\"
             UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

                         WASHINGTON, D.C. 2d460
                                           EPA-SAB-EEC-90-010
                                                           OFFICE OF
                                                        THE ADMINISTRATOR
 March 27, 1990

 Honorable William K. Reilly
 Administrator
 U.S. Environmental Protection Agency
 401 M Street, s.W.
 Washington, D.C. 20460

 Dear Mr* Reilly:

      The Science  Advisory Board has completed  its review of the
 Office  of  Research  and  Development's   (QRD)  Municipal  Waste
 Combustion Ash Solidification/Stabilization (S/S) research program.
 It was based  on briefing materials and discussions with staff  in
 a  review  meeting  conducted on  September  18-19,  1989 by  the
 Municipal  Waste  Combustion  Ash  Subcommittee   (MWCAS)  of  the
 Environmental   Engineering   Committee   (EEC),   and  on  selected
 materials provided to the MWCAS in May and June, 1989,

    .  The issues reviewed by the Subcommittee were  (1) appropriate
 testing procedures  to be applied  to S/S  ash  products  and reuse
 products made  from S/S ash  to  determine  long-term environmental
 effects, and  (2)  methods of testing to  determine the bioavail-
 ability and toxicity of S/s ash products.

      The OSD  staff  are  to be complimented on their formation and
 effective  use  of  a  Technical  Advisory  Panel  (TAP),    The  TAP
 provided focused technical input on the best applications of GRD's
 limited funding,

      Highlights of our findings and recommendations for  long-term
 effects research  are as  follows.   The highly  variable array  of
 ashes fr
-------
     Bioavailability  and  toxicity  should be  examined  as  two
distinct and separate phenomena.  While limited in scope, bioassays
can be  used effectively  for  making relative comparisons  of the
toxicities of leachates  derived  from various  ashes and products,
Extensive bioassay testing will be required, and  no single bioassay
procedure can adequately  assess biological effects of residue reuse
or disposal alternatives.

     The Municipal Waste  Combustion Ash research program should be
reviewed for adequacy of funding.   This  program should emphasize
front-end  prevention at least  as much  as  back-end  treatment.
Additionally, the potential  risks associated with ash  disposal
should be compared with long-term risks associated with alternative
municipal solid waste disposal options.

     We appreciate the opportunity to provide  advice to the Office
of  Research  and  Development's  municipal  waste  combustion  ash
research program on this  important topic,  and  look forward to your
response.

                              Sincerely,
                              Raymond C. Loehr, Chairman
                              Executive Committee
                              Science Advisory Board
                              Richard A. Conway, Chairman
                              Environmental Engineering Committee
                              Science Advisory Board
                              Ben B. Evring, JEhairman
                              Municipal Wa^te Combustion Ash
                              Subcommittee
                              Science Advisory Board

-------
                U.S. Environmental       Washington, DC
                Protection Afl*ncy       EPA-SAB-ESC-90-010
         Report of the Municipal Waste
         Combustion Ash Subcommittee
          Review of the ORD Municipal
          Waste Combustion Ash Solidification/
          Stabilization Research Program
A SCIENCE ADVISORY BOARD REPORT                  March 1990

-------
                              EPA-S&B-EEC-9Q-01.Q
REPORT Of TIE MUNICIPAL WASTE COMBUSTION ASH SUBCOMMITTEE
        OF THE ENVIRONMENTAL ENGINEERING COMMITTEE
           REVIEW OF THE OFFICE OF RESEARCH AND
       DEVELOPMENT'S MUNICIPAL WASTE  COMBUSTION ASH
       SOLIDIFICATION/STABILIZATION RESEARCH PROGRAM
                        MARCH,  1990

-------
                             NOTICE

     This report has been written  as  a  part of the activities of
the Science  Advisory  Board,  a public  advisory group  providing
extramural scientific information and advice to the Administrator
and other officials of the  Environmental  Protection Agency.   The
Board is  structured  to provide a  balanced,  expert  assessment of
scientific matters related  to problems  facing the  Agency.   This
report has not  been  reviewed for  approval by  the  Agency,*  hence,
the comments of this  report  do not  necessarily represent the views
and policies  of the  Environmental Protection Agency  or  of other
Federal  agencies.    Any  mention   of  trade  names   or  commercial
products does not constitute endorsement  or recommendation for use.

-------
                             ABSTRACT

     The  Municipal  Waste  Combustion  Ash  Subcommittee  (MWCAS)
reviewed   the   Agency's    municipal    waste   combustion   ash
solidification/stabilization  (S/S) research program.   The issues
reviewed were (1) appropriate testing procedures to be applied to
S/S ash products and reuse products made  from  s/S ash to determine
long-term environmental  effects,  and  (2)  methods of  testing to
determine the bioavailability and toxicity of S/S ash products.

     The Subcommittee's findings and recommendations for long-term
effects  research  dealt  with  test  routines  and  leach  testing
research, focusing upon the properties  of  the leachate  and the
physical and chemical characteristics of  the solid matrix in order
to define  the breakdown and exposure  of surfaces  of  stabilized
products, the need  to  evaluate weathering,  and  for  some  reuse
alternatives, of dynamic abrasion  and erosion,  other findings and
recommendations dealt with the effect of  salts, microbial activity
and swelling of ash upon  the  long-term usefulness of  concrete
products, and the usefulness of deterministic models of transport
mechanisms to assess relative  effectiveness  of the various S/S
treatment processes.

