
target pathogen.  The influence of these factors and others including turbidity
and mixing efficiency will be discussed.
    This is an abstract of a presentation and does not necessarily  reflect EPA

Environmental Sampling, Methods, Limitations, and Data Interpretation.
JOAN B. ROSE (Departments of Microbiology and Immunology and Nutrition
and Food Science. University of Arizona. Tucson).

    As  the  role  of contaminated water  was   being  elucidated  m  the
transmission  of viruses (enteroviruses,  hepatitis A  virus.  Norwalk  virus
rotavirus), parasites  (Cryptospondium  and  G/ardia).  and  bacteria
(Campylobacter). methods were under development for the detection of these
microorganisms in water.  Filtration methods have developed for detectio of
both the viruses and parasites.  This includes collection of large volumes of
water (400L)  after  which  the  filters are processed  and  the  concentrates
clarified. The samples  are assayed on cell culture and using microscopic and
immunofluorescent  techniques for  viruses and parasites,  respectively.   For
bacteria such as  Campylobacter,  filtration methods  are  also  utilized  (1L
samples) followed by enrichment and selective culture techniques.
    At issue with any of these  methodologies is the effect of water quality on
the recovery  efficiencies.   Other limitations include: 1) lack  of  cell culture
techniques tor viruses such as the Norwalk virus, 2) inability to assess viability
of the protozoa and 3) the detection of non-cultivatable and stressed bacteria.
    In most  cases during the investigation of  a waterborne  outbreak  the
etiological agent is not recovered from the suspected water source.   This
pattern, however,  is gradually changing. Coxsackie B viruses and hepatitis A
virus  were iso-tated from  an outbreak  of gastroenteritis where the hepatitis
infections  did not appear in the community until  several weeks later.  During
one of the largest waterborne outbreaks, caused by Cryptospondium, oocysts
were isolated  from drinking  water  following conventional  treatment.
Campylobacter and particularly Giardia. have been detected in the drinking
water during several waterborne outbreaks.
    Recommendations for environmental  sampling include    1) Immediate
collection  of the water samples upon recognition of an outbreak. 2) Collection
of a  minimum of  4QOL for viruses and  parasites and 11 for bacteria.   3)
Collection of  three replicate samples of an individual well or 8 to 10 samples of
the treated water (distribution system and deadend mains). 4) Collection  and
assay for a broad range of microorganisms.

Investigation  of  Outbreaks  Emphasizing  Engineering/Epidemiology
Interactions. EDWIN  C.  LIPPY, P.E.  (Engineer  Director,  US  Public Health
Service, Retired; Self-employed, Consulting, Cincinnati. OH)

    The on-scene investigation and analysis  of water  systems  that were
subjected to  waterborne disease outbreaks provided numerous experiences
which are discussed during  this presentation.    The  information  developed
during  investigations,  and  proving  useful  to the  engineer  and  the
epidemiologist, are presented  through the  use  of  examples  from actual
disease outbreaks

Epidemiologic Characteristics  of Waterborne Cryptosporidiosis.
DENNIS  D. JURANEK  (Chief.  Epidemiology,  Parasitic Diseases  Branch
Division of Parasitic Diseases. Centers for  Disease Control. Atlanta. GA.).

    Cryptospondium. an intestinal protozoan parasite transmitted by the iecai-
oral  route,  is  a well-known  cause of diarrhea m  animals  but  has  been
recognized only recently as a cause of diarrhea  in humans.  The parasite first
gamed national attention as a cause of severe,  incurable diarrhea  m patients
with  AIDS   More recently  it has been  recognized  as important cause  of
diarrhea in  persons who have no obvious  immunodeficiency.  Risk factors for
infections include:  1) exposure to stool of  infected animals (especially calves).
2} exposure to diaper-aged children who attend  day care centers, 3) anal-oral
sexual practices, and 4) drinking contaminated water.
    Municipal  waterborne  outbreaks  of Cryptosporidiosis were unrecognized
until  1984 when a sewage-contaminated well was implicated in an outbreak  of
diarrhea in Braun Station,  Texas.   In  January of 1987. CDC m  collaboration
with the Georgia Department of Human Resources, EPA.  and the University  of
Arizona had the  opportunity to investigate the first waterborne outbreak
involving a surface water  supply and a modem water treatment facility that
utilized rapid sand filtration.  The investigation revealed that Cryptospondium
oocysts were  able to  breach  the  water treatment  facility  which  was  in
compliance with EPA and State of Georgia limits for chlorine residual, coliform
bacteria, and turbidity levels.  An estimated 13,000 residents (40% of people
drinking municipal water)  become ill.  The major features that distinguish
Cryptosporidiosis from giardiasis are 1) Cryptospondium's small size (3-4 urn)
which requires better filter performance for removal than for Giardia cysts (8-
12 um). 2) Cryptospondium's  high  resistance  to  disinfectants, e.g   it  can
survive chlorine concentrations of 40,000  mg  L or  higher. 3)  the  greater
potential for water contamination  by the  feces  of  Cryptospondium  infected
animals. 4} Cryptospondium's higher infection rate in the exposed population.
e.g. 40% for Cryptospondium vs. 1% to  10% for Giardia. 5) a higher  illness
rate  among those  infected, e.g.  95% for  Cryptospondium vs. < 50o for
Giardia, and  6)  the  absence of  antiparasitic drugs  to  treat  the  Cryp-

Troubleshooting  an  Existing Treatment Plant.  GARY  S.  LOGSDON
(Drinking Water Research Division,  Risk Reduction  Engineering  Research
Laboratory. USEPA, Cincinnati.  OH). LEWIS  MASON (Carrollton  Water
Treatment  Plant. Carrollton, Georgia) and  JAMES B.  STANLEY. JR. (Keck  &
Keck. Atlanta. Georgia).

    During  January and  February.  1987,  a  waterborne disease outbreak
caused by  Cryptospondium occurred in Carrollton, Georgia.   Several thousand
persons were  estimated to have been ill  with gastrointestinal disease at this
time   An engineering investigation  was carried out at  the Carroliton treatment.
plant  during the first week of February   The  paper describes the evaluation
experience and  presents the findings  ol the filtration   plant evaluation

experience and  presents  the  findings of the filtration  plant evaluation, the
recommendations  made,  follow-up actions  by the utility, the  costs of the
improvements, and the results with respect to turbidity of the filtered water
    The 8 MGD Carrollton filtration plant actually consists  of two side-by-side
4 MGD conventional  treatment trains that are hydrauiically  separated  Two
banks of five filters each are located in the  filter building.  The plant can  be
operated only at 4 MGD or 8 MGD.
    The  plant  evaluation revealed  a temporary  absence  of mechanical
flocculation. during a changeover from horizontal shaft reel-type floccuiators to
vertical shaft turbine floccuiators.  Equipment for monitoring filter behavior was
inadequate  or  not  functional.    Filters were  sometimes restarted  without
backwashmg after being operated and shut off.
    At the  conclusion  of the  evaluation, a list  of recommendations was
presented. These  dealt with raw water, rapid mix, chemical feed, flocculation.
sedimentation, filter operation, filter monitoring, the laboratory, the distribution
system  and human resources.  These are explained in  the paper.  Follow-up
actions  are also described, and  include facilities repair, renovation, and
improvement and operating procedure changes.
    The capital improvements,  made at a cost of $277.000, have resulted in
production of filtered  water turbidity  in the range  of 0.03  to 0.08 NTU,  for a
monthly  average.   Before the  outbreak,  the monthly average  filtered  water
turbidity tor December. 1986, was 0.52 NTU. A substantial improvement has
been attained at a reasonable cost.
    This is an abstract of a presentation and  does not necessarily reflect EPA

Chronic  Diarrhea in  Henderson  County, Illinois.  JULIE PARSONNET
(Enteric Diseases Branch, Division of Bacterial Diseases, Centers for  Disease
Control.  Atlanta, GA)  and  SUSAN  TROCK  (Division  of  Field  Services.
Epidemiology Program Office, Centers for Disease Control, Springfield. IL).

