5 STAR

REPORT

Vol.2 Issue 3 April 1998 A product of the National Center for Environmental Research and Quality Assurance

The United States enjoys one of the best supplies of drinking water in the world.

Ninety percent of Americans receive their tap water from public water systems (PWSs)

regulated by EPA and the states or tribes.

DRINKING WATER RESEARCH

U.S. EPA Office of Research

and Development’s Science

To Achieve Results (STAR)

Research in Progress

The challenge in delivering safe drinking

water is one of balance. In protecting the public

from health effects caused by microbial pathogens, public water supplies must achieve levels

of disinfection that destroy the greatest number

of pathogens while minimizing levels of disinfection byproducts that might themselves cause

health effects. Providing safe drinking water involves meeting this challenge and simultaneously

complying with federal and state standards that

ensure protection from chemical contaminants.

Tap water that meets all EPA and state standards is considered safe to drink for the general

public. However, there are occasional, rare incidents of disease outbreaks in U.S. populations

served by Public Water Systems (PWSs), in some

cases because standards have not been met, and in

other cases apparently because the standards did

not protect all exposed individuals. In particular, it

has been found that some contaminants in even

low concentrations pose special health risks to

particular groups of people. These groups include

infants, young children and the elderly. They also

include people with compromised immune systems

due to certain illnesses, or because they are undergoing chemotherapy. Drinking water standards are

being strengthened to reduce the risk of outbreaks.

However, some scientific uncertainty remains about

the degree to which current standards and monitoring requirements protect all individuals from all

possible effects of microbial pathogens or chemical

pollutants.

 While typically only very

small numbers, if

any, of U.S.

residents served by

PWSs experience

waterborne

diseases in any

given year, an

unprecedented

situation occured

in 1993, in which

over 400,000

people in Milwaukee became

ill, and there

were 104 deaths of highly susceptible individuals due

to a single outbreak of disease caused by the microorganism Cryptosporidium. At that time, over the course

of one year, approximately 2000 additional U.S

residents experienced a total of sixteen other outbreaks ofCryptosporidium or other microorganisms

(Giardia, Campylobacter, Salmonella and organisms

that cause shigellosis and cholera).
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General Information

Grants described in this report are part of EPA’s Science to Achieve Results (STAR)

program, a major research initiative designed to improve the quality of scientific

information available to support environmental decision making. The STAR program is managed by EPA’s National Center for Environmental Research and Quality

Assurance in the Office of Research and Development (ORD). The program funds

approximately 200 new grants every year, with the typical grant lasting three years.

Funding levels vary from $50,000 to over $500,000 per year, with FY 1998 funding

level at about $80 million for grants to individual principal investigators or groups

of investigators. Additional STAR funds are provided for a number of Research

Centers specializing in scientific areas of particular concern to EPA, and for a fellowship program supporting graduate students conducting environmental research.

Chemical contaminants are

typically associated with fewer than

a handful of nationally reported

acute illnesses in any given year, and

these typically involve contamination

of private water supplies. (Nitrates,

which can cause illness in young

infants at levels that don’t harm

other people, may be the most

common cause of chemicallyinduced illness associated with

private wells.) However, there is

concern among scientists that the

potential for longer-term effects of

all chemical pollutants that may

occur in water supplies is not yet

fully understood. To address these

concerns, and based on requirements of the 1996 amendments to

the Safe Drinking Water Act, EPA has

developed a “Contaminant Candidate List” (CCL) of chemicals not

presently subject to regulation that

may occur in drinking water

supplies, and that have been

identified as priorities for research,

monitoring, guidance development,

and for determining which contaminants need to be selected for

drinking water regulation.

EPA’s Overall Research

Strategy for Drinking

Water

This report summarizes

research grants funded in 1996 and

1997 through EPA’s principal

external research program, the

Science to Achieve Results (STAR)

program. To address microbial

contaminant and DBP issues, EPA has

developed a comprehensive Microbial Contaminants and Disinfection

Byproducts (M/DBP) study plan to

support future regulations for

microbial disinfectants and disinfection byproducts. In addition, EPA

has identified priority research

questions concerning possible

sources of risk from chemicals on the

CCL. Together, these questions form

an overall “Drinking Water Research

Strategy” on which EPA has consulted with other federal agencies,

states, tribes, PWSs and the academic community. Studies summarized in this report support each of

the microbial, DBP and chemical

contaminant components of the

overall drinking water research

strategy.

