Baltimore
  Integrated Environmental Management Project:

                      Phase I Report
                      Regulatory Integration Division
                     Office of Policy Analysis (PM-220)
                   Office of Policy, Planning, and Evaluation
                    U.S. Environmental Protection Agency
                            May 1987


MD 00355

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                              230R87OO5
               BALTIMORE
INTEGRATED  ENVIRONMENTAL MANAGEMENT PROJECT
              PHASE I REPORT
             Prepared for the

      Baltimore Management Committee
                  • by

              Andrew Manale
              Hope Pillsbury

                  of the

     Regulatory Integration Division
        Office of  Policy Analysis
Office of Policy,  Planning and Evaluation
   U.S. Environmental Protection Agency
         Washington, D.C.  20460
                                May, 1987

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                         ACKNOWLEDGEMENTS


     This  report was prepared by staff of the Regulatory Integra-
 tion Division of the Office of Policy Analysis of the US Environ-
 mental  Protection  Agency.   Credit must go  to  David  Erickson who
 started the  project for  EPA.   Also,  special  credit  and  thanks
 go  to  John Williams who  followed  Mr.  Erickson  as  site director
 until very recently.  He provided considerable energy, creativity,
 and technical knowledge  to advance this integrated environmental
 management study through its first phase.  The authors would like
 to  thank  Robert Currie,  Daniel Beardsley,  Sam  Napolitano,  and
 John Chamberlin  for their  managerial support at EPA.   For their
 substantial technical assistance,  the  authors  also thank Roberta
 Grossman, David  Lee,   Cathy Crane,  Janice  Talsky,  Alan  Jones.
 Special thanks to Dr. Erik Rifkin of  Rifkin and Associates for his
 help in establishing the fabric of  the Baltimore  IEMP and to Randy
 Freed previously  of  Sobotka,   Inc.,  Michael  Alford  and  David
 Sullivan of VERSAR,  Inc., for their help in developing IEMP method-
 ologies
     While we benefitted from the  generous assistance  of  other
 people too numerous to name, we  would especially like  to thank
 the following  individuals   and  organizations  for their  overall-
 direction and development   of  this  study.    In   this  EPA-funded
 study, these groups manage the  Agency's effort to  complete the
 project, a unique  arrangement  for EPA and  local government.   We
 appreciate the strong commitment and effort of:

 Members of the Baltimore IEMP Management Committee

 Mr. J. James Dieter, Assistant  Director, Bureau  of Environmental
     Service, Baltimore County.
 Mr. Claude Vannoy,  Assistant  to the  County Executive  for  Land
     Use, Anne Arundel County.
 Mr. Robert  Perciasepe,   Chief   of  Capital   Improvement  Program,
     Department  of Planning, City of Baltimore.
 Dr. Max  Eisenberg,  Director,  Science  and  Environmental  Health,
     Science and Health  Advisory Group, Office  of  Environmental
     Programs,  State of Maryland, Department of Health and Mental
     Hygiene
Ms. Virginia Kearney (emeritus, represented the City of Baltimore).
Mr. Daniel  Boyd  (emeritus,  represented  Anne  Arundel  County).

Members of the Baltimore IEMP Technical Advisory Committee

Jared L.  Cohon,  Vice  Provost  for  Research,  and  Professor  of
    Geography and Environmental Engineering, Johns Hopkins
    University (Chairman, Technical Advisory Committee)
Frank Hoot, Assistant Commissioner, Environmental Health, Baltimore
      City Health Department (Chairman, Human Health Subcommittee).

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Don Andrew,  Administrator,  Engineering  & Enforcement  Programs,
     Office of Environmental Programs'.
Charles Billings, PhD; Associate  Professor,  Environmental  Health
     Engineering, School  of  Hygiene  and  Public  Health,   Johns
     Hopkins University.
Katherine Parrell,   MD,  MPH;  Chief,   Division  of  Environmental
     Disease Control, Office of Environmental Programs.
David Filbert,  Director,  Division  of  Air  Pollution  Control,
     Baltimore County Department of Health.
Sam Martin, Consultant,  Vice Chairman of TAG, (represented
     Regional Planning Council during Phase I).
Philip Clayton, Manager,  Cooperative Clean Water Program, Regional
     Planning Council.
Paul Keenan, Administrator, Pollution  Control Section,  Baltimore
     City Department of Public Works,  City of Baltimore.
Tom Ervin,  Environmental  Planner,  Anne Arundel County  Office of
     Planning and  Zoning   (Chairman,   Ecological  Subcommittee).
Janice Outen,  Supervisor  of  Water  Quality,  Baltimore  County
     Department of Health.
Bill Wolinski, Water Quality  Coordinator,  Department  of  Public.
     Wo rk s.
Emery Cleaves, Principal Geologist,  Maryland Geological  Survey
     (Chairman, Ground-Water Subcommittee)
N. Singh  Dhillon,  Director,  Environmental  Health,  Anne Arundel
     County Department of Health.
Colin Thacker, Director, Northern Environmental Services,
     Baltimore County Health Department.
John W. Koontz, represented the Enforcement Program, Waste
      Management Program Administration, State of Maryland.


Additional Participants  in  Phase I Baltimore  IEMP
Through their Membership on Workgroups

Joseph Abey
Anne Arundel County  Health  Department

Anthony S. Bonaccorsi
Eastern Stainless Steel Company

Daryl Braithwaite
Clean Water Action Project

Elkins W.  Dahle
Baltimore  City Health Department

Allan B. Heaver
Baltimore  Building Owners and  Managers  Association

Michael K. Hettleman
The Southern Galvanizing  Company

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 Bruce  W.  Jacobs
 General  Physics  Corp.

 Thomas King
 Mueller  Associates

 Jack R.  Lodge
 Baltimore Gas  and Electric

 Genevieve M. Matanoski
 Johns  Hopkins  School of Hygiene and Public Health

 Arthur Nierberding
 Mueller  Associates

 Darryl W.  Palmer
 FMC Corporation

 Velma  Rector
 American  Lung  Association of Maryland

 John Shumaker
 Baltimore  County Department of Health

 Melissa Wieland
 Baltimore  Gas  and Electric

 Susan  S.  G. Wierman
 Office of  Environmental Programs, State of Maryland

 Bruce Windsor
 American  Lung  Association of Maryland

 Joe Macknis
 U.S  EPA  Chesapeake Bay Program

 Rich Batuk
 U.S. EPA Chesapeake Bay Program

Mary Jo Garreis
 Office of Environmental Programs, Maryland

Mary Dolan
 Baltimore City

 David Carroll
 Baltimore City Department of Planning

Stuart May
Dept. of Natural Resources, State of Maryland

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Harold M. Cassell
Dept. of Natural Resources, Maryland

Ajax Eastman
State Water Quality Advisory Council

Daryl Tuckey ,
Bethlehem Steel Corporation

Bill Burgess
Department of Natural Resources,  Maryland

John Hobner
Baltimore County Health Department

Edwin C. Weber
Department of Natural Resources,  Maryland

Neil Thompson
Office of Environmental Programs, Maryland

Tom Kusterer
Office of Environmental Programs, Maryland

Bernard Bigham
Office of Environmental Programs, Maryland

Mark Farfel
Johns Hopkins University

Tad Aburn
Air Management Administration, Maryland

Gregg Mellon
Anne Arundel County

Susan Guyaux
Office of Environmental Programs, Maryland

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                             CONTENTS


                                                         Page


EXECUTIVE SUMMARY                                        ES-1


  i.  'INTRODUCTION

      0 Traditional Approach                              1-1
      0 Integrated Environmental Management               1-3
      0 The Baltimore IEMP                                1-6

 II.  BACKGROUND ON THE BALTIMORE STUDY AREA

        Boundaries                                       II-l
        Climate                                          II-l
        Surface Waters                                   I1-2
        Water Supply                                     II-3
        Air Quality                                      II-3
        Housing       .                                   II-3
        Population Growth and Development                I1-4
        Mortality Statistics                             II-8
        Structure of State and Local Government          I1-8

III.  INSTITUTIONAL STRUCTURE OF THE BALTIMORE IEMP
        AND ITS EVOLUTION

      •° The Institutional Structure                     'III-l
      0 Evolution of the Institutional Structure        III-4
      * Public Education and Involvement                III-7

 IV.  OVERVIEW OF THE PRIORITY-SETTING PROCESS

      0 General Structure of the Priority-Setting        IV-2.
          Process
      " Priority-Setting in Practice                     IV-3
      • Preliminary Defining of the Scope of             IV-4
          Study
      * Selection of Initial List of Phase I             IV-5
          Study Issues
      * Methods for Setting Priorities                   IV-6
      * Ranking of Issues against the Primary            IV-ll
          Criteria

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    V.   ANALYSIS OF HUMAN  HEALTH  RISKS

        0  Risk Assessment  and  its Limitations:                V-l
            An Overview
        0  Organics in the  Ambient Air                         V-7
        0  Metals in the  Ambient Air  and  Lead  in  the           V-14
            General Environment
        0  Indoor Air Pollution                               V-19
        *  Trihalomethanes  in Drinking Water                   V-23
        0  Risk Comparisons                                   V-28
        0  Summary of Results                                 V-30

   VI.   ANALYSIS OF SOURCES WITH  POTENTIAL ADVERSE
        IMPACTS ON GROUND-WATER

        0  Objectives                                         VI-1
        0  Overview of the  Methodology                         VI-2
        0  Background of  Members of  Ground-water               VI-4
            Subcommittee .
        0  Data Collection                                    VI-4
        e  Performing the Scoring  of Ground-Water             VI-8-
            Resource Damage
        0  Results of the Rankings                            VI-10
        0  Limitations of the Analysis                         VI-12
        0  Additional Analysis  of  Metals  in                   VI-15
            Ground-water

  VII.   ANALYSIS OF ECOLOGICAL IMPACT

        0  Defining an Approach to the  Harbor Issues         VII-2
        0  Harbor Overview                                   VI1-3
        0  Defining an Approach to Studying the Harbor       VII-6
        0  Monitoring Results                                VII-7
        0  Determining Methodologies for  Setting             VII-10
            Priorities within  the Harbor
        0  Indexing                                          VII-11
        0  Results of Indexing  Exercise                      VII-13

VIII.  COMPLETION OF THE PRIORITY-SETTING PROCESS

        0  Reducing the Number  of  Issues for Study          VIII-1
        0  Reducing the Number  of  Issues from Ten           VIII-2
            to Six
        0  Applying the Secondary Criteria                  VIII-3
        •  Developing the Phase II Workplans                VIII-5
        0  Special Attention given to Metals in  the         VIII-6
            Environment
        0  Priority Setting Through Budget Allocation       VIII-10

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                                                     Page

IX.   PHASE II WORK PLANS

       Air Toxics                                    IX-1
       Indoor Air                                    IX-3
       Underground Storage Tanks                     IX-4
       Multimedia Metals   .                          IX-5
       Baltimore Harbor                              IX-7

 X.   CONCLUSIONS

     0  Conclusions Regarding Institutional            X-2
         Arrangements
     '  Analytic Findings                              X-2


 APPENDIX A      GENERAL IEMP METHODOLOGY

 APPENDIX B      LIST OF ISSUE PAPERS; SAMPLE
                   ISSUE PAPER

 APPENDIX C      EPILOG

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             EXECUTIVE SUMMARY

                 Baltimore
Integrated Environmental Management Project

               Phase I Report

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      This  report  describes  the  first  phase   of  the  two-phase
 Baltimore  Integrated Environmental Management Project (IEMP) con-
 ducted by  the Regulatory Integration Division of the Environmen-
 tal  Protection  Agency   (EPA).   EPA   initiated  the  project  in
 Baltimore  as  part  of its pursuit of  new  approaches to environmen-
 tal  management and policy.  The purpose  of the IEMP is to identi-
 fy and assess the significance of a selected set of environmental
 issues that  concern management,  to   set  priorities  for  action
 among these issues, and  to assist local  authorities in responding
 to environmental problems they have identified.

      The IEMP approach is based in part  on risk assessment and on
 risk  management.   It  uses  estimates  of  risk  (that  is,  the prob-
 ability of  adverse  effects)  as the common measure  for comparing
 problems and  setting  priorities  among   issues  affecting  human
 health, involving  different  pollutants, sources,  and  exposure
 pathways.  The  risk  assessments are  used in  risk  management,  a
 process in  which  policymakers balance programs to  reduce risks
 against available  resources  to  support  those programs.   In  its
 simplest form, it  requires  an examination of how large the risks
 are,  how  much the  risks can  be  reduced by  various  regulatory
 controls, and  the cost  of  controls.   Also,  the  projects  are
 intended to involve all  responsible local parties and agencies in
 actually managing  and  coordinating  the  projects, ensuring that
 issues of greatest local concern are adequately addressed.

      Projects typically  have  two  phases.   In  the  first  the
 decision-making structure  of  the project  is  established,  key
 environmental issues are identified,  and priorities  for detailed
 study are  set among them.   In the  second  the IEMP  studies  the
 priority issues in greater  depth and  develops  potential  strate-
 gies  for their control or resolution.

 THE BALTIMORE IEMP

 Description of the Baltimore IEMP

     The  Baltimore IEMP is a  cooperative  effort among  EPA  and
 the governments of the State of Maryland, the  City  of Baltimore,
 Baltimore County*  and Anne  Arundel County.   The Baltimore area
 was chosen, in large part,  because EPA and local officials wanted
 to explore better ways to identify,  assess,  and manage the human
health risks of environmental pollutants in the  area.   It repre-
 sents the second  of  five,  full-scale  geographic projects initi-
ated to  date.   Most  important,  the  Baltimore IEMP is different
 from other IEMP projects  in that the  authority for project direc-
tion and policies  and  resource  allocation res.ides with state and
 local officials"!   Though  EPA has set  the overall study objectives
and the level of  resources  for  the  project,  it has  played only
a support and advisory role  in overall project management.  This
                               ES-1

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experiment in  local  participation in, project  management of  the
Baltimore project is intended to achieve greater  local  commitment
and to test a different approach to local environmental management.
Emphasis is on local control rather than federally-directed  quan-
titative analysis of environmental problems.

     The study  area  (described in  Chapter  II) covers  Baltimore
City, which  includes the  Port  of  Baltimore,  and Baltimore  and
Anne Arundel Counties  (see Figure ES-1).  The greater  Baltimore
area is  representative  of  older,  industrialized  cities of  the
East Coast  in transition  from  smokestack  to more  diversified,
service economies.   Its  present  environmental  concerns  derive
largely from the  industrial and  commercial  activities  that  are
ongoing and  of its  past  and  from present-day cars  and trucks.

The Institutional Structure of the IEMP

     The institutional structure (described in  Chapter III) of the
Baltimore IEMP  evolved  in  response to  EPA's  decision to test the
hypothesis that  delegating  management  authority  will  lead  to
active local participation and  commitment to project objectives.
The Management  Committee  (MC)  is the vehicle for State and local
participation and  provides  project  and  policy  direction.   The
Technical Advisory  Committee (TAG),  composed  of  local  and  State
environmental and public health professionals, provides advice to
the MC.   EPA provides  administrative,   technical,  and analytical
support.  In the concluding stage of Phase I, the general involve-
ment in the IEMP widened to nearly 60 people representing  industry,
public interest  groups, government,  and academia.   They serve on
workgroups  established  to  develop and  excute workplans  for Phase
II issues.   For the second phase  of the project,  the Management
Committee has  constituted a  Risk Assessment  Review Panel, con-
sisting of scientists from Johns Hopkins University,  to provide the
MC with  scientific  and technical  advice  on  questions related to
risk assessment.

The  Process  for  Setting Priorities in Phase  I

     The purpose  of Phase  I  was  to identify  issues for further
study  in  Phase II.  The Baltimore IEMP set  priorities  among the
issues on  the  basis of  available information,  supplemented by
data from  a brief ambient air monitoring effort conducted  by the
EPA.   It  was not  a  strictly scientific endeavor,  but rather an
exercise  in policy analysis using scientific  information;  expert
judgment; and  reasonable assumptions,  where  gaps  in  data existed.
Two  sets  of criteria were used: primary decision criteria which
relied heavily upon  scientific  data  and  professional  expertise
and  secondary   criteria  which  drew on  pragmatic  considerations
by local  officials  regarding  the  best use  of  study  resources.
                                ES-2

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        FIGURE ES-1




BALTIMORE I.E.M.P. STUDY AREA
          PENNSYLVANIA

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     The TAG had the responsibility  for developing  both  the  ini-
tial list of environmental issues and,the  priority-setting proc-
edures that would  be  used in  ranking  issues on this  list.   The
MC had the final say in  the  adequacy of the initial list  and in
the selection and  relative funding of  issues  for Phase II  study.

Defining the Scope of the Project

     The scope of  the  project  evolved from  numerous EPA discus-
sions with State  and local  governments.   Toxic pollutants  were
chosen because of  the  general  consensus that  the greatest  analy-
tic contribution could be made in this area.  The same discus-
sions persuaded the Baltimore  IEMP to  include  ecological effects
of both conventional and  other than conventional water  pollutants
and exclude  issues that  could  not  reasonably  be  handled  with
anticipated project  resources^   (e.g., conventional   air  pollu-
tants, occupational exposures,  food chain  exposures).

Selecting the Initial List of Environmental Issues

     The Technical Advisory  Committee drew up a list  of thirty-
two topics (described  in Chapter IV)  for  preliminary  screening,
based on  their  previous   experience  with  pollution problems  and
on professional judgment.  The  issues dealt with risks  to human
health and potential  to   cause  damage  to  ecosystems and natural
resources, such as ground water.   The TAG did not  consider the
thirty-two issues a comprehensive list of  the most  pressing envi-
ronmental problems in  Baltimore.	This  process was neither de-
signed nor ever  intended to identify  systematically every envi-
ronmental problem; no process could do so  given data limitations.

Developing the Method for Setting Priorities in the Initial List
of Issues

     The problem for  the TAG lay in  developing  a  procedure  that
permitted comparing different environmental  problems  (e.g.,   sub-
stances that may  cause  cancers  versus industrial  effluents  that
disrupt ecosystems), yet  could make best use of available scienti-
fic information.

     Rather than  making   this  type  of tradeoff  immediately, the
TAG decided to  rank the issues against three  separate  measures
of risk:  risk  to  human health,  potential  to cause  adverse ecolo-
gical impact,  and  potential  adverse  impacts  to  ground-water.
Each  type  of  risk  required  a  different  method  for  determining
the ranking  of .these  issues  with  regard  to the  measure.   The
problem of comparing different environmental problems  (e.g., human
health vs. ecological  impact)  was  deferred until after  the  eval-
uation of issues within the categories of human health, ecological
                               ES-3

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impact, and  impact  on  ground-water  resources.   As  it  happened,
selection of  issues  for Phase  II study did  not  require  making
these tradeoffs.

     In developing  measurements  of  human  health  risk  for  air
pollutants, the human health  subcommittee  used  quantitative  risk
assessment for  carcinogens.   For  non-cancer health risks,   the
subcommittee used EPA  Reference Doses (RfDs) that  indicate  what
levels of a  pollutant  may  pose  noncancer  risk.   For indoor  air,
the subcommittee  used  best professional  judgment  regarding  the
risks because the only  existing data  were  for  exposure  levels in
other cities.  The work  of the  subcommittee is  further  described
in Chapter V.

     The ground-water  subcommittee developed an index (described
in Chapter VI) to rank the relative importance  of various sources
and classes of pollutants that may damage ground-water resources.
The subcommittee relied  primarily on  their professional  judgment
to assign  scores  to different  potential threats  to ground-water
which in turn were used to  establish their  relative ranking on the
index.  The  index had  two basic  components capturing  different
aspects of the  possible effect  of a  potential source on  ground
water: pollution and economic impact.

     The ecological subcommittee  used indexing as  the  priority-
setting tool for  Phase  I.The process (described  in Chapter  VII)
compares existing pollutant  concentrations in  the  ambient  water
to generally applicable  reference values.

     All three  of the TAC.'s  methods  included   appraisals  of  the
degree of uncertainty  associated  with the  analysis of each prob-
lem.  These  appraisals   were  qualitative  and based on  the  best
judgment of the committee members.

Ranking the Initial Issues against the Primary  Criteria

     For setting priorities among potential health'problems,  the
human health subcommittee defined the primary criterion as aggre-
gate expected increases  in the  incidence of disease.  On the ba-
sis of this  criterion  and  the quality of the available data, the
subcommittee recommended   five  issues to the full  TAG  for study
in Phase  II:  trihalomethanes in  drinking  water;  toxic  volatile
organic compounds  of  low  molecular   weight  organics;  benzene;
metals in air; and indoor air pollution.

     The ecological subcommittee  recommended three issues to the
full TAG based  on the criterion  of  potential  ecological impact:
toxic metals  in ambient water;  previously contaminated sediments
as a source of water contamination; and bioaccumulation of toxics
in aquatic organisms.
                               ES-4

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                                               Figure ES-2
                                  Flow Chart of How the TAC and the Workgroups
                                  Pared down the List of Issues from Ten to Five
                10 Issues
Human Health Risk  Subcommittee
     Benzene
     Tonic Air Pollutio
     Trihalomethanes in
          Drinking  Water
     Metals in Air
     Indoor Air Pollu

Ecological Impact Subcommittee
                                 Combine and
                                 Redefine to
                                 6 Issues
      Air Pollution
Trihalomethanes in
                                Indoor Air Pollution
     Metals-
     Sediments '
     Bioaccumulation
          Toxics in
          Aquatic Organises
                                Metals in the
                                     Environment

                                Harbor
Ground-Water Resource ^Damage Subcommittee
     Metals in Ground'
          Water
     Underground Storage
          Tanks
Underground Storage
    Tanks
                         Apply Secondary
                         Criteria
                                                         Tonic Air Pollution
                        Indoor Air Pollution
                                                         Metals in the
                            Environment
                        Harbor
Underground Storage
    Tanks
                           Redo
                           Primary/Secondary
                           Criteria for Metals
                           Resulting in Final
                           List of Issues	

                           Tonic Air  Pollution
                           Indoor Air Pollution
                          •Lead

                           Harbor
                                                                                   Underground Storage
                                                                                       Tanks
  1\Continued in Phase II for comparison, but not for further study'

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      After evaluating  source  categories against  the criterion of
 potential ground-water impact,  the ground-water  resource subcom-
 mittee recommended two issues to  the  full TAG: pollution of
 ground-water by metals and pollution  from underground storage
 tanks.

      In summary,  the first part of the priority-setting process
 reduced the initial list of thirty-two issues to ten (see Figure
 ES-2). Overlap among the ten  study topics allowed the TAG to con-
 dense these into  six issues.  Benzene and toxic  air pollution
 became one issue,  toxic air pollution.  The three issues relat-
 ing  to metals became multi-media  metals.  The two remaining eco-
 logical problems  became the focus of a study of  the Harbor..  The
 remaining 3 topics  were indoor air pollution, underground storage
 tanks, and trihalomethanes (THMs) in drinking water.

 Ranking Issues  against the Secondary Criteria

      The TAG then completed the priority-setting process through
 the  application of  secondary  criteria.  These included:

       1)   Likelihood of making a  significant contribution to lo-
           cal environmental management through a Phase II study;

       2)   Lack  of duplication with existing analyses or control
           programs;

       3)   Technical and political feasibility if implementing
           controls  for  each issue studied; and

       4)   Feasibility  of performing the analysis within time and
           fiscal constraints.

      Of  the  six topics  the TAG determined that trihalomethanes in
drinking  water did not  meet the first criterion.  The exposures,
risks,  and controls for THMs  are well understood for purposes of
risk  management and, further, are under study by EPA for national
regulations.  Thus THMs were  not included as a Phase II study
topic  (although it remains as a comparison point for the Phase II
risk'estimates).  The other five topics remained for Phase II.
(See  Figure  ES-2)

ANALYTIC  RESULTS

     A summary of the analytic results developed in Phase I is
presented  in  this section.   However,  it is important to under-
stand  the  major assumptions on which the results are based.  This
is particularly true in this  case, as the analysis was used only
to select  issues for further  study—not to support risk manage-
ment decisions or control strategies nor to document a local
problem.
                               ES-5

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Limitations and Caveats of the Analysis

     The reader should "keep in mind that the risk   assessments  do
not directly  examine disease  incidence in the local population.
Quantitative risk assessment  uses models  that are  conceptually
simple.  Ambient monitoring  data  or,  where these do not  exist,
estimated ambient levels  based upon  source emission estimates,
are used in  conjunction with exposure  factors  to estimate human
exposure to each substance under study.  These  estimates of expo-
sure in turn are combined with toxicological estimates of potency
to yield quantitative  estimates  of  individual risk.   These  are
expressed as  the incremental  probability  of  disease  incidence
(not death) that would  conservatively  be  expected to result from
that exposure.   Combined  with data on population densities,  the
information on individual  risk can be extrapolated to yield numer-
ical estimates of disease  incidence in  the population attributable
to exposures to each pollutant.

     The models are  deliberately designed to yield  conservative
estimates  both of individual risk and of aggregate disease inci-
dence to average  ambient values  for the  pollutant in question
over long periods of constant exposure.  Their primary usefulness
is thus  in  setting  priorities and  allocating resources  rather
than in  predicting  absolute  risk.   For each of the pollutants
analyzed, the  methodology is more  likely to overstate risk than
to understate it.  However, they  do  not take into account inter-
mittent peak  levels  of pollutants to  which  an individual  may be
exposed during  his  or  her daily  activities and  which,  through
dilution in  the  ambient air,  are  not well represented by ambient
average daily concentrations.   Where  these are expected to occur
frequently,  the  models may be  of limited  use.   The models also
cannot handle  possible synergistic  or  antagonistic effects  of
simultaneous  exposure  to  more than  one pollutant  and  rely  on
simple additive  assumptions,  consistent  with  EPA  guidelines.

     Consequently, our  analyses cannot provide definitive answers
regarding past  or current  risks.  They allow only  a  rough estima-
tion of health  effects  or  environmental conditions that may occur
in the future for the  issues analyzed.   Where situations that
contribute to  these health  effects or  environmental  conditions
change, these estimates of  risk  will no  longer  apply.  Because
of the many  uncertainties and potential omissions, we cannot  say
whether our  evaluation  of  risks to health and  the  environment are
under- or over-estimated.  For  those chemicals  for which the IEMP
was able to  make quantitative estimates of  risks and for the ex-
posure scenarios presented,  the risks  are more likely to be over-
estimated than  underestimated.   To the  extent that toxic  chemi-
"cals about' which we  currently know  little have  been  left out,
risks may be  underestimated.
                                ES-6

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     Also, the  scope  of the  study  unavoidably excludes numerous
 issues that may be of  environmental  importance. Only a  very small
 number of  pollutants  were  examined  for their health and environ-
 mental effects.   The  IEMP,   for  example,  did  not  estimate risks
 from occupational  exposures or  from the ingestion  of  pesticide
 contamination of  foods.  Furthermore,  the  estimates of  pollutant
 concentrations  in  the  various media were severely limited by the
 lack of actual  monitoring data.  Nor were risks from chance occur-
 rences, such as accidental spills or releases  of toxic  chemicals,
 studied.   Also, we did not  monitor ground-water resources for con-
 tamination or conduct a comprehensive survey of the health of the
 harbor.  Finally,  the  examination  of  hospital records  of chil-
 dren's exposure to lead  in dust  suggests  only that an immediate
 health concern  exists  for  a limited population.  The health con-
 cern cannot be  generalized to the population as a whole.

     Risk  assessment in Phase I was conducted as part of an exer-
 cise in policy  analysis to help local decision-makers set priori-
 ties.  The  goal of our  risk  assessments  is  to  determine which
 issues were suitable for a more detailed examination of risks and
 control options  in Phase  II.   The results which we present are
 not statements  about the incidence  of disease in the  Baltimore
 area.

     The results   of Phase I of the  IEMP must, therefore, not be
 looked upon as  the products of a comprehensive appraisal of envi-
 ronmental  risks in the Baltimore area.  The  value  of  the  IEMP
 methodology is that it allows an evaluation and comparison of the
 risks from chemicals  about  which we  know  something.   Management
 of these risks, based  on  the best  current  information, can pro-
 ceed, while research  continues  on the effects of  chemicals about
 which little is currently known*

 Results of the Analyses

     Before summarizing  the  results  of  our  analysis   of human
 health effects,  we want to  provide  some general guidance to help
 understand them.   We  feel  it is important to  provide  a point of
 reference, a baseline, for  our  numerical estimates of  the health
 effects. Thus,  from Maryland statistics for cancer, we  know there
 were 4285 cancer deaths in  1984  in the study area  (see Chapter II,
 Table II-4).  In 1983,  the American  Cancer Society estimated there
 were 1.92  cancer  cases for every cancer death.   Using  these two
 factors, we derived an estimated baseline incidence of  8227 cases
 for the study area.

 Human health issue;  Organics in the Ambient Air

     The limited air monitoring  conducted  by the  IEMP  and r.eview
 of monitoring conducted by  the Maryland Air Management Administra-
 tion provided estimates of  ambient  levels  for a  small  number of
 noncriteria pollutants.  The IEMP also  conducted limited air dis-
perison modeling to estimate the contribution  of  emissions from
publicly-owned treatment works  (POTWs)  to ambient levels.

                                ES-7

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     Of the organic  compounds evaluated in  the  ambient  air,  the
highest measured concentrations were for benzene, xylene,  toluene,
and ethyl  benzene.   Lead had  the  highest  value for  the metals.
Comparison of levels  of  pollutants at  different  monitoring sites
suggests that the concentrations of  some  organics  and metals can
vary significantly throughout the Baltimore area.

     The highest identifiable cancer risk from organics  is attri-
butable to benzene.  Benzene alone accounted for about two-thirds
of the upper-bound estimate (assuming the EPA standard of 70 years
of exposure)  of roughly  3  excess  cancer  cases  a year  from the
organic air toxics examined.  Table ES-1 summarizes  these  results.^-

     Monitoring data  suggested  that there  may also  be  increased
risk of  noncancer health effects  for  benzene  and  chloroform.

Human health  issue; Metals in the Ambient Air

     For the  metals  examined, health  risks were  much lower than
the organics,  with the  possible   exception  of   chromium.  The
health risk from  exposure to chromium depends on  the species of
chromium in  the  air.   The  techniques  employed  in determining
chromium levels in the  Baltimore  area, however,  do not  allow for
determining the relative concentrations of hexavalent chromium,  a
potent carcinogen, to trivalent  chromium,  a  relatively  weak car-
cinogen.   Under the worst case, and unlikely, assumption that all
detected chromium is hexavalent, the upper-bound estimate  (assuming
the EPA standard of 70 years  of exposure) of cancer risk is  roughly
four excess cancer cases a year.  This roughly  comparable to the
total  risk from the organics described above.  Table ES-2 summari-
zes these  results.

     The upper-bound  estimate (assuming  the EPA  standard of  70
years  of exposure)  of cancer  risks  to individuals in areas with
the highest  concentrations of the pollutants  examined  (both  for
metals and for organics)  did not exceed one chance  in ten thousand
for any  pollutant, except  where  one  assumes  that  all detected
chromium was  hexavalent.  In that case, the upper-bound estimate
 (assuming  the EPA  standard  of  70 years of  exposure)  risk would  be
four chances  out  of ten  thousand.
 1  Potentencyestimates  used were  from  EPA's  Cancer  Assessment
   Group (CAG).   They have  received  extensive  peer  review.   The
   exception is  1,2-Dichlbropropane.   For this compound, toxicolo-
   gical staff of  the Regulatory Integration developed the potency
   score using  CAG  methodology.   Review  of  this  score has  been
   more limited.
                                ES-8

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                         Table ES-1

      BALTIMORE  IEMP PRELIMINARY  RISK SCREENING RESULTS

   UPPER-BOUND ESTIMATES Of ANNUAL EXCESS CANCER INCIDENCE:
                 ORGANICS IN  THE AMBIENT AIR

       PHASE  I RESULTS  INTENDED FOR DEVELOPMENT OF THE
                  PHASE II RESEARCH AGENDA
                                 Upper-Bound Annual Cases1,2

        Pollutant                   1985          Revised
   (weight of evidence)3          Analysis4        19865

 Benzene (A)                         1.6             1.8
 Trichloroethylene (B2)              0.1             0.02
 Perchloroethylene (82)              0.2             0.1
 1,2-Dichloroethane (82)             0.04            0.1
 Chloroform (82)                     0.2             0.4
 Carbon Tetrachloride (82)           0.3             0.3
 1,2-Oichloropropane (C)             0.1             0.1

   Total                             2.5             2.8
:THE UNIT RISK FACTORS USED IN THIS ANALYSIS ARE BASED ON
 CONSERVATIVE ASSUMPTIONS THAT GENERALLY PRODUCE UPPER-BOUND
 ESTIMATES.  BECAUSE OF LIMITATIONS IN DATA AND METHODS IN
 SEVERAL AREAS OF THE ANALYSIS, SUCH AS EXPOSURE CALCULA-
 TIONS AND POLLUTANT SELECTION, RISK ESTIMATES WERE CALCU-
 LATED AS AIDS TO POLICY DEVELOPMENT, NOT AS PREDICTIONS OF
 ACTUAL CANCER RISKS IN BALTIMORE.  ACTUAL RISKS MAY BE SIG-
 NIFICANTLY LOWER; IN FACT, THEY COULD BE ZERO.  THE PROPER
 FUNCTION OF THE ESTIMATES IS TO HELP LOCAL OFFICIALS SELECT
 AND EVALUATE ISSUES AND SET PRIORITIES FOR THE TOPICS
 EXAMINED.
2RID'S ESTIMATE OF THE ACTUAL NUMBER OF CANCER CASES IN THE
 STUDY AREA IN 1984 IS 8,000 CASES.  (SEE II-8 AND 9.)  THIS
 NUMBER SHOULD SERVE ONLY AS A POINT OF REFERENCE IN UNDER-
 STANDING THE RISK ESTIMATES PROVIDED.  IN ADDITION, THE -
 RISK ESTIMATES SHOULD NOT BE INTERPRETED AS REPRESENTING
 THE TOTAL UPPER-BOUND CANCER RISKS FROM ALL POLLUTANTS IN
 ANY PARTICULAR MEDIUM.  THEY DO NOT TAKE INTO ACCOUNT ALL
 POLLUTANTS THAT MAY BE PRESENT IN THE MEDIUM, ALL SOURCES
 OF THESE POLLUTANTS, AND ALL EXPOSURE SCENARIOS INVOLVING
 PATHWAYS OR EXPOSURES OF SHORT DURATION TO RELATIVELY HIGH
 DOSES.
3EPA weight-of-evidence classifications:  A = human carcino-
 gen; B2 = probable carcinogen; C = possible carcinogen.
 (See Appendix A for more detail.)
*The incidence estimates listed in this column were calcu-
 lated using cancer- unit risk values developed in 1985.
^The incidence estimates listed in this column were calcu-
. lated using current (5/86) cancer unit risk values.

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                      Table ES-2

              BALTIMORE IEMP PRELIMINARY
                RISK SCREENING RESULTS

            UPPER-BOUND ESTIMATES OF ANNUAL
                EXCESS CANCER INCIDENCE:
               METALS IN THE AMBIENT AIR

    PHASE I RESULTS INTENDED FOR DEVELOPMENT OF THE
               PHASE II RESEARCH AGENDA
                          Upper-Bound Annual Cases*,

     Pollutant               1985        Revised
(weight of evidence)3      Analysis^      19865
Chromium (A)
—Total hexavalent           4.2           4.2
—50% hexavalent             2.1           2.1
—105 hexavalent             0.4           0.4
—1% hexavalent              0.04          0.04
—OK hexavalent              0.00          0.00
Cadmium6 (Bl)           0.00 to 0.05   0.00 to 0.04
 Total                  0.00 to 4.25   0.00 to 4.24
*THE UNIT RISK FACTORS USED  IN THIS ANALYSIS ARE BASED
 ON CONSERVATIVE ASSUMPTIONS THAT GENERALLY PRODUCE
 UPPER-BOUND ESTIMATES.  BECAUSE OF LIMITATIONS  IN DATA
 AND METHODS IN SEVERAL AREAS OF THE ANALYSIS, SUCH AS
 EXPOSURE CALCULATIONS AND POLLUTANT SELECTION,  RISK
 ESTIMATES WERE CALCULATED AS AIDS TO POLICY DEVELOP-
 MENT, NOT AS PREDICTIONS OF ACTUAL CANCER RISKS  IN
 BALTIMORE.  ACTUAL  RISKS MAY BE SIGNIFICANTLY LOWER;
 IN FACT, THEY COULD BE ZERO.  THE PROPER FUNCTION OF
 THE ESTIMATES IS  TO HELP LOCAL OFFICIALS SELECT  AND
 EVALUATE ISSUES AND SET PRIORITIES FOR THE TOPICS
 EXAMINED.
2RID'S ESTIMATE OF THE ACTUAL NUMBER OF CANCER CASES
 IN THE STUDY AREA IN 1984  IS 8,000 CASES.  (SEE  II-8
 AND 9.)  THIS NUMBER SHOULD SERVE ONLY AS A POINT OF
 REFERENCE  IN UNDERSTANDING  THE RISK ESTIMATES
 PROVIDED.   IN ADDITION, THE RISK ESTIMATES SHOULD
 NOT BE INTERPRETED  AS REPRESENTING THE TOTAL UPPER-
 BOUND CANCER RISKS  FROM ALL POLLUTANTS IN ANY PARTICU-
 LAR MEDIUM.  THEY DO NOT  TAKE  INTO ACCOUNT ALL  POLLU-
 TANTS THAT MAY BE PRESENT  IN THE MEDIUM, ALL SOURCES
 OF THESE POLLUTANTS, AND  ALL EXPOSURE SCENARIOS
 INVOLVING  PATHWAYS  OR EXPOSURES OF SHORT DURATION  TO
 RELATIVELY  HIGH DOSES.
'EPA weight-of-evidence  clasaificationa:  A  = human
 carcinogen; 81 =  probable  carcinogen.  (See Appendix  A
 for more detail.)
*The  incidence estimates  listed in  this column  Mere
 calculated using  cancer  unit  risk  factors  available in
 1985.
'The  incidence estimates  listed in  this  column  were
 calculated using  current  (5/86)  unit risk  factors.
^Measured cadmium  concentrations  were below detection
 limits.  For  screening  purposes  only,  we calculated
 risks to human health  assuming a range  in  ambient
 concentration  from  zero  to the detection.limit.

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 Human health  issue;  Trihalomethanes in drinking water

     The  subcommittee  examined  the health risks from ingestion of
 trihalomethanes  (particularly chloroform) in the water from public
 drinking  water treatment plants.

     The  upper-bound estimate (assuming the EPA standard of 70
 years of  exposure) of  cancer risk to individuals is 5 chances in
 100,00  for  either plant  (using  the 1985 unit risk factor  for
 chloroform).  The chloroform levels correspond to an upper-bound
 estimate  (assuming the EPA standard of 70 years of exposure) of
 less than one annual excess cancer case from ingest-ion for each
 plant (using  1985 cancer potency data).  No other monitored
 pollutants  of carcinogenic concern were detected.  Table ES-3
 summarizes  these results.

     None of  the pollutants examined in drinking water appear to
 pose noncancer health  effects at the concentrations found, with
 the possible  exception of lead.   As mentioned earlier with re-
 gard to lead  in the ambient air, total exposure from all path-
 ways is essential in estimating the health risks posed by this
 substance.  Though lead in the public water supply is present at
 very low  concentrations and meets the current standard for drink*-
 ing water quality, it  can, nevertheless, leach out of plumbing
 from residences and the distribution system and hence be present
 at higher levels in tap water.  The subcommittee could not esti-
 mate the  actual contribution of lead in drinking water at the tap
 to health risks from lead.

 Comparison of risks in ambient air and drinking water

     Using the above analyses of the upper-bound estimates (assum-
 ing the EPA standard of 70 years of exposure) of the annual
 excess cancer incidence, we conclude that the magnitude of the
 risks from the examined organics and metals in the ambient air
 and from  THMs in drinking water is roughly comparable—an upper-
bound estimate of 3 excess cancer cases per year..  If all airborne
 chromium  were hexavalent, an unlikely assumption, the upper-bound
 estimate  for the ambient air risk would be roughly twice that of
 THMs—7 excess cases per year versus 3 excess cases per year.
Table ES-4 summarizes these results.

Human health issue;  Lead in the General Environment

     Exposures to lead in the amb'ent air could also contribute
 to the total intake of the metal from all pathways. Low levels of
 lead exposure can lead to hypertension in adult males and blood-
related problems and neurological dysfunctions in children and
 the unborn.   However,  the exposure to the levels of lead in the
ambient air of Baltimore alone are unlikely to lead to these
health problems.
                              ES-9

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                                                  Table ES-3

                               BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS

                           UPPER-BOUND ESTIMATES OF ANNUAL EXCESS CANCER INCIDENCE:
                                    POLLUTANTS IN BALTIMORE DRINKING WATER1,2

                                PHASE I RESULTS INTENDED FOR DEVELOPMENT OF THE
                                           PHASE II RESEARCH AGENDA


                                     Ashburton3                                    Montebello3
                                         Upper-Bound Annual                             Upper-Bound Annual
                                             Cancer Cases                                   Cancer Cases
    Pollutant            Average       	—         Average
   (weight of         Concentration       1985        Revised        Concentration       1985       Revised
    evidence)4           (ug/1)5        Analysis6      19867            (ug/1)5        Analysis6     19867

Chloroform8 (B2)          54.3            0.7          1.6               49.3            0.5          1.1

  Total                                   0.7          1.6                               0.5          1.1
XTHE UNIT RISK FACTORS USED  IN  THIS  ANALYSIS ARE BASED ON CONSERVATIVE ASSUMPTIONS  THAT GENERALLY PRODUCE
 UPPER-BOUND ESTIMATES.   BECAUSE  OF  LIMITATIONS IN DATA AND METHODS  IN SEVERAL  AREAS  OF THE ANALYSIS,  SUCH  AS
 EXPOSURE CALCULATIONS AND POLLUTANT SELECTION, RISK ESTIMATES WERE  CALCULATED  AS AIDS TO  POLICY DEVELOPMENT,
 NOT AS PREDICTIONS OF ACTUAL CANCER RISKS  IN BALTIMORE.  ACTUAL  RISKS MAY  BE SIGNIFICANTLY LOWER;  IN  FACT,
 THEY COULD BE ZERO.  THE PROPER  FUNCTION OF THE ESTIMATES IS TO  HELP LOCAL OFFICIALS SELECT  AND EVALUATE
 ISSUES AND SET PRIORITIES FOR  THE TOPICS EXAMINED.
2RID'S ESTIMATE OF THE ACTUAL NUMBER OF CANCER CASES IN THE STUDY AREA  IN 1984  IS 8,000 CASES.  (SEE  II-8  AND
 9.)  THIS NUMBER SHOULD  SERVE  ONLY  AS A POINT OF REFERENCE IN UNDERSTANDING THE RISK ESTIMATES PROVIDED.   IN
 ADDITION, THE RISK ESTIMATES SHOULD NOT BE INTERPRETED AS REPRESENTING  THE TOTAL UPPER-BOUND CANCER  RISKS  FRC
 ALL POLLUTANTS IN ANY PARTICULAR MEDIUM.   THEY DO NOT TAKE INTO  ACCOUNT ALL POLLUTANTS THAT  MAY BE PRESENT IN
 THE MEDIUM, ALL SOURCES  OF  THESE POLLUTANTS, AND ALL EXPOSURE SCENARIOS INVOLVING  PATHWAYS OR EXPOSURES OF
 SHORT DURATION TO RELATIVELY HIGH DOSES.
'Ashburton serves a population  of 900,000;  Montebello serves a population of 700,000.
*£PA weight-of-evidence classification:  B2 a probable carcinogen.  (See Appendix A for more  detail.)
^Measure of pollutant concentration  in  finished water over 1981-1983, City  of Baltimore Drinking Water Quality
 Data (Versar, 1984).
6Chloroform risk calculation based on the unit risk  factor available in  1985.
7Chloroform risk calculation based on the most current unit risk  factor  (5/7/86).
"Analysis assumes total trihalotnethane  concentration is chloroform.

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                         Table ES-4

      BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS1,2

       COMPARISON OF UPPER-BOUND EXCESS ANNUAL CANCER
      INCIDENCE ACROSS  ISSUES AND POLLUTANTS  IN BALTIMORE

       PHASE I RESULTS INTENDED FOR DEVELOPMENT OF THE
                  PHASE II RESEARCH AGENDA

                       (1986 analysis)

                                                     Drinking
Compound (weight of evidence)3        Air              Water

Volatile Organic
Compounds

Benzene (A)                           1.80
Trichloroethylene (B2)                0.02
Perchloroethylene (B2)                0.10
l,2-Oichloroethane(B2)                0.10
Chloroform (82)                       0.40              2.7
Carbon Tetrachloride (82)             0.30
1,2-Dichloropropane (C)               0.10

                                      2.82              2.7
Chromium (hexavalent)4 (A)         0.00 to 4.2
Cadmium5 (Bl)                      0.00 to 0.04
  Subtotal                         0.00 to 4.24

TOTAL6                              2.8 to 7.1          2.7
     UNIT RISK FACTORS USED IN THIS ANALYSIS ARE BASED ON
 CONSERVATIVE ASSUMPTIONS THAT GENERALLY PRODUCE UPPER-BOUND
 ESTIMATES.  BECAUSE OF LIMITATIONS IN DATA AND METHODS  IN
 SEVERAL AREAS OF THE ANALYSIS, SUCH AS EXPOSURE CALCULATIONS
 AND POLLUTANT SELECTION, RISK ESTIMATES WERE CALCULATED AS
 AIDS TO POLICY DEVELOPMENT, NOT AS PREDICTIONS OF ACTUAL
 CANCER RISKS IN BALTIMORE.  ACTUAL RISKS MAY BE SIGNIFICANTLY
 LOWER; IN FACT, THEY COULD BE ZERO.  THE PROPER FUNCTION OF
 THE ESTIMATES IS TO HELP LOCAL OFFICIALS SELECT AND EVALUATE
 ISSUES AND SET PRIORITIES FOR THE TOPICS EXAMINED.
2RID'S ESTIMATE OF THE ACTUAL NUMBER OF CANCER CASES IN  THE
 STUDY AREA IN 1984 IS 8,000 CASES.  (SEE II-8 AND 9.)   THIS
 NUMBER SHOULD SERVE ONLY AS A POINT OF REFERENCE IN UNDER-
 STANDING THE RISK ESTIMATES PROVIDED.  IN ADDITION, THE RISK
 ESTIMATES SHOULD NOT BE INTERPRETED AS REPRESENTING THE TOTAL
 UPPER-BOUND CANCER RISKS FROM ALL POLLUTANTS IN ANY PARTIC-
 ULAR MEDIUM.  THEY DO NOT TAKE INTO ACCOUNT ALL POLLUTANTS
 THAT MAY BE PRESENT IN THE MEDIUM, ALL SOURCES OF THESE
 POLLUTANTS, AND ALL EXPOSURE SCENARIOS INVOLVING PATHWAYS OR
 EXPOSURES OF SHORT DURATION TO RELATIVELY HIGH DOSES.
'EPA weight-of-evidence classifications:  A = human carcino-
 gen; Bl, 82 = probable carcinogen; C = possible carcinogen.
 (See Appendix A for more detail.)
^Chromium incidence calculations indicate a range of possible
 ambient levels of hexavalent chromium from 0 percent to
 100 percent.
^Cadmium incidence calculations indicate a range of possible
 ambient levels from 0.0 ug/ra3 to detection limits (between
 .001 and .002 ug/m3).
^Numbers have been rounded to one significant decimal.

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     Also, lead in the first few minutes of flow of tap water can
contribute to the Baltimore area residents' overall intake of
lead; it too may put the unborn child and young children at
greater risk of adverse neurological effects and adult males at
greater risk of hypertension.  Finally,  ingestion of lead in
household dust is clearly a very significant threat to the health
of young children in older homes which have been painted with
lead-based paint.

Human health issue;  Indoor air pollution

     The subcommittee reviewed existing studies on indoor pollu-
tion.  The studies, which were not specific to the Baltimore area,
suggested that indoor levels of many pollutants generally associ-
ated with the outdoors may be high enough to warrant public
health concern.  In addition, the indoor environment has its own
pollutants of unique concern, such as radon and tobacco smoke.
Few data were found on actual exposure levels to indoor pollu-
tants in the Baltimore area.

Ground-water resource issue

     The ranking system for determining the relative relationship
of potential threats to ground-water resources was designed to
take advantage of the expertise and professional judgment of sub-
committee members.  This was necessary because of the lack of
data needed for modelling purposes or for validating models that
are or could be developed.

     The ranking system takes into account both pollution  impact
and economic impact.  Pollution impact took into account such fac-
tors as number of sources, release volume, the present and  future
rate of contamination incidents, and the potential extent of
damage.  Economic impact included assessment of the relative mag-
nitude of costs to prevent or reduce contamination, and the cost
of response to contamination, again using best professional  judg-
ment.  Table ES-5 shows the results for the top eight source
types examined by the ground-water subcommittee.

     The two issues that consistently ranked highest as potential
threats were underground storage tanks and multimedia metals
(toxic metals in the various media).  They represent the sources
that are relatively the most important potential threats to
ground-water resources.  The methodology does not  allow us  to
conclude they are problems.  Chapter VI describes  the analysis  in
detail.

Ecological Issue; The Harbor

     The harbor  subcommittee examined   a  number  of different
methods for assessing the  relative significance  of different
pollutants.  For Phase I,  they  used a method,  eco-scoring,  which
compares ambient levels of  toxics in the harbor  and its  tributa-

                                ES-10

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                                  Table ES-5
                                Baltimore IEMP
            Results of Relative Ranking of Sources with Potential
                 Mverse  Impact on Ground-water Resources1'2
Relative Ranking
Based on Equal                     Relative Ranking              # of Times
Weighting of                       Based on Pollution            Workgroup
Pollution Impact and               Impact Weighted as            Members Scored
Economic Impact-*                   Twice Economic^               Top
Underground storage               Underground storage
 tanks                             tanks                              4
Multimedia metals                 Multimedia metals                   3
Benzene                           Benzene                             3
Pesticides/herbicides             Pesticides/herbicides               2
Pollution from farming            Pollution from fanning              1
Landfills                         Landfills                           1
Septic Tanks                      Septic Tanks                        1
Chromium in Harbor                Chromium in Harbor                  1
ifiased on a system developed by the ground-water workgroup, Which ranks
 sources for potential for damage to ground-water resources.  These rankings
 are for the purpose of setting priorities for further study; they do not
 apply to specific sites within the study area, but rather, provide results
 of the workgroups' deliberations regarding the relative ranking of potential
 threats to the ground-water resource.
^Chly the top eight sources are shown; the other five sources can be found in
 Chapter VI.
^The first scoring system used by the ground-water subcommittee weighted pol-
 lution impact and economic impact equally.
^The ground-water subcommittee changed the scoring system slightly, weighting
 pollution impact twice as heavily as economic impact, to determine how sensi-
 tive the scoring system was to variation.
^This counts the number of times the source scored in a ground-water workgroup
 member's top five sources.  As there were 4 members in the workgroup/ the top
 score was 4.

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ries to EPA's Water Quality Criteria.

     For metals in the ambient water,  mercury,  lead,  nickel,  and
copper scored high, though lead was of concern  only in an older
set of data.  Mercury was the metal of greatest concern in the
tributaries.  In the sediments, chromium had a  higher score than
the other metals.  In comparing the metals  in the Harbor with
those in the  Bay, all metals were higher in the Harbor than the
Bay with the exception of copper.   These metals represent the
relatively most important potential threats to  the Harbor.  The
methodology does not allow us to conclude they  are problems.   The
indexing results are summarized in Table ES-6.   Chapter VII de-
scribes the analysis in detail.

CONCLUSIONS ABOUT THE PROJECT TO DATE

     The EPA, Maryland State government, and local government
officials have established the organizational framework at the
State and local level for setting priorities for government
action on environmental issues in the study area.  The Management
Committee MC, with the assistance of the Technical Advisory Com-
mittee (TAG) effectively identified and set priorities among a
wide-ranging and diverse set of environmental issues.

     The Baltimore IEMP has helped State and local governments
develop a working understanding of methods for  analyzing issues.
Priority-setting in the Baltimore IEMP was a hands-on process.
The TAG played an active role through its provision of expert
judgment while it used analytical tools to identify important
environmental issues and compare and rank them  against evaluative
criteria.  The success of representatives of State and local
jurisdictions in reaching consensus on questions of environmental
priorities that unevenly affect them testifies  to the usefulness
of these tools and these governments' ability to use them.  Also,
EPA held workshops for both government officials and the general
public to familiarize them with the use of risk assessment.

     The Baltimore IEMP has helped State and local governments
address a high-priority problem.  The State and counties drasti-
cally reduced the standards for the amount of lead used in solder
and flux in the plumbing of residential drinking water systems
after work during Phase I identified this as a potentially seri-
ous health problem.  However, most of the tangible progress to-
wards solving other environmental problems is generally not ex-
pected until completion of the second phase of  the project.
                              ES-11

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                                         TABLE ES-6
                                       Baltimore IEMP
                  Comparison of Index Values For Harbor Priority-Setting,
                      Using Different Types of Indexing Techniques 1
         Ambient Water Quality
            Harbor
   Ambient Water
Quali ty-Tr ibu taries
Ambient Sediment   Ambient Sediment
Quality-Baltimore  Quali ty-Chesapeake
     Harbor             Bay
Trident
' Data1 .
Zinc °
Nickel +
Mercury • O
Lead +
Copper O
Chromium °
Cadmium °
I HMD
Data2
+
+ N/A
0 O
0
+ 0
+
N/A

+
+
N/A
0
0
O
N/A

N/A
+
N/A
N/A
N/A
+
N/A
 O  Index value greater than 2.
       Criteria)
 +  Index value greater than 1.
 *  Index values less than 1.
N/A Not Available.
(Ambient values are more than twice the level of EPA

(Ambient values are greater than EPA criteria)
(Ambient values are less than EPA criteria) '•
1.  See Figures VII-6 to VII-10 for a presentation of the indexing scores and the
    sources of data used to generate this table.

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     The Baltimore IEMP has provided information that will help
EPA conduct its programs.  EPA has lacked analytical methods  and
procedures for setting priorities among issues that do not direct-
ly relate to health.  In Phase I of the Baltimore IEMP,  we have
made progress in developing  priority-setting tools for ecologi-
cal issues relating to the aquatic environment and a procedure
for achieving consensus on issues of importance to ground-water
resources.

PHASE II STUDIES

     We present below a brief summary of the five issues selected
for Phase II study.  The order of presentation does not reflect
their relative importance.  Importantly, each study area is tai-
lored to Baltimore's needs and with the recognition that local,
state and EPA regional staff are also working in these areas.
In effect, our work fits into the overall area environmental
agenda to maximize what all levels of the governments are learn-
ing about issues in Baltimore.

Air Toxics

     Air toxics were found to be a potentially significant though
undefined threat to public health in the Baltimore area.  The
State air toxics program is being designed to address area-wide
problems from industrial emissions of air toxics.  To complement
this effort, the IEMP air toxics study is designed to address the
so-called "urban soup" where toxic emissions from both point and
area sources combine to form elevated concentrations of pollutants
in localized areas.  The goals are to estimate human health risk
from selected air toxic emissions from both industrial and area
sources and to analyze control strategies to reduce the adverse
health effects.

     An important part of this effort is the Baltimore Total
Exposure Assessment Methodology  (TEAM) study to be conducted in
conjunction with EPA's Office of Research and Development.  This
study will help provide information on the relative risks of in-
door versus outdoor pollution.  The objectives of  the study are:

     - to apply "modified" TEAM methodology to Baltimore to
       estimated exposure of Baltimore area residents of specific
       geographic areas to selected volatile organic  compounds;
     - to compare modeled concentrations with measured ambient
       levels for selected volatile organic compounds.
     - to compare indoor concentrations, outdoor  concentrations,
       and personal exposures.
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 Multimedia  Metals

      The MC and  the  TAG  found  metals from a wide variety of
 sources  and in all media to pose potentially significant health
 and environmental risks.   The  Phase II will focus our limited
 resources on one major issue and allow the IEMP the best chance
 of  assisting local officials in managing it.

      The major task  is to develop cost-effective techniques for
 removal  and abatement of  lead  paint and dust.  An extensive num-
 ber of studies dealing with various aspects of exposure to lead
 indicate that current techniques for abating lead paint and dust
 are not  very effective and, in some cases, actually increase the
 levels of lead dust  in housing.

 Indoor Air  Pollution

      While  data  from other cities suggest that indoor pollution
 may pose significant risk to human health, there is little local
 data on  whether  indoor pollution is also a problem in the Balti-
 more area.

      The goals of the workplan are to learn more about indoor air
 quality  in  Baltimore; to  investigate possible programs to reduce
 exposure from indoor air pollution; and to recommend their imple-
 mentation where  appropriate.

 Underground  Storage Tanks

      The TAG and the MC chose  leaking underground storage tanks
 (USTs) as an issue to be studied in Phase II because USTs were
 highly ranked relative to other potential sources by the ranking
 system used to assess potential damage to ground-water resources.
 Because  Maryland already has regulated underground storage tanks,
 the  UST  workgroup members perceived a unique opportunity to
 develop  a study which would help the state and local government.
 The  analysis focuses on developing an approach to help establish
priorities for inspection and enforcement activities, given the
governments' limited resources.

Baltimore Harbor

     The TAG and the MC chose Baltimore harbor as an issue for
Phase II because of  the importance that pollution of the harbor
can have on the current and future uses of this vital resource.
Our objectives are to define the possible future uses of the har-
bor and to identify  additional research and institutional arrange-
ments that should occur to help environmental decision-makers
understand how to achieve any set of goals they have to ensure
that those uses  can  occur.  The work group will also explore
methods to assess the effects of pollutants on aquatic life.
                              ES-13

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  CHAPTER I




INTRODUCTION

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                    I.  INTRODUCTION
     This report  describes  the  first  phase  of  the  two-phase
 Baltimore Integrated Environmental Management Project (IEMP) ini-
 tiated and  sponsored by  the  Regulatory Integration  Division  of
 the Environmental  Protection  Agency  (EPA).   The purpose  of the
 IEMP is to  identify  and  assess  the  significance  of environmental
 issues of local concern, to set priorities for action among these
 issues, and to analyze appropriate approaches to manage the prob-
 lems we assess.

     EPA initiated the project  in Baltimore as  cart  of its pur-
 suit of  new approaches  to  environmental  management  and policy.
 The project is EPA's second of five larae-scale,  multi-media stu-
 dies on  the effect of toxic  pollutants on human  health and the
 environment in a single geographic area.  Like the other IEM pro-
 jects, the  Baltimore IEMP  differs  from earlier EPA  efforts  to
 control toxics because it  uses  an integrated approach to measure
 the complex, interactive effects of pollutants in the environment
 and to identify  cost-effective  methods  of control  of these air,
 water, and'  soil  pollutants.   The Baltimore IEMP also reflects a
 shift in public  interest  by  focusing  on the  effects  of  toxic
 chemicals, rather  than  "conventional"   pollutants.   Unlike  the
 other TEMPs, the  management  structure  of the Baltimore project
 is unique;  State  and local authorities make the  key management
 decisions and have responsibility and  authority for project direc-
 tion and  policy.  EPA  provides the  financial resource, and EPA
 staff provide technical and administrative support.

     After briefly comparing  the IEM approach  with  traditional
 approaches,  we explain in this introduction the  rationale for the
 integrated approach,  the  objectives  of  the  Baltimore-  IEMP, and
 the contents of this report.

 TRADITIONAL APPROACH

     The United   States  has'  traditionally  responded  to  its
 environmental problems by passing new laws that  focus on aNsingle
 environmental medium, such as  the Clean Air Act,  Clean WateNr Act,
 or Safe Drinking  Water  Act.  Accordingly,  each  major  office  at
 EPA handles  the problems associated with a specific  medium, such
 as air or water pollution and  hazardous waste disposal practices.
 Most state and local  environmental  agencies mirror  this medium-
specific organizational structure.

     EPA has also traditionally focused on one pollutant or class
of pollutants  within each  medium at  a time.   When  applied  to
toxics,  this pollutant-by-pollutant,  single-medium  aoproach has
sometimes led to  environmental programs and regulations characte-
 rized by the inefficient use of resources and ineffective manage-
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ment.  In particular, there has been-concern that the traditional
approach could contribute to a number of unfortunate consequences:

     (1)  The  solution  to  one' single-pollutant,  single-medium
          problem might  simply transfer the  problem to  another
          medium (e.g.,  from  water  to  air),  perhaps  resulting  in
          greater risks and costs of control.

     (2)  Problems,  such as  hazardous  waste,  involving  several
          environmental media  may  not  be  addressed  sufficiently
          by an  environmental  agency   that  generally  examines
          each medium separately.

     (3)  Policy-makers  have  no way of setting priorities across
          pollutants, sources  of pollutants,  and pathways of ex-
          posure in  different  media.  Consequently, environmental
          policies and regulations may not be the most efficient:
          too many  resources may be spent on  some  problems and
          too little on  others.

     (4)  Narrowly  focused  studies  of  pollutants within a parti-
          cular medium  may  not  consider  total  or  cumulative
          environmental  exposure,  either  within the medium  or
          across all media.

     (5)  Laws  and  regulations  developed  by  separate  EPA divi-
          sions or  on  the  basis of  separate analyses may involve
          different  and  sometimes  inconsistent  objectives, meth-
          ods, and  standards.

     (6)  The  single-medium    approach  frustrates  attempts  to
          understand fully  the  relationships  among pollutants,
          media, and control  alternatives.

     Industrial wastewater   treatment,  for   example,  can   shift
pollutants  from  water  to  land or  air.  Though the process pro-
duces a  relatively clean  release to  a nearby  body of water, it
also produces  a  residual sludge containing  many of the  original
pollutants  in  concentrated form to  be disposed  of  on land.  If
not properly  managed,  these  more highly  concentrated pollutants
can leach  from  land disposal  sites into drinking-water supplies,
where they  may  represent  greater  environmental risks  than in
their original  context.   Alternatively,  the  more volatile com-
pounds within  the  sludge  can  evaporate  into  the  air to  create
an air  pollution threat.   Similarly,  air  pollution control  de-
vices, such as  scrubbers,  generate  sludges  that  require  land
disposal which can  also  pose environmental hazards.

     EPA's  traditional   approach  has  also been directed  toward
establishing  policies  and  standards  for the nation.   Though gene-
rally a  reasonable and  effective  strategy,  addressing pollution
on a  national  basis  can  lead to  situations  where  particular


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areas receive  inappropriate  levels of control  relative to their
needs.  Of  special  concern are issues that may be  overlooked or
placed low on EPA's agenda because they have regional, but little
national, significance.

     The risks  from toxic  substances pose  a  more  complex  and
difficult problem for  government  regulation than  the previously
addressed conventional pollutants,  such  as the oxides  of sulfur
in air  or fecal  coliform  in  water.   Even minute  quantities  of
some toxic  substances  can  threaten public health  and biological
systems.  And  sophisticated  monitoring devices can detect these
chemicals at  levels at  which  science cannot,  as  yet,  provide
definitive answers  regarding  their effects on health or ecosys-
tems.  Toxic substances  can  move  through  the  environment in com-
plex patterns, even migrating from one medium to another (by eva-
porating to the air from water or land and leaching from land to
ground or  surface waters).   Our  ability  to monitor  these move-
ments from  the  initial  source  of contamination to the eventual
public exposure or  ecological target  is limited.   We know little
about migration pathways, chemical transformations, and meteoro-
logical and other factors  that affect these; pathways and trans-
formations.  Finally, even should  we  identify pollutants of con-
cern and  their  sources and  pathways  of  exposures, we  may still
lack techniques for their abatement and control.  The consequence
is that we  must  develop  new  strategies for  addressing the prob-
lems created by  the introduction of  toxic  substances  into  the
environment.
                  j,
INTEGRATED ENVIRONMENTAL MANAGEMENT

     EPA adopted the  concept of integrated  environmental
management as a response to  the growing challenge  of toxic pol-
lution and  as  a  potential  solution  to the  shortcomings  of  the
traditional approaches  for  pollution  control.   The  term "inte-
grated environmental management"  covers both  the  evaluation of
public health  and  environmental  risks from  various  pollutants
and the development  of the  appropriate  control strategies  from
a multi-media perspective.   The approach is designed:

     o to account for multi-media phenomena—that is, to identify
       and to  track   situations  where pollution  is transferred
       from one medium  to another;

     o to focus  attention  on the  cost-effective   allocation  of
       resources to program areas  where we see. the largest prob-
       lems; and

     o to address  other  issues that  once lacked  an appropriate
       forum.   An integrated  approach to environmental management
       also calls for a  focus on  a specific  geographic location.
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The geographic basis allows the IEMP to consider  all  major  path-
ways and sources, as well as local meteorology,  hydrology,  indus-
try, population  patterns,  and  social  and  political  factors  in
designing government regulatory strategies.

     The integrated  approach   incorporates  a "systems"  view  of
environmental management—a recognition that media are linked  and
that natural processes and abatement strategies  are interrelated.
The systems approach can have  a profound  effect on environmental
management in a number of ways:  engineers and planners can craft
better strategies by respecting and  exploiting  the linkages,  and
decision-makers can appreciate  better  the  implications  of  their
decisions.

     The IEM projects  are  intended  to  involve all local respons-
ible parties and  agencies  in managing and  coordinating the pro-
jects.  Broad local  involvement  ensures  that issues  of greatest
local concern are adequately  addressed—regardless  of their per-
ceived national  importance.   And,  by  pooling  informational  and
analytical resources  among all levels   of  government  (federal,
state, regional,  and  local),  responsible  agencies  under  the  au-
spices of  EPA are  able to  undertake  efforts  that,  because  of
limited data, manpower, and  funds,  none would  be able to under-
take alone.

     Bringing all  responsible agencies and parties  together  at
the same table has additional benefits.  For example, environmen-
tal problems  can persist  because  the  entity that  discovers  the
problem and  has  the  best   information  regarding  its  nature  is
different from  the  entity  that has both  the  authority  and  the
resources for  solving it.  The  control  agency   may  not respond
because its management priorities are inconsistent with or do not
take into account the  issue at hand.  The remedy  may necessitate
both adopting a  method for making priorities more consistent and
establishing the  organizational link  between  the  two agencies.
The IEM strategy  of  bringing  the  key agents together at the out-
set of the project is  the  first step in the remedy.

     The shift  in  orientation  from  largely  uniform national
policies to a policy that  is peculiar to a  region or  locality, as
embodied in an  IEMP,  also  signals a new  emphasis with regard to
assessing and  managing risks.  These  concepts  are discussed in
Appendix A.  But here  we should note a theme  recurrent  throughout
the project  and  therefore  throughout this  report.   In the first
phase of the  Baltimore IEMP,  we  concentrated on assessing risks
to the environment  and human health to define issues and to rank
them in importance.   The methods  we used  for assessing risk and
environmental impacts  are  intended to help regional  and local
environmental managers make better  environmental  decisions—a key
objective of  the IEMP.  These  decisions,  in turn,  should serve
to focus management efforts in the  second phase of  the  project in
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 the management  of these risks.   Thus,  in terms  of  progress to-
 wards  protection  of environmental resources and human health, the
 real rewards  from the  adoption of these methods are not expected
 until  the  conclusion of Phase  I.

     Finally, the integrated  environmental management  approach
 allows for greater  consistency in  the assessment,  and  greater
 flexibility and   efficiency  in the  management,  of  risk  to the
 environment and human  health.   As noted  above,  laws  and  regula-
 tions  developed  in the  early  stages  of EPA's  efforts  involved
 such diverse  criteria  as  technology  standards,  air  or  water
 quality, health  effects,  and  costs.  To  address human health as
 well as ecological and resource issues  involving different pollu-
 tants ,  sources, and  exposure pathways,  and  to  account for inter-
 media  transfers,  lEMPs  use  the reduction of adverse  effects  on
 human  health,  ecosystems,   or  resources  as  common  measures  of
 effectiveness.  Whenever  feasible,  use  of  such  common  measures
 allow  managers  to compare  different environmental  problems and
 solutions  and  to   set  priorities  for   further  study or  action.
 Comparisons and priorities in  turn make possible the coordination
 of efficient  control  strategies  that  can  achieve  the  greatest
 reduction  of risk at a given cost of control^.

     Though  the  projects are   intended to be "integrative," that
 is, they look at  pollutants and  problems across media, they are
 not comprehensive.Comprehensiveness requires that all potential
 environmental problems be  identified,  evaluated,  and  ranked  in
 importance.  Yet  the sheer  number of potential  environmental and
 toxic  issues exceeds the resources  available to the project.  We
 are limited by  time and  the  size  of  our  budget,  which  is not
 enough to  inventory  all  chemicals  and  their sources or  to fill
 all scientific gaps in knowledge.   Instead,  we must rely heavily
 upon existing chemical inventories and  scientific data that gene-
 rally only  suffice to  characterize  a  limited  subset  of  issues.
 On the  other  hand,  we must  qualitatively  estimate the  social
 "cost" of overlooking important issues because of absence or pau-
 city of data.  Hence, we weigh the adequacy of available data for
 setting management priorities againsj; the expenditure of valuable
 and limited resources in generating new  information.  Furthermore,
 in the step that  we call  "scoping"--that is, defining the scope,
 or comprehensiveness,  of  the  project—and  to  a lesser  extent
 throughout the project, project participants make value judgments
 regardingvthe types of  issues (such as health-related, ecological,
or resource-related) that we will  subject to our screening metho-
dology and  the  amount  of  resources  we  will  devote  to  each.

     At the  completion  of  Phase  II,   EPA's  involvemejnt   in the
 project ends.   Nevertheless,  the  legacy  of  the IEMP  will  be
 improved institutional  structure  and  coherent  management  techni-
ques for making better decisions  on  future  environmental  issues.
The process that has led to  these changes will hopefully continue.
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THE BALTIMORE IEMP

     The  Baltimore  IEMP  is  a   cooperative  effort  with  the
governments of  the  State  of Maryland,  the  City  of  Baltimore,
Baltimore County, and  Anne  Arundel  County.   Since EPA  wishes  to
help local  governments  manage  environmental  problems,   it   is
seeking out  counties and  cities that are likely to  benefit from
the integrative approach.  Baltimore is one of a number of  older
Eastern Seaboard cities with a large number  and variety of indus-
tries traditionally associated with environmental pollution.  EPA
chose Baltimore  because of  the  cooperative  relationships  that
existed between  EPA  and Maryland officials through  such  activi-
ties as the Chesapeake Bay Program, the progressive nature of the
State's and  local  jurisdictions'  environmental  programs,  the
availability of  data on toxics,  and the  presence of high  quality
environmental staff with both monitoring  and  modelling capabili-
ties.  Also  not to be overlooked  was  the  willingness of  local
and State  governments  to  work with  EPA  to  address environmental
issues primarily of local concern.