    In July-August 1987, an  outbreak of chronic diarrhea affected 72 people in
rural Henderson County,  Illinois.  Illness was characterized  by non-bloody
diarrhea (median 12  stools/day), urgency (100%),  fecal  incontinence (64-i)
and weight loss (mean 10 IDS).  Nine patients were hospitalized; none died.
There was no clinical improvement with  antimicrobial therapy.  Small bowel
and colomc biopsies performed on selected patients were  not diagnostic.  No
bacterial, mycobacterial, viral or parasitic known to be enteropathogenic  were
detected in stools.
    Case-control   studies  implicated  a  restaurant  (p = 0.0001)   and.
subsequently, the  wel!  water served in the restaurant (p = 0.04, OR = 9.3)  as
the vehicle of transmission. A cohort study of truck drivers  who frequented
the  restaurant  demonstrated a dose-response relationship  between  water
consumption and  development of illness.  There  were numerous sanitation
violations within the  water  distribution  system which  could possibly   have
permitted  water contamination; however, no  pesticides,  herbicides, heavy
metals, mycobactena. viruses or parasites were detected in the water.

    This is the first outbreak of chronic diarrhea linked to untreated water  A
large  outbreak in Brainerd.  Minnesota in  1984-1985 resulted  from drinking
unpasteunzed milk  Reports of continued sporadic cases m the area suggest
a possible endemic focus in the Midwest.

Waterborne  Giardiasis in  Pittsfield,  Massachusetts: Epidemiologic
Perspective.  GEORGE P.  KENT.  M.D. (Department of Medtcme.  Stanford
University School of Medicine. San Jose. CA: formerly with the CDC).

    in the period  November  1, 1985 to  January  31.   1986. 703 cases of
giardiasis were reported in Pittsfieid, Massachuselts (population 50.265).  The
community obtained its water from two main reservoirs (A and  B) and an
auxiliary reservoir (C).   Potable water was  chlorinated but not filtered.  The
incidence of  illness peaked approximately two weeks  after the  city  began
obtaining  a major portion of its water from reservoir C.  which had not been
used  for three years.   The attack rate of  giardiasis for residents of areas
supplied by reservoir C was 14.3''1000, compared with 7.0 1000 in areas that
received no water from  reservoir C.  A case-control study  showed that persons
with giardiasis were  more likely to be older and to have drunk more municipal
water than household controls.  A community telephone survey indicated that
over 3.800 people could have  had diarrhea that might have been  caused by
Giardia, and 95 percent of households were either using alternate  sources of
drinking  water or boiling municipal  water.   Environmental studies identified
Giardia cysts  in the water of  reservoir C. Cysts were also detected in the two
other  reservoirs  supplying  the city, but  at  lower  concentrations   This
investigation highlights  the risk of giardiasis  associated with unfiltered surface
water  systems.(Abstract excerpted  from  the  article  entitled.  "Epidemic
Giardiasis Caused  by  a Contaminated Public Water Supply." GEORGE P
KENT,  M.D..  et  al. American Journal of  Public Health  1988.. 78139-143
reprinted with permission of the American Public  Health Association.)

An Outbreak of Ice-related Norwalk Gastroenteritis: Pennsylvania and
Delaware. JAY R. POLINER (Director, Eastern New York Occupational Health
Program), ROBERT CANNON (Medical Epidemiologist.  Center for Infectious
Disease. Centers for Disease Control).

    Between September 19  and  25, 1987.  a  series  of  outbreaks  of
gastroenteritis  occurred  among  participants  and   spectators  at an
intercollegiate  football  game in Philadelphia and a  museum fundraiser in
Delaware.  A field survey of two of these groups impliated ice consumed m
carbonated and alcoholic beverages (Relative risk =  4.3. with 95<> confidence
interval of 3.4 to  5.4).  Serological testing of students identified Norwalk  agent
as the causative agent
    The ice.  distributed in  Pennsylvania.  Delaware,  and New Jersey, was
traced to a manufacturer in southeastern  Pennsylvania whose  wells had
flooded following a  torrential rainfall on September  8.   From the limited ice

production  records available and  records  of  ice  consumption  by different
groups, we  estimated that  5000 cases  may  have  occurred during these
    This is one of the fargest outbreaks  of  Norwalk  gastroenteritis  in recent
years.  Ice has rarely been implicated in  outbreaks of gastroenteritis, and the
investigation and  prevention of  ice-related outbreaks can be  complicated by
lack of labelling and variations in manufacturing  Assuring safe watr supplies
for ice  manufacturing may prevent further  outbreaks.

Waterborne  Giardiasis  in  Pittsfield, Massachusetts: Engineering
Perspective. JOHN  J. H1GGINS  (Regional  Director,  Massachusetts
Department of Environmental Quality Engineering, Springfield).

    In  December of 1985, the  Massachusetts Department of Public Health
received reports  of a large number  of  cases of giardiasis in  the greater
metropolitan Pittsfield area.  State, local, and federal agencies responded and
were able to determine that the outbreak  resulted from a unique  combination
of construction activities,  equipment malfunctions and  weather conditions.
    Discussed are the  series  of events that  led up to the outbreak,  the
investigation which was conducted, and the steps  which have been taken to
prevent further occurrences.

Development of Data  Collection  Instruments:  Questionnaires  and
Interview Schedules. CHARLOTTE A. COTTRILL (Health Effects Research
Laboratory. EPA,  Cincinnati, Ohio).

    Information obtained  from interviews and self-administered questionnaires.
is key to  the investigation of waterborne  disease  outbreaks.   Obtaining
accurate information from  interviews  with  cases and  persons at risk  is
essential in determining if  a water-borne outbreak  is occurring and in  the
actual  investigation  of an  outbreak.   This discussion will  attempt  to relate
general principles of social/behavioral science and  survey  research to  the
investigation  of outbreaks by considering these investigations as continuous
research processes involving two broad stages, the formulation stage and the
research state.
    The initial stage is labeled the "formulation" or exploratory stage because
this is  when a vaguely defined situation becomes more clearly defined leading
to the  decision of whether or not to conduct an investigation.  The information
obtained in this  stage also provides  important background for  defining  the
problem and  developing the research  design  and  the necessary  forms.
including questionnaires  and interview  schedules and guides. Therefore, the
 "formulation"  stage gives rise to  more systematic and  rigorous  investigation
which  this discussion will treat as the second stage.
    During the "formulation" stage, it is likely that interviews will be conducted
to obtain more detailed information about  the situation. This may require more
 flexibility  than afforded  by  a standardized questionnaire.  The  "focused in

depth" interview is particularly well-suited to this type of task.  Because of its
flexibility,  the focused  interview can provide  more detail  than a  highly
structured interview  because  it gives both the interviewer and respondent
more latitude. This method may also be helpful because the respondent may
raise issues and questions that the investigators  have not considered or were
    This discussion will  address  the development and usage of interview
guides in the formulation  stage of  a  suspected waterborne disease outbreak.
proceeding  to  the  development  of  structured  interview schedules  and
questionnaires for usage in the "research or investigation" stage.  The latter
part of  the discussion  focuses on  questionnaire  construction and question
writing.  It attempts to provide a concise overview that includes:  (1) choosing
the mode  of administration;  (2)  writing questions; (3)  common errors in
question writing; and (4) formal characteristics of questions.  The emphasis is
on the development of well designed questionnaires that will contribute to the
collection of  accurate and complete  information  and facilitate data reduction.
analysis, and interpretation.

Data Analysis: Estimating Risk.  NEAL D. TRAVEN (Instructor. Department
of Epidemiology, Graduate School of Public Health, University of  Pittsburgh.
Pittsburgh PA).

