UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON. O,C. 20460
1988
OFFICE
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The Subcommittee appreciates the opportunity to conduct this particular
scientific review. We request that EPA formally respond to the scientific ad-
vice provided in our evaluation,
Sincerely
Norton Nelson, Chairman
Executive Committee
Richard A. Grieseiner, Chairman
Environmental Health Coamittee
GaryTP. Carlson, Chairman
Drinking Water Subconroittee
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Review of the Office of Research arid osvelcpnent' s
Drinking Water Distribution System Research Program
by the
Drinking Water Subcommittee
Environmental Health Committee
Science Advisory Board
Summary
The Drinking Water Subcommittee has completed its evaluation of the
Office of Research and Development's (GRD) Drinking Water Distribution System
Research Program following its public meeting on December 3-4, 1987 in Cincin-
nati, Chio. This is part of a series of research program review conducted by
the Science Advisory Board (SAB) and is designed to advise the senior officials
of the U. S. Environmental Protection Agency (EPA) on the quality, research
relevance and future needs of Agency research programs, ihe SAB Executive
Committee assigned this particular review to the Drinking Water Subcommittee
of the Environmental Health Committee.
As with previous research program reviews, CRD prepared a background docu-
ment presenting the basic components of ongoing research* This document, en-
titled "The ORD Control Technology Research Program on Control of water Cuality
in Drinking Water Distribution Systems," was prepared by the Drinking Water
Research Division of the Water Engineering Research Laboratory. Along with
staff briefings at the meeting, it served as the basis of the Subcommittee's
review, ihe Subcommittee focused upon the program as a whole, while also
consenting upon its three main components! microbiology, corrosion and cost
modeling.
The Subcommittee's major conclusions and recommendations are as follows:
o Ihe research program needs greater cohesiveness both in terms of scientif-
ic integration and research planning. Ihe Subcommittee had difficulty
identifying the relationship of the ongoing work of this program to
CRD's efforts in general. In addition, there is need for improved
coordination among the program's existing three components. For
example, work on the modeling of drinking water quality requires
closer integration with work on the effects of corrosion upon microbial
growth.
o in the area of microbiology research, the AssiMliable Organic Carbon
(AQC) studies merit additional support, to establish whether or not
microbiological contaminants are growing within the distribution
system, to identify contributing factors, and to provide sufficient
information for regulatory decision making.
o The declining support for research on corrosion appears short-sighted.
There are, for example, a number of unresolved scientific and policy
issues related to the public health threat posed by the leaching of lead.
Second, the issue of the corrosion of asbestos pipe is of public health
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concern, Vihile not currently a high priority issue within EPA, the
Subcommittee believes these issues will grew in importance - In order to
be prepared for this development, EPA should continue research on
studies relating to mitigation measures. EPA roust also expect to
confront issues relating to the mechanisms of corrosion by which other
metals, such as copper and cadmium, enter drinking water.
o ihe Subcommittee recommends the termination of the cost modeling studies
because of their apparent lack of integration within the existing research
program and the availability of similar modeling systems.
o Water quality modeling studies should continue but with refinement in
the research objectives and appropriate verification measures. The
emphasis of such studies should include: additional information on
the dispersion of chemicals in the distribution system (kinetics), and
biofilw interactions and changes in the chemicals themselves while in
the distribution system.
Specific Technical Ccnroents_jon_ Components of the_ Research Program
A. Microbiology
Microbiology research has been of consistently high quality, and this is
reflected by the numerous publications of the staff in peer reviewed journals,
Previous research efforts have contributed significantly to an improved under-
standing of the behavior of micro-organisms in water distributions sytans.
Efecreased funding has caused the program, in the recent past, to become
too narrowly focused. The research program document identified several issues
that the Subcommittee believes are of high priority and necessary to regulatory
decision making, these include:
o Continuing the investigation of alternative disinfectants and surveying
the number of reported incidents of the occurrence of colifom bacteria
in the presence of free chlorine residuals. In addition, these research
efforts could contribute significantly to reducing costs associated with
the corrosion of distribution systems.
o Determining the effect of organic matter on microbial contaminant control.
Ihe major future effort should be directed toward defining the effect of
assimilable organic carbon (AOC) in distribution systems on bacterial
growth including both heterotrophic plate count (HPC) and coliform organ-
isms. Another important factor that should be pursued is the role of AOC
upon opportunistic pathogens, focused especially on the increased potential
for amplification in the distribution system.
There is a serious problem with the level of funding projected for micro-
biology research, if current levels prevail, the Icjency will not have generated
the data needed to support the alternatives in treatment called for in the up-
coming regulatory action for trihalomethanes (THM). Water utilities will have
to comply with the njgw TIM regulation, it is likely that many new treatment
technologies will be available to enable them to do so. Ihe majority of the
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population will look for EPA to provide public health protection and obtain it
for a research investment of approximately a $300,000 per year effort. What
is perplexing to the subcommittee is that EPA has already devoted more resources
to research that is not as directly linked to its regulatory needs (e.g. chlorine
induced arteriosclerosis). Hie Subccnmittee recarmends that EPA reconsider how
to achieve a better balance between its research planning and its regulatory
needs,
Limited resources have had other consequences such as removing research oppor-
tunities for in-house scientists. Other regulatory agencies* such as the Food
and Drug Administration, have taken advantage of recent advances in molecular
biology and biotechnology by reorienting their research programs* At present,
there is little or no opportunity for EPA scientists in this program to achieve
similar advances.