     The Baltimore   IEMP  represents  EPA's   second  full-scale
geographic project.  Most important, the Baltimore IEMP is diffe-
rent from all other geographic projects in that the authority for
project  direction  and policies  and resource allocation resides
with State and  local officials.  EPA  has  set  the  overall  study
objectives and  the levels of resources for the project.  EPA also
plays a  support  and  advisory  role, leaving  project management
decisions and  control  to local  authorities.   To  our knowledge,
such a  working  relationship with   local  authorities  has  never
been attempted  before by EPA on such a scale.

     Through this  experiment in  local participation  in  project
management of the Baltimore project, EPA hopes to  achieve greater
local commitment to implement EPA's IBM concept. EPA, State, and
local officials  have therefore  focused our  efforts in this first
phase of  the project  primarily  on  making  the process—that is,
how management  decisions are made—work.

     The primary objectives of the  Baltimore IEMP are, in order
of priority:

     o To  establish  the organizational framework  at  the  regional
       and local  levels for identifying environmental issues and
       setting  priorities  for  government  action  oh  them.  The
       project  structure includes decisionmakers at  the appropri-
       ate governmental level of  each  pertinent  agency.

     o To  help  state   and  local  governments develop  a  working
       understanding of EPA's methods  for analyzing issues and
       evaluating control options.
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     o To help State and local governments address high-priority,
       site-specific multi-media and multijurisdictional problems
       through risk  assessment  and management  techniques.   Pro-
       gress toward this goal can  be  measured  in tangible reduc-
       tions in environmental risk.

     o To help EPA set its national agenda and design and conduct
       its programs.   By  understanding   how  Federal  programs
       affect conditions at  the  local level, EPA  is  better able
       to redress  inefficiencies  and  identify  unaddressed  prob-
       lems.  The Regulatory Integration Division, in particular,
       needs to develop  and  improve  methods  for use  in  IEM,  to
       address shortcomings of a non-integrated  approach to pol-
       lution, and  to  test  hypotheses   regarding  policies  for
       environmental management.

     o To provide  the  analytical methods for determining manage-
       ment priorities and to demonstrate their  use  on a limited
       scale.  These methods  may  include  quantitative ri.sk assess-
       ments, cost-effectiveness analysis,  and  other  analytical
       techniques.

     EPA's choice  of the  Baltimore  metropolitan  area  for this
study was not based  on a belief that  the  area  has a significant
toxics problem.   Rather,  EPA  chose  the Baltimore  area because
both EPA  and  local officials  wanted  to  explore better  ways  to
identify, assess,   and  manage the human health  risks  of environ-
mental pollutants  In the area.

WORK PLAN FOR THE BALTIMORE IEMP

     The work  of  the  Baltimore  project  is broken  up  into  two
phases.  In Phase  I,  State, local and  EPA staff  conducted  the
following activities:

     o We  developed  institutional  arrangements  necessary  for
       running and  sustaining  the  project  and  for  determining
       the scope  of  the  project.  ..  We  established  cooperative
       working relationships  with  representatives  of the politi-
       cal jurisdictions in  the  study area.  We also  formed  two
       committees:  the Management  Committee  (MC)  to  make manage-
       ment decisions about  which  problems  should  be addressed
       and the Technical Advisory  Committee (TAG) to  advise  the
       MC and EPA on technical  matters.

     o We conducted  a scoping process where we  identified many
       potential issues for  study  and  established  the criteria
       to be  used  in  the  initial  screening  and  assessment.

     o We conducted an initial  screening and assessment of  issues
       so as to set priorities among them for  further analysis
       in Phase II.
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The products  resulting from  this phase  of  the  project  relate
principally to process; we expected no real  reductions  in health
or environmental risk  during  Phase  I.   In addition to  an effec-
tive institutional  structure,  the  products   are  definitions  of
the environmental issues and work plans for  more  detailed analy-
sis and for development of control  strategies.  These work plans
will be carried out  in Phase  II  of  the IEMP.  Though we  did not
intend to solve  specific  environmental problems  in Phase I,  the
existence of  the  IEMP  and its  committee structures did  spawn
activities that have already  led/to tangible health and environ-
mental benefits.  These are detailed in Appendix C.


Comparison with Other Integrated Environmental Management
Projects

     The  EPA's Regulatory Integration Division  (RID)  has initi-
ated four  other geographic  projects  to  date.   Only the  first
project, conducted  in  Philadelphia is  complete.   The  Baltimore
geographic project has  been conducted  concurrently with a pro-
ject in  the Santa  Clara  Valley  ("Silicon  Valley")  of  northern
California.  A  project in  the  Kanawha  Valley  (West  Virginia)
is drawing  to a close.   In  1986, RID initiated  a new  study in
Denver.

     The Baltimore IEMP differs in two key ways from other lEMPs.
First, as  mentioned above,  it  experiments   with an  innovative
means of managing  an EPA project: management has been delegated
entirely to local authorities, with EPA in a  support and  advisory
role.  Second,  the  initial  scope of the  project  is much broader
than either the Philadelphia  or  the Santa Clara  Valley project.
The unique  management  arrangement explains,  in part,  the broader
scope of the Baltimore project.

     For both the Santa Clara Valley Phase I  and  the Philadelphia
studies, EPA  intended  only  to study human health-related issues.
In the  Santa  Clara Valley,  EPA  and  local  authorities shared
common concerns  about a specific potential public health risk.
The public  had  become  concerned about drinking  water,  following
reports of  contamination  of  the  ground-water from which  drinking
water was drawn.   A similar commonality  of  interests existed in
Philadelphia, the  first large-scale IEMP.   Before the  start of
the IEMP,  Philadelphia had developed ambient air guidelines  for
99 toxic air pollutants*  These guidelines were the result of  the
public's and  Philadelphia health officials'  concern  about  expo-
sures to  toxic  air contaminants.   In particular,   Philadelphia
health officials  were   interested  in determining pollutants  and
sources of  those pollutants that violate  ambient air guidelines.
EPA, on  the other hand,  specifically  wished to  test its methods
for assessing potential human health  risks  from toxic chemicals
released into the local environment.

     In contrast,  the   Baltimore  project  began  with  a  blank
                                        «-.
                               1-8

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managers were  potential  candidates  for  inclusion in the project.
Initially, the  number  of potential  issues  and pollutants  was
extremely large—far  larger  than  the  resources  available for the
project.  Thus,  in  Baltimore we first had to apply  and,  in some
cases,  to develop  the methods  for  narrowing down the  number of
Phase  I  issues from the universe of potential environmental prob-
lems confronting  the  study  area.   [We  describe this  method  in
Chapter  IV.]

     The Baltimore  IEMP does not  attempt to be a comprehensive
qualitative or  quantitative  assessment of all risks from toxic
chemicals in the Baltimore metropolitan area.Tomakesuchan
assessment would have requiredfar more than the resources avail-
able to  the project.   This   report," then,  is   a  review  of  the
methods developed  and  approaches   taken  in  setting  priorities
among  a  limited  number  of  issues  which  included  human  health
risks,  ecological damage,  and resource  protection.   The initial
list of  environmental issues was  developed by local participants
in the  study.

     Adopting an approach  to defining  the  scope of the project
that allowed for a  more  inclusive definition  of study boundaries
and issues  had  far-reaching consequences.   In addition  to  the
issues  studied in  other lEMPs,  such  as  human exposure  to toxics
through drinking  water   and  the  ambient  air,  Phase  I of  this
study also examined indoor air pollution, conventional pollutants
of water,  and  ecological  damage  to  Baltimore  Harbor.   Greater
study breadth demanded a tradeoff, however.  We had  less time and
resources available for  screening*  issues  within any broad cate-
gory of  issues (that  is,  a group of  issues  that can be compared
against a  common  metric) and  for  developing  risk  estimates.

OUTLINE OF  THIS  REPORT

     In the following chapters,  we provide  a brief introduction
to the  Baltimore   study  area  and  how  the  project  is  managed,
describe how we conducted Phase I of the project, and present its
findings and conclusions.

     o  Chapter  II,  "Background  on  the  Baltimore  Study  Area,"
        provides an introduction  to the climate,  the geographic
        boundaries,  the  physical   setting,  the demography,  the
        economy,  the history, and the structure of local govern-
        ment in the Baltimore region.

     o  Chapter III, "The Institutional Structure of the
        Baltimore IEMP and Its  Evolution,"  describes the manage-
        ment of the project and how it came about.
*ln this  context,  screening means making a  rough comparison of
  issued against one or more criteria.


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Chapter IV, "Overview of Priority Setting Process,"
reports on how the  priority-setting procedures were
developed and provides a framework for the following four
chapters.

Chapter V, "Analysis of Human Health Risks," reviews the
screening process for human health risks.

Chapter VI, "Analysis of Sources with Potential Adverse
Impacts on Ground-Water Resources," reviews the screening
process for ranking sources with potential adverse im-
pacts on ground-water resources.

Chapter VII, "Analysis of Ecological Impact," reviews the
screening process for ecological impacts.

Chapter VIII, "Completion of the Priority-Setting Pro-
cess," reports on the issues chosen for each type of im-
pact, the choice of issues based on the primary and then
the secondary criteria, and the results of the priority-
setting process.

Chapter IX, "Phase II Work Plans," presents the work
plans for the issues that are to be pursued in Phase II
of the IEMP.

Chapter X, "Summary and Conclusions," summarizes the con-
clusions the specific findings from Phase I activities,
and the limitations on interpretation of the results.

Appendix A, "General  Methodology," discusses the organi-
zation of IEMP project, the concepts of  risk assessment
and risk management, and the process of  risk assessment.

Appendix B, "Sample Issue Paper," presents an  example
of the kinds of  issue papers that were written to provide
background for and to define the issues  that had been
identified by the TAG.

Appendix C, "Epilogue," describes the activities that the
Baltimore IEMP has spawned and that have led to tangible
health and environmental benefits since  the  start of the
project.
                        1-10

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             CHAPTER II




BACKGROUND ON THE BALTIMORE STUDY AREA

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            II. BACKGROUND ON THE BALTIMORE STUDY AREA
    In  this chapter, we provide a general introduction to the
Baltimore study area.  We describe the climate,  ground and sur-
face waters, the water supply, general air quality,  housing,  the
general history of population growth and industrial  development,
and the economic and population base.  We also present mortality
statistics for the three political jurisdictions.  We conclude
with a description of State and local government institutions
which deal with environmental problems.

BOUNDARIES OF THE STUDY AREA

    The Baltimore  study area covers  Baltimore City, which
includes the Port of Baltimore, and Baltimore and Anne Arundel
Counties.  The primary focus of the first phase of the IEMP,
however, was on a core area consisting of Baltimore  City and the
urbanized, industrialized areas immediately adjacent.  The total
land area representing the core study area amounts to approxi-
mately 300 square miles, lying in east-central Maryland on the
western shore of the Chesapeake Bay, the nation's largest estuary.
Also included are the reservoirs that are sources of drinking
water to the area. Figure II-l shows a map of the general study
area.  Figure II-2 shows the study area in relation to Maryland.

CLIMATE

     The climate of the Baltimore region represents  the intermedi-
ate between the cold of the Northeast and the mild climate of the
South.  The Appalachian Mountains to the. west and the Chesapeake
Bay and Atlantic Ocean to the east also cooperate in creating a
milder climate than that of inland areas of the same latitude.
In the winter, cold weather is moderated by the ocean.  Summers
are warm,  with several periods of hot, humid weather.  The
monthly average temperature in January is 33 degrees F, and in
July, 76 degrees F.  The relative humidity in February, March,
and April is 60 percent and in August, September, and October,
75 percent.

     Annual average precipitation, mostly as rainfall, is about
45 inches and is relatively evenly distributed over the year.
Seasonal weather  patterns are well defined: extended, low-
intensity frontal storms during the winter and spring monthst
and short-duration, high-intensity convective storms during the
summer and early fall.2
                               II-l

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   Figure II-l
BALTIMORE I.E.M.P. STUDY AREA
          PENNSYLVANIA

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            Figure II-2






            BOUNDARIES




              OF THE




BALTIMORE IEMP CORE STUDY AREA

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GROUND-WATER  RESOURCES

     Productive  aquifers  (that  is,   aquifers   that represent  a
potential  source of drinking  water)  underlie much of the coastal
area immediately surrounding  Baltimore  Harbor.3  Because of geo-
logical conditions,  many of these aquifers are vulnerable to con-
tamination, though  they are not currently being used for drinking
water.4  Furthermore,  numerous industrial and  municipal surface
impoundments  and landfills and dumps located within the Baltimore
area are  potential  sources 'of ground-water  contamination.   The
extent of  any damage to ground-water in the Baltimore area is un-
known. ^  Most of  Anne  Arundel  County's and  much of  Baltimore
County's drinking water needs are served by ground-water.

SURFACE WATERS

     The study  area  encompasses  the  Jones  Falls, Back  River,
Middle Run,  Back Run,  Gunpowder  Run,  Bodkin  Creek, and   Gwynn
Falls watersheds;   the  Lower  Patapsco   River;  Baltimore  Harbor
(including, the  Inner  Harbor, Curtis Bay, Northwest  Branch, and
Middle Branch);  and a number  of  small creeks.   All of the water-
sheds fall within the Patapsco River  Basin  and drain  into Chesa-
peake Bay.   The  total  shoreline  included  within the Port  of
Baltimore amounts  to approximately  42  miles,  with 28  miles  in
Baltimore City   and 14  miles  in  Baltimore  and  Anne  Arundel
Counties.

     Streams  within the  area are  generally small,  shallow, and
rapidly flowing.  Each drains an area of a  few square miles into
estuarine embayments.^

     Jones Falls  and its  watershed  (Figure  II-3)  cover some  of
the more  congested  urban  areas  of  the Baltimore Metropolitan
Region.  The  stream originates in Baltimore County; flows towards
the south into Lake Roland, an old, man-made water supply impound-
ment near  the city/county  jurisdictional  boundary;  and  passes
through Baltimore City into a large conveyance tunnel before emp-
tying into Baltimore Harbor.   The  lower urbanized portion of the
watershed is  severely degraded and  representative of the variety
of water  quality   conditions  in  the  region.   Other   important
streams are Herring Run,  which flows through  Baltimore City and
empties into  the Back  River, and  Gwynn Falls, similar in  size,
land use,   and water quality  to  Jones  Falls,  which  drains into
the Middle Branch  of Baltimore Harbor.   Drinking-water impound-
ments include  Druid  and  Lake  Montebello  in  Baltimore  City.
Rivers and reservoirs  not within  the  core  study area are the
Upper Patapsco River, Loch  Raven in  Baltimore County,   Prettyboy
Reservoir in  Baltimore  County,   and  Liberty  Reservoir,  which
straddles Baltimore and Carroll Counties.
                               II-2

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STATE OF MARYLAND
                                    FIGURE  E-3
                         THE BALTIMORE METROPOLITAN AREA
                                      AND
                              JONES FALLS WATERSHED

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WATER SUPPLY

     Water for  residents  of the core Baltimore  study area comes
primarily from  the  City  of Baltimore's municipal  water  system.
The sources for the municipal water supply are:

     a.  the  Gunpowder River,  which  provides water  to  the Loch
         Raven and Prettyboy Reservoirs--the Loch Raven Reservoir
         has a primary water treatment plant;
     b.  the  North  Branch  of the  Patapsco  River,  which provides
         water to Liberty Reservoir,  which  also has  a treatment
         plant; and
     c.  the  Susquehanna  River,  which  serves  as   a  secondary
         source, and  only  for  emergencies   or  special  circum-
         stances.

A small percentage  of total water  consumption  in  the core study
area comes from ground-water,  and only in areas not served by sur-
face water supplies.8

GENERAL AIR QUALITY

     With the   passage  of  State  and   Federal  air  pollution
legislation in  the  late  1960s  and  early  1970s,   the  Baltimore
area has made much  progress in eliminating  the  spot, smoke, and
fly ash that clouded  industrial areas.   Nevertheless, the
Baltimore area   does  not  meet  National  Ambient  Air  Quality
Standards for ozone,  carbon  monoxide,  and  particulate  matter.'
It does meet the other air  quality standards.

HOUSING

     Like most  older,  industrialized cities  of the  East  Coast,
the Baltimore area displays large gradations in the age and qual-
ity of  its  housing stock.   Within  the densely populated urban
core located  primarily in  Baltimore  City,  much-of  the  housing
stock consists  of  brick  rowhouses  built before  World War II.
Many of these units, which had fallen into neglect, are now being
renovated.

     Many of the older  residential structures in  Baltimore City
are suspected of having  been painted  with many layers  of lead-
based paint.  In  addition, most  houses  in  the  study  area have
copper pipes with solder in the plumbing systems.

     With the recent  redevelopment of  the  "Inner  Harbor," there
is renewed interest in downtown living  and  new  housing develop-
ments are cropping up  close to the harbor.   Ringing  the densely
populated areas  of  Baltimore  City  are the  newer  suburban areas
of Baltimore  and  Anne Arundel Counties.   In  these  areas,  the
greater portion  of  the housing stock was built after  World War
II,   primarily since the 1960s.


                               II-3

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POPULATION GROWTH AND INDUSTRIAL DEVELOPMENT

     The natural harbor formed by the 14-mile long estuary of the
Patapsco River where  it meets the waters  of the  Chesapeake Bay
has historically  presented  an ideal  setting for  the  growth  of
commerce.  The waters of  the  harbor  facilitated the transport of
agricultural goods, particularly wheat,  grown in  the  rich soils
of the Western  Shore  and Piedmont.  By  1729, the  land along the
rivers, streams,  and  inlets could claim a population  of almost
1,000 people.  With the uniting  of Jones  and Baltimore Towns in
1743, population  growth accelerated  and led  to the  first signs
of adverse population impact  on  the  environment of the region—a
deterioration of  the  condition of a large marsh  on Jones Falls.

     The end of the 18th century saw Baltimore emerge as the most
important commercial port in  Maryland,  boasting a wide diversity
of industries.  The many rapidly flowing streams invited the con-
struction of  mills.   In  1825,  it became  the  country's   leading
city for the milling  of flour.   The  processing  of .oysters became
an important  industry with  the development of  the steamboat and
the discovery of  the  process  for hermetically sealed metal cans.
By 1870, 10,000 workers were employed in the annual processing of
ten million bushels of  oysters.  The city soon became the  nation-
al leader also in food  processing and canning.

     The construction of the  railroads  in  the early 19th  century
led to  the  development  of  the area  as a  key center  for heavy
industry, particularly  iron and  steel.   First came  iron works,
then locomotive works and steel mills to construct the  iron rails
and steel bridges.   Sparrows  Point  steel  works  began with the
founding in  1887  of  Maryland Steel  Company,  the  progenitor of
Bethlehem Steel Corporation.

     With World War  I  came large  chemical  plants on Curtis Bay.
Shipbuilding, large  copper  smelting  plants, and oil  and sugar
refineries located after the  war  also  along  the  shores of the
lower Patapsco River.

     With the  city's  rapid  growth  in  the  19th  century began
Baltimore's  quest  for an   adequate   supply  of   clean water.
Baltimore formed  the  nation's first public water supply  company
and shifted  its  reliance  on  supplies  from  ground-waters  and
springs to the surface  waters of Jones Falls.  Lake  Roland on the
Jones Falls  was  constructed  in  1861.   Water  from the Gunpowder
River provided the area's first interbasin  transfer to the City
beginning in 1874.

     As in  most densely  inhabited environments,  streams in the
Baltimore area  served a purpose other  than just  as  a source  of
drinking water and as an energy  source;  they were also used  as  a
means for disposing  of waste.   Throughout the  18th century and
                                II-4

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continuing until  today,  industries discharged  their  wastes into
the streams  and  creeks  flowing  to  the  harbor.   Urban  runoff
became a  problem,  as  indoor  plumbing  introduced  in  the  188.0s
emptied into  street gutters.   To  deal with  these  early  water
pollution problems,  in  1911  Baltimore built one  of the nation's
first waste treatment  plants,  Back River Treatment Plant.  There
are now plans  to spend  some  additional $400 million to upgrade
this plant in the next few years.  Baltimore City was also one of
the first major  East Coast  cities to  build separate  sanitary and
storm sewer systems.

     Also during  this  period,  growth  upstream at  the existing
sanitary sewer  systems  caused  massive^  overflows  of  raw wastes
into nearby  streams.  These  incidents  forced  the  State Health
Department to  impose  building  moratoria  on certain watersheds
which, in  some  cases,  lasted  a  decade.  Today,  problems  still
exist such that  septic tanks occasionally  fail  and sewer systems
60 to 70 years old overflow.

     In the decades  immediately  after World War II,  the port has
generally brought prosperity  to the  region.  Stimulus  to growth
of the port has come from many quarters, including grain and coal
export under the United N'ations Relief and Rehabilitation Program
on behalf  of  war-torn nations,  expansion of the  Sparrows  Point
steel plant, and  conversion of  the  Fairfield  building yard into
shipbuilding and  salvage  operations*   Yet  the  port's increasing
reliance on bulk  cargo  serving  large  industries, rather than the
highly profitable general  cargo  business,  hinted  at the larger
Baltimore area's  vulnerability  to  changes  in  the  fortunes  of
these large, generally smokestack industries.

Baltimore Today and Tomorrow

     In the 1980s,  Baltimore remains one  of   the  nation's  most
important commercial and industrial centers.  At .center stage is
Baltimore Harbor, the  Baltimore  area's  most important economic
resource,  and  the commercial and shipping port  it makes possible.
The port itself is estimated to have created some 79,000 jobs and
generates  each year  $300  million in  State  and  local taxes.  And
the port is in  some way  tied' to  one-tenth  of  the value  of all
goods and   services   produced  by  the   State.    Some  4,000  ships
from around the  world  use its  facilities  and  nearly 37 million
tons of cargo,  of which two-thirds is  foreign  cargo, are loaded
and unloaded here.

     In recent years,  urban  renewal has revitalized  portions  of
the harbor,  particularly the  Inner Harbor and  Fells  Point.  The
Inner Harbor is now  one  of  the  region's most desirable locations
for retail and  tourist trade.   Fells Point has  become  a  focal
point for  the  new interest in downtown living.
                               II-5

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     In addition to  commerce  associated  with the port,  manufac-
turing, despite  its   decline  in  relative  importance   to   the
Baltimore area's economy in recent  years,  is  an  important  source
of employment and revenue.  Table   II-1  lists the  area's largest
manufacturing employers.  The  most  important industrial employ-
ers are the  primary  metal  and  electrical/electronics  industries.
Next is  food  processing,  followed  by  the  chemical  industry.


Table II-1; Baltimore Area's  Largest Manufacturing  Employers(1977)
    Employers
Number of
Establish-
  ments
                      Value of
Number of    Payroll  Shipments
Employees  (millions) (millions)
Chemical & Allied
  Products              117
Food & Kindred
  Products              192
Primary Metal
  Industries             44
Electrical/Elec-
  tronic Equipment       92
               9,900

              14,200

              24,000

              24,700
             $150.7

             $178.4

             $457.1

             $424.7
$1 ,192.1

$1 ,567.7

$1,860.2

$1,215.4
Source:U.S.Bureau  of the Census, 1977  Census  of Manufacturing
for Maryland, as  reported  in  Regional  Planning Council, Economic
Indicators; Baltimore Region, 1983 edition.

     The largest  single manufacturing employer in the study area,
Bethlehem Steel Corporation, employs approximately 20,000 people.
Like many  other large manufacturing  employers in  the  Baltimore
area,  it is located within the Port of Baltimore.12

     The Regional  Planning  Council  predicts  that  most new growth
in the  three  jurisdictions will  occur  in the service  and trade
sectors.  In  the  past five  years,  employment in  Baltimore  City
declined by an  estimated 35,000  jobs--half  in manufacturing and
half in government.  As Table II-2 (see next page) shows, antici-
pated  growth in the service sector will  more  than offset contin-
ued declines  in manufacturing.   Service  sector  and trade growth
will also offset  declines  in  the  number of manufacturing jobs in
Baltimore County.  The  greatest employment growth  will occur in
Anne Arundel County, primarily  in the service  sector.

POPULATION TODAY  AND IN THE FUTURE

     After hundreds  of  years   of  sometimes  exponential growth,
population in the two counties  and Baltimore City began  to stabi-
lize in  the   1980s.   Table  II-3  presents  population  statistics
for the Baltimore study area.   The population  of the  three juris-
dictions in  1980  was  1,813,000.   In  1985 it  is  estimated to be
                                II-6

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 Table  II-2:  Changes in  Employment in  the Baltimore  Study  Area
                      Change
                       over
                      1980-851
        % of Total
        Employment
          in 1985
                 Change
                  over
                 1985-901
                    % of  Total
                    Employment
                      in  1990
 Baltimore   Study Area
 10.5
                   31 .5
 Baltimore  City
    Infrastructure
    Manufacturing
    Trade
    Services
    Government

 Baltimore  County
    Infrastructure
    Manufacturing
    Trade
    Services
    Government

 Anne Arundel County
    Infrastructure
    Manufactur ing
    Trade
    Services
    Government
•34,
•  8,
•16,
 -1 ,
 10,
8
6
5
9
4
10,
12,
18,
37,
3
4
9
7
-18.2

 11 .0
  3.2
 -6.9
  6.6
 13.9
 -5.8

 34.3
  2.0
  2.3
  7.2
   .7
 13.1
      20.6
      10.1
      14.2
      26.4
      29.7
      19.7
      12.2
      10.3
      18.8
      18.8
      40.0
 3.0
 1.8
-5.1
-0.4
 7.2
-0.5

11.9
 0.8
-3.5
 4.5
 9.9
 0.2

16.6
 1.3
-0.1
 4.1
 7.9
 3.4
10,
11
18
39
                         10
                         12
                         26
                         31
                         20.4
                         ,0
                         7
                         7
                         4
                         19.1
                         11 .9
                          9.5
                         19.3
                         21 .0
                         38.5
1 Changes  in  the number  of jobs  over the  indicated  period,  in
  thousands, by  place of work.
Source: Regional Planning Council, December 1985,;


1,822,500 and  is projected  to  increase  to  1,838,600 by  1990--
about a  1  percent  increase over  the  decade.   Like most  older,
industrialized cities of  the Eastern  Seaboard,  Baltimore  City's
population, however,   is declining.   It  is projected  to  fall
from 786,800  in 1980  to 749,500  in  1990--an  almost 5  percent
decrease over the decade.   Most  of this decrease will be  offset
by growth in population in Anne Arundel County.

     The population density of Baltimore City is 9,620 people per
square mile—a density almost ten  times greater than  than  of its
surrounding counties.  However,  the  populations of  the  counties
are concentrated around the jurisdictional boundaries shared with
Baltimore City.
                               II-7

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Table II-3: Population Statistics for the  Study Area
Past and Projected Population:
Baltimore City
Baltimore County
Anne Arundel County
Total
T980
786,800
655,400
370,800
1 ,813,000
1985
760,000
665,200
397,300
1 ,822,500
1990
749,500
669,100
420,000
1 ,838,600
Population Density (*85)     Persons per Sq.  Mile
Baltimore City               9,620
Baltimore County             1,094
Anne Arundel County	952
Source:Regional Planning Council, February 1986.

MORTALITY STATISTICS

      Table II-4 (see next page)  shows  total deaths  for  selected
causes in the  two  counties  and  Baltimore City.  The data  in  the
table serve only to give a very rough idea of the relative  impor-
tance of the various  causes  of  death in the  three  jurisdictions.
They are not  necessarily good  indicators  of the  general  health
of the population.

STRUCTURE OF STATE AND LOCAL GOVERNMENT

     In this section of  this  chapter, we describe the institution-
al context  in  which the Baltimore  IEMP  is  taking  place.  Under-
standing the  agencies,  the  formal  relationships among  them  for
making decisions of mutual  interest,  and their legal responsibi-
lities is  crucial  for   developing   effective  and  implementable
recommendations.  Solving environmental  problems requires  coope-
ration among agencies and jurisdictions.

     The existing  structure  of  state and federal environmental
programs is the direct consequence of piecemeal enactment of fed-
eral law.   Over  a number of years, laws were passed  to address
environmental problems  by  the   medium   immediately  affected  by
pollution, such  as  air  pollution or  water pollution.   With each
new federal law  came  the governmental apparatus  to implement  it.
At the federal level,  the result  has been departmentally separate,
medium-specific programs,  such  as  air,  water,  and  hazardous
waste (land and  ground-water )   programs.   States  have generally
adopted analogous  institutional  structures  to  carry out  their
responsibilities under  these federal laws or  to establish state
programs not mandated by federal law.

     Under most federal  laws, the federal government (EPA in this
instance) sets the  rules and the states must  enforce them under
the threat of losing federal  funds.   This entails,  in part, devel-
oping implementation  plans for  how  enforcement of  these rules by
                               II-8

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             TABLE  II-4:  DEATHS BY SELECT CAUSES IN
     BALTIMORE CITY, BALTIMORE COUNTY, AND ANNE ARUNDEL COUNTY
                        Data Are for 1984
          Causes
              Number of Deaths
Diseases of the heart
Cancer^/3
Cerebrovascular disease
Accidents and adverse
 effects
Pneumonia & influenza
Septicaemia
Chronic obstructive
 pulmonary diseases &
 allied conditions
Homicide
Diabetes Mellitus
Congenital anomologics
Total deaths 4
Baltimore
   City

   3,440
   2,248
     603
     287

     262
     215
     215
     204
     178
      39
Baltimore
  County

  2,198
  1,379
    382
    186

    147
     75
    163
     36
    101
     25
Anne Arundel
   County

     827
     658
     139
     113

      52
      38
      92
      20
      62
      12
   9,554
  5,638
   2,474
Source: Maryland Center for Health Statistics, DMH, Maryland Vital
Statistics; Preliminary Report 1984.
 1 Population estimates for 1984 are from the Regional Planning
   Council
 2 Figures represent actual rather than age-adjusted rates.
 3 It is important to realize that there are approximately 2 cases
   of cancer for every cancer death, according to 1983 American
   Cancer Society Data for the nation (actual figure: 1.92 cases
   per cancer death).
 4 Total includes deaths from other causes.

state and local agencies will be carried out.  States and local
agencies do have the option of doing more than what federal law
requires, however.  In the case of toxics, many states (such as
Maryland, California, New York, and New Jersey) have aggressively
developed their own programs.  This is because EPA has issued few
rules and regulations addressing the control of toxic substances
—as opposed to the more "conventional" pollutants.
                                                            i
     In describing the institutional framework for the Baltimore
IEMP, we identify the program medium, such as air or water, and
then describe the responsible state and local entities and their
specific responsibilities.
                               II-9
                                                    Will

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Institutional Framework for Water Problems

     Both State  and  local   governments  carry  out  regulatory
programs relating to water problems.   Local governments also have
responsibility for  issues  not  specifically addressed  in  Federal
or State law.

     State regulatory responsibilities  for water are  divided  up
among agencies according  to whether the  water is  considered  an
environmental resource or  an item of interest  to public  health.

Program distinctions  are  also made  according to the  geological
location of  the  water—i.e.,  whether  it is  ground or  surface
water.

Surface Waters.  The  Office of  Environmental  Programs (OEP)  of
the Maryland  State  Department of  Health  and  Mental  Hygiene  is
responsible  for all clearly health-related issues regarding water
use.  It is  charged with  managing  and  regulating  the  waters  of
the State to protect the beneficial uses of

     o  water contact recreation;
     o  fish, other aquatic life, and wildlife;
     o  shellfish harvesting;
     o  public water supply;
     o  agricultural water supply; and
     o  industrial water supply.

     Though  OEP is  nominally responsible for protecting all sur-
face waters,  these  responsibilities  actually  pertain primarily
to protecting waters  from sources of  the pollution that can be
clearly defined  (point  sources)  and  only to  a subset (agricul-
tural runoff)  of  the  pollution  deriving  from large  numbers  of
small sources distributed  over a large  area (non-point sources).
Point sources fall  under  the purview of  the Federal Clean Water
Act, for which OEP  is given the State enforcement responsibility.
These include issuing NPDES (National  Pollution  Discharge Elimi-
nation System) permits  for point source  effluent discharges and
enforcing technology-based  emission standards.   It  also issues
permits for  land disposal  of wastewaters.

     Publicly owned  water  treatment  works   (POTWs,   or sewage
treatment plants)  are regulated as point sources.   OEP issues
effluent permits  and ensures that  POTWs are in  compliance with
Federal and  State  regulations and the  water-quality  management
plans for individual river  basins.

     The POTWs,  and hence  the local government  operating  them,
are responsible, for implementing sewage pretreatment  ordinances
established  by the  State or EPA  and for monitoring  the  quality of
                              11-10

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 the influent  to  sewer  treatment plants.  They must perform secon-
 dary and  advanced treatment  of  sewage as  required by  State or
 Federal law.   The three POTWs  in the Baltimore  core  study area
 are Patapsco,  located  in Baltimore City;  Back  River,  located in
 Baltimore  County;  and  Cox  Creek,  located in Anne Arundel County.

      Responsibility  for  State  control  of  nonpoint  sources  of
 pollution,  such  as urban (stormwater)  or agricultural  runoff, is
 shared by  the  Water  Resources  Administration  in  the  Maryland
 Department of  Natural  Resources  (DNR) and  OEP.   DNR  establishes
 and enforces  policies  and  regulations   relating to  stormwater
 (especially urban  runoff)  management,  and it approves county and
 municipal  ordinances   and  implementation  plans.    DNR  is  also
 charged with  preventing  oil  pollution by  setting  and enforcing
 standards  and  regulations for  oil  operations  and  for  managing
 watersheds  and  resources.   The  latter entails  flood  management
 and issuing permits  for watershed use, erosion control, dam safe-
 ty,  dredging,  and  water appropriations  and licenses  for mining.
 OEP's share of  responsibility  for  controlling  nonpoint  source
 pollution  lies  in administering  programs,   in  coordination with
 the State  Department of Agriculture, to help farmers reduce agri-
 cultural runoff  and  issuing  permits for agricultural  discharges.

     At the local  level,  the Departments of Public Works for the
 City of Baltimore and  Anne  Arundel  and Baltimore  Counties  are
 responsible for  administering the regional stormwater management
 plan, which includes permitting,  inspecting, and collecting per-
 formance bonds.  In Anne Arundel County, the Department of Public
 Works and  the  Planning and Zoning Department share  responsibilty
 for the County's innovative  watershed  management program.   These
 agencies,  along with the Baltimore County Health  Department, also
 enforce nuisance  laws,  regulate  the  discharge  of liquids  and
 other offensive matter, issue permits  for disposal sites, require
 environmental impact statements  for subdivisions within the water-
 shed of any reservoir  used for  the public  water supply, approve
 or  disapprove the  subdivisions  within the  watersheds, and regu-
 late sanitary  landfills.   They   also  oversee  private water  and
 sewage disposal systems, conduct the day-to-day activities of the
 State Water Quality  Program,  review watershed  management  agree-
 ments, and develop and carry  out the master water  and sewer plans.

 Ground-Water.   OEP is charged with protecting underground sources
 of  drinking water from contamination.  It regulates the discharge
 or  disposal of waters  or wastewaters  into underground-waters and
 issues permits  for  ground-water  recharge  systems,  wastewater
 effluents disposed of  on  land,  and discharges of  leachate from
 landfills  to surface or ground-waters.   The Water Resources Admi-
 nistration issues permits  for ground-water appropriations.   The
 safety of the drinking water  is the responsibility of the County
Health Department in Baltimore  County and of the  Department of
Utilities  in Anne Arundel  County.  Drinking water  for Baltimore
                              11-11

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City and the  section  of Baltimore County in the core  study  area
is exclusively  from  surface  waters.   Some  residents  of  Anne
Arundel County  also rely on the metropolitan  water  supply  for
their drinking water.   Residents  of areas outside  the  core study
area draw their drinking water from ground-water supplies.

Surface and  Ground-Waters  Potentially Affected  by Activities
Associated with Generating Energy.  The Energy  Administration  of
the Department of Natural Resources is responsible for protecting
surface and ground-waters from activities associated with genera-
ting energy.   Its  responsibilities include  siting  power  plants
and writing permits for coal mining operations.

Regional Planning Relating to Water Use.  The  Regional  Planning
Council conducts areawide planning for the Baltimore Region.  Its
authority is based  partly on the  Clean  Water Plan  for the  Balti-
more Region adopted in  accord with the Federal  Clean  Water Act.
It develops policies  for implementation of the General Develop-
ment Plan  for  the  Baltimore  Region and coordinates intergovern-
mental planning. The  latter  involves  cooperative preparation and
amendment of the General Development Plan and the review of plans
arid projects  by State  and  local governments  which may have an
impact on the region.

Institutional Framework for Air Problems

     The State Office of Environmental Programs  has been delegated
the responsibility  for  enforcing  the Federal Clean Air Act in the
State of Maryland.  OEP also  has  authority for  adopting rules and
regulations regarding the control of statewide problems with toxic
air contaminants.   To ensure compliance with air quality standards
and regulations, it conducts  air monitoring, investigates  commer-
cial operations potentially  affecting air  quality, registers air
dischargers, issues annual  operating  permits  and permits  to con-
struct new facilities that may emit pollution to the  air, develops
plans for compliance, investigates complaints,  and  conducts perio-
dic inspections.  ~

     Monitoring air and enforcing compliance are performed  by both
State and local agencies. The responsibility for point sources is
divided between  State  and   local  authorities.   In  general,   the
State is responsible for monitoring compliance  at complex sources,
such as  bulk  petroleum  storage  facilities  and  major  chemical
plants, and for mobile  sources, such  as cars and trucks.

     At the local  level,  the Bureau  of Environmental  Services of
the Baltimore  County  Department of Health  and the Department of
Health of Anne  Arundel  County carry out the mandate  for protect-
ing air quality.  The responsibilities include  monitoring for  tra-
ditional air pollutants  (so-called criteria pollutants), regulat-
ing operations   involving  combustion   (such   as   incineration),
                               11-12

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 participating in program planning,  and monitoring compliance for
 sources that are a joint  State  and local responsibility and for
 sources that are designated  as strictly local.  The State carries
 out enforcement responsibilities  for Baltimore City.

 Institutional Framework  for  Land  Disposal Problems

      The division of  responsibilities  for regulating land dispos-
 al of wastes is  based primarily  on whether or  not  the waste is
 considered hazardous.  Regulating activities  associated with the
 handling and disposal of hazardous  wastes is the province of the
 State;  non-hazardous  wastes  that can be  disposed  of  in sanitary
 landfills  are the responsibility of local agencies.   Local agen-
 cies do,  however,  have  responsibility to  inventory  the types,
 quantities,  and destinations of hazardous wastes and regulate the
 primary generators  of hazardous wastes (chemical processing faci-
 lities).

      The specific hazardous  waste activities  and the State agen-
 cies responsible for  them  are:

     o  hazardous waste  siting,  which  involves  reviewing siting
        applications and  holding  public hearings—Maryland Hazar-
        dous  Waste Siting Board;
     o  regulation of  private hazardous  waste  disposal  sites,
        which involves  permitting and  monitoring  and  enforcing
        the Federal  Resource, Conservation, and Recovery Act
        (RCRA)—OEP; and
     o  cleanup  of  abandoned  and inactive hazardous  waste dumps
        and spills,  which involves administering  the  State Super-
        fund  program,  and permitting,  manifesting, and licensing
        all transporters  and  facilities that  store and dispose of
        hazardous  wastes—OEP.

      In Baltimore City,  the  Bureau  of  Solid  Waste in the Depart-
ment  of Public Works  has  the responsibility for collection of
seasonal wastes  and for land  disposal  of non-hazardous  wastes.
This  latter  responsibility  includes  the operation  of sanitary
landfills.   The  City  also has  oversight, through the Northeast
Maryland Waste  Authority,  over the operation of  two privately-
operated incinerators.

      In Baltimore  County,  sanitary landfills are regulated  by
the Baltimore County  Department  of  Health.   The  responsibilities
entail  monitoring solid  waste  facilities  and  enforcing rules and
regulations, helping  industry  in proper  disposal  practices,  and
regulating sewage  sludges that   are  not considered  hazardous.

     In Anne  Arundel  County,  waste management  is conducted by
four departments. The Bureau of Solid  Waste  of the Department of
Public Works  is  involved  with  constructing  and operating  the
                              11-13

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sanitary landfills.  The  Department of  Inspections and  Permits
issues permits  and  conducts  inspections  for  compliance  with
State and local  laws  and  regulations.  The Department  of Health
inspects for health violations.  Finally,  the  Department of Plan-
ning and Zoning issues special exceptions for landfills.

       All of  these State  and  local  agencies  involved  in  the
control of toxics and  the  protection of  the environment  are repre-
sented in the institutional structure of the Baltimore  IEMP.  The
nature of  this  institutional  structure  and  how it evolved  are
described in Chapter III.
                               11-14

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1. Baltimore City Planning Department, The Baltimore Book, p. 11
(1986).

2. Regional Planning Council, Growth & Impacts in a Maryland
Watershed; Urbanization in the Jones Fall, 1600-1981, conducted
as part of the Jones Falls Urban Runoff Project by Samuel Martin,
et al, p. 3 (1981) .

3. Maryland Air and Water Quality Atlas,  p. 43.

4. Maryland Air and Water Quality Atlas,  p. 45.

5. Maryland Air and Water Quality Atlas,  pp.45-48.

6. Regional Planning Council (1981), p. 25.

7. Ibid.

8. Regional Planning Council, 1982 General Development Plan;
Environment, p. 44 (October 19lJ2T"I            '

10.  The sources for the historical information are Regional
Planning Council's 1981 report for the Jones Falls Urban Runoff
Project, Growth & Impacts in a Maryland Watershed:  Urbanization
in the Jones Falls,  1600-1981, by Samuel  Martin, Roberto Arguero,
Jr., Virginia Driscoll, and Karl Weaver and Baltimore City
Planning Department's The Baltimore Book (1986).

11. Baltimore City Planning Department, p. 11.

12. Ibid .
                              11-15

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              CHAPTER III

      THE INSTITUTIONAL STRUCTURE
OF THE BALTIMORE IEMP AND ITS EVOLUTION

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       III.  THE  INSTITUTIONAL STRUCTURE OF THE BALTIMORE IEMP
                        AND ITS EVOLUTION
      This  chapter  describes  the management and the institutional
 organization  of the Baltimore IEMP,  the evolution of this arrange-
 ment,  and   public  education  and  involvement  in  the  project.

 RATIONALE  FOR THE  INSTITUTIONAL ARRANGEMENT

      EPA intends  that the  IEMP be  useful to public health  and
 environmental decision-makers  within State and  local  government
 agencies.   The EPA understands that  it  is these  individuals  who
 must  directly carry  out,  and are most affected by, environmental
 decisions.  Yet, State and  local decision-makers  are unlikely to
 accept  the  basic  IEMP approach and commit themselves to the suc-
 cess  of the  project  unless  priorities  reflect  State  and  local
 concerns.   EPA has,  for  this reason,  encouraged  the  active par-
 ticipation  by all  local  responsible  parties and  agencies  in
 managing and  coordinating the project.

      The Baltimore project  represents an  experiment  to test the
 hypothesis  that  local project control  of  the IEMP will  lead to
 active  participation  and  commitment by  State and local authori-
 ties.   Thus,   in  a  unique  partnership,  EPA  has  delegated  key
 decision-making authority  of  the   project  to  State  and  local
 officials.  In the section  of  this  chapter  entitled  "Evolution
 of the  Management  Structure,"  we explain  why the  EPA  decided to
 try this approach.

 THE INSTITUTIONAL STRUCTURE

     The lEMP's  institutional  structure consists  of  two  merge
 committees:   the  Management  Committee  (MC)   and  the  Technical
 Advisory Committee (TAG).  They also  represent the vehicles  for
 State and local participation.   EPA provides administrative, tech-
 nical,  and  analytical  support.   In  the  second phase of the pro-
 ject, additional  support  will  come  from the  Risk  Assessment
 Review  Panel, consisting  of experts  from the Johns Hopkins Univer*-
 sity.   It will advise the committees  on scientific and technical
 questions regarding  human health  risk  which arise  during  the
 project.  Figure III-l illustrates  the  organizational  relation-
 ships.

     The Management Committee (MC)

     The four  members of  the  MC  representing  the three  local
political jurisdictions and the  State are  drawn  from the follow-
 ing agencies:

       o   the Mayor's Office, City  of Baltimore;
                              III-l

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                    Figure ffl-1
                  BALTIMORE ffiMP
             ORGANIZATIONAL RELATIONSHIPS
           MANAGEMENT  COMMITTEE (MC)
  RISK-ASSESSMENT
REVIEW PANEL  (RARP)
        TECHNICAL  ADVISORY
          COMMITTEE  (TAG)
        EPA
     REGULATORY
INTEGRATION  DIVISION
                                       (RID)

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     o   the Office of the Baltimore County Executive;
     o   the Qffice of the Anne Arundel County Executive; and
     o   the Maryland Department  of Health and Mental Hygiene,
         Office of Environmental Programs.

These local  agencies  were  chosen because   they  represent  the
highest-level policy-making bodies  within their political juris-
dictions. The representatives were  selected  by the Mayor, in the
case of Baltimore  City,  and  by  the Chief Executives, in the case
of Baltimore and Anne  Arundel  Counties.   The Maryland Department
of Health and  Mental  Hygiene,  Office of Environmental Programs
is the  State agency  that customarily handles EPA  projects  and
that is concerned with issues involving human health.  The estab-
lishment of  the  MC  is  intended to increase the likelihood that
the work conducted by the project reflects the attitudes and con-
cerns of  greater  Baltimore  and  responds  to regional  and  local
needs .

     The MC's functions  include:

     o   managing and overseeing the IEMP,
     o   selecting the environmental issues upon which the pro-
         ject focuses,
     o   providing local guidance to EPA on political realities,
     o   determining project strategies,
     o   overseeing the development and implementation of work-
         plans ,                      v
     o   reviewing EPA analyses and recommendations , and
     o   issuing results and recommending control actions.

The MC does  not  determine the EPA1 s contribution  to the funding
of the project or the extent of other resources the EPA provides.
It does,  however,  control  the  allocation  of  funds among  IEMP
activities.

     The membership of  the MC is presented in Figure III-2.  The
MC chose as  its coordinator  Dr.  Max Eisenberg.  The MC generally
meets once a month or  whenever  a key  management decision must be
made.  For each meeting,  EPA staff prepare  an agenda and neces-
sary background documents.   Decisions   are  made  by consensus.

     The Technical Advisory Committee  (TAG)

     The TAG  advises  the MC  on  the technical  and  scientific
aspects of the project.  It  oversees and  comments  on all EPA and
consultant work for technical competence,  paying particular atten-
tion to methods, assumptions, monitoring  and modeling, and basic
technical approaches used in the project.  The TAG recommends and
suggests issues to study within the limits  of the resources and
schedule of the project.  For instance,  it identified the origi-
nal list of prospective issues for detailed IEMP study.  Finally,
                              III-2

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                           Figure III-2
Current Members of the Baltimore IEMP Management Committee

Mr. J.  James Dieter,  Assistant  Director,  Bureau of Environmental
     Service, Baltimore County.

Dr. Max Eisenberg,  Director, Science  and Environmental  Health,
    Science and Health  Advisory Group,  Office  of Environmental
    Programs Department of  Health  and  Mental  Hygiene, State  of
    Maryland.

Mr. Robert  Perciasepe,  Chief   of  Capital  Improvement  Program,
    Department of Planning,  City of Baltimore.

Mr. Claude  Vannoy,  Assistant to  the County  Executive for  Land
    Use, Anne Arundel County.


     Former members of The Baltimore IEMP Management Committee

Mr. Daniel Body represented Anne Arundel County.

Ms. Virginia Kearney represented the City of Baltimore.

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 serving  as  liaisons  to  others  in  the agencies  they represent,
 members  of  the  TAG  enhance  coordination  of the IEMP with ongoing
 projects at their respective agencies.

     A specific example  illustrates this  coordinating role. The
 question was  raised at a TAG meeting  if  any risk assessment had
 been made of pathogenic problems  arising  from  urban stormwater
 runoff in  Baltimore.   The  representative  from   the  Regional
 Planning Council  indicated  that  such a study  had  been done by a
 researcher  at Johns Hopkins  University,  who found that the  risks
 were low, even  though  the streams do not meet water quality  stan-
 dards for fecal coliform.  This  one, relatively small, example is
 but one  of  many instances  of communication and coordination that
 would not have  occurred or would have happened more slowly in the
 absence  of  the  TAG. (See  Appendix C for  other instances of for-
 tuitous  interplay among the participants.)

     The fifteen-member  TAG  is  composed  of  technical  managers
 from the Gity of  Baltimore, the two counties, the State, as well
 as representatives  from the Baltimore metropolitan area's Region-
 al Planning Council   and  the academic  community.   It  has  been
 designed  to help the  project  make  maximum  use of existing data
 and capabilities  within State and  local  governments  and   other
 area institutions.   The members are  experts  in  their  fields,
 which range from  geology  to  toxicology  to  engineering..  The
 members  of  the  TAG and their  affiliations are  listed in Figure
 III-3.

     The membership  of the TAG  was determined  in the following
 way.  The coordinator  of MC  compiled a tentative list of indivi-
 duals whose   skills and  interests  would  most likely match the
 advisory  needs.of  the MC.   This list was  reviewed,  amended, and
 then approved by  the  MC  as  a whole.   EPA staff  contacted the
 individuals on  the  list  and  solicited  their interest in joining
 the project in  an advisory role.  For individuals who declined or
 were unable, for  whatever  reason,  to  accept the invitation, EPA
 staff identified  alternative  candidates.   Final  selection  of
 alternative candidates was approved  by the Management Committee.

     The  Chairman of the TAG is Dr. Jared Cohon, Vice Provost for
 Research and Professor of Geography and Environmental Engineering
 at the Johns Hopkins University.  Vice-Chairman is Samuel Martin,
 formerly with the  Regional Planning Council  and  now a private
 consultant.  A  chairperson from  acaderaia  was selected to promote
 the impartiality of decisions.  The  TAC meets  as  often as deemed
necessary, which is generally  once  per  month.   Also,  for project
 coordination, the Chair of the TAC attends MC meetings.

     Though the  TAC   is  not  a   policy-making  body,  it  does
 incorporate policy  considerations  into  its  deliberations  and
makes recommendations  on policy  to  the  MC. The following example
                              III-3

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                            Figure III-3
     Members of the Baltimore IEMP Technical Advisory Committee


Don Andrew, Administrator, Engineering & Enforcement Programs,
    Office of Environmental Programs.
Charles Billings, PhD, Associate Professor,  Environmental Health
    Engineering, School of Hygiene and Public Health, Johns
   1 Hopkins University.
Philip Clayton, Manager, Cooperative Clean Water Program,
    Regional Planning Council.
Emery Cleaves, Principal Geologist, Maryland Geological Survey
    (Chairman,Ground-Water Subcommittee).
Jared L. Cohon, Vice Provost for Research, Professor of Geography
    and Environmental Engineering, Johns Hopkins University
    (Chairman).
N. Singh Dhillon, Director, Environmental Health, Anne Arundel
    County Department of Health.
Tom Ervin, Environmental Planner, Anne Arundel County Office of
    Planning and Zoning (Chairman, Ecological Subcommittee).
Katherine Farrell, MD. MPH., Chief Division of Environmental
    Disease Control, Office of Environmental Programs.
David Filbert, Director, Division of Air Pollution Control,
    Baltimore County Department of Health.
Frank Hoot, Assistant Commissioner, Environmental Health,
    Baltimore City Health Department (Chairman, Human Health
    Risk Subcommittee) .
Paul Keenan, Administrator, Pollution Control Section, Baltimore
    City Department of Public Works, City of Baltimore.
John W. Koontz, represented the Enforcement Program, Waste
    Management Program Administration, State of Maryland.
Sam Martin, Consultant (represented Regional Planning Council
    during Phase I) (Vice Chairman).
Janice Outen, Supervisor of Water Quality, Baltimore County
    Department of Health.
Colin Thacker, Director, Northern Environmental Services,
    Baltimore County Health Department.
Bill Wolinski, Water Quality Goodinator, Department  of Public
    Works.

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illustrates the  functional  overlap   between  technical  review and
consideration and recommendation of policy.

     Because scientific  data  vary greatly  in their quality and
usefulness in decision-making, decisions must often be made re-
garding whether  sufficient  evidence exists to support an analyti-
cal conclusion.   The TAC,  among whose  responsibilities   is the
review of  data   developed  for assessing human  health  risks,  is
therefore charged by the MG to determine  data quality  standards.
The TAC  identifies   situations where  science and  science  policy
converge (that  is,  where assumptions  must  be made to permit sci-
entific inferences  to be drawn on health issues of concern to the
IEMP) and makes  recommendations  to  the MC on how  these  science
policy issues should be  resolved.

     Many of the decisions  of  both committees must be  based upon
cutting-edge research  into  often controversial  health  issues.
The MC  established   the  non-governmental  Risk Assessment  Review
Panel to provide independent evaluations   of  these data and re-
lated analyses.  Scientists for  this  panel are  on the  faculty of
the School  of  Hygiene  and Public Health  of  the  Johns  Hopkins
University.  The panel's function is  to  review  the  interpreta-
tions of the data and the  assumptions  EPA  uses  in making  assess-
ments of risk to human health.   The  panel  is  not  responsible for
the quality or  appropriateness of the technical  data.  The ser-
vices of the panel  will  be  drawn  upon in  Phase  II.  The composi-
tion of the panel is presented in Figure III-4.

EVOLUTION OF THE INSTITUTIONAL STRUCTURE

     What began  as   a traditional  EPA project  in the  summer  of
1983 evolved into an experiment  in local  control  of a joint EPA/
State and  local government project.  To  test   the   hypothesis
that delegating  management  authority will lead   to active  local
participation and commitment,  EPA decided  to  shift gears  shortly
after starting the  project  and commit itself to  a nontraditional
EPA-State/local relationship.  The  management  structure   is the
product of a series  of meetings of EPA with State and local  offi-
cials working together  to  find  the  right institutional  formula
for the success of  the Baltimore IEMP.

     At the start  of the Baltimore  IEMP,  EPA  made all  the key
management decisions, with  limited participation  by State or lo-
cal authorities.  Yet EPA had not originally intended  State and
local involvement to be  so limited.  Instead,  the plan  was  to
have representatives  of  all  relevant  jurisdictions, as  well  as
EPA's Region III  and the Chesapeake  Bay  Program, participate in
a joint project management  team with staff from EPA headquarters.
These representatives would keep the  jurisdictions  informed and
the jurisdictions in turn would have veto  power over EPA's direc-
tion of the project.  Two  advisory groups  were also planned—one
                              III-4

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                            Figure III-4
            Members of the Risk Assessment Review Panel
Robert Frank, (RARP Coordinator), M.D., Professor,
   Department of Environmental Health Sciences,  Inhalation
  iToxicology.
Morton Corn, Ph.D, Professor, Department of Environmental
   Health Sciences, Environmental Health Engineering.
Edward A. Emmett, M.D., Professor, Department of Environmental
   Health Sciences, Occupational Medicine.
Gareth M. Green, M.D., Professor and Chairman, Department of
   Environmental Health Sciences
Charles A. Rohde, Ph.D, Professor and Chairman,  Department of
   Biostatistics.
Robert J. Ru£in, Ph.D., Professor, Department of Environmental
   Health Sciences, Toxicology.
David L. Swift, Ph.D., Professor, Department of Environmental
   Health Sciences, Environmental Health Engineering.
Melvyn S. Tockman, M.D., Ph.D., Associate Professor, Department
   of Environmental Health Sciences, Occupational Medicine.

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 for  scientific  advice,  to be  established  under the  auspices  of
 the  State  Governor's  Council on Toxic  Substances  and to consist
 of nongovernment  experts,  and  the  other for economic and regula-
 tory review.   In  contrast to expectations, this  initial manage-
 ment committee  convened  only _once--in  the  fall  of 1983--and the
 technical  committees did not meet at all.

      In  the  first few months after  the project  started, manage-
 ment decisions  were nevertheless being  made.   The IEMP developed
 and  executed  a technical work plan  and, by early 1984, produced
 a preliminary  data  base  on  air  emissions,  water  discharges,
 drinking-water  quality,  and  hazardous  waste characteristics. The
 State's  role was  limited to  providing  access  to  monitoring sites
 and  local  authorities  had yet  to be  brought into  the project.

      In  the winter of  1984,  staff  at EPA headquarters recognized
 that the absence  of involvement by  the management  committee  in
 the  oversight  and  conduct  of the technical  work made the Balti-
 more project  like any  other  EPA  project--EPA-controlled,  with
 little participation in decision-making by State and local autho-
 rities.  They  saw the  situation as  presenting a unique opportu-
 nity for EPA  to experiment with local  control,  relinquishing the
 authority  for key decisions regarding project direction and poli-
cies  and allocation of budgeted  funds.   Through  a novel institu-
 tional arrangement, EPA hoped  it could  effect an enduring multi-
 governmental structure that  could  effectively address such envi-
 ronmental  issues as cross-media transfers of toxic substances—an
 important  IEMP objective.

      Through the rest of 1984, management authority was gradually
 shifted  over to  a reconstituted Management Committee,  which had
 served initially  in  an  advisory  role  in  managing  the project,
 until the  committee acquired  the  responsibilities consonant with
 its  present role.  To  facilitate  the transition to local control
 of the project,  EPA hired a  risk  assessment  and management con-
 sultant  to assist in  the  formation  of the new  institutional struc-
 ture  and  to  advise local  management on risk assessment issues.
 Participation by  the State in the management committee was made
 contingent upon  participation by the local authorities.  To this
 end,  EPA had  to assure  all  entities that  major  management deci-
 sions would reflect  State and local concerns.  EPA did, however,
 reserve  the right to terminate the study at any  time if the ori-
 ginal objectives  of the  IEMP (as  stated  in Chapter  I)  wer"e not
 being achieved.  By this  condition,  EPA" made  clear that only the
means to  reach these objectives,  and   not  the  objectives  them-
 selves,  were being left  to local control.   EPA  retained Dr. Erik
 Rifkin who is  a professional  facilitator  and  expert  in risk com-
munication to  assist  in  this transition.   Dr.   Rifkin provided
 assistance to all the parties--EPA,  State and local officials--in
 clarifying questions,  suggesting solutions, and generally resolv-
 ing  concerns in a positive manner.
                              III-5

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     The first  order  of business  of the new  MC  related to  the
structure of  the  MC  itself.   EPA suggested  that  the  committee
elect a  chair,  but the  members  argued against  this  because  of
concern that the  appointed  person  could  exert unequal  authority
over the  other  jurisdictions  represented.    Committee  members
agreed that a  chairperson  was not needed because  of  the  small
size and  closeness  of the  group.   Designation of a  chairperson
would also  incorrectly  connote a position of  power or  authority
to the jurisdiction  represented  by the person serving  as  chair-
person.  Any documents  produced  by  the  project  and  bearing  the
name of  the  MC  chairperson  could  be   erroneously   viewed   as
imparting sole  authorship.  This would not be  a  true  representa-
tion of  the equal decision-making  status  among the participating
governments — a  condition  agreed   to  by  all  governments  before
their participation.  Instead, they  agreed  upon  a State  repre-
sentative (Max  Eisenberg) as coordinator  to  facilitate communica-
tion and arrangements within the committee.

     The TAG, too, was  concerned about one  jurisdiction's having
undue influence on decisions  of the committee.  Nevertheless, it
recognized the need for a chair because of the  size of the commit-
tee.  To resblve this  dilemma, the TAG formed a nominating commit-
tee for  the chair.   An academic  representative  (Jared  Cohon),
believed to  be more  impartial  in  jurisdictional disputes,  was
chosen to promote a neutral perspective.

     To  facilitate  coordination with the  TAG,  the  chairman of
the TAG  was to  attend MC meetings. Finally,   the MC decided that
the TAG  would  provide only advice on  technical  matters and make
recommendations on  key  decisions,  but not  have  authority  over
direction of  the  project.   Final authority on all key decisions
was reserved for the  MC.

     The TAG did not  always meet as one group.  The TAG eventual-
ly spawned  subcommittees to improve the TAC's  ability to review
and discuss a wide range of issues.  Prior to  forming the subcom-
mittees however,  the  TAG spent  several  months  working .together
to identify  issues,  agree  on  a  procedure  for evaluating issues,
selecting issues  for  further  study  and  creating the appropriate
subcommittees.  The  subcommittees  analyzed,  discussed  in detail,
and ranked  issues that had  been  grouped  according to  the kind of
environmental impact  that   they  implied.   The  whole TAG  did a
final ranking to  recommend  issues  to the  MC.   [In Chapter IV  and
Chapter VIII,  we describe  the  priority-setting  process.]    TAG
members volunteered  for one  or  more  of the  subcommittees.    In
his function as chairman, Jared  Cohon  chose  subcommittee chairs.
The "issue" subcommittees met for four months during the Phase I
analysis.
                               III-6

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 PUBLIC EDUCATION AND INVOLVEMENT

     The general public  was  kept  informed of the progress of the
 project through educational outreach efforts. Status reports were
 periodically sent  out   to over 250  groups and  individuals  on  a
 local mailing  list.   Also,  in June  1985,  the  IEMP  held  a public
 seminar attended  by  roughly  150  people  to  inform  the  public
 regarding project  methodology, status  of  the  project,   and  the
 issues under review for Phase  II study.

     In the concluding stage  of Phase  I,  the general  involvement
 in the IEMP widened through  membership  in workgroups  established
 to develop workplans for Phase II issues — that is, after the ini-
 tial 32 issues had been  screened  and Phase II issues  tentatively
 identified.  Though chaired  by TAG members,  the  workgroups  were
 comprised of   representatives  from  industry,  public  interest
 groups, government, and  acaderaia,  amounting to  nearly 60 people.
 A list of  these  individuals and the agencies  and interests  they
 represent (who were not  already  listed on  the  TAG  list)  is  pre-
 sented in Figure III-5.

     The government participants  in the  project recognized  the
 need for  and   the  benefits  of direct  public  participation  and
 other types of public  involvement in the  project.  However,  for
 many reasons,   they were  unsure  as  to  when  the .  public  should
 participate.

     First, the  TAG  as  a  committee of  the whole,  viewed  the
 project as  atypical  of  other environmental  projects.   The  TAG
 had identified 32 issues of potential concern*  Before the actual
 screening of issues,  no  one could  possibly know which  of  these
 would be selected  for Phase  II study.   Because  objectives speci-
 fic to issues  were as  yet undecided, the  TAG  could not  communi-
 cate work plan objectives and  the  expected results.  This situa-
 tion Tvas completely unlike  the development of  local  waste  water
 pretreatment ordinances,   for  example,   where  there is  only  one
major issue to  be decided  and work steps are  fairly  evident.

     Second, the  large  number of  issues  for  potential  study
 presented a difficult situation into which to invite  public par-
 ticipation.  The range  of  identified  topics covered  almost  all
 locally important environmental issues.   To give equal  treatment
 to each issue, as  well as  to  be  fair to  the  local constituency
 that inevitably develops  around  specific  issues, the TAG  would
have had to  invite all  interested  groups  to  participate.   This
obviously would have  increased the number of project participants
by.several dozen.  The coordination, communication, and  logisti-
cal complexities  of the project would have increased several-fold.

     Finally,  the TAG realized that  the project  could not afford
 to carry all 32  issues  into Phase II.  As  a  result of priority-
                              III-7

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                            Figure III-5

         Additional Participants in Phase I Baltimore 1EMP
               Through their Membership on Workgroups
Anthony S. Bonaccorsi
Eastern Stainless Steel Company

Daryl Braithwaite
Clean Water Action Project

Midhael K. Hettleman
The Southern Galvanizing Company

Genevieve M. Matanoski
Johns Hopkins School of Hygiene and
  Public Health

Darryl W. Palmer
FMC Corporation
             %-
Susan S. G. Wierman
Office of Environmental Programs,
  State of Maryland

Bruce Windsor
American Lung Association of Maryland
                r
Joe Macknis
U.S. EPA Cheaspeake Bay Program

Rich Batiuk
U.S. EPA Chesapeake Bay Program

Mary Jo Garreis
Office of Environmental Programs, Maryland

Mary DoIan
Baltimore City

David Carroll
Baltimore City Department of
  Planning

Stuart May
Dept. of Natural Resources, State of
  .Maryland

Harold M. Cassell
Dept, of Natural Resources, Maryland

-------
Ajax Eastman
State Water Quality Advisory
  Council

Daryl Tuckey
Bethlehem Steel Corporation

Bill Burgess
Department of Natural Resources,
  Maryland

John Hobner
Baltimore County Health Department

Edwin C. Weber
Department of Natural Resources,
  Maryland

Tom Kusterer
Office of Environmental Programs,
  Maryland

Bernard Bigham
Office of Environmental Programs,
  Maryland

Mark Farfel
Johns Hopkins University

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setting, roost issues would not be further assessed after Phase I.
To invite numerous  members of the  public  to become  involved  in
the project and to  ask them to spend  much  of their uncompensated
time and energy in screening all 32 issues  only to have the issue
of most interest to them not be selected for further analysis was
viewed as unfair and frustrating.

     The TAG  therefore  decided  first  to   select  the  Phase  II
issues of most importance, and then to invite members of the pub-
lic to- participate  in  the workgroups established  for each Phase
II issue.  Questions of  the scope  of the  study,  objectives, and
results could then be adequately addressed.
  \
     In Chapter IV,  we present  the 32  issues  identified  and an
overview of the methods  used  to  set priorities among the issues.
We also discuss how these methods were developed.
                               III-8

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               CHAPTER IV




OVERVIEW OF THE PRIORITY-SETTING PROCESS

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            IV.  OVERVIEW OF THE PRIORITY-SETTING  PROCESS
     This chapter discusses the procedures  the  Management  Committee
and Technical Advisory Committee used to set  priorities  among  envi-
ronmental issues  in  the Baltimore  area and to  choose  issues  for
more detailed analysis in the second phase  of the IEMP.  The impor-
tance of this priority-setting exercise extends beyond the  relative-
ly narrow  purpose of  defining  study  topics  for this particular
project.  The techniques described  here are applicable to ongoing
environmental decision-making in the Baltimore area and they could be
applied to other metropolitan areas  as well.

   N Decisions about resource  allocation for environmental protection
are always made within the  context set by statutes, public concern,
and limitations of scientific data and understanding.  The  decisions
made in the Baltimore project were no exception.  Within that frame-
work, the primary criteria  for the making of such decisions require
the best scientific evidence that governments  can  bring to bear on
particular problems.  Often these data are scarce, poor  in quality,
or unavailable.   Priority-setting for the purpose of resource
allocation is thus an exercise in decision-making under uncertainty.
             V-
     It is  important to  keep  in  mind  that  the  priority-setting
for the  Baltimore IEMP was  conducted  primarily   on  the   basis
of available information,  supplemented by data from a brief ambient
air monitoring  effort  conducted by the EPA.   Although  EPA and the
state and local governments who managed the project used scientific
information, the  priority-setting  was  not  a  strictly  scientific
enterprise.    Rather, it was an exercise in policy analysis  using
analytic tools; reasonable  assumptions, where gaps in data existed;
and scientific  reasoning.    Products  included  a  series  of  policy
analyses and  a  set  of issues  for  detailed investigation in the
second phase of  the  project.  It relied heavily  on  the scientific
and technical  judgment  of  the  officials who sat  on  the  project's
committees.  And where the  project lacked data  or objective measures
against which to compare issues and problems, the members attempted
to make their valuations reflect local social concerns and priorit-
ies.

     The process for setting priorities developed  by the participants
of the  Baltimore project  straddles  the distinction that EPA has
often drawn between risk assessment and  risk  management.  Scientific
considerations played a  central role  in  determining the  project's
priorities, but the committees also considered policy and economics
in making their judgments.  For  the most part, however, the distinc-
tion between  use of  science and  basing  decisions  on policy was
preserved by the  use of "primary" decision  criteria which heavily
relied upon  scientific data and "secondary"  criteria which drew
on pragmatic  considerations  by local officials  regarding the best
use of study resources.
                                IV-1

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GENERAL STRUCTURE OF THE PRIORITY-SETTING PROCESS

     The priority-setting  process  in the Baltimore  IEMP  which the
TAG developed and implemented (illustrated in Figure  IV-1) comprised
the following steps.  First, the TAG members defined the geographic
boundaries of  the  study  and set  some preliminary,  and  flexible,
rules regarding  its scope.  Second, the  TAG identified thirty-two
potentially  important  environmental issues,  drawing heavily  upon
the members'  experience  and knowledge of potential  problems.  tThe
list is shown  in Figure  IV-2.]   Third, the  committee agreed on the
use of  three  separate measures  of  environmental  degradation  by
which to  evaluate the severity  or significance of  the thirty-two
issues.  These   measures   (or  primary  selection  criteria)—human
health risk,  ecological  impact,  and ground-water resource impact—
also would serve as the  "common  denominators"  to define a  set  of
reference categories into which each of the thirty-two issues would
be placed.   The TAG established subcommittees to apply or,  where
necessary, to develop  the  appropriate  methodologies for evaluating
the issues  in terms of  the three  measures.   It  then  placed each
issue into the  reference category  in  which  the  members deemed the
issue most appropriately belonged.

    Drawing  on their expertise  and the analytic resources provided
by EPA, each of the subcommittees  assessed  the  appropriate subset
of the thirty-two issues.  [For example, the ecological impact sub-
committee assessed only those issues clearly pertaining to ecological
issues.] From time  to time  during  their application of  the three
methodologies, the  subcommittees   requested  EPA  to  gather  more
information  or to analyze issues for which the scientific data were
particularly ambiguous.

    Following this  work,  each  subcommittee reported  to the  TAG  on
the most pressing problems as defined  by  primary criterion  used  by
the particular  subcommittee.  The  TAG  as a  whole  consolidated and
regrouped the topics,  and applied  a set of secondary  criteria  to
each of them based on economic and  policy considerations.   Finally,
the committee drew up a workplan for the project's second phase for
each of the  five "study  topics"  that had emerged  from the priority
-setting process.

