KING COUNTY – Following new threats of biological or chemical attacks over the past week, the nation’s drinking water supply has come under close scrutiny as concern that water will be the next primary terrorist target grows.

On Oct. 10, water providers across the country joined to ask Congress for $5 billion for increased security and to shore up a deteriorating infrastructure. On Oct. 11, Attorney General John Ashcroft ordered all branches of law enforcement, including local police departments, to highest alert following what he termed “credible, non-specific evidence of imminent attack.”

Major utilities that serve large urban populations top the list of potential targets, including the Seattle-King County drinking water supply that originates from Chester Morse Lake, southeast of Rattlesnake Lake.

“We have increased security significantly,” said Seattle Public Utilities (SPU) spokeswoman Sheila Strehle, “but we are not going to release any specific details regarding new measures.”

SPU currently serves 1.3 million residential and business customers in King County, and sells water wholesale to 25 other purveyors in the region. The treated drinking water is stored in nine reservoirs around the county. Although each receptacle is kept under surveillance, the utility plans to implement a state-approved program to cover the open reservoirs.

Some government officials and public health experts, citing the amount of biological material needed to contaminate a large water source, have expressed doubt that an attack on water supplies would be successful.

“It would take vast quantities of a bacteria to be effective,” said Dr. Jeff Duchin, an infectious disease specialist with Public Health-Seattle and King County. “It would be very difficult logistically.”

Others disagree, arguing that growing sufficient biological agents under laboratory conditions and delivering them to the primary drinking water source undetected may be out of reach for most groups, but a variety of low-tech, unsophisticated means to contaminate large drinking water supplies is cause for great concern.

“We have been working closely with law enforcement since the Sept. 11 attacks,” said Gregg Grunenfelder, Division of Drinking Water director for the Washington State Department of Public Health. “We are receiving regular updates from the FBI National Infrastructure Protection Center.

“The larger utilities systems like Seattle Public Utilities are required to plan and update their response and preparedness directives every six years. Oversight and early detection is an essential element in that process. We were focusing on the potential for contamination of drinking water sources long before Sept. 11. We’re doing the same now, but with a much heightened awareness.”

Although aerosol delivery of a destructive biological or chemical agent has been presented as the most likely – and most effective – means to infect a large population, Grunenfelder, along with other public health experts and government officials, agrees that early detection is the key to preventing a major outbreak of waterborne disease.

Dr. R.E. Hurlbert, a Washington State University microbiologist and long-time educator, used a class project to illustrate the vulnerability of drinking water supplies. Now retired, Hurlbert published results of the project two years ago.

Hurlbert constructed an academic exercise for his microbiology students that included an in-depth examination of the water supply and potential effect of introduction of dangerous microbes in all its aspects, including water treatment, purification, sewage treatment and the water delivery infrastructure. The results of his work showed alarming vulnerability, particularly where aged, deteriorating infrastructure weaknesses were greatest.

“Some systems are more that a century old,” Hurlbert said. “The infrastructure in New York is in a terrible mess with corroded pipelines, valves frozen open for years and constant breakages because lines are not inspected. There is a high danger of a low-tech attack using that weakness. We need to put significant effort into protecting and rebuilding the infrastructure, and we need to make a best effort to strengthen the public health system and protect water and food supplies.”

SPU is also working to protect its infrastructure while improvements are made to the aged system. The utility is using a combination of security staff, intrusion alarms and security arrangements to protect the reservoirs, some of which are 100 years old. Several capital improvement projects are currently in the works to replace deteriorating delivery lines. More upgrades are in the planning and engineering phase, but the process is long and costly.

“The soil-based, naturally occurring contaminants such as E. coli and cryptosporidium are the leading cause of death in countries where the water systems are not well maintained,” Grunenfelder explained. “The contaminations here that do occur are most often from natural causes because of water line breaks and that sort of thing, so while we do monitor very closely, it’s difficult to prepare for such a unique situation as deliberate vandalism or a terrorist attack.”

Successful biological attack by water was employed against Russian troops during World War II. Later incidents have been reported in Cambodia, Laos and Afghanistan. The most recently documented event took place one year ago in Kosovo, where 700 people were affected by the deliberate introduction of tularemia, a nerve agent, into the drinking water supply.

At an Oct. 8 briefing to the Metropolitan King County Council, public health officials focused on the need for better communication between agencies and more training in identifying illnesses associated with the intentional introduction of biological agents for health-care providers.

“We need to do a better job on advanced warning,” said Councilman David Irons. “We could be delayed days, even weeks, identifying a problem and we need to speed that up. I want to see a database of symptoms that can link cases. This can give us a head start of hours or days that could literally save tens of thousands of lives in the event of a biological attack.”

Despite the disagreement between experts regarding the potential effectiveness of introducing a biological agent to a large body of water, the recent mailing of powdered anthrax around the country, as opposed to an anticipated large-scale aerosol contamination attempt, has radically changed conventional thought with regard to biological vulnerabilities. Risk assessment teams are working with utilities to evaluate the potential for attack and secure water supplies, nuclear power plants and food processing sources.

“Everyone must be vigilant, but not panicked,” Irons said, joining a chorus of local, state and national officials. “This is a war where the front lines are you and me – average citizens. We need to be alert to suspicious activity and look out for each other.”