V-/EPA
United States
Environmental Protection
Agency
Municipal Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-81-212 Oct. 1981
Project Summary
A Hazardous Materials
Spill Warning System
Milton Kirsch, Robert Melvold, and John Vrolyk
The U.S. Environmental Protection
Agency (EPA) has developed a list of
materials that, based on their aquatic
toxicity, are defined as hazardous
substances. In addition, certain mate-
rials have been designated as "priority
pollutants." Often, a spill of toxic
materials into a moving water stream
can occur without the knowledge of
the spiller, or without notification of
the authorities, or both. Accordingly,
a system was needed to detect the
presence of hazardous or toxic mate-
rials in streams and rivers. This need
has been filled by providing a spill
alarm system that was designed,
fabricated, and tested before delivery
to the Oil and Hazardous Materials
Spills Branch in Edison, New Jersey.
The system consists of nonselective
components that together detect all
the materials on the designated
hazardous materials list and the
priority pollutants. The warning sys-
tem has been shown to be capable of
detecting a wide variety of hazardous
materials, and untended operation is
possible of a 2-week period.
This Project Summary was devel-
oped by EPA's Municipal Environmen-
tal Research Laboratory, Cincinnati,
OH, to announce key findings of the
research project that is fully docu-
mented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
The report summarized here describes
the design, development, and field
testing of a practical hazardous spill
warning system. The system provides
an effective early warning of a hazardous
material spill and thus facilitates a quick
response.
Under the authority of the Federal
Water Pollution Control Act Amend-
ments of 1972, EPA began the process
of designating 271 materials as haz-
ardous. In addition, 65 groups of com-
pounds were identified as toxic and
formed the Toxic Pollutant List. The
latter list was eventually expanded to
129 items. These chemicals are com-
monly referred to as priority pollutants
because of the frequency of their
occurrence in worldwide water analysis.
The federal program to combat spills,
which was developed as a result of the
1972 amendments, is dominated by
three goals: to prevent, detect, and
contain, remove, and clean up spills.
Rockwell International, under the
sponsorship of the EPA's Oil and
Hazardous Materials Spills Branch in
Edison, New Jersey, undertook a project
to design and develop a warning system
to detect spills of hazardous materials in
natural waterways. The spill alarm
system was designed to advance the
state of the art in spill detection, thus
allowing for a quick mitigating response.
System Description
The entire alarm system is housed in
an air-conditioned, 8.2-m (27-ft) auto-
motive trailer, which allows the system
to be conveniently moved from one site
to another. A submersible pump placed
in the watercourse feeds the instrument
package approximately 38 L/min (10
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gpm) through a 5-cm- (2-in.-) diameter
plastic hose.
The detection components that have
been incorporated into the integrated
system are:
1. pH sensor, Leeds & Northrup*
2. Oxidation-reduction potential,
ORP sensor—Leeds & Northrup
3. Electrical conductivity sensor,
Leeds & Northrup
4. Ultraviolet absorptimeter, Teledyne
5. Total organic carbon analyzer,
TOCA Dohrman
The pH electrodes can detect strong
acids and bases or substances that form
strong acids or bases at levels approxi-
mately 1 pH unit above or below that of
the natural waterway. Weak acids and
bases will also be detected by the pH
electrode, but at higher concentrations.
The ORP electrode was included in
the warning system because of its
usefulness in detecting chemical spills.
But because redox equilibria are often
established slowly, it is difficult to
calculate the precise concentration at
which substances are detectable. The
complexity of the processes that nor-
mally occur in natural water lead to the
measurement of a mixed potential
rather than of a single potential that can
be used to identify individual compounds.
The conductivity detector responds to
water soluble electrolytes. Hazardous
substances that fall into this category
are most salts, weak and strong acids
and bases, and substances that react
with water to form them. The sensitivity
of the sensor to spilled substances
depends on the background conductivity
of the natural water, which is in turn
related directly to total dissolved
(inorganic) solids in the water. For these
reasons, the sensitivity of the detector
must be adjusted relative to the natural
water conductivity. More than 150
hazardous substances are detectable by *
the electrical conductivity increase
produced when they are spilled in
natural water.
The ultraviolet absorption instrument
records the ratio of the sample absorp-
tion at two wavelengths, which are
determined by choice of optical filters.
For the alarm system, a 390-nm
reference wavelength filter and a 230-
nm measuring wavelength filter were
chosen. The sensitivity for detection of
'Mention of trade names or commercial products
does not constitute endorsement or recommenda-
tion for use.
many aromatic organic compounds is
high at the 230-nm measuring wave-
length.
All organic compounds are detectable
by the total organic carbon analyzer.