    The charge of each subcommittee was to set priorities among the
issues and  recommend  before the  full TAG  the  issues  warranting
further study in Phase  II.  To do so, the TAG  believed that they must
reduce the list  of  possible  topics  from thirty-two to about ten  or
eleven.  The TAG intended to use meetings of the full TAG to arrive
at a consensus  about  the most  important problems and  thus reduce
the number  of study  topics to  about  five, the  number that the
project's managers  felt   could  reasonably  be  analyzed in  detail
during Phase II of the project.   Because of overlaps among the issues
recommended by the  various  subcommittees, this  second  step in the
priority setting  process  turned  out  to  be  less  difficult  than
originally thought (See Chapter VIII for a more complete discussion

                                IV-2

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                           Figure IU-1

                         Baltimore IEMP

                      Priority-Setting Process
 Selection of
  Study Issues
  Selection of
     Secondary
    Criteria
                      Definition of Project Scope
                                and

                       Geographic Boundaries
    Rankiny against
   Secondary Criteria
   fr Selection of
     Phase II Issues
Deuelopment of
Phase II UJork plans
    fr Budgets
Redefinition of

 Study Issues
 Rankiny
   ayainst
 Primary
     Criteria
   Re definition
     and
   Re ran king of
    Metals Issues
 Negotiation)
 of IVorkplan	»
  Rudyets
      Selection of
        Primary
        Criteria
       Data-
         Gathering
         (by EPfl)
            I
     Deuelopment of

     Priority-Settiny
        Methods
Recommendations on
 Phase II Issues,
 UJorkplans, ff Budgets

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 of this.).
     The  Management Committee, although responsible for the
 overall  direction of the study,  gave the TAG members broad authority
 in devising and implementing this  strategy.  The MC  reviewed the
 list of  thirty-two issues,  the decision to use. three primary criteria
 and their   associated  analytic  methodologies,  and  the  ultimate
 decisions on  priorities  that arose from the process.   The chairman
 of the TAG  attended nearly every meeting of  the Management Committee
 to discuss  the analytic work of the study and the policy implications
 of the analysis.  The Management Committee1 s role was not exclusively
 one of  delegation and  oversight;  the  committee took the  lead in
 matters  of  public participation  in the  study,  and also coordinated
 external reviews of the project's work.

     Consensus and professional judgment  played critical roles
 throughout  the  priority-setting  exercise,   both  for  the Management
 Committee and for the  TAG.  Neither committee,  as  a  rule,   took
 formal votes,, preferring instead to debate  issues until a consensus
 became clear.   The consensus was not always unanimous, but both
 committees  were  able  to arrive  at  decisions without  using formal
 mechanisms  like voting.   Partly because of this open structure and
 partly because  of limitations in the  data and in scientific under-
 standing of  environmental  problems,  the   MC  and the TAG  relied
 heavily upon  best professional  judgment to overcome  obstacles to
 agreements.

 PRIORITY SETTING IN PRACTICE
     The priority-setting procedure which we  described in the preced-
 ing  section did not exist at the outset of the process.   The committee
 members developed the methods as  they  proceeded,  taking into account
 the  particular  environmental problems   of  the  area,  the  project
 budget and  time constraints, and limitations in the data base.  The
 committee tried several different ways of setting priorities before
 arriving at the methods it  ultimately  used.   These different schemes
 are  discussed in more  detail below.  Also the chronology of decisions
 did  not  happen  as  one  might infer  from  the  description  of the
 priority-setting process.   Furthermore,  the distinctions  between
 various stages  of  the priority-setting  process  were,  in practice,
 not  clearly drawn.  Some issues regarding the analytic scope of the
 study (e.g.,  the  inclusion  of certain pollutant  classes)  were not
 finally resolved  until  the  end  of  the   project's  first  phase.
 Similarly,  the  secondary  criteria  of  pragmatic  considerations,
 rather than being  applied  all  at  once  at  the  end  of  Pha-se   One,
 actually played a  role from  time  to  time  throughout  the analysis
 described in  this  report.    This again   was  a  product of the   fact
 that the IEMP was not  a formulaic academic exercise but a real-world
 attempt to  set priorities and solve problems.   Adherence to a  more
 rigid decision-making  structure  would   probably  have reduced the
 amount of debate  on these  issues,  but  in  doing so it  would  have
 impeded the creation of  informed consensus  on which  the success of
 the project rests.
                                IV-3
•IIP

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PRELIMINARY DEFINING OF THE SCOPE OF  THE STUDY

     When EPA  originally  approached  the  state and .local govern-
ments in the  Baltimore  area with the idea  of  conducting an  IEMP,
it had in mind  a  project devoted  primarily  to the study  of toxics,
focusing primarily  on  human health  effects.   Initial discussions
among the various governments strengthened  EPA's decision to  focus
on toxics.  The major  considerations were that  conventional pollu-
tants (e*g.  biological oxygen demand in water, oxides of nitrogen
and sulfur in air, etc.) had already  been well  studied in the  study
area, and IEMP  was  unlikely to be able  to contribute  significantly
to their analyses or to strategies for  their control.   Accordingly,
the decision  not  to consider  conventional air pollutants was  made
by consensus of the various parties before the  Management Committee
and TAG ever formally met.

     The same  discussions, however,  led  EPA  to  reconsider  the
notion of  concentrating primarily on  human health  effects;   from
the outset of the project,  state and  local officials  were convinced
that the project  needed to include  ecological  effects as well  in
order to be useful.  Because of their importance  on marine ecosystems,
conventional water pollutants were included in  the study—again by
consensus before the establishment of the committees.

     The governments also  agreed at  this  stage to exclude radio-
nuclides and  pathogenic micro-organisms, episodic  events such  as
spills and sewage  treatment plant upsets,  occupational  exposures,
and exposures through the food chain (except those involving  locally
harvested seafood).  The reasons, in each  case,  were that the data
were so  limited that no useful  analysis could be expected within
the time and  budget constraints  of  the project,  that none of the
governmental agencies  involved  in the  study had any jurisdiction
over the problems, or that the issues were such that the site-specific
methodologies used  in  lEMPs were  not appropriate for the analysis.
An example of the last case is the food chain: analysis of exposures
to toxics through food  would require consideration  of the interna-
tional food  supply  and distribution network  and thus  seemed  an
inappropriate topic for the IEMP to consider.

      Some of  these decisions  on exclusion  of  certain pollutants,
sources, or  exposure  pathways  were debated again  after the TAG
began its deliberations, although none  was  changed as a result of
those discussions.   The decisions on the  scope of the  study were
not formally  made  by the  TAG  until  a  considerable  time after the
project began.

      Finally, another  important decision  that had  to  be made at
the outset  of  the  study  concerned  the  geographic   boundaries  of
the study.   Pollutants are 'bound to  cross arbitrary boundaries.
The problem was this:  to define a small enough  area such that the
                                IV-4

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 project could   contribute  to  the  understanding of  its  problems
 without making  the  area  so  small  that  pollution  "imports"  and
 "exports" have  a greater  impact on  the area  than the  effect of
 locally generated pollution.

      EPA consulted  with the  state  government to arrive  at tenta-
 tive boundaries which  included  the  city  of   Baltimore  and  its
 immediate suburbs.   It  then  discussed  these proposed  boundaries
 with the local  governments.  [The  boundaries  that  resulted  from
 the process  are shown  in  Figure II-l  in Chapter  II.]   The major
 issue in the  selection of  boundaries  was  whether  the  suburban
 areas in eastern Howard County should  be  included  in the study.
 After consulting with  Howard County, State,  and Regional Planning
 Council officials,  EPA decided  not  to  include  those areas.   The
 sources of possible  pollution were not  seen  to  be  as concentrated
 in  these areas  as  in the  other two counties or the  city.  Every-
 one Jagreed  to  reconsider  the decision  should  a pollutant source
 in  that jurisdiction become  important  to the project.  Also agreed
 to  was  the  decision to  include within  the  project  scope  of  any
 area in Anne Arundel or  Baltimore  Counties  which might  later be
 deemed  important to  completion  of  the project.  [For  issues  con-
 cerning underground  storage tanks, all of these two counties would,
 in  any  case, be included.]

 SELECTION OF THE INITIAL LIST OF PHASE I STUDY ISSUES

      After having  established  the  geographic  boundaries  for  the
 study and  deciding  to  focus  primarily  but not  exclusively,  on
 toxic pollutants, the Technical  Advisory Committee drew  up a  list
 of  thirty-two topics for preliminary screening.   In doing so,  they
 relied  heavily  on their previous experience with pollution problems
 and on  professional  judgment.

      The development  of the  list  took  many  months.   The  TAC's
 chairman asked  each  member of  the  committee to identify  at  least
 one issue that he or she thought was  especially worthy of considera-
 tion, and at least  one other issue whose importance had been under-
 estimated in the past.   Each  member was explicitly  instructed to
 indicate whether or not the issues were in the individual's area of
 expertise or under the  jurisdiction  of his  or her  agency.  Several
 committee members raised more  than  two issues,   often  from outside
 their own agencies'  jurisdictions.   The  chairman himself  did  not
 raise any issues.  EPA  staff  compiled  the  lists and  used them to
 develop the list of thirty-two that ultimately emerged.

      This process was neither  designed nor  ever  intended  to'inden-
 tify  systematically  every  environmental  problem; no  process  could
 do  so  given  data  limitations.  There  may  be  other, more  severe
problems which  have  not been  acknowledged because  data  on  expo-
 sure, toxicity,  or both are absent.   This  is a pervasive problem
 in  environmental or public health protection, one which will never
be  completely solved.   For this reason,  it is impossible  to  state
                               IV-5

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that the thirty-two  issues  are a  comprehensive list  of the most
pressing environmental problems in  Baltimore.   The process  estab-
lished by  the Baltimore  IEMP will,  however,   put agencies  in a
better position to appraise and solve any  new problems that  emerge
as additional data come to light.

     The issues raised by the TAG  can be grouped  into three broad
categories: 1) issues  defined by  pollutants,  2) issues  defined by
source or  source  category,  and  3) issues defined  by  environmental
medium or  exposure  route.   The  list  of  issues  ultimately  deve-
loped by the TAG is shown in Figure IV-2.

     The MC  reviewed the list and concluded that  it covered  the
most important environmental  issues  in  the  study  area.   It  could
thus serve  as  the  basis   for  the  priority-setting  that  was to
follow.  The  Management  Committee's  review was  principally  con-
cerned with  making  sure  that  no  potentially  important  problem
known to them had  been omitted and  that issues would be of area-
wide concern.  The fact  that the  MC proposed no  additions  to  the
list is  evidence  of the  degree  of  consensus that  exists  among
governmental officials about  the  principal  environmental problems
of the Baltimore area.

METHODS FOR SETTING PRIORITIES

     While developing  the  list,   the  TAG  made  two  preliminary
efforts to  set priorities  among  the  issues  it  was  identifying.
After the  committee had  prepared an  early version  of the issue
list, its  chairman consolidated  the issues into four  main  groups:
toxic air  pollution, indoor  pollution,  drinking  water  (including
groundwater), and  the  Baltimore  Harbor.   Hazardous  waste was  not
included as  a separate issue  group, but  various  impacts  attribu-
table to hazardous waste  (e.g.,  on air  toxics  or  water  quality in
the harbor) were included in the appropriate group.

     The chairman  then asked  each member to consider  three crite-
ria for priority-setting: human health effects, ecological effects,
and economic  impacts.   He asked  each  of the committee  members to
rate each  of  the four issue groups  as having high,  medium,  or low
importance when  considered  according to  each criterion.   Thus,  for
for example,  a committee  member  might  say,  "Toxic  air pollution
has high importance  for  human health, but  low  importance  for eco-
systems.   It  has medium  importance  in  terms  of   its  economic im-
pacts.  Indoor  pollution  is  of  low  importance  under  all three
criteria," and so  on.

     While this  method revealed  a great  deal  about  the  judgment
of the  various  committee members,  it  did not  result  in consensus
on the  importance of  issues.   Each of  the groups  was  considered
by most  members  of  the  committee to be extremely important under
at least  one  of  the  criteria.   Further,  committee  members dis-
agreed about  the  relative  importance of the  criteria  themselves
The issue  groups  were broad  enough that  each included many in-
                                IV-6

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                            FIGURE IV-2
                   THE INITIAL LIST OF 32 ISSUES
                  CONSIDERED IN THE BALTIMORE IEMP
 ISSUES SPECIFIC TO A POLLUTANT OR POLLUTANT CLASS (8)
 ACID RAIN
 ASBESTOS
 BENZENE
 MULTIMEDIA
      METALS
 PESTICIDES
Acid rain is acid precipitation in the form of
rain.1   Transformation products of oxides of
nitrogen (NOx) and sulfur (SOx), which are emitted
into the air through combustion of fossil fuels by
industrial facilities or even cars and trucks,
render precipitation more acidic.  Acid rain
threatens damage to lakes, forests, soils, and
crops.2

Asbestos is the popular name for fibrous minerals
used for fireproofing and heat insulating
material.3  Exposure to asbestos has been linked
to a respiratory disease called asbestosis and to
lung cancer.

Benzene, a volatile aromatic hydrocarbon proven to
be a human carcinogen, is an important industrial
solvent and constituent of gasoline.

Large amounts of metals are used in industrial
processes in the Baltimore area. Unlike organic
compounds,  metals do not decompose in the
environment and are found in all environmental
media.   Some metals, like lead, have been used in
household materials and are known to contaminate
drinking water and the indoor environment.

Pesticides,  especially herbicides, are used in
farming and smaller-scale operations, such as golf
courses and homes and gardens.  Pesticides in
agricultural and urban run-off may contaminate
surface and ground water.  Aerial spraying may
contaminate the ambient air.
IPOLYCHLORINATED
   BIPHENYLS     Polychlorinated biphenyls (PCBs)  are a highly
                toxic,  persistent group of organic compounds that
                may pollute  all environmental  media.  Their
                primary use,  until their banning by Congress,  had
                been as insulating material in such items as
                electrical transformers.

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TITANIUM       Titanium tetrachloride is produced by the
TETRACHLORIDE  atmospheric transformation of titanium dioxide,  a
               white, metallic pigment inadvertently emitted into
               the ambient air in manufacturing processes.  Clouds
               of titanium tetrachloride can be both a traffic
               hazard and a respiratory irritant.

VINYL CHLORIDE Vinyl Chloride is a volatile chlorine organic
               compound that is used in large amounts in the
               production of polyvinyl chloride  (PVC).  It is a
               known human carcinogen.

ISSUES SPECIFIC TO A SOURCE OR SOURCE CATEGORY  (16)

SEWAGE TREAT-
 MENT PLANTS   Sewage treatment plants often receive large
               quantities of volatile organic compounds, heavy
               metals, and other potentially toxic pollutants
               from industrial facilities and commercial users.
               These pollutants can be released  into the ambient
               air, surface, or ground waters.

LEAKING UNDER-
 GROUND STOR-  Chemicals, such as gasoline, contained in
 AGE TANKS     underground storage tanks  (USTs)  can leak out and
               contaminate ground-water or even  cause explosions.
               Of particular concern are the thousands of tanks
               connected with automotive service stations.
INCINERATION
OF SEWAGE
  SLUDGE

SANITARY
 SEWER OVER-
   FLOWS
"Toxic  substances contained in  sewage  sludge may be
 emitted into the air during  incineration.
 During periods of high- rainfall, the  capacity
 of  the sewer system  is not  sufficient to  accept
 all sewage.  Some sewage may  flow  directly to  the
 harbor or  its tributaries.
SURFACE IM-    Surface impoundments may release pollutants to the
POUNDMENTS FOR ground-water.  Impoundments that contain volatile
HAZARDOUS &    compounds may release them to the air.
NON-HAZARDOUS
WASTES
SEPTIC TANKS
 Septic tanks  can release large amounts of nitrogen
 to the ground water.  Nitrogen may form nitrates,  a
 potential  health risk to children from drinking
 water.   Septic  tanks  that contain cleaning
 solvents may  also release these to the ground-
 water.   Pathogens,  which can also move from septic
 tanks to ground water,  were explicitly excluded
 from consideration.

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 FEEDLOTS
AIR AND WATER
POLLUTION •.
FROM  FARMING
NON-POINT
WATER  DIS-
CHARGES

LANDFILLS
COMBUSTION  &
INCINERATION
POWER PLANTS
EMISSION OF
GRAIN FUMI-
GANTS FROM
SHIPS AND
GRAIN ELE-
VATORS

WASTE-WATER
DISCHARGES
FROM SHIPS

HARBOR SEDI-
MENTS
 Feedlots, that is, areas where large numbers of
 animals are raised and fed, produce great amounts
 of  animal waste.  These wastes, in turn, can
 pollute ground or surface waters.

 Air and water pollution from farming can include
 pesticides in the ambient air from aerial spraying
 of  pesticides and nitrogen fertilizer in
 agricultural run-off.

 Stormwater or agricultural runoff can carry high
 levels of pollutants to surface waters, such as
 streams or the harbor.

 Municipal and hazardous waste landfills may
 release pollutants to ground-water or surface
 waters.  Volatile organic compounds contained in
 the sites can be released into the air.

 Combustion and incineration can release a variety
 of  toxic compounds into the air.  Examples of
 where combustion and incineration occurs are wood-
 burning stoves, cars and trucks,  sludge
 incineration, and hazardous waste incineration.

 Power plants emit SO2 and heavy metals
 to  the air and a large variety of compounds to.
 surface waters.

 Pesticides, particularly grain fumigants, which
 are used to kill insects that feed on grain, may
 be  released and thus pollute the ambient air.
Ship sewage and contaminated water used to clean
ship bilges may be released and thus pollute the
harbor waters.

Pollutants in the sediments of the harbor may harm
organisms that live in or close to the floor of
harbor—particularly if the sediments should
become disturbed, such as through dredging.'

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ROAD SALTING
Salts from the salting of roads may pollute ground
or surface waters.
ISSUES SPECIFIC TO AN ENVIRONMENTAL MEDIUM OR EXPOSURE ROUTE (8)
TOXIC AIR
POLLUTION
WATER DIS-
CHARGES TO
THE HARBOR
Toxic chemicals may be released into the ambient
air from factories, cars,  trucks,  and even
neighborhood dry-cleaning establishments.  As used
here, the term does not refer to "conventional"
pollutants, such as oxides of nitrogen or sulfur,
carbon monoxide, or ozone.

This issue covers both point and non-point source
discharges to the harbor.
SURFACE DRINK- Drinking water for most of the population in the
ING-WATER      study area comes from surface waters.   Quality is
QUALITY        defined in terms of the concentrations of various
               pollutants, including disinfectant by-products,
               in the drinking water.
WATER QUALITY
OF CITY
STREAMS
Pollution in city streams may pose risks to both
the biota inhabiting the streams and people who
use the streams for recreation.
BIOACCUMULA-   Certain pollutants may accumulate in
TION OF TOXICS fish, crab, and other biota inhabiting the surface
IN FISH        waters of the study area.  These fish and crabs
               may,  in turn, pose health risks to humans,
               particularly should they be eaten in large
               quantities.
EFFECTS OF
POLLUTANTS ON
AQUATIC
ORGANISMS

CHROMIUM IN
THE HARBOR
AREA
Pollutants in the harbor may harm aquatic
organisms.
In past years, large amounts of chromium-
containing waste were used as fill  in areas
surrounding the harbor.  It is unknown to what
degree this fill has leached chromium to the
harbor water and sediments.

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INDOOR AIR     Pollutants from a wide variety of sources indoors
PpLLUTION      can degrade the indoor environment.   The
               pollutants include many of the same chemical
               compounds of concern in the ambient air, such as
               lead, formaldehyde, chloroform, and the products
               of incomplete combustion (PICs).   A chemical of
               unique concern to the indoor environment is radon.
     Webster's Ninth New Collegiate Dictionary. Merrriam-Webster,
     Inc., Springfield, Massachusetts (1983),  p. 52.

     Council on Environmental Quality,  Environmental Quality-
     1980. p.4.

     Van Nostrand's Scientific Encyclopedia,  fifth edition, Van
     Nostrand-Reinhold Company, New York (1977), p.198.

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dividual issues,  some of  which  were  seen  as  important,  others
as not  so  important.   Finally,  the  committee members  felt .that
they did  not have  sufficient  information to make - judgments a-
bout the  importance  of   various   issues,  especially  for  topics
outside their professional expertise.

     The committee,   therefore,  adopted  a second  approach.   It
requested EPA  to write  short  issue  papers  describing  what  was
known about  each of  the  32  issues as  background information  for
its deliberations.   For  reasons  of time  and resources  and  also
because the  importance of  a number of  issues  required no  further
elucidation,  the  EPA  prepared drafts  for only  about  a  third of
the issues.  Upon receipt of  these,  the  committee  requested  revised
versions of  most of  the  papers,  often  with   specific  suggestions
about further  information  that  could be included.  The  committee
members also pointed out the need for making explicit the assumptions
in the  papers,   explicitly  identifying  the  populations  at  risk,
fully documenting analytic methods  and  sources of data,  providing
maps, and preparing the papers in  a consistent format.  Because of
budget constraints,   none  of  the  papers  were ever  revised  upon
subsequent review by the committee members. Nevertheless, comments
on these papers  were taken  into   account  in later  analyses.   A
sample issue paper is provided in  Appendix B.
              V
     Drawing upon the information  in  the  issue  papers  and  what
was generally known about the other issues, the committee  attempted
to assign each of the 32 issues  to one of four categories:  (1) good
data indicating high  risk, (2) apparently high risk, but  with weak
data, (3)  apparently low  risk,  and  (4)  unknown.   Risk  in  this
context included  both health  and  ecological  risk, as well  as risk
to resources such- as aquifers and  bodies of surface water.

     This approach,   like  the first,   increased  understanding of
the issues,  particularly  those which  lay outside each  committee
member's expertise.    Like the first approach,  however, it  did not
lead to a  consensus  on the relative importance of various  issues.
The committee found  it  difficult  to  compare  problems  with little
data with problems for which data were  abundant,  and the  "unknown"
category presented  further  problems.   The committee  also  did not
try to agree  about the relative importance of  the various criteria
(human- health, ecology,  and economics)  employed.

     These early  attempts  at  priority-setting  illustrate  three
more general  problems that will  inevitably arise when any  group
tries to  set priorities  and allocate   resources  among  a  set of
problems this large  and  diverse.    The  first,  and by far the most
important, is that different problems are significant for different
reasons.  If problems differ  in degree  (i.e.,  severity) but not in
kind (i.e., the nature of their adverse impacts),  and ir reasonable
information exists on the severity of the problems, priority-setting
is relatively  straightforward.   If one substance is  predicted to
cause 1000 cancer cases  annually  and  another one  case,  deciding
                                IV-7

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which  is  more important is  not  difficult.   There is,  however,  no
non-controversial way to compare a pollutant that is present in air
and  causes  cancer  in  humans  with  one  that affects  only  fish.
Comparison of unlike objects  and  issues involves value  judgments
and  cannot be done purely on the basis of science.

     Previous and  concurrent  lEMPs  had not  directly .confronted
the  tradeoffs between health and ecological problems.  The Philade-
lphia  study  concentrated solely on  human health because  EPA felt
when it  initiated  the project that  it lacked the methodology and
the  resources to analyze both  health and ecological problems.  The
IEMP in  Santa Clara County,  California,  concentrated on  health
issues because of  a  widespread  consensus  that  those  issues were
most pressing.

     In Baltimore  the  consensus  was  the  opposite:  that  human
health was  not the  only concern that the  IEMP ought  to  address.
The  TAG in  Baltimore felt  thatv effects  of  pollution on ecosystems
and  the  ground-water resource also  deserved attention.   To  solve
the  problems  arising  from the  lack of  any non-controversial method
for  making tradeoffs  between health and other environmental problems,
the  TAG  developed and  applied  three separate  methodologies  for
evaluating the impacts caused by each of the potential issues:  one
for  human health, one for ecological damage,  and one for the resource
impact caused by ground-water  contamination.   The TAG did  not make
any  attempt to compare directly the impacts measured by each of the
three  methodologies.   Instead, it  used the  methodologies  to define
potential serious health,  ecological,  and  ground-water  problems,
and  agreed  to conduct  further research  on the  problems  in each
category that appeared to be the most severe.

     The choice of the three measures of  environmental degradation
human  health,  ecology, and resource impact—arose by consensus  of the
TAG.   The twin mandates to protect human health and the environment
(i.e., ecosystems) are widespread in both Federal and  state statutes.
More recently,  especially  in  the  light  of growing  concern  about
hazardous waste, enviromental  agencies have turned  their  attention
to impacts  caused by pollution  to  ground-water resources.   The
economic costs of  switching  to  alternative  sources  of  drinking
water  if ground-water should become contaminated has led to increased
governmental  attention  to  ground-water  protection.   On the  other
hand,  ground-water contamination has at  most an indirect  effect on
the health  of ecosystems.   The TAG  considered , including  a fourth
measure, the  costs and  monetary  impacts of pollution,  but'decided
to defer most considerations of  cost until  the second phase of the
project.  Thus,  the  criterion of  economic  impact  is  replaced  by
"impact to ground-water resources."

    The Management Committee  reviewed  and  approved the  decision
to include  the three impacts  proposed  by  the TAG.   The  decision
to examine other measures of environmental degradation in
                                IV-8

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to human health risk was  an important one: the inclusion of  these
other measures is one  of  the principal factors distinguishing  the
scope of the  Baltiore  IEMP from that of  the  first phase of  other
lEMPs.

     Once the three  measures were chosen,  the  TAG  chairman selected
TAG members  to  head each of  the three  subcommittees.   Each  TAG
member then  volunteered to serve on  at least one of the  subcom-
mittees.  Each subcommittee was charged with developing and applying
a methodology for ranking  the  issues  according to their  importance
against one of the primary criteria.

     Each of  the  subcommittees  then analyzed  only  those  issues
that it  felt to  be  relevant  to the  type  of   impact  under  its
examination.  These  included issues  for  which  they had to postulate
effects because they did not have actual data on  exposure or toxi-
city.  For example,  though  surface impoundments may affect  ground-
water and  ground-water  contamination may  ultimately  find  its  way
into the harbor,  no data were available on the timing or magnitude
of these effects.

     The human health  subcommittee  evaluated  about  two-thirds  of
the thirty-two issues.   The results  of these analyses  are described
in Chapter V.  Those not  evaluated were clearly  of primary  import-
ance to  the  aquatic life   of  the harbor.   The ecology and  ground-
water subcommittees   each   evaluated  about half  of   the   issues.

     Many of  the issues were analyzed by  more than one  subcommit-
tee.  For  instance,  chromium  in the harbor  was  examined  by  both
the ecology  and  ground-water  subcommittees.    Bioaccumulation  of
toxics in  fish  was  considered  by  both  the  human and  ecological
impact subcommittees* .  Septic  tanks were examined  by  both  the
human health  and  ground-water  subcommittees.   Metals was the only
issue studied by all three.

     The TAG  did not intend,  by  splitting  its analysis  into three
subcommittees, to deny  the  existence of  tradeoffs  among  various
environmental goals.  Its  intention,  instead,  was to defer  explicit
consideration of those tradeoffs until  it had developed more data
on individual issues and  had determined,  to  its  satisfaction,  the
relative importance   of  the  various   issues within each reference
category with regard to the appropriate measure.

     It also  felt .that  the value judgments necessary to determine
the relative  importance of these different types  of  environmental
impacts could be  made  at  a  later step.   Since the TAC's role  was
only advisory,  the   MC  should  ultimately make   these  decisions.,

     A second major  problem  in  priority-setting,  which 'the TAC's
early efforts also illustrate, is that the information available to
the committee  on each  problem  varies enormously in  reliability
and in  sheer bulk.   For example, emissions from  power plants have
                                IV-9

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been exhaustively  studied.   On the other hand,  much less informa-
tion is  available  on discharges  to  ground-water  that may  occur
from surface impoundments.  Similarly, the carcinogenicity of
benzene has been confirmed by numerous  epidemiological and laboratory
studies, while virtually no information is available on the toxicity
of titanium tetrachloride.  Clearly the degree of certainty about a
problem should be  factored into the prioritysetting progress,  but a
great deal  of  honest  'disagreement exists  about how to  take that
uncertainty into account.

All three  of the  TAC's  methodologies included  appraisals of  the
degree of  certainty associated with  the analysis  of each problem.
These appraisals were qualitative and based on the best judgment of
the committee members.  They were not  incorporated into the analysis
in any  quantitative way.  To  do so  (for instance,  by  multiplying
quantitative estimates  to  damage  by a  numerical  surrogate  for
certainty) would have itself assumed a  degree  of  certainty  which
does not in fact exist.

     The third major problem in,priority-setting is that the pollu-
tant-specific,  source-specific, and medium- or exposure route-specific
problems are bound to overlap  somewhat.   For example, power plants
(listed as a source-specific problem) contribute both to acid rain
(a pollutant-specific  problem)  and water discharges  to the harbor
(a medium-specific  problem).  This  sort  of  overlap is inevitable,-
-indeed, it  is  at the heart of  the IEMP approach—  but,  it makes
priority-setting difficult  because the  severity  of a  particular
problem can depend  on how it is defined.

     To address this  problem;  the TAG and  EPA  separately analyzed
each of the thirty-two  issues,   ignoring  overlaps  existing  among
them.  Through the use of a common metric (such as cancer risk) for
issues in a reference category, the severity of a pollutant specific
problem (e.g.,  benzene)  could  be compared directly against that of
a source-specific  problem  (e.g.,  sewage  treatment plants),  even if
some overlap exists.   Similarly,  comparing ambient  levels  against
one another, as  the ecological impact subcommittee did, implicitly
includes the cumulative  effects   of all  sources.  Clearly,  if the
results of the study were used to estimate the overall magnitude of
environmental problems  (measured  in  terms  of  human  health,  or
ecological damage,  or  ground-water  impact),  the numerical measures
of severity  could  not simply  be  combined,  but  would  have  to be
corrected to account for the overlap among problems.

     The TAG chairman  directed each of the subcommittee (chairmen)
to recommend issues for further  analysis  in the  project's  second
phase.   The human health  subcommittee was  asked to recommend up to
five issues and each of the other subcommittees was asked to recom-
mend up to three.   In other  words,  the TAG  intended to  use the
subcommittees to reduce  the number of possible  study  topics form
thirty-two to  eleven, to  apply  the  'secondary  criteria to  those
                               IV-10

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eleven topics, and then reduce the list further  in full  meetings  of
the TAG.  Once this method of priority setting was agreed upon,  the
TAG and its subcommittees worked with^considerable speed.  Develop-
ment of the methodologies described below took about six weeks  and
the application of  the  methods  to the  ranking of  the  32  issues
another month.

     The first  and  second  steps  worked  as planned:   the  health
subcommittee recommended five issues,  the ecological impact subcom-
mittee three, and  the ground-water subcommittee  two.   One topic—
trihalomethanes in drinking  water—was eliminated  because  it  did
not meet one  of the secondary criteria.  The last  step turned  out
to be unnecessary because  of overlap  among  the  study topics  recom-
mended by the various groups (See Chapter VIII.).

RANKING OF ISSUES AGAINST THE PRIMARY CRITERIA

     In assessing the  impact of  each  of the thirty-two potential
problems on  human health  in  the  Baltimore area,  the  TAG  used
standard quantitativerisk  assessment  models which  were developed
by EPA  and  which  have been  used  in other  lEMPs.   The  models  have
been used expensively in a number of other  applications,  as well,
such as  in  the development  of  regulatory standards.   They  are
currently the  subject of  a  scientific peer review.    We  discuss
them fully  in  Appendix  A  of  this  report and  describe  their
application in the Baltimore IEMP in Chapter V.

     The models are  conceptually  simple.  Ambient  monitoring  data
or, where these do  not  exist, estimated ambient  levels  based  upon
source emission estimates,  are used  in conjunction with exposure
factors to  estimate  human exposure to each  substance under  study.
These estimates of  exposure  in  turn  are  combined  with toxicolo-
gical estimates  of  potency  to  yield quantitative  estimates  of
individual risk.  These  are  expressed as  the  incremental  proba-
bility of disease  incidence (not death) that would conservatively
be expected to  result from  that  exposure.   Combined with  data  on
population densities, the information  on  individual  risk  can  be
extrapolated to yield numerical estimates of disease  incidence in
the population attributable to exposures to each pollutant.

     The models are deliberately  designed  to  yield  conservative
estimates (i.e.,  to  be   protective  of public  health)   both  of
individual risk  and  of   aggregate disease  incidence   to  average
ambient values  for  the pollutant  in question over  long periods  of
constant exposure.   Their primary  usefulness   is  thus   in  setting
priorities and  allocating  resources  rather  than  in  predicting
absolute risk.   For each of the pollutants analyzed, the methodol-
ogy is much more likely to overstate risk than to understate it.


     However, the  models  do not  take  into account  intermittent
peak levels  of  pollutants to  which an  individual may  be exposed
during his  or her  daily  activities and which,  through  dilution in
                               IV-11

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the ambient  air,  are not well represented by ambient average daily
concentrations.   [EPA's Total Exposure Assessment Methodology (TEAM)
projects attempt  to  identify these exposures through what they term
"personal" monitoring. We describe this method in greater detail in
Chapter IX.]   Where these  are expected  to  occur  frequently,  the
models may be of  limited use.

     The human  health  subcommittee  chose  aggregate expected  in-
creases in disease  incidence as the primary criterion  for  setting
priorities among  potential  health  problems.   In  addition,  EPA
calculated for  the  subcommittee's consideration  risks  incurred by
individuals  at  sites of. the highest monitored  values  for specific
pollutants.  While  maximum  individual  risks can  be important, the
subcommittee felt  that aggregate  disease incidence  was a  better
.criterion for general  priority-setting  since  it takes  into account
the numbers  of  people potentially  affected  by  each environmental
problem.

     The methodology ignores the possible synergistic or antagonistic
effects of simultaneous  exposure  to  more than one pollutant.   With
few exceptions,  scientific  understanding of those  interactions is
so limited that we cannot state with any confidence how much, if at
all, risks  from those  simultaneous  exposures might vary from the
sum of the individual  risks.   The toxicological  scores  used  by EPA
in general  and  the  IEMP  in particular are all substance-specific
and do not take into account any possible interactions among pollu-
tants.

     The TAG  applied  its  qualitative  estimates  of certainty and
strength of  evidence to  each problem analyzed from the perspective
of human health.  The committee characterized the information which
included source  characteristics  (identity of the  sources,  release
rates, and durations), ambient levels,  and dose-response  functions,
as being "good,"  "fair," "poor," or "unknown."

     The TAG  did not  consider  epidemiological  data   specific to
Baltimore in  its  appraisal  of  human  health   risks.    The  human
health risk  analysis overseen  by the subcommittee  was  an exercise
in prospective risk assessment that attempted to estimate the risks
of contracting  diseases  in  the future  which  are  attributable to
current exposures.  By contrast, epidemiological studies  show  (when
they are  successful)  the  results  of  past  exposures,  the  health
effects of which  may lag the  actual  exposures by  many years-.  (A
hazard evaluation of a chemical does, of course, consider epidemio-
logical studies  as  the basis  for  judgments  about  its  toxicity.)
The health  subcommittee  recommended five  issues to the  full TAG:
trihalomethanes in  drinking water,  toxic  air  pollution, benzene,
metals in air, and  indoor pollution.   More detailed information on
their methodology  and   deliberations  is   provided   in  Chapter  V.
                               IV-12

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     To measure  e co1og ica1 damage,  the TAG,  nor anyone  else  for
that matter,  did not  have  well-developed and  widely used  models
of the  sort  that have been available  for  assessing human  health
risk.  The TAG  subcommittee  charged  with  developing methods  for
ecological effects relied on  surrogate measures for  damage  to  the
Baltimore Harbor and the Chesapeake  Bay.   EPA  examined monitoring
data on sediments  and  the  ambient water,  and compared those  data
to the  Water  Quality  Criteria  (ambient  standards   set  by  the
Agency's Office  of Water).    By  constructing  simple  ratios   of
measured concentrations  to  allowable concentrations,  the TAG
subcommittee compared  various  pollutants.   Ratios  of greater  than
one were  considered  to  be indicators  of  possible  problems.   As
with the  human  health  analyses,  the  subcommittee  characterized
their confidence  in  the  underlying  data  through  the  use  of  a
qualitative ranking system.

     Though this comparison of ratios  does not yield actual
estimates of ecological damage, it  does serve the purposes  of  the
screening analysis.  It  provides  a  means  for  ordinally  ranking
specific pollutants.   Furthermore,  since  the  EPA  standards  take
into account the  most  recent  findings  on  the  levels  at  which
pollutants begin affecting  aquatic  life (i.e., ecological
thresholds above which ecological  damage increases with  pollutant
level), the  ratios  allow a  rough  estimation  of  the magnitude  of
the effects.

     The method  does  however  ignore  (as  does the  human  health
methodology)  possible  synergistic  effects of exposure of  biota to
more than one pollutant.   Little is known about such effects,  and
the data  that   would  be  necessary   to   construct  more  realistic
dose-response curves do not exist.

     Besides not measuring actual  ecological  damage,  the  method
does not provide a way .to  compare  ecological damage  to  the human
health risks discussed  above.   The  extent  of actual  ecological
damage attributable to pollution in the Harbor is not well
understood, and  the  relative  importance  of  that  damage  compared
to human health effects resulting  from  other  forms of  pollution
is a . matter  of  values.    These  issues  were  discussed  in  the
meetings of the TAG and  decided,  implicitly  or explicitly,  in the
committee's decisions   about  resource  allocation  and  priorities
(budgeting).

     The ecological  impact  subcommittee  applied   its  methodology
only to  water   pollution problems.    Effects  of  air pollution  on
ecosystems are  attributable  primarily to  conventional pollutants,
which had  previously  been  excluded  from the  study  (see above).
No ecological  standards  exist  with  which  to compare the limited
ambient data on 'air  toxics.    Hazardous  waste  was  considered  in
the ecological  study to  the extent that  it affects  surface water,
but the  TAG  subcommittee did not  attempt  to  isolate the effects
of hazardous waste on  ecosystems   because  it  felt that  the data
were inadequate  for  this   purpose.    Nor did  it  examine  ground
water from an ecological

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    . The ecological  impact  subcommittee  recommended  to  the  full
TAG that  toxic metals  in ambient  water,  previously  contaminated
sediments as a source of water  contamination,  and  bioaccumulation
of toxics  in  aquatic  organisms  be  studied  further in Phase  Two.
A full  discussion of the  ecological methodology and  its  applica-
tion is in Chapter VI.

     Finally,  the  ground-water  resource  subcommittee developed  a
methodology for evaluating the impact on ground-water resources
which are  caused  by  releases  from  various  categories of  sources
(e.g., landfills,  surface  impoundments,  and  underground  storage
tanks).  The   subcommittee  agreed  on  a  list  of  criteria  which
included considerations  of  both physical  and  economic  impacts.
Included as  evaluative criteria  for physical  impact  were  source
characteristics (e.g., number of facilities in each source
category), release  volume,   concentration  of  contaminants  in  the
potential releases, environmental persistence  of  the contaminants,
likelihood of  contamination, and potential extent of damage.
Economic considerations included the likely costs both of prevention
and of response.  Each criterion was weighted equally.

     The subcommittee  members  then  ranked  each  source  category
against each criterion  on a scale  of 1 (not severe or high)  to 5
(very severe  or  high).   Thus,  for  example,  underground  storage
tanks could receive a rating of 5 against the "source characterist-
ics" criterion because there are numerous underground storage tanks
in the area and because potential release volumes are large.   After
each subcommittee  member  had individually  evaluated  the  source
categories, the subcommittee met  to  reach a consensus on the import-
ance of  each  source  category  against  each  criterion.  Through  a
series of meetings, the subcommittee was able to develop a consensus
on the source  categories which appeared to be most urgently in need
of further study.

     The ground-water subcommittee recommended to the full TAG that
pollution of ground-water by metals  and pollution from underground
storage tanks be studied further  in  the  second phase of the project.
The subcommittee decided  not to  recommend a third  issue  for Phase
II study because  it  felt that the  two problems it did  recommend
were significantly more important than  all  the others.  A detailed
discussion of  the  ground-water  methodology  and  its  application
appears in Chapter VII.

     In summary, ten issues, which  we list  in  Figure IV-3,' emerged
from the priority  setting process.   In  the  next three  chapters,  we
explain in greater detail how each priority-setting approach worked
and describe the  results of  the analyses that  were  conducted  in
support of these approach.  The application of the  secondary criteria
to those issues, and the work subsequently done to analyze them,  is
discussed in Chapter VIII.
                               IV-14

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                            Figure IV-3
          Study Topics Recommended by the TAG Methodology
        Subcommittees after the first Priority-Setting Round
Human Health Risk Subcommittee

Benzene
Trihalomethanes in drinking water
Multi-media metals
Toxic air pollution (low molecular weight organics)
Indoor air pollution
Ecological Impact Subcommittee

Metals
Sediments
Bioaccumulation of toxics in aquatic organisms
Ground-Water Resource Damage Subcommittee

Metals in ground water
Underground storage tanks
                               IV-15
                                                       	' "Hi1 iui""ii" 'fi" ffll

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          CHAPTER V




ANALYSIS OF HUMAN HEALTH RISKS

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                 V.  ANALYSIS  OF HUMAN HEALTH  RISKS


     Using the  priority-setting exercise  discussed  in  the pre-
vious chapter, the Technical Advisory Committee (TAG)  sorted  through
32 issues to select a subset of topics warranting  further analysis
in Phase II.   The topics were organized into one of  three categories
(human health, ecological damage,  and resource damage),  and three
subcommittees were  established  to review  and recommend  candidate
issues in each of these areas.  This chapter summarizes the analyti-
cal findings for the four  issues that the Human Health Subcommittee
identified for  further  analysis   in Phase  II:   organics   in  the
ambient air  (including  benzene);   metals  in the  ambient air  and
lead.in the general  environment  (especially lead in dust and  water);
indoor air; and trihalomethanes in drinking water.

     We present  the  results   in  this   chapter  in  terms  of  the
risks to  human health posed  by each  environmental   issue.    While
the risk  assessment models  are  fairly  straightforward,  there  are
numerous limitations  that must be  considered  when  interpreting
the results  generated  by these techniques.   For that  reason,  the
first section  of  this  chapter presents  a brief overview of EPA's
standard methodology  for  assessing  risks  to  human  health  and
discusses the  major limitations associated with quantitative risk
assessment.  A  more thorough  discussion  of how  we   approach risk
assessment and its limitations appears in Appendix A.

     The second  section   of  this   chapter  summarizes  our findings
on the  risks  to  human health  associated with each  of the four
issues the  Human Health  Subcommittee  selected.   It is important
to note that the results presented are not based on exhaustive eva-
luations of each topic.  The analyses performed in Phase I were de-
signed primarily to provide the members of the Human Health  Subcomm-
ittee with sufficient information on the relative significance of
different environmental issues.  Subcommittee members would  use this
information to select topics warranting further investigation and
to set priorities for additional work in Phase II of the  IEMP.

     The third section provides a comparison of risks across  pollu-
tants and routes of exposure.  This chapter also provides a  discus-
sion of  the  conclusions  that  can be drawn  from  our  analyses of
human health  risks  in Baltimore  and  the  implications that  our
findings may have for Phase II.

RISK ASSESSMENT AND ITS LIMITATIONS;  AN OVERVIEW

     Using standard EPA methods and models, Phase I of  the Baltimore
IEMP assessed  the  human health   risk   attributable  to different
sources, pollutants, and exposure pathways in order  to  set research
and management priorities for selected issues.
                                V-l

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The purpose  of  this  section  is  to  provide  the  reader  with  a
brief overview  of risk  assessment  and  its limitations.   A  more
detailed discussion  of risk  assessment can  be  found in Appendix A.

Defining Risk Assessment

     Risk assessment  is  a technique that  allows  one  to  estimate
what health  effects   may  result  from current and future' environ
mental exposures.   While  there   is   some  controversy  surrounding
EPA's risk assessment techniques, it is important to evaluate these
procedures in light of their  main objectives: to permit a comparison
of one risk  with another and to  give a  very general sense  of the
risk a  substance  may present,   rather  than to  make a definitive
statement concerning  the absolute risk posed by a  particular  sub-
stance, pollution  source, or exposure pathway.

     It is  important  to  understand  that  risk  assessment  does
not examine  disease   incidence  in  the local  population  and  then
attempt to  link it  with environmental exposures.   Because it  is
not an  epidemic logical  study,   the  IEMP  risk  assessment is  not
intended to and does not  answer questions  such as what  caused a
statistically higher  rate  of cancer in  one  neighborhood  or  part
of the community.

Generating Risk Estimates

     In the  IEMP, we define  risk  to an  individual  as   the in-
creased probability that an individual constantly exposed to one or
more chemicals  will  experience  a particular adverse  health effect
during the  course of his or  her  lifetime (the  average  lifetime
is assumed  to  be  70  years).   The  IEMP  risk  assessment  combines
estimates of  toxicological  potency   (derived  from laboratory and
occupation studies) with estimates or measurements of local contami-
nation (exposure)  to calculate  risks to  the local  population.  We
discuss the basic techniques for estimating toxicological potency and
exposure below.  We then present how these data are-used to develop
several different  measures of risk in the Baltimore IEMP:

     o  Aggregate  excess  cancer  incidence,  i.e.,  risk  to  the
        population

     o  Lifetime risks to the most exposed  individual (MEI)

     o  Lifetime  risks  to  the  average  exposed  individual '  (AEI)

     o  Increased  risk of noncancer health  effects.
                                V-2
                                                              P'l"

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     Estimating Toxicological Potency

     Cancer.  Assessing the  toxicological  potency for  carcinogens
involves:  (1) a  qualitative "hazard identification',' to  determine
where there is  evidence  that a  chemical  causes an  adverse  health
effect and, if so, (2) a quantitative estimate of the "doseresponse
relationship"  or potency of the chemical.   The carcinogenic assess-
ment methodology  we   employ  in  the  Baltimore  IEMP  is  consistent
with EPA* s Guidelines  for Carcinogenic Risk Assessment, as published
in the Federal Register,  September 24,  1984.

     The qualitative hazard evaluation, which  is  based  on a  review
of human epidemiological studies and animal experiments, determines
the strength of the evidence that a substance is carcinogenic.  EPA
has developed a scheme to stratify the weight of evidence into five
groupings:  Group A:   Human Carcinogen;  Group B:   Probable Human
Carcinogen; Group C:   Possible Carcinogen; Group D:  Not Classified;
and Group E:  No  Evidence  of Carcinogenicity for Humans.   Appendix
A discusses the groups in more detail.

     If there  is  sufficient qualitative  evidence to suggest that
a substance is a suspected carcinogen,  a quantitative dose-response
relationship,  or unit  risk  factor,  is  developed.   EPA's Carcinogen
Assessment Group (CAG) develops potency estimates using a number of
simplifying assumptions,   which  include:    (1)  interpretation  of
laboratory or  animal  data;  (2)  extrapolation ,pf  data  to  other
species or  populations;  (3) extrapolation  from data on  high-dose
effects to  low-dose  exposure   situations  representative  of  most
environmental conditions (EPA assumes that cancer is a nonthreshold
health effect); and  (4)  estimates  of the  effects  of  exposure to
toxic chemicals.

     The greatest area of  uncertainty surrounds  the mathematical
models used to  extrapolate from high animal  or human occupational
exposures to  low  environmental  exposures.   In estimating potency
from animal studies, CAG uses the most sensitive species observed
and calculates the upper (95 percent) confidence limit on the
estimated low-dose range of the dose-response relationship curve.
We emphasize that use of the upper-bound potency estimate does not
necessarily give a realistic prediction of actual risks to humans.
The true value of the risk is uncertain, and for many substances
the lower-bound estimate is zero.

     Noncancer.  The  noncancer  health  effects . that  we  examine in
the Baltimore  IEMP  included 'systemic  effects,  such as  liver and
kidney toxicity,  fetal developmental effects,  and  neurobehavioral
effects.  The  crucial distinction  between quantifying  cancer and
noncancer effects is  the assumption that  cancer can occur  at any
environmental exposure, i.e., there is no threshold  for the  effect.
                                V-3

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For most  other environmentally  caused health  effects,  we  assume
that thresholds exist.  Therefore, the  first  step in the quantita-
tive evaluation of  a  noncancer  effect is calculating the threshold
below, which no effects are expected,  i.e., the no-effect threshold.

     We rely on EPA Reference Doses (RfDs) and on thresholds computed
by Regulatory  Integration Division (RID)  toxicologists  and consul-
tants to  determine the threshold dose  below, which  no  observable
adverse effects are assumed  to  occur.  The thresholds developed by
RID employ the  same procedures  used  in estimating  RfDs.   We refer
the reader to Appendix A for a more comprehensive discussion of the
analytical approach for developing no-effect thresholds.

     Estimating Exposure

     To calculate exposure,  we need to know the concentrations of a
chemical in the medium of concern (either ambient or indoor air or
drinking water).  As part of this calculation, we also make assump-
tions about  how  ambient  concentrations  relate  to  actual  human
exposures, or dose.  We discuss each separately.

Ambient and Indoor Levels.  We can estimate  ambient concentrations
in twoways:directmonitoring or  simulation,   i.e.,  predictive
transport and fate  modeling.  In Phase  I  of  the  Baltimore IEMP, we
relied heavily  on  monitoring data  to  calculate  risks  to  human
health.  We decided primarily to use ambient data   because  of the
uncertainties in the available  source and pollutant release inven-
tories required for modeling.  We did, however, use data on sources
and pollutant emissions for  estimating  the contribution to ambient
concentrations from sewage treatment plants because of our experience
with such  facilities  in  the Philadelphia  IEMP.    For   indoor  air
risks,  we have  made  inferences  on  likely exposures in Baltimore
based on monitoring data from other cities.

     While ambient  monitoring  data  often provide the  most direct
measure of environmental conditions,  there are two important limi-
tations to their usage:

     o  Monitoring  data  are  often  taken  from  a  few  specific
        points and  must  be  extrapolated  over  the  area  of  con-
        cern.  In  contrast,  modeling  can take  into account  geo-
        graphic variability  and  can  pinpoint  the  sites of  max-
        imum ambient  concentrations.   The  latter  is  especially
        important in our  assessment   of  lifetime  risks  to the MEI
        and the increased risk of noncancer effects.

     o  Monitoring  data,  without extensive  source  modeling,  can-
        not link observed ambient concentrations  to sources, which
        which is essential  for  making  risk  management  decisions.
                                V-4

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     While Phase II of  the  Baltimore  IEMP will focus on  gathering
     the data needed to  identify  sources,  our reliance on  ambient
     data in Phase I precluded us  from quantitatively, assessing the
     contribution of specific sources,.

     Exposure Constants.  Once we have calculated ambient  levels,
we need to relate these to actual human exposures.  EPA uses  stan-
dard assumptions,  called exposure  constants,  to  account for  the
for the amount of  air  or water a  typical  person takes in  each day,
and the weight  of  an  average person.   Specifically, EPA  assumes
that an average  person  weighs  70  kilograms,  breathes  20  cubic
meters of air and drinks two liters  of water each day.

     Risk Measures

   •  Aggregate Annual Cancer Incidence.  The  aggregate population
risk is the total estimated increase in cancer incidence  (number of
cases), above  background levels,  in  an  exposed  population.   We
calculate incidence by  first establishing exposure  (i.e.,  ambient
levels multiplied by the exposure  constants).  We then multiply the
estimated exposure levels by  the  exposed  population  and the appro-
priate potency  factor.    Finally,  we divide  by  70,  the  assumed
average lifetime, to generate annual incidence estimates.
Exposure  =
                                amount of air
concentration in  air or  water  x  inhaled  or  water
                                consumed per day
Increased lifetime =
risk to the
population

Aggregate annual   =
cancer incidence
        Exposure x unit potency  x
estimated exposed
population
        Increased lifetime risk to the
        population
     -  70 years
     Lifetime Risks to the Most Exposed Individual (MEI)  We
define risks  to  the MEI  as  the  increased probability  that  an
individual constantly exposed  to  the  greatest  amount  of  one  or
more chemicals  over  a  lifetime  (70 years)  will  contract  cancer.
Generally, this  calculation  is  computed  by  simply  multiplying
the maximum  ambient   concentration by  the  exposure  constant  and
the appropriate unit risk factor.
Lifetime cancer risk
to the most exposed
individual  (MEI)
           = Continuous 70 year exposure
             at highest average annual
             concentration
       x unit
         potency
                                V-5

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     In the  Baltimore  IEMP,  we  could  not  use  the  techniques
traditionally employed  by  EPA  to  quantify  maximum  ambient  air
concentrations because  of  data  limitations.   EPA generally  uses
dispersion modeling  to locate the point of  maximum ambient  con-
centration.  In  the Baltimore  IEMP, we  based  our  risk  calcula-
tions on  ambient  air  quality data and  were,   therefore,  limited
in our  ability  to  predict  the  maximum  ambient  concentration.
For our  purposes,  we  defined  the  "maximum"   ambient  pollutant
level as  the  highest  average   measured  value  reported  for  the
pollutant at any of the monitoring sites.

     Lifetime Risks to the Average Exposed Individual*   We define
risk to an average individual  as the increased  probability that an
individual exposed to the average amount of a chemical over a life-
time will contract  cancer.   We calculate the lifetime  risks to the
AEI by  simply  multiplying  the average  ambient  pollutant  level  by
the exposure constant and the appropriate unit risk factor.


     Increased Risk of Noncancer Health Effects.  We determine  the
increased riskofnoncancer healtheffects bycomparing pollutant
concentration levels  with  estimated no-effect  human  thresholds.
Because a single  substance may have many different  thresholds  for
the different health  effects associated with  it,  we  examine each
health effect for  each , substance  separately.   If  exposures exceed
the no-effect threshold,  we then  indicate  the  possibility  of  in-
creased risk of that effect.  We also attempt to identify the popu-
lation exposed to such concentrations.

Limitations

     Although we  have  already   highlighted  some  of  the  limita-,
tions of  risk  assessment,  it   is  important  to  summarize  these
points below  to  ensure  that  the  reader  properly  interprets  the
estimates of risk presented in this chapter.

     o  The  estimates  of  individual health  risk  and  aggregate
        incidence from  exposure   to  toxics  should  not be  inter-
        preted as  precise  or absolute  estimates of  future health
        effects.   The  simplifying  assumptions  and  uncertainties
        in both the toxicology and exposure components  are simply
        too great  to  justify  a  high  level  of  confidence  in  the
        precision of the  results.  They are approximations  of the
        potential risks to  human  health  and  are designed to permit
        comparison across different  sources, pollutants,  and expo-
        sure pathways.

     o  The  potency and  threshold  estimates  used  in this  study
        are consistently  conservative (i.e.,  upper-bound)  in  the
        direction of overestimating risk for the particular pollut-
        ants and exposure pathways we have assessed.
                                V-6

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     o  We may  understate risks  to the  extent  that  we  have  not
        considered all pollutants, sources, and exposure .pathways.

     o  The  results  from  a  risk  assessment are  based primarily
        on existing knowledge..  As new  scientific data and  tech-.
        iques become available, these results  may change.

ORGANICS IN THE AMBIENT AIR

     On the  basis of  the  scoping exercise  described below,  the
Human Health  Subcommittee selected  organics  in the  ambient  air,
including benzene, as a topic deserving more attention. To perform
this analysis,  RID staff  and technical  contractors  gathered  all
available information on a variety of toxic organic compounds known
or believed to be present in the Baltimore area and used these data
to conduct a preliminary exposure and risk assessment.  This section
documents the  data used in  this analysis  (pollutants,   sources,
ambient levels,  exposed populations,  and unit risk factors),  our
results, and the limitations of the analysis.

     We should  note  that  our  discussion of limitations   in  this
section, and  in the  others  to follow,  focuses  solely on limita-
tions in  the scope and in  the  exposure data used in the analy-
sis.  The  limitations  of  the  toxicological  data  are  presented
in the  previous section  and  are applicable to   all  quantitative
risk assessments.

Pollutants

     For the  purposes  of  our  preliminary analysis  of  volatile
organic compounds  (VOC)  in  the ambient  air,  we  were limited to
an investigation "of  those pollutants  for which  we  either already
had data  or  that  we  could  easily   characterize  using  existing
information.  We  gathered information  on organics  in the ambient
air during  Phase  I  in  two  ways:   (1)  sampling  and  analyzing
ambient air  and   (2)  collecting  and  developing,  where  needed,
estimates of  toxic  emissions  from  facilities    situated  in  the
Baltimore study  area.   Because  of the  substantial  uncertainty in
our emissions estimates,  as  well  as  the limited  source  coverage,
we decided  to base  our  risk calculations solely  on  the ambient
monitoring data.

     The VOC  monitoring program successfully sampled  for  and  ana-
lyzed the following target pollutants,  which  were  the focus of the
Phase I  exposure and  risk assessment  (Phase  II  will encompass a
wider range of pollutants):^
                                V-7

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     o  Benzene

     o  Carbon tetrachloride

     o  Chloroform

     o  Ethyl benzene

     o  Xylene

     o  Toluene

     o  1,2-Dichloroethane

     o  1,2-Dichloropropane

     o  Trichloroethylene

     o  Perchloroethylene

The sampling  program  focused  on  these  pollutants  based  on  a
preliminary data  review  of  sources  in  the  area,  as  well  as
the ubiquity  of  some of these  substances,  such  as xylene  and
toluene in  urban  ambient  air.   The  sampling  program  and  its
results are  discussed  in  more  detail  later  in  this  chapter.

Sources

     Baltimore's industrial base  is  very  diverse,  including  such
sectors as  iron  and steel production,  electronics,  pesticide  for-
mulation, shipbuilding, and petroleum marketing.   The major
Baltimore source  categories  emitting  the  ten pollutants  consid-
ered in  our analysis  are listed in  Table V-l.  Phase II will  be
directed toward  characterizing  better the  sources of  organics  in
the ambient air and their release rates.

     Of the industries listed in Table V-l,  many  are well-documen-
ted sources of  these pollutants.   An important  exception  to  this
traditional array of  source categories  is  volatilization from sew-
age treatment plants.  Because  of  EPA's  work  in the Philadelphia
IEMP, our  attention  was   initially directed  towards  Baltimore's
two municipal  sewage  treatment  plants  that  receive  industrial
wastewater (Patapsco  and  Back  River).   In  Philadelphia,  EPA's
analysis indicated that the city's largest industrial sewage treat-
ment plant was also an important source of VOC emissions.

     We developed  preliminary  estimates  of  air  emissions  from
the Patapsco  and Back  River  sewage  treatment  plants  (including
both volatilization  and   sewage  sludge  incineration  at  Patapsco)
using data collected by Black and Veatch in 1984^ and a simple mass
                                V-8

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                                          Table V-l

                       BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS

            MAJOR SOURCES EMITTING SELECTED ORGANIC COMPOUNDS IN THE BALTIMORE AREA
      Pollutant

Benzene




Carbon Tetrachloride

Chloroform

Ethyl Benzene


Xylene



Toluene



1,2-0ichloroethane

1,2-Oichloropropane

Trichloroethylene



Perchloroethylene
                                Sources

Bulk petroleum terninals;  chemical manufacturing; sewage  treatment plant
volatilization; agricultural chemical production; iron and ateel produc-
tion; utilities; municipal incineration; electronics; metal can fabrica-
tion; road vehicles;  boilers;-and service stations  (gas marketing)

Sewage treatment plant volatilization and chemical  productions

Chemical production;  cooling apice manufacturing

Utilities; gas narketing;  road vehicles, solvent surface  coating; and
solvent printing and graphing

Bulk petroleum terminals;  chemical manufacturing; pesticide  formulation;
shipbuilding; can production;  phone  manufacturing;  road vehicles; car
body manufacturing; and service stations  (gas marketing)

Sewage treatment plant volatilization;' shipbuilding; bulk petroleum
terminals; commercial printing; can  production; car body  manufacturing;
phone manufacturing; and aervice stations (gas marketing)
                   a
Gas marketing; paint manufacturing

No reported sources

Sewage treatment plant volatilization; phone manufacturing;  cooking
equipment production; electroplating; and areawide industrial solvent
usage

Sewage treatment plant volatilization; can production; glass container
fabrication;  and dry cleaning
Source:  Baltimore  IEMP  database compiled by RID.

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balance algorithm.   The algorithm  assumes that  the  amount  of  a
compound that  volatilizes  is the  difference  between  its  influent
and effluent loadings, minus the removal efficiency of the volatile
compound.  Table  V-2 presents  our  rough  calculation of  volatile
organic emissions from the  two  industrial  sewage  treatment plants.

     Benzene accounted  for  nearly 94  percent  of  the  total  air
emissions we  estimated  for  the  pollutants   of   concern  at  the
Patapsco plant.   At  the  Back  River treatment  facility,  benzene
and methylene  chloride emissions  combined accounted for  roughly
85 percent of the total releases  of those  toxic pollutants considered.
An additional 10  percent of the estimated emissions  at  Back  River
were attributable to chloroform.

Ambient Air Levels

     From November  1983  to  February  1984, RID  supported  a  three
month ambient  monitoring  program  for  volatile  organic  compounds
in the  Baltimore  metropolitan  area.  EPA  collected  24-hour  inte-
grated air quality  samples  from ten  monitoring  sites every  three
days.  EPA  also  constructed two  meterological  wind stations  to
obtain data  on  wind  direction  and  speed  and  vertical dispersion.
Figure V-l shows the locations of the monitoring  sites.

     The air  quality  samples   were  collected  on  Tenax  GC  at  a
flow rate  of  about  20 milliliters  per  minute.   Forty  percent
of the  samples  were analyzed by gas  chromatography/mass spectros-
copy (GC/MS).   The  remaining  samples   were   analyzed  using  gas
chromatography with  a  Hall detector   for  chlorinated  compounds,
and a photoionization detector for aromatics.^

     The results  from the   monitoring  program are   summarized  in
'fable V-3.   The highest observed  concentrations  were  for xylene,
benzene, toluene,  and ethyl benzene.   It is  also  interesting  to
note the variation  in the  concentrations  of some  pollutants across
the monitoring sites.  Such variation indicates that exposures, and
thus risks,  to these compounds are not uniform throughout the study
area.  This is an important  factor  to consider during the Phase II
analyses to identify strategies for control.

Exposed Population

     As mentioned in  our discussion of  risk assessment,  the number
of people exposed to  ambient pollutant  levels  is a necessary'input
to the calculation of excess aggregate cancer incidence.  Similarly,
in considering risks  to the MEI,   one  must  weigh  the  calculated
individual risks against the number of  people exposed at  the site
of maximum ambient concentration.
                                V-9

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                    Table V-2
                               /"
BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS

    ESTIMATED EMISSIONS OF VOLATILE ORGANICS
   AND METALS FROM THE PATAPSCO AND BACK RIVER
             SEWAGE TREATMENT PLANTS

                               Patapsco Sewage
                               Treatment Plant
         Pollutant

  Benzene
  Chloroform
  1,2-Oichloroethane
  T r ichloroethylene
  Perchloroethylene
  Methylene Chloride
  Chromium  (VI)
  Nickel
  Cadmium2
  Copper
  Zinc
  Mercury
  Lead2

   Total
          Pollutant

  Benzene
  Chloroform
  Carbon Tetrachloride
  Methylene Chloride
  Perchloroethylene
  1,2-Dichloroethane3
  Trichloroethylene'

    Total
   Emissions
   (kkq/year)1
      45.3

Back River Sewage
Treatment Plant

    Emissions
   (kkg/year)1
      27. A
^Emission estimates have been rounded to one sig-
 nificant decimal; totals may not sum because of
 rounding,  kkg = 1,000 kilograms.
^Emission estimates for cadmium and lead are .009
 kkg/year and .02 kkg/year, respectively.
^Emission estimates for 1,2-dichloroethane and
 trichloroethylene are <.001 kkg/year.

Source:  Regulatory Integration Division, U.S. EPA,
         Issue Paper;  Publicly Owned Sewage
         Treatment Facilities.

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     FIGURE  V-l  LOCATIONS OF  AIR  QUALITY MONITORING
                   SITES FOR THE BALTIMORE IEMP
   BALTIMORH
  AND VICINITY
 KFf:

 AI* 
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Table V-3
BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS
AVERAGE MEASURED AMBIENT CONCENTRATIONS : ORCANICS IN THE AMBIENT AIR1
(micrograns per cubic meter-ug/ra')
Average

Compound 1 2 34 5
Benzene 12.0 9.5 10.2 12.9 12.6
Carbon Tetrachloride 1.1 0.9 0.6 1.3 0.9
Xylene 30.4 21. i 20.8 20.1 13.7
1,2-Oichloroe.thane ' 0.2 0.2 0.3 0.5 0.4
1,2-Oichloropropane 0.3 0.2 0.2 0.7 0.3
Trichloroethylene 0.9 0.5 0.5 3.9 1.4
Perchloroethylene 4.8 5.4 7.0 6.0 9.3
Site
1 Guilford
2 Northeast Police Headquarters
3 Southwest Police Headquarters
4 Holabird Elementary
5 Dundalk
6 Cheaapeake Terrace Elementary
7 Sun & Chesapeake
8 Ft. McHenry
9 U.S. Coast Guard Yard
10 Riviera Beach
^Concentrations are simple arithmetic averages.
Source: Versar, Inc., Draft Data Report for Monitoring

1111
5.5 12.1 10.6 7.8
0.9 1.2 1.4 0.7
5.7 17.2 16.4 13.6
2.6 0.7 0.2 1.0
0.1 2.0 0.4 0.4
0.4 1.1 1.0 0.2
1.5 3.2 3.9 2.9












Across
10 Sites
10.3 10.4
0*6 1.0
6.3 6.2
19.2 17.8-
0.2 0.6
0.2 0.5
0.3 1.0
2.4 4.6












and Analytical Activities to Determine
Ambient Air Concentrations of Selected Toxic Pollutants in Baltimore,
Maryland,
April 18, 1984.

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     We determined  the total  population  in  the  Baltimore  study
area, approximately 1.5 million, using 1980 census data provided by
the Baltimore Regional Planning Council.  [We describe the boundaries
of the study area—the contiguous urbanized areas of greater Balti-
more—in Chapter  II.]  We  then subdivided the  data  and  assigned
subpopulations to  each of  the  10 monitoring  locations  (see  Table
V-4) considering  land  usage and proximity to the  monitoring  site.
The population  apportionment  was needed  to  calculate  aggregate
incidence.  We estimated exposure by multiplying the ambient levels
at each monitoring  location by the subpopulation  assigned  to each
site.

     In traditional  air analyses,  dispersion models  are  used to
calculate ambient  levels  and  the resulting population  exposures.
However, we could not utilize dispersion modeling in Phase I because
of limitations in our source and emissions data.

Unit Risk Factors

     For each of  the  organic compounds considered in the analysis,
with the exception of 1,2-dichlorbpropane (which we discuss below),
we used EPA's GAG potency data  for cancer effects.  For non-cancer
effects, RID toxicologists developed thresholds for health effects.
We summarize our  findings in each area.

     Cancer

     Table V-5  lists the cancer unit risk  factors available for
the pollutants  considered  in  the analysis.  We  present the unit
risk values  that  were used at  the   time  Phase  I  was  completed
(1985), as  well  as  the  values  that  are  currently  available.
The most  notable changes  are  for 1,2-dichloroethane and  chloro-
form, for  which  the  estimated  potency  increased  nearly  three-
fold and slightly more than  twofold, respectively; and trichloreth-
ylene and perchloroethylene, for which the estimated potency decre-
ased by more  than half.  CAG  revised the cancer  unit risk  factor
for benzene upward by a modest amount.

     In this  field,  scientists  generally do  not  consider   such
revisions significant.  Given the considerable uncertainty associated
with many steps  in  the process  of estimating  cancer potency,  small
changes in  the  order  of  two  or three are  not  considered major-

     As shown  in Table V-5,  EPA  does  not  currently   regard as
carcinogens all the pollutants that are considered.  In particular,
EPA does not consider  ethyl benzene, toluene, and  xylene carcinogenic
(As a result, we did not have a  unit risk factor for these chemicals).
However, exposure  to  ethyl  benzene,   toluene,  or xylene  at high
ambient levels may  increase  the  risks of  noncancer health effects.

     All unit risk  factors  presented  in  this  table were developed
by CAG, with the exception of 1,2-dichloropropane.
                                V-10

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                     Table V-4

 BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS

  EXPOSED POPULATION:  ORGANICS IN THE AMBIENT AIR
                                        Total
        Monitoring Site           Exposed Population

Guilford                                333,186
Northeast Police Headquarters           745,187
Southwest Police Headquarters           285,517
Holabird Elementary                      48,771
Oundalk                                  14,270
Chesapeake Terrace Elementary            12,880
Sun and Chesapeake                       16,848
Ft. McHenry                              23,997
U.S. Coast Guard Yard                     8,416
Riviera Beach                            44,642
  Total                               1,533,714
Source:  Regional Planning Council, Baltimore,
         Maryland, Census '80;  Population and
         Housing Characteristics by Census Tract,
         April 1982.

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                               Table V-5

           BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS

                 UPPER-BOUND CANCER UNIT RISK VALUES:
                      ORGANICS IN THE AMBIENT AIR
                               Inhalation (ug/m3)
                    -1
   Pollutant

Benzene
Trichloroethylene
Perchloroethylene
1,2-Dichloroetha ne
Chloroform
Carbon Tetrachloride
1,2-Oichloropropane
Ethyl Benzene
Toluene
Xylene
  1985
Analysis
      ID'"
      io-6
6.9 x
4.1 x
1.7 x
7.0 x
1.0 x
1.5 x
1.8 x 10"5

    *
    *
 Revised
   19862
8.0 x
1.3 x
      io-6
4.8 x 10-7
      10-5
      10-5
      10-5
1.8 x 10°
              2.6 x
              2.3 x
              1.5 x
  Grouping
  Based on
EPA Criteria3

     A
     B2
     B2
     82
     B2
     B2
     C
•Current EPA policy does not regard ethyl benzene, toluene, or xylene
 as a carcinogen.

IThe unit risk factors presented in this column were developed in 1985
 and used in the preliminary Phase I risk calculations.
2The unit risk factors presented in this column are current as of
 5/7/86.
5EPA weight-of-evidence classifications:
 A = human carcinogen; B2 = probable carcinogen; C = possible
     carcinogen.  (See Appendix A for more detail.)

Source:  All cancer unit risk factors were developed by EPA's.
         Carcinogen Assessment Group, except for 1,2-dichloropropane.
         RID calculated the unit risk factor for 1,2-dichloropropane
         using the linearized, multi-stage model and data from a 1977
         NTP study.  The NTP study is currently undergoing EPA review;
         thus, the potency value could change.

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RID toxicologists and  consultants  calculated  a unit  risk  factor
for 1,2-dichloroprapane from  a potency  (qi*)  value developed  for
EPA1s' Drinking  Water  Criteria  Document on  DCP (March  2,  1984).
The potency  (qi*)  value was  based on  a 1983 National  Toxicology
Program (NTP)  study.4   While the  NTP  study can  be  used  as  a
preliminary basis for evaluating  risks to human health,  we  should
note that the Drinking  Water Criteria Document on DCP,  and  thus  the
NTP study, are  currently undergoing  EPA review.  As a  result, this
unit risk factor is subject to change.

