United States
Environmental Protection
Agency
Health Effects Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S1 -81 -068 Dec. 1981
Project Summary
Study of Chlorine Dioxide and
Its Metabolites in Man
Joseph R. Bianchine, Judith R. Lubbers, Sudha Chauhan, and Judy Miller
To assess the relative safety of
chronically administered chlorine
water disinfectants in man, a control-
led study was undertaken. The study
was conducted in three phases. Phase
I, a rising, single dose tolerance
investigation examined the effects of
chlorine disinfectants in normal
healthy adult male volunteers. Phase II
considered the effect on normal sub-
jects of daily ingestion of disinfectants
at a concentration of 5 mg/L over a
12 week period. In phase III, chlorite,
at a concentration of 5 mg/L, was
administered daily to a limited number
(3) of gIucose-6 -phosphate
dehydrogenase (G-6-PO) deficient
subjects. Physiological impact was
assessed by evaluation of a large
battery of qualitative and quantitative
tests.
In general, the study affirmed the
relative safety and tolerance of normal
healthy adult males and normal
healthy adult male G-6-PD deficient
individuals to the daily ingestion of 2.5
mg of chlorite for a 12 week period.
This Project Summary was develop-
ed by EPA's Health Effects Research
Laboratory, Cincinnati, OH, to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
Chlorine dioxide (CIO2J has been
identified as a potential water disinfect-
ant alternative to chlorination. A three-
phase human investigation was
undertaken to assess the safety of ClOa
and its metabolites.
In Phase I. Rising-Dose Tolerance
Study, a controlled double-blind study
was initiated to assess the safety of
single dose administration of CI02
and its metabolites over a broad range of
concentrations. Normal healthy adult
males were treated with successive
increasing doses of chlorine dioxide,
chlorite, chlorate, chloramine, chlorine
or untreated water (control). The
concentration ranges examined were as
follows: chlorine dioxide, 0.1 to 24.0
ppm; chlorite, 0.01 to 12.0 ppm;
chlorate, 0.01 to 1 2.0 ppm; chloramine,
0.01 to 24.0 ppm; and chlorine, 0.01 to
24.0 ppm
In Phase II: Chronic Administration to
Normal Subjects. Sixty volunteers were
divided, at random, into six double-blind
treatment groups of 10 subjects each
for the administration of CIO2, CI02
metabolites, chlorite (CIC)2~) and
chlorate (ClOs"); chloramine (NH2CI);
chlorine; and control, distilled water.
The 20-week protocol involved a 12
week period of daily oral administration
of 500 mL of treated water followed by
an 8-week observation period. The con-
centration of water disinfectants was 5
mg/L. Urine and blood samples col-
lected at weekly intervals were sub-
jected to complete routine clinical
analysis and to special determinations
for methemoglobm, glutathione, G-6-
PD and thyroid function. Subjective
evaluation of the qualitative clinical
tests was coupled with the statistical
evaluation of all quantitative chemical
parameters.
In Phase III. Chronic Administration to
G-6-PD Deficient Subjects. Three
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healthy male volunteers found to be
deficient in G-6-PD were chosen for the
study. All three subjects ingested
chlorite; no concurrent control study
was performed The study protocol was
identical to that of Phase II in temporal
design and evaluatipn procedures.
Volunteers received 500 ml_ daily of
sodium chlorite at a concentration of 5
mg/L chlorite.
Materials and Methods
Subject Selection
Normal healthy adult male volunteers
selected for inclusion in this study were
required to satisfy the following criteria:
1. Subjects were between 21 and
45 years of age and were not
confined to an institution.
2. Subjects had no significant
abnormal physical findings at the
pretreatment physical examina-
tion.
3. Subj'ects had no laboratory values
significantly outside the normal
range at the pretreatment evalua-
tion.
4. Subjects weighed at the time of
the pretreatment evaluation
within ± 10% of the normal body
weight for their frame and stature
based on a standard weight table.
5. All subjects gave written consent
to participate in the study.
Subjects were excluded from the study
if they.