    Statistical analysis of  questionnaire data collected from persons who may
have been  exposed  to  suspected disease-causing  microorganisms  is an
essential component of  the  investigation of waterborne disease  outbreaks
This paper reviews some  important aspects  of epidemiologic data analysis as
they apply to waterborne outbreak investigation.
    Among the topics discussed are  point estimates of risk  (relative risk, odds
ratio, and attack rate), confidence intervals of  the risk estimates, and  the
interrelationship  between  sample  ssze   and  statistical power  Where
appropriate,  illustrative  examples  are  taken  from  data  presented m
investigation  reports of actual waterborne disease outbreaks.
    One step removed from these statistical'analytic considerations are  the
issues of reliability and validity of the information on which the epidemiologic
data analysis is carried out. Data of uncertain reliability, whether due to poorly
designed questionnaires, unclear responses, or myriad other reasons, can bias
the analytic results of an outbreak  investigation.  The influences of such  bias
and non-reliability on risk estimation are discussed.

Data  Interpretation:  Differences  Between Outbreak  Investigation  and
Research  Epidemiology. NEAL  D.  TRAVEN  (Instructor, Department  of
Epidemiology. Graduate  School of Public Health,  University  of  Pittsburgh.
Pittsburgh PA).

    Much of the early  history of epidemiology, such as Snow's  work on
cholera,  revolved around investigation  of  outbreaks of  acute infectious
diseases.  Outbreak investigation  of waterborne diseases still owes  much  to
those methodologies developed  in  the 19th  and  early  20th centuries.
Improvements in sanitation  and  drinking water  purification, advances  in
microbiologic identification of pathogens, and the wide availability  of vaccines.
antibiotics, and medical care have vastly decreased the number and  scope  of
such outbreaks in industrial and post-industrial societies. Since World War  II.
then,  the research focus of epidemiologists  has  turned increasingly to such
chronic  conditions as  heart disease, cancer, diabetes mellitus, and a host  of
    In a research environment where Koch's postulates  are of diminished
utility, epidemiologic study designs and analytic methodologies have  been
developed to examine such  multifactorial diseases.   Instead of "causes."
epidemiologist now search for "risk factors" of disease. Much attention is paid
to associated diseases, the influence of health behaviors,  environmental and
occupational exposures, genetic predisposition, and many other confounding
or  interaction factors.    Selection of  appropriate  study  subjects  is of
overwhelming importance in  such  research.  In  addtion,  the  purview of
epidemiologic methodology  has  now expanded to  include such fields  as
controlled clinical trials and evaluation of health programs.
    In this  paper, these newer  epidemiologic  methodologies  are briefly
contrasted with those  of outbreak  investigation. Possible avenues for analytic
epidemiologic research in the drinking water field are discussed as well.

Emergency Response and Control  Measures.  GAYLE J. SMITH (Bureau
of Drinking Water/Sanitation, Utah  Department of Health. Salt Lake  City).

    Effective response  and control measures  must  be both  timely  and
appropriate.  Often attempts at timeliness cloud or minimize considerations of
appropriateness  and vice versa.   What are the relative  trade-offs  between
these two considerations? How  can  these considerations compliment each
    Many  response  options are  available for any  given  emergency.   The
available  on-hand data  may  be insufficient to clearly define the  most
appropriate responses.  Yet, as public health officials, we  must take action to
protect  the  health of our citizens!  How much data do we wait for before we
take action? Recognizing that we must frequently act without definitive data,
what  actions maximize  public health protection and, at the same  time,

minimizes public health risk if the cursory diagnosis  of the emergency is  m
    Involvement of the news media and politicians in emergency  situations
often necessitates spending scarce resources on  non-vital but highly urgent
responses.  How does the public official satisfy the urgent, less vital neeas
that cannot be ignored and yet maximize resource dedication  to vital public
health protection actions?
    Appropriate actions may change as additional data more clearly define the
characteristics of the outbreak  emergency.   Are  public officials always
objective and willing to modify actions to correspond with the dictates of new
    The relative success or failure of emergency  responses hinge on  clear.
concise and appropriate communications!  Is there a spokesperson for each
emergency?  Does the public know  who this person is and how to access
him/her?  What communication roles should the State  and  local  health
departments fill to compliment the communications network?  Who speaks to
the news media? Who interfaces with the politicians?
    The appropriateness of the  emergency response and  control measures
are extremely important, not only to minimize adverse public health impacts,
but to reinforce in the public (and political) mind the value of a well disciplined
and competent public health team.

Surface Water Source Protection.  JOSEPH  L. QUICKER (Water Quality
Director, Portland Water Bureau. Portland, OR).

    Obtaining the best possible water quality is the goal o1  any  surface  water
service protection program.  Described are  the process by which a surface
water source protection program  can be  developed, the threats  that are most
commonly found to water quality in surface supplies,  the  general means to
control those threats, and  some of the upcoming problems and needs in  the
field of watershed protection.  The City  of Portland's  Bull Run  Watershed is
used to illustrate application of some of these concepts.

Distribution System  Protection. PETER C. KARALEKAS, JR.  (Chief. Water
Supply Section. U. S. Environmental Protection Agency, Boston, MA).

    Sanitary defects in the distribution systems of  public water systems have
caused a number of waterborne disease  outbreaks.   Cross  connections.
inadequate disinfection  of new  water mains, open  storage  reservoirs,  and
corrosion  of  household plumbing and  service  lines  are  among  the  most
common reasons cited as the cause of distribution system related outbreaks.
    There are a number of mechanisms available  to regulatory  agencies and
public  water supply systems to detect and eliminate these  deficiencies
Sanitary  surveys, regulations, plumbing  code enforcement, cross connection
surveys and  a  more recent innovation,  namely, the  certification of backflow

prevention  device testers  can be  used  to  deal  with distribution system

Evaluating  Treatment Plants  for Particulate  Contaminant  Removal.
GARY S. LOGSDON (Chief. Microbiological Treatment Branch. Drinking Water
Research  Division,  Risk  Reduction  Engineering  Research  Laboratory.
U.S.E.P.A.. Cincinnati, OH).

    Evaluation of water filtration plants is a  multi-stage process that should
begin  with careful  planning.  The  recommended  procedure  includes
determining project goals, reviewing available  information, and evaluating plant
hydraulics  and flow  patterns.   Processes that should be  evaluated include
chemical feed selection and control, rapid mixing,  floccuiation, sedimentation
and filtration.  Laboratory and pilot facilities  should be included in the eval-
    Water  filtration must be evaluated in  the context of the  entire  treatment
plant and its operation, because attaining effective pretreatment is essential to
successfully filtering water. The steps listed and described in  this paper place
a  strong emphasis  on  the  pretreatment  processes.    No standardized
procedure  for chemical dose selection and control exists, so treatment plant
practice is  quite variable.  Doses may be set by use of jar tests, zeta potential
and streaming current instruments,  pilot filters, or by other means.  Chemical
feeding practices also vary, and some techniques may be much  less efficient
than others. Therefore, a careful evaluation of pretreatment is imperative.
    The hydraulics of the  treatment plant are important, and strongly influence
performance during  floccuiation  and  sedimentation.  Here  the  uniform
distribution of flow is important, and plug flow  is very desirable.
    Filter operation should be evaluated to determine if the most appropriate
procedures are being followed. Frequent and  sudden rate changes and restart
of dirty  filters without backwashing  should be  avoided because  of  the
deleterious effects these actions have  on  filtered water quality.   The filtration
process should be carefully monitored in order for the operator to  be in control
at all times. The quality  of laboratory data and the ways in  which  operating
data are used to manage the filtration plant should be reviewed.
    This paper concludes with some examples of plant improvements.
    This is an abstract of a presentation and does  not necessarily reflect EPA

Evaluation of Disinfection Processes and  Facilities. GARY S. LOGSDON
(Chief, Microbiological Treatment Branch, Drinking Water Research Division,
Risk Reduction Engineering Research Laboratory, USEPA, Cincinnati. OH).