     Noncancer Health Effects

     Table V-6 details  the noncancer health effects  and the thresh-
olds above  which there  is  an increased  risk  of  those  effects.
These values  were  developed  by  RID  toxicologists.   The  disease
categories considered include the following systemic effects:
fetal development effects; liver toxicity;  neurobehavioral  effects;
kidney toxicity; reproductive effects; and other, e.g.,  respiratory
difficulties, anemia,  and leukopenia.

Preliminary Screening Analysis and
Risk Assessment Results

     We calculated  and  evaluated  three  measures of risk  posed by
exposure to  each  of  the  organic  compounds  considered   in  our
preliminary investigation:  excess  aggregate   annual  incidence  of
cancer; lifetime  individual  cancer  risks  at  the  site  of  maximum
concentration (a  surrogate for MEI  risks);  and the potential  for
noncancer health  effects.   We  describe the  calculations, used to
derive each measure of risk and the results below.

     Aggregate Cancer Incidence

     We calculated  the annual  excess  cancer incidence  for  each
pollutant by  first  multiplying the  ambient concentration  at each
monitoring site  by  the exposed  subpopulation and  the  appropriate
cancer unit  risk  factor,  summing across all  sites  for  each pollu-
tant, and then dividing by 70 (the  standard  EPA  assumption regard-
ing the  number  of  years  in  a  lifetime).   Table V-7  presents  the
upper-bound estimates of annual cancer  incidence for each pollutant
using the unit  risk factors  from the  initial  Phase  I  analysis  and
those currently available.

     Please note  that  small  differences  (a  factor  of  two  or
three) between  numbers  in  the following  tables do not necessar-
ily warrant  the conclusion  that  one  chemical is  twice or three-
times the  risk  of  another.   The  precision  in  this  screening
exercise does not allow the making of such quantitative
                                V-ll

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Table V-6 ,

BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS

Pollutant
Benzene
Trichloroethylene
Perchloroethylene
1, 2-Dichloroethane
Chloroform
Carbon Tetrachloride
1,2-Oichloropropane
Ethyl Benzene
Toluene
Xylene
*The threshold values
NONCANCER HEALTH EFFECTS AND, PRESUMED
ORGANICS IN THE AMBIENT
RID-Oerivec
Threshold
Health Effect (uq/m^j
Fetal developmental 4. 1
Blood effects *
Liver 26
Neurobehavioral 26
Kidney 3770
Fetal developmental 909
Liver 69.9
Kidney 69.9
Liver 26
Neurobehavioral 26
Gastrointestinal 26
Kidney 26
Fetal developmental 2.4
Liver 69.9
Neurobehavioral 11.7
Fetal developmental 24.2
Liver 2.4
Neurobehavioral 2.4
Kidney 108
Reproductive 430
Liver . 308
Kidney 308
Liver 340
Fetal developmental 476
Liver 1,010
Neurobehavioral 580
^Kidney 1,010
Reproductive . 500
Respiratory 1,010
HUMAN THRESHOLDS:
AIR1
Source
Kuna & Kapp 1981
Snyder et al. 1980
Unverified 1985 ADI
Grandjean et al. 1955
Tucker 1982
Nelson et al. 1979
Coler & Rossmiller 1953
NCI 1977
Kozik 1957
Kozik 1957
USEPA 1982a
Heppel et al. 1946;
Hoffman et al. 1971
Sen wet z et al. 1974
Hey wood et al. 1979; 1986 ADI
Challen et al. 1958;
USEPA 1985
Schwetz et al. 1974
EPA 1980 & 1984; Smyth 1935 & 1936
Moller 1973
EPA 1980
Adams et al. 1952
Basu et al. 1984; NTP 1983
NTP 1983
Verified 1986 -ADI; Wolf et al. 1956
Hudak & Ungvary 1978
USEPA 1983
Hanninen et al. 1976; Seppalainen et al.
1978
USEPA 1983
Matsumoto et al. 1971
Von Oettingen et al. 1942; Bruckner &
Peterson 1981
Fetal developmental 52.8 Ungvary et al. 1980
Liver 215 Bewers et al. 1982; Tatrai et al. 1981
Neurobehavioral 215 USE PA 1984; Savolainen et al. 1979
Respiratory 215 Hipolito 1980; Smyth & Smyth 1928
Cardiovascular 215 Hipolito 1980; Hirsch 1932
Anemia and leukopenia 215 Browning 1965; Hipolito 1980
presented in this table were developed by RID and are current as of 5/7/86.
•These threshold effect levels are currently undergoing review
Assessment Office.
by EPA's Environmental Criteria and

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                         Table  V-7

     BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS

  UPPER-BOUND ESTIMATES OF ANNUAL EXCESS CANCER INCIDENCE:
                 ORGANICS IN THE AMBIENT AIR

      PHASE I RESULTS INTENDED FOR DEVELOPMENT OF THE
                  PHASE II RESEARCH AGENDA
                                 Upper-Bound Annual Cases1,2

        Pollutant                  1985          Revised
  (weight of evidence)3          Analysis*        19865

Benzene (A)                        1.6             1.8
Trichloroethylene (B2)             0.1             0.02
Perchloroethylene (B2)             0.2             0.1
1,2-Dichloroethane (B2)            0.04            0.1
Chloroform (B2)                    0.2             0.4
Carbon Tetrachloride (82)          0.3             0.3
1,2-Oichloropropane (C)    .        0.1             0.1

  Total                            2.5             2.8
XTHE UNIT RISK FACTORS USED IN THIS ANALYSIS.ARE BASED ON
 CONSERVATIVE ASSUMPTIONS THAT GENERALLY PRODUCE UPPER-BOUND
 ESTIMATES.  BECAUSE OF LIMITATIONS IN DATA AND METHODS  IN
 SEVERAL AREAS OF THE ANALYSIS, SUCH AS EXPOSURE CALCULA-
 TIONS AND POLLUTANT SELECTION, RISK ESTIMATES WERE CALCU-
 LATED AS AIDS TO POLICY DEVELOPMENT, NOT AS PREDICTIONS OF
 ACTUAL CANCER RISKS IN BALTIMORE.  ACTUAL RISKS MAY  BE  SIG-
 NIFICANTLY LOWER; IN FACT, THEY COULD BE ZERO.  THE  PROPER
 FUNCTION OF THE ESTIMATES IS TO HELP LOCAL OFFICIALS SELECT
 AND EVALUATE ISSUES AND SET PRIORITIES FOR THE TOPICS
 EXAMINED.
2RID'S ESTIMATE OF THE ACTUAL NUMBER OF CANCER CASES  IN  THE
 STUDY AREA IN 1984 IS 8,000 CASES.  (SEE 11-8 AND 9.)   THIS
 NUMBER SHOULD SERVE ONLY AS A POINT OF REFERENCE IN  UNDER-
 STANDING THE RISK ESTIMATES PROVIDED.  IN ADDITION,  THE
 RISK ESTIMATES SHOULD NOT BE INTERPRETED AS REPRESENTING
 THE TOTAL UPPER-BOUND CANCER RISKS FROM ALL POLLUTANTS  IN
 ANY PARTICULAR MEDIUM.  THEY DO NOT TAKE INTO ACCOUNT ALL
 POLLUTANTS THAT MAY BE PRESENT IN THE MEDIUM, ALL SOURCES
 OF THESE POLLUTANTS, AND ALL EXPOSURE SCENARIOS  INVOLVING
 PATHWAYS OR EXPOSURES OF SHORT DURATION TO RELATIVELY HIGH
 DOSES.
'EPA weight-of-evidence classifications:  A = human  carcino-
 gen; B2 = probable carcinogen; C  = possible carcinogen.
 (See Appendix A  for more detail.)
*The incidence estimates listed in this column were  calcu-
 lated using cancer unit risk values developed in 1985.
5The incidence estimates listed in this column were  calcu-
 lated using current (5/86) cancer unit risk  values.

-------
distinctions.  At best we can state that one chemical qualitatively
poses greater  risk  than  another.  Benzene  is  clearly a greater risk
than all  other  chemicals  examined,  but  carbon  tetrachloride  can
not be said to be much worse than chloroform.

     This preliminary  analysis  suggests that exposure to  a subset
of organics  found  in the ambient air may result  in an upper bound
estimate of  about  3 excess  cancer  cases  a  year  (the revised unit
risk factors do not dramatically change the findings).  Benzene ex-
posures alone  account  for  almost two-thirds  of the total estimated
excess cancer  incidence.  Perchloroethylene,  chloroform,  and carbon
tetrachloride  together contribute  less  than  one  case per  year,  or
most of the remaining third for  the subset of pollutants considered.

    Upper Bound Lifetime Individual Cancer Risks

     We estimated upper  bound lifetime individual  cancer  risks  by
multiplying the  maximum observed  ambient concentration  for  each
pollutant by the appropriate unit risk factor.   Table V-8 details
the calculated upper-bound  lifetime  cancer  risks,  as well  as the
number of  people exposed  to thesemaximum   concentration levels.

     Using the 1985  unit risk factors,  upper-bound lifetime cancer
risks range  from close to 2  chances  in 100,000  (trichloroethylene
and perchloroethylene) to  almost 9  chances   in  100,000  (benzene).
The revised unit risk factors result  in  a wider spread of estimates,
ranging from a low  of  roughly 0.5  chances in a 100,000 (perchloro-
ethylene to a high of about 10 case in 100,000 for both benzene and
chloroform.  The most noticeable change  is for chloroform,  for which
the estimated lifetime individual cancer risk increases by a factor
of slightly more than two.
                                       \
     Noncancer Health Effects

     We assessed  the potential  for  noncancer  health effects  by
comparing the  measured  ambient  concentration  with   the  no-ffect
threshold levels of  each individual pollutant.   In general, there
should be a concern  over the possibility  of  adverse health effects
if the ambient concentrations exceed  the  threshold.  The degree of
concern should be gauged  by  the number of people potentially exposed
and the extent to which the threshold is exceeded.

     A comparison of ambient levels at each of the monitoring sites
to the no-effect threshold levels indicates  that there may, be  an
increased risk of noncancer health effects for  benzene and chloro-
form exposures.  In the case of benzene, the ambient levels at each
of the ten monitoring sites  exceed the no-effect threshold  for fetal
development effects.  Ambient chloroform levels at monitoring sites
#6, #7,  and  #8  also exceeded  the  no-effect  threshold  for fetal
development effects.
                                V-12

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                                 Table V-8

             BALTIMORE KMP PRELIMINARY RISK SCREENING RESULTS

         UPPER-BOUND ESTIMATES OF LIFETIME INDIVIDUAL  CANCER RISKS
   AT SITE OF MAXIMUM AVERAGE CONCENTRATION:  ORGANICS IN THE AMBIENT  AIR

              PHASE I RESULTS INTENDED FOR DEVELOPMENT OF THE
                          PHASE II RESEARCH AGENDA
                                   Upper-Sound Lifetime
                                 Cancer Risk (inhalation)1,2

        Pollutant                  1985          Revised         Exposed
  (weight of evidence)3          Analysis4        19865        Subpopulation

Benzene (A)                     8.9 x 10~5      1.0 x 10"*        48,771
Trichloroethylene (B2)          1.6 x 10~5      5.1x 10"6        48,771
Perchloroethylene (B2)          1.6x10"'      4.5. x 10"*        14,270
1,2-Oichloroethane (B2)         1.8 x 10"5      6.8 x 10~5        12,880
Chloroform (B2)                 4.7 x 10~5      1.1 x 10~4        23,997
Carbon Tetrachloride (B2)       2.1 x 10~5      2.1 x 10~5        23,997
1,2-Dichloropropane (C)         3.6 x 10~5      3.6 x 10~5        16,848
JTHE UNIT RISK FACTORS USED IN THIS ANALYSIS ARE BASED ON CONSERVATIVE
 ASSUMPTIONS THAT GENERALLY PRODUCE UPPER-BOUM) ESTIMATES.  BECAUSE OF
 LIMITATIONS IN DATA AND METHODS IN SEVERAL AREAS OF THE ANALYSIS, SUCH AS
 EXPOSURE CALCULATIONS AND POLLUTANT SELECTION, RISK ESTIMATES MERE CALCU-
 LATED AS AIDS TO POLICY DEVELOPMENT, NOT AS PREDICTIONS OF ACTUAL CANCER
 RISKS IN BALTIMORE.  ACTUAL RISKS MAY BE SIGNIFICANTLY LOWER; IN FACT, THEY
 COULD BE ZERO.  THE PROPER FUNCTION GF THE ESTIMATES IS TO HELP LOCAL
 OFFICIALS SELECT AND EVALUATE ISSUES AND SET PRIORITIES FOR THE TOPICS
 EXAMINED.
^Individual risks were calculated using the maximum average concentration
 measured across all monitoring sites.
3EPA weight-of-evidence classifications:  A = human carcinogen;
 B2 = probable carcinogen; C = possible carcinogen.  (See Appendix A for
 more detail.)
*The risk estimates shown in this column were calculated using cancer unit
 risk factors available in 1985.
•*The risk estimates listed in this column were calculated using current
 (5/86) unit risk factors.

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     We  used  statistics on  the number  of  births occurihg  in the
 Baltimore area  to  identify the subpopulation exposed to the higher
 levels of benzene.   In 1984,  this  number was 27,426.  Please note,
 however, that  the  total number of pregnancies  (successful  and un-
 successful) that occur at any  one time are likely  to  exceed  by a
 considerable amount the number of pregnancies that successfully come
 to  terra.  Furthermore, we do not even know the number of pregnancies
 that come  to  term in  the  areas around  the  three  monitoring sites
 (sites number  6,7  and  8)  and  hence have  not  estimated the  sub-
 populations in  these areas who are also exposed to higher levels of
 chloroform.  Thus our estimates of  exposed subpopulations are likely
 to  be underestimated.

      We must  reiterate that the threshold values that  RID calcu-
 lated are  not   official  EPA values.   In this  screening  exercise,
 these values serve only to identify chemicals  that warrant  greater
 regulatory attention.   Much  more study  is  needed  to determine how
 much the ambient  levels for these pollutants  actually contribute,
 if  at  all,  to adverse health  effects  in these  subpopulations.

 Limitations

     As with  most  analyses,  there  are  limitations  that must  be
 carefully considered when interpreting the results.  At the  beginn-
 ing of this chapter, we mentioned the limitations of risk assessment.
 In  this  section,  we  list  the major  uncertainties  associated  with
 the scope of  our  analysis and  the exposure data  used to estimate
 risks from organic pollutants in the ambient air.

     First, we  must  emphasize that  this  preliminary investigation
 considered only ten organic compounds.  While the study participants
 agreed that analysis of this limited set of pollutants was sufficient
 for guiding decisions  on Phase II  study topics,  the  results  from
 such analysis should .not be construed as definitive.  Phase  II will
 explore a wider group  of pollutants,  and  the results  from  this
 effort may be different than those presented here.

     Second, the use  of Tenax  GC as  the absorbent  may  introduce
 a bias  in   our results for   certain compounds.   Although  Tenax
was considered  the  best sampling  medium at the  time we  conduc-
 ted our  ambient air  monitoring,  its  reliability  has been  called
 into question  in the last ±wo years;  EPA is currently exploring an
alternative to Tenax.

     Third,  the ambient air  monitoring data may not  be representa-
 tive of actual pollutant concentrations in the Baltimore metropolitan
area.   We selected sites near point sources because of our interest'
in verifying emission estimates from these sources at some point in
the future.   Limited  resources prevented us  from pursuing  a  more
                                V-13

-------
elaborate sampling  program.   As  a  result,   the  ambient  data  we
collected may  not  adequately  represent  actual  receptor  ambient
levels because we could not site monitors throughout the entire study
area.

     Fourth, our  usage  of average ambient  values masks  the  peaks
in concentrations  that  individuals  are  exposed  to daily.   Thus,
our risk  calculations  may understate  the total  body burden  from
exposures to organics in the environment.   This applies to carcino-
genic as well as noncarcinogenic effects.

     Finally, though we  calculated the lifetime  risks to  the MEI
using the  maximum  observed  concentrations,  it  is unlikely  that
these samples  were taken  at  the point  of maximum concentration.
Thus', we  may  have underestimated  lifetime  risks to  the MEI for the
pollutants considered.   We simply can not  estimate the  how  these
uncertainties affect our risk estimates.

METALS IN THE AMBIENT AIR AND LEAD IN THE GENERAL ENVIRONMENT

     The  second  topic  nominated  by  the Human  Health Subcommittee
for further investigation in Phase II was metals in the ambient air
and lead  in the  general environment.  Metals are released from many
sources, are  commonly   detected  in  the  ambient   air, and  can  be
associated with  acute and  chronic adverse health effects.

     Unlike the analysis of organics, we relied  entirely on existing
information to   assess  the  exposures  and  risks   associated  with
metals in the ambient  air and did not generate new data.  We also
utilized  available ambient air  quality  data  to  determine ambient
concentrations.   We describe the data used  in our analysis and our
findings  in more detail below.

     Because  of   the  ubiquity  of  lead  in  the environment,   the
risk from exposures  to lead could not be  examined  solely from  the
perspective of ambient air.  Consequently, other  routes of  exposure
were also considered for this metal in evaluating its  importance as
a  risk to human  health in  the study area.

Pollutants

     While many  metals are  found throughout  the  environment,  the
Technical Advisory Committee  focused  our   information   gathering
efforts  on  four heavy metals:  cadmium,  chromium,  lead, and  zinc.
These pollutants were  selected because they  were  considered  to be
reasonable  indicators  of  the potential human health risks  from  all
metals in the ambient  air.  There were also  many  known  sources  of
these pollutants.


      It  is  important  to  note that  chromium  can have two  valence
states:   trivalent and hexavalent.   While  there is  currently
insufficient health data  to  suggest  that  trivalent  chromium
poses a  threat  to human  health,  hexavalent   chromium is a  proven


                                 V-14

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human carcinogen.   We  attempted  to  distinguish between  these  two
valence states/ where possible, but found that information was only
available for  total chromium.   As  a  result,  we used  sensitivity
analysis to explore how  differing'assumptions about the  levels  of
hexavalent chromium  as a fraction of  the  total  (e.g.,  100 percent
vs. 1 percent  of  total  chromium)  would  affect  our estimates  of
risk.

     Sources


     The metals  of  concern in this  study  are released to the  air
from both area  and point  sources.   Cadmium is released  from fuel
combustion and  road vehicles; trace amounts  are also  emitted from
the burning of used oil.   The major  point  sources  emitting cadmium
are electroplaters and large industrial boilers.

     While the valence state  of  chromium  from  specific  sources  is
not known, the  following  generalizations can be made  on  the basis
of existing information.    Trivalent  chromium  is  usually associated
with steel,   ferrochromium, refractory,  and  cement  manufacturing,
chromium ore refining,  and coal and  oil   combustion.   Hexavalent
chromium may be emitted by  such sources as chromium chemical plants,
sewage sludge and municipal refuse incineration, and cooling towers*

     Lead is  emitted to  the   ambient  air  in large  part by road
vehicles, although  these  loadings  will  decline  as the lead  in
gasoline is phased  out.   Other  area  sources  of lead  include used
oil combustion,  which  will also become  less significant  with  the
lead phasequt,   and  heating.   Lead  is also released  from several
point sources,  such as  steel   mills,  municipal  waste incineration,
and utility boilers,  but  these  emissions  do  not  appear  to  be  as
significant as those from area sources.

     Other sources  of lead to which  people, particularly children,
are exposed are street, backyard or playground, and household dust.
Lead in  the  ambient air  settles over  time  in  outdoor,   and to a
lesser extent,  indoor dust.   Another  important  source  is lead from
lead-based paint which can be ingested directly in  paint chips or
becomes a constituent of  household dust.

     Finally,  zinc  is  emitted from  only  a  few  known  sources  in
the Baltimore  study area,  and these  releases are  small.  Heating
and used  oil  combustion are  the principal area  sources emitting
zinc.  Trace amounts are  also released by sewage sludge incineration.

Ambient Levels

     We were able to locate ambient  air quality data  for three of
the four pollutants: lead,  chromium (total), and cadmium.  The data
were obtained from  the 1982 Annual  Air Quality Data Report for  the
State of  Maryland  and were  judged  sufficient  for  characterizing
average concentrations for the Phase I screening activities.
                                V-15

-------
          The  values  used  for  cadmium  deserves  special  attention be-
      cause no  cadmium  was  actually detected  at  any  of  the monitoring
      sites.  Instead,  the values  for cadmium were derived from the
      lowest  concentrations  that could be detected by the monitoring and
      analytical  instruments and hence  are  likely  to overestimate actual
      average cadmium  levels at  the monitoring sites.  The use of these
      values  allows  us  to place an upper bound on the possible risk posed
      by  cadmium.  It cannot serve as an even a rough estimate of actual
      risk.   We  also substituted  detection  limit values for  chromium
      where actual concentrations  were below detection  limits.

          Table  V-9 summarizes the average  ambient concentrations found
      at  9  monitoring  sites;  Figure V-2  shows the  locations  of  these
      sites throughout  the study area.  A more detailed discussion of the
      metals  monitoring program can  be found  in  the  State  of Maryland
      report.

          Exposed Population

          As in  the organics analysis,  we  used a 5-km.  grid system  to
      partition the  study area population.  The population in each grid
      section was then  assigned  to a monitoring site that was considered
      most representative based on land use and  proximity.   Table V-10
      lists the exposed  subpopulation  corresponding to  each monitoring
      site.

      Unit Risk Factors

          Cancer

          Of the four  pollutants considered,  cancer  unit  risk factors
      were available only   for  cadmium  and  hexavalent   chromium   (see
      Table V-ll).   EPA  does  not currently regard  trivalent  chromium,
      lead, or  zinc as  carcinogenic through inhalation.  However,  there
      is  limited  evidence that some  lead  compounds induce tumors in ex-
      perimental  animals.  GAG is  reviewing these  data,  but has not yet
      made a  determination  as to  the potential carcinogenicity of  lead.

          Noncancer

          Table  V-12  lists  the   noncancer  health effects  for cadmium,
      hexavalent  and trivalent chromium,  and  zinc.   The health effects
      data for  lead are currently  undergoing  internal  review  and  are,
                                      V-16
'in'1 mw

-------
 Pollutant

 Lead

 Chromium

 Cadmium2

 Zinc
  A

0.29

0.01

0.00

N.A.
  B

0.40

0.03»

0.00*
                  Table V-9

BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS

    AVERAGE MEASURED AMBIENT CONCENTRATIONS:
           METALS IN THE AMBIENT AIR1

                     (ug/m3)


                     Site

              K        M

            0.48     0.33

            0.03     0.01

            0.00     0.00
  C

0.49

0.03*

0.00*
  N        0        P        Q

0.49     0.23     0.23     0.47

0.00     0.02**   0.02     0.02**

0.00     0.00**   0.00     0.00**

N.A.     N.A.     N.A.     N.A.
Sites

A:  Northeast Police Headquarters
B:  Guilford
C:  Southwest Police Headquarters
K:  Fire Department
M:  Essex
N:  Glen Burnie
0:  Sellers Point
P.  Canton Pier 4
Q:  Southeast Police Headquarters
  Average
Across Sites

   0.38

   0.02

   0.00

   N.A.
     concentration estimates were rounded to two significant decimals.
^Average measured ambient concentrations for cadmium were .001 ug/m  at sites A, B, C, K, M, and  N;
 cadmium concentrations at sites 0, P, and Q were .002 ug/m3.  These concentrations are in the range  of
 detection limits.

N.A. = Not available.

 » = No data available for this site; estimates based on station K because of proximity and similar
     meteorological conditions.
*» = No data available for this site; estimates based on station P because of proximity and similar
     meteorological conditions.

Source:  Stste of Maryland, 1982 Annual Air Quality Data Report for the State of Maryland.

-------
-f
A
B
C
D
E
F
G
H
I
J
K
L
M
N
0
P
Q
R
S
                               CO*. DMMH
                                                                  THE BALTIMORE IEMP
                     BALTIMORE CITY
                                 Bs
                                K
   LEGEND

   NEPD
   GUILFORD
   SWPD
   FT. MCHENRY
   SUN /CHESAPEAKE
   HOLABIRD ELEMENTARY
   COAST GUARD
   DUNDALK
   RIVIERA BEACH
   CHESAPEAKE TERRACE
   FIRE DEPT.
   195
   ESSEX
   GLEN BURNIE
   SOLLERS POINT
   CANTON PIER 4
   SEPD
   FORT HOLABINE
   OLD TOWN
                                                      BALTIMORE COUNTY
                                              Q
                                       Sparrows Point
                Glen Burnle
• BWI Airport      -IJ +



 ANNE ARUNDEL COUNTY

-------
                      Table V-10

   BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS

    EXPOSED POPULATION:  METALS IN THE AMBIENT AIR

                                           Total
      Monitoring Site               Exposed Population

Northeast Police Headquarters              672,036
Guilford                                   181,166
Southwest Police Headquarters              233,500
Fire Department (near Guilford)             76,024
Essex                                       92,251
Glen Burnie                                159,693
Sellers Point                               24,372
Canton Pier 4                               27,655
Southeast Police Headquarters               66,384

  Total                                  1,533,081
Source:  Regional Planning Council, Baltimore, Maryland,
         Census '80:  Population and Housing Character-
         istics by Census Tract. April 1982.

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                         Table V-ll

     BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS

            UPPER-BOUND CANCER UNIT RISK VALUES:
                 METALS IN THE AMBIENT AIR
                       Inhalation (ug/m3)
      -1
                         1985
Pollutant              Analysis1

Cadmium                2.3xlO~3
Chromium (hexavalent)  1.2xlQ-2
Chromium (trivalent)      *
Lead                      »
Zinc                      »
 Revised
  19862
1.8xlO~
1.2x10'
      ,-2
   *
   *
  Grouping
Based on EPA
  Criteria3

     Bl
     A
•Current EPA policy does not regard trivalent chromium, lead
 or zinc as carcinogens.  As a result, we could not perform
 a risk assessment for these compounds.
*The unit risk factors presented in this column Mere
 developed in 1985 and used in the preliminary Phase I risk
 calculations.
2The unit risk factors presented in this column are current
 as of 5/7/86.
3EPA weight-of-evidence classifications:
 A = human carcinogen; Bl = probable carcinogen.  (See
 Appendix A for more detail.)

Source:  All cancer unit risk factors Mere developed by
         EPA'a Carcinogen Assessment Group.

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                                                  Table V-12

                             BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS

                          NONCANCER HEALTH EFFECTS AND PRESUMED HUMAN THRESHOLDS:
                                       METALS IN THE AMBIENT AIR1
                                                    RID-Derived
                                                     Threshold
   Pollutant
Cadmium
Chromium (hexavalent)
Chromium (trivalent)
Zinc
  Health Effect

Fetal developmental
Liver
Respiratory
Kidney
Reproductive

Fetal developmental
Liver
Ulceration/perforation
  of nasal septum
Reproductive

Fetal developmental
Liver
Kidney

Reproductive
21.0
0.42
2.0
0.24
119

17.0
17.0

17.0
17.0

3,500
3,500
3,500

1,540
                 Source

 Schroeder & Kitchener 1971
 Friberg 1950
 Comm. European Communities 1978
 Kjellstrom et al. 1977
 Scharpf et al. 1972

 Gale 1978
 NIOSH 1975

 NIOSH 1975
 Gale 1978

.Clement; unverified ADI
 Clement; unverified ADI
 Clement

 Schicker & Cox 1968
  he threshold values presented in this table were developed by RID and are current as of 5/7/86.

-------
therefore, unavailable  for  our  use  at  this  time.    There  is,
however, strong  scientific evidence  that airborne  lead can  have
adverse health  impacts,  particularly  for children.   These  health
effects include  blood-related  problems  and neurological  dysfunc-
tions, such as potential  impairment  of intelligence  as  measured in
IQ tests. . At low levels of exposure, lead can also lead to increased
hypertension in adult males.

     We could not estimate total  exposure to lead; hence  we  could
not evaluate  the  relative importance  of  ambient  lead to  total
non-cancer risk from lead.   As a surrogate for an estimate of
total exposure,   we used  the  number  of  hospitalizations  for  lead
chelation therapy  as  an indication of  the  potential public health
threat posed by  the presence of  this element in  the  environment.
Lead chelation  therapy is used  to  filter lead  from  the  blood;
however, it  cannot help  reverse damage that has  already occurred,
especially for  neurobehavioral  effects.   Clearly, the  use of this
surrogate represents a lower bound  of the importance of non-cancer
health effects of  lead.

Preliminary Screening Analysis and
Risk Assessment Results

     We assessed  the impact of metals  on  human health using the
three of  the  four  measures  of  risk  discussed  earlier:   annual
cancer incidence;  lifetime individual cancer risks  at  the site of
maximum concentration  (a surrogate for MEI risks); and the increased
potential for noncancer  health effects.  We  calculated the excess
aggregate incidence of cancer for each pollutant by first  multiplying
the ambient  concentration at each  monitoring  site  by  the exposed
subpopulation, summing  this  product  across  the  sites,  and then
multiplying this  sum by  the  appropriate cancer  unit  risk factor.
We then divided by 70 to estimate annual  incidence.

     We computed  upper-bound lifetime  individual cancer  risks by
multiplying the  maximum  average  ambient  concentration  for  each
metal by  the corresponding unit risk  factor.   Finally,  we  compared
the ambient  air  levels with the  no-effect  thresholds to  determine
whether these concentrations presented  levels of .regulatory concern
for noncancer   health effects.   We  present  our results  for each
measure of risk below.

Cancer Incidence

     Since cancer  unit risk factors were  only available for hexava-
lent chromium  and  cadmium,  we  could only  assess  the risks  from
exposure  to  these  two  metals.   Without any knowledge of the  actual
ambient levels  of  hexavalent  chromium,  we evaluated   a  range of
possible  concentrations  (100 percent,  50  percent,  10 percent,  1
percent,  and 0% of total chromium levels).  Zero  percent is possible
for the reasons  explained  above.   in  this case,  the  cancer risk for
cadmium Would be  negligible given  current information on the  carci-
nogenicity of  other  prevalent  species  of  chromium.    Our  results
                                 V-17

-------
suggest that exposure  to chromium and  cadmium  could result  in  an
excess (upper-bound estimate)  of  a negligible number to  an upper-
bound estimate of roughly 4 excess cancer cases  per year (see Table
V-13); the  risks  are  almost   entirely  due  to  chromium  ambient
levels and  the  fraction  of   chromium  assumed  to be  hexavalent.
Future initiatives  to  better  quantify  the ambient  concentrations
of hexavalent  chromium,   as   well  as  its  sources,  could  reduce
the uncertainty of such risk assessments.

    Upper-Bound Lifetime Individual Cancer Risks

     Table V-14 presents the upper-bound lifetime individual
cancer risks from hexavalent  chromium  and cadmium.  As  mentioned
above, we assumed detection level  values  for cadmium and chromium
whenever we were  unable  to detect  the metals  at  a monitoring site.
Thus, the actual monitored concentrations were below analytical
detection levels.Using the detection level value rather than zero
(or someothervalue  smaller  than the  detection level  value)  for
the monitored  concentration  serves to overestimate  actual  ambient
air exposures and hence risk from both metals.

The upper-bound lifetime cancer risks  for  cadmium, using the current
CAG unit risk factor and assuming the detection  level value for its.
concentration in the ambient air,   is  roughly  4 chances in a million
(5 chances based upon 1985 CAG value).  This  estimate of risk from
cadmium is presented only  to show the extent to  which  we are able
to detect a significant risk to human  health from  the metal.  Since
the real ambient concentration is less than the  value we used, we
can state with reasonable confidence,  for the purpose of this~
screening analysis, that cadmium does not pose a significant cancer
risk through ambient exposures.

     Also, uncertainties in the ambient levels of hexavalent
chromium forced  us  to consider  a wide  range of  possible  average
concentrations.  This was  useful because  Phase  I was  a screening
exercise to identify possible problems requiring greater regulatory
attention and not an attempt  to estimate absolute risk.  The range
of potential upper-bound lifetime  cancer  risks   for  chromium spans
two orders of  magnitude,  from a negligible value  (if 0 percent  of
total chromium is  hexavalent)  to  roughly 4 chances in  10,000 (if
100 percent of total chromium is hexavalent).  The average ambient
level is  also  overestimated because  the  value  for the detection
level was used whenever the  metal was not detected at a monitoring
site (and hence  its actual  concentrations were below the level  of
detection).
                                V-18

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                      Table V-13

              BALTIMORE  IEMP PRELIMINARY
                RISK  SCREENING RESULTS

            UPPER-BOUND  ESTIMATES OF ANNUAL
                EXCESS CANCER INCIDENCE:
               METALS IN THE AMBIENT AIR

    PHASE I RESULTS INTENDED FOR DEVELOPMENT OF THE
               PHASE  II  RESEARCH AGENDA
                                                  1  7
                         Upper-Bound Annual Cases  ,'

     Pollutant               1985         Revised
(weight of evidence)3      Analysis4       19865

Chromium (A)
—Total hexavalent           4.2          4.2
—SOS hexavalent             2.1          2.1
—10% hexavalent             0.4          0.4
—IS hexavalent              0.04          0.04
—OS hexavalent              0.00          0.00
Cadmium6 (81)           0.00 to  0.05    0.00 to 0.04
 Total                  0.00 to 4.25   0.00 to  4.24
*THE UNIT RISK FACTORS USED IN THIS ANALYSIS ARE  BASED
 ON CONSERVATIVE ASSUMPTIONS THAT  GENERALLY PRODUCE
 UPPER-BOUND ESTIMATES.  BECAUSE OF LIMITATIONS IN DATA
 AND METHODS IN SEVERAL AREAS OF THE ANALYSIS,  SUCH  AS
 EXPOSURE CALCULATIONS AND POLLUTANT SELECTION, RISK
 ESTIMATES WERE CALCULATED AS AIDS TO POLICY DEVELOP-
 MENT, NOT AS PREDICTIONS OF ACTUAL CANCER RISKS IN
 BALTIMORE.  ACTUAL RISKS MAY BE SIGNIFICANTLY  LOWER;
 wrnO7~TH&MMHtgHibZiSi*- THE PROPER FUNCTION OF
 THE ESTIMATES IS TO HELP LOCAL OFFICIALS SELECT  AND
 EVALUATE ISSUES AND SET PRIORITIES FOR THE TOPICS
 EXAMINED.
2RID'S ESTIMATE OF THE ACTUAL NUMBER OF CANCER  CASES IN
 THE STUDY AREA IN 1984 IS 8,000 CASES.  (SEE II-8 AND
 9.)  THIS NUMBER SHOULD SERVE ONLY AS A POINT  OF
 REFERENCE IN UNDERSTANDING THE RISK ESTIMATES
 PROVIDED.  IN ADDITION, THE RISK ESTIMATES SHOULD
 NOT BE INTERPRETED AS REPRESENTING THE TOTAL UPPER-
 BOUND CANCER RISKS FROM ALL POLLUTANTS IN ANY  PARTICU-
 LAR MEDIUM.  THEY DO NOT TAKE INTO ACCOUNT ALL POLLU-
 TANTS THAT MAY BE PRESENT IN THE MEDIUM, ALL SOURCES
 OF THESE POLLUTANTS, AND ALL EXPOSURE SCENARIOS
 INVOLVING PATHWAYS OR EXPOSURES OF SHORT DURATION TO
 RELATIVELY HIGH DOSES.
*EPA weight-of-evidence classifications:  A = human
 carcinogen; 81 = probable carcinogen.  (See Appendix A
 for more detail.)
*The incidence estimates listed in this column were
 calculated using cancer unit risk factors available in
 1985.
5The incidence estimates listed in this column were
 calculated using current (5/86) unit risk factors.
^Measured cadmium concentrations were below detection
 limits.  For screening purposes only, we calculated
 risks to human health assuming a range in ambient  ,
 concentration from zero to the detection limit.

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                             Table V-1A

         BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS

        UPPER-BOUND ESTIMATES OF LIFETIME INDIVIDUAL CANCER
          RISKS AT SITE OF MAXIMUM AVERAGE CONCENTRATION:
                     METALS IN THE AMBIENT AIR

          PHASE I RESULTS INTENDED FOR DEVELOPMENT OF THE
                      PHASE II RESEARCH AGENDA
    Pollutant
   (weight of
   evidence)

Chromium7 (A)
--All hexavalent
—508 hexavalent
—105 hexavalent
—IS hexavalent
—OK hexavalent.
Cadmium8 (Bl)
       1985
     Analysis
Upper-Bound Lifetime
     Cancer Risk
   (inhalation)1,2

        Revised
    3.6 x 10-4
    1.8 x 10~*
    3.6 x 10-5
    3.6 x 10"6
       0.0
0.0 to 4.6 x 10~6
         19B63
   Exposed
Subpopulation^
       3.6 x 10~*       490,690
       l.B x 10~r       490,690
       3.6 x 10";       490,690
       3.6 x 10~6       490,690
          0.0
    0.0 to 3.6 x 10~6   118,411
JTHE UNIT RISK FACTORS USED IN THIS ANALYSIS ARE BASED ON CONSERVA-
 TIVE ASSUMPTIONS THAT GENERALLY PRODUCE UPPER-BOUND ESTIMATES.
 BECAUSE OF LIMITATIONS IN DATA AND METHODS IN SEVERAL AREAS OF THE
 ANALYSIS, SUCH AS EXPOSURE CALCULATIONS AND POLLUTANT SELECTION,
 RISK ESTIMATES WERE CALCULATED AS AIDS TO POLICY DEVELOPMENT, NOT
 AS PREDICTIONS OF ACTUAL CANCER RISKS IN BALTIMORE.  ACTUAL RISKS
 MAY BE SIGNIFICANTLY LOVER; IN FACT, THEY COULD BE ZERO.  THE
 PROPER FUNCTION OF THE ESTIMATES IS TO HELP LOCAL OFFICIALS SELECT
 AND EVALUATE ISSUES AND SET PRIORITIES FOR THE TOPICS EXAMINED.
'Individual risks calculated using the maximum average concentration
 measured across all monitoring sites.
3EPA weight-of-evidence classifications:  A = human carcinogen;
 Bl = probable carcinogen.  (See Appendix A for more detail.)
*The risk estimates listed in this column were calculated using
 cancer unit risk values available in 1985.
'The risk estimates listed in this column were calculated using
 current (5/86) cancer unit risk values.
^Chromium and cadmium concentrations were the same at more than one
 location.  As a result, the exposed subpopulation is the sum of the
 exposed populations at more than one site.
7Maximum concentration is 0.03 ug/ra3.
^Measured cadmium concentrations were below detection limits.  For
 screening purposes only, we calculated risks to human health assum-
 ing a range in ambient concentration from zero to the upper end of
 the detection limit (about 0.002 ug/m3).

-------
     Noncancer Health Effect

     The ambient  concentration  of  cadmium and  chromium are  well
below the no-effect thresholds for noncancer health effects.
Lead levels are  also well below  the, national ambient air quality
standard.  Because people are exposed to lead in all media, ambient
lead, neverthless, does contribute some, albeit  unclear,  amount to
total lead  exposure.   As   stated  above,  we  did   not  attempt  to
quantify total lead exposures in the Baltimore study area.

Limitations

     As in the analysis of  organics,  there are several limitations
to our  metals risk  assessment that  must   be recognized.   First,
because of data  constraints,  we were  only able to  consider  three
of the four target pollutants.  Zinc does not lead to toxic effects,
except at  very high levels that  we  do not  expect to find  in the
Baltimore area.  Second, we must emphasize  again that the results
presented in this section are for setting priorities only;  they are
not necessarily indicative of the total risks posed by all metals
in the environment.

     Third, the metal ambient data, and thus our risk calculations,
may not be representative of  actual  exposures throughout the study
area.  Finally,  it  is improbable  that  the monitors were  situated
at the  sites  of  maximum  ambient  concentrations  in the  Baltimore
metropolitan area;  therefore,  our  estimates  of  lifetime risk to
the MEI may be understated.

INDOOR AIR POLLUTION

     Recent studies have shown  that  indoor  concentrations of many
substances in non-occupational  settings particularly VOCs,  may be
significantly higher  than  those found  in  the  ambient  air.    As a
result, the  Technical  Advisory  Committee  expressed  interest  in
better understanding  the  risks from  indoor air pollution and the
potential sources  of these  exposures.   We  gathered and  reviewed
all available  concentration data  from  national studies  on  indoor
air pollution.   We  did  not  locate   any  studies  specific  to the
Baltimore area;  however,  some  of  the  results from these studies
are generalizable  to the  Baltimore area.   We used  collective ex-
pertise and  judgement in estimating  the importance of  this  issue
and whether it should be studied in Phase  II.  This approach serves
only to provide a  rough  indication of whether indoor air pollution
could be a problem in Baltimore.   It cannot tell us what the actual
magnitude of the risk is in the  Baltimore  area.   Our findings  from
this effort are summarized below.
                                V-19

-------
 Pollutants

      For the  purpose  of  our  analysis,   we  concentrated on   12
 compounds that  were  detected by  recent  studies  of  indoor  air
 pollution elsewhere in the nation.  These substances were:

      o  Radon

      o  Asbestos

      o  Formaldehyde

      o  Benzene

      o  Chloroform

      o  Tobacco smoke

      o  Products of incomplete combustion (PICs)

      o  1,1,1-Trichloroethane (methyl  chloroform)

      o  Perchloroethylene

      o  Carbon tetrachloride

      o  Trichloroethylene

      o  Chlordane

• Sources

      Table V-15 lists the major  sources and health  effects'  asso-
ciated with indoor air  concentrations  of the 12 target compounds.
 There is also evidence  indicating that  volatilization  from showers
 may be a  source  of chloroform in  the  home.   Chloroform and  other
 trihalomethanes are commonly found  in  most drinking water  supplies.
 Trihalomethanes are a by-product  of the water disinfection  process.
 We discuss the risks  from trihalomethanes  in drinking  water in  the
 next section.

 Preliminary Screening Analysis
 Using National Data

      Cancer

      Our review of existing studies on  indoor air  pollution indic-
 cated to us that  indoor air pollution  could also  be  a problem in
 the Baltimore  area.  We used the risk estimates for tobaccco  smoke
 and radon directly from the  referenced  reports and  refer the reader
 to these documents for a more thorough  discussion of the risk  esti-
 mation techniques employed  in these analyses.
                                V-20

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        Compound
Radon


Asbestos




Formaldehyde
Benzene
Chloroform
Products of incomplete
combustion (NO , CO,
S02, hydrocarbons, hyd.
cyanide)

Tobacco smoke (PIC)
(arsenic, nicotine,
benzene, NOX, CO,
hydrocarbons, reapirable
particles)
1,1,1-Trichloroethane
Perchloroethylene
Carbon Tetrachloride
Trichloroethylene
Chlordane (pesticide)
                                                 Table V-15

                              BALTIMORE  IEMP  PRELIMINARY RISK SCREENING RESULTS

                           POLLUTANTS, SOURCES, AND HEALTH EFFECTS ASSOCIATED WITH
                                  INDOOR AIR  POLLUTION FROM NATIONAL STUDIES
                Source

Soil gas, building materials,  well
water

Insulation and speckling compounds,
building materials (roofing and floor-
ing products)
Building materials (particleboard,
plywood, paneling), UFFI (urea-
formaldehyde foam insulation),  furnish-
ings (furniture, carpets, draperies),
fueled appliances (gas stoves,  ovens,
end unvented space heaters), consumer
products (room deodorizers, paper
products), tobacco smoke

Cleaning solvent, lacquer and cement
solvents, paint remover
Solvent, aerosol propellent
Gas stoves, kerosene heaters, unvented
gas heaters
Smokers
                           Cleaning and degreasing solvent,
                           furniture polish, drain cleaners
                           Dry cleaner solvent, cleaning and
                           degreasing solvent, fabric scouring
                           solvent
Cleaning and degreasing solvent,
pesticide ingredient
Cleaning and degreasing solvent, fabric
scouring solvent
Terniticide
            Health Effects
Lung cancer
Lung cancer, meaoethelioma (rare
cancer), gastrointestinal tract cancer,
asbestosis (fatal scarring of lung),
variety of neoplaatic diseases

Suspect carcinogen, headaches, nausea,
dizziness, tearing and eye irritation,
lower respiratory irritation, pulmonary
edema, possible effect on central
nervous system (CNS)
Carcinogen (particularly leukemia),
blood and bone marrow disorders, CNS
disorders, chromosomal, aberrations

Suspect carcinogen, fetal developmental
effects, liver toxicity, fatigue

Respiratory illness, systemic toxicity
Lung cancer; oral cancer;  larynx and
esophagus cancer; lower  respiratory
illnesses; eye, nose, and  throat irri-
tation; changes in heart rate,  systolic
blood pressure, psychomotor  functions,
small airway disfunctions
                                           Suspect carcinogen; mutagen; death;
                                           cardiovascular effect; eye, nose, and
                                           throat irritation; nausea; light-
                                           headedness

                                           Suspect carcinogen, death, CNS depres-
                                           sant, liver and kidney effects, cardio-
                                           vascular effects, dizziness, headaches,
                                           fatigue
 Suspect  carcinogen,  death,  cardio-
 vascular and respiratory effects, liver
 and kidney effects,  headaches

 Suspect  carcinogen,  death,  CNS depres-
 sant,  decreased psychomotor function,
 •headaches, fatigue

 Suspect  carcinogen,  CNS disorders, toxi
 buildup  in body tissues (liver, kidney,
 and adipose tissue)
Note:  Some of the health effects information is based on experimental animal studies.

-------
 For the other compounds, we used professional judgement in  evalua-
 ting evaluating whether the reported measured indoor concentrations
 could pose a health problem  should they  also be at similar.con-
 centrations in homes in  the Baltimore area.

      All concentration values for these  compounds are  averages,
 with the exception  of formaldehyde.   The  range in formaldehyde
 concentrations represents  typical levels  measured in  residences
 throughout the country.  Again, we must  emphasize that  the  concen-
 tration data used in this  analysis were based on national  studies
 and are not specific to  the Baltimore area.

 It is important to note  that EPA's current policy does not regard
 1,1,1-trichloroethane (TCA)  as a human carcinogen.  EPA previously
 considered TCA a  possible  carcinogen,  but  has  suspended  that
 classification pending a key study currently under review.  Because
 of the uncertainty surrounding TCA, and  the ongoing debate over its
 carcinogenicity,  we  have included TCA as a carcinogen for the  pur-
 poses of sensitivity analysis only.

      Based on  limited  U.S.   data,  EPA's  office  of  Radiation
 Programs also believes  that perhaps  a  million homes  throughout
 the country could exceed  an upper-bound estimate of  3 to 4  in
 100 lifetime risk from exposure  to radon.  Homes in Pennsylvania,
 especially the Reading Prong area, have been observed  with radon
 concentrations as high  as 15  WL (working  levels, the unit  of
 measure for radon decay products),  or  about  a 70  to 90  in  100
 lifetime cancer risk.5

      While we were  unable  to locate  information on radon levels
 specific to Baltimore, radon exposures  could be a  concern within
 'the study area.  As- indicated in Table V-15,  radium in soil  and
 rock is a. major  source of  exposure.   Radon  flows  through  the
-soil and enters homes through  cracks or  openings in  foundation
 floors  or walls.   Additional  research is needed  to better  charac-
 terize  the potential for  radon  exposures  in  the Baltimore study
 area.

      The upper-bound  estimate   of  average   lifetime   individual
 cancer  risks  from  exposure to indoor tobacco  smoke (i.e.,  passive
 smoking)  could also  be as high  as in 1  in 1000 lifetime  cancer
 risk.   The risk estimates  were  based  on a study of lung  cancer
 mortality rates in nonsmoking women with smoking husbands conducted
 by the  National Cancer Center Research Institute in Tokyo.  These
 potential exposures  are  of  concern  to nearly  every  individual
 throughout  the  country,   including  the  Baltimore study area.
 Nearly  everyone has  been exposed to tobacco smoke at  one  time  or
 another.   In  addition, roughly 33 percent of  the adult population
 regularly smokes cigarettes, thus exposing the families, especially
 children,  of  these  individuals  to tobacco  smoke on  a  regular
 basis in the home.6 The data  obtained from  the Total Exposure
                               V-21

-------
Assessment Methodology (TEAM) study  that  EPA conducted  in  Bayonne
and Elizabeth,  New  Jersey during  198i7  indicated that  indoor  air
concentrations of benzene,  chloroform,  1,1,1-trichloroethane,  and
carbon tetrachloride can get quite high relative to outdoor  levels.
While it  is  impossible to  extrapolate directly  from these  city-
specific data to the Baltimore area, one  would  expect  to find some
indoor levels of volatile organic  compounds  in  homes  and buildings
throughout many  areas  of  the country, including  Baltimore.   These
substances are commonly found in  numerous household products,  such
as personal care products, cleaning materials,  paints,  and pesticides.

     Although indoor levels  of  formaldehyde may  not  be a  concern
for all  homes  throughout  the country—for example, the  TEAM  study
did not detect statistically significant concentrations of formald-
ehyde in  any  of the homes  sampled in the 1981 New Jersey  study—
formaldehyde is  released  by  sources  that  could  be found in  various
homes in the Baltimore area.  Formaldehyde is contained  in building
materials  (e.g.,  plywood  and particleboard),  furnishings  (e.g.,
draperies  and carpets), and some  types of  foam insulation containing
formaldehyde resins,  especially  urea  formaldehyde.   Unvented  gas
combustion and tobacco smoking are other  sources of indoor formald-
ehyde .8

     Noncancer

     The data from these  studies suggest  that indoor air concentra-
tions may  under  certain   circumstances   be  high  enough to  cause
increased  concern for  fetal  developmental  effects  from exposures to
benzene and  chloroform.   There  is also  an increased  concern for
liver effects  from  exposure to  indoor  air  concentrations  of TCA.

     There is  also  an   increased  concern  for   noncancer  health
effects  from  indoor exposures to tobacco, and  formaldehyde.   Many
substances in cigarette smoke are  irritants, and nonsmokers exposed
to cigarette  smoke  have  experienced  such symptoms as conjunctival
irritation, nasal discomfort, coughing, sore throats,  and sneezing*
Some studies  have also measured  changes  in heart rates,   systolic
blood .pressure,  and  psychomotor  functions in nonsmokers exposed to
tobacco  smoke.   Finally,  most  studies  have  indicated a  strong
correlation between  reported  respiratory  problems   in children,
especially under two years  of age, and parental smoking.^

     In  the  range   of  typical   formaldehyde   levels  measured  in
selected homes   throughout   the  country   (.01  to  .5  ppm),   there
could also be an increased  concern for noncancer health
effects.   Formaldehyde has  been  shown   in  chamber  studies  with
humans to  be an eye  irritant at concentrations  ranging from  0.1
                                 V-22

-------
to 0.4 ppm.  In addition, some studies have suggested that formald-
ehyde levels of approximately  1 ppm  can  affect  the  central nervous
system, although  the  results  from  these studies are  difficult  to
interpret.10

Limitations

     There are several important  limitations  that must be considered
when interpreting the  results  presented  in  this section.   First,
the indoor air  risk  calculations were based  on data from selected
studies not specific to Baltimore; it is unclear whether these data
on indoor  concentrations  are directly applicable to the Baltimore
area.  Second, our usage of average indoor concentration levels may
not be  representative  of actual  exposure  levels   faced by  many
individuals.  Finally,  there is  equivocal evidence  supporting the
carcinogenicity of TCA.

TRIHALOMETHANES IN DRINKING WATER

     Trihaloraethanes in drinking  water is the final issue of interest
identified by the Human Health Subcommittee.   This section presents
our findings on the risks to human health associated with trihalom-
ethanes (THMs)  in drinking water.   It also  reports the  risks for
other compounds  found  in finished  drinking   water,  specifically
pesticides and heavy  metals.

Pollutants

     We felt that important  insights on the  relative contribution
of trihalomethanes versus  other  pollutants  to human health  risks
could be provided by.looking at THMs, pesticides,  and  metals.  On
the basis of water quality data  for Baltimore's two drinking water
treatment plants,  Ashburton and Montebello, we analyzed the following
pollutants:

     o  Pesticides - Endrin,  Lindane, Methoxychlor,-
        Toxaphene, 2,4-D, 2,4,5-TP

     o  Total trihalomethanes (chloroform)

     o  Heavy Metals - Arsenic, Barium,  Cadmium, Chromium,
        Copper,  Lead,  Mercury,  Silver, and Selenium Sources

Sources

     Most levels  of  pesticides  and herbicides found  in drinking
water are  released - from  nonpoint  sources,  particularly agricul-
tural run-off.   Most  metals  are generally  from background   sour-
ces (i.e., soil),  but  some  may  also be released  from  urban run-
off.   In contrast, trihalomethanes are present  in finished
drinking water  primarily  as  a. by-product of  the  water disinfec-
tion process.  Disinfection of  water is conducted to kill
                                V-23

-------
microbial pathogens  that  can,   if' unchecked,   lead  to  periodic
oubreaks of diseases  such as  cholera or  typhoid.   The  disinfec-
tant, generally chlorine, reacts  with organic matter  in  the  water
to produce trihalomethanes,  particularly chloroform.

Ambient Levels

     Table V-16 presents the  ambient water data  for  the  Ashburton
and Montebello drinking water treatment plants  for the years   1980
through 1983.   We  obtained these data  from the  City  of  Baltimore.
For our assessment  of the exposures associated with   ingestion  of
drinking water, we used an ambient concentration  value that repre-
sented the  mean  of the average  values reported  for  1981 through
1983.  For our analysis of risks, we assumed  that  all trihalomethane
concentrations were  composed of  chloroform  because  past studies
have shown  that chloroform accounts  for the majority of  the triha-
lomethane levels measured.

     Table  V-16 also indicates the Maximum Contaminant Levels (MCLs)
established by EPA for each of  the pollutants listed.   As is clear
from the table, the concentrations  of  all compounds are well within
these standards.   The average trihalomethane  (THM)  level for each
year is  slightly  more than half  of the maximum allowable THM con-
centration.  Nevertheless,  given  our  current  understanding of the
health risks  from exposure to THMs, the present  MCL may  no longer
be deemed protective  of public health.

     It is  important to recognize that concentrations of chloroform,
in particular,  may increase in the  distribution system  over time
even after  the water has left  the  water treatment plant.  This  is
because residual chlorine may continue to react with organic matter
to form more  chloroform.  As  a  result, our risk  calculations based
on average  ambient levels  do  not  capture  the  actual  risks that
some individuals  may   face.  Furthermore,  since  we  only have data
on average  ambient levels,  we can only estimate  lifetime  risks   to
the  average exposed individual.

Exposed Population

     The exposed  population  in our  assessment  of  drinking  water
risks is  the  population  served  by  each   of  the  drinking   water
treatment plants.   The  Montebello  plant  serves a  population   of
approximately  700,000; Ashburton  serves about  900,000  residents.
This includes  all  of  the  population in Baltimore City,  89%   of
the population  in Baltimore  County,  and a  small number  of people
in Anne Arundel County.

Unit Risk Factors

     As  in  the previous  analyses,  we assessed the possible
cancer risks  from  ingestion  of  Baltimore  water,  as  well as  the
                                 V-24

-------
Table V-16
BALTIMORE .IEMP PRELIMINARY RISK SCREENING RESULTS
WATER QUALITY DATA
ASHBURTON TREATMENT PLANT— FINISHED WATER
1980 1981 1982


Pesticides (ug/1)
Endrin
Linda ne
Methoxychlor
Toxaphene
Herbicides (ug/1)
2,4-0
2,4,5-TP
Total trihalomethanes
(TTHM)
Heavy Metals (mg/1)
Arsenic
Barium
Cadmium
Chromium
Copper
Lead
Mercury
Sil ver
Selenium
IMCL = Maximum contaminant
^For all compounds, except
limits.

MCL1

0.2
4.0
100
5.0

100
10

100

0.05
1.0
•Q.01
0.05
0.05
0.05
0.002
0.05
0.01
level
total


Average Range Average

<0.04 . <0.04
<0.01 <0.01
<1.0 <1.0
<1.0 <1.0

<0.5 <0.5
<0.03 <0.03

52

<0.01
0.02
<0.001
<0.001
<0.01
<0.01
< 0.001
<0.001
< 0.005
(EPA Interim Final Drinking
trihalomethanes and barium,


Range Average Range

<0.04
<0.01
<1.0
<1.0

<0.6
<0.03

37-68 55 35-72

<0.01
0.02
<0.001
< 0.001
<0.01
<0.01
<0.001
< 0.001
<0.005
1983

Average









56

0.001
0.03
0.002
<0.001
<0.01
<0.01
<0.001
< 0.001
0.002
Water Standards; source: EPA Primary
pollutant concentrations are reported



Auc
Range 198:

<0.
<0.
<1.
<1.

<0.
<0.

34-79 54

<0.
0.
<0.
<0.
<0.
<0.
<0.
<0.
<0.
Water Rules)
at detection


-------
potential for noncancer health effects from drinking water exposures.
As discussed  above,  we  estimated  cancer and  noncancer risks  for
trihalomethanes assuming that total  concentration were  chloroform.

     Cancer

     Table V-17 lists the upper-bound cancer unit  risk  values (for
ingestion) for the  pollutants  measured  in  the  Baltimore  drinking
water.  In Phase I,  only chloroform was evaluated.  In this section,
however, we  present  the  risks  associated  with  other  compounds
present in drinking water to provide perspective.  The current unit
risk factors  used  for  these substances, as  well  as  the  revised
potency value for chloroform, were all developed by CAG.

     Noncancer

     Table V-18 lists the noncancer health effects for the measured
pollutants in drinking water,  as well as the  no-effect thresholds
for ingestion.  We were able to  obtain these data for  9  of  the 16
compounds.  We were  unable  to assess  risks  from lead  because the
dose-response data for this element are currently undergoing internal
review.  What is clear, however,  is  that low levels  of  exposure to
lead can lead to  adverse  reproductive and  neurological effects in
the unborn and children and hypertension in adults.H

     We were,  however,   able  to  gather  qualitative  information
regarding situations  in which  lead  levels  could  be  above  EPA's
Maximum Contaminant  Levels   (MCL),  which  are  established on the
basis of non-cancer effects.

Preliminary Screening Analysis and
Risk Assessment Results

     Using the  data  described  above,  we  estimated the possible
cancer and noncancer  risks  associated with ingestion of Baltimore
drinking water.  We calculated the upper-bound annual cancer  incid-
ence for each drinking water treatment plant separately.  We perform-
ed these computations by first multiplying the average concentration
for each  pollutant  by  the   appropriate  unit   risk  factor  and the
population served by  the plant.  We then divided by 70 to  derive
our estimate of annual cancer incidence.

     Because of the  availability of  only average  ambient data, we
could only estimate upper-bound lifetime  cancer risks  to the average
exposed individual.  We estimated these  risks by simply multiplying
the average  ambient  concentration  by  the  appropriate  unit  risk
factor.  For  noncancer  health  effects,  we  compared  the average
ambient concentrations with  the no-effect thresholds.   Our specific
findings for  each measure of risk follow.
                                V-25

-------
                               Table V-17

           BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS

                  UPPER-BOUND CANCER UNIT RISK VALUES:
                      POLLUTANTS IN DRINKING WATER
   Pollutant

Chloroform (total
  trihalomethanes)

Barium
  Ingest ion
 »«••«
  1985
Analysis
               Revised
                19862
1.0 x 10-6    2.3 x 10~6
  Grouping
  Based on
EPA Criteria3
    B2
"Current EPA policy does not regard barium as carcinogenic through
 ingest ion.  As a result, we could not perform a risk assessment for
 this compound.
     unit risk factor presented in this column was developed by CAG in
 1984 and used in the preliminary Phase I risk calculations.
2The unit risk factor presented in this column is current as of 5/7/86.
^EPA weight-of-evidence classifications:
 A s human carcinogen; B2 = probable carcinogen; C = possible
 carcinogen.  (See Appendix A for more detail.)

-------
Table V-18
BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS
NONCANCER HEALTH EFFECTS AND. PRESUMED HUMAN THRESHOLDS:
POLLUTANTS IN DRINKING MATER1


Pollutant
Arsenic







Cadmium



Chloroform (total
trihalomethanes )


Chromium +3




Chromium +6

Copper
Lindane



Mercury

Selenium





Toxaphene

Endrin
Methoxychlor
2,4-0
2,4,5-TP
Bariun
Lead2
Cil war
J±l VCF
N.A. = Mot available.


Health Effect
Fetal Developmental
Liver
Neuro behavioral
Vascular Disorder
Hyperpigment and
Keratoses
Chronic Poisoning
Reproductive
Fetal Developmental
Liver
Kidney
Reproductive
Fetal Developmental
Liver
Neurobehavioral
Kidney
Fetal

Liver

Kidney
Fetal Developmental
Reproductive
Dietary Problem
Liver
Neurobehavioral
General Toxicity
Fetal Developmental
Fetal Developmental
Neurobehavioral
Fetal Developmental
Liver
Neurobehavioral
Selenosis
Kidney
Reproductive
Liver
Reproductive


	
	
	
__
—


IT he threshold values presented in this table
2The dose-response 'data
available for our use.
for lead are currently

RID-Derived -
Threshold
(ug/1) - Source
133 Hood et al. 1977
133 Clement-Iron & Steel Study
133 Clement-Iron & Steel Study
133 MHO 1981
Perry et al. 1948; NIOSH 1975
133
1,070 Zaldivar 1977
133 Hood et al. 1977
874 Schroeder & Kitchener 1971
17.5 Friberg 1950
17.5 ADI 1985; Kjellatrom et al. 1977
4,090 Scharpf et al. 1972
795 Thompson et al. 1974
699 Heywood et al. 1979; ADI 1986
117 Challen et al. 1958; USE PA 1985
225 Heywood et al. 1979
35,000 Clement-Iron & Steel Study, Unverified
ADI
35,000 Clement-Iron & Steel Study, Unverified
ADI
35,000 Clement-Iron & Steel Study
170 Gale 1978
170 Gale 1978
149,000 Venugopal et al. 1978
11.0 ADI 1986
11.0 Doc. 4 EPA
11.0 Doc. 4 EPA
11.0 Earl et al. 1973
11.0 EPA 1980
11.0 ADI 1985; EPA 1980
105 Schroeder et al. 1971
105 NAS 1976; EPA 1980
105 Smith et al. 1936; Harr et al. 1967
105 Venugopal & Lucky 1979; ADI 1986
105 Venugopal & Lucky 1979
105 Schroeder & Kitchener 1971; NAS 1976
43.7 NAS 1977
131,000 Deichmann 1972
N.A. 	
N »A» — —
N.A. 	
N.A. 	
M A ^f^t^fn*
N.A. 	
N*
• n« .- _ ^—^
were developed by RID and are current as of 5/7/86.
undergoing internal review and are, therefore, not


-------
     Cancer Incidence

     Table V-19 presents the upper-bound estimates of annual
excess cancer  incidence from  exposure  to  drinking  water  treated
by the  Ashburton  and  Montebello  plants.   Using  the  1985  unit
risk factors,  the  chloroform  ambient   levels  accounted  for  an
upper-bound estimate  of  less than  one   excess annual  cancer  case
from ingestion of either Ashburton or Montebello water.

     Using the  revised  1986 unit  risk   factors  for  chloroform
resulted in  a  revised   upper-bound  estimate  of  annual  cancer
cases of  roughly 2  excess  cancer  cases per  year  for  Ashburton,
and about 1 excess annual cancer cases  for Montebello.
Chloroform  accounts  for  all  of  the  predicted  excess   annual
cancer cases  from  ingestion of the  drinking water  from Ashburton
and Montebello.   No  other  monitored  pollutants  of  carcinogenic
concern were detected.  We have assumed that the actual concentrations
for these were neglible for the purpose of estimating the upper-bound
cancer risk  from drinking  water.   However,  were  these pollutants
pr-esent in the drinking water at  levels equivalent to their respective
levels of detection, they would, in  total, account  for an additional
excess 0.5  cancer  cases  at  Ashburton  and  0.4  cancer cases  for
Montebello beyond those cited above (using  the latest,  and higher,
GAG cancer potency values).

     Please note, however, that only a small number of carcinogenic
compounds were monitored  in the drinking water.   Consequently,  we
cannot rule  out  the possibility  that  we  have  overlooked  other
chemicals posing possible cancer risk.  The  statements  we  make can
only relate to compounds  for which  we have  actual monitoring data.

     Lifetime Cancer Risks to the Average Exposed Individual

     Our estimates  of  the  upper-bound  lifetime cancer risks to the
AEI are detailed in Table  V-20.  The Phase I  calculations  show an
upper-bound lifetime  cancer  risk  to the  AEI  from  chloroform  in
drinking water  of  roughly   5  chances  in  100,000 at  each  of the
drinking water  treatment  plants  (Ashburton and  Montebello).   The
revised unit risk factor (1986) for chloroform increased these risk
estimates to  approximately  10 chance in 100,000  from  ingestion of
drinking water at each of the two drinking water  treatment facilities.
Neglible risk is attributed  to  the other chemicals monitored in the
drinking water.   As stated  above,  our  statements  regarding  risk
apply only  to those compounds  for  which we have  monitoring' data.
We also must  emphasize that  chloroform  ambient levels  at  each of
these  plants are well within the MCL.

     Because this  is  a  screening  exercise designed  to  identify
issues of potential  concern, we have also  estimated the risk from
these monitored chemicals should they be present at their respective
levels of detection.  The upper-bound lifetime cancer
risks to  the AEI for the remaining  compounds  ranges from a low of
about 3  chances in 10 million  for lindane to a high of more than  3
chances in  10,000 for toxaphene at each treatment  plant.  Cumulative


                            V-26

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                                                  Table V-19


                               BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS


                           UPPER-BOUND ESTIMATES OF ANNUAL EXCESS CANCER INCIDENCE:
                                    POLLUTANTS IN BALTIMORE DRINKING-WATER1,2


                                PHASE I RESULTS INTENDED FOR DEVELOPMENT OF THE
                                           PHASE II RESEARCH AGENDA



                                     Ashburton3                                    Montebello3
                                         Upper-Bound Annual                             Upper-Bound Annual
                                             Cancer Cases                                   Cancer Cases
    Pollutant            Average	         Average       	
   (weight of         Concentration       1985        Revised        Concentration       1985       Revised
    evidence)4           (ug/1)5        Analysis6      19B67            (ug/1)5        Analysis6     1986 '

ChloroformS (B2)          54.3            0.7          1.6               49.3            0.5          1.1


  Total                                   0.7          1.6                               0.5          1.1
*THE UNIT RISK FACTORS USED IN THIS ANALYSIS ARE BASED ON CONSERVATIVE ASSUMPTIONS THAT GENERALLY PRODUCE
 UPPER-BOUND ESTIMATES.  BECAUSE OF LIMITATIONS IN DATA AND METHODS IN SEVERAL AREAS OF THE ANALYSIS, SUCH  AS
 EXPOSURE CALCULATIONS AND POLLUTANT SELECTION, RISK ESTIMATES WERE CALCULATED AS AIDS TO POLICY DEVELOPMENT,
 NOT AS PREDICTIONS OF ACTUAL CANCER RISKS IN BALTIMORE.  ACTUAL RISKS MAY BE SIGNIFICANTLY LOWER;  IN FACT,
 THEY COULD BE ZERO.  THE PROPER FUNCTION OF THE ESTIMATES IS TO HELP LOCAL OFFICIALS SELECT AND EVALUATE
 ISSUES AND SET PRIORITIES FOR THE TOPICS EXAMINED.
2RID'S ESTIMATE OF THE ACTUAL NUMBER OF CANCER CASES IN THE STUDY AREA IN 1984 IS 8,000 CASES.  (SEE  II-8 AND
 9.)  THIS NUMBER SHOULD SERVE ONLY AS A POINT OF REFERENCE IN UNDERSTANDING THE RISK ESTIMATES PROVIDED.   IN
 ADDITION, THE RISK ESTIMATES SHOULD NOT BE INTERPRETED AS REPRESENTING THE TOTAL UPPER-BOUND CANCER  RISKS  FROM
 ALL POLLUTANTS IN ANY PARTICULAR MEDIUM.  THEY DO NOT TAKE INTO ACCOUNT ALL POLLUTANTS THAT MAY BE PRESENT IN
 THE MEDIUM, ALL SOURCES OF THESE POLLUTANTS, AND ALL EXPOSURE SCENARIOS INVOLVING PATHWAYS OR EXPOSURES OF
 SHORT DURATION TO RELATIVELY HIGH DOSES.
^Ashburton serves a population of 900,000; Montebello serves a population of 700,000.
*EPA weight-of-evidence classification:  B2 = probable carcinogen.  (See Appendix A  for more detail.)
^Measure of .pollutant concentration in finished water over 1981-1983, City of Baltimore Drinking Water  Quality
 Data (Versar, 1984).
^Chloroform risk calculation based on the unit risk factor available  in 1985.
'Chloroform risk calculation based on the most current unit risk factor (5/7/86).
^Analysis assumes total trihalomethane concentration is chloroform.

-------
                                    Table V-20

                BALTIMORE EMP PRELIMINARY RISK SCREENING RESULTS

                UPPER-BOUND ESTIMATES OF LIFETIME CANCER RISKS TO
                         THE AVERAGE EXPOSED INDIVIDUAL:
                     POLLUTANTS IN BALTIMORE DRINKING MATER1

                 PHASE I RESULTS INTENDED FOR DEVELOPMENT OF THE
                             PHASE II RESEARCH AGENDA


                               Ashburton                     Montebello
                           Upper-Bound Risks             Upper-Bound Risks
                              to the AEI2                   to the AEI2
      Pollutant            1985         Revised
(weight of evidence)3    Analysis4  j     19865

Chloroform6 (B2)         5.A x 10"5    1.2 x 10~4
4.9 x 10~5    1.1 x 10~*
XTHE UNIT RISK FACTORS USED IN THIS ANALYSIS ARE BASED ON CONSERVATIVE ASSUMPTIONS
 THAT GENERALLY PRODUCE UPPER-BOUND ESTIMATES.  BECAUSE OF LIMITATIONS IN DATA AND
 METHODS IN SEVERAL AREAS OF THE ANALYSIS, SUCH AS EXPOSURE CALCULATIONS AND
 POLLUTANT SELECTION, RISK ESTIMATES WERE CALCULATED AS AIDS TO POLICY DEVELOP-
 MENT, NOT AS PREDICTIONS OF ACTUAL CANCER RISKS IN BALTIMORE.  ACTUAL RISKS MAY
 BE SIGNIFICANTLY LOWER; IN FACT, THEY COULD BE ZERO.  THE PROPER FUNCTION OF THE
 ESTIMATES IS TO HELP LOCAL OFFICIALS SELECT AND EVALUATE ISSUES AND SET PRIORI-
 TIES FOR THE TOPICS EXAMIhCD.
^City of Baltimore Drinking Water Quality Data (Versar, 1984) provided the average
 pollutant concentration in finished water.
5EPA weight-of-evidence classification:  B2 = probable carcinogen.  (See
 Appendix A for more detail.)
\)nit risk factor utilized in risk calculation Mas developed in 1985.'
^Unit risk factor utilized in risk calculation is current as of 5/7/86.
^Analysis assumes total trihalomethane concentration is chloroform.

