United States
Environmental Protection
Agency
Environmental Research
Laboratory
Gulf Breeze FL 32561
Research and Development
EPA-600/S4-81-010 May 1981
Project Summary
Reaction Products from the
Chlorination of Seawater
James H. Carpenter, Carroll A. Smith and Rodney J. Zika
A general study of the reaction
products from the chlorination of
seawater is reported. The results
include the following:
Some analytical methods in wide-
spread current use underestimate the
residual oxidants in chlorinated sea-
water by as much as 70% depending
upon the detail of the procedures.
The chlorination of seawater in the
presence of light produces substantial
quantities of bromate ions which can
influence standard analytical proce-
dures and represents an unknown
factor in estuarine and coastal waters.
The toxicity of bromate ion and the
possibility of bromate as a persistent
source of brominated compounds in
coastal waters needs to be determined.
The copper complexing capacity of
Biscayne Bay, Florida water was found
to be substantially reduced with the
addition of chlorine. Analysis was
made by anodic stripping voltammetry
on water samples after successive
additions of copper sulfate solution.
The chlorination of seawater may,
therefore, produce toxicity and growth
reduction through the indirect mech-
anism of copper release and/or re-
duced binding capacity.
Laboratory chlorination of water
from the intake of the Port Everglades,
Florida power plant produces bromo-
form levels comparable to that found
in the plant discharge. These results
are in contrast to results reported in
the literature for a power plant on the
Patuxent estuary in Maryland, so that
bromoform production appears to be
site-specific.
Chloroform extracts of chlorinated
Biscayne Bay water are found to
contain halogenated compounds which
are new and different, and which pose
unusual analytical problems. Studies
using GC/ECD. GC/MS, HPLC, 1H
NMR, differential pulsed polarography
and other techniques on natural
extracts and synthesized compounds
are reported.
This Project Summary was developed
by EPA's Environmental Research Lab.
Gulf Breeze, Florida, 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
Measurement of residual chlorine in
seawater has been a recent subject of
study with the increasing recognition of
the responses of aquatic organisms to
low levels of "residual chlorine" (1,2).
Measurement of the residual oxidants
in the waters discharge from wastewater
treatment plants and electricity-gener-
ating plants has become important in
order that the environmental impact of
the discharges can be properly assessed
and regulated. The large number of
power plants has led to much greater
input of chlorinated waters. The waste-
water collection systems of many coastal
communities contain some seawater as
a result of infiltration with brackish
ground waters, and chlorine added as a
disinfectant during treatment reacts
with the seawater constituents during
treatment and in the receiving water.
We find that the analytical methods in
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widespread current use can underesti-
mate the residual oxidants in chlorinated
seawater by as much as 70%, depending
on the details of the analytical proce-
dures.
The addition of chlorine to waters
containing sea salts leads to reaction
with the natural bromide ion (65 mg/L
in ocean water) to produce a mixture of
hypobromous acid and hypobromite ion
at pH 8 (3). If ammonia is present, a
mixture of monobromamine and mono-
chloramine may be formed (4). In addi-
tion, reaction with organic compounds
may produce a variety of brominated
substances. Thus, the determination of
"residual chlorine" actually corresponds
to the estimation of the sum of this
complex mixture and is better termed
"chlorine-produced oxidant determina-
tion."
A general study of the reaction
products from the chlorination of sea-
water was carried out with special
emphasis on waters in the Florida
Current and in Biscayne Bay, Florida.
The study extended to several critical
aspects of the chemistry of the chlorina-
tion of seawater. Analytical procedures
for the determination of "residual
oxidants" in chlorinated seawater were
examined critically (5). The chemistry of
hypobromous acid-hypobromous ion in
seawater was investigated with the
finding of bromate formation in sunlight
(6). The copper complexing capacity of
the organic fraction of seawater and the
effects of chlorination on it were investi-
gated by anodic stripping voltammetry
(7). A local conventional power plant
was examined for the production of
bromoform with chlorination and the
persistence of residual oxidants were
compared with other investigators (7).
Chloroform-soluble halogenated com-
pounds were extracted from chlorinated
Biscayne Bay water and examined with
a variety of chemical techniques, in-
cluding GC/ECD, GC/MS, HPLC, NMR
and fluorescence (8).