     Highlights   of  the    findings   and  recommendations   for
bioavailability and toxicity dealt with examining bioavailability
and biotoxlcity as  two distinct  and  separate  phenomena,    the
effectiveness of bioassays  for making relative comparisons of the
toxicities of leachates  derived from various  ashes and products,
the need for extensive bioassay testing,  and  the  finding that no
single bioassay procedure can adequately  assess biological effects
of residue reuse or disposal alternatives.

Key Words:     Ash, Ash Research,  Municipal Waste Combustion Ash,
               Ash Solidification/Stabilization

-------
           MUNICIPAL WASTE COMBUSTION ASH SUBCOMMITTEE
               ENVIRONMENTAL ENGINEERING COMMITTEE
                              of the
                      SCIENCE  ADVISORY  BOARD

Chairperson

Or. Ben B. Ewing, Professor of  Environmental  Engineering, institute
for Environmental Studies, University of Illinois

Members and Consultants

Mr. Allen Cywin, Consultant, Savannah,  Georgia

Mr. George Green, Manager of Electric Operations Services, Public
Service company of Colorado, Denver,  Colorado

Dr. Rolf Hartung, Professor of Environmental Toxicology, School of
Public Health, University of Michigan,  Ann Arbor, Michigan

Dr. William  Haun,  Director of  Engineering, General  Mills,  Inc.
(Retired), Maple Grove, Minnesota

Dr. Ishwar P, Murarka, Program Manager for Land and Water Quality
Studies, Environmental Division, Electric Power Research Institute,
Palo Alto, California

Dr. Walter  M. Shaub,  Technical Director,   Coalition  on Resource
Recovery  and  the   Environment,  U.S.  Conference   of  Mayors,
Wash ington, DC

Dr. Thomas  T. Shen,  Senior Research  Scientist, New  Yorlc state
Department of Environmental Conservation, Albany, New York

Science Advisory Board Staff

Or. K.  Jack  Kooyoomjian,  Designated  Federal  Official,  Science
Advisory Board (A101F), U.S. Environmental Protection Agency,
Washington, DC 20460

Mrs. Marie Miller, Staff Secretary, Science Advisory Board

Dr. Donald G. Barnes, Director,  Science Advisory Board

-------
               TABLE OF CONTENTS




1. 0  EXECUTIVE SUMMARY.	 ,	........	1




2 . 0  INTRODUCTION	...»	............................ 2




3.0  LONG-TERM EFFECTS...........	...................... 3




4.0  BIQAVAILABILITY/BlGTOXieiTY	.7




5. 0  OTHER RELATED ISSUES	 10




APPENDIX A - THE CHARGE TO THE SUBCOMMITTEE.......	. . .	12




APPENDIX B - GLOSSARY OF TERMS AND ACRONYMS.	13




APPENDIX C - INITIAL REVIEW DOCUMENTS	 14




APPENDIX D - RESOURCE MATERIAL	,	.15

-------
i-0  EXECUTIVE SUMMARY

     The Municipal Waste Combustion Ash Subcommittee (MWCAS) of the
Science Advisory Board's  (SAB) Environmental Engineering Committee
(EEC)  reviewed  the  Agency's  municipal  waste  combustion  ash
solidification/stabilization  (S/S) research program.   The issues
reviewed were (l) appropriate testing procedures to be applied to
S/S ash products and reuse products made  from S/S ash to determine
long-term environmental  effects,  and  (2)  methods of  testing to
determine the bioavailability and  biotoxicity of S/S ash products.

     Highlights of the findings and recommendations for long-term
effects research are as follows:

     a. The  highly variable array of ashes from  many combustion
facilities dictates that  test routines developed must apply to the
behavior of various products of different ashes.

     b. The research program should address both the properties of
the leachate and the physical and chemical characteristics of the
solid  matrix in order to define the  breakdown  and  exposure of
surfaces of stabilized products.

     c. There  is a  need to  continually evaluate the  effect of
weathering, and possible dynamic abrasion and erosion, the effect
of salts, microbial  activity and  swelling of  ash, for evaluation
of the long-term effect of use  of S/S  products for some purposes
such as road base or building materials.

     d. Deterministic models of  transport mechanisms may be useful
to assess  relative  effectiveness of the various S/S  treatment
processes.

     In discussing bioavailability and toxicity,  the Subcommittee
recommendations the followingt

     e. Bioavailability  and toxicity should  be  examined  as two
distinct and separate phenomena.

     f. While limited in scope,  bioassays can be used effectively
for  making  relative comparisons  of  the   toxicities  of leachates
derived from various ashes and products,

     g. Extensive bioassay testing will be required, and no single
bioassay procedure can adequately  assess biological  effects of
residue reuse or disposal alternatives.

     The  Subcommittee  is  concerned that  the  Municipal  Waste
Combustion  Ash  research  program is inadeguately  funded.   The
Municipal Waste Combustion Ash program should emphasize front-end
prevention at least as much  as back-end treatment.  Additionally,

-------
the potential risks associated with ash disposal should be compared
with long-term risks  associated  with alternative municipal solid
waste disposal options.

     The Office of Research and Development (QRD) has established
and used a Technical Advisory Panel  (TAP) to guide its management
of the S/S program to effectively use the very limited resources
of money and manpower.


