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Water Security & Waterborne Illness
Part One : Issue Overview

This is a full transcript of the online presentation. For the presentation itself, go here.

Presented by:
Bart Bibler
Bureau Chief, Bureau of Water Programs
Contact Number: 850-245-4241

Dr. Roberta Hammond
Food and Waterborne Disease Coordinator
Contact Number: 850-245-4116

My name is Bart Bibler, I’m the Bureau Chief of Water Programs here at the Florida Department of Health (DOH), and would like to discuss with you water security and waterborne disease.  Water is the single most abundant substance in the human body, and adults should drink about two liters per day.  A person can live several days without food, but just a few days without water.  The water must not contain harmful levels of toxic chemicals or pathogens.  The importance of water to public health makes it a potential target requiring our preparedness.  There are three main types of events that can affect our access to safe water and therefore we must be prepared to protect against.  That includes Unintentional Contamination, Intentional Physical Attack, and Intentional Contamination.

Let’s look at these risks in more depth starting with Unintentional Contamination.  Of the three, this is the most likely kind of contamination.  This could be caused by natural chemicals or pathogens in the source water; chemical contamination from inappropriate residential, commercial or agricultural activities; animal or human waste; or malfunctioning water treatment processes.  In 1993, an Unintentional Contamination event occurred in Milwaukee, Wisconsin.  Cryptosporidium contamination from agricultural animal waste entered the water supply that also had a malfunctioning water treatment filter system.  Four hundred thousand people were made ill, and it killed over one hundred people.  Hundreds and thousand’s were affected by the water contamination, and it was discovered by a pharmacist who noticed an increase in over-the-counter anti-diarrheal drug purchases. 

The second type of concern is that a water system might physically be attacked with intent to destroy its infrastructure.  This could include destruction of the well pumps, the treatment plant, storage tanks or the distribution pipes.

And lastly, a water system might be attacked with a chemical or biological agent intended to harm water system consumers.  The chemical agents might include pesticides, cyanide or nerve agents such as serin.  There are a number of biological agents that are a threat to drinking water and could be used as biological weapons.  These agents may be stable in water.  They may have a high chlorine tolerance, therefore difficult to disinfect.  They can be difficult to filter out.  They can have a low infective dose and so wouldn’t require a large quantity to contaminate the water supply.  And, they may have incubation periods of several days.  They may cause specific diseases, or cause general symptoms such as diarrhea, vomiting or fever.  The severity and mortality would be of greater significance in the sensitive members of the community, including the elderly, the very young and immuno-compromised, and those with underlying disease.  Even a small contamination event could cause widespread fear and concern. 

There are a couple examples of attempted Intentional Contamination in this country that we know of.  In 1984, a cult in Oregon poured salmonella and raw sewage in to a storage tank.  In central Florida, naphthalene (which is used in moth balls and some pesticides) was injected directly into a water distribution system serving several buildings.  So, it can happen. 

Now that we have looked at potential agents of water contamination, let’s look at how such an event could happen.  Systems are vulnerable at four general locations in the treatment process: at the source water, during water treatment, at the storage locations, and in the distribution systems.  Water systems in Florida obtain their water from groundwater aquifers, lakes, rivers, reservoirs and even marine waters.  The water treatment can be simple or complex depending on the quality of the source water.  Most private and very small water systems have no treatment at all, including no disinfection.  Some treatment systems include open tanks, or aeration with screened trickling cascades.  Others are entirely closed systems, sometimes under pressure through membrane filters.  Storage can be supplied either on or off the treatment site in ground or in elevated storage tanks.  The distribution system is under pressure, and is often inter-connected with storage facilities or other water systems.  The distribution system is considered the highest risk for contamination, since no further treatment is applied after this point and the first customers downstream may receive high doses of the contaminant. 

Water treatment systems are regulated and categorized depending on the number of people served by the system.  Water systems that serve over 25 people or 15 service connections are regulated under the Safe Drinking Water Act.  The Department of Environmental Protection (DEP) has primacy from the United States Environmental Protection Agency to implement the Safe Drinking Water Act in Florida.  By interagency agreement, the DOH fully implements the Safe Drinking Water Act in ten of Florida’s largest counties.  The DOH is also responsible for assisting in investigations of complaints related to public water systems and in notification of potentially affected customers.  The DOH has final authority in ensuring that precautionary boil water notices are issued and rescinded.  Water systems that serve less than 25 people or 25 service connections are regulated by the DOH.   These include limited use water systems, mutli-family water systems, and private wells.  Most of these systems do not include disinfection treatment. 

To go over what we’ve discussed, water is at risk for Unintentional Contamination, Intentional Contamination and Intentional Attack on the treatment infrastructure.  Water systems may have four key vulnerabilities for contamination or destruction: at the source, during water treatment, at the storage location, and in the distribution systems.  Of these, the distribution system is often cited as the most vulnerable.  The DEP and the DOH are partners in protection of our water systems.  The water systems are categorized and regulated depending on the number of people that the system serves.  The next presentation will talk in more depth about how water is protected and what can be done to help those efforts.