After removal of the inorganic carbon
compounds, a controlled sample volume
is injected into a high-temperature
furnace where oxygen converts all the
organic carbon into carbon dioxide. The
carbon dioxide is measured in a non-
dispersive infrared unit, and it is related
to the organic content of the original
water sample.
Strip chart recorder channels for each
detection component have built-in
alarm circuits that transmit electrical
signals when certain levels have been
exceeded. The specific response level
for each detector can be preset. When
an alarm condition is reached, the
following sequence of events occurs:
1. A signal light on the control panel
indicates which detector compo-
nent produced the alarm.
2. A solenoid valve is opened for a
selected time to permit collection
of a 3.8-L (1 -gal) sample of water
for later chemical analysis.
3. A telephone dialer system is
actuated and transmits a prere-
corded message to any chosen
telephone station. The designated
telephone receiver has an auto-
matic answering system so that
the alarm message is recorded at
the receiving stations.
4. Recorder chart speeds are increased
to show more detail. After the
spilled material has passed the
sampling point completely, the
alarm lights are automatically
turned off, and after a preset time,
a second relay is energized to
prepare to collect a second water
sample for later analysis.
In the complete report, the alarm
system design and performance specifi-
cations are described in detail. The
description includes the system compo-
nents and their operation, figures
illustrating system design, water flow
diagrams, alarm control circuitry, etc.;
lists of the hazardous materials detect-
able by the alarm system; a list of manu-
facturers of the various components;
operating instructions for the system;
and a summary of the field testing of the
completed alarm system.
System Testing
The alarm system was first tested in
the laboratory. Water was recirculated
from a 208-L(55-gal)drum. Sensitivil
levels of the detectors were determine
by the addition of known quantities c
hazardous substances to the water i
the drum.
The system was then field-tested £
two separate locations. The first tes
was conducted on a simulated nature
waterway located at the Rockwell Intei
national Santa Susana Field Laboratory
This waterway was part of a wastewate
control system within which are severs
ponds where effluents from rockc
firings and other operations can be hel
for cleanup before discharge into th
municipal sewage system. Rocke
engine test firings were preceded an
followed by water purges that carrie
quantities of organic solvents an
hydrocarbon fuels. While sampling th
effluent stream during the test firing of
rocket engine, the alarm system wa
able to detect a petroleum fuel dis
charge.
With the cooperation of the Wate
Quality Section of the Los Angele
County Flood Control District, th
second field test site was located on th
Los Angeles River. At this site, th
ultraviolet absorptimeter was able t
detect a highly ultraviolet-absorbin
material that passed the sampling poin
The completed spill alarm system wa
transferred to the Environmental Emei
gency Response Unit in November 197
for further testing. The alarm syster
was successfully used for emergenc
field response at Pittston, Pennsylvani;
from October 19/1979, to Novembe
16, 1979.
Conclusions and
Recommendations
The warning system has been show
to be capable of detecting a wide variel
of hazardous materials, and untende
operation is possible of a 2-week perioc
Furthermore, the system has bee
designed, fabricated, tested, and foun
to meet specific design criteria:
1. Detection components must b
off-the-shelf items ready for us
with a minimum of modification
2. Detection components must b
rugged enough for remote, ur
tended monitoring.
3. System components must b
resistant to fouling, scaling, etc. t
such a degree that cleaning i
necessary only once every 14 day
or longer.
4. Detection compoaents must re
main sensitive under advers
conditions.
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5. The final system must contain
several detectors capable of sens-
ing wide classes of hazardous
substances.
6. Detection components must not
degrade any of the beneficial uses
of a natural watercourse.
The usefulness of the detection sys-
tem was demonstrated during a field
test on the Los Angeles River, where it
detected a highly ultraviolet-absorbing
material that took more than 40 min to
pass the sampling point.
The warning system should undergo
further field testing under a wide variety
of conditions to clarify improvements
that would permit longer periods of
untended operation. The testing should
be conducted on waterways that differ
in dissolved solids content, temperature,
and frequency of pollution by hazardous
materials.
The full report was submitted in
partial fulfillment of Contract No. 68-
03-2080 by Rockwell International,
Environmental Monitoring & Services
Center, under the sponsorship of the
U.S. Environmental Protection Agency.
Milton Kirsch, Robert Me/void, and John Vrolyk are with Rockwell International,
Newbury Park, CA 91320.
Joseph P. LaFornara was the EPA Project Officer (see below for contact).
The complete report, entitled "A Hazardous Materials Spill Warning System,"
(Order No. PB 82-108 424; 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
For information contact Ira Wilder at:
Oil and Hazardous Materials Spills Branch
Municipal Environmental Research Laboratory—Cincinnati
U.S. Environmental Protection Agency
Edison, NJ 08837
•Ct (JS GOVERNMENT PRINTING OFFICE, 1981 — 559-017/7393
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
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