-------
upper-bound lifetime risks to the AEI for these other compounds  are
close to  4 chances  in  10>000   from - ingest ion of  Ashburton  and
Montebello water separately.


     Noncancer Effects

     The average ambient concentrations of the pollutants considered
in drinking water  at  the  distribution  plants  are  well below  the
no-effect  thresholds  for noncancer  health  effects.   However,  a
more  definitive analysis  of noncancer  effects could  be  performed
if we  used data  showing  the  range of  pollutant  concentrations
throughout the drinking water distribution system.   We did not have
these data for this analysis.

     Nevertheless, a  qualitative assessment  of the potential  for
contamination of drinking  water from lead  solder  and  flux  in  the
distribution system  indicated that,  in  areas of corrosive  ground
water, lead may occur  at levels  in excess of the 50 ug/1 MCL estab-
lished by  the  EPA.12  Studies  by Carroll and  Montgomery  Counties
showed that  new  plumbing,   either  alone  or   in  combination  with
corrosive water, may  also  cause lead levels  well in excess  of  the
drinking water standard.I3   In  Carroll County,  78  out of 350 (22%)
of random  samples  of  tap  water taken  in the  early  morning  showed
levels above  50  ug/1.  Five  percent of  the  samples were above
the drinking  water  standard  when water  was  in normal  daily use.
Levels ranged up to 500 ug/1.1^

Limitations

     There are  three  major   limitations  to  our analysis  of  the
risks from ingestion of drinking water.  The first area  of uncertain-
ty results  from our usage of  average  ambient data.   As emphasized
in our preceding discussions, average values do not permit a thorough
assessment of the range  of potential concentrations  to which indiv-
iduals are  exposed.    They also do  not  permit an analysis  of  the
risks to  the  most  exposed  individual  or  the increased  risks of
noncancer health  effects.   For  example,   average   drinking water
values measured at the treatment plant may not  be representative of
ambient levels of chloroform  in  people's tap water because chloroform
can continue to be formed  in the distribution system.

     The second area of uncertainty in our analysis is the assumption
that total  trihalomethane levels  are entirely due  to chloroform.
While chloroform  is  often found in drinking  water,  other  trihalom-
ethanes, such  as  dichlorobromomethane,   chlorodibromomethane,  and
bromoforra can also  be present  in  finished  drinking water.   If the
potency of  these  compound is less than that  for chloroform  we  have
overstated the  risks  from trihalomethanes in  drinking water.   On
                                V-27

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the other hand, if the toxicity of these substances is greater than
that for  chloroform,  we  may haye  underestimated  the  total  risks
posed by drinking water.

     The final  limitation relates to  the  relatively  small  number
of substances  for  which  we  have monitoring data.   Our statements
regarding risk  can apply  only  to those chemicals.   Nevertheless,
our inability to detect the substances, other than the trihalometh-
anes, that  are the most  likely  chemicals  to  contaminate drinking
water (should  it  become  contaminated)  supports us  in our  belief
that we have not overlooked the most important risks.

RISK COMPARISONS

     Having presented separately  our findings for the four  issues
of interest,  it will be  useful  to  summarize and compare the risk
data by pollutant and route of exposure for three of these specific
to Baltimore  (the  estimated  indoor  air risks  were  based on data
from other cities throughout the country and are not representative
of the  Baltimore  area).   We have  compiled summary  tables for the
three measures  of risk  considered:   aggregate cancer  incidence;
lifetime individual cancer  risks;  and  the potential  for  noncancer
effects.  Such  comparisons provided guidance in developing targeted
research agendas for Phase II.

Baltimore Risk  Comparison

     Cancer Incidence

     Table V-21 presents our upper-bound estimates of annual cancer
incidence for the  Phase  II priority issues using the  most current
unit risk  factors.   It  is  difficult to compare the  cancer  risks
from exposures  to  ambient air  and drinking  water  because  of the
uncertainty surrounding the chromium risk  estimates.   If  we  assume
that there  is  no  hexavalent chromium,  the excess  cancer  incidence
from air  and  drinking  water  exposures is   somewhat   similar  (an
upper-bound estimate of roughly 3 excess annual cases in air  versus
an upper-bound  estimate  of  almost 3 excess annual cancer cases in
drinking water).  However, if we  assume that total  chromium levels
are composed  entirely of hexavalent  chromium,  the  cancer  risks
associated with air  toxics  is  more  thanx twice  the  cancer  risks
from ingestion  of contaminated drinking water.

     From the   standpoint  of  pollutant  contribution,  there  are
several interesting  observations.   Of  the  pollutants studies  in
air,  the pollutants of  greatest concern are  chromium and benzene.
Second,  of  the substances  examined  in Baltimore   area  (surface)
drinking water,  only  chloroform  (THMs)  posed  potential  risks.
Third,  while no single pollutant dominates  both routes of exposure,
chloroform appears to be relatively  significant for air and drinking
                                V-28

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                         Table  V-21

      BALTIMORE IEMP PRELIMINARY  RISK  SCREENING RESULTS1,2

       COMPARISON OF UPPER-BOUND  EXCESS" ANNUAL CANCER
     INCIDENCE ACROSS ISSUES AND  POLLUTANTS IN BALTIMORE

       PHASE I RESULTS INTENDED FOR  DEVELOPMENT OF THE
                  PHASE II RESEARCH  AGENDA

                       (1986 analysis)

                                                     Drinking
Compound (weight of evidence)^        Air              Water

Volatile Organic
Compounds

Benzene (A)                           1.80
Trichloroethylene (B2)                0.02
Perchloroethylene (B2)                0.10
l,2-Dichloroethane(B2)                0.10
Chloroform (B2)                       0.40              2.7
Carbon Tetrachloride (B2)             0.30
1,2-Oichloropropane (C)               0.10              ' -

                                      2.82              2.7
Chromium (hexavalent)4 (A)         0.00 to 4.2
Cadmium5 (Bl)                      0.00 to 0.04
  Subtotal                         0.00 to 4.24

TOTAL6                              2.8 to 7.1          2.7
XTHE UNIT RISK FACTORS USED IN THIS ANALYSIS ARE BASED ON
 CONSERVATIVE ASSUMPTIONS THAT GENERALLY PRODUCE UPPER-BOUND
 ESTIMATES.  BECAUSE OF LIMITATIONS IN DATA AND METHODS  IN
 SEVERAL AREAS OF THE ANALYSIS, SUCH AS EXPOSURE CALCULATIONS
 AND POLLUTANT SELECTION, RISK ESTIMATES WERE CALCULATED AS
 AIDS TO POLICY DEVELOPMENT, NOT AS PREDICTIONS OF  ACTUAL
.CANCER RISKS IN BALTIMORE.  ACTUAL RISKS MAY BE SIGNIFICANTS
 LOWER; IN FACT, THEY COULD BE ZERO.  THE PROPER FUNCTION OF
 THE ESTIMATES IS TO HELP LOCAL OFFICIALS SELECT AND EVALUATE
 ISSUES AND SET PRIORITIES FOR THE TOPICS EXAMINED.
2RID'S ESTIMATE OF  THE ACTUAL NUMBER OF CANCER CASES IN  THE
 STUDY AREA IN 1984 IS 8,000 CASES.  (SEE  II-8 AND  9.)   THIS
 NUMBER SHOULD SERVE ONLY AS A POINT OF REFERENCE  IN UNDER-
 STANDING THE RISK  ESTIMATES PROVIDED.  IN ADDITION, THE RISK
 ESTIMATES SHOULD NOT BE INTERPRETED AS REPRESENTING THE TOTA
 UPPER-BOUND CANCER RISKS FROM ALL POLLUTANTS  IN ANY PARTICU-
 LAR MEDIUM.  THEY  DO NOT TAKE INTO ACCOUNT ALL POLLUTANTS
 THAT MAY BE PRESENT IN THE MEDIUM, ALL SOURCES OF  THESE
 POLLUTANTS, AND ALL EXPOSURE SCENARIOS INVOLVING  PATHWAYS  OR
 EXPOSURES OF SHORT DURATION TO RELATIVELY HIGH DOSES.
%PA weight-of-evidence classifications:  A = human carcino-
 gen; Bl, 82 = probable carcinogen; C  = possible carcinogen.
 (See Appendix A for more detail.)
^Chromium incidence calculations  indicate a range  of possible
 ambient levels of  hexavalent chromium  from 0 percent to
 100 percent.
'Cadmium incidence  calculations indicate  a range of possible
 ambient levels  from 0.0 ug/ra3 to  detection  limits  (between
  .001 and  .002 ug/ra3).
^Numbers have been  rounded  to one  significant  decimal.

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water.  It accounts  for  all of the estimated excess  annual  cancer
incidence from those pollutants analyzed in drinking water.   In the
ambient air,  it  accounts for  roughly  14 percent of  the  estimated
incidence for the subset of organics studied.

     Lifetime Cancer Risks

     Our summary  of  the  highest upper-bound lifetime  cancer  risks
for the priority issues  is shown  in Table  V-22.   The  increased
upper-bound lifetime cancer risks to the average exposed individual
for drinking water (chloroform) are  estimated to be over 100 chances
(110 for  Montebello and  120  for  Ashburton)  in a million.   The
exposed population is roughly 1.6 million.  In air,  the upper-bound
lifetime cancer  risks  for the maximally  exposed  individual  for
benzene and chloroform are both around  100 chances in a  million.
(100 for  benzene and  110  for  chloroform; whoever,  the  exposed
subpopulation is  relatively  small  compared  with  drinking  water
(roughly 1.6 million in drinking water compared to less than 50,000
for any one chemical  in the  ambient air).  The increased upper-bound
lifetime cancer  risks  for chromium in  the ambient air range  from
negligible (0  percent  hexavalent  chromium) to  360  chances  in  a
million (100 percent  hexavalent chromium).  The exposed subpopulation
for metals is  larger than  for  organics,  approximately 0.5  million.

     Noncancer

     Finally, Table  V-23  summarizes our  findings on  the  increased
potential for  noncancer  health effects  from organics  through  the
different routes  of  exposure  considered  in Baltimore.   The results
from our  analysis suggest  that noncancer  health  effects  are  of
concern for exposures to  organics  in  the ambient air.   The ambient
levels of the  metals evaluated, cadmium and chromium, were  below
the no-effect thresholds.   Similarly,  the pollutant concentrations
in drinking water monitored at  the  distributions points were below
the estimated no-effect thresholds  for ingestion.

     Of the pollutants  evaluated,   only  two  substances appear  to
present an increased  risk  of  noncancer effects  at  their  measured
levels:  benzene  and chloroform.    Benzene  and  chloroform  concen-
trations present  an  increased risk of  fetal developmental effects
from ambient air.  We estimated the exposed subpopulation  by gathe-
ring birth rate  statistics  in  the  study area.   In 1984, there were
27,426 births; the total number of fetuses that  were at  risk  is
unknown.  These  same pollutants were not found  to  be  a problem in
drinking water.

     Lead, because of  its ubiquity in  the  urban environment,  must
be discussed  separately  from  the  other  metals.   Lead is  present
in the  ambient  air,  drinking  water,  street  and  household  dust,
and food.   The  extent to which any  single  route contributes  to
total exposure  in the  Baltimore  area  has yet  to be  evaluated,
but it is  clear that all routes must  be  considered  in  assessing
                                V-29
    in	I1

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                                          Table  V-22

                     BALTIMORE IEMP PRELIMINARY  RISK AND SCREENING RESULTS

                COMPARISON OF UPPER-BOUND LIFETIME  CANCER RISKS IN BALTIMORE1,2

                        PHASE I RESULTS  INTENDED FOR DEVELOPMENT OF THE
                                   PHASE II RESEARCH AGENDA
                                        (1986 Analysis)
                                          Ambient Air
                                        Drinking Water
Compound (weight of evidence)

Volatile Organic Compounds

Benzene (A)
Trichloroethylene (B2)
Perchloroethylene (82)
1,2-Dichloroethane (B2)
Chloroform (B2)

Carbon Tetrachloride (B2)
1,2-Dichloropropane (C)

Metals

Chromium (hexavalent)' (A)
Cadmium6 (Bl)
  Increased
Lifetime Risk
  (chances
in a million)
     100
       5
       5
      68
     110

      21
      36
   0 to  360
   0 to  4
  Exposed
Population
  48,771
  48,771
  14,270
  12,880
  23,997

  23,997
  16,848
 490,690
 118,000
  Increased
Lifetime Risk
  (chances
in a million)
  Exposed
Population
 110  (Montebello)
 120  (Ashburton)
   700,000
   900,000
1THE UNIT RISK FACTORS USED IN THIS ANALYSIS ARE BASED ON CONSERVATIVE ASSUMPTIONS THAT
 GENERALLY PRODUCE UPPER-BOUND ESTIMATES.  BECAUSE OF LIMITATIONS IN DATA AND METHODS IN
 SEVERAL AREAS OF THE ANALYSIS, SUCH AS EXPOSURE CALCULATIONS AND POLLUTANT SELECTION, RISK
 ESTIMATES WERE CALCULATED AS AIDS TO POLICY DEVELOPMENT, NOT AS PREDICTIONS OF ACTUAL CANCER
 RISKS IN BALTIMORE.  ACTUAL RISKS MAY BE SIGNIFICANTLY LOWER; IN FACT, THEY COULD BE ZERO.
 THE PROPER FUNCTION OF THE ESTIMATES IS TO HELP LOCAL OFFICIALS SELECT AND EVALUATE ISSUES AND
 SET PRIORITIES FOR THE TOPICS EXAMINED.
2Riska in ambient air are presented as upper-bound individual lifetime cancer risks at the site
 of maximum average concentration (not a true MEI risk calculation); risks in drinking water
 are presented as cancer risks to the average exposed individual.  Risks from indoor air are
 also presented primarily as cancer risks to the average exposed individual, but are not .based
 on data specific to Baltimore.
3EPA weight-of-evidence classifications:  A = human carcinogen; Bl, B2 = probable carcinogen;
 C s possible carcinogen.  (See Appendix A for more detail.)
*The exposed population is in the grid at the monitoring site of maximum concentration.
^Chromium risk calculations indicate a range of possible ambient levels of hexavalent chromium,
 0 percent to 100 percent.
 Cadmium risk calculations indicate a range of possible ambient levels from 0.0 ug/m  to the
 upper end of the detection limit (about  .002 ug/m5).

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                                         Table V-23

                     BALTIMORE IE HP PRELIMINARY RISK SCREENING RESULTS

     POLLUTANTS OF POSSIBLE REGULATORY CONCERN FOR NONCANCER HEALTH EFFECTS IN BALTIMORE


                                                                          Population Expoaed
                                                     Potential             Above No-Effect
      Pollutant           Exposure Pathway        Health Effecta1             Threshold

Benzene                      Ambient air       Fetal developmental                *

Chloroform                   Ambient air       Fetal developmental                "*
*In 1984, there were 27,426 births.  The total number of fetuses that did not come to terra
 is unknown.

iflECAUSE OF SIGNIFICANT UNCERTAINTIES IN THE UNDERLYING DATA AND ASSUMPTIONS, THESE
 ESTIMATES OF THE POPULATIONS POTENTIALLY AT RISK OF DISEASE ARE ONLY ROUGH APPROXIMATIONS.
 THEY ARE BASED ON CONSERVATIVE ESTIMATES OF EXPOSURE AND CHEMICAL TOXICITY.  UNLIKE CANCER
 RISK ESTIMATES IN THIS REPORT, THESE ARE ESTIMATES OF POPULATIONS EXPOSED AT LEVELS THAT
 MAY POSE HEALTH RISK} THEY ARE NOT ESTIMATES OF POSSIBLE NUMBERS OF CASES OR PROBABILITY
 OF DISEASE.

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the importance  of  a particular  medium to  exposure.   In  isolated
circumstances, lead  in  drinking  water  in  residential   plumbing
containing lead  solder  and  flux  has  reached  levels  where  this
pathway of exposure  alone  poses  significant risk to human health.
And there are documented cases of  lead poisoning in children exposed
to lead  in  household  dust—165  hospitalizations  alone  in  1985.

SUMMARY OF RESULTS

     Within  the limitations discussed  throughout this  chapter,  our
analyses have yielded the following results.  The results  have been
useful in focusing Phase II research to help State  and local autho-
rities in the Baltimore area in setting  priorities and in conducting
other activities  associated  with  the  management^ of  environmental
risks.

Exposure Results

     o  Of the organic compounds evaluated in the ambient air,  the
        highest measured concentrations were for benzene,  toluene,
        and  ethyl benzene.

     o  Results from the Baltimore IEMP air toxics monitoring pro-
        gram indicated that there can be significant variation in
        the  concentrations of some organics and metals throughout
        the  Baltimore area. This  is an  important factor to consider
        during Phase  II  when  we  will  explore  control  options.

     o  Indoor air pollutant levels could be higher than ambient
        air  concentrations for the subset of pollutants evaluated
        in the Baltimore IEMP.   In  some instances,  indoor air con-
        centrations may be ten times higher.

     o  Data on lead in drinking  water  suggest that levels  may be
        be higher than  the drinking water standard for houses with
        the  new plumbing containing lead solder and flux and  corro-
        sive tap water.  Between the time that our Phase  I  analysis
        was  completed and this report was  prepared, the local  plumb-
        ing  boards  voted  to  prohibit  lead  (95%)  solder  and the
        Maryland Legislature acted to ban  lead solder in new plumbing
        and  to  educate  the public on  the  risks.

      Results for Cancer  Risks

      o  Exposure  to  a  subset of  organics  found  in  the  ambient air
        in Baltimore could result in  an upper bound estimate  6T
        roughly 3 excess cancer  cases  a year.   Benzene exposures
        alone account   for  about  two-thirds of  the  total  excess
        cancer  incidence;  perchloroethylene,  chloroform and  carbon
        tetrachloride  together  contribute  nearly  one-third  of  the
        total.  Exposures  to  1,2 dichloropropane,  1,2-dichloroethane,
        and  trichloroethylene  account  for  the  remaining  amount  of
        the  total excess cancer incidence  estimated for the compounds
        studied.


                                 V-30

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   trichloroethylene account ' for  the  remaining amount of  the
   total excess cancer  incidence  estimated for the  compounds
   studied.

o  The estimated upper-bound risks from exposure to chromium
   and cadmium in the ambient air range from roughly O.I  ex-
   cess cancer cases a year to over 4 excess cancer cases a
   year.  This  range representsdifferingassumptionsabout
   regarding the fraction of total chromium that is hexavalent
   (1 percent to 100 percent).   Because no cadmium was actually
   detected in the ambient air, our  risk estimates were  based
   upon the lowest concentration at which  it  can  be detected.
   Even under these  very  conservative  assumptions (protective
   of public health), it contributes very little to total risk
   (0.06 upper-bound cancer cases annually).

o  The estimated upper-bound excess cancer  incidence from in-
   gestion of drinking water could be almost 3 cases per  year
   All of  the estimated   cancer  risks are  attributable  to
   trihalomethanes (chloroform  and related  chemicals).    The
   levels of trihalomethanes are below  the EPA drinking-water
   standard for the substances.

o  Preliminary risk calculations for indoor air using national
   data suggest that exposures to indoor air pollutation  may
   be a relatively significant potential source of risk in the
   Baltimore study area.  The estimated risks for certain
   chemicals could be  ten-fold higher  than those calculated
   from ambient exposures.


Results for Noncancer Risks

o  The preliminary Phase I findings suggest that most of  the
   Baltimore population will be exposed to  chemicals at con-
  .centrations high enough to justify regulatory concern
   Benzene concentrations in the ambient air  may  increase the
   risk of  fetal  developmental effects  throughout  the  study
   area.  (In 1984, there were  27,426 births  in the Baltimore
   area; the  total  number  of   fetuses  at  risk  is  unknown. )
   Similarly,  ambient air  concentrations  of  chloroform  could
   pose an elevated  risk of fetal  developmental  effects,  but
   at only a  select number  of sites  in  the  Baltimore  area.

o  There have been over 150 hospitalizations per year in
   Baltimore of children for lead chelation therapy.   Nearly
   all of the cases  of  high levels of  lead  in the children's
   blood were the result  of  their  exposure to  lead in dust in
   older homes where lead paint  had been used.    To prevent
   future cases of  lead-poisoning  from exposure  to  lead from
   lead paint, the State of Maryland
                           V-31

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        has issued  a  regulation  that  lead  in  contaminated  homes
        must be abated.

Items for Future EPA Consideration

     o  We have a fairly good understanding  of  the  potential  risks
        for several pollutants,  but not the sources  of these pollu-
        tants.  Phase II  data  collection  activities  need to  be
        focused on  better  characterizing  the   sources  of  toxic
        pollutants in  the  Baltimore  area.   This   effort  should
        gather data sufficient  to quantify  pollutant  loadings  by
        source type.

     o  Many of the cancer unit risk factors should be investigated
        further.  The cancer unit risk factors for 1,1,1-
        trichloroethane, formaldehyde,  and arsenic (indestion),
        in particular, have been called into question.

     o  The significance of the risk from chromium depends  upon its
        valence state.   Increased effort  to resolve  the  current
        uncertainty would be useful.
                                 V-32

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1.   While the monitoring program also sampled for methylene
     chloride and 1,1,1-trichloroethane,  the measured data were
     generally found to be unquantifiable.because of
     contamination during transport and handling.


2.   Black & Veatch, Industrial Waste Control Program. Draft
    . Final Report. City of Baltimore, Maryland Bureau of Water
     and Wastewater, April 1984.


3.   A more detailed discussion of the monitoring program can be
     found in the following report:  Versar, Inc., Quality
     Assurance Plan for Monitoring and Analytical Activities to
     evaluate Selected Air Pollutants in Metropolitan Baltimore.
     Maryland.  November 8, 1983.


4.   National Toxicology Program, Technical Report on the
     Carcinocrenicitv Bioassav of 1.2-Dichloropropane  (CAS No."
     78-87-5) in F 344/N Rats and B6C3F1 Mice fGavaae Study). May
     1983, Draft (NIH Publication No. 83-2519).


 5.  Richard Guimond, "Indoor Radon:  Briefing for Lee M.
     Thomas," March 12, 1985, Office of Radiation Programs.


 6.  John D.  Spengler and Ken Sexton, "Indoor Air Pollution:  A
     Public Health Perspective," Science. Vol. 221, No. 4605
     (July 1, 1983), p. 11.
                /

 7.  Memo from L.  Wallace to B. Steigerwald, 10/30/84.
    .Attachment B: Elizabeth-Bayonne, NJ personal exposure;
     pertaining to Total Exposure Assessment Methodology (TEAM)
     Study in New Jersey, 1981.

 8.  Spengler & Sexton, p.12; and J. Repace, Tobacco Smoke, the
     Double Standard, a report from the Center for Philosophy and
     Public Policy, University of Maryland, College .Park, Winter
     1984.

 9.  Spengler and Sexton,  pp. 11-12.

 10. Spengler and Sexton, p. 13.

 11. USEPA, Costs and Benefits of Reducing Lead in Gasoline;
     Final Regulatory Impact Analysis. Chapters IV and V, Feb. 1985.

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12.  Personal Communication  between Hope  Pillsbury,  US  EPA and
     Katherine Farrell,  M.D.,  Maryland OEP, January 1986.

13.  John Love11,  Richard  Isaac,  and Ruth Singer,  M.D.,  Carroll
     County Health Department, Westminster,  Maryland,  Control of
     Lead and Copper in Private Water Supplies, Oct. 18, 1978.

14.  John Love11 et al.

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                CHAPTER VI

ANALYSIS OF SOURCES WITH POTENTIAL ADVERSE
         IMPACTS ON GROUND-WATER

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     CHAPTER VI.   ANALYSIS  OF  SOURCES  WITH  POTENTIAL  ADVERSE
                     IMPACTS ON  GROUND-WATER

     The TAG established a Subcommittee on Ground-Water  Resources
and charged it  with  developing  a  method  for setting priorities
among ground-water issues for  consideration in Phase  II  analyses.
The TAG had developed  a list  of thirty-two  issues  for  study  in
Phase I (see figure IV-2  for  list).  The  subcommittee was speci-
fically asked  to identify  from that  list  no more  than  three
issues that posed  the  greatest  potential  impact on  ground-water
resources.

     This chapter describes the analysis  that the  Subcommittee
conducted.  After providing an  overview  of the  method,  it  de-
scribes the background  of the  members  and summarizes  data  that
were'collected. The next  three  sections describe the scoring  of
ground-water resource impact,  the results  of the scoring,  and the
limitations of the analysis. Finally it presents additional anal-:
yses conducted by the Multi-Media  Metals  Workgroup  which  the TAG
used to help  evaluate  the  recommendations  of the  Ground-Water
Resources Subcommittee.

     The Subcommittee  made  an  initial important  decision:   to
focus on the overall  impact on the  availability  (without treat-
ment) of the ground-water as  a  resource,  rather than to focus on
the expected human health risk  or  ecological  impacts  from conta-
minated ground-water.   Of course,  consideration  of  ground-water
resource impact takes into  account potential  or actual  exposure,
and therefore  risk  to  humans.   Had human  health risk been the
only criterion  however,  the  impacts  from contaminated  ground-
water would have been  neglected in two types of situations.  The
first is  where  ground-water is  not  currently used  for  drinking,
but could be  in the  future;  the  second  is  situations  where the
health risks are abated by  either  treating the water or  finding
alternative sources.

     The Subcommittee  also  identified  economic impact  as an im-
portant aspect  of  ground-water  degradation.  Contaminated ground-
water loses some of  its usefulness to  humans.  When ground-water
that is being used as drinking  water becomes contaminated, it can
be treated to restore its usefulness  or an  alternate supply devel-
oped.  Either  alternative  can  be quite  expensive.    Even  when
groundw.ater that  becomes  contaminated is not  being  used,  the
contamination impairs its usefulness for future needs.

     In summary,  the   Subcommittee  on   Ground-Water"  Resources
decided that it  needed  measures other  than health and  ecological
risk with which to evaluate the importance of ground-water conta-
mination issues.   Furthermore,  it  decided  to focus specifically
on' potential impact to  the ground-water resources.
                               VI-1

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OBJECTIVES

     The TAG  asked  the  Ground-Water  Subcommittee  to  determine
which of  the  32  issues  were  relevant  to ground-water  resource
impact, and  then  rank  them  according  to their  potential  for
causing degraduation  of  ground-water resources.  The  subcommit-
tee first devised  a  "common currency"  for comparing  the severity
of impacts to the  ground-water resource from a diverse  group  of
sources and pollutants.  It was  not  necessary  that the  method  be
absolutely precise  in ranking problems;  after all,  the purpose
of Phase  I of the  Baltimore  study was to  identify a  set of high
priority issues for  further study  in Phase II.  The  subcommittee
recognized that  it  was  necessary,  though,  that the  method  be
flexible enough to allow an  un-biased evaluation of  the diverse
sources for  which  there were  very  different  amounts   of  data.

OVERVIEW OF THE METHODOLOGY

     The Ground-Water  Subcommittee,  composed  primarily  of  local
environmental management  professionals,  developed  an   index  to
evaluate and score different  sources of  ground-water  contamina-
tion according to  the  impact  the source  or pollutant  could have
on ground-water  resources.   These  scores provided  a  relative
ranking for the  sources.  The subcommittee decided to  rely pri-
marily on the judgments  of experts  and  to use an  index because
of the lack of  technical data  necessary to do  more  sophisticated
analysis.  The  subcommittee also«felt that the budget  would not
allow collection of  substantial  amounts of these kinds of  data.
Had more  resources  been  available,  we  could^  have  performed
ground-water modeling and/or monitoring to help us set priorities
among the sources  of contamination.

    o Data needed  for modeling of quantitative effects (like that
      done to assess impacts  on human health)  were not available.
      For many important types of  sources that could contaminate
      ground-water  [e.g., underground storage tanks' (USTs)]» even
      the simplest sort  of information  on number and location of
      facilities did not exist.   For most types of  sources there
      were no data on failure/release/emission rates.  And at the
      time of Phase  I,  there was  no model available  that  could
      integrate source,  'release,  and  hydrogeological  data  to
      yield an estimate of effects.

    o Ground-water monitoring  data were  also  inadequate to com-
      pare problems  from different  source types.   Data existed
      for only a few pollutants.   Monitoring  reports  were fairly
      plentiful  for  some  source  types   (landfills)  while  only
      addressing the  very  worst  cases  for  other  source  types
      (UTS).   New ground-water monitoring efforts would have been
      prohibitively costly.  Because contaminants can  travel  at
                                VI-2

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      widely different rates  in  ground-water this  lack  of  cer-
      tainty would have necessitated- ax vast number  of  monitoring
      wells to characterize the contamination plumes from  diffe-
      rent sorts of point sources.

The Subcommittee thus  developed  an index to  be  applied to  each
source type to determine which kinds of  activities  are likely to
lead to the  greatest adverse  impact  on ground-water  resources.
The index had two basic components  capturing different  aspects of
the effect of a source on ground-water--pollution impact  and  eco-
nomic impact.

     The Subcommittee designed the pollution  impact component as
a very broad measure  of  the volume,  severity, and  general  impor-
tance of ground-water contamination  from different  source  types.
The pollution impact  score reflects  both current impact  from the
sources and potential future dmpact.  It gives higher scores based
on degree of current use of 'the ground-water and  also gives high-
er scores to sources  that  contaminate  ground-water  not currently
used but possibly  needed  in the  future.  This decision reflected
the subcommittee's  value  judgment  that  both   the  present  and
future use of ground-water is  of concern.

The elements comprising the pollution impact score were:

    o number of  individual  units  represented by the  source  type
      (e.g.v/ number of USTs),
    o release volume over time from" each unit,
    o concentration  of  contaminants  in the material  released,
    o persistence of the  released contaminants in the environment,
    o existence of known contamination incidents,
    o potential for future incidents,
    o location of units in vulnerable hydrogeologic environments,
    o size  of  population  using-  ground-water   near  the  units,
    o amount  of  industrial  ground-water   use   near  the  units.

The economic impact component  of the  index was designed to reflect
a different aspect of the impact on ground-water resources.  This
portion of  the  index focused  exclusively  on the  economic costs
that the contamination from that source  was likely to  cause.  In
contrast to the pollution impact score,  the  economic impact score,
rather than weighting all ground-water equally regardless of use,
depends heavily on how the water is currently used, the potential
for contamination  by  source  type,  and how  costly  it  would be to
maintain that use, if contamination occurs. The elements included
in the economic impact score are:

   • o relative  cost  of  programs  to prevent contamination   from
      the source type;                               '
                                  VI-3

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    o relative cost of alternative clean water supplies for
      those ground-water users likely to be affected by contami-
      nation from the source type;

    o relative cost of water treatment for those ground-water
      users likely to be affected by contamination from the
      source type.

     For each source type,  the Subcommittee scored all of these
elements individually and used a weighting.scheme to develop the
pollution score and the economic impact score.  (See "Performing
the scoring of ground-water resource impact".)  The two scores
were then added together to generate a final score.  As a first
cut, pollution and economic impact were weighted equally.  Addi-
tional sensitivity analysis was performed to see if different
weighting schemes would affect the results.  (See "Results of the
ground-water resource impact rankings.")  The higher the final
score, the greater the potential impact on ground-water resources
from the source category.  A more detailed description of the
scoring system is included in the Addendum to this chapter.

BACKGROUND OF MEMBERS OF THE GROUND-WATER SUBCOMMITTEE

     Because the application of the ground-water scoring method
relied so heavily on the judgment of the ground-water subcommit-
tee members, we include a brief outline of the background and
experience that they brought to this task.  Emery Cleaves, the
Subcommittee Chairman, is the Principal Geologist of the Maryland
Geological Survey.  As such, he has many years of experience with
geological issues in Maryland, and special knowledge of local
ground-water contamination incidents.

     The two counties were represented by officials who knew
their counties' ground-water issues intimately.  Colin Thacker
is the Director of Northern Environmental Services in the Balti-
more County Health Department, while N. Singh Dhillon is the
Director of Environmental Health for the Anne Arundel County
Department of Health.

     Representing EPA was Hope Pillsbury who over the last
several years had been directing a major EPA project to assess on
a national basis the comparative risks to ground-water from diffe-
rent source types.  She also had a Master's degree in environmen-
tal studies and a B.S. in geology.

DATA COLLECTION

     The information used for the index and scoring procedure was
a combination of data collected for the project, and, where data
were not available, the judgment and experience of the Subcommit-
                               VI-4

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tee members.  EPA consultants to the Baltimore project prepared
background memoranda on various ground-water issues to summarize
existing data before the scoring process began.  Important con-
clusions from the consultants' memoranda follow.

     Hydrogeology.   Ihe Baltimore study area includes two
geological regions.  The Piedmont area is located in the north-
west portion of the study area and the Coastal Plain is located
in the southeast portion.  (See figure VI-1). As the map shows*
Baltimore County is largely Piedmont geology, and Anne Arundel
County is completely Coastal Plain geology.  The Piedmont terrain
consists of crystalline rocks, including marble, schist, gneiss
and gabbro.  The rocks have low porosity and permeability, with
water moving mainly along joints in the rock.  Ground-water re-
charge occurs locally, and discharge occurs within the same
local watershed.  Consequently any ground-water pollution may be
expected to occur in restricted local areas.

     The terrain of the Coastal Plain consists of unconsolidated
sand, silt, clay, and some gravel.  The sediments occur in con-
tinuous and extensive layers and lenses with aquifers of perme-
able sands and silty sands interdigitated with impermeable silty
clays and clays.  The aquifers dip to the east and south-east
and, unlike the Piedmont, do not mimic surface watersheds.  The
Coastal Plain aquifers have significantly greater porosity and
permeability, and are more vulnerable to contamination. ^'^  On
the other hand, it is easier to get water out of the aquifer and
thus easier to clean up than the Piedment.3

     Water use.  The bulk of the population in the study area is
in Baltimore City where there are few wells and the public system
relies on surface supplies.  About 36% of the households lie in
Baltimore County.  Slightly over 8% of Baltimore County residents
obtain drinking water from private wells, and the remaining peo-
ple obtain drinking water from public systems (which rely primar-
ily on surface water).  Anne Arundel County includes 19% of the
study area population.  Over 99% of these residents rely on
ground-water.  Most industrial ground-water use occurs in the
industrial areas of Baltimore City.

     Landfills.  -There are seven active non-hazardous waste land-
fills, one active hazardous waste landfill, and at least sixteen
inactive landfills in the1 study area.  Landfills contain and re-
lease a variety of pollutants.  Monitoring has detected three
toxic pollutants in ground-water at landfills in the study area.
Chromium has been detected at the hazardous waste landfill at
Hawkins Point.*   Benzene and trichlorethylene have been detec-
ted at the inactive Solley Road landfill.  One portion of this
landfill accepted controlled hazardous substances in the past.
No pollutants have been detected in wells downgradient of the
active non-hazardous waste landfills.  No data were found on
                               VI-5

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/ ( ISK;
y  \   CANONIC

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downgradient water  quality  at  inactive  sites,  other  than  at
Solley Road.^

     There are no  known sites in the  study area where there, is
human exposure to pollutants released in landfill leachate.   How-
ever, leachate release is occurring at all sites that are unlined
and is very likely to occur in the future at sites that are lined.
(In humid climates, virtually all man-made liner systems eventual-
ly will  fail.)   Even so, there is little potential  for exposure
at most  of  the sites for  one  or more of the  following reasons:

     o there are no downgradient drinking water wells;
     o there is an aquitard or hydrogeologic divide that protects
       downgradient wells from contamination^
     o all  active  sites conduct  ground-water monitoring programs
       to detect contamination should it occur.

     Septic tanks.  About  12%  of  the households  in  Baltimore
County and 32% of them  in Anne Arundel County dispose of domestic
wastes in septic tanks; many of these households also use private
wells to supply drinking water.  Septic tanks are not widely used
in Baltimore City.

     In Baltimore  County  both the  Coastal  Plain  and Piedmont
Regions have  experienced   localized  ground-water  contamination
from septic tanks.   The greatest  risk appears to be from the im-
proper disposal  of  chlorinated  solvents,   particularly  in  the
Piedmont because of  the fractured flow.   In a few isolated cases
ground-water  concentrations  of  trichloroethylene   from  septic
tanks have  reached as high as 47 ug/1, but these were the result
of using  underground disposal  facilities  such as  septic tanks
and drywells as  septic  systems as disposal  systems for waste  sol-
vents, both at military installations  and commercial  facilities.^

     In  Anne  Arundel   County,  the   far  eastern  regions  along
Chesapeake Bay  are at  greatest  risk from  septic  tank use.   Al-
though septic  tanks  exist  throughout the  county,  most  of the
areas that  are particularly vulnerable to ground-water  contamina-
tion because  of  poor hydrogeology and/or high  population density
are now  sewered.   However,  in some highly vulnerable  areas locat-
ed south of Annapolis along the  western shore of the Bay, septic
tanks are still  in use  in high densities, and  ground-water conta-
mination has  resulted.   In the Mayo Peninsula area,  nitrate  con-
centrations more than two  times  the drinking  water standard of
10 mg/1  have been  found.7

     A 1978 survey  of  the  Mayo  Peninsula  area  in Anne Arundel
County found  that  about ten percent  of  the drinking water wells
in the peninsula were  contaminated  with fecal  coliform  bacteria
 (i.e.  bacteria  were present).**  The Phase  I  study,  however, did
not  address microbial pathogens  because they are an  acute rather
than a chronic risk.
                                VI-6

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     Surface impoundments.   The only available survey of  surface
impoundments was published in 1980.^  At that time,  there  were 41
facilities in the study area using a total of 89  surface  impound-
ments to handle wastes.  Of the 41 facilities:

     o 2 were agricultural;                    *
     o 4 were municipal;              .         <
     o 35 were  industrial.  Of  these/   11  were  hazardous  waste
       facilities/
     o 15% of the impoundments were lined.

Of the 41 facilities,  37 were located  over  the  sedimentary rock
formations of the Coastal Plain region;  only 4 .were found overly-
ing the fractured flow systems of the Piedmont.  There was little
data on contamination  from these  facilities.  Only  one contamina-
tion incident had  been reported but only two of  the  facilities
had any ground-water monitoring systems  in place.^

     In theory one might expect a moderate likelihood of  contami-
nation from such  facilities.   Only  about 15% of  the impoundments
were lined,  and unlined surface impoundments will recharge ground-
water at  a  very high  rate relative to  other  sources.   However,
the Subcommittee expected  that the  concentration of contaminants
in discharges from  surface impoundments is probably low  relative
to other sources.                                         .
           ''.  ~                   ~-
     None of  the 41  surface  impoundment  sites  were within one
mile (1600 meters) of a downgradient drinking water well.   Prima-
rily because of the low likelihood of surface impoundments affec-
ting drinking water supplies, and the probable rapid discharge to
surface water of  any contaminants  leaking- from  them,  it appears
surface impoundments would not be a major threat to ground-water
resources in the study area is minimal.  Ifl2   Surface impound-
ments could,  however, pollute the Baltimore Harbor and its tribu-
taries.

     Chromium in the area around Baltimore Harbor.   Some  of  the
issues under consideration in  Phase I  related to particular pol-
lutants -vrather than to sources.  Chromium was considered a possi-
ble prevalent ground-water pollutant in the  study area.   Likely
sources of chromium in the area's ground-water include:

    o Chrome  ore  tailings  used  as fill,  material" around  the
      Harbor between  1930  and 1975.   Because the concentration
      of chromium  in  fresh tailings is  quite high and extensive
      leaching is  likely,  elevated concentrations  in  the Harbor
      surface water  and  nearby   ground-waters  would  have  been
      found during  this period  of  time.  The ultimate  environ-
      mental fate of  chromium  in the Harbor is not known.  Moni-
      toring in  the Harbor,  however, showed chromium concentra-
      tions in  sediments  to  be  high,  averaging  435  mg/kg.^
                               VI-7

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    o Landfills at which the tailings have been disposed of since
      1975.  A portion  of the Hawkins Point Landfill  appears to
      have discharged chromium to the subsurface, but  it  is  now
      retrofitted with  a leachate  collection  system.   A  nearby
      hazardous waste landfill has been the most  recent  reposi-
      tory for chrome ore tailings, and it appears not to release
      any leachate into the subsurface.

    o Natural chromium deposits are found in fairly high concent-
      rations in the Baltimore study area.

    o Industrial facilities which have produced  or used chromium
      in large  amounts  may have   chromium  waste  piles  on-site.

We found no  data on  chromium concentrations in  ambient  ground-
water in the  study  area.  -We suspected  that  chromium concentra-
tions might  be  high in  ground-water adjoining the  Harbor area.
But ground-water in this  area is  already seriously degraded,  not
only due to industrial  and wetland fill  activities,  but also due
to saltwater intrusion from the Harbor.^^,11  jn sum, the Subcom-
mittee found no persuasive case for chromium constituting a major
ground-water problem.

     Examination of permits and the literature provided only some
of the information needed to evaluate the likely impact that each
of the source types was causing to ground-water resources.   Addi-
tional information  needed to  score  the  source types  on  the
resource impact  index  came from  the judgment and experience of
the Subcommittee members.

PERFORMING THE SCORING OF GROUND-WATER RESOURCE IMPACT

     The ground-water  Subcommittee used the  rating system
described in the Overview Section to score the issues in terms of
impact on ground-water  resources.   (See  Addendum-to this chapter
for a 'description of the rating system.)   Each Subcommittee member
performed the  ratings  separately,  and   then  each  individual's
ratings on the  different sources  were  combined  to  form a group
rating for each  source  type.  These rankings were then discussed
by the group.   The following section describes how the  scoring
was performed, in particular in relation to the two issues chosen
for further  study:  underground storage  tanks (UST)  and metals.
The sources represented  by the metals  issue,  although  not  'speci-
fied in writing, included  chromium in the harbor  area, landfills
and surface impoundments.

     The first four  elements  of  the pollution impact  score  all
related to source characteristics.  These are:  number of sources,
release volume,  concentration of contaminants, and persistence of
                               VI-8

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contaminants.  USTs  and multi-media metals  tended to  rank high
for these elements.

     The second  two  elements  of - the  pollution  impact  score
related to the present and future rate of contamination incidents.
Generally underground storage tanks were rated high.  Multi-media
metals were rated moderate to high by some members of the Subcom-
mittee..

    - The final three  elements  of the pollution  impact  score are
related to potential extent of impact.   The Subcommittee compared
potential extent of impact for  source types, based on their proxi-
mity to more  vulnerable hydrogeologic  settings  and proximity to
major population or industries using ground-water.

     For instance, farming  ranked medium to high for hydrogeolo-
gic vulnerability,  because much  farming occurs in areas  which
could be hydrogeologically vulnerable.   Sanitary sewer overflows,
however, ranked  low  to medium  for hydrogeological vulnerability
because they  tend  to occur  in the city.   Little or no ground-
water in the  city is  presently  used  for drinking, and it will
probably not  be used   for  drinking in the  foreseeable future.


     USTs and metals tended to rank fairly high  for the  criterion
of proximity  to  major  populations  or  industries  which might be
affected by any ground-water pollution.  This is because they are
likely to be located in areas where ground-water is used by major
centers of population and industry.  This is in  contrast to muni-
cipal landfills, which  in general were rated lower, because they
tend to  be located  in areas  which are not  densely  populated.

     The next score  was the economic  impact score.  Subcommittee
members used  their best professional  judgment  in estimating (1)
the cost to  prevent, or  reduce  contamination,   and  (2)  the cost
of response to  contamination,   either  by providing  an  alternate
supply or treating the  existing supply.

     In examining  the  cost of  programs to prevent contamination
from the source  type, prevention of contamination from  feed lots
was generally ranked low.  Controls are  fairly inexpensive, and
more importantly,  there are not  a lot of  feedlots  in  the study
area.  Prevention of contamination  from underground storage tanks
was generally ranked high because the  Subcommittee believed con-
trols would be very  expensive, particularly since there are many
underground storage tanks.

     The cost  of  alternate   supply  was   generally  ranked  !Low
because it  was   believed  that  contamination incidents  for many
•sources were  more  likely  to  affect  just a  few  private wells
rather than a number of private  wells  or municipal well  fields.
                               VI-9

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 Among the exceptions were .underground storage  tanks./and septic?
 tanks,  which,  because of the  magnitude  of possible leaks and/or
 the widespread distribution  of those  sources,  could cause wide-
 spread impacts to water  supplies.   Therefore the potential cost
 was thought  to be fairly  high.

      The cost  of  treatment was generally related to  the frequency
 and magnitude   of  expected  contamination  incidents.   Farming,
 because of the extent of possible  contamination,  and landfills,
 because of the possible  extent,  magnitude,  and toxic  nature of
 potential contamination, ^tended  to  be ranked higher than some of
 the other sources.   USTs  and   metals  generally   ranked  high.

 RESULTS OF THE RANKINGS
                     '"'•'•
      Each member's score  for  each source was combined in various
•ways to produce an aggregate ranking of issues:

      1. The  first scheme, weighting  pollutant impact and economic
         impact equally,  was  chosen  because it  was the simplest.
         Each person's  pollution  impact (PI)  and economic impact
         (El) scores were added  for  each  issue, and  the scores
         were then added for the  four Subcommittee members.

      2. The  second  approach  weighted pollutiovn  impact twice as
         strongly  as economic  impact.   Some  of the Subcommittee
         members argued that the  ranking  should reflect more con-
         cern for  the ground-water resource itself,  and less con-
         cern for  the economic consequences of  contaminating  it.
         The  (2PI  +  El)  scores  that each individual  gave to an
         issue  were  added for  each  individual to  arrive  at  a
         total  score for each issue.

      3. The  first two  approaches could be strongly  influenced by
         one  or two members of the   subcommittee,  if they have  a
         tendency  to give  most  of the sources  higher  ratings.   The
         choices of these people  therefore would have  a  greater
         chance of being rated  highest.   Therefore,  a third
         approach  was added,  which  involved  counting  the number
         of times  each issue   was  ranked  in  someone's ,3. top five
       ,  issues, whether for pollution or economic  impact reasons.
         This,  we  felt, helped  mitigate the bias that could deve-
         lop  if some members of the Subcommittee gave sources con-
         sistently high or low  ratings.
             V -.   '                                           •*
      Other weighting schemes are possible; for  instance, a system
 where the economic impact is rated twice as heavily  as the pollu-
 tion impact.   We  felt,.however that  these three  schemes provided
 sufficient variety for sensitivity  analysis, especially  because
 the scheme (and its application) relied heavily on best  profes-
 sional judgment.
                                  VI-10

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     Out of the 32  issues,  each subcommittee member scored  only
those which he  or  she judged  to  have ground-water resource  im-
pacts.  If  more than 1 person rated a  certain issue, then  the
issue was included in the  ranking.  The  ranking of each issue was
determined by  averaging  the  scores of  the individual members.
The results of this ranking are presented in Table VI-2.

                             Table VI-2

                           Baltimore IEMP
            Adverse Impacts on Ground-Water Resources
                     Priority-Setting Results

                               P and E                     # of times
Issue                        equal weights      (2P +  E)'   in top fi\

Underground storage tanks        28.4             41.6           4
Multi-media metals              27.1             40.0           3
Benzene                         26.0             39.7           3
Pesticides/herbicides           25.4             37.8           2
Pollution from farming          25.0             35.5           1
Landfills                       24.5             36.0           1
Septic tanks                    22.5             33.3           1
Chromium in Harbor              22.3             32.4           1
Surface Impoundments            19.9             30.3           2
Acid rain                       19.7             27.4           1
Sanitary sewers                 19.4             28.3           1
Road salting                    18.1             28.7           0
Feedlots                        10.0             14.8           0

The Subcommittee  discussed extensively  how  to translate  these
scores into a recommendation to the TAG on the three highest pri-
ority issues.   There was   an  unwillingness  to follow the  index
ranking blindly,  for  several  reasons.   First,  the  aggregate
scores for  some issues masked substantial differences  of  opinion
across the scores by different  individuals.  Pesticides/herbicides
and septic tanks fell into this category; the members  who knew of
or suspected pollution problems  from these sources through their
work experience scored these highest.

     A second reason that discussion was required was that two of
the issues  dealt  with pollutants  rather than  sources, and thus
did not fit neatly into the scoring scheme.  These were scored as
if they were sources.  For instance, multi-media metals encompas-
sed the primary source types releasing metals,  (landfills and sur-
face impoundments) and benzene encompassed primarily  underground
storage tanks.".

     Finally, there was disagreement as to which sources polluted
ground-water at all.  Some members, therefore, scored more issues
                              VI-11

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than others.   Those listed  in  Table VI-2  are the  issues  which
were rated by 50% or more of the participants.

     The Subcommittee  eventually decided  to  recommend only  two
issues for  study in Phase  II  —  underground storage  tanks  and
multi-media metals.  The  general rationale for this was that the
two issues appeared at the top  of  each ranking scheme,  and there
was agreement among all Subcommittee members that they were among
the most important  issues in each  geographic  region of  the study
area.  Thus, the scoring  system served its purpose as a mechani-
sim for expressing technical  views  in  a systemmatic way.   In the
end, however, the scoring system served as an adjunct to.profes-
sional judgement, not as a replacement for it.

     USTs were thought to be particularly important.  Most of the
subcommittee members gave them high  ratings  for  these reasons:

     o the large number of underground storage tanks,
     o the existence of known contamination incidents,
     o the potential for future  incidents,
     o the  size  of the  population  using ground-water near  the
       units, and
     o expected  hiqh  values  for the  three types  of  cost  that
       could be  incurred:   prevention  of  contamination,  treat-
       ment of  contamination,  and  provision  of  an  alternate
       water supply.

     In addition,  the  existence  of  Maryland's  regulations  on
underground storage tanks  increased the importance  of studying
USTs.  Maryland's requirements  to  test tanks by January  of 1987
meant that the rate  of finding  new  leaking tanks  would probably
increase, making further action and knowledge on this issue even
more important than before.

     Metals were of particular  concern  because  of their  persis-
tence once they have been released  into the  environment  and the
large volume of metals in landfills, fill in the harbor, and sur-
face impoundments.

     Benzene problems are closely  related to  USTs,  and chromium
in the Harbor could be included in multi-media metals.  Combining
benzene and USTs, and chromium  and metals further emphasized the
significance of the USTs and metals issues in comparison with the
other ground-water issues.
                                                    r.
     Although agriculture-related  issues  (pesticides/herbicides
and pollution from farming)  received moderately  high scores,  the
Subcommittee did  not   feel   confident  in  recommending them  as
issues for Phase  II study.   Pollution problems associated  with
agriculture are not common to much of the^area.   Also,,  there was
virtually no documented  occurrence  of  pesticides/herbicides  in
ground-water in the region.   This  could be due  to the  fact that


                              VI-12,

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little monitoring for pesticides has been performed.   The Subcom-^
mittee felt  that  USTS and  metals were  clearly more  important,
given the 'demonstrated potential  for ground-water  contamination
and its possible extent.   Also,  the Subcommittee was  unwilling to
recommend any issue  which was not  associated  with at  least  one
tangible contamination event.

LIMITATIONS OF THE ANALYSIS

     1. The  most  critical assumption underlying the work"  of  the
Ground-Water Subcommittee  was that  degradation of  ground-water
resources is an  important concern apart from  and  in addition to
human health and  ecological  impacts.   The Subcommittee  assumed
ground-water contamination  can  have  high  economic  costs  when:

     o the  contamination  affects  an  underground drinking  water
       supply,  necessitating  expense,  either  to treat  the water
       or to obtain a new supply; or

     o the contamination affects ground-water -that is suitable as
       a drinking  water  supply  but is  not currently  used.   In
       this case,  the  contamination has diminished  the  value of
       the ground-water as  a  resource for  meeting  future needs.

     An example of this occurred in the Phoenix area of Baltimore
County.  Solvents were discarded  into several  septic tanks.  The
solvents then  spread  into  the  ground-water,   polluting  several
private wells in the area.   The contamination affected the current
drinking water wells  in the area and the desireability of siting
future wells there.  The remedy that was recommended is to expand
the city drinking  water  system into  this  previously rural area,
though the expansion will come at great expense.

     This concern  for protecting  the ground-water  resource  for
present or future use, rather than merely protecting human health
was a new area for IEMP.   We  found no standard approaches or mod-
els for dealing with  it since EPA has traditionally focused more
on the -health  risks from  ground-water.  The Subcommittee, there-
fore, had to develop  its  own methodology  in  a short  period of
time.  .Their response was  to select a  simple,  straightforward
scoring scheme.                 ,   t                             '
                              -}                                 ' •
     2. The  ground-water  resource impact scoring methodology was
designed as a reasonable approach in the face of missing informa-
tion.  Data  were  extremely  scarce on ground-water quality and on
the extent of contamination in the study area.  Data was slightly
better for  potential  sources of  ground-water  contamination —
their number, location,  and  release  rates.  A moderate but not
intensive effort was  made to  find and orga'nize whatever relevant
data existed.   No new environmental  monitoring or  sampling was
performed.  Where  data were  missing,  judgment,  experience  and
                              VI-13

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 informed  guesswork  were applied ,to  fill the gaps.   These judg-
 ments might well be inaccurate.  Although the scoring method pro-
 duced specific numerical results, these  results lacked precision.
 The  Subcommittee did  not  rely on any  single  set  of results,  but
 instead ranked the  issues  in various plausible  ways and examined
 the  results  to determine  which  source  types  were consistently
 near the  top of the rankings.

     This approach probably would not have uncovered a new or un-
 expectedly important  ground-water issue.  It relied  too much on
 judgment  and experience to yield a result that differed substan-
 tially from  the  Subcommittee  members'  preconceptions.   This is
 not  to denigrate the  scoring system.  It  served  as a systematic
 framework for  organizing  information  so  that  the Subcommittee
 could set priorities  in  an explicit, logical manner.   To uncover
 any  unexpected ground-water  problem,  though,  would have required
 much more new data  such  as  new monitoring  or   modeling  data.

     3. Each of  the  12 factors  (9 under pollution impact  and 3
 under economic  impact) were weighted  equally.    It  is  possible
 that alternative  weightings  could  be  more  accurate.   However
 sensitivity analyses  on the weightings produced the same results.

     4. The  scoring system included elements reflecting each of
 the  multiple factors  that  combine to yield ground-water contami-
 nation, and  resource  impact:  sources,  releases,  fate  and trans-
 port, hydrogeology, exposure  and potential responses.   The scor-
 ing  system combined these  factors  in additive fashion; each ele-
 ment was  scored  and  added to get a total score  for  the source
 type.

     One  might argue  that  the  factors  should be combined instead
 in a multiplicative fashion.   If one of the factors that combine
 to yield  resource  degradation  is  absent  or  particularly benign
 for  a  source type,   then  that  source  type  will  cause  minimal
 resource  impact.    For example,  a  source  type  (landfills)  can
 cause only  minimal resource  impact  if  it  affects ground-water
 only in locations where  the ground-water very rapidly dischargees
 to the bay and thus there is no existing  or potential human use
 of that  ground-water.  A  multiplicative combination  of factors
 (with population use  of ground-water getting scored zero or close
 to it) would give landfills an appropriately low score.  An addi-
 tive approach,  on  the other hand, would not  allow the water use
 score to  dominate.

     The  result of using a multiplicative rather than an additive
approach  in the scoring scheme would  have been to distinguish USTs
 and  metals even  further  from the  other  issues.   USTs and metals
have few  factors  on  which they should  receive particularly low
 scores,  whereas  many   of  the  other   issues  have  more  of  those
 factors.
                              VI-14

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     5. There were  substantial  differences among individuals  in
the scores they assigned on some issues.   This could imply either
a lack of  reliability  in the  scoring approach, ground  rules  for
scoring that were open to misinterpretation,  or simply legitimate
differences of  opinion  among  experts.   The  first  two  possible
explanations represent  criticisms  of  the scoring  process,*  the
third one does not.   In general, the larger differences in scores
tended to arise from differences in the individuals' experiences,
with those more ^highly involved in toxic/industrial  contamination
issues (metals,  surface  impoundments,  landfills,  USTs,  benzene,
chromium) rating  them  higher   and  those  involved  with  rural/
agricultural issues  (farming,   septic  tanks,  pesticides)  rating
those issues higher than the other Subcommittee members.

     This is a  particular  example  of the difficulty  of using an
ordinal approach, (i.e. ranking), for the analysis of a technical
problem.  Formally,  individuals' rankings cannot be  reliably com-
bined because  individuals'  preferences  are  not  comparable.   In
the subcommittee's  judgment, however,  the procedure  was legiti-
mate as  it served  only as  a   focus  for  organizing  discussion.

     6.  The list of issues for consideration by the Subcommittee
omitted two that may have  been sources  of ground-water resource
impact as important as those that were considered: pathogens from
septic systems  and  salt  water  intrusion  into ground-water in the
Harbor area.   However,  a  previous TAG  decision excluded these
issues from the scope of the?IEMP Baltimore project.

     In the final analysis, the TAG -felt that despite the obvious
limitations of the method, with its  simplifications and frequent
reliance on judgment rather that data',  it fulfilled the intended
purpose.  It pointed out the issues for further study in Phase II
that  appeared  to  have  the  greatest  impact  on  ground-water
resources, and  were most appropriate for  further study by IEMP.

     The Phase  I work  of the Ground-Water Subcommittee was thus
complete, after the TAG  accepted the recommendation  of USTs and
metals for further  study.   The  Subcommittee  proceeded to develop
a workplan for  USTs.   The  process  of developing a workplan which
included metals in  ground-water was  done by  a different subgroup
of the TAC->  specifically the multi-media  metals  workgroup.  The
portion of their work  that applies'to ground-water is described
below.                --           '

ADDITIONAL ANALYSIS OF METALS IN GROUND-WATER

     Toward the  conclusion of  Phase I of the Baltimore Project,
the Ground-Water  Subcommittee   recommended USTs  and  metals  for
further study.  At the same time, other"Subcommittees also recom-
mended metals  for further  studv.   Therefore,  the proposed metals
studies were  combined and the  issue  was  re-named  "multi-media
                              VI-15

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metals." This  included  metals  in  drinking water,  in  air,  the
harbor, and  ground-water.   This issue  then,  became  very  broad.
The TAG  decided it  was too  broad  for Phase  II study  and they
wanted to define it  better  and  reduce its scope.  They therefore
set up  a  new workgroup, the multi-media  metals workgroup,  to
accomplish this  task over the  next three months.   This section
briefly describes the  multi-metal media groups overall approach,
and then  provides  their  results  which relate  to  ground-water.
More detail  on the  other aspects   of  the work  performed  by the
metals workgroup can be found in Chapter VIII.

     The multi-media  metals  workgroup  decided to make  a  second
review of  metals  in all media.   The approach  to studying metals
in surface water, air, and drinking water changed only minimally,
and the results are included in the chapters on human health risk
and ecological  analysis.   Additional   information was  found  on
lead, which  is  included in  the  human health  risk  chapter  and in
the chapter  concluding the priority-setting process.   More infor-
mation was available  on methods to  analyze ground-water than had
been available  previously,  so  the  multi-media  metals workgroup
reviewed this information as described below.

     The ground-water aspect of this review consisted of consult-
ing a study  that had  recently been  performed by the  EPA's Office
of Policy  Analysis.!2   This  national  study   estimated  likely
ground-water resource  impact  from a variety of  source types in a
wide variety of environmental settings.  The relevant sources it
addressed included  hazardous waste  landfills,  municipal  land-
fills, and five  types of surface impoundments (municipal  waste-
water treatment;  iron  and  steel;   metal  fabricating;  inorganic
chemicals; and organic chemicals).

     The basic analytic tool in the model is a ground-water model
known as the Liner-Location  Risk  and  Cost  Analysis  Model (LLM).
The LLM was developed by EPA's Office of Solid Wa'ste for estimat-
ing the  fate,  transport  and risks from hazardous  constituents
from landfills and  surface  impoundments.  The LLM contains nine
generic hydrogeologic  flow fields that represent different aqtti-
fer configurations (single and  multiple layer,  confined and un-
confined aquifers) and1 ground-water velocities  (ranging  from 1
m/yr to 10,000 m/yr).   These nine  flow fields were  used in con-
cert with four unsaturated zone thicknesses and  four net recharge
rates to create 144 possible environmental settings.

     Projected releases from  each source  were modeled in each of
the 72 environmental  settings.  It  was assumed  that  there was a
drinking water well  600 meters  downgradient of  each source, and
impacts were calculated on the basis  of the expected volume of a
plume of  contaminated ground-water passing by  this  well,  over
time.   Ground-water was defined to  be  impactd or contaminated if
it was polluted  at  concentrations  greater than  EPA's  drinking
                              VI-16

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water standards.  (It^would also be defined as polluted if it was
above taste and odor  thresholds,  but the metals modeled have  no
known taste or  odor thresholds.)  Impacts were  calculated  over a
400-year horizon.

     The model did not address  all  the  metals that  are likely to
leach .from these  sources.   (The  only  metals included  for  these
sources are  those thought  to  be  most toxic,  persistent,  and
mobile.  These are: arsenic, cadmium, chromium  VI,  and mercury).
In addition,   a number  of  types  of  surface impoundments  which
exist in Baltimore are excluded in  the  study.   Specifice  sources
in Baltimore also differ  from  the  "typical"  national  sources  in
model in  size, leachate  content  and  concentration,  and  other
parameters.

     However, the model indicated that  each of the  source types,
as well  as the closed hazardous  waste  landfill  and  the  chrome
tailings fill,  showed a  likelihood  of  causing resource  impact.
The pollutants  responsible  for  this  resource  impact  included
arsenic and  cadmium   for  municipal  landfills,  and  chromium  for
the other  sources.  The multi-media metals  workgroup  then inter-
preted- the modeled results in light of the actual exposure situa-
tion in Baltimore.  Most of the  surface impoundments,  the closed
hazardous waste landfill,  the chrome ore tailings fills and some
of the municipal  landfills  were all located  in industrial areas
where the  ground-water  was  already  degraded.   Therefore  any
ground-water resource  impact  which might  occur would make  an
already polluted situation  somewhat worse,  rather than contamin-
ating ground-water that is clean,  but unused, and miqht be needed
for future uses.

     Potential human health risk was  also considered  for these
sources.   In the  Baltimore  study  area,  however, all of the sur-
face impoundments were in industrial sections of  Baltimore City,
where ground-water was already  substantially  contaminated  and
unlikely to  be used  for  drinking  in the  foreseeable  future.

     In addition,   5   of  the 24 landfills  are  located  in areas
where the  ground-water is used  for drinking.  All open landfills
and some closed landfills have ground-water monitoring wells sur-
rounding them.  This monitoring has shown no evidence of contami-
nation by  metals  at  levels of  concern.   This does not mean,  of
course, that there could never  be a problem in the  future. .With
the very  slow ground-water movement  in the  Coastal  Plain area,
contamination could merely be delayed.

     Using this  information,  the  multi-media  metals  workgroup
found no actual human health risk.  They  believed  however, that
municipal  landfills could potentially cause ground-water resource
impact.  If  not  carefully  monitored,   they  could cause  human
health risks.   Because  monitoring  is  already  occurring,  and
                              VI-17

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because of the high cost of  any additional  monitoring,  the Work-
group decided not  to  recommend that IEMP fund  a monitoring pro-
gram for municipal landfills.

     The Workgroup  did,  however,   recommend  that  the  counties
ensure careful monitoring of both open and closed municipal land-
fills in the areas where  ground-water is presently used for drink-
ing, or might be used in the future.  This is particularly impor-
tant for  metals,   because  they  can cause  substantial   risks  at
levels not detectable by humans through taste or  odor.   This is
in contrast to many organics,  which can be tasted  or smelled at
very low levels.   People presumably stop  drinking the water when
it tastes  or  smells bad.   Such avoidance  substantially reduces
an individual's exposure to, and  therefore  risk  from,  contami-
nated ground-water.
                              VI-18

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                      Addendum" to Chapter VI

         Ground-Water Resource Impact Scoring Methodology

     In developing the Phase  I screen, the  Subcommittee decided
to provide two scores for each issue — Pollution Impact and Eco-
nomic Impact.  Both  affect  decisions on  ground-water  assessment
and management.

     Pollution Impact (P) and Economic Impact (E) were  treated as
separate criteria.  The  Subcommitte  recommended scoring  each  of
them separately so that  the flavor of the one  could be compared
to the other, rather than being lost in a single numerical score.
The two  scores could later be  combined  in various  alternative
ways to provide a single  score for relative ranking of  the issues.

     Each of  these  criteria  was  split  into  units:    Pollution
Impact into three units,  and  Economic  Impact into two  units.  In
turn, units were further subdivided except for E.I. Each subunit
(such as P.I.a.) was scored,  with  5=high,  3=intermediate, and 1=
low.  These  scores were  averaged for each unit,  as shown on the
final page.  In turn the units were averaged to determine a score
for the  criterion, as  shown  on  the  last page.    Ihe final score
was reported as:  Pollution Impact/Economic  Impact.   (4/5 or 1/3
for example)

     Definitions:  In this  process  the  Subcommittee   used these
guidelines for scoring each unit:

  -   P.I.a. number  of  facilities  comorising  the  source  type
            1= 1 to 10
            3= 11 to 100
            5= 100 +

         b. release volume over time for one facility
            1= small;  less  than  the  capacity  of the   facility
            5= large, continuous

         c. concentration of contaminants
            1= dilute
            5= very concentrated (e.g; - gasoline)

         d. persistence of contaminant
            1= degrades within one month
            5= degradation exceeds one year

     P.2.a. present extent of contamination
            1= few examples of contamination
            5= many examples of contamination
         b. future extent of contamination
            1= safe  or  lower  rate   of   contamination  incidents
            expected over next 10-20 years.
                              VI-19

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                       Addendum (page 2 of 4)


            5= much  higher rate  of contamination  expected  over
            next 10-20 years       ;

P.3    Potential extent of impact refers to whether or not source
       types are more densely distributed in areas where they are
       more likely to cause more impact.

P.3.a. Hydrogeologic  setting.   A high  score here  would  imply a
       source type is more densely distributed in a hydrogeologic
       setting which is particularly  vulnerable.   The Subcommit-
       tee believed  Coastal  Plain area  (located  SE of  the  fall
       line) is more vulnerable because there are few barriers to
       transport; contaminants  continue to  move  for  years  over
       significant distances.   In  the Piedmont area,  (NW of the
       fall line)  however,  transport  occurs  for  fairly  short
       distances, usually no further than the edge of the surface
       water drainage area (i.e. local watershed), where the con-
       taminated ground-water may be  discharged  to surface water
       streams.  Therefore,  sources densely  distributed in Coas-
       tal Plain hydroqeology would be  ranked 5,  sources densely
       distributed in Piedmont  hydrogeology would be  ranked  1,
       and sources  equally distributed among  both hydrogeologic
       types would be ranked 3.

P.3.b  Population served by affected wells. Using parallel reason-
       ing to the situation above, sources located preferentially
       where a large  in areas  of  Anne Arundel County served  by
       municipal ground-water)  would  be  scored  5; and  sources
       located preferentially in areas  where there is no ground-
       water use  (perhaps  because  ground-water   in the  area  is
       already badly contaminated) would be ranked 1.

P.3.c. Industries  served  by affected  wells.   Sources  located
       where a large amount  of  industry using well water may be
       affected would be scored 5; and sources located preferent-
       ially where water is presently too contaminated for indus-
       trial use would  be  ranked 1.  (This  category  is separate
       from 3b because industrial users can often tolerate higher
       concentrations of contaminants in water they use.)

E.I.   Prevention - To be more accurate, this is really "reduced
       likelihood of contamination"  because accidents  will  con-
       tinue to occur.   This measures  the  likely costs  of all
       reasonable prevention  programs  such  as  tank  permitting
       programs,  the goal of which is to prevent future pollution.

E.2.a. Response - One form of response  is alternative supply,  or
       in other words,  the cost of providing an alternative water
                              VI-20

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                     Addendum .4page 3  of 4)


   supply.  Examples of alternative supply are  bottled water,
   and extending city water supplies (from reservoirs).  This
   will vary primarily in proportion  to  population  affected.
   1= a few homes
   5= alternative  supply  for a large  municipal  well  field
                      *
b.  Response - A second form of response is treatment,  or in
    other words the  cost  of providing treatment.  This  will
    vary primarily in proportion to the extent  of impact.   It
    will also vary with the type of pollutant.
    1= economically treatable at individual household level
    5= large scale purging of  aquifer over months or years
                           VI-21

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                 Addendum (page 4 of 4)



MATHEMATICAL APPROACH FOR GROUND-WATER RESOURCE SCORING

Pollution Impact (1+2+3) / 3 =

1.  Source characteristics (a+b+c+d) / 4 =

    a. number                                  (     )
    b. release volume over time                (     )
    c. concentration of contaminants at        (     )
         point of release
    d. persistence of contaminants             (     )

2.  Likelihood of contamination (a+b) / 2 =

    a. present                                 (     )
    b. future

3.  Potential extent of impact (a+b+c) / 3 =

    a. hydrogeologic setting                   (     )
    b. population served by affected wells     (     )
    c. industry served by affected wells       (     )

Economic Impact (1+2) / 2 =

1.  Prevention (cost to reduce likelihood      (     )
      of contamination)

2.  Response to contamination (a+b) / 2 =

    a. alternate supply                        (     )
    b. treatment                               (     )
                         VI-22
                                                          11111 HI

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                            Footnotes
1.  EPA, Regulatory  Integration  Division,  "Baltimore IEMP  Issue
    Summary Paper:  Septic Tanks",  February  1,  1985.

2.  Personal communication between Dr.  Emery T.  Cleaves,  Maryland
    Geologic Survey  and  Hope  Pillsbury,  EPA,   November  1986.

3.  Personal communication between Jim Dieter,  Baltimore  County
    and Ed Weber, Maryland Department of Natural  Resources,  with
    Hope Pillsbury,  EPA,  November 1986.

4.  Personal communication between Reid Rosnick,  Maryland Depart-
    ment of Health and Paul  Lewandowski,  Sobotka and Co.,  Inc.,
    quoted in  EPA,  Regulatory  Integration Division, Memorandum
    from Sobotka &  Co.,  Inc.,:    "Baltimore  IEMP Issue  Summary
    Paper:   Landfills Working Draft",  February 1,  1985.

5.  Personal communication between Bob Beyer,  Maryland Department
    of Health and Paul Lewandowski, Sobotka,  Inc., quoted in EPA,
    Regulatory Integration Division,  Memorandum  from Sobotka  &
    Co., Inc.,   "Baltimore  IEMP Issue  Summary Paper:   Landfills
    Working Draft",  February 1, 1985.