2.0  INTRODUCTION

     At the request of the Office of  Solid Waste  (OSW), the Office
of Research and Development (ORD)  has instituted a research program
on municipal  solid waste  (MSW)  disposal and  particularly  on the
handling,  disposal and  possible reuse  of ash  produced  by the
incineration  of  MSW.   While  this is  a continuing  program,  the
current research is focused on the solidification and stabilization
of municipal waste combustion ash (S/s)«  Phase I of the program,
which is already in progress, is a demonstration of the technical
feasibility of various methods of S/S and characterization of the
short-term environmental behavior of the products of S/S.

     The Science Advisory Board was aslced to review the Municipal
Waste  Combustion Ash  (MWCA)  research  program and  assigned the
review to the Environmental Engineering Committee (EEC).  The EEC
has established a  MWCA Subcommittee,  members  of which are listed
in this report.

     The Subcommittee  (MWCAS)has been charged with (a) a continuing
review of  the ORD MWCA research program, and (b) more immediately,
consideration  of   two  issues   related  to   the   current  S/S
demonstration.  These  two issues, considered at the initial meeting
of the Subcommittee,  were  (1) the appropriate testing procedures
to be applied to the S/S  ash products and reuse products made from
the S/S ash to determine the long-term environmental effects, and
(2) appropriate methods of testing to determine the bioavailability
and "biotoxicity" of S/S ash products.

     The issues to  be  considered at the initial meeting were worked
out during an August 17,  1989 teleconference between EPA personnel
of the ORD and  the Risk Reduction  Engineering Laboratory  (REEL)
together with members  and staff of the EEC.  on September 18 & 19,
1989, the 1WC& Subcommittee held its initial meeting in Washington,
DC to review the  current MWCA research program  and consider the two
issues of long-term  effects  and  bioavailability/toxicity.   The
documents which  had been made available to the Subcommittee and
were reviewed by its   members prior to that  initial  meeting are
listed in Appendix C.  During the meeting,  the MWCAS was provided
copies of the briefing materials used by Mr.  Carlton C. Wiles of
the RREL.

-------
     The ORD staff has organized a Technical Advisory Panel  (TAP)
consisting of  approximately 26  experts from various  agency and
interested organizations  and has  used the group  effectively in
guiding the management decisions  for the program. The Agency  staff
is to be complimented for their use of peer review for its research
program.


3,0  LONG-TERM EFFECTS

     The  first issue  the  MWCAS  considered had to do  with the
testing   required   to   enable   the   prediction   of   long-term
environmental effects  of products made from MWC ash residue. The
MWCAS made the following observations:


     a. Any	test	routine	used to  predict  long-term effects must
apply tothebehaviorofvarious products of different ashes .from
different incinerators	_ produced,by different S/S processes, .under
both.. dj.s|3o.saj.. conditions,, and,	for different	_reu_se§_. __A _single-site
assessment is not expected. tobe adequateJso	provide, data which are
applicable to  the highly_variable array of ashes  from  the^ many
municipal combustion facilities.

     The selection of  an ash management practice,  a S/S process,
or use of ash products depends largely on ash characteristics.  Ash
(fly ash, bottom ash or combined  ash)  should be tested for quality
and variability of the ash at several sites.  The phase I program
is limited to ash from a single site.  Therefore, the results may
not be broad enough to be applicable to the highly variable  array
of ashes from the many municipal combustion facilities.

     The criteria for  site  selection should include data availa-
bility,  such  as  the  approximate waste  input  composition, the
incineration  system  design and  operating  conditions,  and the
performance of the air pollution control device(s)  used with the
municipal  waste  combustor.   Such data  are valuable  for  under-
standing and managing the overall solid waste and incineration ash
programs.

     Tests to  be used will  depend  on  what products  are  being
tested, what process was used  to produce them,  and what scenario
is to be mirrored.  The facility used to produce the ash, the air
pollution  control devices  installed  and the performance  of the
devices  and  the process by which the ash is treated  for S/S should
be identified  and described.   Fly ash will be the most difficult
residue  for  which  to predict  long-term behavior,  because that
behavior   will  depend  significantly   on  ash  characteristics
determined primarily by the combustion conditions and secondarily
by the air pollution control devices which captured the ash.

-------
     Although present practice generally provides for combined ash
disposal, the  research should be directed  toward  evaluating S/S
processes separately on fly ash and bottom ash,  as well as combined
ash.  Certain S/S processes might very well be more applicable to
either the fly ash or bottom ash long-term disposal problem.


     b.  Addressing  long-term   (and   short-term)   environmental
behavior  requires  a  fundamental  understanding  of _geochemica!I
reactions  expected  to  cause  the  leaching:  and mobilization  of
chemicals Contained  in	the residues._	It is therefore recommended
that  the  research  plan   focus  on the  solid phase,  including
identifyingthe original quantities.chemical speciesandphysical
forms of inorganic chemicals  of interest.  Furthermore,laboratory
tests  should be  conductedtodevelop data  for  specifying the
mechanistic basis that would quantitatively deJfine the breakdown,
the	exposure of surfaces  and resulting	releases	_of :the	_chemica_ls
from the s tab i1 i zed products«

     To  address  long-term  environmental behavior  of  products
prepared by  S/S of MWCA,  the EPA ORD  plans to carry out several
laboratory tests  and measure concentrations of chemicals  in the
aqueous  extracts.   These  tests  span   from  regulatory  extraction
tests  (i.e.,  TCLP)  to  monolith  leach  tests  for  estimating
diffusion-dominated, transfer of chemicals into the aqueous phase.
In addition to the leaching tests for untreated and treated MWCA,
several physical tests  will  also be carried out.   The scientific
principles underlying the long-term behavior of chemicals in waste
are intimately connected  to  dissolution reactions  between solids
and liquids.   Therefore tests on the  solid phases  are needed in
addition to leachate solution tests.  An accurate understanding of
these reactions and  quantification based  on data  from laboratory
experiments  can  provide  a   capability  to  predict  release  of
chemicals from MWCA products.