In addition to the STAR

research described here, EPA, the

National Institutes of Health, the

Centers for Disease Control and

Prevention, other federal agencies

and members of the American Water

Works Association Research Foundation are conducting components of

the M/DBP study plan and CCL

research. More information on EPA’s

drinking water research strategy and

related work by other groups is

available from Internet Websites

listed at the end of this report.

EPA’s STAR grants are typically

awarded for three-year time periods.

On-going research is described in

this report; results will be presented

in future reports as findings are

completed and peer reviewed.

STAR Research Addressing

Drinking Water Issues

Cryptosporidium Research

Cryptosporidium parvum is the

pathogen that caused illness in over

400,000 people in Milwaukee in

1993. Contamination of the city’s

water supply occurred because of

treatment plant failures that let

Cryptosporidium oocysts pass

through filters and into the distribution system. The disinfectant added

did not provide an additional

protective barrier because chlorine

cannot effectively inactivate

Cryptosporidium. Ingestion of a small

number of oocysts may cause illness

in otherwise healthy individuals. The

resulting disease outbreak was

detected because of an increase in

anti-diarrheal drug sales.

Cryptosporidium may be present in

fifty percent or more of the surface

waters in the U.S. at levels that

require careful operation of treatment facilities and for some possibly

a change to a more effective

disinfectant such as ozone. However, data collected on the occurrence of the microorganism is

difficult to interpret because of

current uncertainties concerning

analytical methodology problems.

Four research projects supported by

STAR grants are attempting to

reduce these uncertainties concerning Cryptosporidium monitoring and

disinfection.
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The Metropolitan Water

District of Southern California is

developing an assay to identify live

and infectious C. parvum oocysts

from environmental samples. This

may be useful in developing a

species-specific analytical method for

environmental samples. A method

to monitor oocyst survival will help

to ensure that disinfection processes

have been effective. The genetic

information can be used by other

researchers to refine methods for

studying the growth and infectivity

of C. parvum and other

Cryptosporidium species in laboratory

and field situations. Investigators

hope to increase understanding of

differences between species, and

among individuals of the same

species, which affect how likely the

pathogens are to infect people or

other host organisms. An investigator from Kansas State University is

going to construct DNA libraries for

various species and subgroups of

Cryptosporidium. This

Cryptosporidium genetic information

will support research across the

country, helping others to develop

and verify new analytic methods for

a wide variety of purposes.

St. Luke’s Hospital and the

University of Texas are studying

whether different strains of

Cryptosporidium parvum differ in

virulence (affecting how many

people become ill and the severity of

the illness). Mice and human

volunteers are being evaluated to

determine the typical infectious

dose, and to evaluate individual

responses. In addition to assessing

the clinical response in healthy,

previously unexposed humans to

different strains of C. parvum, the

research examines the immune

response and a number of biological

“markers” that may be useful to

diagnose exposed and infected

individuals. This will also be useful in

assessing the prevalence of

cryptosporidosis in human populations. In work on related issues,

Ohio State University is using pigs

as test animals to study the virulence

of C. parvum isolates. Pigs of

different immonological status

(normal and immunologically

compromised) will be tested to

improve understanding of how this

affects susceptibility to

Cryptosporidium.

Other Microbial

Contamination Studies.

Researchers at the University

of North Carolina at Chapel Hill

are working with human volunteers

to study infectivity of two viruses,

Norwalk virus and Snow Mountain

Agent. They will examine immune

responses of individuals most

susceptible to infection, and evaluate

models of dose infectivity. Results

will help to refine risk assessments.

The 1996 Amendments to the

Safe Drinking Water Act require

disinfection of groundwater used for

drinking water unless “natural

disinfection” can be demonstrated

to occur. Researchers at the

University of California and the

Baylor College of Medicine are

using recombinant Norwalk virus

particles to evaluate their survival in

groundwater. Preliminary data

suggest pH may be the most

important factor. Results of this

research will be relevant to establishing suitable set-back distances

between potential contaminant

sources and intake points.

Enhancing natural bacterial

activity may aid in situ (in-place)

bioremediation of contaminated

ground water. The New York State

Department of Health and the U.S.