6.  Personal  Communication  between Brooks  Stafford,  Baltimore
    County, and Hope Pillsbury, EPA, March 1987.

7.  Environmental Source and  Engineering Inc.7  "Assessment  of
    Contamination -  Phoenix  Military  Reservation Final  Report"
    July 15, 1983.

8.  EPA, Addendum to Working  Draft for Baltimore Technical commit-
    tee.  Multi-Media metals.  undated.

9.  Anne Arundel County  Health Department, Mayo  Peninsula Water
    and Sewage  Survey,   1978,  quoted   in  reference  #1,  above.

10. EPA, Regulatory  Integration Division,  "Surface  Impoundments
    in the Baltimore Study Area",  April 24, 1985.

11. McGlincy, D.A.,  J.T.  Chaconas,  andB.D. Huang. 1980.  The Mary-
    land Surface Impoundment Assessment Program:  A Final Report.
    Maryland Department of Natural Resources, quoted in EPA, "Sur-
    face Impoundments in the  Baltimore Study  Area", April  24,
    1985.

12. EPA, Regulatory  Integration  Division,  "ground-water Resource
    Degradation Ranking for Chromium in the Area Around Baltimore
    Harbor", April 25, 1985.

13. EPA, Regulatory Integration Division, "Chromium in and Around
    Baltimore Harbor", April 24, 1985.

14. EPA,  Regulatory  Integration  Division,   "Draft  Comparative
    Impact Analysis  of  Sources  of  Ground-Water  Contamination
    Phase II Draft Report", March 27, 1986.
                              VI-23

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VII. ANALYSIS OF ECOLOGICAL IMPACT

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              VII. ANALYSIS OF ECOLOGICAL IMPACT
     Several of the initial thirty-two issues the TAG  identified
as important to analyze  in  this study dealt with the  ecological
condition of Baltimore Harbor and  its  tributaries.   To establish
study priorities among pollutants  and sources of pollution  that
enter these bodies of water, the TAG  recognized that it needed a
priority-setting method that covered ecological effects.

     No analytic device for this purpose was readily apparent  at
the outset of Phase I of the IEMP.   Therefore,  the  TAG  decided  to
have project staff spend their  initial efforts evaluating exist-
ing studies on the Harbor and its tributaries and  to collect  some
data on levels of  various harbor pollutants in a monitoring study.
From these  efforts,  the TAG  recognized it  could  take  existing
data and develop an ecological  "index" rating  for  various harbor
pollutants to assess  the  relative  significance they may  have  on
the ecological health of these water bodies.   The pollutants  with
the highest index numbers would represent the  chemicals most im-
portant to study in Phase II.

     This chapter presents,  first,  a  section which  describes the
difficulty of defining problems one might examine  in  the harbor
a.nd the approaches to studying them.  The second  section provides
background on  biological  and  pollution-related  aspects of  the
harbor.  The third section  describes  a harbor  monitoring program
which EPA  undertook  in  1984,  to obtain  an  improved  data base.
The fourth section presents  how the method for setting  priorities
for ecological impact "was chosen and  applied.  The  fifth section
summarizes results and limitations of the Phase I  harbor studies.

     The Baltimore Harbor was  included in the  IEMP study for a
number of reasons.  First,  there was  State and local concern for
the ecological health of the harbor,  the  viability of  the harbor
as a resource for  fishing and recreation, and its aesthetic value.
Second, there was concern regarding the adverse effects that  pol-
lution in the harbor may have on the Chesapeake Bay.  An addition-
al reason  to  study the harbor  was to  further  the goals  of the
Chesapeake Bay  Initiative,  a  major  cross-government   effort  to
preserve,and improve  the Chesapeake  Bay as a natural resource.
Finally, the harbor  provided the  first  opportunity for  IEMP  to
address ecological impacts in an IEMP study.   EPA saw the need to
develop and apply  priority-setting methods  to ecologic impacts,
and in particular,  ecologic impacts  on an  aquatic environment.

     The scope of  the study did not  include the  Chesapeake  Bay.
The Chesapeake Bay  is too large geographically,  and in addition
was too complex a topic for the resources of the IEMP.   Therefore
the study area was restricted  to Baltimore Harbor.  Data limita-
tions led to the  decision to restrict the examination of ecolo-
gical effects  to  those  pertaining to  the  aquatic  environment.
                              VII-1

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DEFINING AN APPROACH TO THE HARBOR ISSUES

     There are as many goals  for  the harbor as there are potential
uses.  Ecological health of the harbor can be defined in terms of
any or all  of these goals.  The  principal question  posed  by the
TAG was whether it could identify a cost-effective way of attain-
ing any one of  these  goals.  The harbor  subcommittee believed it
lacked the  information  necessary  to  address  this major question.
Therefore, it approached this question in terms of several subsi-
diary, but fundamental questions, which follow:

        0  Is  the harbor  a  source  or  sink  for  pollutants?  In
           other words,  does the  harbor serve  as  a source  of
           pollutants to the Chesapeake  Bay  or  act as a  sink for
           pollutants discharged  into  the  harbor  or  entering
           from the Chesapeake Bay?

        0  What is  the relative contribution which  pollution in
           the sediment  and  pollution  from direct  dischargers
           (point and  non-point)  make to the  ecological  health
           of the harbor?

        0  What is the relative  importance of specific pollutants,
           and pollutant  classes, to  ecological  health of  the
           harbor? Are  the  so-called  "conventional"  pollutants
           (i.e.  dissolved oxygen and nutrients)  or the "toxic"
           pollutants (metals and  organics,  such  as pesticides)
           more limiting  to  harbor life?  Within each  of  these
           groups, which specific pollutants cause the most harm?

         0 What is the  relative  importance  of  habitat (including
           food chain effects, physical  factors  such as  tempera-
           ture, salinity, suspended  sediments  due  to dredging,
           and existence  of  appropriate  spawning areas)  versus
           pollution, in determining the ecological health of the
           harbor?

     The harbor subcommittee was aware that in order to determine
which, if any of these issues they could address, they would need
to determine  what information  was currently  available for  the
five basic  elements  of iany  study  of  pollution:  pollutants,
sources,  environmental  fate  and  transport,  ambient  data,  and
impacts or damages to  the  biota of concern.,  The following pre-
sents background  information  on  these  elements  for  the'harbor.

     Over the course of Phase I  the harbor subcommittee  was also
called the harbor  workgroup.   Thus,  the  term   subcommittee  and
workgroup are used inter-changeably throughout this report.
                             •VI1-2

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HARBOR OVERVIEW
      -- "               .          **
Pollution Impacts on Biota

     A study performed by the Center of Environmental and Estuarine
Studies (GEES) in 19751 compared the ecological health of Baltimore
Harbor to that of the Chester River, a  relatively unpolluted tri-
butary with similar latitude and salinity levels  as.the Baltimore
Harbor.  The  intent  of  the  comparison  was  to determine  whether
Baltimore Harbor's ecology has been adversely affected by pollu-
tion.

     For fish,  the  GEES study  found that  the  Baltimore  Harbor
water column supports a wide variety of ,life and  serves as a nur-
sery and  feeding ground for  many  species.   In  fact,  the inner
harbor supported various fish populations.

     The researchers  observed that striped bass  and  hogchoker
were not  spawning in Baltimore Harbor.   In addition,  the juve-
niles of several  bottom feeders,  the hogchoker,'winter flounder,
and the Atlantic  croaker, were  absent  from  the Harbor.  Possible
reasons for this  include pollution and  habitat; however the study
was not able  to accurately identify the  reasons for  failure  of
certain species'  life-stages  to  be present of  to  spawn  in the
harbor and its tributaries.

     Ecological principles dictate  that the ecological health of
benthic organisms  can be  affected  by  stresses  such  as  pollu-
tion2^3.  Unlike  fish that  swim from environment to environment,
benthic  organisms are  primarily sedentary bottom-dwellers.
Because they feed and breathe close to  the highly polluted bottom
sediments, they  are very susceptible.to exposure to pollution in
the sediments.

     Two possible indicators  of  environmental health  of  benthic
organisms are benthic biomass and the number of benthic species.1
GEES researchers  compared  these  parameters in   Baltimore  Harbor
and the  Chester  River.   The Baltimore Harbor  had  a  lower dry
weight of benthos and about one third  fewer benthic species than
did the Chester River.  These findings  suggested  to them that the
sediments of Baltimore Harbor provide  a less healthy environment
than the sediments of the Chester River.1               ,

     The researchers classified the Baltimore Harbor  into three
zones based  on sediment pollution:  1)"a semi-healthy zone from
the* harbor mouth to Fort Carol!;  2) a semi-polluted  zone from
Fort,,Caroll  to Fort McHenry; 3)  and a polluted  zone ;within the
inner ftarbor  and the tributaries.   (See  Figure  VII-1 for map).

      The GEES study provides information on the biological state
of the Baltimore  Harbor during the 1970's.   Environmental condi-
tions may have  changed  since then due  to pollution abatement and

                              VII-3

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natural environmental  processes.    Although   the   ambient  water
could support diverse fish life during the  study period,  the GEES
study suggests  that the  Baltimore  Harbor and  its  tributaries
could not  support  the  entire  life  cycles  of-  certain fish,  nor

does it support the diversity or biomass of benthic  species that
would be possible if it was less polluted.

Sources of Pollution in Baltimore Harbor

     By convention  EPA divides sources  of water  pollution  into
two categories: point  sources  and non-point sources.  The  point
sources are industrial  facilities and sewage treatment plants dis-
charging effluents.  The non-point sources consist of activities
leading to urban and residential  runoff  that enters  from streams
and storm  drains  which empty  into  the  harbor.    Two  additional
sources that may pollute the Harbor  are  accumulated pollution in
the sediments, which is described in the section on ambient  data,
and air deposition  of  pollutants  directly  into the harbor,  which
we deferred  to  Phase   II  because  of  resource  considerations.

Point Sources

     Data was available for the first three categories of sources
of pollution to the harbor.  We consulted  NPDES (National Pollu-
tion Discharge Elimination System) permits  for information on the
"major" facilities  polluting the harbor.   The  27  "major" facili-
ties include the Patapseo and Back River sewage treatment plants.
                                '•-." '      * -
     A total  of  27 "major" dischargers  produce  a total  of over
2 billion  gallons/day  of  .effluent.   The 135  "minor"  sources of
direct discharges  together  are estimated  to  provide  21 million
gallons/day of  effluent  to the harbor.41  in  contrast,  non-point
sources are  estimated  to  provide  an  average  of  107  million
gallons per day of effluent to the harbor5»6.

     EPA's definitions of major and minor dischargers is based on
knowledge of  the usual toxicity and concentrations of pollutants
discharged from facilities,  based on their SIC  (standard indus-
trial classification)  codes.   Therefore  unless a  facility's dis-
charge is  grossly  more t6xic or  greater in volume than expected
given its SIC  code,  it is reasonable to assume that the "majors" (
provide substantially  greater  loads  of toxics  to the harbor than'
do the " mi nors " . ^

Non-point Sources

*>     We examined three types  of non-point source  runoff catego-
ries:  urban  stormwater  runoff, agricultural  stormwater runoff,
and forest  stormwater  runoff.   To get  expected contribution per
acre of pollutants  from urban stormwater runoff, we used monitor-
ing data  from the  Jones Fall Urban Runoff Program.8  This was an
intensive study of one rivershed, the  Jones  Falls,  in Baltimore

                             ' VII -4

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City and County.  We extrapolated data from this urban  watershed
to the other urban watersheds in the Baltimore region.   To deter-
mine expected contribution per acre  of  metals  and pesticides  from
agricultural and  forested  lands  in  the  study  area,   we  used
studies in Lancaster,  Pennsylvania  and the Rhode  River  area  in
Maryland.   We determined the  acreage  in  each  watershed  which  is
urban, agricultural,  and  forested,  using 1975  data  on  land use
from Baltimore  Regional  Planning Council  and  the  NASA  Landsat
Program.  Then,  using  the  data from the monitoring  studies  men-
tioned above, we  estimated average  annual loadings  by  pollutant
from non-point  sources  for the entire study  area.5»6   These are
very rough estimates  because  the specific  types of  agriculture
and forests  studied  are  not  identical  to those  found in the
study area.

     The non-point source discharge  estimates  do not  include  ade-
quate data on two potentially  important  categories:   runoff  from
industrial lots  (including  stockpiles,  work  areas,  etc.)  and
sanitary sewer  overflow  (which occurs during  storms).   Of these
two, defining and quantifying  pollution  loadings from industrial
areas appears to be the most important to pursue since these  dis-
charges can cause high chronic toxicity.

     A third possibly major source of non-point source pollutants
is run-off carried down the Susquehanna River  into the Chesapeake
Bay and the  Harbor mouth.   We were  not able  to estimate  this
pollutant load to the harbor.

     Table VII-1 compares  the mass  of different metals that are
discharged by point sources  versus  non-point  sources.   For these
metals, point source discharges  are at least 10 times  and often
more than  100  times  greater  than  the  non-point  discharges.
Figure VII-1 provides  the  total mass loadings  from  major direct
discharges, by  pollutant.   We also distinguish  between the  mass
contributed by  Bethlehem Steel, versus  all  other major sources
combined,  for each  pollutant.  For  all  metals  shown,  Bethlehem
Steel is the  single  largest  individual  source.   This  is due  in
part to this facility  being  much  bigger  than  any other facility.

Information on Fate and Transport

     Information on fate and transport of  pollutants in  the har-
bor is  sparse.   Maryland's Office of  Environmental  Programs has
developed a hydrodynamic model of  the harbor.  The model, however,
does not describe  all the complexities  of  flow in the harbor.
The harbor has been observed showing  an  unusual three-layer  flow
near the mouth, at  certain times.  Water in  the upper and lower
portions (vertically)  of the harbor  moves  into the harbor,  and
water in the middle section moves out of the harbor.  In addition,
the model does  not address water  quality,  or  provide information
on the fate of pollutants in the harbor.  It would be very expen-
sive to augment the model to provide such information.9
                               VII-5

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                           Table   VI I-1
                          BALTIMORE IBMP

             DISCHARGES TO BALTIMORE' HARBOR OF METALS
                       (1000 kg/year)
              MAJOR POINT SOURCES1
                        ESTIMATED NON-POINT SOURCES2
Zinc
Cadmium
Mercury
Lead
Chromium
Copper
Nickel
Arsenic
Beryllium
Antimony
 411.9
  42.4
    .915
 457.2
 182.6
 158.43
 707.17
 159.11
   3.2
  17.0
18.3
  .4
 N/A
14.0
 2.7
 5.1
 3.9
 1.1
 0.1
 0.4
TOTAL
2139.9
46.0
1. Source of data  is EPA discharge monitoring reports, collected
   for the National  Pollution Discharge Elimination System.  Data
   is for  1983-1985,  except  1982  data  for  Bethlehem  Steel.
   Only "major"  dischargers  were included.  Metals were  included
   if they  were discharged  by at least  two "major"  facilities.

2. Source  of data  is the Baltimore Regional  Planning Council's
   "Jones Falls  Watershed Urban Storm  Water Runoff  Project,  "
   Interim Report.   Baltimore,  MD.,  1982.   For  method  used  to
   estimate direct  discharges of  metals  from non-point  sources,
   see p. VI1-4;

N/A indicates no data available.
 HI IB HIPI' in 'lli'iiffllllp
                                                              ri|iin in fi

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                                Figure VII-1

                              Baltimore IEMP
                     Mass Loadings to Baltimore Harbor
                                    (372)
                                                    All Other Major
                                                    Point Sources
             •°°°°°°°°°°o°°°oo°°°°°°°o°°°°°°°°°°°°°°™
             (24.9)
                    (134.3)
                 100    200   300    400    500   600
                    Cumulative Mass Loadings to Baltimore
                            Harbor fcko/yr)
700
Source of data is EPA discharge monitoring reports, collected for the
National Pollution Discharge Elimination System for "Major" point sources.
Data is the yearly average for 1983-1985, except for Bethlehem Steel,
which is 1982 data.

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Assessment of Ambient Data

     A review of available information on ambient water concentra-
tions and sediment  concentrations  of toxics in  Baltimore  Harbor
revealed very  little  data on ambient water "concentrations.   The
EPA STORET  data base contained  toxics  data for  several  of  the
tributaries to  Baltimore Harbor, but .nothing for  the  estuary  it-
self.  Only one  study, a  1977  report produced  for EPA by Trident
Engineering, had data on  toxics  in ambient water  in  the harbor.
Several studies, however,  showed Baltimore Harbor sediments to be
enriched with both toxic organic compounds and  metals.

     A geographic range of pollution was  found for metals in  the
sediments.  A study performed  by Villa  and Johnson in 1984 moni-
tored sediments  at  over  150 locations,  evenly  spaced throughout
Baltimore Harbor.  They found  that levels of  metals  are highest
near the mouths of  the tributaries  to  the harbor, and  lower in
the middle areas of  the harbor.   The  location and spatial arrange-
ment of this area's range  in pollution  was similar to that found
for biota in the sediments.  (See p.  VI1-3.)

Information on  Specific Pollutants a;nd Biota

     Much of the information on  specific  pollutants was reviewed
in the context  of  biota,  sources  or ambient data.  However,  one
study pertaining to aluminum and its possible  effect  on spawning
of fish, deserves special mention, and is  included-.here.

     This issue  is  one that has been  researched  extensively by
the Smithsonian  Environmental  Research  Center  in Anne  Arundel
County.  Analyses indicate that  acid  rain as well as the  use of
nitrogen fertilizers  can  acidify rainwater   and   ground  water,
causing metals,  particularly aluminum,  to leach  from soils  into
surface and ground water.   This acidic water may then impact  fish
and amphibian ^populations.   The  low  pH and, aluminum  are  thought
to be  toxic,  perhaps  synergistically,  to,  fish  and amphibians
including larval stages.

     The results of  the  Center's  studies  suggest a correlation
between increasing levels of acidity in area streams  and decreas-
ing larval  survival  in  fish  species  such  as striped' bass  and
yellow perch.   In some  streams :in the  Rhode River Watershed the
total extinction of these species, and others,  has .been recorded.
This situation  is especially acute in  areas with pboirly buffered
soils (i.e. low  alkalinity), such  as those in  the  Atlantic Coast-
al Plain r-egion, which encompasses the  entire  eastern portion of
the study area.  0      '

DEFINING AN APPROACH TO STUDYING THE HARBOR

     lEMP's early consideration  of how  to set  priorities  for the
                              VI1-6

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harbor led  to the  concern that  we  needed more  data.   lEMP's
initial assessment showed a need for data on pollutant  concentra-
tions in  biota  in the harbor,  environmental fate and  transport
of pollutants in  the harbor,  and  ambient  water  quality  in  the
harbor.   .

     Because studies  were  ongoing  by  the  State  of  Maryland  on
pollutant concentrations in Harbor  biota,   we decided  to  address
the latter  two  questions.   The IEMP chose a monitoring  rather
than a modeling  approach because a modeling approach  would  have
been prohibitively complicated and expensive.
                          ;

HARBOR MONITORING

Objectives of the Monitoring Plan

     The  IEMP designed  a monitoring plan to characterize  condi-
tions near the mouth of the Harbor and to provide a better under-
standing  of the inter-relationship between  the Harbor and Bay.  A
second goal was to  improve the  characterization  of ambient water
quality in  the  harbor.   As it  turned out,   this latter  goal was
achieved  but little light was shed on the first goal.  The speci-
fic objectives  of this  monitoring  and  analytical plan  were as
follows:

     o  to  obtain a  data  base to  identify water quality para-
        meters which  may be limiting to  aquatic  organisms in the
        Baltimore Harbor.

     o  to determine  if  there is net pollutant inflow to the har-
        bor from  the Chesapeake  Bay, or  net pollutant   outflow
        from the  harbor  to the  Bay.  This would be determined by
        examining any  differences  in  pollutant  concentrations
        that are  present  between  the  inflowing  and  outflowing
        Baltimore Harbor waters during two  12-hour periods.

     o  to  learn more  about  the  role   the harbor hydrodynamics
        play in  harbor  water  quality  variations,  by gathering
        more  information on when and where  the tide  flows  in  two-
        to-three  layers  and' in  one  layer.

     Due  to  funding  constraints,   the  monitoring  was extremely
limited and  should  be   viewed  as  providing some "snapshots" in
time of levels  of certain pollutants in ambient water at  certain
sites  in  the harbor,  in  a  variety of tidal  and meteorologic  con-
ditions.    The monitoring  is  not  a  detailed,  statistically valid
assessment  of pollutant  concentrations.   In addition,  because of
the  limited number  of samples collected,  only  the  first objective
above  was partially  met;  the  results  of  the  monitoring cannot
address the other two objectives.
                               VI I-7

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Pollutants Selected for Analysis

     Prior to  making  a  final  selection  of  parameters,  IEMP
comprehensively reviewed and analyzed existing data.  In addition,
we performed a preliminary monitoring program on  July  9,  1984 to
test detection limits  for pollutants.   Table VII-2  presents the
water quality parameters EPA chose for the Baltimore Harbor water
sampling study based upon a review of previous monitoring studies
and EPA  Discharge  Monitoring Reports^*11.  The pollutants found
were primarily metals, phenols, cyanide,  and  purgeable organics.

     IEMP analyzed for both the total and dissolved metals.  Most
ambient water quality criteria for protection of aquatic life are
based on total metals.  Total metals are  also  required to relate
source loadings to ambient water  quality  data (point source dis-
chargers are only required to monitor total metals).   The portion
of total metals  which are dissolved is important  in the aquatic
ecosystem because they  are the most readily bioaccumulated and
their concentrations  in  the water  column  must  be  known  before
assessing potential impacts to the biota.

     IEMP monitored pesticides because  they may be  carried into
Baltimore Harbor by the Susquehanna  River  water and  by non-point
source runoff.  IEMP monitored metals and some polynuclear aroma-
tic hydrocarbons because they could  be  associated with eutrophi-
cation, low dissolved oxygen,  and fish kills.   In addition they
may be harmful to phytoplankton,  the primary  source  of the aqua-
tic food chain.

     Finally, physical parameters of dissolved oxygen,  water tem-
perature, salinity,  conductivity,  and  current  direction  were
monitored to provide  some  indication of vertical  differences in
the, water column and  to help identify the different  flow layers.

Sampling Plan

     A preliminary monitoring  effort was   conducted on July 9,
1984 to determine detection limits (detection sensitivity) of the
planned monitoring and analysis techniques and to determine which
parameters to analyze.  Based on  these  results  a  more  comprehen-
sive monitoring program was  designed and  discussed  with members
of the scientific  and regulatory community.^  After  incorpora-
ting the contributions of these experts,  a final  monitoring plan
was developed.*3.

     The monitoring program  was  conducted on September  12, 1984
and September 26,  1984.   Although the majority of planned samples
were collected, some  were not  due to rough seas  and high winds.
Both of  the  planned  sampling  dates were  preceded  by unusually
long periods of dry weather.  The  period following  the  second sam-
pling day,  however, saw  several days of  rain.   Because rainfall
                              VI1-8

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                           Table VII-;-

                         Baltimore IEMP

                     IEMP MONITORING PROGRAM
                           PARAMETERS


                    General Water Chemistry

Total Dissolved Solids                 Total Suspended Solids
Nitrate                                Orthophosphate
Cyanide, Total


                    Metals (Dissolved/Total)

Beryllium                              Cadmium
Chromium, Total                        Calcium
Copper                                 Lead
Magnesium                              Manganese
Mercury                                Nickel
Sodium                                 Zinc


                            Organics

Total Organic Carbon                   Polynuclear Aromatic Hydrocarbo
Phenols , Total Recoverable             Purgeable Organics  (Volatile
Pesticides (13 specific pesticides)      Organic Compounds)


                        Other Parameters

pH                                     Salinity
Conductance                            Flow direction
Temperature                            Dissolved Oxygen

-------
 increases  the  volume of non-point source runoff, the IEMP decided
 to  compare ambient  water  quality both before and after rainfall.
 A third  day of  sampling  was  therefore conducted  to  observe any
 measureable effects  of  nonpoint  sources.    This   "wet  weather"
 sampling was carried out  on October 5, 1984.

 Sampling Station Locations

     The Baltimore Harbor monitoring  plan  included 13 monitoring
 sites; 11  in the harbor,  and  two in the bay, outside the harbor.
 Figure VI1-2 shows  the location  of the various  monitoring sta-
 tions in the Harbor.   The numeric stations  were  sampled at var-
 ious depths and  were  intended to be used to determine net inflow
 or  outflow of  pollutants  at  the Harbor/Bay interface.  The alpha
 stations were  sampled  at  mid-depth and were  intended  to be used
 to  determine spatial water quality variability within the Harbor.

 Quality Assurance/Quality Control

     Before the  monitoring began, a formal Quality Assurance (QA)
 Plan was  prepared  by  EPA Headquarters  and  approved by  EPA's
 Region III.  The plan  outlined the scope  of the monitoring pro-
 gram, the  objectives of the program and the reasons for selecting
 particular  monitoring  sites in  the  harbor.   The QA plan also de-
 tailed the  exact procedure to be used in the collection, handling
 and analyzing  of samples.  The plan established  quality control
 procedures  to  be  followed  throughout  the  program  including:

     o Field blanks for VOA's, PAH's, and metals,

     o Sample container cleaning procedures.

     o Sample custody procedures,

     o Standard equipment combination and maintenance, and

     o Data  validation measures.

 Results of  IEMP Monitoring

     Table VI1-3 shows the maximum  observed metals concentration
during the  dry weather sampling (September 12 and  26,  1984) the
wet weather  sampling (October 5, ,1984} mean values of the sampl-
 ing, published sampling data  (Trident 1977)  including mean values,
and EPA chronic  and acute effects criteria  levels  for saltwater
organisms.    (USEPA 1980).   No pesticides were found.1*

     The initial analysis of  this data,  and other available data
suggested the following to us:

     o Water column concentrations  for  metals with corresponding
       EPA ambient water quality criteria did not exceed the acute
                               VI1-9

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                          Figure vii~ 2
                            Colgate Creek
                    Lazaretto Pt.
NAUTICAL MIES

    \_X Trident Sampfng Sites
         IEMD Sampling Sites

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                                                     Table VII-3
                                                      BALTIMORE IEMP

                                     MONITORING DATA AND EPA CRITERIA USED IN ANALYSIS
                                                    CF BALTIMORE HARBOR
Parameter
(Units)
IEMP Data, 1984-1-
7/9
9/12
9/26
10/5
("Wet)
Weather")
Mean"*
(Metals
only)
Trident Data-*
Range 1977 Mean4
(Metals
only)
EPA

Saltwater Criteria-3
Chronic
Acute
Beryllium (ug/1)
Cadmium (ug/1)
Chromium (ug/1)
Copper (ug/1)
Lead (ug/1)
Mercury (ug/1)
Zinc (ug/1)
Nickel (ug/1)
PAHs (ug/1)
VQAs (ug/1)
Pesticides  (ug/1)
<0.25
<0. 5-1.1
<4.0-4
<10.0
3.5-5.4
<0.2-0.24
<4.0
<4. 0-6.0
*
*
*
<1.0
<0.5-1.5
<4.0-12
<2.0-9
<5_,0-9.6
<0.2-0.5
<3.0-19
<15.0
<2.0-32
<10.0

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       24 hour  exposure  concentration  though some  exceeded the
       corresponding EPA   chronic  criteria  concentration.   The
       metals for which exceedances of EPA's  chronic  salt water
       criteria occurred  in at least one  data set,  are mercury/
       lead,  copper, nickel,  cadmium and zinc.  Therefore, ambi-
       ent metals concentrations  in Baltimore Harbor  are likely
       to have   adverse  sub lethal  effects  on aquatic organisms
       but are  not likely to  directly cause fish kills.

     o Interstitial waters tend to exhibit metals concentrations
       ranging  from  two  to  five times  greater than  the  water
       column,  and  interstitial waters consistently exceed  acute
       ambient  criteria for the  six  metals  listed above.   While
       there are no criteria  for interstitial waters, the  rela-
       tively high  concentrations will  tend  to  adversely  impact
       benthic organisms   and  impede the  reproduction of  bottom
       spawning organisms in  the  harbor.

     o Metals  concentrations  in  the   sediments  tend  to  vary
       substantially, with  the  highest  concentrations   usually
       found in the tributaries and harbor head.

DETERMINING METHODOLOGIES FOR SETTING PRIORITIES WITHIN THE HARBOR

     It was very difficult for the harbor workgroup to determine
goals for  the  harbor.   It was also very  difficult for  them  to
determine the  best  way   to  set  priorities   within the  harbor.
Should this be  done by pollutant,  by source, by exposure,  or  by
magnitude or type  of  effect  on  biota,   or  some  combination  of
these? The entire  budget  for  the study could have  been  spent  on
improving methods  for  setting priorities, or on obtaining more
data, to  enable  us to  use  more  sophisticated  priority-setting
schemes.

     We  already  had made  a  relative  ranking of  point  and non-
point sources.  We  did not* however, know which of the pollutants
in ambient water  (monitored  by IEMP and other institutions) were
most .likely to cause adverse effects on biota.  There were sever-
al priority-setting methods  available  or under  development for a
pollutant-based approach.  The harbor workgroup, therefore, inves-
tigated  four methods, each of  which would address individual pol-
lutants or classes of pollutants.  The  first three were thought
to be  relatively  inexpensive,  as they  relied on existing data  to
set priorities.  14,15  The fourth, laboratory and field bioassay
and bioaccumulation studies,  was investigated  to determine   if
this generally  more expensive  approach  to setting control priori-
ties might  be  the  only   scientifically  acceptable  one.16,17   in
addition,  the  workgroup  wanted a  review of   available  literature
that would pertain to the study area.   Each method  of  priority
setting  is   mentioned  below.   The  harbor   workgroup eventually
chose  indexing  as  the method it  would use in Phase  I.  They
decided  to defer  any  use of  the other  methods  until Phase  II.


                               VII-10

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      INDEXING:  We  developed  this  method  to  directly  compare
existing pollutant  concentrations  in ambient water  to generally
applicable  reference  values,  specifically  EPA's  chronic  water
quality criteria for saltwater and  freshwater,, and EPA draft sedi-
ment  threshold  contamination concentrations.

      ECOLOGICAL SCORING:  A  common means  of scoring likely harm-
ful ecologic  effects  from a  given pollutant  on a  given species,
is to measure its LC^Q (concentration of  the pollutant  at which
10% mortality of  the  species  occurs  within a specified amount of
time).  LCso's  are  also  commonly  developed.   Ecological scoring
uses  the  same data used  in  developing  the lethal  concentrations
to generate  an  entire dose-response  curve,  thus   enabling  the
analyst to  estimate the mortality  rate  for a species from a cer-
tain  pollutant  at any concentration.

      REFERENCE  ENVIRONMENTS:   This  is  another  approach  under
development at  EPA; it compares ambient  conditions in different
"reference" areas (of similar physiography) in order to determine
which of  a  wide variety  of  pollutants  or  pollutant classes  are
most  responsible  for environmental deterioration in  a given study
area.

      BIOACCUMULATION AND  BIOASSAY  TESTS:   This  entailed, a review
of the technical approaches to bioassay and bioaccumulation tests
as well as  a  literature  review  of  all studies known to have been
conducted in  recent years in the Baltimore Harbor  and Chesapeake
Bay.  Bioaccumulation  tests  measure the degree to  which certain
pollutants bioaccumulate  in  biota  such as  fish.   Bioassay tests
measure the toxicity of the entire mixture  of pollutants the fish
or other organism is exposed to.   It is, thus, a measure of toxi-
city.  Additional work, however must be performed to isolate the
individual pollutants of  greatest  concern. 1*>, 17

      The indexing method appeared to be  simple, easy  to replicate,
and would provide  a  good first^cut  ranking of pollutants.   In
addition, it  was  based  on EPA-approved  water quality criteria or
draft criteria.   The  harbor  subcommittee,  therefore,  chose this
method as the priority-setting  tool  for Phase I.   Results of the
indexing follow.

INDEXING

      The indexing  concept is  well established  in   environmental
work  — air indices,   for instance,  are  often  used to  rate air
quality in  general  categories such  as  good, fair,  poor,  or un-
healthful.  In  this case  the harbor subcommittee investigated the
use of indexing to  select pollutants for intensive study in Phase
II.
                              VII-11

-------
     Indexing can be  used  on measurements of the  concentrations
of contamination in  the  water  column,  sediments,  or  effluents.
Its advantage  is  that it  is  straight-forward  and  specific.   It
compares the concentration of a certain pollutant  to  a pollutant
reference value, or standard.   We used externally  supplied  refe-
rence values:   EPA1s  saltwater  chronic  criteria,  EPA  freshwater
chronic criteria, and  draft  EPA threshold contamination  concen-
trations.  EPA1s criteria  are reference numbers  which  are devel-
oped through  a  scientific  review  process,  thus  enhancing  the
validity of the scores.

     The basic methodology of indexing  is to derive  index values
as a  simple  ratio  of  observed  values   to  reference  values:

                    INDEX NUMBER = OBSERVED VALUE
                                   REFERENCE VALUE

     Theoretical and Practical Considerations

     Indexing is an attractive way of sorting data, screening for
potential impacts,  and  setting priorities  among  pollutants.   It
enables comparison  of  individual pollutants, based  on potential
ecological  impact.   A  second  positive  aspect  is  that it .uses
standard EPA  approved  reference values.   A third  advantage  is
that it is  simple,  inexpensive, and is based on readily-available
information.

     Indexing has a number of limitations, which are  listed below.

     o Detection limit problems, changes of conditions over time,
       lack of data for particular pollutants, spatial variations
       over a study area,  definition  of values  of concern (mini-
       mum, mean, maximum),  and  similar problems  can detract from
       the  effectiveness of  the  approach.

     o Criteria  are available  for most of the common metals, but
       not  for  the wide  range of possible  organic contaminants
       (pesticides, other  industrial organics).

     o EPA  Water Quality  Criteria have  been developed to repre-
       sent typical national conditions,  not specific  local con-
       ditions.  They  are  based on  setting levels at  which  a
       particular  sensitive  species can  survive --  if  that
       species  is  not  present  in a particular locale,  the crite-
       rion must  be adjusted  to a level  that  protects whatever
       species  is  most  sensitive in that area.

     o Since  the EPA Water Quality Criteria were  first  introduced
       they have  been  modified  fairly  extensively.  Changes  in
       values of the criteria can easily change  the policy results
       of an  indexing  effort.
                                  VII-12

-------
      o Competition  among  species and food  chain  effects  are not
        well  represented in the criteria's derivation.

      o The Baltimore Harbor  environment is estuarine.  The sali-
        nity  varies  widely over time and in different areas of the
        harbor.   EPA,  however has only  developed  salt  water and
        fresh water  quality criteria-.  We  judged salt water qual-
        ity criteria to be more  appropriate  because the majority
        of the   species   were  either  salt-water  or  anadromous
        species  (Anadromous means the species spends  most of its
        adult life in salt-water  but spawns  in  fresh or brackish
        water).

      o Consideration of physical factors  like water temperature,
        availability of spawning  areas,  adequacy of  canopy cover,
        turbidity and similar  habitat   factors  is  not  possible
        within indexing.   Indexing also  does  not address "conven-
        tional"  pollutants — such as nutrients, dissolved oxygen,
        and salinity.

      o Interactions  among multiple  toxic  pollutants  cannot  be
        assessed.  Even  if all  contamination  levels are  within
        permissible  limits, the cumulative  effects may still pro-
        duce  adverse  reactions.

      o Even  if  a species  can theoretically survive  in a particu-
        lar environment, it may avoid that  environment  in prefe-
        rence to less contaminated ones.  There may therefore  be
        no guarantee  that action based on index values will result
        in any increase in local populations  of desired species.

RESULTS OF INDEXING EXERCISE

      Indexing was used in several  ways  to set  priorities.   We
used  indexing to rank metals in ambient water  in the harbor and
the tributaries  and the sediments.  We also used  it  to  compare
ambient water in the  harbor with  that in  the  Chesapeake  Bay.

Metals  in Ambient Water

     The first  set of results pertains to toxic metals in ambient
water  in the harbor.  We used the two data sets which were avail-
able  for toxics concentrations  in ambient  water.  We  used them
separately rather than averaging  them together  because they were
devised in different  ways.   For  example,   they  were  collected
several years apart,  using  different  monitoring,  sites.   Table
VI1-3 provides  the  range  of  values, by pollutant,  for  each data
set.  One data set came from a study by Dr. Helz of  the Universi-
ty of Maryland,  which was summarized in a report prepared by Tri-
dent,  Inc.,  for  EPA  in 1977 (the  Trident data set).  The IEMP data
were collected  in a monitoring  study performed  in 1984 (the IEMP
data set).
                              VI1-13

-------
                            Figure VI1-3

                           Baltimore IE HP
                     Baseline Results of Indexing
                     for Metals in Ambient Water
                         in Baltimore Harbor
                                                    8.0
    NICKEL
   COPPER
 CHROMIUM


      ZWC


  CADMIUM
DJ07

0.13
0.08

   £,

J04
fi TRDEHTDATA^
    .9
           J04
                                        -4-
                                             H
         0123456789
     Indexing Score = Ambient Vater Conc./EPA Ctronfc Saltwater Criteria (1989)
1 When sample concentrations were found to be less than the detection
 limit, they would range from zero up to the detection limit. This table
 provides the baseline case, using an assumption that undetected values
 are equal to half the detection limit. This assumption holds for both
 sets of data (IEMP and Trident),  (see p. VII-14 for explanation).

2Mean values for individual pollutants at 13 sites, from IEMP
 monitoring of Baltimore Harbor in 1984.

3Mean values from U.S. EPA, "Evaluation of the Problems Posed by In-Place
 Pollutants in Baltimore Harbor and  Recommendation of Corrective
 Action", Trident Engineering Associates, Annapolis, MD, 1977.

-------
     These monitoring  data were  used in  indexing,  as  shown  in
Figure VI1-3.   However,  for  the  IEMP data,  there  was some uncer-
tainty as  to  the  best  way  to  interpret  non-detected  values,
especially since  many  of the detected values  were  not far above
the detection  limits.  Various methods of  accounting for samples
below the  detection limit were  tried.   These  included  assuming
all samples  below detection were:  the detection  limit,  half the
detection limit,  or zero.

     The harbor  work  group felt  that the  second  approach above,
was the best to use for  indexing, as long as it was understood by
the group that  the actual situation could be more or less conser-
vative then  the chosen option.   Figure VII-3  shows the results,
assuming that  whenever  samples were  not  detected by  IEMP,  they
were averaged  in at half  the  detection  limit.   For  two metals,
mercury, and nickel,  both data sets  (IEMP  and Trident)  resulted
in scores  greater  than  one,  (i.e.  ambient concentrations  were
greater than the  EPA's chronic ambient water  quality criteria).
For lead  and  copper,  only  the  Trident   data set  resulted  in
concern.  For  zinc,  cadmium,   and  chromium,   neither  data  set
resulted in concern.

Sensitivity  Analysis Based on  Assumptions for Detection Limits

     The next  set of  results  consisted  of  sensitivity analysis
based on differing assumptions  for detection  limits,  using the
IEMP data.    The two alternatives to the preferred  approach  were
described on the proceeding page.  Results are provided in Figure
VII-4.  Using  the  most  conservative  (pessimistic)  assumption
(when a metal  was not detected,  it was at  the detection limit),
four metals, mercury,  nickel,  copper, and  lead, were of concern.
The more optimistic assumption  (regarding all samples below detec-
tion limits  as  zero)  provides  a  lower  bound to   the  expected
impact.  Using  that assumption, the  IEMP data  shows only mercury
to be of concern.

Metals in the Tributaries

     The third set of results for indexing was based on levels of
metals in the  tributaries to the  harbor  compared  to  EPA fresh-
water quality criteria.  The source of this data on metals in the
tributaries, is  the Jones  Falls  National  Urban Runoff  Program
Data.8  Monitoring  data  (and  criteria  were available  for  five
metals.  The results are provided on Figure VI1-5.   Again,  mer-
cury is of  greatest concern,  although  all the metals monitored
were of concern.   (Two of these metals,  chromium and zinc,  were
not of concern  in ambient water  in the harbor.  A third, lead,
was of concern  in ambient water  in the harbor according to one
data set but not the other, as  shown in VII-3.)
                              VII-14

-------
                       Figure VII-4

                      Baltimore IEMP
                               /••
     Sensitivity Analysis Based on Varying Assumptions
  Regarding Detection Limits Used in Indexing for Metals in
            Ambient Water in Baltimore Harbor
                                             1
                  2345678
                 Indexing Score =  Ambient Concentration/
                   EPA Saltwater Chronic Criteria (1985)
1
 Based on average ambient water quality, from IEMP monitoring
 of Baltimore Harbor in 1984

    dl = dl/2. This is the baseline option. Where monitoring
    values were less than detection limits, we used half the
    detection limit

    dl = dl.  This is the most pessimistic option. Where moni-
    tored values were  less than detection limit, we used the
    detection limit.

    dl = 0. This is the most optimistic option. Where monitored
    values were less than the detection limit, we used zero.

-------
                        Figure VII-5

                       Baltimore IEMP

                   Results of Indexing for
          Metals in Tributaries to Baltimore Harbor
    Mercury
       Lead
16.7
     Copper
Chromium (VI)
               2468    10   12   14   16
              Indexing Score = Estimated Ambient Water Coney
                 EPA Chronic Freshwater Criteria (1985)
  18
Source of monitoring data is the Baltimore Regional Planning
Council, "Jones Falls Watershed Urban Storm Water Runoff
Project," Interim Report. Baltimore, MD, 1982.

-------
                              VI1-14

Metals in the Sediments

     The fourth set of results for indexing, provided in Figure
VII-6, was based on levels of metals in the  sediments  in  the har-
bor and  the  bay.  The  source of  the  data  for  sediments  was  a
study which G.R. Helz published in  1976,, and which is  referenced
in "National Perspective  on  Sediment  Quality",  EPA,   1985.  This
report also provides the "threshold contamination concentrations"
which we used as  criteria for comparison with ambient concentr-
ations of metals in the sediment.

     As Figure VII-6 shows,  the  indexing score for chromium  was
higher than the  scores for  other metals in  the harbor.  It  is
also interesting to note  that the  score  for  chromium  in  the har-
bor was higher  than that  for  chromium  in  the  bay.   This makes
sense because there has been  a  great amount  of chromium waste
deposited in and  around  the  harbor area over  the last  several
decades.

Comparison of  Metals in the  Harbor with Metals  in the Bay

     The fifth set of  indexing results compared  levels of pollu-
tants in the eleven IEMP  monitoring sites in the harbor  with  the
two IEMP monitoring sites in the  bay  (Figure VII-7).  This data
set showed copper, nickel, and mercury to be above water quality
criteria at these  two  sites in the bay.  (See Figure VII-2  for
their locations.)  This data set  was too small to be  conclusive,
and it  was  not evaluated statistically.  Nevertheless.,  it   was
interesting that  not  all  of  the pollutants  were higher in  the
harbor;  copper was higher in the  bay.   It  might be  worth inves-
tigating this  further  to  determine   if this  is a  consistent
occurrence and if so,  what its causes are.

Summary of Indexing Results

     Table VII-4 provides  a  summary of the  indexing  results pro-
vided in the last  five  figures.   The members  of  the harbor work-
group used  this  information  to  reach  their  final  conclusions.
They were concerned about the level of  mercury,  nickel,  copper,
chromium, lead and zinc.

     They also  concluded  that  indexing did  not  result in  any
individual metals  ranking  far  enough above  the  others,  for aqua-
tic ecological impact,  to justify singling out one or a few metals
from the above metals  for Phase  II study.   Therefore, given  the
similar results for the different metals and the uncertainties in
the data, they  felt that additional work should be  performed in
Phase II on the  six metals mentioned  above.  They decided to  use
eco-scoring to perform  this  analysis  in Phase II  because  it  was
the best developed of the methodologies and had the most support-
ing data.

                              VII-15

-------
                                Figure VII-6

                              Baltimore IEMP


       Results of Indexing for Metals in Baltimore Harbor Sediments
    Chromium
      Copper
       Lead
      Nickel
                                                  Chesapeake Bay

                                                  Baltimore Harbor
           0    2    4
10   12    14    16    18    20
         Indexing Score - Ambient Sediment ConcVDrafl EPA Sediment Threshold Cone. Value
Source of sediment data is a study by Dr. Helz'of the University of
Maryland, which was summarized in a report prepared by Trident
Engineering Associates, Inc. for EPA in  1977.

-------
                              Figure VI1-7

                            Baltimore IEMP
          Comparison of Ambient Water Quality Indexing Values
                for IEMP Harbor Sites with IEMP Bay Sites
    Mercury
                                                     Chesapeake Bay

                                                     Baltimore Harbor
                   123       4        5
                   Indexing Score = Ambient Water Concentration/
                      EPA Chronic Saltwater Criteria (1985)
Source of data is the IEMP monitoring performed at thirteen sites in and
around the Baltimore Harbor in 1984.

We used the eleven IEMP sites in the harbor and compared these to two
IEMP sites in the bay. (See Figure VII-1  for map of monitoring sites.

-------
                                       Table VII-4
                                       Baltimore IEMP

                  Comparison of Index Values For Harbor Priority-Setting,
                      Using Different Types of Indexing Techniques *
         Ambient Water Quality
            Harbor
         Trident     IfiMD
         '  Data1    Data2
   Ambient Water
Quality-Tributaries
Ambient Sediment   Ambient Sediment
Quality-Baltimore  Quality-Chesapeake
     Harbor             Bay
Zinc
Nickel + +
Mercury 0 O
Lead + °
Copper O +
Chromium ° °
Cadmium ° °
>
N/A
O
O
0
+
N/A
+ N/A
+ +
N/A N/A.
0 N/A
O N/A
0 +
N/A N/A
 O  Index value greater than 2.
       Criteria)
 +  Index value greater than 1.
 0  Index values less than 1.
N/A Not Available.
(Ambient values are more than twice the level of EPA

(Ambient values are greater than EPA criteria)
(Ambient values are less than EPA criteria).
1.  See Figures VI1-6 to VII-10 for a presentation of the indexing scores and the
    sources of data used to generate this table.

2.  Assumed undetected monitoring values were egual to half the detection limit.
    figure VII-7 and p. 14 for further explanation.
                                                 See

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Limitations of Indexing

     Recognizing the  limitations  of ^indexing  is  important.   A
number of  limits  to  indexing  were outlined  earlier in  general
terms.  One  limit to  the usefulness  of indexing  for the  IEMP
study was that IEMP did not monitor arsenic, cyanides,  and selen-
ium.  Also,  the  valence states of  metals,  particularly  chromium
and mercury, can  significantly affect  the  resulting  toxicity and
bioavailability for those metals,  and this method does not diffe-
rentiate between valence states.   This list of six metals, there-
fore, is merely  a list for possible concern.  More  work  will be
done in  Phase II  to further  evaluate the  metals  on the  list.
                               VI1-16

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                        FOOTNOTES
1.  Koo,  T.S.Y.,  Pfitzenmeyer H..T.',  Dovel, .W.L.,  Wiley,  M.L.,
    Lippson, R.L.,  Miller,  R.E.  A Biological Study of Baltimore
    Harbor,  College Park, Maryland, University of Maryland Center
    for Environmental and Estuarine Studies, Special Report No. 6,
    1975

2.  Krebs,  Charles  J.,  Ecology:   The Experimental Analysis of
    Distribution and Abundance, Harper and Row, 1972.    """^

3.  Odum, Eugene P., Fundamentals  of Ecology,  W.  B.  Saunders and
    Company, 1971.

4.  EPA Discharge Monitoring  Reports collected  for  the National
    Pollution Discharge Elimination System,  for 1983-1985, except
    1982 for Bethlehem Steel.

5.  Memo  to  EPA from  Versar,  Inc.,  Baltimore Non-Point Sources,
    November 17, 1983.

6.  Memo  to  EPA from  Versar,  Inc.,  Baltimore Non-Point Sources,
    January 13, 1984

7.  Personal  Communication between  Hope  Pillsbury  of  EPA  and
    John Veil  of  Maryland  Office  of  Environmental  Programs,
    October 1986.

8.  Baltimore  Regional  Planning   Council,  Jones Falls Watershed
    Urban Storm Water Runoff Project,  Interim Report, Baltimore,
    Maryland, 1982.

9.  Memo  to  EPA from  Versar,  Inc.,  Modeling Toxics in Baltimore
    Harbor,  November 13, 1983, and subsequent discussions of this
    memo by IBMP.

10. The source of the proceeding paragraphs on  aluminum  is personal
    communication between  Catherine  Crane of EPA and Dr.  David
    Correll, Assistant Director of the Smithsonian Research Center
    in Edgewater, Maryland, in Fall, 1985.

11. EPA,  Office of Water  Planning  and  Standards,  Evaluation of
    the Problem Posed by In-Place Pollutants in Baltimore Harbor
    and Recommendation of Corrective Action,   Trident Engineering
    Associates, Inc.,  Annapolis,  Maryland, September 1977.

12. Discussions were held between IEMP  staff  and Dr.  Boicourt of
    the University  of  Maryland,  Dr.  Biggs  of the  University of
    Delaware, and Mr.  DeMoss of EPA, in 1984.

-------
13. Memo to EPA from Versar, Inc., Final Monitoring and Analyti-
    cal Plan for Baltimore Harbor/Chesapeake Bay - Phase I    "
    Activities, August 3, 1984'

14. Memo to EPA from Versar, Inc., Baltimore Harbor Data Report,
    November 23, 1984

15. Briefing  packages prepared  for IEMP  by  Versar  Inc.,  on
    Indexing, Ecoscoring,  and Reference Environment Analysis,
    dated November and December, 1985.

16. Memo to IEMP from Versar, Inc. Draft Overview of the Use of
    Bioassay and Bioaccumulation Studies for Water Quality
    Evaluations,1985.

17. Memo to IEMP from Versar, Inc. Review of Biological Studies
    Conducted  in Baltimore Harbor and Chesapeake Bay,  1985.

18. Bolton, H.  Suzanne et.al., National Perspective  on Sediment
    Quality, U.S. EPA, May 10, 1985.

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               CHAPTER VIII




COMPLETION OF THE PRIORITY-SETTING PROCESS

-------
          VIII. COMPLETION OF THE PRIORITY-SETTING  PROCESS

     This chapter discusses how the Management  and  Technical  Advis-
ory Committees pared  the  10  issues,, to  five topics  for Phase  II
study.  It also describes  the  reevaluation of metals-related issues.

    After the  subcommittees  had  made  their   recommendations  on
issues for further  study,  the full TAG decided to  undertake three
further/ interrelated  efforts  before   proceeding   to  Phase  Two.
First, it wanted  to  reduce the number  of issues in order  to avoid
overextending the  analytic  resources   of  the  study.   Therefore
it developed a set of secondary criteria to evaluate the ten issues
for policy and pragmatic  reasons.  Second, to help  the  TAG members
be more  informed  about  the issues,  the  subcommittee members  with
the assistance of EPA staff  developed workplans  for each  of the
study topics.  This provided the information necessary to apply the
secondary criteria, determine the budgets, and  then of course to do
the work.

    The third  effort  involved the umbrella  topic  of toxic  metals
in the  environment.   Upon closer  scrutiny,  the TAG  realized  that
the issue was  too broad;  it contained too many  issues  that  needed
to be ranked  in  importance.  Thus,  the  TAG decided  to reevaluate
these numerous issues against the primary criteria to  arrive  at a
smaller set of issues dealing with toxic metals in  the environment.
These would then also be  evaluated against  the  secondary criteria.
We discuss this  second  and  separate priority-setting  process for
metals later in this chapter.

REDUCING THE NUMBER OF ISSUES FOR STUDY

    As discussed  in  Chapter  IV,  the TAG  chairman asked  the  sub-
committee chairs  to  recommend more  issues  than the  project would
have the resources to study.   Once these  were  identified,  the full
TAG would narrow  the number  through the  application of secondary
criteria by  consensus.   Discussion would  focus  on the  social and
economic importance of issues  and on trade-offs between human health
risk and ecological impact. This  latter type of trade-off was never
made explicitly because the  list  was pared down  sufficiently using
other criteria.

The secondary criteria were:

1)  Probability  of  making  a  significant   contribution to local
    environmental management  through  the  Phase II  study  of  the
    issues.

2)  Lack of duplication with existing analyses or control programs.

3)  Technical  and political  feasibility  of implementing  controls
    for each issue studied,
                              VIII-1

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4)  Feasibility of performing the analysis within the time and fiscal
constraints.

     The TAG chose  this strategy because  of  its conviction that it
was inappropriate, and probably infeasible, to develop a a quantita-
tive, scientifically-based  approach to  compare priorities  across
the reference  categories  of human health, ecological,  and ground-
water.  The TAG judged that its chances of success would be greater
if it concentrated its debate on tradeoffs in  the context of specific
issues rather  than on abstract arguments about whether human health
is more  important than ecological protection  or the integrity of
groundwater.

     The TAG  was  also aware  that the  decision  to  create  three
subcommittees, each  responsible for setting priorities among  the
issues in a  reference category, would virtually  guarantee that at
least one health,  ecological,  and ground-water  issue  would emerge
as Phase  II  study topics.  Furthermore,  since  each member  of  the
TAG had a personal  and institutional  interest in one of  the study
areas (health,  ecology,  or  ground-water),   the  creation  of  the
subcommittees  formalized  existing  interests.   Nevertheless,  the
implicit understanding  that at  least  one issue  in each  category
would "survive" into  Phase  II  was  an  important  element in the pro-
cess of building  a consensus.

REDUCING THE NUMBER OF ISSUES FROM TEN TO SIX

     In practice,  further  reduction of the  total  number  of issues
proved relatively easy because of  the considerable overlap among
the study topics  recommended.  As Figure  VIII-1  shows,  all three of
the subcommittees  recommended  conducting  further work on  metals
in the  second phase  of  the  project.  The remaining  ecological
problems, the  bioaccumulation  of  toxics,   and  sediments  in  the
Harbor as  a  source  of  water  pollution,   were  combined  into  a
single study  topic  encompassing  Harbor  pollution.   Finally,  two
of the health  issues  recommended  for further  work,   benzene  and
the other  toxics  in  air,   were   collapsed  into  a  single  study
topic.

     Because of these overlaps, the original ten  issues  collapsed
into the  six topics listed in Figure VIII-1. This number  was near
the target implicity set  by  the  Management  Committee  and  the  TAG
when they first conceived  the priority-setting exercise  (see Chapter
IV).  Thus the full TAG did not  need to  eliminate any study topics
from those recommended by the subcommittees.
                              VIII-2

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                                              Figure VIII-1
                                  Flow Chart of How the TAC and the Workgroups
                                  Pared down the List of Issues from Ten to Five
                10 Issues
Human Health Risk Subcommittee

     Benzene
     Toxic Air Pollutior
     Trihalomethanes in
          Drinking Water
     Metals in Air-
     Indoor Air Pollu!

Ecological Impact Subcommittee

     Metals-
     Sediments
     Bioaccumulation
           Toxics in
           Aquatic Organises
                                  Combine and
                                  Redefine to
                                  6 Issues
      Air Pollution
Trihalomethanes in
Indoor Air Pollution
                                 Metals in the
                                     Environment

                                 Harbor
Ground-Water Resourced/Carnage Subcommittee
     Metals in Ground'
          Water
     Underground Storage
          Tanks
Underground Storage
     Tanks
                         Apply Secondary
                         Criteria
                                                         Tonic Air Pollution
                                                         Indoor Air Pollution
                        Metals in the
                             Environment

                        Harbor
Underground Storage
    Tanks
                           Redo
                           Primary /Secondary
                           Criteria for Metals
                           Resulting in Final
                           List of Issues	

                           Tonic Air Pollution
                           Indoor Air Pollution
                                                                                    Underground Storage
                                                                                       Tanks
  1\Continued in Phase II for comparison, but not for further study

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 APPLYING THE  SECONDARY CRITERIA

     After  reducing  the number  of study  topics  to six,  the  full
 TAG  formalized  and  applied  a set  of  secondary  criteria  to each of
 the  remaining issues. With  the explicit elaboration of  the secondary
 criteria, considerations  of  policy  and   feasibility  entered  the
 priority-setting process  for  the  first   time  in  a  formal  way.

     The use of  the secondary criteria was not, of course, the first
 time that policy  and feasibility  considerations had played a  role
 in shaping  the  study.   In developing  boundaries for the  study area
 at the  outset of the project and  in deciding to focus  on certain
 classes of  pollutants,  the  project's  managers were  making implicit
 policy decisions.  For instance,  worries about the analytic feasibi-
 lity of  the  study  led  to  the  decision  to  focus  on  a  relatively
 small geographic area.  Similarly,  considerations of the probability
 of making a significant contribution to local environmental manage-
 ment were largely responsible for the decision to exclude convention-
 al air  pollution  from the  IEMP.   At this point in  the  process of
 setting priorities,  however,  practical  considerations  began  to
 replace scientifically-based analysis  in determining what  to study in
 Phase II.

     Considerations of policy and  resourceis  were  also  important in
 the  discussions  of  the  TAG and  of  its  subcommittees  during  the
 initial screen.  Throughout  the  first phase of the  IEMP,  both the
 TAG  and the  Management  Committee  were careful  to  insure  that  the
 project did  not spend  its  time and  effort researching  issues to
 which it could  not  reasonably make a  significant  contribution.   In
 particular,  the  committees  wanted to concentrate  on topics  that
 could be analyzed within  the resource constraints  of  the  IEMP and
 that could be addressed by the state and local governments partici-
 pating in the study.  The committees also wanted to avoid duplicat-
 ing  the efforts of other analytic studies.

     Many issues,  such  as  pathogens  in   septic tanks,  never  made
 the  initial  screening list  simply because  neither  EPA nor  State
 and  local officials  believed that the IEMP study  of  them  could
 contribute meaningfully to  their understanding.  Some issues  such
 as pesticides,  were  rejected as  study  candidates during  the  sub-
 committees'  meetings because existing data (such as .on  exposures)
 were so poor  that the IEMP had no  reasonable prospect  of analyzing
 the problem in  a meaningful  way.  For the most part,  however,  the
TAG deferred  consideration  of  secondary  criteria until  completion
of the subcommittee work.
                              VII1-3

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     These "secondary  criteria"  of pragmatic  considerations  of
time and resources were formalized about  the  time  that  the  three
methodological subcommittees concluded  their  deliberations,  and
emerged with a list of. ten issues.   The criteria  were  not  applied
until the TAG reduced the number of issues to  six,  as previously
described.

     Most of the secondary criteria are straightforward  and  self-
explanatory.  The criterion of  "political feasibility of  control,"
however, deserves  some special  attention.   Primary management
responsibility for the IEMP  rested  with state and  local  govern-
ments, who did not  wish  to spend time analyzing issues they had
no reasonable prospect of  controlling.  Some  environmental  prob-
lems, such as acid  rain,  are simply unamenable to  state or  local
control because  they  entail interstate transport  of  pollutants.
As it  turned out,  no potential  topics  were  excluded  from the
study on the basis of this particular criterion.

     Use of the  first criterion,  probability of making a signifi-
cant contribution  to  local environmental  management,   included
possible duplication  of   existing  or  planned programs  and the
degree to  which  the problem could  be characterized  as  national
rather than site-specific.  Problems which were national in scope
and which were not  expected to be different  in Baltimore  than in
the nation as a  whole were considered poor candidates for  further
work.  The  opportunity to  participate in a  study conducted by
EPA's Office  of  Research  and Development  made  indoor  air  an
important exception.  One  of the  six  topics  then under  consider-
tion for  study   in  Phase  II,  trihalomethanes  (THMs)  in drinking
water, was deemed by  the  TAG to  perform poorly in terms of  these
criteria.  As explained in Chapter IV, THMs are present in virtu-
ally all  chlorinated  surface  water  used  for  drinking water in
this country, or about half of  the total drinking water.   They
are present because they are a  by-product of chlorination required
to kill pathogens in the water.

     Baltimore's water supply is  well within the  federal limit for
THMs and the federal limit  is  currently under reconsideration by
the EPA.   The  committee   felt that  the   exposures,  risks, and
controls for THMs are well understood  for purposes  of  risk manage-
ment and  that there was  a  low probability that  a  Phase II  study
of this  issue would  make  a  significant  contribution to   local
environmental management.   Therefore  the  TAG  and MC  decided that
THMs would not be  a Phase II  study topic.   It was not, however,
dropped completely  from  Phase  II consideration.   The Management
Committee felt   that  the   relatively  well-characterized  health
risks from THMs  in  drinking water  could later be  compared  to  the
risks associated with the other Phase  II issues.
                             VII1-4

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      Use  of  the second and third criteria entailed consideration
 of  other  projects being  conducted  by federal,  state,  and local
 governments,  as well  as a rough appraisal of the extent to which
 conceivable  controls  for a particular problem  would  be feasible
 at  the  state or local level.   No study topics were eliminated on
 the basis of  either criterion because the studies could be struct-
 ured to enhance, rather  than  duplicate  existing State  or local
 efforts.

      Use  of  the fourth criterion,  analytic  feasibility,  was the
 most difficult.   For  obvious reasons, the managers of the project
 wanted  to concentrate their  attention and funds on problems that
 could be feasibly analyzed within budget  limitations.  Understand-
 ing what  analysis of  each issue was possible within those funding
 constraints,  and what the project  could hope  to achieve  on each
 possible  topic,  was  critical.  It  was also  virtually impossible
 to  do casually, without  a reasonably thorough  investigation  of
 available data,  possible monitoring  and  analytic  strategies,
 costs of various analytic schemes, and so forth.  For  this reason,
 the TAG decided to form workgroups  to develop work plans for each
 of  the  five study topics so it could directly compare  the options.

 DEVELOPING THE  PHASE  II WORKPLANS

      The TAG  drew  up  an  initial  set of Work  proposals  for each
 issue which  provided  the  objectives and purpose  of  the  study,
 alternative analytical  procedures,  and  the  expected  product  of
 the analysis.   These  were  then presented to the MC to help decide
 the merits of each study  topic.  The MC, however,  still  did not
 feel  they  had  enough  information  to  decide  which  of the  five
 issues  should  be studied  in  Phase  II (excluding,  for  the time-
 being,  THMs).   They  requested that  the TAC  provide  estimates
 of  funding  needs  for each  each element  of  the  work plan  and
 recommend an option for analysis.  Upon revision of the workplans,
 the TAC met   in  full  to  approve  the workplans  and pass  on  its
 recommendations  to the Management Committee.

      The TAC  created  five workgroups to  explore each  of the five
 topics.  It decided that these work  groups would  include represen-
 tation  from  institutions  outside  government.    Individuals  from
 industry, trade  associations,  and public interest  groups  served
 on  the  workgroups,  although they did  not become members  of  the
 TAC as  a whole.

     The TAC  chairman assured the  MC that each workgroup member
 would be  informed  that  no   workplan was  guaranteed  of  being
 performed, either in whole or in part.  Nevertheless,  he felt the
 added expertise  available  from the  additional  work  group members
 was worth  the risk.   The MC  then  decided that the  TAC  should
proceed with  formation  of workgroups  and  made suggestions  as
 to  appropriate organizations  to  contact.  Upon completion of the
 workplans, the  TAC  would meet in full to approve  the workplans
 and pass  on  its recommendations  to  the  Management  Committee.
                            VIII-5

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     The chairs  of  two  workgroups felt  that their  work plans
should be  better formulated before  they knew  which  additional
members of  industry or  public  interest  groups  would  be  most
knowledgeable and helpful  to  the project.  Therefore, they  only
added some  additional   governmental  members  at  this  stage  of
development of the  work  plan.   Others  members would be  added  as
as needed.

     For all the work plans, investigating  existing  regulations,
programs, and  plans was essential  to  ensure  that the  proposed
work supported existing  programs  and would help complement activi-
ties or  provide  resources  for  studies  that  would  otherwise
not be possible.

     During this time,  some, additional  technical  work was done  on
most of the issues to revise or supplement Phase  I analysis.  The
issue of metals required the greatest technical work.

SPECIAL ATTENTION GIVEN TO METALS IN THE ENVIRONMENT

     The TAG recognized  that the topic,  "metals   in  the  environ-
ment," encompassed  too   many   topics  whose  study  could  easily
exceed the  anticipated   resources  for  phase  II.   Narrowing its
scope meant  disaggregating the  issue  into  its  components  and
ranking these,  in  turn,  by the  primary  and  secondary criteria.
The TAG  formed a special  metals workgroup charged  specifically
with conducting this task.

     In the initial run-through  of the  priority-setting process,
described in  Chapter  IV,  the  issue had been  defined  in terms
of possible  sources of  metals released or potentially released
into the  environment.    In  this  second  round of  screening,  the
the workgroup  decided  upon  defining metals  in  the environment
in terms of their concentrations  in various receptor environments.

     This second run-through also differed from the first in that
new information  was available to the  workgroup  members.   They
now had indexing scores  for metals  in the tributaries  to Baltimore
Harbor.   (See  the discussion of  indexing scores in the discussion
of the Harbor  in Chapter  VII.).  Furthermore, unlike the first
round of  priority-setting,  EPA staff  now had  available to them a
model that  could provide  rough  estimates of  the  human health
risks to  individuals which could arise from potential  degradation
of ground-water  resources.

     The  metals  workgroup began  with  fifteen metals,  which are
listed in Table  VIII-1.  [A sixteenth was considered if one  takes
into account the separate evaluation of the two forms  of chromium—
tri- and  hexavalent chromium—that  are  commonly  found  in the
                           VIII-6

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 environment.] The  workgroup  members  chose  these  metals  on  the
 basis of  their  judgment  regarding  their  likelihood  of  being  a
 pollution problem.   They were drawn  from an  initial list of  129
 priority pollutants  (only a fraction  of which were metals) developed
 by EPA's Water Office.

                           TABLE VIII-1

            Metals Considered In the Phase I Screen by
               the .Baltimore IEMP Metals Work Group


                        Aluminum     Antimony
                        Arsenic      Barium
                        Beryllium    Cadmium
                        Chromium     Thallium
                        Lead         Copper
                        Nickel       Mercury
                        Silver       Selenium
                        Zinc


     After a perusal of the available data, the workgroup discovered
 that only the data on  nine metals  would  allow a limited evaluation
 against the primary  criteria.   For  the  other  metals,  the  little
 information that existed suggested that  they were unlikely to have
 significant impact in  any  likely scenario for  the  Baltimore  area.
 Also, there was no significant  source of these metals in the  study
 area. Given  its  limited  time  and  resources,  the  workgroup  was
 constrained to examine  only  those  metals for which there  was some
 minimally adequate data indicative  of  a possible  threat to  the
 environment.  Thus  the  metals  that  remained  under  consideration
 were aluminum,  arsenic, chromium,  lead,  zinc, cadmium,  mercury,
 copper, and nickel.

     The primary  criteria  for  screening  these  metals  remained
human health  risk,  ecological  impact,  and potential  for  damaging
 ground-water resources.

     The workgroup estimated  the human health  risk posed  by  these
 nine metals through  ingestion of  water  and  fish,  and inhalation
 of dust.  Because data on exposures for each metal differed greatly
 in kind and quality,  risk estimates  are not directly comparable.
Again, the workgroup hadi often to rely  on best judgement  in  deve-
 loping an assessment of the total risk  of each  through all  path-
ways of  exposure.    Furthermore,   it  had  to decide  the  relative
weight of actual  incidence of disease attributable to a metal  and
postulated risk of  disease  that  occurs sometime  in  the  future.

     Because no  new  data  became   available  for  this  round  of
priority-setting for  metals,  the  estimation  and relative  ranking
                             VIII-7

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of risk  through  inhalation  and  ingestion  of  metals  did  not
change.  These  estimates of  risk  are presented  in Chapter  V:
Human Health Risks.  As before, chromium appeared to be the metal
of primary  concern in the  air.  Only  lead presented significant
health risks through ingestion.

     The workgroup  was particularly  concerned  by  the  immediacy
•of the  public health  problem posed  by lead.   There  is  strong
evidence that  the health  of people  in the  study  area can  be
adversely affected  by lead  in  water  and  that  children are  now
suffering the  consequences  of lead  in household dust.   Although
there is  no  evidence  that  elevated  lead  levels  exist in  the
water supply,  two  conditions can  contribute high lead to  the
water faucet  or  fountain:  (1)  new  or replumbed  buildings with
copper pipe and lead solder or (2) older buildings with lead pipes.
Levels of lead  in tap  water,  especially in the  first few minutes
of flow have been found to exceed existing drinking water  standards.
In addition,  the  work  group had  data on actual  cases of lead
poisoning in children.  Each  year  roughly 150 hospitalizations of
children per year occur from  ingestion  of lead in household where
the  residences  had been painted with lead-based paint.   In 1985,
290  Baltimore City children were diagnosed as suffering from lead
poisoning.  [A  more complete  discussion of  the problem of lead
poisoning among children in Baltimore City  is presented  in Chapter
IV.] These  numbers could underestimate the actual  number of lead
poisonings  in' the area  because  of under-reporting.  On the other
hand, there  could also be double counting of lead poisoning cases
occurring to the  same child.

     The workgroup used the  ecological  indexing  system, explained
in Chapter  VII,   to identify metals which could  adversely  affect
the  aquatic  ecology of  the Harbor.    Figure VI1-6  showed that  the
highest scores  were for mercury and nickel in  the water  of  the
harbor.  Mercury, zinc,  copper,  chromium,  and aluminum were high
in the  tributaries.   High concentrations of  chromium  were found
in the  sediments.

     There  are  few data on metal concentrations  in ground-water.
Details are  also very scant  for  what  ground-water  resources  are
at risk  of  contamination  from  metals—especially  sources that
are  not  now serving  as  sources  of drinking water but could be
used in the  future.

      In the  absence of monitoring data,  the  workgroup used best
professional  judgement  and  an indexing scheme  (which we describe
in Chapter  VI)  to  identify  metals and their  sources  that could
pose significant   risks   to   ground-water  resources.    From   the
screening analysis,  the work group identified  eight significant
metal-related scenarios.  They also determined  the most practical
approach  for  studying each.  The issues and their  approaches  are
listed below:

     o  lead  intake  by  children  from   paint,   dirt, and   air


                             VIII-8

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         (testing and  evaluation of lead  abatement  techniques in
         the  study area);

      o  human  health  risk from  lead'intake  from lead-containing
         solder  in  drinking  water pipes,  in  areas  with  acidic
         water  and/or  new piping;

      o  health  risks  from metals such as  cadmium,  chromium, and
         arsenic through  ingestion of  locally harvested  finfish
         and  shellfish  (only  if  OEP  monitoring  data  suggests
         significant health risks);

      o  human health  risks from ambient air exposure to chromium,
         cadmium, arsenic and nickel;

      o  potential  risks to human health, and predicted  impacts
         to the  ground-water  resource,   from  arsenic  and  other
         metals  leaching into ground-water from municipal
         landfills;

      o  ground-water  resource damage  from chromium  leaching into
         ground-water  from the harbor area;

      o  impacts on  aquatic life  in  the  harbor  from  exposure to
         lead, nickel,  copper,  mercury in the  ambient  water, and
         these metals  and chromium in the sediments;  and

      o  impacts on  aquatic life  in the  tributaries  to estuarine
         waters  from leaching  of  aluminum and other metals  from
         soils.