     Two options are available to address  the science and the data
needs for long-term predictions.  The first approach is fundamental
and provides a mechanistic understanding of applicable equilibrium
and kinetic  reactions,* but  it uses relatively short-term input
data.   The  second approach  is  empirical  and uses  statistical
correlations of  short-term nature.  However,  the  only realistic
option to predict  long-term  behavior  is the fundamental approach
using models with good empirical and necessarily short-term input
data.   The  SPA's  current research plan  appears to  utilize the
second approach.   However, analysis of the data  to  be gathered
through equilibrium  speciation models  »such as MINTEQ and  ECHEM
(Appendix  D,  references  4 and 14) can offer  insights  into the
applicability  of the mechanistic approach to predicting leaching
from the products of MWCA. The aqueous concentration measurements
alone will  not yield the  understanding necessary  for predicting
long-term environmental behavior.

-------
     It Is recommended that the research include an analysis of the
solids for the explicit purpose of identifying quantities and types
of solid  phases of  the inorganic  chemicals of  interest  to the
Agency.  For  a  long-term behavior prediction,,  not only does one
need  to  have  a  specific  identity  of  solubility/dissolution
reactions, but also one needs to know how much of  the total amount
of the chemicals would actually be available  for leaching and how
this relates to the receptor environment,  one additional challenge
in  this  research  program  is  the  ability   to develop  testing
procedures  and  data   for   the  mechanistic  basis  that  would
quantitatively define the breakdown and exposure of surfaces of the
stabilized products.


     c.  There  is  a need to continually evaluate  the  effect of
weather ing and,  for some reuse alternatives,  the dynamic effect, of
abrasion anderosion,  because the physicalchanges ofthematrix
may alter the rate of JLeachinqof the resultant const ituent.sfrom
the matrixand also the mechanical integrityof the material.

     The stability or mobility of the reuse products (such as for
roads,  construction  and various beneficial  uses in the  energy
industry)  should continue to be evaluated both with  and without
weathering, abrasion, and erosion.  The effect these processes have
on the surface area,  and the surface properties of  the solid matrix
must be considered.    This  reinforces the  need for understanding
both  the  chemistry  of the  aqueous phase and  the physical  and
chemical nature of the solid matrix.
     d. Whilemathematicaltransport and fate models  may not be
quantitatively predictive, they may still be useful for determining
which  contaminants  warrant  further  study of  their  potential
environmental  impact^    as .well  as  for  determining  relative
effectiveness	of the various S/S_ treatment: processes«_

     The Subcommittee questions whether existing models for trans-
port and fate of contaminants in  environmental media can be used
to quantitatively predict the migration  of chemical constituents
from stabilized ash.   Also,  difficulty in estimating the rate of
release of contaminants from the solid phase makes the input data
for these models uncertain.   Therefore,  it is very doubtful that
the prediction will  provide the basis for reliable estimates of the
exposure and health  risk to target  populations.   Still,  it is
believed by  the Subcommittee  that  some  of the better transport
models could be very useful in determining which contaminants are
sufficiently mobile to warrant further study.  These models might
be used to analyze the data to indicate the  relative effectiveness
of  the S/S  treatment processes.    If  one  cannot  quantitatively
estimate the mobility of  chemicals leaching from the ash product,
one might, at the very least,  determine  the relative mobility of

-------
the constituents.

     e. Better predictions of  long-termbehavior can be_ madefor
certainchemicals than for others.  Chemicalsshould toeidentified
and focused upon to fill data craps.
     The scientific basis for predicting the leaching of inorganic
chemicals is incomplete for most trace elements.  Although some of
the  major constituents  (e.g., calcium  and  silicon)  have  well
defined  dissolution/precipitation  chemistry,  similar  reliable
foundation needs to be developed for a target set of trace
elements,  it is recommended that selected elements be chosen and
research focused on  the development of the data to  fill  the key
data gaps hindering  capability to accurately predict  release of
chemicals from residues or stabilized products.

     Since this research is to fill data gaps on MWCA S/S products,
there are many constituents  which  are  being  analyzed even though
they  may  not   be  present  in   appreciable,   or  significant,
quantities.   Therefore, it is very  important that appropriate data
analyses be carried out on a real-time basis to identify as early
as possible  those  chemical constituents  that need to  be  focused
upon.


     f, Thehighsalt  contentof MWCA  couldlimit the long-term
usefulness  of  concrete   for  reuse.    Further  examination  of
acceptable standards for allowable salt content of aggregate used
for reinforced concreteis recommended.