Geological Survey are evaluating

field methods to measure bacterial

activity by monitoring oxygen

consumption. Preliminary results

indicate low bacterial respiration

rates in the aquifer, indicating that

introducing oxygen is probably an

effective way to speed up natural

bioremediation. Early results from a

study being done by El Paso

Community College and Texas

A&M indicates that viruses can exist

in groundwater in a “reversibly

inactivated” state, unable to cause

infection until reactivated. This may

explain contradictory results in

testing effectiveness of disinfection

procedures. This study will investigate inactivation mechanisms and

environmental factors that could

promote or retard reactivation.

Monitoring microbial pathogens is often costly and time

consuming. Low sample volume

methods are needed that identify

only live viruses. The University of

Arizona is developing a combined

cell culture/PCR technique for

enteroviruses from sewage. This

technique, combining advantages of

the two approaches, is expected to

be sensitive and cost-effective. (In

addition to drinking water, this is

applicable to marine recreational

waters.)

Fecal coliform contamination

of drinking water sources is monitored with standard tests that do not

distinguish human from animal and

other sources of coliform bacteria.

Human fecal wastes have a much

higher likelihood of containing

human pathogens than livestock and

other animal wastes. In preliminary

studies, researchers at the University

of North Carolina have developed

techniques by which human fecal

contamination can be distinguished

from that of animals or other

wildlife, with the exception of waste

from pigs. These investigators have

received a STAR grant to refine their

methodology. Methods that could

accurately distinguish fecal sources

would help in assesing potential

public health risk.
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Socio-Economic Study of

Protecting Upstream

Water Sources

Cornell University is assessing

public opinion on watershed

protection issues, based on interviews with upstate New York

watershed residents and New York

City residents whose drinking water

comes from the watershed. Results

will provide information useful in the

on-going public process by which

the City, other local governments,

the State and the U.S. EPA are

assessing options for protecting

water quality in the watershed, in an

effort to avoid the need for a new

filtration plant with a projected cost

of $5 billion.

Research Concerning

Disinfection By-products

(DBPs)

Health Effects Studies: The

potential for cancer-causing

effects of trihalomethanes is being

evaluated through rodent studies at

the Medical College of Ohio.

Results should decrease uncertainties

of estimates of the human health

hazards of these DBPs. Investigators

from the University of Illinois at

Urbana-Champaign are evaluating

the use of mammalian cell cultures

rather than bacterial genotoxicity

tests to predict DBP risks. The cell

cultures may be more representative

of potential human impacts.

Investigators at Pacific

Northwest National Laboratories

theorize that the human system can

detoxify small amounts of

haloacetate DBPs from drinking

water, but that ingestion beyond a

threshhold amount results in partial

or complete inactivation of the

enzymes needed for such detoxification. Rodents and human liver cell

cultures will be used to study

whether enzyme inactivation occurs,

where haloacetates are distributed

after ingestion, and how they are

eliminated. Results will allow more

accurate risk assessment for

haloacetate.

Exposure Studies: Exposure

to DBPs in tap water can be

from drinking the water, inhaling

volatile DBPs (for example in

showers and baths) and dermal

exposure. The University of

Medicine and Dentistry of New

Jersey is investigating human

exposure to haloacetic acid DBPs

from dermal absorption and

inhalation, to assess the relative

importance of each exposure route.

Halogenated acetonitriles are

DBPs that are both toxic and

carcinogenic. Investigators from the

University of Texas Medical Branch

are attempting to identify halogenated acetonitrile “biomarkers”,

molecular-level changes in living

tissues that demonstrate they have

been exposed to these specific

chemicals. These could be used to

assess exposure and identify particular affected tissues. The University

of North Carolina at Chapel Hill is

also investigating the chemical

nature and metabolite formation of

haloacetic acid DBPs with an eye to

identifying biomarkers. In particular,

haloacetic acids may form macromolecular adducts that could serve as

biomarkers.

Detection Methods: A new

drinking water standard for the

carcinogen bromate is being

proposed at a level for which good

detection methods are not widely

available. The University of North

Carolina at Chapel Hill is evaluating

a cost-effective ion chromatographic

system for detection of all oxyhalides

(bromate, iodate and chlorite) using

UV spectrophotometry.