B. Corrosion
Ihe written and verbal presentations of the corrosion research prcgran
indicate that the available time and money have allowed these achievements
productive results. Specific achievements include findings that:
o Excessive leaching of lead from certain brass faucets.
o Water quality indices are not reliable predictors of corrosion.
o Protective films can be formed on asbestos/cement (AC) pipe.
o Elucidation of the role of pH on lead leaching.
o Demonstration of the role of treatment in reducing corrosion by-products
in the Seattle distribution system*
o Assessment of the suitability of tin/antimony solders in distribution
system.
o Decreased leaching from tin/lead solders with age.
The Subccmraittee is concerned, however, that the efforts in corrosion
research appear to be diminishing at a time when public concern over health
risks is rising and when significant unanswered questions related to corrosion
by-products remain. If funding for in-house and extramural research is not
available, the Subcotnnittee recommends that, at the very least, a minimal
expertise in corrosion research be maintained to enable EPA scientists to
obtain and make wise use of information generated by the private sector and
other organizations.
The Subcommittee recommends that several specific corrosion research issues
need to be addressed by EPA:
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o Water quality and corrosion. Uncertainty remains about the relation-
ship between water quality and corrosion. A national field survey of
water quality and its effect on corrosion could elucidate this rela-
tionship. Although lead has received considerable attention, other
metals, including ironr copper and cadmium, should be addressed.
o Field studies on corrosion treatment. Field studies should be con-
ducted on treatment methodologies to reduce corrosion, selecting
several communities in the National Corrosion Survey that have above-
average concentrations of corrosion by-products.
o Impact of banning lead in plumbing. Mthough in the long run, the
banning of lead will reduce lead exposures from potable water, the
possible negative impacts of alternative materials should also be
investigated to avoid unpleasant surprises* Candidate materials for
additional research include plastic and stainless steel pipe.
o Relationship between corrosion and conforms. Corrosion and micro-
biological contamination and growth in distribution systems are often
related. EPA studies in these areas should be integrated into a
' cohesive effort.
o Asbestos. The Subcommittee is not convinced that the issue of adverse
health risks from asbestos exposure in drinking water has been resolved
including potential inhalation exposure from the re-entronment of
asbestos from previous water used. EPA should continue to maintain
an active research effort for this issue.
o Paintings and linings. EPA should consider establishing a program to
evaluate methods for assessing the leaching of chemicals from coatings
and linings used in water distribution systems.
C. Cost Modeling
The Subcommittee concludes that water quality simulation research should
receive the highest priority within the modeling and cost estimation area.
This applies to both the presently scheduled evaluation in New Haven, to be
conducted by the University of Michigan, and to future research efforts*
The Subconmittee recognizes the potential for utilizing water quality simula-
tion as a means to identify representative monitoring locations within the
distribution system. Another logical application is to define the variation
of water quality on a temporal basis in order to address the changes that
may occur between sampling at specified frequency.
The soon to be initiated North Penn water Authority study to evaluate
expert system technology provides an opportunity to assess the applicability
of this approach to water distribution systems. The Subcommittee supports
the objective of this study and the insights it can provide for applying
expert systems within the water industry. Upon successful completion of
this study, the Subcommittee urges the Office of Research and Envelopment to
evaluate the need for a follow-up study at a larger, more complex water system.
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Future efforts in water quality simulation should center in at least
three areas. • These include:
o incorporating dispersion of substances.
o Evaluating the chemical kinetics of non-conservation [Rick: is this
the right word?] substances.
o Simulating the transfer from biofilms on the pipe surface*
At present, there are no planned projects in these areas. Jte the New Haven
study is conducted, the Subccmtiittee reccmnends that the Office of Research
and Development evaluate the potential for expanding the number of parameters
beyond those investigated in the North Penn Water Authority study, to inves-
tigate the desirability of including dispersion and kinetics and to formulate
proposals for future research,
The Erinking Mater Research Division's studies on pipe replacanent/rehab-
ilitation/repair will be completed in the near future* !hese studies provide
much insight into the factors that need to be considered in assessing the
history of pipe breaks, costs and causes leading to pipe replacement decisions.
and repairing distribution mains. They have also established an excellent -
data collection system and data base that it available for many future studies.
Ihe Division conducted a thorough peer review in March 1987, and the Subcommit-
tee concurs with observations made at that time, particularly the requirement
for independent verification. Ihe Subcommittee commends the Division on the
work conducted to date. However, it agrees with its decision not to use
limited research funds in this area in the near future because this work
is also being conducted by other research organizations.
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