Water supply security concerns have been discussed at length
in the United States in recent years, but in the past month this debate has
taken on a new sense of urgency. The tragic events of September 11th
highlighted America’s vulnerability to terrorism and spurred an
unprecedented domestic security response. Water treatment facilities were
identified almost immediately as a potential target for further attacks and
were urged by the FBI to implement security measures, most of which are still
in place.
In the short term, the security measures primarily include
increased security patrols and more diligent monitoring for pathogens and
chemical toxins. Long term security will necessitate investment in water
storage, distribution, treatment and monitoring systems and this will create
opportunities for suppliers of the respective equipment. Unfortunately however,
these measures represent a rather feeble defense against any determined
terrorist.
The attacks on the Pentagon and the World Trade Center were
successful despite those facilities being subject to tight security. Metal
detectors and armed guards were obviously no match for a suicidal pilot with a
jet plane, but this was not the type of terrorism they were intended to
prevent. Similarly, the implementation of security measures such as air patrols
of aqueducts and ground patrols at reservoirs is unlikely to prevent a
carefully planned terrorist attack. This is due partly to the scale of the task
involved in patrolling a large water system and partly to the proven
ineffectiveness of conventional security arrangements against an unconventional
threat.
Closely monitoring water in order to catch deliberate
contamination of the supply before the water reaches consumers is also more
difficult than it sounds. No real-time tests exist to detect the agents most
likely to be utilized by terrorists and the expense involved in frequently
applying the laboratory tests that are commercially available is prohibitive.
Turnaround times for laboratory tests can also be slow enough that consumption
of contaminated water may occur before test results are known. While they may
provide reassurance to a worried public, measures such as hiring security
guards and testing samples for detectable toxins are likely to contribute
little towards preventing a successful terrorist attack.
Many large water systems in the U.S. were built more than 50
years ago, when the threat of domestic bioterrorism seemed extremely remote.
These systems were not built with security in mind, yet their size may be their
best defense against deliberate contamination by a terrorist.
San Francisco, for example, receives part of its drinking
water supply from the Crystal Springs Reservoir south of the city. Assuming
perfect dilution, poisoning this reservoir with sufficient hydrogen cyanide to
cause death or debilitation to someone consuming one glass of water would
require over 400,000 metric tonnes of the toxin (according to a U.S. Air Force
estimate of the required concentration).
Many smaller reservoirs exist, to be sure, and some
contaminants can be dangerous in lower concentrations. But even the most
committed terrorist would struggle to obtain and administer the volume of toxin
required to contaminate an entire reservoir or aqueduct.
For this reason, attacks are more likely to focus on very
small systems or small parts of larger systems. While it may be impossible to
poison the entire water supply of San Francisco, it may be conceivable to
poison one tank of treated San Francisco water or the entire system serving a
remote desert truck stop or isolated ski resort. Not only are the volumes of
toxin required more manageable for a terrorist, but security protection may be
weak or nonexistent. In this case, the safety of consumers relies almost entirely
on humble old chlorine.
In most cases, finished water in a tank will not be filtered
again before it reaches the consumer, and even if it is this will be
ineffective in many cases. Residual chlorine in the tank is the most
significant remaining defense against contaminants.
While chlorine may be ineffective against chemical toxins,
there are some biological toxins and pathogens against which it is effective.
Cholera and the botulinum toxin that causes botulism can be inactivated by
chlorine exposure. Other biological agents, however, are resistant to chlorine
and the resistance of others is unknown.
Anthrax spores, for example, are resistant to chlorine and
can remain stable in water for two years. The resistance of other possible
bioterrorism agents such as plague and brucellosis is unknown. Even biological
agents that are not resistant to chlorine can be a threat if terrorists can
infiltrate a treatment plant and deactivate the chlorination system.
While tanks could be vulnerable, pipes downstream from the
treatment plant also are vulnerable. Fortunately the high pressure contained in
pipes makes injecting a contaminant difficult, but the relative lack of
security could make this an easier target than a finished water tank.
Monitoring every accessible pipe continuously is an impossibility for most
water utilities so again we rely primarily on residual chlorine. Ensuring that
manholes are secure and that tanks are covered and locked may be the most
significant measure a water system can take to prevent this danger in the short
term.
In the long term water supply safety cannot be guaranteed,
but at least there are a greater number of options. In the wake of the
September 11th attacks, The Association of Metropolitan Water Agencies
recommended that the EPA budget for security planning be raised from $2.5
million to $155 million next year. They are also seeking an additional $5
billion to upgrade water and wastewater facilities. Some of this money would be
used to improve the EPA’s notification system, which allows information
to be quickly shared by water utilities, law enforcement and emergency response
agencies. Some would be used to establish bioterrorism response plans and to
identify current security weaknesses.
The potential for manufacturers of water treatment and
monitoring equipment to benefit from increased federal funding depends to a
certain degree on which areas are identified as security priorities.
Detection of chemical and biological agents is likely to be
one area of emphasis. Technology already exists to enable detection of some
potential threats, but until now there has been little demand for it in water
monitoring applications. Examples include a gas and water quality monitor
developed by Sandia National Laboratories (operated for the U.S. Department of
Energy) that is capable of real-time detection of some toxic chemicals. In
addition, biotechnology companies such as Cepheid, Inc. of Sunnyvale,
California, have developed fast on-site tests utilizing DNA analysis for
pathogens such as anthrax.
Another potential area for improvement is in the treatment
facility itself, where increased use of ozonation could complement chlorination
to help prevent pathogens from reaching consumers.
Ideally however, the first priority will be simply to improve
security by installing tamper-proof manholes, ensuring water tanks are covered
and locked, and making sure chlorination systems cannot be interfered with.
This may be a relatively simple process for the nation’s 54,000 community
water systems, provided they have adequate funding.
A danger exists, however, that the smaller — and
therefore the most vulnerable — non-community water systems will not
receive funding or sufficient information. Well over 100,000 of these systems
exist in the U.S. and they serve millions of people between them. Smaller
systems are the most susceptible to bioterrorism, yet they will probably
receive the least assistance from the federal government.
Perhaps federal funding should be focused towards these
potential bioterrorism targets rather than expensive aerial patrols over
aqueducts and armed guards at major urban facilities.
This may provide fewer commercial opportunities for water
treatment and monitoring equipment makers, but it will also provide fewer
opportunities for terrorists.
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