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Farm and Home Biosecurity
Consumer/General Public and Livestock/Row Crop Producer
Water Supply
Weapons of Mass Destruction (WMD) Prevention Task
Force Information Paper
Summary
Use of toxic industrial chemicals or biological pathogens to poison municipal
water supplies is not credible. Such use, if attempted, would be unlikely to
cause fatalities. Use against a smaller, dedicated water supply (such as a
residence or a business) could succeed, but the number of persons killed,
sickened or otherwise harmed would be small owing to the limited population
served by the supply.
Key Findings
- The quantity of toxic chemical needed to contaminate a municipal water supply
is enormous (from dozens to thousands of tanker car-loads of the chemical
would be needed). Dumping such quantities into a water supply is likely to
attract attention.
- Most biological pathogens will fail to survive in water as a
contaminant owing to the treatment procedures and to pathogen's nutritional
requirements, which cannot be satisfied by the water. Those pathogens that do
survive are associated with dysentery and similar intestinal illnesses, which
are seldom fatal.
- Procedures already in place and used routinely at water treatment
plants guard against contamination from toxic chemicals and biological
pathogens.
- Natural biological processes, evaporation, sunlight, and chemical and
biological degradation will further lessen the impact of any chemical or
biological substance introduced pre-treatment.
- The vulnerability of water to introduction of a toxic chemical or
biological pathogen increases post- treatment, but the population size that
would be affected diminishes as well. A residential water supply, such as a
well, is the most vulnerable target. A water storage tower represents an
attractive target because the water it contains has already been treated,
suggesting enhanced monitoring of such towers and heightened security measures
around these towers would lessen their vulnerability to introduction of a
toxic chemical or biological pathogen.
- A mere 1 to 2% of the total water consumed is used for drinking. The
residual 98 to 99% is used in cooking (where elevated temperature might reduce
the hazard), washing, cooling, and for commercial purposes.
Additional Facts
Quantity of biological pathogen. Biological agents that have been
developed as weapons by various governments were selected based on the capacity
of the agent to cause disease through the inhalational route rather than by
ingestion. Many of these agents can cause disease through ingestion, but are
significant less effective than is the case for inhalation. For example,
Tularemia was included in the US offensive biological weapons program prior to
1969. It is estimated that only 10-50 Tularemia bacteria are required to cause
the respiratory form of the disease. However, it requires 100,000,000 Tularemia
bacteria to cause disease by ingestion of the organism (that is, a
10-million-fold increase).
Stability / Chlorine tolerance of the biological agent. Microorganisms
vary in their stability in water. Anthrax spores are extremely stable in water
(2 years), whereas the agent that causes shigellosis lasts only 2-3 days. The
chlorination process at water treatment facilities inactivates most bacteria and
viruses. However, some organisms are resistant, such as anthrax spores and the
protozoa Cryptosporidium parvum (which caused an epidemic causing several
thousand people to become ill).
Targeting the water source. Most of the stated threats to the water
supply that have been received by the FBI involve the threatened release of a
biological organism or toxin into a reservoir. In order for this to be
successful (i.e., to cause illness or death), a terrorist would have to
overcome the dilution provided by the volume of water in the reservoir. For some
organisms that require high doses to cause illness, producing enough organisms
can become a formidable task. For example, the organism that causes Tularemia
was developed as a biological weapon for aerosol dispersion. The infectious dose
through ingestion is approximately 100,000,000 organisms. The World Health
Organization developed a scenario of a population of 50,000 people, each person
using approximately 400 liters of water per day. Of this volume, a person
consumes half a liter of water per day. At a minimum, the water source would
have to provide 20,000,000 liters of water per day. Assuming even distribution
within the reservoir in this scenario, a terrorist would have to produce 4 x 1015
organisms, which would require a minimum of approximately 1,000 liters
(over 200 gallons) of a heavy suspension of organisms.
Contamination of a water storage tower would require less material to cause
disease and has a greater chance of survival since the water has already been
treated. Enhanced physical security of critical nodes in the network (such as
water storage towers) and maintenance and monitoring of adequate chlorine levels
would reduce this risk.
WMD Prevention Task Force Points of Contact
Douglas L. Anders, Ph.D.
Microbiologist
Hazardous Materials Response Unit
FBI Laboratory Division
Quantico, VA 22135
Office: 703-632-4652
Pager: 888-557-2986
Dean Fetterolf, Ph.D.
Research Scientist
Forensic Sciences Research Unit
FBI Laboratory Division
Quantico, VA 22135
Office: 703-632-4585
Pager: 877-511-7170
Sources
Textbook of Military Medicine: (Part I): Warfare, Weaponry, and the Casualty:
Medical Aspects of Chemical and Biological Warfare (1997). Frederick R.
Sidell, Ernest T. Takafuji, and David R. Franz (Editors). Office of the Surgeon
General, Department of the Army, USA.
Burrows, W.D. and Renner, S.E. (1999). "Biological Warfare Agents as
Threats to Potable Water". Environmental Health Prospectives
107(12):975-984.
Paper No.3: Water Supplies
10-05-2001, Version 1
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