1. Had symptoms of significant
clinical illness in the two weeks
preceding the study;
2. received any drugs in the four
weeks preceding the initiation of
this study;
3. required any concomitant medi-
cation;
4. had one or more surgical or
medical condition which might
interfere with the absorption,
metabolism or excretion of sub-
stances by the body;
5. -had a known hypersensitivity to
drugs, food or environmental
factors;
6. had a history of cardiac, renal,
hepatic, neurologic, hematologic
or gastrointestinal disease; and
7. had a history of drug addiction
For Phase III, volunteers were defined
as G-6-PD deficient on the basis of a
hemoglobin G-6-PD level of less than
5.0 IU/GM hemoglobin in the pre-study
screening. Phase III subjects were
normal in all other respects
No subject who entered this study
was undergoing concurrent drug
therapy. However, once on study, a
record was kept of the occasional
episode of any physician-administered
drug therapy that was required because
of intercurrent illness. No subject was
dropped from the study because of any
intercurrent illness that developed
during this study.
Discussion
During the course of the three phase
study, a massive volume of raw data
was acquired. For each of the partici-
pants, subjective information was
collected at regular intervals concern-
ing general medical well-being. The
interpretation of physical examinations,
electrocardiograms. Coombs tests, and
hemoglobin electrophoresis increased
the amount of available information
Vital signs (blood pressure, heart rate,
body temperature and respiratory rate)
for each study subject were determined
and compiled. Qualitative examinations
of individual blood and urine samples
were made. Further, 47 quantitative
chemical parameters derived from the
extensive battery of blood and urine
testing procedures were recorded
regularly. The conclusions drawn in this
report were drawn from this body of
information.
The incidence of minor illnesses,
such as "colds" and the "flu" were
evenly distributed among treatment
groups and control groups. Physical
examinations revealed no treatment-
related pathology. Coombs test results
were consistently normal throughout
the study for the treatment groups and
the control groups. The incidence of
borderline abnormal hemoglobin
electrophoresis was greatest during the
posttreatment observation period; no
relationship between treatment and the
presence of abnormal, hemoglobin
electrophoresis could be established.
Examination of individual vital sign
parameters and statistical evaluation of
those parameters failed to identify any
changes in vital signs which could be
attributed to treatment with any of the
water disinfectants. Abnormalities in
the qualitative blood and urine analyses
were few and, again, appeared to be
randomly distributed.
Conclusion
All three phases of this large control-
led and double blinded clinical evalua-
tion of ClOaand its potential metabolites
m human male volunteer subjects were
completed uneventfully, There were no
obvious undesirable clinical sequellae
noted by any of the participating sub-
jects or the observing medical team. In
several cases statistically significant
trends in certain biochemical or physio-
logical parameters were associated
with treatment; however, none of these
trends were judged to have physiolog-
ical consequence. One cannot rule out
the possibility that, over a longer treat-
ment period, these trends might indeed
achieve clinical importance. However,
within the limits of the study, the rela-
tive safety of orgal ingestion of ClC^and
its metabolites, chlorite and chlorate,
was demonstrated.
Recommendations
This study was limited in some
respects:
1. Only male volunteers partici-
pated.
2. Treatment was limited to 12
weeks
3. The number of G-6-PD deficient
subjects was very small.
4 The dose of disinfectants was
fairly low.
With this in mind, we make several
recommendations. In use of chlorine
dioxide as a water disinfectant, the
entire population will ingest the disin-
fectant and its byproducts over a long
period of time. The safety of ingestion in
women and children must be assessed.
The length of study should be increased.
Furthermore, on the basis of Phase III,
the absence of detrimental effects on
potentially susceptible individuals
cannot be ascertained with confidence;
the sample size was limited and no
concurrent control was run. If chlorine
dioxide is to be used as a primary disin-
fectant, human invegtigations at
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increased dose levels ought to be con-
ducted.
Supplementary information including
computer printouts, tables, figures, vital
sign tabulations, subject histories, and
clinical/chemical parameters are on file
at the Health Effects Research Labora-
tory, Cincinnati, Ohio.
Joseph Ft. Bianchine, Judith Ft. Lubbers. Sudha Chauhan, and Judy Miller are
with the Department of Pharmacology, Ohio State University,
Columbus, OH 43210.
Richard Bull is the EPA Project Officer (see below).
The complete report, entitled "Study of Chlorine Dioxide and Its Metabolites in
Man." (Order No. PB 82-109 356: Cost: $9.50, subject to change) will be
available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Health Effects Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
ti US GOVERNMENT PRINTING OFFICE 1981—559-017/7403
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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