     There is need to evaluate  impacts of various chemical species
(e.g.,  sodium,  potassium,  calcium, zinc  and  chloride)  on  the
integrity of  portland-cement concrete in  those cases where the
proposed reuse  of  the stabilized  ash   is by  incorporation into
concrete.  Especially in the case of reinforced concrete products,
where  the  reinforcing  steel  is  susceptible  to  electrolytic
corrosion in the presence  of these ions, there  is  a serious need
to avoid leachable  salts.  These species may also affect properties
related to mechanical fracture and embrittlement.

     Standards have been established for allowable chloride content
of  aggregate used  for reinforced  concrete.   The Agency  should
consult with the various sources of potentially useful information.
For instance, the Highway Research Board, concrete manufacturers,
trade association standards  (such as ASTM Designation; C618-89 or
ASTM  Designation?  C311-88)  and  agencies such  as  the Bureau of
Reclamation   or  the  U.S.  Army   Corps  of Engineers  should be
consulted concerning allowable salt  content,  as  well as  other
specifications that may be of concern when ash is incorporated in
concrete.

-------
     9*   If  microbial activity shifts  the pH or  the oxidation-
reduction  potential  fffh),  the solubility of  toxic metals  can
change.  The effects  of  microblal  actiyity shouldbe included in
the assessment of loner-term performance.

     Microbial activity may be supported by organic matter in the
ash products, or, more likely,  in  the milieu surrounding the ash
product in its place  of  use  or in  a monoflll.   If  the stabilised
ash is used for highway base and is in contact with organics-rich
soil, microbial activity nay change the pH or  Eh.   If MWC ash is
disposed in a monofill, the organic matter in the ash may support
some microbial activity,  but it is more likely to be an inorganic
interaction  phenomenon.   Long-term  environmental  performance
assessment should take these possible changes  into consideration
when studying the solubility of metals.


     n*  The tendency of the ash matrix to swell upon adsorption
o_f_ moisture may have long-term  adverse effects on some uses of the
stabilized product.   Tests should  incorporate  this phenomenon in
the evaluation procedure.

     There is a need for incorporating some test in the evaluation
procedure to obtain an indication of expected swelling due to the
hygroscopic nature and surface features of the ash  mixture.  Many
road base and  sub-base construction requirements cannot tolerate
large  amounts  of  ash  or   S/S  ash products  because  of  this
hygroscopic property and the numerous freeze-thaw cycles.


4.0  BIQAVAILABILITY/TOXICITY

     The Subcommittee  was also asked to comment on possible tests
to evaluate the toxicity  and bioavaliability of MWCA S/S products.


     a.   The committee recommends  that the potential for toxicitv
and bioavailabilitYof MWCA S/S  be  examined as separate phenomena*

     Bioavailability can be demonstrated  by measuring the uptake
of the chemicals of interest into organisms.  Alternatively, when
exposed  organisms  respond   with   physiological  or  pathological
changes, then by implication the compounds or some  ingredients of
the mixture have been demonstrated to be toxic.

     Existing  laboratory methods  are adequate  to  examine  many
aspects of bioavailability in animals and plants under standardized
conditions (Appendix D, reference 26). However, the applicability
of these methods to complex situations, such as the bioavailability
of substances in amended  soils  to plants and animals, will require
validation  of   existing  tests   or  the  development   of  new

-------
methodologies»


b.   Sioassays.  like  chemical  analyses.  are  only  tools  in the
assessment of the potential  environmental  impact of disposal and
reuse alternatives.,

     Prom the information received by the MWCAS, it is clear that
at present  the  potential  roles of  various forms  of biological
testing for  the assessment of  ashes and ash  products  are still
poorly defined.  The Agency appears to champion the position that
bioassay results can  be used directly to assure the  public that
appropriate policy decisions are being made.  However, bioassays are
no more than tools in such assessments. The  most  important aspects
in the use  of these tools are the specific applications and the
proper interpretation of the results.

     Sometimes  the  most  difficult  decisions  relate  to  when
bioassays are the most appropriate tools to  use,  given the expense
and difficulties in  interpretation of many bioassay results.  Thus,
to date it has not been found to be necessary to  conduct bioassays
or risk assessments on other recycled resources, such  as glass,
paper, and aluminum cans.

     Prom a technical point of view alone, a number of issues need
to  be  considered   to  evaluate  the   desirability of  biological
testing.  In toxicity studies the responses  of organisms, specific
organs,  or  cellular  components are measured   in  relation  to
exposures to specified concentrations of compounds or mixtures of
compounds, preferably at a graded series of concentrations.  Each
biological test  has specific strengths  and specific limitations,
because such tests  are in  fact model systems  where  each test
examines only  a specific aspect of  the  "real  world"  conditions.
Biological systems  incorporate  a complex system of chemical and
physical phenomena,  and therefore the interpretation of tests done
on biological model systems is exceedingly complex.  In any event,
bioassays need to be supplemented by leaching tests and models to
predict exposure conditions likely to be encountered in the real-
world environment.
c.   No	_ single  Jaiojissay,  procedure  can	 adequately  assess  the
biological effects	of residue	reuse and/or disposal alternatives.

     Should it be found to be necessary to conduct bioassays
because potential  exposures  derived from MWCA  S/s  materials are
deemed to be high, then  no single bioassay procedure exists that
will adequately demonstrate the multiple toxicological end-points
that  could  potentially occur.   This  will  reguire a  battery of
bioassays using a  range  of  test  species.   Ancillary  problems
include  the great variability  of components  in  the  ash,  and
differences in the physical  characteristics  of  the ash that will

-------
ultimately affect the biological availability  of  such components.


d.   While limited in scope, bioassavs cantoeused effectivelyfor
making relative,. eompa|'lsgjns_of the	taxiiiities_.of leachates derived
from	various ashesand products jer_iveclfrom MWCA.