    Evaluation of disinfection is  a key  aspect  of  water treatment plant
evaluation  during an  outbreak.   This work  could be accomplished  in four
phases, including review of plant records, evaluation of disinfection equipment.

inspection  of  physical processes,  and review of chemical  monitoring  and
quality control as related to disinfection.
    Review of operating records can be a useful way to gain an understanding
of water utility practice. The data on chemical purchases should be consistent
with data on water production and chemical dosage.  Plant records also should
indicate the extent to which disinfectant residual is  carefully controlled or
allowed to  fluctuate.   With adequate data, the engineer reviewing the facility
may be able to gain an understanding about the disinfectant demand of the
raw water.
    An evaluation ol equipment should be undertaken to develop information
on  the  state  of repair of the equipment  and  on availability of back-up
equipment.   Chlorine  feed  may  be  adjusted  manually, paced with flow.
adjusted based on residual, or based on both flow and  residual.  The extent of
monitoring  equipment should be noted, as well as the availability of a back-up
power supply, especially for systems in which water flows to distribution by
    Physical processes are important.   For free chlorine,  chloramine. and
chlorine dioxide, the disinfectant chemical should be dispersed as thoroughly
and  instantaneously  as possible into the water.   After the initial mixing of
chemical disinfectant and  water, a  period of contact time should be attained.
For the above-mentioned  chemical  agents uniform contact time  for all water
treated  is best achieved in  plug flow, either in a transmission main or in  a
serpentine  contact basin.   Rate of flow influences residence time, so flow
metering capability is needed.  Except for long pipe-lines, contact time is best
determined by conduction  tracer studies.
    Quality control  of all chemical  measurements  is important    Good
laboratory QAQC procedures should be followed when disinfectant doses and
disinfectant residual measurement is not always easy or straightforward  The
advice of a chemist on exactly what analytical procedures are appropriate ioi
specific circumstances may be needed.
    Disinfection  needs to  be evaluated carefully, because it  is an important
process in  water treatment.  Merely adding  some disinfectant chemical to  a
water dose not necessarily  render it  potable.   Each  of  the aspects of
disinfection mentioned in this paper  is important and should be given a careful
and thorough evaluation.
    This is an abstract of a presentation and does not necessarily reflect EPA

Determination of Ct Values. ROBERT M.  CLARK (Director, Drinking Water
Research  Division,  Risk Reduction Engineering  Laboratory.  U.S.
Environmental Protection Agency, Cincinnati, Ohio).

     The Amendment, to  the  Safe  Drinking Water Act  require  that EPA
promulgate primary  drinking water regulations (a) specifying criteria under
which filtration would be  required,  
lamblia, viruses, Legionella. heterotrophic plate count bacteria, and turbidity.
If a utility,  in addition to meeting  other  requirements, can demonstrate that
through effective disinfection, it can reduce  Giardia levels by 99.9%. then it
will be exempted from the surface water filtration requirement.
    To demonstrate  that  the system  ts  achieving a  specified  percent
inactivation, the system  would monitor  disinfectant  residual(s),  disinfectant
contact time(s), pH, and water temperature, and apply their data to determine
if the  Ct [the product of disinfectant  concentration (mg.L) and  disinfectant
contact time (minutes) value equafs or exceeds CT values specified in the Sur-
face Water Treatment  Rule {SWTR).  Ct values necessary  to achieve 99.9
percent inactivation of  Giardia cysts  -by various disinfectants  and  under
various conditions  are specified in EPA's proposed  Surface Water Treatment
Rule and Ct  values recommended for filtered systems, depending upon the
appropriate  level of inactivation,  will be  specified  in the SWTR Guidance
Manual. Therefore, understanding Ct values  and their significance  is critical to
understanding the  SWTR.  The Ct concept is based on an empirical equation
stemming from the early work of Watson and is expressed as:

             K =  C"t                              (1)

where       K = constant for a specific microorganism exposed under
             specific conditions.

             C = disinfectant concentration in mg'l
             n = constant, also called the  "coefficient of dilution"
             t = the contact time, required for a fixed percent inactivation in
    For purposes of this paper the discussion  will  focus on chlorine
disinfection.  The  destruction of pathogens by chlorination is  dependent of a
number of factors, including water temperature, pH. disinfectant contact time,
degree of mixing,  presence of interfering  substances (which may be related to
turbidity), and concentration of available chlorine.  In  order to account for these
data  a regression  model that  explicitly  incorporates the  variables  of
concentration, pH and temperature was developed.  This model is as follows:

             t  =          RC*pHbtempc           (2)

             t  = time to a given level of inactivation in minutes
             C =  concentration of disinfectant in mg/L
             pH = pH at which experiment was conducted
             temp = temperature at which experiment was conducted in C

    To provide the Ct. value equation (2) was multiplied by C yielding the
following "Ct" equation:
             Ct = RC

    For the original Ct calculations Equation (3) was applied to animal
mfectivity experiments conducted by Dr. Charles Hibler.
    These  experiments  provided Ct values at 99.99'o mactivatron.  The
equation derived was as follows:
             Ct = 0.985C176 PH2752  temp-'"7     (4)
Equation (4)  was used  as the basis  for calculating Ct values in the SWTR.
The weakness  of this approach is that the calculated Cts are for one level of
inactivation  (99.99%).   Therefore first  order kinetics were assumed to
extrapolate to lower levels of inactivation.  In order to  provide conservative
estimates for Ct values a  1  log safety  factor was used.   That  is. it  was
assumed for  purposes of the SWTR that 99.99% inactivation Ct values  would
be  used as the 99.9%  inactivation Ct  levels.   A more  desireable approach
would  be  to  use actual data to calculate  Ct values  at  lower  levels of
     Therefore, an attempt was made to  find other data sets that would be
consistent  with the  Hibler data  but  would provide  data  at  lower  levels of
inactivation.   Statistical  tests  were  utilized to determine that  a data  set
developed  by Jarroll was consistent with the Hibler data.  A new equation  was
developed  based on the Hibler- Jarroll data as follows:

             Ct = 0.12 I -027 C '9 pH25->6temp-015(5)

where        R. C, pH. ternp, a,b,& c are previously  defined, and
             I  = (nactivation ratio (I0'lt; I0 = initial number of organisms and
             I, = organisms remaining at time t)

These equations based on Hibler  data alone and the equation based on Hibler-
Jarroll data were  shown  to  be compatible at the  99.99% inactivation level
(Table 1).  But as shown in Table 1 the  95% confidence values for Cts at
99.9% inactivation using the  Hibler-Jarroll data are  lower  than the 99.9<>
(actually 99.99%) inactivation levels using the original Hibler data.
     This is an abstract of a proposed presentation and  does not necessarily
reflect EPA policy.

Table 1. Comparison of Hibler Versus Hibler/Jarroll Estimates (at 5*C)

                Hsber             Hibler/Jarroll at 99.9%
at 99.99M>
(Mean Ct)
Distribution Systems:  Treated  Water  Quality  versus  Conform Non-
Compllance Problems.  DONALD J. REASONER (Research Microbiologist,
Drinking Water  Research Division, Risk  Reduction Engineering Laboratory.
USEPA, Cincin-nati. Ohio)  and EDWIN  E. GELDREICH (Senior Research
Microbiologist. Drinking Water Research Division. Risk Reduction  Engineering
Laboratory. USEPA, Cincinnati. Ohio).
    The overall quality of treated drinking water is subject to deterioration
during distribution.  Factors that effect the rate and degree of deterioration
include source  water  characteristics  and quality,  type of treatment  and
treatment effectiveness,  disinfectant  residual,  temperature. pH, flow  rate.
residence time,  organic  carbon available  for microbial  growth, the numbers
and types of microorganisms present, and  distribution system  age  and
condition.   The  bacterial  load  of  the  distribution water  is  significantly
influenced by several of these (actors.
    The occurrence of  coliform bacteria, used as indicators of treatment
effectiveness and sanitary quality, in treated  distribution water is cause for
concern because of the  possibility that disease causing organisms may  also
be present.   Coiiform occurrences  may cause the  utility to be  out-of-
compliance  with the coliform  MCL of the  Primary Drinking Water Standards.
Thus,  conditions that  favor  coliform  persistence or growth within  a distri-
bution system impact  our ability to discriminate between those  situations in
which  there really is adverse  health risk and those in which  there is only an
apparent adverse health risk.
    During the past few  years, documentation  of intermittent and^or persistent
coliform occurrence problems in a  number  of water  distribution systems,
primarily in  the Eastern half of the United States, has stimulated  interest and