Results
The results and conclusions resulting
from this study are summarized as
follows:
1) Analytical methods for the deter-
mination of "residual chlorine" (more
correctly termed "residual oxidants")
developed for fresh water use cannot be
applied to saline waters without critical
examination.
2) Some analytical methods in wide-
spread current use underestimate the
residual oxidants in chlorinated sea-
water by as much as 70% depending
upon the details of the procedures. A
technique is described that is shown to
be applicable to seawater.
3) The chlorination of seawater in the
presence of light produces substantial
quantities of bromate ions which can
influence standard analytical procedures
and represent an unknown factor in
estuarine and coastal waters (Figure 1).
The toxicity of bromate ion and the
possibility of bromate as a persistent
source of brominated compounds in
coastal waters needs to be determined.
700
2 80
•S 60
£
40
I 20
J 2 3
Time (hr)
Figure 1. (A) Disappearance of
residual oxidants with
time and (Bj concomitant
appearance of bromate in
chlorinated seawater (4.2
to 4.9 ppm of C/2) as a
function of exposure to
sunlight. The conditions
were: (curve aj full midday
sunlight, fcurve b) 65 per-
cent of full sunlight, and
(curve c) overcast, 20 per-
cent of full sunlight. Curve
d shows residual-oxidant
disappearance in the dark
at 40°C. No bromate pro-
duction was observed in
the dark.
4) The copper-complexing capacity of
Biscayne Bay (Florida) water was found
to be substantially reduced by the addi-
tion of chlorine (Figures 2 and 3)
Analysis of water samples after succes-
sive additions of copper sulfate solution
was made by anodic stripping voltam-
metry. The chlorination of seawater
may, therefore, produce toxicity and
growth reduction through the indirect
mechanism of copper release or reduced
organic binding capacity for copper ion
or both.
5) Laboratory chlorination of water
from the intake of the Port Everglades
(Florida) power plant produces bromo-
form levels comparable to that found in
the plant discharge. Bromoform was
found in the plant discharge in contrast
to the observation by others of the
absence of bromoform at the Chalk
Point power plant on the Patuxent
estuary in Maryland.
6) Chloroform extracts of chlorinated
Biscayne Bay water were found to
contain halogenated compounds, pri-
marily brominated, that could be resolved
by gas chromatography (Figure 4).
Bromoform at 3.7 min overlaps another
smaller peak at 3.8 min. The peak at 2.7
300
200
5
I
I.
;oo
10
Cu Cone ppb
20
Figure 2.
Anodic stripping current
variation with copper
added to a sample of
Biscayne Bay water,
showing copper-com-
plexing capacity of 6 ppb.
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300
0
Figure 3
10
Cu Cone ppb
Anodic stripping current
variation with copper
added to a chlorinated
(5 ppm Cl2) sample of
Biscayne Bay water,
showing a loss of com-
plexity capacity.
min gave a mass spectrum that corre-
sponds to methylisobutyl ketone. Other
peaks that were large enough to provide
adequate mass spectral signals were all
halogenated compounds, as shown by
the characteristic M, M+2 couplets in
the mass spectra. Compounds repre-
sented by the two major peaks at 4.2
min and 5.9 min were studied further,
due to their high abundance in the
chloroform extracts of Bay water, which
may be expected to contain the lipophilic
halogenated compounds that are poten-
tially subject to substantial bioaccumu-
lation. Studies using GC/ECD, GC/MS,
HPLC, 1H NMR, differential pulse polar-
ography and other techniques were
carried out on the natural extracts, as
well as on synthesized compounds that
gave the same mass spectra as the
natural compounds. Work to date,
described in detail in the project report,
has led to partial characterization of
these previously undetected and unknown
chlorination products. The compounds
were found to be reactive with the
reductant, sodium thiosulfate, added to
Bay water at pH 8 and therefore probably
represent a significant part of the
"chlorine-producted oxidants." Since
Tl
' 5 ' '10
Figure 4. Total ion chromatogram of chloroform extract of chlorinated Biscayne
Bay water, total ion abundance vs. elution time, minutes.
such oxidants commonly are biologically
active, the tentative inference can be
made that these compounds, which
were discovered in this study, may play
a substantial role in the environmental
impact from the introduction of chlorine
into brackish and marine waters.