     Bioassays in their broadest sense are tools  that can be used
for many  purposes.   Among these are  evaluations of  comparative
toxicities of  leaehates derived  from various  ashes and  various
products  of  ashes.    Such  evaluations  are much  more limited  in
scope, but  can assess  the interacting  effects of components  in
mixtures within the limitations of the specific bioassay procedures
utilized.  Such studies can be relatively inexpensive and can  be
used as an adjunct to chemical analyses.


e.   Ijb Is important to establish (as a_ baseline) the -background
bioavaliability of the .e.on.ajcit_uentsjpf_Jjit.eres.t_ for the environment
into., which. ^e._g./Sr_igg£Aj_progMCt-.s._	are to  be utilized.

     Absent   any   credible   baseline    information,    expected
perturbations  to  the   ambient   environment  due  to   S/s  MWCA
constituents cannot be  established.   The assessment  of  potential
risks associated with ash  and products derived from  ash needs  to
be compared with an assessment of  the background concentrations  of
the same  compounds that  may already  be present  due to  natural
sources  or due  to normal human  activities.   This  approach  is
encouraged  as  an  adjunct  activity,   because  comparative  risk
assessments have a much firmer scientific basis than  absolute risk
assessments.
f,   Another approach	is_	to base theapproval, of reuse and .disposal
alternatives on  conf irjiat j.on that	the leachate from. S/jS jaroducts
meet some  multiple of driolcing Mater standards or  Mater  cpaajjlty.
criteria.

     If  realistic   methods  could be  developed  which  produce
conditions similar to those produced under "real world" conditions,
then a comparison  of the contaminant concentrations  found in the
leachatea with published water quality criteria and drinking water
standards  would  allow  an  initial  evaluation  of  the  relative
toxicity for the protection of aguatic life and human health*  The
Agency does have considerable information on bioconcentration, and
this phenomenon has been made an integral part of the present water
quality criteria.   It should be  noted that the bioconcentration
issue has been found to be important for highly hydrophobia organic
chemicals, but is generally not important for inorganic chemicals,
with a few notable  exceptions (e.g.,  mercury).

-------
5.0  OTHER RELATED ISSUES
a.  The SubCQimitteeis concerned that the,level, of funding forithe
municipal waste combustion ash research program may be inadequate.

     It is estimated  that at present there are approximately 200
municipal waste incinerators in operation or under construction and
that over 100  municipal  waste incinerators are under procurement
or in the planning stages.   The construction cost of each is in the
range  of tens  of millions  to several  hundreds of millions  of
dollars.  This represents  a  national  investment  of perhaps $17
billion  (See  Appendix D,  references  29 and 30  and  note below) .
Each  of these  200 municipal  waste incinerators is facing the
problem  of  what  to  do  about its  ash  residues.   The  over 100
municipal waste incinerators yet to be built will also face these
same problems with the ash residues.  The estimated ORD budget for
the Phase I S/s research program is less than $1 million.   It seems
inadequate that only 0.006 percent of the Federal component of the
public investment is being devoted to solution  of the ash disposal
problem within the ORD budget.

     At its initial meeting, MWCAS heard presentations from persons
associated with  state agencies and  academic institutions in New
York and  in  Florida.   It was  learned  that  these states are each
devoting more  financial  resources to MWCA  research than is EPA.
The  Agency   should continue   to  leverage  funding its  research
programs with state and private entities.

     We recommend  that funding for MWCA research be reviewed for
adequacy in light of the  above. We also recommend that the Agency
track  significant  federal, state, municipal,  and private sector
activities in municipal waste  combustion.
NOTE:     Personal  communication of March  20,  1990  Between Mr.
          Steven Levy of the USEPA Office of Solid Waste with Dr.
          K. Jack Kooyoomjian of the Science Advisory Board staff.
                     Combined Total ApproKL. Cost    jkpprgx..Total
                     Capacity       To Construct    Cojpstruction
Facilities  llymber   fTons/Dav)    Per Ton capacity  costlBillions)
In Operation  167     91,705
Under Con-
struction      39     40,586
Under Pro-
curement       63     56,086
In Planning
Stages
51
                        $75,000

                       $100,000

                       $125,000
         $6,9

         $4.06

         $6.26



Total = $17.22
                                10

-------
b. The municipal _wastecombustionash  research,  should emphasize
front-endprevention instead of back-jmd treatment.

     MWC ash quality  is the Jcey to proper  ash disposal or reuse
that affords adequate protection to the environment*  Ash quality
differs among  fly  ash,  bottom ash, and combined  ash.   It varies
with input waste characteristics, design and operating conditions
of an incinerator,  and to some extent to the air pollution control
device used.   Obtaining a  good  knowledge of  highly  varying ash
quality could, be difficult  and costly.   However,   if undesirable
chemical or  consumer  products in  the  waste can  be  prevented by
front-end removal  activities, then the  quality of ash could be
improved  for   either   disposal   or  reuse   without  exceeding
environmentally acceptable levels or performance specifications for
ultimate use end-products.


c. Potentialrisks associated withashdisposal should be compared
with  risksassociatedwith  alternative municipal, solid  waste
d.is_BQ.sal options.