concern about  this problem.   This information  suggests  that  there  are
conditions under which coliform survive, or may actively grow, m biofilms  that
develop on the pipe surfaces and sediments in the  distribution system.  While
our  knowledge  of  the  specific  conditions  thai  permit  coliform
persistence/colonization m  distribution  systems  is  incomplete,  educated
guesses can be made  that will help m  formulatmgpractical approaches so
remediation and control  of colitorm noncomphance  problems.   Continuing
research into the  underlying  causes of coliform  persistence colonization m
distribution systems is needed so that we will not have to rely on educated
guesses, but operate on firm knowledge.
    Discussed are  microbiological  growth and  biofilm  formation in drinking
water  distribution systems,  provides  real world  examples of  coliform
persistence problems,  and addresses approaches that have been used to
solve coliform noncompliance problems.
    This is an abstract of a presentation and does not necessarily reflect EPA

Predicting  Exposure  to Water Contaminants in Distribution  Systems.
ROBERT  M. CLARK  (Director,  Drinking  Water  Research  Division. Risk
Reduction  Engineering Laboratory,  U.S.  Environmental Protection Agency.
Cincinnati, Ohio 45268).

    The Safe Drinking Water Act (SDWA) of 1974 requires  that the  United
States Environmental Protection Agency establish maximum contaminant level
goals (MCLGs) for each contaminant which may have an  adverse effect on  the
health of persons.  Each goal is required to be set at a level at which no known
or anticipated  adverse effects  on  health  occur, allowing  for an  adequate
margin of safety. Maximum contaminant levels (MCLs) must be set  as near to
MCLGs as feasible.  Although the  SDWA  has  been interpreted  as meaning
that  MCLs  shall be met at  the consumers tap, most regulatory concern has
been focused on water quality as it  leaves the treatment  plant  before entering
the distribution system.  The  SDWA regulations  that  emphasize system
sampling are those that deal with  microbiological contamination  and total
trihalomethanes. However,  interest is growing in acquiring an understanding
of variations in  water  quality  that  are found in drinking water distribution
systems.    Acquiring  such art  understanding and then  predicting  the
propagation and distribution of water networks requires insight into the kinetics
of formation of chemical and biological substances as well as the hydraulics of
mixing and transport.   The Drinking Water  Research Division of EPA has
developed  several  models for predicting exposure to contaminants in drinking
water distribution systems.   These models include a steady  state model; a
sequential  steady  state modei: a contaminant propagation model;  a time  of
travel model; and, a dynamic water quality algorithm.
    These  models were developed within  the context  of  a cooperative
agreement between the North Penn  Water Authority. Lansdale. PA (NPWA)
and  the EPA's Drinking Water  Research  Division   The NPWA serves  14.500

customers in 10 municipalities with an average of 5 million gallons of water per
day (MGD).  Water sources include 1 mgd treated water purchased from the
Keystone Water Company which is a surface source and 4 mgd from 40 wells
operated by NPWA.   There are  distinct chemical characteristics associated
with Keystone water compared with well waters.  Keystone water contains total
trihalomethane (TTHM) at significantly higher  levels then the well water.  Well
water  contains volatile orgamcs and inorganic chemicals.  The TTHMs in the
Keystone water were  assumed  to be at  steady  state and were used as  a
tracer.  A  major  first  step  in the project  was  to  hydraulically model  the
distribution system in a network represented by 528 links and 456 nodes.  The
network hydraulic  model used was the WADISO Model, developed by the U.S
Army  Corps ol Engineers.  It contains provisions for both steady state and
quasidynamic  hydraulic modeling (extended period  simulation).   Hydraulic
information from  selected scenarios was inserted  into  the Water  Supply
Simulation  Model  (WSSM) developed  by EPA's Drinking  Water Research
Division.  WSSM utilizes the SOLVER  algorithm  based on a series  of
simultaneous equations describing water quality at each node to determine the
steady state concentration throughout the network.
    These models were used to  accurately predict historical TTHM levels in
the NPWA system. From this analysis it was  clear  that some points in  the
system could  exhibit wide variations in water quality data and a study was
initiated at 6 locations in the system to  collect  water quality  data over 36
hours   These data were then used  to develop  and validate the remaining
    The sequential steady  state  model provided excellent representation of
water quality variations  in  the system:  The  contaminant propagation model
illustrated that  even  though  two sources are  located  far  apart,  there  are
portions of the system that can receive flow from both sources.  Average travel
time between various sources and demand points was calculated.
    The dynamic water quality  model requires  much more extensive data
input  than the other models as shown in Table 1.

      Table 1.  Information required by the dynamic water quality model

General Information
              t Time Step
General Network Information:
             Node numbers associated with the end of each Link
             Link lengths
             Pipe diameters
             Node number  associated with each source
            * Node number  associated with each tank
             Tank geometry
 initial Conditions:
             Concentration  at each node at the start of simulation
             Volume in tank at  start of simulation

Information Required (or Each Period:
             * Direction and flow m each link
              Velocity m each link (optionally may be calculated based on
              pipe diameter)
              Concentration in source flow
    However, despite these  complexities  the dynamic  model  provided
excellent representation of water quality variations in the system
    It was concluded that the steady state model  can provide  insight into
overall water  quality  variations  and patterns within  a distribution  system.
interpretation  of predictive modeling results  must be  made in  light of an
appreciation of the hydraulics of the system, in particular an understanding of
the flow patterns and directions that create gradients of concentration.  Quality
modeling is based on hydraulic modeling, and is highly sensitive to hydraulic
modeling  assumptions  and  results.   Field  quality  data is important in
developing, verifying and understanding predictive models.  Such quality data
should be  available on  a time interval  sufficient to  reflect daily  changes m
system dynamics.  Having the tools to predict time-of-travel between points
from any source will allow for realistic water quality monitoring strategies and
to predict exposure from contaminants.
    This is an abstract of a proposed presentation and does not  necessarily
reflect EPA policy.

Laboratory Support for Clinical Samples: Bacterial.  JULIE PARSONNET
(Enteric Diseases Branch, Division of Bacterial Diseases. Centers  for Disease
Conlrof. Atlanta. GA).

    In the evaluation of  an outbreak,  isolation  of organisms m  human
specimens is essential in determining an etiologic agent.  If  a new agent is
sought,  the agent must  be found in  case specimens but not in  those of
controls.  The presence of a  known pathogen  in a vehicle  of transmission
provides circumstantial evidence of causation but, with rare exceptions, it is
not sufficient to establish a definitive diagnosis.
    Human specimens  are commonly analyzed using three  techniques:
bacterial culture often in conjunction with tests for epidemiologic markers (e.g..
serotype.  antibiotic sensitivity profile or plasmid profile), pathogenioty  assays
(e.g.,  toxin assays or molecular probes for bacterium-specific genes), and
seroiogic tests of blood specimens for anti-bacterial antibodies. One or all of
these methods may be applied to  specimens from any given outbreak.  New
techniques such  as gene amplification  may  further  expand  diagnostic
    The increasing  armamentarium  of diagnostic  tools  for detection  ot
bacterial pathogens is  likely  to result  in  the  discovery of  new  agents
However,  expense and  technical  requisites  presently  limit  use ol some
techniques to the research setting

Analysis  of Water  Samples for  Bacterial Pathogens. GERARD  N.
STELMA JR. (US Environmental Protection Agency, Cincinnati. OH)

    Bacteria  associated  with  waterborne  illness  commonly fall into two
categories, enteric pathogens of  fecal origin, and  opportunistic pathogens.
which  may  be  indigenous  to  drinking water  distribution  systems.   The
fastidious  nutrient requirements of most pathogens and the high densities of
natural flora  which compete  for nutrients makes the  isolation  of these
organisms from drinking water very difficult. Isolation of the enteric pathogens
is  further  complicated by their low numbers and transient nature in drinking
water.  The  methods used  for isolation and identification  of these organisms
from potable water generally are modifications of those developed for clinical
specimens, with concentration and/or  enrichment steps incorporated into the
procedure.  Frequently, pathogens cannot be  isolated,  and investigators must
rely on the isolation of indicator organisms of fecal origin, which are present in
higher numbers in polluted  waters.   Recommended procedures for the
isolation and identification of specific waterborne pathogens and indicators will
be summarized.
    This is an abstract of a presentation and does not necessarily reflect  EPA

Virological Analysis of Environmental  Water Samples.  CHRISTON  J.
HURST  (Microbiologist,  United  States  Environmental Protection Agency,
Cincinnati. Ohio).