      To  determine  the  extent  of  additional  work  the  metals
workgroup should undertake for  the  above issues,  the workgroup
developed and applied  the following secondary criteria  for judging
their  feasibility:  (1) whether the  issue is  being  addressed by
other  work  groups  in the  IEMP,  (2)  whether the issue is  being
considered by  State or  local governments, (3) whether the issue
is technically or politically feasible for study in the IEMP, (4)
whether  the  cost  of  studying  the issue is  too great, and (5)
whether  State or local governments will be able to effect controls
for any problems the  IEMP discovers.

     After applying the criteria, the workgroup found that
metals in the ambient air  and  impacts  on aquatic life  were to be
handled by  other  work  g,roups.   The  metals  workgroup  would  only
serve  in a coordinating role.   Lead  in drinking-water  was likely
to be  addressed by  the  State.   Monitoring for arsenic and other
metals in ground-water  or  aluminum in tributaries was  beyond the
resources of the IEMP.  Similarly, the IEMP  would not  be able to
do anything  practical to  resolve possible problems from  metals
leaching into ground-water from the harbor because  these ground-
waters are already severely degraded.  Thus, the workgroup decided
to recommend only lead intake by children  and  risks associated with
harbor fish for Phase  II.   The latter was dropped when Maryland's
                           VIII-9

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Office of Environmental Programs completed its analysis.1

PRIORITY SETTING THROUGH BUDGET ALLOCATION

     The final  stage  of  the  priority-setting exercise was  to
reconcile the workplans proposed by the  five  workgroups  with the
limitations of the IEMP budget.  The workgroups proposed  work for
Phase Two  that  would  have  cost  about  two  and  one-half  times
as much as the project had to  spend.  Deciding  where  to  cut back
the workgroups'  requests,  a  process which  occupied the  TAG for
three months, became one  of  the central  priority-setting devices
for the study.  In deciding how much to  cut each  budget, the TAG
as a whole was  in effect  setting  priorities among the  problems
to be analyzed.

     Each workgroup prepared work plans  for three budget levels,
asking in most  cases for the  highest  level of funding  from the
TAG as a whole.   Although decisions were again made by consensus,
the meetings at which  the  resources were allocated were  somewhat
more contentious than  most of  the  TAC's  other meetings.   The TAG
tried during these meetings to  use other forms of priority-setting
as well.  Several  TAG  members  felt that  the  overall budget was
simply inadequate to undertake analyses  of all  five  issues and
wanted to  eliminate  one  or  more entirely.   The  TAG could not,
however, agree  on  which  might be  eliminated.  Compromises were
made on  funding levels for  projects  and through  extending work
periods.

     Finally, the budget recommendations and the study alternatives
were presented to the MC for their review  and approval. It discuss-
ed the pros and cons of each study at length,.particularly  focus-
ing on the need to avoid duplication with existing  programs.  It
also discussed  the  possibility  of  omitting  one  study  from the
list.  It  took  two meetings for  the  MC  to decide  to accept the
TAC's recommendations  on  the issues and  the  funding  allocations
and to approve the work plans.  These work plans are presented in
Chapter IX.  They comprise the blueprint for the  second phase of
the Baltimore IEMP.
                            VIII-10

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1.   OEP found  levels  of metals  in fish  were below  FDA limits.
                           VIII-11

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     CHAPTER  IX
PHASE II WORK PLANS

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                      IX. PHASE II WORK PLANS
     In Chapter IV  and  the  last  chapter,  we described how the MC
and the TAG  set priorities  among the 32  issues  that  the  TAG had
identified to be of possible concern in the Baltimore study area.
In this  chapter,  we present  the work plans  of the  five issues
that the MC  chose  to be the focus of more  detailed  analysis and
assessment in Phase II of the Baltimore IEMP.

     The work plans  are not  intended  to be  detailed,  technical
blueprints for how the selected issues are to be studied in Phase
II.  In  general,  they  provide  only the  general  scope  of  the
projects and summarize  the goals  and  the analytical approaches.
More detailed plans were developed separately.


SUMMARY OF WORKPLANS FOR PHASE II

Issue #1: Air Toxics

     Ambient (outside air)  monitoring data for various pollutants
suggest that air toxics may pose a threat to  public  health.   Air
toxics may also transfer  to other media,  such as surface  water
(e.g.,  the  transfer of metals  from  the  air  to  the  Harbor).
Because of their  health risk  and the  appropriateness of  their
examination  using IEMP methodology, TAG has  chosen  the  issue of
air toxics for study in Phase II.

     The Technical Advisory  Group has identified the  goals of the
workplan for air toxics to be:

     o  Estimate ambient air concentrations of selected air toxics
        which result from emissions  from  both point  (industrial)
        and non-point (area)  sources.   A particular  emphasis is
        upon identifying possible  "hotspot"  exposure,  that  is,
        areas where  emission plumes may overlap resulting in higher
        than expected concentrations  of  certain pollutants.

     o  Analyze  associated risks  to human health and  the environ-
        ment. This  will entail identifying and quantifying (where
        possible)  risks to human health  or the  environment  from
        ambient  concentrations resulting  from air emissions  and
        identifying  the sources that  are significant  contributors
        of  risk.

     o   Analyze  and develop of control  strategies to  reduce the
        adverse  health   effects   from emission  of  selected  air
        toxics.
                               IX-1

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     There are three  major tasks  associated with  these goals:

     (1)  estimate ambient  levels  of  selected  pollutants.   For
         this purpose,  we will  use widely used ambient  air dis-
         persion models and   data  on'  industrial  emissions from
         the Maryland  Office   of  Environmental  Programs   (OEP)
         Science and Health Advisory Group's  Hazardous  Materiials
         Survey.   We will also estimate  the  contribution to
         ambient levels of certain pollutants from  area  sources,
         such as transportation  vehicles  and dry cleaners.  The
         pollutants will include volatile  organic  compounds and
         metals, selected on the basis of  their chronic  toxicity
         and their likelihood  of being  present in the  ambient air
         of the Baltimore study area.

     (2)  develop quantitative  estimations of  risk  from  ambient
         exposures to  the  selected  toxics   and  to   use  these
         estimates to  identify  the pollutants and  their  sources
         for which control strategies  will be developed.

     (3)  analyze and develop control strategies  for point and area
         sources, taking into account  the potential for pollutant
         transfer across media.   The  analysis  will include  the
         estimation of  costs  and  of  the  reductions  in risk  of
         alternative control strategies.

     A related task is overseeing,  along with the indoor air work
group,  the  Total Exposure  Assessment Methodology  (TEAM)  study
that will  be  conducted  in the Baltimore  study area by  EPA's
Office of  Research  and Development.   Oversight will  involve  re-
viewing the  study  design and  objectives,  coordinating  with  the
MC and State  and  local agencies  with  regard  to  publicity  and
selection of geographic sites within the Baltimore study area for
monitoring, and  recommending   pollutants  for  inclusion  in  the
study.   Ambient  monitoring  data generated as  part of  the TEAM
study will  serve to corroborate the air  toxics  work  group's  air
dispersion modelling estimates.  Conversely,  the  air  toxics work
group's air dispersion  modelling results will  be used in inter-
preting the results from the TEAM study.

     The goals of the TEAM study are:

       0   Apply  "modified" TEAM methodology to Baltimore to esti-
          mate exposure of  Baltimore  area residents  of  specific
          geographic areas to selected volatile  organic compounds;

       0   Compare  modeled  concentrations  with  measured ambient
          levels for selected volatile organic  compounds;

       0   Compare indoor  concentrations, outdoor concentrations,
          and  personal exposures.
                               IX-2

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 Fixed monitors  will allow comparison of  indoor  and  outdoor con-
 centrations of  selected pollutants  and the contribution  of out-
 door levels  to  indoor  concentrations.   Volunteers  will  carry
 personal monitors to permit estimation of total personal exposure
 to pollutants as  the person  goes  about his  or her daily affairs.

 Issue #2:  Indoor Air Pollution

     The TAG and the MC chose the issue of indoor (i.e., residen-
 tial) air pollution for the following reasons:

     o  Data from other cities  suggest that  indoor pollution may
        pose significant risk to human health.

     o  There is  little local data  on whether  indoor  pollution
        is also a problem in the Baltimore area.

     o  Resolution  of  the problem,  if  there  is one,  is likely to
        cut across  a  number  of government agency lines and thus
        be particularly appropriate for an IEMP project.

     People spend the majority of their time indoors in resident-
 ial, commercial, and  office  buildings.  Thus  even  though indoor
 air pollutants may be present at very low levels, they may never-
 theless make  a  significant  contribution to   personal  exposure.
 Indeed,  those groups of individuals most at  risk from the adverse
health effects of toxic substances,  such as  infants, young child-
 ren, the chronically  ill, and  the  elderly,  spend even  greater
 amounts of time indoors.

     A number of factors, such  as measures  for increasing energy
 efficiency, cleaning  products,  synthetic and  natural   building
 materials,   unvented heating  and  cooking appliances, and pesti-
 cides,  combine to increase the  likelihood of  exposure  to a mix-
 ture of   indoor pollutants.   Many  of  these  pollutants  may  be
present at levels greater than for  those  currently  controlled by
ambient air quality  standards.   Yet the health  effects of expo-
 sure to such mixtures is largely unknown.

     The goals of the workplan are:

     o Learn  more   about  indoor  air  quality  in the  Baltimore
       metropolitan area

     o Investigate possible  programs to reduce exposure to indoor
       air pollutants and to recommend implementation of potential
       programs  to reduce air pollution.

     The tasks  associated with these goals are:

     (1)  review studies concerning  indoor air pollution .to estab-
          lish the importance and extent of  the  problem  and its
          relevance  to the Baltimore study area;

                               IX-3

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     (2)  examine possible programs to reduce indoor air pollution;
          and

     (3)  recommend programs to reduce indoor air pollution where
          appropriate.

Issue #3: Underground Storage Tanks

     The TAG and  the  MC chose leaking underground  storage tanks
(USTs) as an issue  to be studied in Phase II because  USTs rated
high on a variety of  factors  associated with ground-water  conta-
mination and resource impact.

     Leaking underground storage  tanks pose  potentially signifi-
cant pollution  problems in  the  Baltimore  area.   Reducing  the
problem through development of requirements for underground tanks
and through  identification  of  tanks  most  likely to leak  has
proved to be a difficult undertaking. The characteristics of tank
failure are hard  to  predict;  the timing  and magnitude of tank
failure are highly variable even  for the  same type of  tank under
similar circumstances.  In  addition,  once  a leak  occurs,  the
damage from leaks will  vary even  for the  same type and volume of
release.  Local hydrogeologic  conditions,  the proximity to popu-
lation, the use of  ground-water,  and ecological factors all play
important roles.  Given limited resources, government authorities
face a  need  to set priorities regarding  inspection and enforce-
ment activities.  Those tanks  located in areas of greatest hydro-
geologic vulnerability  and where  groundwater wells are  densely
located, deserve high priority.

     The goals  of  the  workplan  for  underground  tanks  are  as
follows:

        0  Set  priorities for  inspection  and enforcement.   Which
          leaking tanks  are  most likely  to  pose the  greatest
          ground-water  resource damage?

        0  Provide a  tool which can  be readily  used by state and
          local officials  in the  study area  as well as elsewhere,
          to help in  setting  priorities  for  managing underground
          storage tanks.

     The workplan  identifies  the following tasks necessary to
achieve these goals:

     (1)  develop an information management tool which  can  operate
          on a personal computer,  and which displays and integrates
          information on  hydrogeologic  conditions,  population,
          ground-water  use, and  tank location.   The tool must be
          able to be used and updated on an on-going basis and
          allow mapping of factors of concern.
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      (2)  develop  tools  and  methods  to describe  the extent  to
          which leaking underground storage tanks can potentially
          result in  impacts  on groundwater  resources.   Implicit
          in considering impact on the resource is some considera-
          tion of health risk (based on number of people affected
          on a polluted well) and economic impacts (based on number
          of wells affected)  With  these instruments, the workgroup
          will prepare a matrix displaying areas  of greatest ground-
          water resource impact.

      (3)  develop a  "cookbook"  which would  enable other  states
          and localities to perform similar studies.

Issue #4: Multimedia Metals

     The MC and  the TAG chose  the issue of  "multimedia  metals"
for Phase II study because metals  from a wide variety of  sources
and in  all media  were  found  to pose  potentially  significant
health and environmental risks.

     The goals of the work plan are

     o Characterize the environmental and health  risks associated
       with selected metals in the study area,

     o Determine subsequently  which  subsets  of  the  issue  are  of
       greatest concern to human health  and  the  environment,  and

     o Initiate  analyses  on  the   cost-effectiveness  of  control
       strategies for issues  judged  to be  of greatest  concern.

     The tasks associated  with  these goals are  described  below:

     (1) coordinate with other workgroups on metals-related issues.

     (2) complete work  associated with  the  initial  scoping  of
         issues dealing  with  metals.    A part   of  this  would
         involve writing  up  the results of  the  priority-setting
         process for  metals,  including  a  description  of  the
         methodology.  The second  part  would entail  developing
         recommendations  for   metals-related  issues  for  further
         study (but  not as part of the  IEMP).

     (3) develop cost-effective techniques  for lead paint  removal
         and dust abatement.
                               IX-5

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This latter task, because it will constitute the primary focus of
the metals work  group in Phase II, demands  greater  elaboration.

     An extensive number of  studies dealing  with various aspects
of exposure to lead have been carried out  in Baltimore.   In par-
ticular, those conducted under the aegis  of the Maryland Depart-
ment of Health  and Mental Hygiene and  Johns Hopkins  University
indicate that current techniques  for  abating lead paint and dust
are not very effective,  pose unnecessary risks to workers and, in
some cases, actually increase the levels of lead dust in housing.

     The purpose  of the project  will be  to design  and test  a
technique for  cost-effectively  reducing  lead  dust  levels  in
households.  The  pilot  project   will be   carried out  by  Drs.
Chisholm and  Farfel of  Johns  Hopkins University.   The approach
consists of three phases:

     o  Planning Phase—identifying and reviewing abatement
        techniques.  The Kennedy  Institute, with the  assistance
        of the  Baltimore Building  Congress  and  Exchange,  will
        convene a  meeting  of  experts  to discuss the technical
        and economic feasibility of various abatement techniques.
        The advisory body will include local experts in contract-
        ing architecture, paint and building supplies, and envi-
        ronmental health.  Also represented will be organizations
        involved  in upgrading low-income housing, which may volun-
     o  Demonstration Phase—demonstrating lead  abatement techni-
        ques.  For  about six  to  ten homes,  depending  upon the
        cost per  house,  the contractor will take household  dust
        samples before  and  after abatement  to  assess  the effec-
        tiveness  of  each technique.   We  will  document the costs
        in both  capital  and  labor which are associated with  each
        technique.

     o  Evaluation—evaluating cost-effectiveness  of each abate-
        ment technique.  We  will  assess the costs of each abate-
        ment technique  against  the   reduction  in lead  in  dust
        which is  achieved  in each home.   These  costs will  also
        be evaluated  against the  costs  incurred by  the city'^s
        current practices for handling  homes with levels of  lead
        paint deemed harmful to children.

     The expected product  of this project  will be an assessment
of the  cost-effectiveness  of alternative  techniques for abating
lead paint  in  residential  homes  which  are  adaptable to the
Baltimore region.   The  project will  also produce trained  abate-
ment teams that  can efficiently and effectively conduct  abatement
efforts in area housing.
                                IX-6

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Issue 15: Baltimore Harbor

     The TAG and  the  MC chose Baltimore harbor  as an  issue  for
Phase II because  of  the importance that pollution  of  the  harbor
can have  on current  and  future  uses  of   this  vital  resource.

     The eco-system within Baltimore Harbor has been  affected by
urban and industrial discharges over the past century and a half.
Various corrective measures,  such as  effluent limits,  sediment
controls, and regulation  of  dredging  spoils,  are now  in  place.
Nevertheless, the extent to which  additional remedial efforts  are
in order awaits policy decisions  regarding the ecological  state
to which  the Harbor  is to  be restored.   These  plans for  the
Harbor are,   in turn,  dependent upon a  thorough understanding of
ecosystem dynamics and the  determinants of  ecological health.
For example, environmental managers must understand how environ-
mental variables  (such as pollutants and aquatic habitats)  inter-
act to produce a  potential ecological  state (e.g., the  ability
of fish to breed  or  rockfish  to survive) before  they  can  devise
effective control strategies  for the pollutant.

     The objectives of the work plan are to  define  goals  for  the
future use of the harbor and to identify additional research  and
institutional arrangements  that should  occur to help environment-
al decision-makers understand  how  to achieve this  goal.  The work
group will also explore  methods to assess  the effects  of  pollu-
tants on aquatic  life.

     The tasks identified  to  achieve   these objectives  are  as
follows:

     1)   prepare   a  statement  of  overall  goals  for the  Harbor
         which states  the work group's  consensus on the desirable
         uses of   the  harbor.   The  statement will  identify  the
         steps  necessary for   the  harbor to progress  from  its
         current  state to these goals.

     2)   prepare   a  compendium of  existing  studies  describing
         the ecological status  of the  harbor  and  the  potential
         human health  and ecological effects of current pollutant
         levels.   The   studies  will  relate  to the  work group's
         statement of  goals which  will be  conducted in task  #1.
         This compendium will  serve to  identify areas  for  future
         research. The work group intends to deliver  this  "s^tate
         of  the harbor" document  to the Chesapeake Bay program,
         which  is  planning an ongoing research project on Baltimore
         Harbor.

     3)   coordinate  environmental  agencies  in the identification
         of  management strategies for the Harbor.  Several environ-
         mental agencies  have  jurisdiction  within  the  Baltimore
                               IX-7

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                Harbor.  These agencies are currently developing or have
                developed  studies and improvement projects  to enhance the
                Harbor  ecosystem.

             4)  develop and apply a method (eco-scoring) to assess the eco-
                logical effects on aquatic life of ambient concentrations
                of  metals  and organic substances in the water column.  The
                results will be  compared  to the results of the indexing
                exercise.   The  reasons for  any  inconsistencies  in the
                results will be  explored.
        Trihalomethanes  in  Drinking Water

             The TAG,  however,  felt that no work  plan or work group was
        necessary  for  this  issue, as the issue is already well understood.
        The TAG, as a group, will  compare  the potential risks from  tri-
        halomethanes  in  drinking water  to other  potential human health
        risks that may  be  associated with  other  environmental issues
        under study during  Phase  II.

             Under the  requirement  of  the Safe  Drinking  Water  Act  to
        establish  National  Interim  Primary Drinking Water  Standards, the
        EPA set a  maximum  contaminant  level  (MCL)  of  100 ug/liter for
        total trihalomethanes (THMs)  in drinking  water.  Trihalomethanes
        are formed during chlorine  disinfection of surface  water  supplies
        used for  potable  drinking   water.   Chloroform  is  suspected  of
        being a human carcinogen.   Consequently, any level of  exposure
        is, on the basis of  EPA  cancer policy, assumed  to be  associated
        with some  level of  cancer  risk—even  those  that conform to the
        current trihalomethane  MCL.

             Levels of trihalomethanes in drinking water in the Baltimore
        area currently  meet  this  standard.    Nevertheless,  we  estimate
        that cancer risks in the Baltimore area'from  drinking  water  con-
        taining trihalomethanes to  be roughly  one in  ten thousand (based
        on current CAG estimates of carcinogenic  potency for  chloroform)
        or three  excess  cancer cases.   The  TAG  and  the  MC  decided  to
        include this  issue for study  in Phase II because  they felt  that
        a multimedia   project  like   the Baltimore IEMP  should  consider
        these "regulated"  risks  for   comparison  with  other potential
        chronic human health  risks that  may  be  identified in Phase II.
                                       IX-8
«	 "	l"nl 	IIP " IIIIIIIIIIHH	V '111	'  W VVIIMV^MHMMmMMIW!•••!•

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 CHAPTER X




CONCLUSIONS

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                          X.  CONCLUSIONS
     The Baltimore IEMP contains three unusual  features.   First,
the framework in which decisions are made is different from other
lEMPs, let alone other EPA projects.   In  Baltimore,  EPA delegat-
ed management authority  to  the local level.  Second,  the  Balti-
more IEMP  included  examination  of  issues  of  ecological  and
resource impact,  in  addition  to health  related  issues.   Third,
the scope of  environmental  problems considered in Baltimore  was
wider than  previous   IEMP  projects.   We  highlight  four  major
accomplishments of Phase I.

We have established the organizational framework at the State  and
local levels for setting priorities for government action on envi-
ronmental issues.The ManagementCommitte(MC)withtheassis-
tance of the Technical Advisory Committee (TAG)  Affectively iden-
tified and set priorities among a wide-ranging and diverse set of
environmental issues  of  concern to public  officials.   The Phase
II topics, which  we  described in Chapter IX, are  the product of
this process.

The Baltimore IEMP has helped State and local governments develop
a working  understanding of  EPA  methods for analyzing issues.
Priority-setting in the  Baltimore  IEMP  was a  hands-on process.
The TAG played  an active role through  its provision  of  expert
judgment while  it used  analytical  tools  to identify important
environmental issues  and  compare  and rank them  against evalua-
tive criteria.  The success  of representatives of State and local
political jurisdictions  in  reaching  consensus  on questions  of
environmental priorities that  unevenly affect  them  testifies to
the usefulness of  these  tools and  these  governments'  ability to
use them.  In  addition,  EPA held  workshops for  both government
officials in Maryland and the public to familiarize them with  the
use of risk assessment.

The Baltimore IEMP has already helped State and local governments
identify  and address a  high-priority problem.   In  Phase   I  the
State and counties became aware of a potential health problem  re-
sulting from the high  levels  of lead used  in solder  .and flux in
residential plumbing.   They  have  already  effected   a  lowering
(from 2%  to  0.2%)  of  the standard for the  use of lead  in such
plumbing.  This is direct evidence  of a  positive effect on envi-
ronmental management  in Baltimore.  However, most of the tangible
progress towards solving environmental problems is generally  not
e'xpected until  completion  of  the  second phase of  the project.

The Baltimore  IEMP has provided  information  that will help  EPA
conduct its programs.  EPA has lacked analytical methods and pro-
cedures for setting priorities among issues that do not directly
relate to health.  In Phase  I of the Baltimore  IEMP, we made pro-
gress in developing  priority-setting tools for ecological issues


                               X-l

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relating  to  the  aquatic  environment  and   in  a  procedure  for
achieving  consensus  on  issues  of  importance  to  ground-water
resources.

CONCLUSIONS REGARDING THE INSTITUTIONAL ARRANGEMENTS

      A key  factor in the  success  of  the  process in Phase  I is
EPA's delegation  of  management  authority  to  State  and  local
governments.  This  sense  of "local  ownership"  has  resulted in a
greater commitment  and more  active  involvement  from  State  and
local officals than is typical for EPA-run projects.

      The provision  of  a forum  for  discussion among governmental
agencies  is  also  important. Indeed,  we  hope this organizational
framework will  prove  to be an  enduring legacy of  this  phase of
the project.  Its  enduring nature is already attested to  by  the
continued enthusiastic involvement of project members after nearly
three years, the well-attended meetings of the TAG and workgroups,
and the  active  role that members  have played  in  developing  and
overseeing the execution of work plans.

      The  IEMP also  provided a  common  language  for communicating
about and  understanding  certain environmental problems.   Risk
assessment, for  example,  became  the  "common  denominator"  for
discussion of a  wide  variety  of health  issues  that concern many
agencies.  It served to open  channels of communication on diffe-
rent  topics  of  common interest.  Thus the  structure  of the IEMP
extended the lines of communication  outside  immediate profession-
al concerns and allowed for cross-fertilization of ideas.

      Finally the  institutional  structure  of the IEMP provided an
excellent forum for examining issues not clearly the responsibil-
ity of any  one  agency of-government.   Indoor air,  especially of
residences, is a  case  in  point.   By bringing together interested
government and private parties,  all  facets  of the issue could be
objectively examined and diverse expertise from a wide variety of
disciplines brought to bear on the issue.

ANALYTIC FINDINGS

Human Health Risks

     We have estimated  several  types of health  risks.   For expo-
sures that could increase the  risk of cancer,  we made conservative
estimates of: (1)  possible incidence, or the number of excess cases
(beyond baseline occurrences)  of the  disease  that may develop; (2)
average exposed individual  (AEI) risk, or the probability that a
typical individual may  develop  the  disease  over  a lifetime;  (3)
maximum exposed individual  (MEI) risk, or the probability that a
typical individual exposed  to the  highest predicted ambient con-
centration of pollutants may develop the disease over a lifetime.
For health  effects  other  than cancer,  we compared  estimated


                               X-2

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exposure levels with  an estimated  reference  dose, or  no-effect
threshold, below which exposure is judged to be safe.

     It is important to bear  in  mind  the limitations  and caveats
to this  analysis  (discussed  in   greater  detail  in  Chapter  V).
Among the most important are the following:

     0 The Phase I analyses are based on limited data.

     0 The principal  purposes of the  Phase  I  analyses are  to
       give a sense  of  the severity of a problem  and  to compare
       problems for  setting  priorities  for  further  study  in
       Phase II.  They  do  not make  definitive statements  about
       actual disease incidence in the local population.

     0 Generally speaking,  the  assumptions  used  in  the analyses
       are conservative  and  tend to   overestimate  risks;  (the
       numbers presented are  upper-bound  estimates).   However to
       the extent the analyses  suffer  from omissions  and uncer-
       tainties, risks may be underestimated.

     0 Finally, the  results  are  not  the product  of  a  comprehen-
       sive appraisal of all environmental risks in the Baltimore
       study area.

     Exposure                                   •

     Of the ten organic  compounds evaluated  in the  ambient air,
the highest  measured concentrations  were  for  benzene,  xylene,
toluene, and ethyl benzene.   For the metals  studied,  only  chro-
mium appears  to  be  in  somewhat  elevated  concentrations in  the
ambient air  of  Baltimore.   Results  from the Baltimore IEMP  and
Maryland air toxics  monitoring program  indicated  that  there  can
be significant variation in  the  concentrations of  some organics
and metals in  the Baltimore  area.   This is  an  important factor
to consider during Phase II when we will explore control options.

     Based upon monitoring data  from  other  cities,  indoor  air
pollutant levels in homes in Baltimore could be higher  than ambi-.
ent air concentrations for the subset  of pollutants  evaluated in
the Baltimore IEMP.   In some instances, indoor air concentrations
may be ten times higher.

     The only  class  of  volatile  organic  compounds  in drinking
water to  which  people  are  significantly  exposed  is   trihalome-
thanes, which result from  disinfection of drinking water through
chlorination.

     Lead can also be  present in  elevated  concentrations in tao
water and dust from  historical use of  lead paint.   Studies con-
ducted in other  cities suggest  that  corrosive water  can  cause
                               X-3
                              II" "IMP W'"111PI»MI

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        lead to  leach  out of  residential  plumbing  that  contains  lead
        solder or  flux, leading to high  concentrations  in  the  first few
        minutes of  flow.   Young children  in older homes that  have  been
        previously  painted  with lead based  paint are often  exposed and
        ingest the  dust containing  lead.   The result is a  dramatic increase
        in blood lead levels.

        Cancer Risks

             Of the ten organic compounds monitored in the ambient air in
        Baltimore,  we found  that  benzene clearly posed the  greatest risk
        (an upper-bound estimate  of  roughly 3  excess  cancer  cases per
        year).  The next three  important organic  compounds with regard to
        cancer risk were perchloroethylene,  chloroform,  and carbon tetra-
        chloride; together  these  three  posed upper-bound  risk  of  less
        than one excess cancer  case.

             Of the metals examined  in the  ambient  air, we  found  only
        chromium to be at levels that could be of  concern  to human health.
        Under the worst case assumption  (that all  the  chromium is hexava-
        lent and thus carcinogenic), the  risk (an  upper-bound estimate of
        roughly 4  excess  cancer cases per year)  is roughly comparable to
        that posed  by the  organic compounds  studied.

             In total,  our analysis suggests an upper-bound  estimate of
        roughly 7 excess cancer cases per year from the  organic compounds
        and metals  examined in  the  ambient air.

             Even though  trihalomethanes and  other  pollutants  that the
        IEMP was  able  to  identify  in the public  drinking  water  were at
        levels well below  federal  drinking water  standards, these pollu-
        tants may  pose  some cancer risk.  This  is  because the lifetime
        risk —  roughly 1  in  10,000 —  is  shared by nearly  the entire
        population  of the  study area.   The upper-bound estimate of  3 ex-
        cess cancer cases  per  year is  roughly  equivalent  to  that  posed
        by the  set  of  organic  compounds  that we examined in the ambient
        air.  The  risk  from trihalomethanes in  drinking water  would be
        half that posed by the  total  ambient air  riskr when metals in the
        air are included  and  the  chromium is assumed .to  be hexavalent —
        an upper-bound  estimate of  3 versus  7 annual  excess cancer cases.

             As previously  mentioned in  both the Executive  Summary and
        Chapter V,  these  numbers  should be  compared with  the estimated
        baseline incidence of cancer cases  in the study  area - 8227  oases
        per year.   [In  1983,  the  American Cancer  Society estimated  there
        were 1.92  cases of cancer  nationally for each  cancer death.   In
        1984 cancer mortality in the Baltimore study  area was 4285.  Mul-
        tiplying these  factors  produces the estimate  of the  baseline of
        8227 annual cases] .

             Preliminary risk calculations  for  indoor air using  national
        data suggest that  indoor air pollution may be a  relatively signi-
        ficant potential source of  risk  in  the Baltimore study area. The


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estimated risks were  higher  than  those  calculated  for  ambient
exposures in the other cities studied-.

Noncancer Risks

     The preliminary Phase  I findings  suggest  that  most of  the
Baltimore population will be exposed to  chemicals at  concentra-
tions high enough to cause  concern  over  noncancer  effects.   Ben-
zene concentrations in  the  ambient  air  may increase the  risk  of
fetal developmental effects  for  the unborn children of pregnant
women in the  study  area.  Ambient  air  concentrations  of  chloro-
form could  also pose  an elevated  risk  of fetal  developmental
effects.  Data  from  other  cities on indoor concentrations of  a
number of  toxic substances,  including  benzene, chloroform,  and
carbon tetrachloride,  indicate that, also in the Baltimore  area,
there may be some cause for  concern over noncancer  health effects
from exposure to these  substances.   We cannot  ascertain  the  ex-
tent or the kinds of risks without further study.

     Lead in the first few minutes of flow  of tap  water can con-
tribute to the  Baltimore area  residents"  overall  intake of  lead;
it may put the unborn child  and young children at  greater risk of
adverse neurological effects  and adult  males  at greater  risk  of
hypertension.   Ingestion of  lead  in household dust is clearly a
very significant threat to  the health of  young  children in  older
homes which have been painted with lead-based paint.

Potential Threats to Ground-Water Resources

     The evaluation of potential sources  of pollution  of  ground-
water resources indicated that the most  significant are: a source,
underground storage tanks;  and  a  class  of pollutants,  metals.
Note that the  analysis  does not conclude they  are problems;  the
Phase I analysis  focused on  ranking the relative importance  of
potential sources.

     Underground storage tanks rated high on all factors  of con-
cern.  Of particular concern were the large number of  sources and
their location  above aquifers that are existing or future sources
of drinking water in Baltimore and Anne Arundel Counties.

     Possible threats from  metals include:  chromium  deposited as
fill in the harbor area; metals which leach from surface  impound-
ments and  landfills  into ground  water;  and  municipal landfills
when located  in areas that  are now  or  could be used for drinking
water.

Ecological Impact on the Harbor

       The indexing exercise we conducted (using existing data
bases and  results  from a limited monitoring program)  lead  us to
conclude that mercury may be of more acute  concern than the other
metals studied.  Zinc,  chromium,  copper,  and  lead may also pose
problems for the Harbor.


                               X-5

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                APPENDIX  A








            GENERAL METHODOLOGY




                   FOR AN




INTEGRATED ENVIRONMENTAL MANAGEMENT PROJECT

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               APPENDIX A.  GENERAL METHODOLOGY
     This Appendix provides a general overview of  the  analytical
steps which EPA employs in Phase I  of an Integrated Environmental
Management Project  (IEMP)  in  the assessment of  risks.  It  also
defines the concepts  of  risk assessment and risk  management and
describes the  analytical  methods used  for  risk  assessment.   By
and large,  the Baltimore  IEMP  followed these steps,  with  some
variations.
APPLICATION OF METHODOLOGY

     This section presents  a  comprehensive description of  EPA's
general methodology  for  conducting an  IEMP.   When  we  actually
apply this approach,  inevitable practical  limitations (such  as
time and resource  constraints,  or limits  on  the state of  know-
ledge) and the  characteristics  of  the  particular site force  us
to tailor our efforts to our conditions.  As a result,  we do  not
necessarily apply and develop the full framework  and  its analyti-
cal tools in  any one IEMP.   Moreover,  we  also  believe that  we
can achieve the most progress if we are flexible in  applying  the
approach and  if we  adapt  to  new  circumstances as  information
becomes available during the course of  the analysis.  Therefore,
the framework should  not  be considered to  be a  rigid  blueprint;
its specific  application  can  vary from  one  study  to another,
although the general approach will remain unchanged.

     There are  significant  limitations  and uncertainties  associ-
ated with the lEMP's methodology,  which warrant  consideration  be-
fore examining  the actual procedures.   First, the risk estimates
are based primarily on existing knowledge about pollutant potency,
releases, and ambient conditions;  these data,  however,  vary wide-
ly in quality and  are almost  always incomplete.   Second,  the  ex-
posure estimates incorporate a series of simplifying  assumptions;
although these  assumptions  are  necessary,  they  they remain open
to question and may be controversial.  Third, the potency  esti-
mates are necessarily based on current knowledge  of the toxicolo-
gical effects  of various  substances.  Considerable controversy
exists about the degree of  hazard  posed by different pollutants,
and about whether  some  are hazardous at  all.  Finally, resource
and time constraints and the breadth of our focus prevent us from
analyzing individual issues in as much depth as might be possible.
We have  attempted  to strike  a  balance  between the  desire  for
exhaustive and definitive analysis and  the  need  for  results at a
reasonable cost.

     As noted  at  the beginning  of this  Appendix,  the range  of
potential environmental issues  at  any  site is  so large  that  it
                               A-l

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would be impossible, given  limited  resources, to  conduct the  in-
depth analysis that  would be required to  study all of  the more
complex problems.   Therefore,  to  manage  an  integrated  study
effectively it is  necessary  to  focus on  a  small  set  of  study
topics.  Although the screening process is designated as a single
step in  Phase  I,   screening actually  takes  place  continually
throughout the  project  as   new  information  becomes  available.

     In its simplest form an IEMP consists of  seven  steps  orga-
nized into two phases.   An outline of the steps  is provided below
and is followed by a more detailed discussion.

     Phase I
     1.   Establishing  arrangements between institutions cooper-
          ating on the  project

     2.   Defining the  scope of the project:

          --Setting geographic boundaries

          —Making an initial selection of  pollutants  and issues
            for study

          —Establishing risk assessment approaches, e.g., selec-
           .ting the health effects of concern

     3.   Collecting information on sources, pollutants, and
          exposure pathways   for  entry into a computerized  data-
          base

     4.   Performing a  screening analysis on the initial selec-
          tion of  pollutants  and  sources  to   determine  which
          of those should receive  further  attention in Phase  II.
          The screen involves two complementary  approaches:

          —Evaluating  risks to determine which  pollutants,
            sources, and  exposure  pathways are most  significant

          —Qualitatively assessing analytical feasibility;  rele-
            vance to EPA,  state, and local  program  objectives;
            and potential for effective response

     Phase II
     5.   Gathering additional data to confirm and refine the
          risk assessments performed  in Phase  I,  and  to  adjust
          priorities accordingly

     6.   Analyzing and evaluating the cost-effectiveness of
          alternative control options

     7.  Developing conclusions


                                A-2

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These steps  and  related  issues  are discussed  in the  following
sections.

Phase It  Initial Issue Selection and Screening

     Establishing Institutional Arrangements

     The first step  is to  set up cooperative^ working  relation-
ships with all responsible  state, local, and  federal  groups  with
direct responsibility for public health protection.   Working re-
lationships with industry,  environmental groups,  and  other inte-
rested parties are also highly advisable.

     Defining the Scope of the Project (Scoping)

     One of the  first  tasks is to reach an agreement with these
groups on  such  basic matters  as the  general scopei  focus,  and
objectives of the  effort,  the responsibilities  of  the  various
parties, and the study's geographic boundaries.  The key activity
of this task  is  to  identify and select chemicals  and issues for
consideration in Phase I.  Decisions must be  made as  to which of
the many  thousands  of potential  environmental  contaminants  are
likely to be present in the media of  concern,  and which of these
warrant the  expenditure  of time and  resources  to  detect.   This
is because  our   ambient  monitoring  equipment cannot adequately
identify all  substances present;  indeed*  it  is  generally neces-
sary to specifically look for  a pollutant  in  order to detect it.

     There are many  approaches  for  arriving  at a list  of  sub-
stances which should be  looked for,  but  they all  face the  same
constraints:  the amount  of resources available and  the availa-
bility and  sophistication  of detection equipment.  The approach
used should  ideally  allow  a   fair  comparison of issues  yet be
flexible enough  to  accommodate specific  geographic constraints.

     All the decisions involved  in scoping are   not  necessarily
made at  one point in time.   In the process  of  the  risk screen
(which we describe below),  new issues  or  pollutants can be iden-
tified.  The  scope  of  the project  can  then  be redefined to
include these  new  issues   which  are  deemed   to be  • significant
enough for inclusion in the project.

     One of the  more  important actions made  during this process
is the placing of  issues which  we  have identified  into broader
relational or reference  categories.'   Examples of  such  reference
categories, which  we  used   in the  Baltimore  IEMP,  are public
health .impact,  ecological  impact,   and  threats  to  groundwater
resources.  By grouping issues into  reference categories, we are
more likely to find  a  "common denominator"  or unifying principle
to be used  in evaluating  the overall  level of risk  attributable
to each  issue—within  that particular reference category.  This
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allows like comparisons rather than having to confront the dilem-
ma of comparing different subjects  for  which there  is  no  obvious
common denominator.  This aspect of  scoping  as  it applies to the
Baltimore IEMP is discussed in more  detail in Chapter IV.   [Some
issues can be placed into more than one reference category; toxic
contamination of fish,  for example, can not only be an ecological
problem, but at the same time a public health threat.]

     After issues  have  been  grouped   in  reference  categories,
project participants may decide to  consider  only one,  or perhaps
just a subset, of these groupings of issues.  Such was the case in
both Santa Clara  and Philadelphia.   At the  outset  of these pro-
ject participants decided to  study  only issues  relating to human
health risks.

     Developing a Database

     The next step is to design a database that is appropriate to
the scope and objectives of the study.   One approach is to gather
and inspect  all  readily available  information  on  the  issues
selected, i.e.,  sources,  environmental  releases,   and  exposed
populations for each medium.   State, county, and city agencies,
permit writers, EPA, and local industrial facilities are the pri-
mary sources of these data, which  should  be  collected and evalu-
ated before new data is generated.
                                                ^

     After the  available data  have been reviewed,  engineering
estimates, in many  cases,  can be used  to fill  the  gaps and pro-
vide the  needed  information  to  compare  issues.   In  almost  all
cases, engineering estimates  are  needed to  calculate intermedia
transfers.  (Intermedia  transfers  are  the  relocation  of  pollu-
tants from one medium to another.   For  example, the incineration
of waste  reduces  --  but does  not  eliminate —  the  volume  of
solid material requiring  landfilling.   However, .the  process  may
also produce air-borne pollutants.)  For  certain common sources,
such as dry cleaners, degreasers, mobile  sources (air),  and non-
point run-off  (water),  EPA's  Regulatory Integration  Division in
the Office of  Policy Analysis has developed  algorithms to esti-
mate pollutant loadings  to all  relevant media that  are  easily
adapted to different geographic areas.  In some situations,  some
new monitoring may  be  initiated  at this  stage if it  is  deemed
necessary for setting priorities.

     The Screening Process

     The screening process  selects  and sets priorities  for  the
issues to be  studied  in Phase II.   The process  is emphatically
not one that  can  be performed in  a  mechanical  way,  but  instead
relies on continuous evaluation of data,  especially when  compar-
ing potential risks.
                                A-4

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     The screening  process  involves  two  complementary  steps.
The first step quantifies  risks  to human health or  the  environ-
ment to identify  the  sources,  pollutants, and  exposure  pathways
of greatest concern.  This "risk  screen"  represents a preliminary
attempt at  quantitative  assessment,  using  available  data,  and
therefore may not  generate results sufficiently complete  to  use
in setting priorities.

     For that reason,  we also use a second  step which  focuses on
issues that are  not readily quantified.   This  approach  qualita-
tively assesses an  issue's  analytical  feasibility;  its relevance
to EPA, state,  and local  program  objectives;  and  its potential
for effective response (i.e., controllability).

     Step 1;  Risk Screen.   The  risk  screen  is  a  preliminary
quantitative assessment of the risks to human health or the envi-
ronment, performed  to  identify  the  sources,   pollutants,  and
exposure pathways  of  greatest concern.   This  assessment  can be
made in a  variety of ways,  depending  on the topic  of interest.
For example, we  can examine either  the  variety of  sources that
contribute to pollution  in  one  medium,   or we  can address-  the
sources of pollution in several media, each  of  which contributes
to the same health effect.

     It may take several cuts at the entire  set of issues  within
a reference category to develop the best  common denominator. Once
this common denominator  is  developed,  a subset of issues will
become particularly significant.   For  example,  if  the  study par-
ticipants determine  that  carcinogenic  effects  should  be  the
"common currency" of evaluation, those issues  or conditions that
might be expected  to  cause greater levels  of  cancer will  become
more important than those  that might cause  other types of health
consequences.

     Because the  focus of  the IEMP  analysis is for policy pur-
poses and due to  inevitable resource  constraints,  the IEMP pro-
ject manager must  reserve the bulk of  the  study  resources  for
the later steps.   For that reason, the  risk estimates generated
for the screen  are not precise  estimates but  rather  very rough
approximations that are  just  suitable  for setting priorities.
In fact, the  information  available to drive the  risk screen is
not likely to be  adequate  even to identify  the  relative ranking
of issues with much certainty;  instead,   it  serves only to group
the issues into three broad categories:  (1) those that are  likely
to pose high  risk, (2) those  with the  potential  for high risk
but little  substantive  evidence, and  (3) those that  are   likely
to pose relatively  low  risk.  Discretion must  be  used in  deter-
mining when enough data have been  gathered  to  support  a success-
ful risk screen.
                               A-5
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     Step 2:  Qualitative Evaluation.  After  the  issues  identi-
 fied in Phase I as potential candidates for Phase II analyses are
 separated into the three groups based on quantitative measures of
 risk, the issues  classified  in the first two groups (high risks)
 are further evaluated using nonrisk or secondary criteria.  These
 secondary criteria,  applied  to the first two groups of high risk
 issues, provide broader perspectives  for setting priorities than
 those based solely on risk assessment criteria.  As more informa-
 tion becomes  available,  further  reclassification  of  the issues
 may be  warranted.  The secondary criteria are  discussed below.
 Like the  rest of the  priority-setting  process,  they  should not
 be regarded as  being inflexible.   Other  groups  conducting inte-
 grated studies may want to modify or add to these  criteria.  For
 example, the Baltimore IEMP added  an explicit criterion of avoid-
 ing duplication of existing analyses of control programs.

     Analytical Feasibility

     The primary  elements determining analytical feasibility are
 the amount  of  supporting data available,  the  availability  of
 analytical methods,  and the  level of  effort required to generate
 new data.  These  are basically program  management considerations
 in that they  indicate  how much effort would  be  needed for basic
 data gathering before developing  management  alternatives  (e.g.,
 for control).  There is  an  important  tradeoff  implicit  in the
 criterion of  analytical  feasibility:    the  greatest  payoff  in
 terms of  identifying and  controlling toxics  may be  in studying
 issues that have not been studied  in the past or have been avoid-
 ed because of the complexity or magnitude  of the  issue.   On the
 other hand,  within the time and budget available for the project,
 it may not  be feasible to characterize  these issues adequately,
 and it may be necessary to curtail the analysis short of develop-
 ing complete risk management strategies.

     Relevance to EPA, State, and  Local Program Objectives

  f   The elements of this  criterion involve  the significance of
 the issue for national EPA programs  and state and local interest
 in the issue.  One of our objectives is to use the IEMP projects
 to indicate where shifts in EPA priorities and methods are appro-
 priate,  so the relationship of the issue to national EPA programs
 is an important  factor.   State and  local interest  affects the
 extent of support that local  and  state  participants will give to
 the detailed study effort,  and also strongly affects  the feasi-
bility of implementing control strategies, when warranted.

     Potential for Effective Response

     The level of existing   control  provides a  rough  measure of
 the likelihood that additional controls are cost-effective, since
 cost-effectiveness generally  declines  with  increasing  control.
                               A-6

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The feasibility rpf' additional controls -is  also important^ if  no
technological, institutional,: and political  means  are. available
to reduce risk, the  issue ,is probably^ not ,a useful candsida,te  for
study:  ;~    _    ;,    \ '  -\  ",„.   ,.....,^    '.,..,     v

     Risk Management Challenges in?'Interpreting Results and
Applying the Process.   '         T

     In the  process  of  establishing priorities,  study partici-
pants are likely  to encounter  several' basic problems involving
the interpretation and application of environmental risk informa-
tion.  Some, specific issues are discussed below.     ;

     Maximum Exposed  Individual  Risks  Versus  Total Population
     Risks                                  ¥

     The management  or project   advisory  group  selecting  study
topics will have  to confront one of  the  classic  trade offs  in
risk management--that of maximum exposed individual  versus  cumu-
lative population  risks.    Inevitably*  some  of   the potential
study topics  will involve  situations  where  a relatively  small
number of people  experience risks higher than^those  faced by the
aggregate population;  these  topics  do not necessarily coincide
with those where  there  are  widespread risks.   Decisions may have
to be"made whether"to  spend study resources  to help  a few people
by a substantial margin or  to spend  them toJhelp many people by a.
modest margin.  This issue  is one of the most difficult  issues in
setting priorities.

     Comparing .Across Effects         "•

     Anotherxdiff icult  issue  involves the*  comparison  of  risks
across different health  effects   (e.g., kidney damage ,versus can-
cer).  Typically, this is /done on ting basis of j^nformed  judgment.
RID is developing an approach €b  seating priorities that attempts
to accounti;¥for the  severity of  different effects.   There  have
been several  other  attempts' to  scale different  health  effects
(for instance, EPA\s  Off ice,; of  Solid  Waste has developed such a
scale), but this  issue  may  be most  effectively resolved by con-
sidering local  concern for the  severity ^p^f *dif ferent effects.
     •.. .  ' P-      y  v-    '* '  ...      •'' ""''"'  "   '' ''"  •*•-""   ~" ':    '•''..
     Comparing Human  Health Effects  :jtq  EnvjLrpnmental : Effects
        M          •..      ""'-'.        •   '     '•}£''.'  •'-;
     In cases  where  the scope of;i the  study,  as in theCBaltimore
IEMP, includes human health as well as ecological  issues, diffi-
cult value  judgments  must   be  made. ^ These  judgmerits  are  not
generally/made within  the  same  policy decision analysis  because
the quantitative  means -*gf!  equating, -thev two^ veiry _4if:f eient.., public,.
policy objectives a^e 'lackying. It5 is (ile^arly  important/ita protect
both public  health  and pur ecosystems,* bu/|r tKe value.,,placed oh
                                A-7

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human health* is not the same as that placed on our other environ-
mental ^goals'.   Decisions  cpncerning  the  s'etting of  priorities
between "these  two  types  of  issues   (because  the  quantitative
measures used to assess adverse impacts for each are not scienti-
fically or  analytically  comparable)  involve  the difficult and
necessarily subjective  Balancing  of  both  public policy  objec-
tiyes.

     Phase I Product     ;

     This Report contains  information  about theHrisks we quanti-
fied, identifies priority  issues  based on  our  risk assessments,
and describes the  methods we used to  assess  exposure and risks.
Furthermore, it  describes the  process by  which  these  products
were made possible.  in this. regard, we elaborate on the institu-
tional arrangements necessary  for  the  making of key policy  deci-
sions and  management  judgements  and  the  manner  in  which  these
decisions were made.

Phase II;  Risk Management Control Options
     After Xfeers elect ing Phase I issues warranting further analy-
sis, we begin Phase  II.  Phase  II  consists of three major tasks:
additional data  gathering  to  improve  our  exposure  and , risk
assessments, a  scientific  review  of  our  risk  assessments,  and
analysis of control options.

     Additional Data Gathering
                           • *
     By definition,  in. Phase  I  we identify the  study 'topics for
further analysis  using ~ existing  and  special engineering  esti-
mates.  While  this  is  reasonable  for  setting  priorities^ the
quality of  the  data  becomes  .even  more important at  the  later
stages of the  study.   Depending on the  specific issue, in Phase
II we  generally engage in further data  gathering in  'order to:.
(1) confirm whether  an  issue  warrants further investment of time
and resources,  (2)  ensure  that data  used  in later steps  are as
accurate ^as possible*  and  (.3)  revise Phase I  priorities  where
appropriate.   '      ^' .
     •• *        •&:•'.'•'•'    - ... •         •  >     "       ".,,.•'
         *     "•    ' \, '•(••••••         :•         -      •«.
     In some cases,  the  objective of  additional data  collection
may be to improve^ our understanding of the significance of parti-
cular pollutants and  sources.   This situation may only "call for
limited monitoring.
          - '* '"            *3
     In other cases,  which are really at the core  of the Phase II
activities," the objective  will be to  analyze the costs of poten-
tial control alternatives,  where effectiveness is measured by the
reduction in health  risk^-eith'er Most Expo sect  Individual   (MEl)
(defined ori'p.^'A.1'5)  risk or 'total population  incidence.  In these
                               A-8

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situations, we will need  to  ensure  that  our estimates of pollu-
tant loadings and  ambient concentrations,  for example, are  rea-
sonable and  representative  of avera'ge annual  conditions.  These
efforts may  include consulting  local environmental agencies  and
plant managers to  confirm underlying data  on ambient releases,
as well as initiating  an extensive monitoring program.

     As additional information  is gathered  in Phase  II,  it  is
helpful to periodically re-evaluate  the Phase  II  issues  in  terms
of potential risk.  This can often be done  by conducting  a sensi-
tivity analysis using the revised data.  New information  may in-
dicate that  the  risks  are  not  likely  to be  as  great  as   once
thought, or  they  may  be  greater than  originally  anticipated.
Sensitivity analyses of new  information provide a  way  to  further
focus the use of project resources during Phase II.

     Developing Pollution Control Options

     The next step  in  Phase  II is to assess alternative  control
strategies for the subset of  environmental  issues  identified for
this work.   A  very significant objective is to provide  analysis
of how to  reduce  risks  to health  (total population as  well  as to
the maximum  exposed individual)  or the environment  (the  measure
of effectiveness)  at the  minimum cost.  This  occurs through the
lEMP's cost-effectiveness analysis,  which presents, the tradeoffs
of costs and risk reductions  that  decision makers usually take
into consideration when formulating regulatory strategies.   The
analysis considers risks  that, .result from  exposure to  primary as
well as  secondary (intermedia)  releases.    It  is our  intention
that community  decision-makers  use  it  to   shape  their  general
strategies for providing  additional environmental  protection in
the area.

     There are three major  components to an analysis  of  control
options:  quantitative measures of ambient  concentrations at the
point of exposure; estimates  of  exposure and risk; and the  costs
and efficiencies of feasible  control options.  Data collected in
Phase I and supplemented in Phase II provide the necessary infor-
mation on pollutant loadings  estimates.  We  generally  employ EPA
fate and .transport  models to develop  ambient concentrations at
the point  of  exposure.   Exposure and risk  calculations  are then
made using  standard  EPA  assumptions,   which  we  discuss  later
in this chapter.

     We identify  feasible  control  options  and   estimate  their
associated  costs  and   efficiencies by  employing  engineering
assessments and  EPA  technical   documents  developed  to  support
various regulatory activities.

     The application of this process  will inevitably vary  from
one project  to  the next.   In  Philadelphia,  we  implemented the
                               A-9

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basics of  this  methodology.  However,  because Philadelphia  was
our first  project,  we did  not have  experience to  guide us  in
assembling the steps  in an  efficient  manner.   Largely  because of
lack of  sophistication with  the  methodology,  we  chose  not  to
examine other  issues  which would  involve ecological and  non-
cancer health effects.

     In the  Baltimore IEMP, we have  expanded  the  scope of  the
project to include ecological impacts  and have decided  to examine
non-cancer health effects in Phase II.  We will again be treading
new ground in developing  analytic methodologies to  examine  eco-
logical impacts and the risk of non-cancer effects.
RISK ASSESSMENT AND RISK MANAGEMENT

     The two key organizing concepts of an integrated environmen-
tal management project are  risk assessment and  risk management.
Risk assessment is the central  task of Phase I;  risk management
is the central  task  of Phase II.   Conceptually,  risk assessment
should be done independently of risk management.!   In IEMP
studies,  we  separate   assessment  from management  as  much  as
possible; however, this  is  not always  possible  so that  some  of
the activities in Phase I and Phase II overlap.

     We emphasize that our discussion of the  IEMP methodology  is
presented at a  conceptual level;  bur  actual  application  of  the
methodology may vary  from one  geographic project  to the  next.
Furthermore, we may  use  different  methods  in  response  to  the
needs of a  particular IEMP.   For  example, project  participants
in the Baltimore  IEMP had identified issues pertaining  to local
ecology and groundwater resources,  in addition  to health issues,
for study in Phase I.  To assess the significance of these issues
and to decide  which  of   them  warranted  further examination  in
Phase II, we needed different analytical tools from those we used
in setting priorities  among  human health  issues  in Philadelphia
and the  Santa  Clara Valley.   (Note that Philadelphia and Santa
Clara Valley  are  areas  where  we  conducted  earlier  geographic
studies.)  We describe these other-  (nonhealth  related) methods  in
Chapters VI (Analysis of  sources with Potential Adverse Impacts on
Ground-water) and VII (Analysis of Ecological  Impact) and discuss
only our methods  for  analyzing  risks  to human health  in  this
Appendix.

Phase I Risk Assessment and Priority-Setting

    There  are  always  more  environmental  issues  to study  than
resources with which  to  address them in a manner  that  will lead
to their  successful resolution.   A key task of Phase I of an IEMP
is, therefore,  this: to choose  which issues demand the  immediate
                               A-10

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     *.    i           •      -:      r     •.    •*' .         •      ;-
attention of  environmental^.--- official's-?rarid- the  expenditure   of
their time and  resources--and  which can- : be addressed at a later
date.  Suchrf comparingf of  issues 'and  s'e.tting of  priorities  re-
quires thatvvall issues  be reduced  to -a 'common  element.    (Note
that an integrated approach "to all iss,ues,;-means ^we try to examine
the same issue  across media.   An IEMPlo.s not ,,a comprehensive look
at all the environmental issues of the study^p^ea.)   Riski either
to human health or the^environment  (pr ^othfe^iis the common ele-
ment we  use  for  comparing  environmental^ issues in geographic
studies. ffcRisk  can be Categorized in several different ways.   As
appropriate, "we can  examine .risk ass,pcia*tedi;w,ith exposurjgs^ from
a specific  pollutant source.   We  can examine  risks associated
with exposure  to pollutants,   irrespective of  source.  •  We  can
look at risk  associated  with  exposures in  a  s;ingle  environmental
medium, such as air, water, or  food.  We can examine r^isks  asso-
ciated with  exposure ^'pathways.   In  the  absence"  of   other impor-
tant considerations,"":- the  mbre   significant  the  risk,  the more
likely the  issue  will rank high iir priority for examination  in
Phase II,  the  risk  management  phase.   Important considerations
that may   alter  the  priority  ranking   include,  for  example,
resource limitations  or  the  fact   that  a particular ^IBsue  is
already being handled by the  Federal,  state of local government.
              " '        '    •         :         '       -fti'f.      '•*•
              ;'-.     i- „.,.,.  '        ,'.v- ^  •,            V^.
     The  risks we  examine are  associated  with exposure to  toxic
chemicals in the environment and represent  estimates  of the poten-
tial for these  exposures to cause adverse effects.   Chemical's  can
adversely affect human health,  ands>thus pose a risk,, when people
are exposed to  toxic levels in  the  air,  water, food^ or contami-
nated soil.  Chemical exposures can  adversely affect the environ-
ment by disrupting the ecology  of surface  waters  or the dynamics
of biological communitie,s.  Furthermore, toxic  chemicals can  so
contaminate ,a natural  resource that future generations can,  for
all practical purposes,  no longer^  use  or  enjoy  it or  must  pay
greatly to do so.    ^,             ''-^                    .

     In order to  examine",potential  impacts to human health  from
environmental exposures  in a  particular  geographical  location,
we perform  a risk  assessment.  , Based on. the National Research
Council's^ recommendations", ^ an  IEMP risk assessment contains  the
following elements:  '•    -..       .      ^.  'f

    o Hazard Identification
      Does the  agent cause the  adverse effect?

   T   For the chemicals '"of; interest,  RID toxicologists and  con-
      tractors  prepare individual  Profile/jreports that  summarize
   •fc the information on animal and human health effects.   Each
      report examines bot^ oral and, inhalation .exposure datd  for
   \   the following  ten health  effect  categories:  .qancer,  liver,
      kidney, reproductive, fetal developmental,  neurobehavioral,
      mutagenicity,  respiratory",  cardiovascular,  and  other.   A
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 weigh,t-of-evidence evaluation  is  provided for  each health
 effect category.   For  cancer,  we use  the EPA  weight-of-
 evidence evaluations  that  are prepared  by  the  Agency's
 Cancer Assessment Group  (GAG)  according to the  1986 cancer
 risk assessment guidelines.3   EPA does  not have weight-of-
 evidence evaluation  schemes   for  the other  health  effect
 categories, so we use ranking  schemes developed specifically
 for our  work.   Our ranking  schemes are currently  being
 reviewed by scientists within and outside  EPA.

o Dose-Response Assessment
  (What is  the relationship between  dose  and incidence  of
  effect in humans?)

  This information is also  provided  in the chemical profile
  reports.  With the  exception of mutagenicity,  a  separate
  evaluation is provided for each of the  health effect cate-
  gories.  For cancer, we use the dose-response evaluations,
  or "unit  risk  factors"  that are prepared by EPA's Cancer
  Assessment Group  (CAG).   For  the  remaining  non-cancer
  health effect  categories,  EPA does not  have a satisfac-
  tory method  for  quantifying  dose-response  relationships.
  Therefore, as  an alternative  we  use  the  EPA  Reference
  Doses (RfDs)  as  benchmarks  to  estimate exposure  levels
  that are  "safe"  and for  which we assume  the  incidence  of
  effects is insignificant.*

o Exposure Assessment
  (What exposuresare  currently experienced or  anticipated
  under different conditions?)

  The IEMP  studies include an assessment   of  environmental
  exposure levels  for  selected  chemicals   in  the media  of
  interest,  usually air and water.   Environmental exposures
  are estimated primarily by modelling.  As feasible,  field
  monitoring is  conducted  and  the  collected  data  are used
  to val.idate  the  modelling.    In  addition   estimates  of
  exposed populations are  made  by  examining  census  data.

0 Risk Characterization
  (What is the estimated incidence of the  adverse effect  in
  a given population?)

  For the environmental media  of  interest,  we  use our expo-
  sure assessment  to  estimate  both  the  concentrations  of
 *In so doing,  IEMP follows  EPA practice.  However,  other
  authorities may  use  other  methods.    For  example,  for
  airborne contaminants.  Threshold Limit Values (TLVs)
  may be more suitable under certain circumstances.
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       specific chemicals and  the  number  of  people  exposed  at
       those concentrations.   We  then link  this  information  to
       our chemical-specific dose-response  assessments  in  order
       to make rough estimates  of the incidence of disease  that
       may occur  above  the  baseline  rate  in the  study  area.

         Note that  because   of  limitations  in  our  ability  to
       quantify dose-response   relationships  for   each  of  the
       eight health  effect  categories,  we  must  analyze  cancer
       differently from the non-cancer health  effects.   For  can-
       cer, we treat the CAG unit  risk  factor as  the  slope  of
       the dose-response curve;  therefore,  we  can  use this value
       to estimate a crude incidence.  For  the non-cancer health
       effect categories, we do not have estimates  of the slopes
       of the dose-response  curves.   Instead,  we have  the RfDs,
       which we . use as  estimates  of exposure  levels  that  are
       "safe", in terms of non-cancer health risks.  So for  non-
       cancer effects,   we  do  not  calculate  the  incidence  of
       effects.  Rather, we  calculate the  number  of people ex-
       posed to  levels  above the  RfDs in  order to estimate how
       many may be at some increased risk.

         The risk characterization also  includes a  discussion of
       the uncertainties  in  the   hazard  identification,  dose-
       response assessment,   and  exposure   assessment.    For  the
       hazard identification,  this  discussion  focuses  on  the
       weight-of-evidence evaluations.  For the dose-response and
       exposure assessments,  the discussion focuses on uncertain-
       ties in the databases and models used.

     During Phase I of our first  geographic project in Philadelphia
and then again in  Baltimore,  we also  relied on priority-setting
methods other than quantitative  risk assessment; e.g.,  the use of
expert judgement to establish relative ranking of issues.

     In order  to perform an IEMP  risk  assessment, as outlined
above, we  rely heavily  on approved  EPA quantitative methods, CAG
unit risk values, RfDs  and other appropriate standards and crite-
ria.  In  addition,  we   often use other  approaches and criteria
to refine our priority  ranking of  issues.  These criteria include
analytical feasibility,  relevance  to  EPA,   state,  and  local pro-
gram objectives,  and the potential for effective response.  These
criteria (which  incorporate  risk  management  perspectives)  are
discussed in Chapter VIII of this  report.

     Bear in mind that  the  objectives of the  IEMP  in the use of
risk assessment procedures are  to allow  for relative comparisons
of potential problems  and to provide  a general  sense of the re-
lative significance of  an issue,  rather than  to make  definitive
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statements about  the  absolute risks posed  by a particular  sub-
stance, source, or pathway.   It must be emphasized that we conduct
risk assessments;  we  do not conduct  epidemiological  studies*
Thus, we  do not,  and cannot  examine  the  disease  rates in  the
local population in order, to correlate health  effects with current
or past environmental  exposures.   Moreover, the  exposure assess-
ments conducted as part of an IEMP are not designed to be used in
nor are they appropriate for an epidemiological study.
                                     "     *
     Although different in their objectives, design and interpre-
tation, risk assessments and epidemiological studies are actually
complementary.  Risk  assessment can  help  to identify populations
and geographic  areas  that  appear to  be at  risk  and  therefore
might be  appropriate  subjects  for  an in-depth  epidemiological
study.  Epidemiological  studies   increase  the scientific  under-
standing of the relationship between exposure and health effects,
thereby strengthening  the basis pf risk  assessment.  Epidemiolo-
gical studies may  also,  in  some   cases, be  useful  for confirming
specific hypotheses suggested by risk assessment.

     Other  qualifications regarding the  use  of  quantitative and
other health risk  assessment  methods are  discussed later in this
appendix.

Phase II Risk Management

     In Phase II,  we  will focus  the resources of  the project on
considerations of  how best  to manage  risk  in  selected  areas.
Risk management  is  the  process  of  evaluating  and  selecting
approaches to  reduce  the risks  identified  through  risk assess-
ment.  Risk  management  considers not  only  the  level  of  risk
posed by a particular  pollutant  or source  of.pollution  but also
factors such as the feasibility and  cost  of control, public pre-
ferences, and  institutional  capabilities.    Setting  priorities
for research or  government  action is  also  a  key 'aspect of risk
management.  The  objectives  of   this  Phase  are to  investigate
control alternatives,   estimate their  efficiency in  controlling
pollution, develop estimates of their cost,  and then assess their
cost-effectiveness; in the Baltimore IEMP it also includes devel-
opment of analytical tools (i.e., a model for helping local govern-
ments establish priorities  for addressing  potential  threats  to
ground-water resources from  underground  storage  tanks)  as' well
as a research plan (the  Harbor blueprint).   Where  necessary,  we
supplement the analysis by developing detailed exposure estimates
and other specific data  required  to  refine  the quantification of
risks assessed in Phase  I.

     The criterion of cost-effectiveness  (i.e., cost per change in
some unit of effectiveness) is generally  expressed as the amount
of human health risk reduced  by alternative controls in relation
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to the  cost  of  implementing  those .controls.   However,  in  some
cases, such comparisons cannot be  made and other economic  crite-
ria or definitions of cost-effectiveness must be used  (e.g.,  the
costs of preventing damage to a resource).

     Even where  mechanisms are  already  in place for controlling
chemical exposures,  an  analysis   of  the  cost-effectiveness  of
these control strategies can be useful to local communities.   An
analysis of the  cost-effectiveness of control  options may  lead
to the identification of control strategies  that attain the  same
level of control for less  cost.
GENERATION OF RISK ESTIMATES

     The following  overview of  methods  for  quantifying  health
risks theoretically applies to both cancer  and  non-cancer  health
effects.  In  practice,  appropriate  quantitative  methods  have
only been  developed   for estimating  carcinogenic  risks.   There-
fore, unless  noted  otherwise,  the  following  discussion  deals
only with estimation  of  carcinogenic  risk  to an  exposed  popula-
tion.

     In IEMP studies,  we  calculate risk using  three measures  of
exposure:  risk  to the most  exposed  individual  (MEI),  risk  to
the average  exposed individual (AEI),  and  the excess  aggregate
population incidence.  We define risk  to the MEI as the increased
probability that an individual chronically exposed to the highest
concentration of one or more chemicals will  have exposure-related
cancer during the  course  of his  or her lifetime.  For  the MEI,
the exposure is calculated as either the highest modelled concen-
tration or the average concentration  obtained  for the  monitoring
site with the highest daily or annual  average monitored value for
one or more chemicals*  We define risk to the AEI as the increas-
ed probability that an individual  exposed to the  area-wide aver-
age concentration  of  .one or  more chemicals will  have  exposure-
related cancer during  the course  of his or  her  lifetime.   Aggre-
gate population  risk  is  the estimate  of  the  increased incidence
of cancer, above the  background rate,  in an  exposed population.
We use the standard EPA assumption that exposure is for 70 years.
Thus, elsewhere when we refer  to "lifetime risk" or "70-year life-
time", this means 70 years of exposure.   A more detailed discussion
of our assumptions  and approach  for  calculating  these  risks  is
provided later in this Appendix.

     For a given population,  the  IEMP  risk assessment  involves
linking estimates  of  chemical potency,  derived from  animal and
human health  effects  data,  with  estimates or measurements  of
area-wide contamination or  exposure  levels.   A  relatively high
degree of uncertainty unavoidably underlies  this  approach.   In
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most cases, the risk estimates cannot easily be  verified  or  dis-
proven by observation.  The approach is  useful,  however,  because
it is straightforward and allows application of  the  most  current
scientific information to the analysis of  adverse health  effects
from current and projected exposures.

     The two key  elements  in  estimating  health  risk are:  1)  the
calculation of the potency  of  a  chemical,  and 2) the  determina-
tion of the level of exposure  to  that  chemical.

1. Estimating Potency

   A. Carcinogens

   Potency  is estimated from  an  analysis of relevant animal   and
human  (i.e., occupational, epidemiological) data concerning  the
toxicity of a chemical.   At EPA,   data are  obtained  from the  open
literature and from proprietary studies  submitted to the  Agency.

   Chemical potency is determined by:  1)  evaluating  qualitatively
the preponderance (or weight)  of evidence  that a chemical causes
the adverse health effect in question;  and, if  so,  (2)  estimating
quantitatively the  relationship  between  the dose  (that  is,  the
amount of  chemical  an  animal or  person  is  to exposed  over  a
period of time) and the incidence of the  effect within an exposed
population of a given size.  The latter  "dose-response relation-
ship" describes the potency of the  chemical.   That  is, the lower
the threshold  and the  steeper the slope  of  the  dose-response
curve, the more potent the  chemical.  For  assessing  carcinogenic
risks, potency estimates can be used to  relate the  levels of ex-
posure to  the  probability that  individual(s)  will  have  cancer.

   The EPA  Cancer Assessment  Group  (CAG)  calculates  chemical-
specific cancer potency values called "unit risk" estimates.   We
use these unit risk estimates  in  our  IEMP studies and many  Pro-
gram Offices throughout EPA also use  these values- for  a  variety
of risk assessment and risk management activities.

   o Qualitative evaluation

     The qualitative,  or  weight-of-evidence evaluation involves
     reviewing the scientific  literature,  both human and  animal,
     to establish the  sufficiency  of evidence  for  a  chemical's
     carcinogenic potential in humans.   This  evaluation of  the
     weight-of-evidence for a causal  association   between  the
     chemical exposure and  cancer  is an  important  part  of  risk
     assessment.  It is necessary because  the  extent and  quality
     of chemical-specific databases rarely allow for  an  unambi-
     guous determination of carcinogenic  potential.
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     Two evaluation schemes  are available  .for  assessing  cancer
weight-of-evidence.   One was  developed by the  International
Agency for Research on Cancer  (IARC)  and the  other  was developed
by EPA.  The  EPA  scheme  is  a modification of  the IARC  system.
All chemicals evaluated for  carcinogenicity by .EPA1s  GAG  are now
classified according to the EPA scheme.

     Briefly, the IARC scheme has the following three'categories: ^

     Group I;   Known Human Carcinogen.„  This   category  is  used
only when  there  is  sufficient  evidence  from  epidemiological
studies to support a  causal  association between the exposure and
cancer.

     Group II;   Probable  Human  Carcinogen.   This category
includes exposures for  which,   at  one  extreme,  the  evidence of
human carcinogenicity  is  almost  "sufficient" and  at the  other
extreme, it is "inadequate".   To reflect this  range, the category
is divided into  Group IIA and  Group I IB to  indicate higher and
lower degrees of evidence, respectively.

     Group III;  This category includes exposures that can not be
classified as to their carcinogenicity in humans.

The EPA scheme has,the following five categories: ^

     Group A;  Human Carcinogen.  This category is used only when
there is  sufficient  evidence  from  epidemiological   studies  to
support a  causal association between exposure  to  the agent and
cancer in humans.