     The risks inherent in municipal waste incineration, including
the ancillary risles due  to disposal of residuals from incineration,
are  receiving  a great  deal of attention by  the  public  and the
Agency.   In many  ways  the concerns  seem  to  be on  a mutually
reinforcing  spiral.   The  anticipation appears  to  be that  all
aspects associated with  the incineration process would be free of
health risks.  At the same time it is clear that other legitimate
solid  waste disposal  management  options  for the  handling of
municipal waste,   such   as  recycling and  landfilling, have  not
received the same level of scrutiny as ash disposal options.   This
appears to be due to a lack of data and  due to preconceived notions
that these processes are relatively free of risks so that they do
not merit investigation.  This sentiment may be misplaced and may
lead to inappropriate  actions  relating to the minimization of risks
associated with waste disposal options.
                                11

-------
           APPENDIX A - THE CHARGE TO THE SUBCOMMITTEE


Based on materials submitted  to  MWCAS and conference with Agency
personnel, the following charge for the Subcommittee evolved;

     a) continuing review of the ORD MWCA research program, and

     b) consideration  of two  issues  related to the  current s/s
     demonstration.  These two issues,  considered  at the initial
     meeting of the Subcommittee, were (1) the appropriate testing
     procedures to be  applied to the S/s ash  products and reuse
     products  made  from  the S/S  to  determine  the  long-term
     environmental effects, and (2) appropriate methods of testing
     to determine  the bioavailability  and  "biotoxicity"  of S/S
     products.
                                12

-------
           APPENDIX B - GLOSSARY OF TERMS AND ACRONYMS

ASME-     AMERICAN SOCIETY OF MECHANICAL ENGINEERS
EEC-      ENVIRONMENTAL ENGINEERING COMMITTEE OF  THE
            SCIENCE ADVISORY BOARD
ECHEM-    EQUILIBRIUM CHEMISTRY (GEOCHEMICAL COMPUTER CODE
            FOR SPECIATION OF INORGANIC CHEMICALS)
Eh-       OXYGEN-REDUCTION POTENTIAL
EPRX-     ELECTRIC POWER RESEARCH INSTITUTE
EPA-      U.S. ENVIRONMENTAL PROTECTION AGENCY
MINTEQ-   A COMBINATION OP TWO EQUILIBRIUM aEOCHEMICAL
            COMPUTER CODES (MINERAL EQUILIBRIUM CODE (MINTEQ) AND
            SPECIATION CODE  (WATEQ3)  FOR SPECIATION OF INORGANIC
            CHEMICALS)
MITE-     MUNICIPAL INNOVATIVE TECHNOLOGY EVALUATION
MSW-      MUNICIPAL SOLID WASTE
MWCA-     MUNICIPAL WASTE COMBUSTION ASH
MWCAS-    MUNICIPAL WASTE COMBUSTION ASH SUBCOMMITTEE
NTIS-     NATIONAL TECHNICAL INFORMATION SERVICE
ORD-      OFFICE OF RESEARCH AND DEVELOPMENT OF THE U.S. EPA
OSW-      OFFICE OF SOLID WASTE OF THE U.S. EPA
pH-       THE NEGATIVE LOG OF THE HYDROGEN ION CONCENTRATION
RREL-     RISK REDUCTION ENGINEERING LABORATORY OF THE U.S. EPA
SAB-      SCIENCE ADVISORY BOARD OF THE U.S. ENVIRONMENTAL
            PROTECTION AGENCY
S/S-      SOLIDIFICATION/STABILIZATION
TAP-      TECHNICAL ADVISORY PANEL
TCLP-     TOXICITY CHARACTERISTIC LEACHING PROCEDURE
                                13

-------
         APPENDIX C - INITIAL REVIEW DOCUMENTS
Item It A copy of the Request  for Participation that has been
sent to potential  participants. This  document describes the
S/S program, but concentrates  on Phase I.  This document also
includes   tables  of  tests   and   analyses  proposed  for
characterizing  and  evaluating the   untreated  and  treated
residues.

Item 2s A  list of members  of the Technical  Advisory Panel
(TAP)  which was established  to assist  in the  selection of
tests  and  analyses   to  be used,  evaluation of  potential
processes for including in the program, evaluation of data and
similar aspects  of the program.   This panel  was considered
necessary  to  have a  program  that  is credible to  state and
local authorities likely  to  implement  potential processes, as
well as the public.

Item 3: A copy of cost estimates prepared for conducting Phase
I.  This estimate  was prepared by a  small sub-group  of the
TAP.

Item 4:  Several items of information which provide background
on  the generation of  the  program and previous  activities,
These  include a letter  from  Carlton  c.  Wiles to  the TAP,a
letter from Carlton C. Wiles to John H. skinner dated Oct. 27,
1988 describing  the  S/S  program, and  a letter from wiles to
Skinner dated March  4,  1988 submitting a proposed plan for
the S/S program.

Item 5:  A description of the Municipal Innovative Technology
Evaluation  (MITE)  program.  The  MWC  Ash  S/S  program  is now
being considered a MITE prototype.

Item 6:  Some issues which will or may affect  the conduct and
outcome of the program.