Recommendations
1) Determine the uptake of com-
pounds found to result from the chlori-
nation of seawater, using standard test
organisms and other controlled-expo-
sure facilities.
2) Develop techniques for determin-
ing an appropriately selected series of
haloamines in seawater at trace levels
and examine chlorinated coastal waters
for these compounds, using HPLC with
fluorescence detection at sub-picomolar
levels.
3) Utilize polarography (e.g., differen-
tial pulse, in conjunction with HPLC/
fluorescence measurements), to deter-
mined electroreducible compounds in
natural saline waters before and after
chlorination.
4) Study the formation, decomposition
and reactivity kinetics of haloamines,
utilizing sophisticated stop-flow reaction
techniques. New instrumentation that
makes such work feasible has recently
been developed by collaboration of our
staff with Tracer Northern Inc. and
Update Instrument Inc. Complete UV-
visible-near IR spectra can be measured
at 5 millisecond intervals, so that rapid
reactions and observations of fleeting
intermediates can be followed. Low
concentrations of reactants can be used
because of the signal-averaging capa-
bilities of the system; for example, 200
spectra can be measured over a time
period of one second and these data
averaged. Freeze-quench and continu-
ous flow modes are also features of this
new instrument and may be particularly
useful for the study of haloamines.
5) Study the reactivity of haloamines
with other substrates in living organisms
in vitro and in vivo. Mutagenesis is of
particular concern and can be explored
with the Ames test. Coupling reactions
with RNA would be particularly interest-
ing and could be sought by using C-14
tagged amines.
References
1. Brungs, W.A. Effects of Residual
Chlorine on Aquatic Life. Journal
Water Poll. Control Fed., 45: 2180-
2193, 1973.
» U& OOTBWMENTPHIimNO OFFICE: 1MI-757-012/70W
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2. Water Chlorination, Environmental
Impact and Health Effects. Vol. 1,
R.L. Jolley, ed., Ann Arbor Science
Pub., Ann Arbor, Ml, 1978.
3. Farkas, L, M. Lewis and R. Bloch.
Reaction Between Hypochlorite and
Bromides. J. Am. Chem. Soc., 71,
1988-1991, 1949.
4. Inman, G.W., Jr. and J.D. Johnson.
The Effect of Ammonia Concentra-
tion on the Chemistry of Chlorinated
Sea Water. Water Chlorination Envi-
ronmental Impact and Health Effects,
Vol. 2, R.L. Jolley, H. Gorchev and
P.H. Hamilton, Jr., eds., Ann Arbor
Science Publishers, Inc., Ann Arbor,
Ml, 1978.
5. Carpenter, J.H., C.A. Moore and D.L.
Macalady. Errors in the Determina-
tion of Residual Oxidants in Chlori-
nated Seawater. Environ. Sci.
Technol., //: 992-994, 1977.
6. Macalady, D.L., J.H. Carpenter and
C.A. Moore. Sunlight-Induced Bro-
mate Formation in Chlorinated Sea-
water. Science, 195: 1335-1337,
1977.
7. Carpenter, J.H. and C.A. Smith.
Reactions in Chlorinated Seawater.
Water Chlorination, Environmental
Impact and Health Effects, Vol. 2,
R.L. Jolley, H. Gorchev and P.H.
Hamilton, Jr., eds., Ann Arbor Science
Publishers, Inc., Ann Arbor, Ml,
1978.
8. Carpenter, J.H., C.A. Smith and R.G.
Zika. Reaction Products from the
Chlorination of Seawater. Water
Chlorination, Environmental Impact
and Health Effects, Vol. 3, R.L Jolley,
W.A. Brungs and R.B. Cumming,
eds., Ann Arbor Science Publishers,
Inc., Ann Arbor, Ml, 1980.
James H. Carpenter. Carroll A. Smith, and Rodney G. Zika are with the University
of Miami, Rosenstiel School of Marine and Atmospheric Science, Miami, FL
33149.
W. P. Davis is the EPA Project Officer (see below).
The complete report, entitled "Reaction Products from the Chlorination of
Seawater." (Order No. PB 81-172 280; Cost: $8.00, 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:
Environmental Research Laboratory
U.S. Environmental Protection Agency
Gulf Breeze, FL 32561
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
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Protection
Agency
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