     Group B;  Probable Human Carcinogen.  This category includes
agents for which the evidence  based on  epidemiological  studies
is "limited" and agents for which  the  evidence based on animal
studies is "sufficient".  To reflect this range,  the  category is
divided into Group Bl and Group B2,  indicating  higher and  lower
degrees of  evidence,  respectively.   Group  Bl   has  agents  with
"limited" evidence  from epidemiological  studies.   Group  B2 has
agents with "sufficient" evidence from animal studies  and "inade-
quate" evidence or "no data" from epidemiological studies.

     Group C;  Possible Human Carcinogen.  This  category  is used
for agents with  "limited"  evidence  of carcinogenicity in animals
and an absence of human data.

     Group  D;  Not Classifiable as to Human Carcinogenicity.  This
category is used for agents  with  "inadequate"  human and animal
evidence of carcinogenicity  or for  which no  data are available.
                               A-17

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     Group E;   Evidence  of Non-Carcinoqenicity for  Humans.

     This category is  used  for agents that  show no  evidence  of
carcinogenicity in at least  two adequate animal tests in different
species or in  both adequate epidemiological and animal  studies.
This designation  is  based  on the  available  evidence and  should
not be interpreted as a definitive conclusion that  the agent will
not be a carcinogen under any circumstances.

Presently, there is  no  similar  scheme for assessing  the  weight-
of-evidence for agents causing non-cancer health effects.3

     0 Quantitative evaluation

       In general,  the  EPA  Carcinogen  Assessment  Group  (CAG)
       estimates the cancer  potency of agents that  are classified
       Group B  and higher.    Potency  is  expressed  as the  "unit
       risk". This unit risk  estimate  for  an air or water pollu-
       tant is defined  as "the  incremental  lifetime  cancer risk
       occurring in a hypothetical population in which  all  indi-
       viduals are  exposed   continously   from  birth  throughout
       their lifetimes to a  concentration of  1 ug/rn-^ of the agent
       in the  air  they  breathe,  or to 1  ug/L  in the  water they
       drink.  This calculation is done to estimate in quantita-
       tive terms the impact of the agent  as a  carcinogen.   Unit
       risk estimates are used  for two purposes: (1)  to  compare
       the carcinogenic potency of several agents with each other,
       and (2) to give  a crude indication  of the population risk
       that might"  be  associated  with  air or  water  exposure  to
       these agents,  if the  actual exposures  are known."4

     0 Key simplifying assumptions of  the quantitative evaluation

       In most cases, CAG uses a  so-called linearized multistage
       model  to  calculate   chemical-specific cancer  potency  or
       unit risk  estimates.   A mathematical model  is  needed  in
       order to calculate the unit risk factor because animal and
       human carcinogenicity data  are always  associated with expo-
       sure levels that are  much  higher than  those  normally found
       in environmental seittinqs.  Therefore,  in order  to  esti-
       mate potential cancer risk  for  the  low  exposure.levels  of
       concern, it is necessary to extrapolate  from data associ-
       ated with high  exposures.   This  is  done through  the  use
       of appropriate models.

       In explaining their choice of model, CAG notes the follow-
       ing important considerations:

            "The unit risk  estimate  represents  an "extrapolation
       below the dose range  of experimental  data.   There  is cur-
       rently no  solid  scientific basis  for  any  mathematical
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       extrapolation model that relates exposure to cancer risk
       at the extremely low concentrations,...  that must be dealt
       with in evaluating environmental hazards.  For practical
       reasons the correspondingly low levels of risk cannot be
       measured directly either by animal experiments or by epi-
       demiological studies.  Low-dose extrapolation must, there-
       fore, be based on current understanding of the mechanisms
       of carcinogenesis.  At the present time the dominant view
       of the carcinogenic process involves the concept that most
       cancer-causing agents also cause irreversible damage to
       DNA.  This position is based in part on the fact that a
       very large proportion of agents that cause cancer are
       also mutagenic.  There is reason to expect that the quan-
       tal response that is characteristic of mutagenesis is
       associated with a linear (at low doses) nonthreshold
       dose-response relationship.  Indeed, there is substantial
       evidence from mutagenicity studies with both ionizing
       radiation and a wide variety of chemicals that this type
       of dose-response model is the appropriate one to use.  This
       is particularly true at the lower end of the dose-response
       curve; at high doses, there can be an upward curvature,
       probably reflecting the effects of multistage processes
       on the mutagenic response.  The low-dose linear nonthres-
       hold dose-response relationship is also consistent with
       the relatively few epidemiologic studies of cancer respon-
       ses to specific agents that contain enough information to
       make the evaluation possible (e.g., radiation-induced leu-
       kemia, breast and thyroid cancer, skin cancer induced by
       arsenic in drinking water, liver cancer induced by afla-
       toxins in the diet).  Some supporting evidence also exists
       from animal experiments (e.g., the initiation stage of the
       two-stage carcinogenesis model in rat liver and mouse skin).

     Because its scientific basis, although limited, is the best
of any of the current mathematical models, the nonthreshold model,
which is linear at low doses, has been adopted as the primary   "~" ^
basis for risk extrapolation to low levels of the dose-response
relationship.  The risk estimates made with such a model should
be regarded as conservative, representing a plausible upper limit
for the risk; i.e., the true risk is not likely to be higher than
the estimate, but it could be, and probably is, lower.
                                      -'
     For several reasons, the risk estimate based on animal bioas-
says is only an approximate indication of the absolute risk in
populations exposed to known c'arcinogen concentrations.  First,
there are important species differences in uptake, metabolism,
and organ distribution of carcinogens, as well as species diffe-
rences in target site susceptibility, immunological response,
hormone function, dietary factors, and disease.  Second,  the
concept of equivalent doses for humans compared to animals on a
                              A-19

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ing/surface area basis is virtually without experimental verifica-
tion as regards carcinogenic response.  Finally, human popula-
tions are variable with respect to genetic constitution and
diet, living environment, activity patterns, and other cultural
factors.

     The risk estimate can give a rough indication of the rela-
tive potency of a given agent compared with other carcinogens.
Such estimates are, of course, more reliable when the comparisons
are based on studies in which the test species, strain,  sex,
and routes of exposure are similar.

     The mathematical formulation chosen to describe the linear
(at  low  dose) nonthreshold dose-response relationship is the
linearized multistage model.  This model employs enough arbitrary
constants to be able to fit almost any monotonically increasing
dose-response data, and it incorporates a procedure for estima-
ting the largest possible linear slope (in the 95% confidence
limit sense) at low extrapolated doses that is consistent with
the data at all dose levels of the experiment." 4

     The EPA Carcinogen Risk Assessment Guidelines indicate the
following concerning the choice of extrapolation model:

     "The Agency will review each assessment as to the evidence
on carcinogenesis mechanisms and other biological or statistical
extrapolation model.  ...A rationale will be included to justify
the use of the chosen model.  In the absence of adequate informa-
tion to the contrary, the linearized multistage procedure leads
to a plausible upper limit to the risk that is consistent with
some proposed mechanisms of carcinogenesis.  Such an estimate,
however, does not necessarily give a realistic prediction of the
risk.  The true value of the risk is unknown, and may be as low
as zero."3

     B. Mutagens

     In the IEMP studies, we restrict our evaluation of mutagen-
icity to a qualitative assessment.  We simply indicate if the
chemical is considered to be a mutagen or if there is insuffi-
cient data to make such a determination.  Most of the experimen-
tal dates addressing mutagenicity involve in vitro testing of
mammalian cell cultures and non-mammalian organisms such as
bacteria.  At present,  we do not have methodologiess for using
these kinds of data to calculate dose-response curves amd quanti-
fy risk to humans.  EPA  assumes that a dose-response relation-
ship for mutagenicity,  like carcinogenicity, would have no thres-
hold; therefore, any exposure level would be associated with
some degree of risk.  Evidence of mutagenicity often, but not
always, suggests carcinogenic potential.
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     C.  Non-Carcinogens

     Chemicals that give rise to toxic endpoints other than cancer
and gene  mutations  are  often  referred  to by  EPA as  "systemic
toxicants" because they  affect the  functioning of various  organ
system, such  as  liver,  kidney,  cardiovascular,  and  respiratory
systems.  Generally, based on our understanding  of physiological
mechanisms, systemic  toxicants  are  treated as  if there  is  an
identifiable exposure threshold (both for  the  individual  and for
the population) below  which  adverse effects are not  observable.
From the  viewpoint  of risk assessment and  risk  management,  this
characteristic distinguishes systemic toxicity  from  carcinogeni-
city and  mutagenicity,  since  the  latter two are usually  treated
as non-threshold processes.

     Because of this concept of identifiable thresholds, systemic
effects traditionally have been evaluated by EPA through the cal-
culation of  "safe"  exposure  levels.   This is  unlike  EPA's  ap-
proach for  evaluating  carcinogens,   for  which all  exposures  are
assumed to  involve  some  measure  of risk.   For many  years,  the
concepts of "acceptable  daily intake" (ADI) .and  "margin of safe-
ty" have  been at  the heart of EPA's approach  to risk assessment
for non-cancer health  effects.   Although  there  are  limits  to
some of these approaches, EPA is often called upon to apply these
concepts when  making  and explaining  decisions  concerning  the
significance to human health of certain chemical exposures in the
environment.  Thus,  the  threshold concept  for  non-cancer  effects
is extremely important in the regulatory and risk management con-
text.

     More recently,  the  Agency  has  tried  to  come to  grips with
some of the technical and philosophical issues inherent in defin-
ing a  "safe"  exposure  level  for systemic  toxicants.   As  an out-?
growth of this effort,  the concept  of  the "reference dose" (RfD)
has been  recommended  to  replace  that of  the ADI.   The  RfD  is
calculated in the same manner as an ADI;  however, it  is  viewed
as a .benchmark level  without  the  value-laden  connotations  of
absolute safety or acceptability versus absolute unacceptability.
Thus, exposures that are less  than  the RfD are  not  likely to be
associated with non-cancer health effects  and  are therefore less
likely to be of regulatory concern.   Conversely, as the frequency
of exposures exceeding the RfD  increases and as the  size  of the
excess increases,  the probability  also  increases that  adverse
effects may be  observed  in  a human population.   Nonetheless,  a
clear conclusion  cannot  be  categorically  drawn that  all doses
below the RfD are "acceptable"  and that all doses  in excess  of
the RfD are "unacceptable."5

     To date,  the Agency's  calculation  and use of ADIs and RfDs
has been applied  only  to oral exposure  routes,  such as drinking
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water and food.  EPA has an established methodology for calculat-
ing oral  RfDs  and  there are values for approximately  400  chemi-
cals.  In contrast,  the Agency does  not  have a  methodology  for
calculating similar  benchmark  levels  for  inhalation  exposures.

     EPA has not yet established  a procedure for estimating such
benchmark values for  chronic inhalation exposures;  a methodology
is under  development by  a special  committee in FY'87 and  the
values will be  called inhalation  RfDs.  Thus,  with the exception
of the  six  or  seven heavily  studied criteria air  pollutants
(ozone, carbon monoxide, sulfur oxides,  etc.) there are no bench-
mark values for chronic inhalation exposures that are appropriate
for use in risk assessment.  Because the Agency's RfDs are calcu-
lated for lifetime oral  exposures  only, and IEMP studies examine
both oral and  inhalation exposure routes, it has  been necessary
for us to estimate IEMP  benchmark  levels for  inhalation exposures.

     IEMP studies rely  on  EPA  oral RfDs and on other "threshold"
values computed by our toxicologists and consultants.  Our "thres-
holds" for various non-cancer effects have been calculated employ-
ing the same methodology  used  to  estimate oral RfDs.  Highlights
of the RfD methodology are as follows:

       RfDs are calculated by collecting the available
    animal and human data, noting the various dose
    levels (in milligrams per Kg body weight per day)
    at which different non-cancer health effects are
    seen,  and identifying the highest NOEL (No Observed  .
    Effect Level).   The highest NOEL represents the
    highest dose at which biologically or statistically
    significant effects were not seen.  The scientists
    also try to identify the LOEL  (Lowest  Observed
    Effect Level),   which is the lowest dose at which a
    biologically   or  statistically  significant'  non
    cancer effect was seen.

       Many different NOELs and LOELs can be identified
    for   each  chemical,    depending  on  the   doses
    selected,   the  spacing  between the doses and  the
    health   effects  examined  and  reported  by   the
    researchers.   Toxicological   research   is   very
    expensive and each experiment cannot be  exhaustive
    in  terms  of  the number of doses tested  and  the
    number    of    effects    studied.      Similarily,
    epidemiological  research is expensive and  subject
    to many problems with both measurement of exposures
    and  identification  of  exposure-related  effects.
    This problem introduces a degree of uncertainty  in
    the identification of the "true" NOEL and LOEL of a
    chemical  and  this  uncertainty is carried  through
    the calculation of the RfD.
                               A-22
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        The  RfD is calculated by dividing fche  highest
    reliable   NOEL  (or  lowest  reliable   LOEL,    if
    appropriate) by uncertainty factors.   The selection
    of   appropriate  uncertainty  factors  is    based,
    primarily,  on  the nature of the study from   which
    the NOEL, or LOEL,   was derived.   Each factor has a
    value  from 1-10 and represents an extra degree  of
    uncertainty  to account for:  1)  extrapolation from
    the average human to sensitive members^of the human
    population,   2)  extrapolation  from Jthe  average
    animal to the average human,  3)  extrapolation from
    subchronic  exposures to chronic exposures  and  4)
    extrapolation from the LOEL to the NOEL.5

     By definition, the RfD is based on the critical non-cancer
health effect.  This is the effect first seen as  exposures in-
crease above zero.  Since IEMP studies often examine exposures
that are above the RfD for a particular chemical, it would be
valuable to know what kind of effect(s) might be  seen as expo-
sures get higher and higher above the RfD.  This  type of infor-
mation is not obtainable from the single RfD that is calculated
for a chemical.  To help solve this problem, we have taken the
following approach in our IEMP studies:

       1)  non-cancer health effects are divided  into the six
    broad health effect categories of liver, kidney, reproduc-
    tive, neurobehavioral, fetal developmental, and other.  The
    category "other" includes a variety of effects such  as cardi-
    ovascular, respiratory, and gastrointestinal.

       2) for each chemical of interest, examine  both the oral
    and inhalation data for humans and animals.

       3) using the RfD methodology,  and route-specific  toxicity
    data, we calculate a separate inhalation and  oral  "threshold"
    for each of the six health effect categories.  Obviously, the
    more toxic a chemical, and the more it has  been studied, the
    more  health effect   categories  for  which   we  can esti-
    mate "thresholds".

2.) Assessing the Level of Exposure

     The second key element (see p. A-16) in estimating health risk
is determining the level of exposure to that chemical.  Most of
our exposure assessments attempt to estimate ambient concentra-
tions of substances in the air and drinking water.  We then make
certain assumptions about how ambient concentrations relate to
actual human exposure or dose level.  For example, we take no
account of population mobility.  These assumptions—the exposure
constants regarding how much air a person breathes or water he
or she drinks—are described below.
                               A-23

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     We estimate ambient concentrations in two ways:  direct moni-
toring or simulation modelling.  There are a number of advantages
to the modelling of ambient concentrations over direct monitoring
alone:

      o Modelling  may  provide the only way  to  estimate  ambient
        concentrations under alternative exposure scenarios.

      o Modelling  can  take  into account the  geographic variabi-
        lity of a  large  area.   Because monitoring data are often
        from  a  few  specific points,   they  best  serve  as refe-
        rence points for evaluating the performance of air dis-
        persion models.

      o Modelling  is often less costly than extensive monitoring.

      o Modelling  enables predictions  of exposures  in any loca-
        tion (and,  in  particular, the  location of  the  most ex-
        posed individual),  whereas monitoring  can  only provide
        an indication  of the  exposures in  the vicinity  of the
        sampling sites.

      o Modelling  links  concentration  estimates,  and hence expo-
        sures, to  sources.  Such  source information is important
        as a  risk  management tool in  that it  allows us to esti-
        mate the  impact of  various  pollution control  options.

      o For  some pollutants,  there  are no  accepted methods for
        monitoring them in ambient air.

     On the other hand, constructing a  model of  pollutant releases
and resultant ambient  concentrations involves  making assumptions
about the important processes  between  pollutant source and human
receptor.  Building such a  model thus  requires an understanding
of those  processes,  which  is not  necessary if  one  can  simply
monitor ambient concentrations directly.

     When carrying out an IEMP,  we first employ existing data-
bases which have   been  reviewed  for  currency  and  quality.   We
conduct monitoring  as   an  adjunct  as  resources  allow and use
monitoring data to verify ambient  concentrations estimated from
our models.    Under  certain  circumstances,  such  as  situations
where we do not  know sources and  emissions,  monitoring data are
crucial for estimating  exposures.   Furthermore,  an advantage of
reliable, long-term monitoring  data is that they provide  a more
direct and often simpler means  of estimating ambient conditions.
Even with direct  monitoring,  however,  interpretation  of results
can be difficult if data are limited or if lab  or.sample contami-
nation is suspected.
                               A-24

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     The  key steps in modelling exposures are:

       (1) estimating the number of sources of emissions;

       (2) gathering data on emissions (in g/sec.)  of target
           compounds from selected sources;

       (3) gathering release specifications for chemical emis-
           sions, such as building dimensions, stack height,
           location of release points;

       (4) characterizing the processes and pathways by which a
           pollutant is transported in air, soil,  and water,
           including the speed of transport, the extent of dilu-
           tion or dispersion, and any chemical transformation
           the pollutant might undergo (such as degradation to
           a nontoxic, or possibly even more toxic form).

       (5) locating receptor sites; and

       (6) assigning populations to receptor sites.

     .We try to estimate resulting ambient concentrations at
various distances from the source.   Estimating long-term average
concentration levels, which are of concern for evaluating chronic
health impacts, is simpler than short-term modeling, which must
take greater account of variations in meteorological conditions.
          *                                     ' •

RISK CHARACTERIZATION

     As noted- on pages A-12-13, risk characterization is the part
of risk assessment that brings together the exposure assessment
and the dose-response information in order to estimate the inci-
dence of an adverse effect in a given population.   As further
noted, because of limitations in our ability to quantify dose-
response relationships for each of our health effect categories,
we  must analyze cancer differently from the non-cancer health
effects.  For cancer, we treat the GAG unit risk factor as the
slope of the dose-response curve; therefore, we can use this
value with the results of our".-exposure assessment to estimate a
crude incidence.  For the non-cancer health effect categories,
we do not have estimates of the slopes of the dose-response
curves.  Instead, we have RfDs and our own  "thresholds" for each
of the effect categories.  Therefore, for non-cancer, instead of
calculating the incidence of  effects, we calculate the number of
people exposed to levels of chemicals that are above the RfDs and
other "thresholds" in order to estimate how many may be at  some
increased health risk.  For each chemical of  interest, we examine
each of the six non-cancer health effect categories separately.
                               A-25

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     If  exposures to  a  substance are below the  threshold  for a
particular non-cancer  health  effect  category,   then  we  expect
little increased  risk  of effect  from that substance.   If  expo-
sures exceed  the  estimated threshold  for a  particular  health
effect category,  we  then indicate  the possibility  of  increased
risk of  that  effect  and  try to estimate the size of the popula-
tion exposed  to  such concentrations.   Exposures  exceeding  an
estimated threshold  are  generally more appropriate  subjects  for
further  investigation.

     Note that the use of GAG  potency estimates  to evaluate can-
cer risk and  the  use of RfDs  to  identify  exposures  of  potential
concern  for non-cancer health  effects are relatively straightfor-
ward practices and have been used throughout EPA for many years.

Risk Characterization as Applied to an IEMP

     In  IEM studies,  we calculate  cancer risk using three measures
of exposures:   risk  to the most  exposed individual  (MEI),  risk
to the average exposed individual (AEI), and the excess  aggregate
population incidence.  For all calculations, we use the following
standard assumptions:  1) the  average  lifetime  is 70  years,  2)
the average adult breathes  20 cubic meters of  air  per day,  and
3) the average adult drinks 2  liters of water per day.

     We  express individual  risk  as  either MEI risk  or  AEI risk.
We define risk  to the MEI  as  the  increased probability that an
individual exposed to  the  highest  concentration of one  or more
chemicals will have  exposure-related cancer during the  course of
his or her lifetime.   For the  MEI,  the  exposure  is calculated as
either the highest modelled concentration  or the average concen-
tration obtained  for the  monitoring  site  with the highest daily
or annual average monitored value for one  or more chemicals.   We
define risk to the AEI as the  increased probability that an indi-
vidual exposed to the  areawide average  concentration  of  one or
more chemicals will  contract  cancer  during the  course  of his or
her lifetime.   Aggregate population risk is the  estimate  of the
increased incidence  of cancer, above the background  rate,  in an
exposed population.    ,

     To estimate  the risk  to the  most  exposed  individual,  we
typically need to know how far an individual lives from the maxi-
mum pollutant concentration near  a  source.  To  estimate average
individual risk,   we  estimate  an  average  pollutant concentration
to determine exposure.  To estimate  population risk, we  must iden-
tify the number of people exposed to a given pollutant concentra-
tion.   In our exposure estimates,  we are assuming that people are
exposed to outdoor ambient  air concentrations  24 hours  a day for
a lifetime.   In reality,  people spend most of their time indoors,
either at home  or  at  work.   While  our   assumption  overstates
                               A-26

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actual exposure to outdoor air, the' bias  introduced by this pro-
cedure may not  be too  great,  since  recent  EPA (TEAM)  studies
show that many  outdoor  air  contaminants  are also  found  indoors
at equal  or   greater concentrations.   This  represents  current
standard practice at EPA.

     Under these  assumptions  and  exposure  scenarios,  lifetime
cancer risk to  the  exposed  individual  is  simply the  product  of
exposure and potency:

             R           =      Ex       P             (1)
    individual  risk         exposure        potency factor

     As discussed above,  exposure is the product of the  ambient
concentration of the pollutant  in the  medium of.concern  (air  or
drinking water) and exposure  constants  (i.e., the standard assump-
tions of  body  weight,  breathing  rate and  water  consumption):

    E         =             Y          x             Z        (2)
 exposure        ambient concentration       exposure constants
                 in medium of  concern

and

       R                Y       x      Z        x          P     (3)
   individual        ambient        exposure            potency
     risk        cone, in medium    constants           factor
                    of concern

                       SAMPLE CALCULATION

     The following is a simple example to illustrate how we would
calculate the lifetime  risk  to the MEI, as  well as the lifetime
risk to a population, associated  with  an  ambient air exposure of
ten micrograms  per  cubic meter  (ug/m3)   of benzene.   We  have
divided the geographic  area  of concern  into sections which  we
will call "grids."

     In our example,  we have  four grid sections.   For each grid, we
have the following average ambient air concentrations and popula-
tion data:

                          Annual Average

                              Benzene
                           Concentration              Exposed
    Grid f                     (ug/m3)                Population

      1                         10                     20,000
      2                          8                     30,000
      3                           8                     25,000
      4                          5                     25,000


                               A-27

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     The MEI risk of cancer for an individual exposed to 10 ug/m3
of benzene  in the air (the highest benzene exposure) is calculat-
ed by  using equation (3).  The  ambient concentration  (Y)  is  10
ug/m3, which is  equivalent to  0.01  milligrams per  cubic meter or
0.01 mg/m3.  The .potency  factor (P) for  inhaled  benzene,  devel-
oped by  EPA's   Carcinogenic  Assessment  Group  (GAG),  is  0.029
(mg/kg/day)-1.   This value means that  an  individual inhaling one
milligram  (mg) of benzene per  kilogram body weight per day for a
lifetime has  an estimated  increased  probability   of  developing
cancer of  about three  in  one  hundred  (upper-bound  estimate).

     Using equation  (3)   and  the  maximum  ambient  concentration
value of 0.01 mg/m3, we calculate the risk to the MEI as follows:

 R      =     Y         x       Z    .      x       P          (4)
MEI       Avg. annual       exposure           potency
Risk     ambient cone.      constants          factor

where, the  exposure  constants  (Z)  are  adult body  weight (70 kg.)
and adult breathing rate  (20 m3/day)

therefore,

 R  = 0.01 mg/m3 x  (20 m3/day x 1/70 kg)  x 0.029 (mg/kg/day)-1
    = 8.3 x 10-5

The lifetime upper-bound  estimate  of risk to the  MEI (R) in this
example is  8.3   x 10-5  or roughly eight  chances  in  100,000  of
developing cancer over a  lifetime given constant exposure, to 0.01
mg/m3 per day.

     The risk to the  average  exposed  individual  (AEI)  is  calcu-
lated the  same   way, using  an average  exposure determined  from
either monitoring data or air dispersion models.

     The final step  in  our example  is  to estimate the increased
incidence of  cancer in  the  total  population in  our  four  grid
geographic area.   To do this,  we multiply the  risk to the  AEI in
each grid  by  the number  of people  in that  grid.   We  then sum
these estimates  of  incidence  across all  grids to  calculate the
lifetime aggregate  incidence  of  cancer  for  our  four  .grids.

     Generally,   EPA presents incidence  as the  expected number of
excess cancer cases per year.   Dividing the upper-bound lifetime
estimate by  70,  we  arrive  at  the  upper-bound  estimate  of the
annual average number of excess cancer cases in the population of
concern.

     We estimate individual and  population risks  from ingestion
of drinking water in exactly  the same way  we  estimate the risks
from inhalation.   The only difference is that the potency factors
                               A-28

-------
have different values  and  we use the water  consumption exposure
constant of 2 liters/ day.   Because the potency of a chemical may
differ for different routes of exposure, we  must use the potency
factor that is appropriate for ingestion.   This potency factor is
provided to us by the Carcinogen Assessment Group.  Concentrations
of selected chemicals in the drinking water are measured or esti-
mated and then  used with  the oral potency  factors  in  equation
(3) to estimate  risk.   We  calculate both maximum individual risk
and aggregate excess incidence  in a  population in the  same way
indicated in our four grid example.

Risk Characterization as Applied to the Baltimore IEMP

     The Baltimore  Phase  I activities  emphasized  cancer  as the
primary health effect of concern  but some attention was given to
non-cancer effects  of  chemicals  that were addressed  as carcino-
gens.  In Phase II, we will more broadly consider noncarcinogenic
effects to the extent that available  data will allow.  We empha-
sized cancer in Phase I because the public has expressed frequent
concern about the possible link between exposure to environmental
pollution and the incidence of cancer Also, the quantitative risk
assessment methodology for cancer has more scientific credibility
within EPA  than  do similar methods  for  assessing  non-cancer
effects.
INTERPRETING RISK ASSESSMENT RESULTS

     The  estimates of  individual health risk and aggregate inc-
idence from  exposure to toxics should not be interpreted as pre-
cise or absolute estimates of future health effects.  The simpli-
fying assumptions  and uncertainties  in both the  toxicology and
exposure components are simply  too  great to justify a high level
of confidence in the precision of the results.

     The potency and  the  threshold  estimates used  in  this study
are consistently  conservative in the direction of overestimating
risk; they may  overestimate the likely  effects  of chemical expo-
sure but are  unlikely to underestimate  them.   Such an estimate,
however, does not necessarily give  a realistic prediction of the
risk.  The true value  of  the risk is unknown,  and  may be as low
as zero."  This leads  to  assessments that have biases for health
protection when the results are used.   By contrast, our exposure
estimates are not  as  clearly conservative;  some assumptions are
conservative while others are our best  guess of an actual value.
Overall, we have tried  to be  somewhat  conservative  in our expo-
sure assessments, as  is appropriate  in a priority-setting exer-
cise.  It is important to read the detailed chapters carefully to
understand what confidence to place  in a particular  risk estimate.
                               A-29

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     On the  other hand,  we  may understate  risks to  the  extent
that we do  not estimate  exposure and risks from  all  sources and
pollutants that may have toxic effects.  We have tried to identi-
fy the  sources and  pollutants  of  greatest  concern and  address
those that  data  and methods allow  us to cover.   We  acknowledge
that we have not addressed all sources and pollutants.

     Because of  the uncertainties  involved,  the  results  should
not be  interpreted  too literally.   For  example,  one  should not
conclude that  a  source projected to cause three  cases of cancer
per year is  clearly worse than  a .source projected to cause two
cases; given the  overall  uncertainty of the  analysis,  these two
results are  indistinguishable.   On  the other hand, for example,
it is reasonable to conclude that a source projected to result in
one case per year  represents less  risk to the  population  than a
source projected  to  result in ten  cases per year.  Despite the
uncertainties,  our risk estimates are  useful  for roughly assess-
ing the potential magnitude  of the  overall  risks from particular
pollutants, sources,  and  pathways;   comparing  issues  with  one
another; and setting priorities among  environmental   issues and
concerns.
                               A-30

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                 REFERENCES FOR APPENDIX A
1.   National Research Council (1983).   Risk Assessment in the
Federal government:   Managing  the Process.   Committee  on  the
Institutional Means  for Assessment  of Risks  to Public  Health,
Commission on Life Sciences, national Academy of Sciences.
National Academy Press, Washington, D.C.

2.   International Agency for Research on Cancer (1982).  IARC
MONOGRAPHS on the  EVALUATION  OF THE CARCINOGENIC RISK  OF CHEMI-
CALS TO  HUMANS.   World Health  Organization,  Volumes  1  to  29,
Supplement 4, pp. 13, 14.

3.  U.S. Environmental  Protection  Agency  (1986).   Guidelines  for
Carcingenic Risk Assessment.  Federal Register, Vol. 51, No. 185,
33993 - 34003.

4.  U.S. Environmental  Protection  Agency  (1985).   Health Assess-
ment Document for 1,2-Dichloroethane (Ethylene Dichloride).
Office of Health  and Environmental Assessment;  Washington,  D.C.
pp. 9-235 to 9-241.

5.  U.S. Environmental Protection Agency (1986).  Reference Doses
(RfD):  Description  and Use  in Health Risk  Assessments.  Draft
prepared by  the  RfD  Workgroup  for the  Risk Assessment Forum,
May 1986.
                               A-31

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            APPENDIX B
       LIST OF ISSUE PAPERS
SAMPLE ISSUE PAPER:  SEPTIC TANKS

-------
                   List Of Phase I Issue Papers
                          Developed For
                   Technical Advisory Committee
Benzene

Combustion/Incinerator

Chromium in/around Baltimore Harbor(4/24/85)

Ground-water Resource Degradation Ranking for Chromium in
    the Area around Baltimore Harbor(4/25/85)

Landfills

Multi-media Metals

 -Addendum to Multi-media Metals

Pesticides

Publicly Owned Sewage Treatment Facilities

Septic Tanks

Surface Impoundments in the Baltimore Study Area

Water Discharges to Baltimore Harbor
Baltimore Health Data

Note Regarding Health Scores

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         BALTIMORE IEMP ISSUE PAPER.  SEPTIC TANKS
SUMMARY

     This  issue paper explores the impacts of ground water
contamination by septic tank systems in the IEMP Baltimore study
area.  About 12% of the households in Baltimore county and 32% of
the households in Anne Arundel county dispose of domestic wastes
in septic  tanks; most of these households use private wells to
supply drinking water.  Septic tanks are not used in Baltimore
City.

     In Baltimore County both the coastal plain and piedmont
regions have experienced localized groundwater contamination from
septic tanks.  The greatest risk appears to be from the improper
disposal of chlorinated solvents, particularly in areas of the
piedmont with fractured ground-water flow.  In a few isolated
cases ground-water concentrations of trichloroethylene from sep-
tic tanks  have reached concentrations as high as 47 ug/L.  Life-
time exposure to this concentration would be associated with
predicted  upper bound cancer risks exceeding 1 x 10~5; however,
contaminated wells in this area are no longer used as sources of
drinking water.

     In Anne Arundel  County the far eastern regions along
Chesapeake Bay are at greatest risk from septic tank use.  In
the Mayo Peninsula area nitrate concentrations more than.two
times the  drinking water standard of 10 mg/L have been found.  It
is difficult to quantify the risks from these exposures, but it
is clear that infants ingesting this water are at increased risk
of methemeglobinemia.  This area is characterized by a shallow
water table, high septic tank density, and low soil permeabili-
ties .  Contamination of drinking water wells by septic tanks
does not appear to be a major problem in other areas of the
county.

     In some parts of the U.S., septic tank leachate fouls
streams, but this is not recognized as a problem in the Baltimore
study area.

     Although bacterial and viral contamination from septi9 tanks
is probably one of the most widespread pollution problems in the
area, this analysis does not include microbial pathogens.
SOURCE CHARACTERISTICS AND POLLUTANTS

     Septic tank systems consist of a tank, connected to a local
dwelling or set .of dwellings, which receives the raw wastes for
treatment by sedimentation, flotation and anaerobic biological
degradation; and a system of open-jointed or perforated pipes


                               B-l

-------
which take the  effluent  from the tank, and  distribute  it  through
the soil for treatment via oxidation and  microbial degradation or
adsorption.  As such, the  system  is designed  to  release  contami-
nants to the subsurface as a  generally efficient means of efflu-
ent treatment.  However,  in situations where the treatment and/or
assimilative capacity of the  soil  is exceeded these contaminants
can pollute ground water.

     Contaminants  released  from  septic  tank  systems  can  be
classified into two categories.  The first are contaminants which
are natural  components  of  biological and  household  wastes  and
includes the following:

     o  nutrients  and  other  dissolved   materials,  particularly
        nitrates, and

     o  microbial pathogens  (bacteria and viruses), which are not
        being considered in this analysis.

The second  category  of contaminants  are those introduced to the
system through  septic  tank cleaning and  the disposal of consumer
products or  industrial wastes.   Unlike  contaminants in the first
group, these  pollutants  are  typically   chlorinated  organic sol-
vents used  for household  cleaning  or industrial degreasing pro-
cesses, and  are not  always present  in   the  household effluent.
The most  common of  these solvents are probably  trichloroethylene
and methylene  chloride;  we limit the project discussion  of sol-
vents to these  two.

     Contaminants from  both  of the  above  categories  have been
identified as ground-water pollutants in  the Baltimore  study area.


TOXICITY

Hazard Identification

     As described  earlier,  nitrates and  chlorinated solvents  are
the pollutants  covered by  this paper.    Adverse  effects  of  each
are discussed  below,  emphasizing human health effects.

     Nitrate  is a highly  soluble and mobile compound with a half-
life  in  ground water of  around  one and one-half  years.  It  is
commonly  found in high concentrations in septic  effluent.   At  the
low concentrations generally found in ground  water  the most seri-
ous health  effect  associated with nitrates is methemoglobinemia,
a reversible  disorder in  which blood hemoglobin is  oxidized  to
methemoglogin which  is unable to transport oxygen to body  tissues.
Ground-water  contaminated by septic tanks rarely or never has ni-
trate, concentrations high enough to  cause  this  effect in healthy
adults, but  infants  are susceptible at much lower levels.   Nitrate
                                B-2

-------
 concentrations for less than 20 tng/L have caused the condition in
 infants, although  cases  are more often  seen  in association with
 concentrations greater than 50 mg/L.

     Methylene chloride has been  classified as  a potential human
 carcinogen byEPA1sCarcinogen  Assessment  Group  (GAG)   on  the
 basis of laboratory  animal  studies.   In addition,  IEMP toxicolo-
 gists have  reviewed studies  performed  by  EPA  and  others which
 indicate that  methylene  chloride  exposures  are associated with
 teratogenic effects, fat vacuolization  in the liver, and tempor-
 ary increases  in  the levels  of  carboxyhemoglogin  in  the blood.

     Trichloroethylene is also  classified as a human carcinogen
 by GAG.  It may also cause  fat  vacuolization and necrosis in the
 liver.
                                                 ••i
     Ecological effects from  septic tank leachate  are primarily
 associated with high loading rates of  nutrients  and  dissolved
 organic carbon.  Dilution of septic tank leachate is sufficiently
 high that direct toxic effects are probably negligible; the major
 effect on aquatic  systems is  increased  potential for eutrophica-
 tion.

 Dose-Response Assessment

     Exhibit A  contains  information on the dose-response
 functions for  the  pollutants  covered  in this  issue  paper.  The
 potency estimates   for  carcinogens are upper  bound  estimates de-
 rived by  EPA's Carcinogen  Assessment  Group  (GAG).   Thresholds
 and potency estimates  for  other  effects  from methylene chloride
 exposures were derived by IEMP  and  represent  median values.  The
 no observed effects level (NOEL) reported for nitrate was identi-
 fied by the National Research Council.

     On the basis  of the  above hazard  assessment  discussion the
primary human health hazards  from  septic tank  contamination  of
ground-water in the study area are:

     o  cancer from ingestion of trichloroethylene,  and/or
        methylene  chloride,  and

     o  acute methemoglobinemia  in infants from  nitrates.
                               B-3

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                            Exihibit A

                   Dose-Response Functions  for
                      Septic Tank Pollutants
Contaminant
Nitrate
Methylene
chloride


TCE (Trichloro-
ethylene)
Effect
Methemeglobinemia
Cancer
Teratognicity
Liver (fatty vacuol-
ization)
Cancer
Threshold
(tng/kg day
NOEL = 10 tng/1
0
0.186
0.186
0
Potency^ /

6.3x10-4
1 .65x10-3
2.28x10-3
1 .9x10-2
Source
NRC
GAG
IEMD*
IEMD*
CAG
  1 .  Potency unit for Methylene chloride and TGE is (mg/kg day)"
      peer reviewed potency is not available for nitrate,  thus  the
      National Research Council  NOEL will be used to qualitatively
      assess nitrate risks.
EXPOSURE

     In this section we examine the potential for exposure to the
previously discussed contaminants  in  terms  of  the sources, path-
ways, ambient contaminant levels, and exposed populations.

Sources

     Septic tanks  are  the most  common alternative  to  municipal
sewers as a means of disposing domestic wastes.  In the Baltimore
study area they are used in both Baltimore and Anne Arundel coun-
ties.  Septic tanks  are  not used  in  Baltimore City, so  the ba-
lance of  this  section will  focus  only on  their use in  the two
counties of interest.  The map in Exhibit B indicates those areas
in these  conties which are most  vulnerable  to  septic tank conta-
mination.

     Baltimore County

     According to 1980 census  data approximately 11.7 percent of
the households in Baltimore  County use septic tank systems.  The
majority of these are located in the northern part of the county.
                               B-4

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                                                   Exhibit  B

                                             Map of Baltimore  and
                                             Anne Arundel  Counties
                                                  Phoenix-Nike-Missile
                                                  Site
                                                           Greenspring-N
                                                           Missile Site
                                                           Geologic Fall
                      «I
+/ Areas  in which septic 5£
  tanks  are the most
  common method for
  sewage disposal
                                                               Mayo
                                                               Peninsul

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                            EXHIBIT  C
          Factors  Affecting Contaminant Fate and Transport
   Factor
       Role in Fate and Transport of
       Contaminants from Septic Tanks
Unsaturated  Zone
Depth
Affects transport-time of constituents;, from
tank field ,to drinking water source-; thus
affecting amount of hydrolysis or denitrifi-
cation in unsaturated zone.         >
Soil Permeability
Low permeabilities result in reduced trans-
port time, high permeabilities cause; pooling
of effluent at soil surface, both high and
low decrease efficiency of effluent  treatment.
Fraction of Orga-
nic Carbon and
Cation Exchange
Capacity
 Important determinants of contaminant mobil-
 ity; chlorinated organics adsorbe on soils
 high in organic carbon, increasing transport
.time.  Neither factor has an appreciable
 effect on nitrate mobility.	,
Subsurface
Lithology
        **•
Non-productive aquifers and aquitards can
protect underlying sources of ground-water
by significantly slowing or preventing conta-
minant transport,  -i'lmportant factor in several
regions of Bait, study area.	'
Ground-water
Velocity and
Direction
High velocity promotes contaminant dilution
and dispersion, decreases time available for
contaminant decay.  Low velocity decreases
dilution but increases amount .of contaminant
decay.  Upgradient wells are unlikely to be
containinantd , downgradient well are most
likely to be contaminated.    ,. ,./	-
Septic Tank
Density
High and medium densities result in large  in-
puts' of contaminants to the subsurface,  in-
crease potential for well contamination.
Distance From Sep-
tic System to
Drinking Water
Well
Greater distances increase time for contami-
nant decay and area for effluent treatment
and contaminant assimilation.

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                            EXHIBIT - D
           Typical Hydrogeologic Conditions in Regions
          Using Septic Tanks in the Baltimore Study Area
Characteristic
                     County
                       Baltimore
Depth to Ground-
Water (feet)

Permeability
Fraction of
Organic Carbon

Cation Exchange
Capacity (meq)

Expected Ground-
Water Velocity
(ft/yr)

Lithology
  0-10 (coastal plain)
15 - > 100 (piedmont)

 very low (coastal
           plain)
 low to high (piedmont

          NA
          NA
          NA
                         Shallow unconsolidat-
                         ed sands, gravel, and
                         silt (Teritary & Qua-
                         tenary Sediments),
                         underlain by Upper
                         Cretaceous.clays and
                         coarse sands and Pata-
                         psco sands, gravel and
                         clay containing high
                         concentrations of dis-
                         solved minerals
                 Coastal Plain - Unconso-
                 iidated sands, gravel
                 and clay (Pleistocene
                 and Recent Age),  under-
                 lain by Anne Arundel
                 clay and unconsolidated
                 Patuxent formation.
                 Piedmont - Crystalline
                 rock formations includ-
                 ing well weathered Coc-~
                 keysville marble; frac-
                 tured Wissahickon schist
                 and phyllite; highly
                 jointed Peters Creek ,;
                 quartzite; and some low
                 permeability gabbro,
                 serpentine, granite, and
                 pyroxenite.

NA - .Information not available.     ;
J_/ Anne Arundel County information characteristic of Mayo penin-
   sula area, which is considered  to be the most vunerable are in
   the county.
2/ Estimate based on aquifer type.  Obtained in personal communi-
   cation with Geraghty and Miller, Inc., Annapolis, Md, January
   23, 1975.
                             Anne Arundel^ /
                                            0-2 (wet months)
                                            2-9 (dry months)

                                             Very low to low
                                                   NA
                                                   NA
                                                 1  - 1027

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                            EXHIBIT  E

        Summary of Ground-Water Pathway Characteristics in
               Baltimore and Anne Arundel Counties
Baltimore County

1 .  Coastal Plain (Southeast region of county along Chesapeake
    -local ground-water  obtained  from  unconsolidated  sands,  gra-
     vels, and clays with  very  shallow,  fluctuating,  water table
     (0 - 10 feet)

    -low soil peraeabilities cause  ponding  and  surface contamina-
     tion, reduce  ability  of soil to adequately  treat  effluent

    -high density  septic tank  population,  most tanks  installed
     prior to current  county  regs . requiring that  drinking water
     wells be placed no  closer  than  150  feet downgradient  or 100
     feet upgradient from  any septic system, thus  there  is close
     proximity of wells and tanks.

2.  Piedmont (Area north and west of geologic fall  line,  over 80
    percent of county)

    -ground-water flow primarily in fractured bedrock and solution
     cavities, some flow in highly  weathered bedrock.  These crys-
     talline formations  are not generally productive  sources  of
     ground -water.

    -widely varying soil permeabilities

    -ground-water depths  generally  greater  than-  30  feet,  some
     isolated locations of shallower ground-watr used as  drinking
     water source ,

    -in low permeability areas  tanks  have  been placed up to  12
     feet below ground ito  avoid surface  contamination.  This has
     led to a shallow  buffer  zone between tanks and ground-water
     and resulted in local ground-water contamination in isolated
     cases .

Anne Arundel County

    -located entirely  in coastal  plain,   subsurface  made up  of
     unconsolidated sediments overlaying   clay  and coarse sands

    -eastern region  of county  most  vulnerable, ground-water  in
     this area obtained  from  very  shallow Aquia  sand  sediments
     (water table 0-10 feet)

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EXHIBIT  E  (con11)
    -soils j;im vulnerable areas have .very low permeability
    -septic tanks in area oftn modified to avoid surface contami-
     nation by piping effluent directly  into local ground-water.
     This has  resulted  in  vseripus  ground-water  contamination
     problems in general area.   -*•"-•""
                        '•*.."
    -slow ground-water flows  in  eastern  regions do not allow for
     much contaminant dilution
           i,. " -^

    -most eastern communities were  developed before county ordi-
    nances requiring the placement  of  shallow wells, at least 100
    feet from a  septic tank,  deep wells  75 feet from tank.  Thus
    wells and  tanks  are  in  close proximity  in these  areas.

   -balance,ftof county not as  vulnerable *due to extensive sewering,
    better soil  permeabilities,  less  "tank  density,  and  more
    common ii&e of deeper Patapsco formation as source of drinking
    water.  r                       ?

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                          EXHIBIT  F
     Identified Constituents and Concentration Levels in
     Drinking Water Wells Contaminated by Septic Tank Use
                  (all concentrations mg/1)
Contaminant
Nitrate (as N)
Ave . cone
Cone, range
Methylene
Chloride
TCE
Cone, range
MCL
10


Baltimore County
Not identified as a
contaminant
Not identified as a
contaminant
.006 - .047t
Anne Arundel County
14.0*
10.0 - 23.0
Not identified
as a contaminant
Not identified
as a contaminant
* Nitrate levels for Anne Arundel county are representative of
  Mayo peninsula area only.  Source of data:  Anne Arundel
  County Health Dept. Mayo Peninsula Water and Sewerage Survey,
  1978.
t TCE concentrations pertain to wells near the Phoenix-Nike and
  Greenspring-Nike missel bases.  Elsewhere, no TCE has been
  detected in limited sampling of ground water.

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Some communities located on  the  Chesa'peake Bay to the  southeast
also use septic tanks.

     Septic tank density  in  the county  is quite variable.   The
southeast region was  originally populated by  summer homes  and
cottages which have now become year-round homes.   Density in this
area is  relatively  high because  it was  developed  prior to  the
development of current sewage disposal ordinances.  Lot  sizes in
this area can be as small as  1/4 acre,  each with their own septic
tank.  In the  northern sections development  is  less dense,  al-
though some pockets of  high  density can be found.  Much of this
region has  been developed under  county  ordinances   requiring  a
minimum lot size of four acres for septic tank use.

     Several of  the  past  serious  contamination  incidents  in
Baltimore County have been the result of  using large  septic tanks
as disposal  systems at  military  installations.   These  systems
were properly designed  to dispose  of  human wastes  from  a  large
number of people.   However,  they  were also  used to dispose of
many other  types  of waste  including chlorinated solvents  which
eventually contaminated  ground-water.  Although  few  other  inci-
dents of this type  have  been discovered,  the  chemical contamina-
tion of  ground-water  from septic  tank use by commercial  units
such as  shopping  centers and gasoline stations could be a wide-
spread problem. */_

     Anne Arundel County

     1980 census data indicate that approximately 32.2 percent of
the households  in  Anne Arundel county use septic systems.  Al-
though septic tanks are used to some degree in all regions of the
county, the large majority of the areas most vulnerable to ground-
water contamination because of poor hydrogeology and/or high popu^-
lation density are  now served by municipal sewer systems.    How-
ever, in some highly vulnerable  areas  located south  of Annapolis
along the western shore of the Bay, septic tanks are still in use
in high  densities,  and ground-water contamination has  resulted.

     The most highly  studied region in  this  vulnerable area is
the Mayo Peninsula.  Septic  tank density in this area is extreme-
ly high,  with about 230 tanks/sq. mile.    This very  high density
is not typical  of the  majority  of  the  county.  In the Mayo peni-
nsula area  drinking  water  is  obtained   from  privately  owned
shallow wells which are particularly  vulnerable  to   contanimina-
tion.  Water  obtained  from  deeper  wells  in  these  coastal areas
generally contains  high  concentrations   of   iron  and  sulphur,
I/ Personal  communication,  Mr.  Thomas Ernst,  Supervisor,  Water
   and Sewerage  Programs,  Bait.  Co.  Dept. of ^Health,  with  Paul
   Lewandowski,  Sobotka & Co.,  Inc.             •   .


                                B-5  .

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making it  an  unsuitable  option as a drinking water  source.   Al-
though the May  Peninsula is an extreme  case,  other areas located
in the  coastal  region may also be  particularly  vulnerable.   Un-
like Baltimore  County,  Anne Arundel  County has  not  experienced
chemical contamination due  to  commercial scale  septic  tank  use,
and it is not expected to be a major problem.^/

Pathways

     Because  septic  tanks  are -designed to release  contaminants
into the subsurface environment, any septic system can potential-
ly contaminate  ground-water.   The use  of this contaminated water
is a  source  of  drinking water  is  the  most  likely pathway  for
exposure to pollutants  resulting from  the  use of  septic tanks,
and thus ingestion  via drinking  water  is the  exposure pathway of
interest.  Although  septic  tank  use can result  in  surface water
contamination,  we do  not regard this as likely  to be  a signifi-
cant exposure pathway because:  (1) local water suppliers monitor
for nitrate and maintain concentrations under the  no observable
effects level  (NOEL) to comply  with  Safe  Drinking   Water  Act
requirements, (2) solvents entering surface water via septic tank
leachate are  initially  present  in dilute  concentrations,  and
quickly volatilize,  and  (3)   treatment  of  surface  water  will
remove some of  the  contaminants if  they are present.  Therefore,
we do  not  consider  this pathway to be  an  important  source of
exposure.

     There are  several  factors  which  play  important  roles in
determining the  extent  to  which  a  drinking  water  well  will be
contaminated  by effluent from  septic tank systems.  These  include
contaminant release  rates,   soil and   hydrogeologic  conditions,
location factors, and system design.  Although releases will  vary
depending on  the  number  of individuals using the system and the
composition of  wastes disposed,  previous studies have  found  that
a single tank serving an average 4-person household will release
approximately 280  m^/yr  of  effluent into  the  unsaturated zone.
This results  in a typical system  releasing  over 5 kg/yr of nitr-
ate.  Chlorinated solvents  are not  as  easily typified; however,
it is clear that  total releases  of  the above  constituents can be
substantial in  areas  of  thigh,  or  even medium,  septic  tank  use.

     Soil  and hydrogeologic conditions  largely determine  the,fate
and transport of the released pollutants.  Contamination incidents
in both  counties indicate  that  problems are of ten  very site-
specific, and that predicting  fate  and transport on the basis of
local hydrogeologic conditions  is  rarely a simple  matter.  How-
ever,  there are a number of important  characteristics  for which
2/ Personal communication,  Singh  Dhillon,  Anne Arudel  Co.  Dept.
   of Health,  with Paul Lewandowski, Sobotka & Co., Inc.
                               B-6

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general statements concerning  their  Impact  can  be made.   These
include:

     o  unsaturated zone depth,

     o  soil characteristics,  particularly permeability,  fraction
        of organic carbon and  the cation exchange capacity of  the
        soil,

     o  lithology of  the sub-surface,  including  the presence of
        overlying aquifers and aquitards,  and

     o  local ground-water flow rates and direction.

In addition, locational  factors such  as  septic  tank  densities,
and distances from septic  systems  to drinking water  wells affect
the level of well contamination.

     Exhibit C summarizes  the  role of each  of  the above factors
in contaminant fate and  transport, and  Exhibit  D contains infor-
mation concerning typical hydrogeologic conditions in the regions
of Baltimore and Anne Arundel  counties where septic  systems  are
commonly used.

     In these  exhibits   we briefly  present  the  most  important
factors pertaining to ground-water contamination  as  the pathway
for human exposures.  In Exhibit E we summarize the potential for
exposure in Baltimore and Anne Arundel counties via this pathway.

Ambient Concentrations

     The movement of  contaminants  based on the factors discussed
in the previous  section can potentially  result  in contamination
of drinking  water wells  at  concentrations  above drinking water
standards.  These concentrations can result in human health risks
that could be considered significant.

     Exposures to  nitrate and   methylene  choride  from  drinking
ground-water contaminated  by  septic tank  effluent have  recently
been modeled  in  a  study  conducted by EPA's  Office of Policy
Analysis that compared health risks from six different sources of
ground-water contamination.   Preliminary results indicated  that
in high  and medium septic tank  density areas methylene  chloride
concentrations in wells  can reach  levels resulting in upper bound
cancer  risks on the order  of 10"^.  This  contaminant moves rapid-
ly through  the unsaturated  zone,  thus  both shallow  and deeper
wells can be contaminatd.  Because of this rapid  movement and its
moderate carcinogenic potency,  methylene  chloride was  found to be
a more  important contributor to  risk than nitrate. This  was  par-
ticularly true  in areas of  rapid  ground-water  flow,  and would
likely also  be  the case in  situations where  wells were  located
short distances from the septic  tank field.  As mentioned earlier,


                                B-7

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methylene chloride is  considered  a carcinogen by EPA and  it was
modeled as such.

     Although nitrate exposures can have serioud effects, nitrate
concentration3 in septic effluent are generally quite low (around
wO mg/L), resulting in/relatively small loading rates to* the sub-
surface, particularly an relation  to the low toxicological potency
of nitrate.  In  addition,  nitrate degradation  in groun'd-water is
significant, with a half-life  of 1.5 years.  The  combination of
these factors results -an  insignificant  exposures to nitrate from
septic effluent  in most  cases.  However,  high- revels  cSf nitrate
associated with  septic tnk use  have  been  found in  Ann Arundel
County.                                       ,

   .- ^Below we  present  data on   concentrations  6f  contaminants
found in drinking water  wells  which  can potentially be  linked to
septic tank  use in each  county.  These  data  •are*wsummarized in
Exhibit F,  which also  contains current drinking  water  standards
for comparison  purposes.   We  also discuss  some  significant past
contamination incidents  to illustrate  the potential   level* of
exposure in the  study area.                                f! ;5H>

     Baltimore County                  ~   - •»         ;      ?

     Baltimore County has  experienced  several  major ground-water
contamination incidents  directly  linked  to  septic tank  useage
which have  resulted  in  drinking  water  wells   contaminated with
trichloroethylene.   The  most   important and  well-documented  of
these occured  at the  Phoenix-Nike missile  location outside of
Jacksonville^  At this  site contamination  of  ground-water appa-
rently resulted  from the  disposal of TCE  in the septic  tank used
to dispose  of the  base's sewage.  Reasons  for  this disposal are
not clear;  however  wells  in-  the area  are  considered  unfit for
drinking water  use  because 6f TCE levels  as high as 47 ug/L at
site boundaries  and  8.6' ug/L  in  private wells  180 meters north
of the site,  which  is the predominant  direction  of ground-water
flow.  Although  the site was   closed in 1966,  this contamination
was not discbvered until  the  late 1970' s.   Eight  to tfn private
wells have been  contaminated.  In a  similar incident, -the septic
system servicing .the  now  closed  Greenspring-Nike  missiie base,
locatejl near  the Chestnut  Ridge  subdivision  10  milWs west of
Cockeysville, has also been implicated  as a source ofi/^TCE co'nta-
mination.  In this  case,  contaminant  levels  in  drinking water
wells on the base were as high as 15>
-------
     Nitrate  contamination from septic tanks has not been  identi-
fied as  a major problem  in the county,  including the vulnerable
coastal  plain area.  In the  northern .portions  of the county  ni-
trate concentrations  higher than^the drinking water standard have
been found  in ground-water.  However, this is most likely  associ-
ated withv naturally occurring  soils.f,and  agricultural uses of  ni-
t-y-af-o   *i                ^'"' •     '•••-  -'*'•
ULciUC.                   /-  •. •   .^  .  , .,
     •>   .             , .•••   ..,3j ;    \&. . •$   •'--.              .
     Anne, Arundel: County   *^.:x .x    .-.,-,..'•     .
  •.*-   '     «..  '••       ':'        '• •*'•'' -'; *;*£•"•*  -                >
     Past surveys, of  ground-water^users in the  area indicate  that
ground-water"''pollution  has been  a  significant  problem.   A large
survey conducted, approximately 15 years ago found that  66 spercent
of the  drinking water  wells  infethe county  exceeded  the  Maximum
Contaminant Levelis ,f(MCLs), established  .under  the  Safe Drinking
Water Act, for at.-least  one pollutant.^/  The importance of septic
tank use as a s.ojUyceje  of .this  contamination was  not explored;  hpw-
ever^~|i*fe is likely- to  be  less  »of  a contributing factor*now Ithan
it was* then,  because  of the continued sewering  of many  vulnerable
areas'.i«*£:""> • £  •*.-:•:;?'  '.%*••.,*.£•                      '
   "^'"' ''. . ' 'A .   . *?*£ '     .:;.'•'•'          ,    .
     ••',ft'f • •••••-    '•••*•'•<  • . ••                 . •                           -
    ijA  1978 survey of the  Mayo peninsula area found that  over 35
percent  of  the households in  the* area  had  experienced problems,
with their  septic tank  operations.^/  A drinking water sampling
study undertaken concurrently found~that about  ten percent of the
drinking water wells  in  the peninsula were contaminated with fecal
coliform bacteria (i.e.,  bacteria  were  present)  and  five  percent
of the .wells-were contaminated with nitrate in  concentrations in
excess ofv the TO mg/L MCL.  ^As  Exhibit F  illustrates,  nitrate con-
centrations ranged from 10 to  23  mg/L,  with an  average of around
14 mg/L.   Because Mayo county  is a particularly vulnerable area,
these frequencies  and  contaminant  levels are  likely  to  be  the
highest  in  
-------
Anne Arundel County

     Although 32 percent of the households  in Anne Arundel  county
use septic tanks,  and  26.7 percent  obtain  their drinking  water
from private wells, the majority of these individuals  are unlike-
ly to be exposed  to  contamination  caused  by  septic tank  use.
Those most  likely  to be  exposed are  individuals living  in the
eastern portions of the  county south of Annapolis, particularly
people living in the Mayo peninsula  area.  The  1978 study  of the
peninsula identified 1925 households  in  this area; with a total
population of 5,922  according  to the  1980  census.   This  repre-
sents approximately 1.5  percent  of  the  total population  of  the
county.

     The above  exposure  assessment  indicates that  contamination
of ground-water  due  to  the  use of  septic   systems  can and  has
occured in the  Baltimore study area.  Human  exposures  to?septic
tank pollutants via the ingestion of contaminated ground-water is
possible at  significant  concentration  levels  in some  specific
areas, and most problems will  be very localized.  The  next  sec-
tion discusses the human  health risks associated with these  poten-
tial exposures.


RISK CHARACTERIZATION

     Human health  risks  from  the  use of  septic  tanks   in  the
Baltimore study area are primarily  due  to  exposures to hazardous
concentrations of  nitrate, trichloroethylene (TCE), and possibly
methylene chloride.  Because the use of septic tanks in Baltimore
and Anne Arundel  counties is  local  in  nature,  estimated risks
pertain only to those  areas  where septic tanks  are used.   Also,
because there are  no  data  available  on  chemical pollutants  in
many privately-owned wells, it is  difficult  to  determine whether
there are substantial chronic human health risks from septic tank
releases over much of the area.

     Below we specifically discuss  the risks from  each of these
pollutants.  We  have  divided  the  chemical  pollutants  into two
categories, those whose  major  effect is  cancer  (trichloroethylen
and methylene chloride), ' and those  considered to be non-carcino-
genic (nitrates)   because  of  important  differences  in  dose-
response assumptions used in our risk assessments.

Non-Carcinogens;  Nitrate

     Because we  currently  do  not  have a dose-response function
for nitrate  which  has been  peer-reviewed,   we  can not estimate
individual risks or population  risks  for this pollutant.  However,
in Anne Arundel County concentration levels of nitrate as high as
23.0 mg/L  (as nitrogen)  have  been  found.  These levels are more


                           B-10

-------
than two  times  greater  than  the  no ^observed  effect level  for
nitrate of  10  mg/L nitrate-nitrogen.   Because  of  this,  infants
exposed to drinking water in the Mayo peninsula area  are  at  some
risk of  methemoglobinemia.   According  to  Singh  Dhillon  of  the
Anne Arundel Dept.  of Health,  the  Mayo Peninsula  community  has
been warned several times that  children should not use well water
for drinking, so there may be little exposure.  Adults are prob-
ably not at risk.

     In Baltimore County no nitrate contamination has been relat-
ed to septic tanks, therefore added  risk of  methemoglobinemia is
likely to be very low in this area.

Carcinogens;  TCE and Methylene Chloride
            t. j
     Trichloroethylene is the only carcinogen known to be present
due to septic tank releases in the study area.Risks from trich-
loroethylene exposures can be calculated using CAG potency values
derived based on  modified  multistage model  for carcinogenicity.
This model  assumes  a  linear dose-response  curve at low doses and
no biologic threshold.  The potency estimates are the upper bound
95% confidence limits, so the resulting risk  estimates are conser-
vative (i.e., tend to overestimate risk).

     There  is currently no exposure at the sites where TCE conta-
mination is known to exist.  However, if we  assume  that TCE con-
tamination  exists  undetected  at other  sites, and  is present at
the same concentrations as those detected around the  Nike missile
sites, we  can estimate  ri~sks  at  other potential  contamination
sites by using the following assumptions:

     o average adult  consumption of drinking water is 2 liters/
       day,

     o average adult body weight is  70 kg, and

     o contaminant  concentrations  remain constant  over  an indi-
       viduals lifetime, which is assumed to be 70  years.

Using these  assumptions, individuals upper bound cancer  risks at
the TCE  concentrations  listed  in Exhibit D range from 3.2 x  10~»6
to 2.6 x  10~5.

     In Anne Arundel  County no  contamination  of drinking water
wells by  chlorinated  solvents via  septic  tanks has  been  identi-
fied.

     In  a study  of human health  risks  posed by  ..releases  from
different sources  of  ground water  contamination,  EPA's  prelimi-
nary results  indicated  upper  bound  cancer risks... from exposure  to
methylene chloride  range from about  10~4 to  10~*0 under different
                               B-ll

-------
hydrogeological and release scenarios.  If people  are  exposed to
methylene chloride from septic tank releases,  this  range  probably
brackets the risks in the Baltimore study  area.

     To summarize, contamination  of ground-water  due  to  septic
tank use is not a widespread problem in the Baltimore study area.
However, a  history of  contamination  incidents  shows  that  the
study area does contain some vulnerable areas  in  which  concentra-
tions of nitrates and trichloroethylene can reach levels  suffici-
ent to  pose human health  risks.   Future  studies  of this  issue
would need to focus on accurately identifying  these areas,  deter-
mining the  types  and  volumes  of releases, and detecting  concen-
trations of pollutants  in  drinking water  wells.  This would  be
particularly useful in determining the importance septic  tanks as
a source  of chlorinated solvent  contamination   of  ground-water.
Although few incidents of solvent contamination have been report-
ed in  the  study area,  several  local environmental  scientists
believed such contamination to be more widespread than previously
thought, particularly in Baltimore County.

     Because the  exposure pathway  of  interest is the drinking of
contaminated ground water,  any future studies  should also include
risk mitigation and prevention strategies as  the  process  of char-
acterizing the possible  extent  of septic  tank-related  problems.
Drinking water contamination  problems  due to septic  tanks have
traditonally been solved by the extension  of  municipal water and
sewer services into  vulnerable  areas.  However,  this  is  often a
very costly  option which  encourages  increased  development  and
consequently can  bring  new human health  risk factors  into these
areas.  Because the population at risk from septic tank pollution
appears to  be  fairly  low  in the study area, additional  focus for
future work should probably be  on the  development  of  relatively
inexpensive and efficient means  of  managing contamination problems
at the source level (e.g., limits on use of solvents for cleaning
tanks) as well as the continued development  of  local regulations
pertaining to septic tank siting.


COMMENTARY

     This issue  is  directly related  to two  other  issues  in the
Baltimore study:

     o risks  from sewage  treatment  (the primary  alternative to
       septic tanks for treating  domestic wastewater), including
       sludge disposal, and

     o risks  from residential  and  agricultural  application of
       fertilizers and pesticides  (these  sources also are  in the
       immediate proximity of residential  wells, and can release
                               B-12

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       nitrates and chlorinated organics).

     Although septic tanks are recognized as potential sources of
pollution in several areas,  and have been  studied for several pol-
lutants in seveal areas, there is a moderate-to-high level of un-
certainty in most  of  the risk assessment aspects  of  this issue.
In terms  of  hazard  assessment,   a  dose-response  function  for
nitrate is not readily available, and there is considerable uncer-
tainty in the dose-response functions and weight  of evidence for
carcinogenicity for TCE and methylene chloride.   And  in terms of
exposure assessment, routine monitoring of private wells does not
occur for even  "conventional"  pollutants  like nitrate,  much less
trace organics,  so it is very hard to  estimate  exposure levels.
For these reasons,  and because of the  time  lag  that  occurs bet-
ween release of pollutants to ground water and exposure to pollu-
tants in  drinking  water wells,  it is  relatively  difficult to
characterize the risks  from septic tank releases.
                                B-13

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APPENDIX C
  EPILOG

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                        APPENDIX C.  EPILOG

     In this  "concluding  unscientific  postscript"  we  describe
some of the ways in which  we think the Baltimore  IEMP has already
contributed to  improved environmental management  for  the  study
area.  These  improvements  include tangible accomplishments  with
an immediate  consequence  for improved  public health  (e.g.,  the
change which reduced the standard for the  lead used in  solder and
flux in residential plumbing).   They also include  less  tangible
events which may prove to be more important  in the  long run for
environmental management;  our  use of  an  explicitly risk-driven
process to help  set  priorities among the  environmental  problems
is an example.  This  is a new, and we hope permanent, way of  doing
business.   Here, then, are  our  concluding thoughts on  Phase  I.

The Baltimore IEMP Established a Prototype for Locally-Managed
Setting of Priorities

     o  In a  first for IEMP projects EPA delegated authority to
        the local-level to  manage  the  Baltimore  IEMP  with  the
        result of greater  activity and  commitment  on the part of
        local officials.   This includes project direction, polic-
        ies budget allocation,  priority  setting,   and  technical
        work EPA functions in a staff capacity.

     o  This  is  the  first  time different governmental  agencies
        (state, local.  Federal)  in the study area have had a forum
        in which to discuss a wide range  of  environmental issues
        and to set priorities across them using a common language
        (risk) and tools.    This has provided an opportunity for
        faster action  in  identifying and  acting  on  potential
        environmental problems  (e.g.  the  lead solder  issue dis-
        cussed below).

     o  The IEMP provided  an opportunity to  learn  about and use
        various analytic tools  for  defining  environmental  prob-
        lems and  setting  priorities.   Project  staff  from  EPA:

           assembled various  data bases  at   the  request of  the
           Technical Advisory Committee to help identify a set of
           32 potential pollution problems.

        -  helped develop methodologies to establish criteria to
           rank these 32 problems and narrow  this set for further
           (Phase II) study.

        -  conducted a day-long seminar for the general public to
           explain the  methodologies  and results   of   Phase  I.

     o  We hope that this  new way of doing  business will become
        a permanent feature of environmental  management  in
        Baltimore.
                               C-l

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        -  We cannot  be  certain that the institutional  arrange-
           ments fostered  will  become  a  permanent part of  the
           Baltimore area's environmental  infrastructure.  We can,
           however, take  encouragement  from  the  involvement  of
           representatives from the  key jurisdictions and  their
           various environmental organizations and  approximately
           60 workgroup  members,  as  indicative  of  a potential
           group of  apostles.   Their  investment  also  makes  us
           optimistic that the  local and  state governments  will
           implement our  Phase  II  findings  or  reflect  them  in
           future environmental management decisions.

The IEMP provided direct advice and guidance  to Maryland's  air
toxic program.

     o  The  IEMP  provided a  conceptual basis (risk  assessment)
        for the proposed state program and  guidance  on how  it
        works in practice.

        -  EPA staff  assisted  the State in development  of  their
           emissions inventory and provided practical  assistance
           in how  risk  assessment  could be  used  to determine
           acceptable emissions/exposure levels.

        -  EPA staff conducted preliminary monitoring over  a six
           month period and did the initial  risk  assessment work.

     o  The IEMP focused the State's attention on  unusual sources
        of toxic emissions and additional  problems.

        -  We identified POTWs not  only as  a source   of  toxic
           emissions but  also  as  a  classic  case  of  intermedia
           transfer of pollutants.

     o  The  IEMP  provided direct  technical   assistance to  the
        State.

        -  A member of  the IEMP staff was a member of the  advisory
           panel for the State's program.

        -  EPA helped  the state  organize a  one-day seminar for
           citizens and industry.   It dealt with  the role of risk
           assessment in the proposed program.

     o  The IEMP paved the way for ORD's Total Exposure Assessment
        Methodology (TEAM) project in Baltimore.

        -  We provided  the introduction  to  local  officials  and
           are influencing the study design  so its results  will
           be available for use in local policy decisions regard-
           ing outdoor versus indoor air pollution.
                               C-2

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The IEMP has  influenced a change  in  local codes on the use of
lead solder in residential plumbing.

     o  The IEMP  convened a workgroup  to  examine the problem of
        metals across  environmental media.   This fresh examina-
        tion  of human  exposure  to lead  versus other metals showed
        that  this  "well  understood and  controlled"  pollutant
        remains a major threat  to human health.

        -  A  simple  analysis  of  hospital records  (which showed
           150 hospitalizations per  year of children  in Baltimore
           City for  lead  chelation  therapy)  indicated  that lead
           remains   one  of  the   primary  environmentally-caused
           threats to  human health.   Further,  our  analysis  of
           potential risks from lead in drinking water in  compari-
         -  son with  other risks showed that lead in drinking  water
           can cause significant  risks.  This occurs  primarily  in
           areas with  corrosive water and in buildings with newly-
           soldered  plumbing.
                                                '-r
           The local plumbing  board has moved voluntarily to re-
           duce from 2% to  0.2% the amount of lead in solder and
           flux used in Maryland's plumbing.

The I£MP is developing a methodology to help  set  priorities  for
action  among  the wide  variety  of  leaking underground  storage tank
situations.

     o  The  work may  be applicable elsewhere—for  instance,  in
        Maryland's Ground-water Strategy—in helping set priori-
        ties  for a planned state-wide monitoring  program.

     o  This  approach  is  also  of major interest to  EPA's Office
        of Underground Storage Tanks for possible application  in
        other states and localities.

     o  EPA's Office  of  Research and  Development  is also  inte-
        rested in  determining   if  our  approach  could be used  to
        set priorities for determining  the location  and  frequency
        of their program to monitor the effects of acid precipita-
        tion  on ground-water.

The IEMP identified  and convened  a group of  city* county  and state
officials who regulate activities affecting  Baltimore Harbor.

     o  This  coalition is one  of  the first  successful  efforts  to
        bring together representative  of  key  agencies  and  to
        work  cooperatively on  the Harbor.

The IEMP identified  indoor air pollution as  an  issue  for  study.

     o  Partly as a  result of  our efforts,  Maryland  will  seek EPA
        assistance (from  the  Office of Radiation)  to  conduct  a
       , state-wide survey   for radon   during  winter


* U.S. GOVERNMENT PRINTING OFFICE: 1987-716-002/60604       C"3

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