Precise, low-cost methods to

measure DBPs called haloacetic acids

are being developed at Pennsylvania State University, using a

technique called “surface enhanced

Raman scattering”. The method

requires a minimum of

expertise to perform and

thus would be practical for

regular on-site monitoring

at treatment plants. The

University of Massachusetts is developing and

refining analytical methods

for DBPs of ozonation

disinfection processes.

Improved Disinfection

Processes: The University of

Washington and University of

Colorado are investigating a method

to reduce the quantity of metal

coagulant necessary for satisfactory

removal of natural organic matter

and particles from drinking water. A

graduate student at Michigan State

University has received a STAR

fellowship award to investigate

methods for reducing DBPs in water

containing natural humic

substances, using ozonation and

biological treatment. This study will

include examining how humic

substances are modified during

ozonation, and the biodegradability

of the ozonation by products, and

will track formation of toxic

organochlorine compounds during

chlorine disinfection.

The University of Michigan

and the Hebrew University are

analyzing the DBPs resulting from a

secondary disinfectant formulation

using hydrogen peroxide and silver.

They are evaluating the method for

use in long-term residual disinfection. The University of Colorado at

Boulder is studying the use of

softening and coagulation treatments to remove DBP precursors as

well as arsenic from drinking water.

EPA STAR RESEARCH: Building a Foundation for Sound Environmental Science

?
5

Other Toxic Chemical

Risks

Rodent studies are being used

at the University of Kentucky and

Purdue University to evaluate brain

accumulation of aluminum from

drinking water. Oral bioavailability,

influence of water hardness, aluminum circulation and elimination

from the brain will be studied.

Princeton University is

studying the role of microorganisms

in arsenic cycling in contaminated

freshwater. Investigators propose

that bacteria convert one form of

arsenic into another, more mobile

form, and also catalyze precipitation

of arsenic sulfides. Results will help

to refine assessments of actual

human exposure and hazard from

arsenic contamination of water

supplies.

Drinking Water Research

in EPA’s Small Business

Innovative Research

Program

EPA conducts a Small Business

Innovative Research Program (SBIR)

to take advantage of the talents of

small businesses to find solutions to

priority environmental problems. A

number of proposals funded

through EPA’s SBIR program are

directly related to and supportive of

EPA’s overall drinking water research

strategy. Subject areas on which

drinking water SBIR projects focus

include developing sensors and

other monitoring equipment for

microbial pathogens, and refining or

developing new removal technologies for contaminants including

DBPs, nitrates and toxic chemicals.

More information about SBIR

research projects is available at EPA’s

website, www.epa.gov/ncerqa/sbir

Future Directions for

Drinking Water Research

A top priority for future STAR

drinking water research is to

complete studies of emerging

contaminants from the currently

drafted CCL. Work funded in 1998

and anticipated for 1999 will

emphasize filling information gaps

with respect to potential health risks

of these contaminants at levels that

are likely to occur in drinking water,

and of the mechanisms (“modes of

action”) by which they might cause

adverse effects.

In addition, future work will

build on the findings of earlier work

concerning microbial pathogens,

moving into establishing approaches

for determining the general impact

of susceptibility factors (e.g., age,

pregnancy, nutrition, protective

immunity, pre-existing diseases, and

behavioral patterns) on infectious

disease incidence associated with

exposure to primary waterborne

pathogens and to emerging pathogens. At present little is known

about the occurrence of some

emerging pathogens in U.S. source

waters. It is possible that some of

these poorly understood pathogens

may have caused some disease

outbreaks for which no explanation

has yet been found. Analytical

methods to detect emerging

pathogens will be a principle focus

of this future research. In another

area of microbial research, methods

for counteracting the action of

“biofilms” that can form in treatment systems and protect pathogenic microorganisms from disinfectants will be also be a subject of

future study.

In the area of DBPs, much of

the research work already completed

or now underway is paving the way

for improved and more cost-effective

techniques for treatment by large

and small PWSs. But additional

research is still needed relative to

some disinfection processes. The

technique of ozonation followed by

a secondary disinfectant is a potential treatment alternative for water

utilities to avoid chlorinated

byproduct formation. However, the

reaction of ozone with natural

organic matter is not entirely

understood, so research will be

supported to identify and quantify

byproducts of ozonation and

secondary disinfection as a function

of source water quality.