    Human  enteric viruses  can be found in groundwaters  and surface waters
within  the United States  and other  countries.  Such viruses  are capable  of
persisting through the various  stages of  standard  drinking  water  treatment
processes.  The different enteric viruses groups will be briefly described.  A
summary description is  given  of the methods  that are  currently used for
concentrating viruses from  water samples and performing virofogical analysis
on the resulting concentrates.
    This is an abstract of the proposed presentation and does not necessarily
reflect EPA policy.

Analysis of Water  Samples  for Protozoa.  JAN I. SYKORA (Associate
Professor, Graduate School  of  Public Health. University  of Pittsburgh.
Pittsburgh, PA 15261).

    Laboratory  analysis  of environmental  samples for protozoans requires
special techniques dealing with  concentration and isolation of individual
agents.  Concentration techniques  involve various types of  filtration,
centrifugation.  sedimentation and  flotation. Isolation requires cultivation  of
protozoans  on special media or  direct count of protozoan in  concentrated
samples using direct staining or immunofluorescent  techniques.

    Membrane filtration  is used to concentrate relatively  dense populations of
agents such as free living amoebae,  while high volume cartridge filters are
used for  separation of protozoans present in  low concentration (e.g  Giardia.
    Isolation  of free  living  amoebae is  accomplished  by  cultivation on
nonnutnent agar seeded with bacteria.  Giardta and Cryptospondium counts
are performed by direct  microscopic examination of concentrated samples
    Our  research focused on  recovery  of Giardia  in environmental samples
affected  by temperature (water density) and  suspended solids.  A series of
quality control tests  performed  on  a  variety of  environmental samples
indicated that cyst recovery is low  in  samples  contaminated by elevated
concentrations of suspended solids.  In addition, standard sedimentation at low
temperatures affects isolation of the cyst.
    However,  in spite of these and  other deficiencies the current  Giardia
isolation  technique proved to be successful in monitoring this agent and thus
preventing additional waterborne outbreaks in the system  studied.


                Listing of Speakers and Panel Members
Paul S. Berger. PhD.
Office of Drinking Water
U.S. Environmental Protection
401 M Street, S.W.. Room EB55D
Washington, DC  20460
(202) 382-3039

Mr. Stuart P. Castle
Drinking Water Section
New Mexico Environmental
 Improvement Division
P.O. Box 968
Santa Fe,  NM  87501
(505) 827-2778

Robert M. Clark, PhD.
Drinking Water Research
Water Engineering Research
U.S. Environmental Protection
26 W. Martin Luther King Dr.
Cincinnati, OH 45268

Charlotte A. Cottrill, PhD.
A.W. Breidenbach Environmental
  Research Center
U.S. Environmental Protection
26 W. Martin Luther King Dr.
Cincinnati, OH 45268
(513) 569-7221

Mr. Gunther F. Craun
Health Effects Research
U.S. Environmental Protection
26 W Martin Luther King Or
Cincinnati. OH 45268
(513) 569-7422
Lawrence R. Foster, M.D.
State Epidemiologist
Oregon Health Division
1400S.W. 5th Avenue
Portland. OR  97201
(503) 229-5792

Dr. Charles W. LeBaron
Medical Epidemiologist, Viral
 Gastroenteritis Unit
Centers for Disease Control
Atlanta, GA 30333
(404) 639-2395

Mr. Joseph L. Glicker
Water Quality Director
Portland Water Bureau
1120S.W. 5th Avenue
Portland, OR  97204
(503) 796-7471

Mr. John J. Higgins
Regional Director
Massachusetts Department of
 Environmental Quality
436 Owight Street
Springfield, MA 01103

John C. Hoff. PhD.
Risk Reduction Engineering
Drinking Water Research
U.S. Environmental Protection
26 W. Martin  Luther King Dr.
Cincinnati, OH 45268

Dr. Christon J. Hurst
Health Effects Research
U.S. Environmental Protection
26 W. Martin Luther King Dr.
Cincinnati, OH 45268
(513) 569-7461
        Dr. Gary L. Logsdon
        Chief, Microbiological
         Treatment Branch
        Drinking Water Research
Division U.S Environmental Protection
        26 W. Martin Luther King Dr.
        4526Cmcmnati. OH
Dennis D. Juranek, D.V.M.
Chief, Epidemiology
Parasitic Diseases Branch, CID
Centers for Disease Control
2600 Clifton Road
Building 23/Chambtee
Atlanta, GA  30333
(404) 488-4435

Mr. Peter C. Karalekas, Jr.
Chief, Water Supply Section
U.S. Environmental Protection
Region 1
John F. Kennedy Building
Boston. MA  02203
Mr. Richard J. Karlin
Director, Research Management
AWWA Research Foundation
6666 West Quincy Avenue
Denver, CO  80235
(303) 794-7711

Dr. George P. Kent
Assistant Clinical Professor
Department of Medicine
Stanford University School
 of Medicine
25 North 14th Street, #1060
San Jose. CA95112
(408) 977-4507
        Ms. Janet L. McGoldrick
        Deputy Director
        Association of State Drinking
        Water Administrators
        1911 N. Fort Myer Drive
        Arlington, VA 22209
        (703) 524-2428
        Patricia A, Murphy, PhD.
        Toxicology & Microbiology
        Health Effects Research
        U.S. Environmental Protection
        26 W. Martin Luther King Dr.
        Cincinnati, OH  45268

        Julie Pa;sonnet, M.D.
        Enteric Diseases Branch
        Division of Bacterial Diseases
        Centers for Disease Control
        1600 Clifton Road
        Atlanta. GA  30333
        (404) 639-3753

        Jay R. Poliner, M.D.
        Director. Eastern New York
        Occupational Health Program
        1201  Troy-Schenectady Road
        Latham. NY  12110

Mr. Edwin C. Lippy
109 West Concord Drive
Lebanon. OH  45036

Donald J. Reasoner. PhD
Drinking Water Research
Risk Reduction Engineering
U.S. Environmental Protection
26 W. Martin Luther King Dr.
Cincinnati, OH 45268
(513) 569-7234

Mr. Stig 6. Regli
Criteria and Standards
Office of Drinking Water
U.S. Environmental Protection
401  M Street. S.W.
Washington. DC 20460
(202) 382-7575

Joan B. Rose. PhD
University of Arizona
PHM Bldg. 90, Room 201
Tucson, AZ 85721
 Frank W. Schaefer, III, PhD
 Parasitology and Immunology
 Environmental Monitoring
  Systems Laboratory
 U.S. Environmental Protection
 26 W. Martin Luther King Dr.
 Cincinnati. OH  45268
Gerard N. Stelma. PhD
U.S. Environmental Protectton
Environmental Monitoring
 Support Lab.
Division of Microbiology
Bacteriology Branch
26 W. Martin Luther King Dr.
Cincinnati, OH 45268