Item 7:  A letter from Wiles to Kooyoomjian dated June 5, 1989
identifying other quest ions/issues on which MWCAS could focus.
                           14

-------
                 APPENDIX D - RESOURCE MATERIAL

1)    ASME  White  Paper on  Research  Needs  for Municipal  Waste
     Combustor Residue Management, 1988, 10 pages

2)    ASTM, Standard Specification for Fly Ash and Raw or calcined
     Natural Pozzolan  for Use as  a  Mineral Admixture in Portland
     Cement Concrete, Astm Designation G618-89, pages 296-298

3)    ASTM, Standard Test Methods for Sampling and Testing Fly Ash
     or  Natural  Pozsolans  for Use as  a  Mineral  Admixture  in
     Portland Cement Concrete,  Astra Designation C311-88, pp. 185-
     189

4)    Battelle Pacific  Northwest Laboratory, FASTCHEM™,  Package,
     Volume 4, User's Guide to the ECHEM Equilibrium Geochemistry
     Code, 1PRI Report Number EA 5870-ccm, September 1988

5)    Baumeister,  T,   ed.,   Standard  Handbook   for  Mechanical
     Engineers,  McGraw-Hill Book Company, New York,  1978

6)    Briefing  by  EPA's  ORD  Staff  entitled  "Municipal  Waste
     Combustion Ash solidification/stabilization Program"1
     dated Sept. 18-19, 1989, 22 pages

7)    Briefing by EPA's ORD Staff entitled "III Review of the
     Municipal Waste Combustion Ash Solidification/Stabilization
     Program Design," Sept, 18-19, 1989, 27 pages

8)    Briefing by  EPA's ORD Staff entitled,  "IV. Key  Issues and
     Program Directives," Sept.  18-19, 1989, 18 pages

9)    Briefing by EPA's  ORD  Staff,  Three  tables  entitled  (1)
     Measured Concentrations of Metals in the Extract from EP Tox
     Tests from Various Processes and Sites; (2) Ranges of Values
     of Toxic Metals in MSW  Combustion  Ash?  (3)  Ranges of Values
     of Tox Metals in MSW Combustion Ash, 3 pages

10)  Cal  Recovery  Systems,  Inc.,   North  Santa  Clara  County
     Comprehensive Waste Characterization Study (1982-82), Report
     No. 83-10,  January 1984

11)  city of Los Angeles, Bureau of Sanitation, unpublished data,
     1983

12)  EPA Memo with attachments,  Wiles, Carlton C, to Kooyoomjian,
     K. Jack, entitled "Information for SAB Review of EPA MWC Ash
     S/s Program," May 11, 1989

13)  EPA Memo, Wiles, Carlton C. to Kooyoomjian, K. Jack entitled,
     "SAB  Review of  EPA MWC  Ash  Solidification/stabilization
     Program," June 5,  1989, 2 pages

                                15

-------
14)   Felmy, A.R., D.C. Girvin and E,A. Jenne,  MINTEQ:  A Computer
     Program for Calculating Aqueous  Geocheraieal  Equilibria,  EPA
     Report Number 600/3-84-032, 1984  (Also  available  from NTIS,
     Springfield, VA as NTIS Report Number PB 84-157148),


15)   Franklin Associates, characterization on Municipal Solid Waste
     in the United States,  1960  to 2000, a report prepared for the
     USEPA, Contract No.  68-01-7037, 1986

16)   Franklin,  M.A,,  "Characterizing the Municipal Waste Stream,"
     presented at  the Third  Annual  Symposium on Materials  and
     Energy Recovery  from  Municipal Solid Waste,  October 20-22,
     1987

17)   Franklin Associates,  Characterization of Products Containing
     Lead  and  Cadmium in  Municipal  Solid Waste  in the  United
     States, 1970-2000. Executive Summary. EPA/53Q-SW-89~015c

18)   Hartlen,  Jan.Dr., Director General,  Swedish  Geotechnical
     Institute, "Incinerator Ash Utilization In Some Countries In
     Europe," pages 33-47,  no date

19)   H.R.   2162,   101st   Congress,   1st   Session,   House   of
     Representatives Bill Dated May l, 198S, To amend  Subtitle D
     of the Solid Waste Disposal Act  to  regulate municipal solid
     waste incinerators and municipal  solid waste incinerator ash,
     19 pages

20)   Kaiser,  E.R., D.C.  Zeit,  and  J,B.  MeCaffery,  "Municipal
     Incinerator  Refuse  and  Residue." Proceedings  of  the  1968
     National incinerator Conference,  ASM!, May 1968

21)   New York State Department of Environmental Conservation, Ash
     Residue Characterization Project Report, July 1987

22)   Savage, G.M.  and J.c.  Glaub, "Approaches to  Coupling  the
     Design  of  Resource   Recovery  Facilities  to  Performance
     Specifications and Acceptance Testing,"  Proceedings  of the
     llth  National Waste  Processing  Conference,  ASMS,  Orlando,
     Florida, June 1984

23)   SAB Report of the Environmental  Effects,  Transport and Fate
     Committee entitled "Evaluation of Scientific Issues Related
     to Municipal Waste Combustion,1* SAB-EETFC-88-25, April 1988

24)   SAB  Report   of   the   Environmental  Engineering  Committee
     entitled, "Resolution on Use of Mathematical Models by EPA for
     Regulatory Assessment  and  Decision-Making," EPA-SAB-EEC-89-
     012, January 1989
                                16

-------