Find Out More About the STAR Research Program

General information on EPA’s STAR research program is available from

the following sources:

ORD’s National Center for Environmental Research and Quality Assurance

(NCERQA): Internet website: http://www.epa.gov/ncerqa

Mailing Address:

Office of Research and Development

National Center for Environmental Research and Quality Assurance

Office of the Director (8701 R)

401 M Street, SW

Washington, DC 20460
 STAR Research Projects Described in this Report

United States

Environmental Protection Agency

Mail Code 8701R

Washington, D.C. 20460

Offical Business

Penalty for Private Use

$300

EPA/600/F-98/010

Development of a Quantitative Cell

Culture-Based Infectivity Assay for

Cryptosporidium parvum in Source and

Finished Water. Metropolitan Water

District of Southern California.

Genomic Database for Cryptosporidium

spp., Kansas State University.

Virulence Factors in Cryptosporidium and

Infective Dose in Humans. University of

Texas.

Understanding Risk Factors to

Cryptosporidium parvum: Studies in

Gnotobiotic Pigs. The Ohio State

University.

PCR Based Detection of cytopathogenic

and Non-Cytopathogenic Viruses in

Water. University of Arizona.

Norwalk Virus-Like-Particles (VLPs) for

Studying Natural Groundwater

Disinfection. University of California

Irvine; Baylor College of Medicine.

Studies of the Infectivity of Norwalk and

Norwalk-Like Viruses. University of

North Carolina at Chapel Hill.

In Situ Assessment of the Transport and

Microbial Consumption of Oxygen in

Groundwater. New York State

Department of Health.

Reversible Inactivation of Viruses in

Groundwater. El Paso Community

College; Texas A&M

Direct Quantitation of Haloacetic Acids

by Surface Enhanced Raman Scattering.

Pennsylvania State University.

Combined Ozonation and Biological

Treatment for the Removal of Humic

Substances from Drinking Waters.

Michigan State University.

Investigation and Optimization of Dual

Coagulation Processes., University of

Washington.

Evaluation of the Efficacy of a New

Secondary Disinfectant Formulation

Using Hydrogen Peroxide and Silver and

the Formulation of Disinfection ByProducts Resulting from Interactions

with Conventional Disinfectants.

University of Michigan.

Health Risk of the Trihalomethanes

Found in Drinking Water: Carcinogenic

Activity and Interactions. Medical

College of Ohio.

Analysis of Organic By-Products from

the Use of Ozone / Chlorine and Ozone

/ Chloramines in Drinking Water

Treatment. University of Massachusetts.

Development of a New, Simple,

Innovative Procedure for the Analysis of

Bromate and Other Oxy-Halides at Sub

ppb Levels in Drinking Water.

University of North Carolina at

Chapel Hill.

Inhalation and Dermal Exposure to

Disinfection By-Products of Chlorinated

Drinking Water. University of

Medicine and Dentistry of New

Jersey.

Evaluate the Disposition, Toxicokinetics

and Metabolism of Selected Haloacids

on Fischer 344 Rats and B63F1 Mice

and Investigate the Effect of Chronic

Exposure and co-Administration of

Haloacids on Toxicokinetics. Pacific

Northwest National Laboratories.

Development of Biomarkers for

Haloacetonitriles: Induced Cell Injury in

Peripheral Blood. The University of

Texas Medical Branch.

Genotoxicity and Occurrence

Assessment of disinfection By-Product

(DBP) Mixtures in Drinking Water.

University of Illinois at Urbana.

Metabolic Fate of Halogenated

disinfection By-Products In-Vivo, and

Relation to Biological Activity.

University of North Carolina at

Chapel Hill.

The Microbial Transformations of

Arsenic in Anoxic Waters. Princeton

University.

Arsenic removal by Softening and

Coagulation. University of ColoradoBoulder.

Detecting Fecal Contamination and Its

Sources in Water and Watersheds.

University of North Carolina.

Public Opinion on Environment and

Water Quality Management in the New

York City Watershed. Cornell

University.

Aluminum Toxicokinetics: Oral

Absorption from Drinking Water and

Brain Retention. University of

Kentucky Research Foundation.