Jan L. Sykora, PhD
Associate Professor
Graduate School of Public
University of Pittsburgh
Pittsburgh. PA 15261

Robert V. Tauxe, M.D.
Chief. Epidemiology Section
Division of Bacterial Diseases
Centers for Disease Control
1600 Clifton Road
Atlanta, GA 30333
(404) 639-3753

Neal D. Traven, PhD
Department of Epidemiology
Graduate School of Public
University of Pittsburgh
A436 Crabtree Hall
Pittsburgh, PA 15261

Mr. Jay Vasconcelos
Regional Microbiologist
U.S. Environmental Protectton
Region 10, ESD, Manchester
 Environmental Laboratory
P.O. Box 549
Manchester, WA 98353

Mr. Gayle J. Smith
Bureau of Drinking Water.
Utah Department of Health
P.O. Box 16690
Salt Lake City.  UT  84116-0690
Richard L. Vogt, M.D.
Council of State and
 Territorial Epidemiologists
Vermont Department of Health
P.O. Box 70
Burlington, VT 05401
(802) 863-7240
                           List of Attendees
Ms. Alicia Aalto
U.S. Environmental Protection
Region 8 (8WMDW)
999 18th Street
Denver, CO 80202-2405

Ms. Melanie Abell
U.S. Environmental Protection
Region 8 (8WMDW)
999 18th Street
Denver, CO 80202-2405

Mr. Keith Allen
Mississippi State Department
 of Health
Division of Water Supply
P.O. Box 1700
Jackson, MS 39215-1700
<60t) 960-7518

Mr. Marc R. Alston
U.S. Environmental Protection
Region 8 (8WMOW)
999 18th Street
Denver, CO 80202-2405

Mr. Dennis J. Ait
Iowa Department of Natural
8900 East Grand Street
 Des Momes. IA 50319
Dr. John S. Andrews
Centers for Disease Control
Maiistop F28
1600 Clifton Road
Atlanta, GA 30333
(404) 488-4682

Mr. Thomas E. Arizumi
Drinking Water Program
Hawaii Department of Health
645 Halekauwila Street
1 st Floor
Honolulu, HI 96813
(808) 548-2235

Mr. Anthony E. Bennett
Texas Department of Health
1100 West 49th Street
Austin, TX 78756

Dr. Robert W. Benson
U.S. Environmental Protection
Region 8 (8WMDW)
999 18th Street
Denver. CO 80202-2405

Mr. Dennis A. Berry
Arkansas Department of Health
4815 West Markham
Little Rock. AR 72205

Mr. Chel E  Anderson
State of California Department
 o! Health Services
1836 S. Commercenter Circle
San Bernadmo. CA 92048

Dr Gus Birkhead
New York State Department
 of Health
Tower Building. Room 651
Empire State Plaza
Albany, NY 12237
Mr. Glenn A. Bodnar
Colorado Department of Health
Drinking Water Program
4210 E.  1 Hh Avenue. Room 300
Denver.  CO 80220

Ms Pamela A Bonrud
South Dakota Department
 of Health
523 East Capitol
Pierre. SD 57501
(605) 773-3364

Mr. David J. Borgeson
Hawaii Department of Health
Hazardous Evaluation and
 Emergency Response  Program
P.O. Box 3378
Honolulu. HI 96801-9984
(808) 548-2235

Mt. Kenneth H. Bousfield
Utah Bureau of Drinking Water
P.O Box 16690
Salt Lake City, UT 84116-0690
Mr. Jerry C. Biberstme
Colorado Department of Health
4210 E. 11th Avenue
Denver. CO 80220
(303). 331-4546
Mr. Michael E. Burke
New York State Department
 of Health
2 University Plaza, Room 406
Albany. NY 12203
Dr. Ronald L Cada
Colorado Department of Health
4210 E. 11th Avenue
Denver, CO 80220

Dr. Robert A. Calder
Florida Department of Health
 and Rehabilitative Services
1317 Wmewood Boulevard
Building 5. Room 455
Tallahassee. FL 32399-0700
(904) 488-2905

Mr.  Kenneth C. Choquette
Iowa Department of Public
Division of Disease Prevention
Lucas State Office Building
Des Moines. IA 50319

Dr. Virginia M. Dato
New Jersey State Department
 of Health
Division of Epidemiology
Quaker Bridge Office
Trenton. NJ 0826-0360

Mr. Stuart F. Bruny
Ohio Environmental Protection
Division of Public Drinking
P.O. Box 1049
1800 Watermark Drive
Columbus. OH 43266-0149

Dr. Debra L. Brus
Nevada State Health Division
505 E. King Street. Room 201
Carson City. NV 89710
(702) 885-4740

Dr. Denny H. Donnell, Jr.
Missouri Department of Health
Section of Disease Prevention
1730 East Elm Street
Jefferson City. MO 65101

Dr. Millicent Eidson
New Mexico Department of
 Health and Environment
Office of Epidemiology
Santa Fe. NM 87503
(505) 827-0006

Mr. Gary L. Englund
Minnesota Department of Health
P.O. Box 9441
Minneapolis, MN 55440
(612) 623-5227
Mr. Jeffrey A. Fontaine
Nevada State Division
 o! Health
505 East King Street, Room 103
Carson City, NV 89710
(702) 885-4750
Mr  William H Davis
U.S. Environmental Protection
Region VI
1445 Rose Avenue
Dallas. TX 75202

Ms. Charlene Denys
Alaska Department of
 Environmental Conservation
P.O. Box 0
Juneau, AK 99811
(907) 465-2653

Mr. Barker G. Hamill
New Jersey Department of
 Environmental Protection
Bureau of Safe Drinking Water
Division of Water Resources
401 E. State Street
Trenton, NJ 08625
(609) 984-7945

Dr.  Robert H. Hamm
Indiana State Board of Health
1330 West Michigan Street
P.O. Box 1964
Indianapolis, IN 46206

Mr. Allen R. Hammer
Virginia Department of Health
109 Governor Street, Room 924
Richmond, VA 23219
(804) 786-1766

Mr. Robert Hart
Arkansas Department of Health
4815 West Markham
Little Rock, AR 72205-3867

Mr. Robert M. Gallegos
New  Mexico Environmental
 Improvement Division
Drinking Water Section
1190 St. Francis Drive
Santa Fe. MM 87503
(505) 827-2782

Ms. Judith Gedrose
Montana Department of Health
 and  Environmental Sciences
Cogswell Building
Helena, MT 59620
(406) 444-4740

Dr. Kathleen Gensheimer
Maine Bureau of Health
State House. Station  11
Augusta. ME 04333
(207) 289-3591

Mr Richard B Howell
Delaware Division of  Public
Silver Lake Plaza
P O.  Box 637
Dover. DE 19903
(302) 736-4731
Ms. Vickie D. Hundley
Ohio Department of Health
1372-D West 7th Avenue
Columbus. OH 43212

Mr  Ray Jarema
Connecticut Department of
 Health Services
150 Washington Street
Hartford. CT 06106
Mr. Jim W  Haynes
Tennessee Department of Health
 and Environment
150 9th Avenue. North
Terra Building
Nashville. TN 37219-5404

Mr. Craig W. Hedberg
Minnesota Department of Health
717 SE Delaware Avenue
Minneapolis. MN 55440

Ms. Donna G. Howell
Montana Water Quality Bureau
Cogswell Building. Room A-206
Helena. MT 59620
(406) 444-2406

Mr. Ron Solberg
North Dakota State Department
o! Health and Consolidated
1200 Missouri Avenue
P.O. Box 5520
Bismark. ND 58502-5520

Mr. Kent Kimes
Florida Department of
Environmental Regulation
2600 Blair Stone Road
Tallahassee. FL 32399-2400
(904) 487-1262

Mr. Michael P. Kovach
Michigan Department of Health
3423 North Logan Street
P.O  Box 30195
Lansing. Ml 48909

Ms. Sue Anne Jenkerson
Alaska Department of Health
 and Social Services
3601 C Street. Suite 540
P.O. Box 240249
Anchorage, AK 99524-0249

Dr. Suzanne R. Jenkins
Virginia  Department of Health
Office of Epidemiology
Madison Building, Room 701
109 Governor Street
Richmond, VA23219
(804) 786-6261

Dr. Mark B. Johnson
Wyoming State Department of
 Health and Social Services
479 Hathaway Building
Cheyenne, WY 82002
(307)  777-6004

Mr  Glenn Y. Kataoka
Colorado Department of Health
4210  E. 1tth Avenue
Denver, CO 80220

Ms. Lore E. Lee
Arizona Department of Health
Division of Disease  Prevention
3008  North Third Street
tPhoenix. AZ85012
(602) 392-4002

Mr. Kirk M. Leitheit
Ohio Environmental Protection
Division of Public Drinking
P.O. Box 1049
 1800 Watermark Drive
 Columbus. OH 43266-0149
Ms  Sandra J  Knetzman
New Jersey Department of
 Environmental Protection
Bureau of Safe Drinking Water
Division of Water Resources
P.O. Box CN-029
Trenton. NJ 08625
(609) 292-5550

Mr.  Robert M. Kriil
Vice President, ASDWA and
Wisconsin Department of
 Natural Resources
P.O. Box 7921
Madison, Wl 53713
(608) 267-7651

Ms. Kathy L. Kringiie
Oklahoma State Department
 of Health
1000 Northeast 10th Street
Oklahoma City. OK 73152

Mr.  Donald A. Kuntz
West Virginia Drinking Water
1800 Washington Street, East
Charleston, WV 25305
(304) 348-2981
Mr. Ronald W. McDougal
Maine Department of Human
Division of Health Engineering
157 Capitol Street
State House, Station 10
Augusta, ME 04333
(207) 289-3826

Dr. Louise M. McFarland
Louisiana State Department
 of Health and Hospitals
P O. Box 60630
New Orleans. LA 70160
(504) 568-5005

Mr. Sam W. Lester
Kentucky NREPC
Division of Water
18 Reilly Road
Frankfort Office Park
Frankfort. KY 40601
(502) 564-3410
Mr. Emerson S. Lomaquahu
U.S. Environmental Protection
Region 8 (8WMDW)
999 18th Street
 Denver, CO 80202-2405

Mr. Bernard D. Lucey
New Hampshire Department
 of Environmental Services
P.O. Box 95
Concord. NH 03301
Mr. Frederick A. Marrocco
President. ASDWA and
Pennsylvania Department
 ol Environmental Resources
P.O. Box 2357
Harrisburg, PA  17120

Ms. Barbara Mazur
Missouri Department of
 Natural Resources
 P.O. Box 176
Jeflerson City. MO 65102

Mr. Craig R. Nichols
Utah Department of Health
P.O  Box 16660
Sal! Lake City. UT 84116-0660
(801) 538-6191
Mr. Harry B McGee
Michigan Department of
 Public Health
3500 N. Logan Street
Lansing. Ml 48909
(517) 335-8165

Mr. G. Wade Miller
Executive Director. ASDWA
1911 N. Fort Myer Drive
Arlington. VA 22209
(703) 524-2428

Dr. Michael Moser
Kentucky Department of
 Health Services
275 East Main Street
Frankfort, KY 40621

Mr. Robert L. Munari
Arizona Department of
 Environmental Quality
16405 North 50th Lane
Glendale, AZ 85306
(602) 392-4002

Mr. Al E. Murrey
Idaho Department of Health
 and Welfare
Division of Environmental
Water Quality  Bureau
Statehouse Mail
Boise. ID 83720-9990
(208) 334-5860

Mr. Jay T. Ray
Louisiana Department of
 Health and Hospitals
 P.O. Box 60630
New Orleans. LA  70160

Mr. Barry O'Brien
Maryland Department of the
201 West Preston Street
Baltimore. MD 21201

Mr. Kurt S. Patrizi
Safe Drinking Water Hotline
Geo  Resource Consultants, Inc.
Waterside Mall
401 M Street, S.W.
Washington, DC 20024

Mr. Thomas P. Poleck
U.S. Environmental Protection
230 South Dearborn Street
Chicago, IL 60604

Mr. Frederick W. Pontius
 Regulatory  Agencies Division
American Water Works Assn.
6666 West  Qumcy Avenue
 Denver. CO 80235
(303) 794-7310

 Mr. Joe A. Power
Alabama Department of
 Environmental Management
3200 Uttlejohn Drive
 Montgomery, AL 36109
 (205) 271-7773

 Mr Michael P. Rau
 Colorado Department of Health
 4210 E. 11th Avenue
 Denver, CO 80220
Mr  Richard A Rogers
U-S. Environmental Protection
Drinking Water Section (3WM41)
841 Chestnut Building
Philadelphia. PA 19107

Ms. Shireene Sementi
Idaho Panhandle District
 Health Department
2195 Ironwood Court
Coeur d'Alene, ID 83814
(208) 667-3481

Dr.  Kazim Sheikh
West Virginia Department of
151 11th Avenue
South Charleston, WV 25303
(304) 348-3526

Ms. Pamela J. Shillman
Colorado Department of Health
4210 E. 11th Avenue
Denver, CO 80220

Dr.  Paul R. Silverman
Delaware Division of Public
Bureau of Disease Prevention
P.O. Box 637
Dover, DE 19901
(302) 736-5617

Dr.  James E. Smith, Jr.
U.S. Environmental Protection
26 W. Martin Luther King Drive
Cincinnati. OH 45268

Mr. Mitsuto Sugi
Hawaii Department of Health
Epidemiology Branch
P.O. Box 3378
Honolulu. HI 96801-9984
(808) 548-2235
Ms. Sheila A. Sullivan
U.S. Environmental Protection
Region 5 (5WO-TUB9)
230 South Dearborn Street
Chicago  IL 60504

Ms. Lori V. Talbot
Administrative Assistant
1911 N. Fort Myer Drive
Arlington, VA 22209
(703) 524-2428

Mr. Jeffery P. Taylor
Texas Department of Health
Epidemiology Division
1100 West 49th Street
Austin, TX 78756

Mr. Johnny B. Taylor
Oklahoma StaU  Der    ^nt
 of Health
P.O. Box 53551
1000 Northeast  10th Street
Oklahoma City, OK 73152

Ms. Tina A. Timmerman
North Dakota State Department
 of Health and Consolidated
Division of Disease Control
State Capitol
Bismarck, ND 58505
Mr. Raymond J. Vanisko
New Jersey State Department
 of Health
Consumer Health Services
CN 364
Trenton. NJ 08625
(609) 984-3400
Mr. Arnold J. Viere
Indiana Department of
 Environmental Management
5500 W. Bradbury
Indianapolis. IN 46241

Mr. David F. Waldo
Kansas Division of Environment
Forbes Field
Topeka, KS 66605

Dr. Sanford B. Werner
California Department of
 Health Services
Infectious Disease Branch
2151 Berkeley Way
Berkeley. CA 94704

Mr. Daniel Wilson
Wisconsin Department of
 Natural Resources
P.O. Box 7921
Madison, Wl 53707
(608) 266-7093

Ms. Julia M. Winter
Florida Health Department
1317 Winewood Boulevard
Building 6
Tallahassee. FL 32399-0700
(904) 488-2905

Ms. Narda Tolentino                  Mr  Leigh B  Woodruff
Connecticut Department of             U S. Environmental Protection
 Health Services                       Agency
150 Washington Street                120 Sixth Avenue
Hartford, CT 06106                   Mailstop ES-098
(203) 566-5058                       Seattle. WA 98101
                                    (206) 442-8087
                                    Total Attendance
                                     including Speakers: 128

Uniied Stales
Envtronmental Protection
Center lor Environmental Research
Cincinnati OH 45268
     iiU> K HA1E
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EPA 600-9-90-021