Testing for Taint in the Water Supply

December 05 / January 06 By: Leslie Britt Volume 3 Number 6

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In our post-9/11 world, we are all more conscious of America's vulnerability to a terrorist threat. Most Americans are aware of heightened security measures at airports and other public transportation hubs. But what about efforts to protect our critical energy and environment infrastructures such as our water supplies? Just how safe is our drinking water? And how quickly would we know whether our water supply has been tampered with?

Scientists at Sandia have recently begun testing some very sophisticated sensor units that will soon be used to check for toxins and harmful bacteria in our nation's water supplies.

"Our goal is to place these sensors within utility water systems and use them to quickly determine if the water contains harmful bacteria and toxins," says Wayne Einfeld, who heads the Sensor Development Focus Area within Sandia's Water Initiative. "This on-site monitoring approach would replace current utility monitoring systems that require water samples to be sent to laboratories for analysis, which sometimes takes days for results."

Two varieties of the sensor have been developed, one to measure liquid samples and the other to take measurements in the gas phase. Both technologies are based on Sandia's (micro) µChemLab—„, a hand-held chemistry laboratory. The liquid prototype was designed and built at the lab's site in Livermore, Calif., while the gas-phase µChemLab was developed at Sandia in Albuquerque.

One of the most amazing features of these units is just how small they are. The µChemLab, electronics, and sample collector weigh about 25 pounds and fit into a box the size of a small suitcase. The only external parts of the two sensor technologies are water collectors. But the familiar adage "size isn't everything" applies here, too. The briefcase-sized units offer the user analysis systems that begin to rival laboratory-based devices and, as they are further developed, will be able to test and analyze water samples for a wide range of bacteria, toxins and volatile organic compounds.

The liquid µChemLab sensor was originally developed at Sandia as a hand-held, battery operated device intended to be used by first-responders during a bioterrorism incident. The sensor quickly and accurately identifies biotoxins found in water, including the Botulinum toxin, ricin, and through further development can be expanded to detect other toxins produced naturally by algae.
With the help of commercial partners CH2M Hill, a leading U.S. engineering firm, and Tenix, an Australian engineering services company, Sandia is preparing to take the sensor to another level.

Through a Cooperative Research and Development Agreement (CRADA) signed in December 2004, the research team is augmenting the hand-held water sensor so that it can be used in a continuous monitoring fashion: automatically extracting a sample from a water distribution system, performing a routine biotoxin screen and sending the results to a central operator at the water treatment system or facility. The device is currently being tested at the Contra Costa (Calif.) Water Utility, says Jay West, Sandia/California principal investigator. Specifically, the team is testing to determine the steps necessary to identify toxins in drinking water, as well as expanding its capabilities as an autonomous monitor. The device is collecting and analyzing a water sample every 30 minutes and reporting results via a real-time data link to researchers at Sandia.

Einfeld reports that the research team will soon be ready to embark on the second phase of the CRADA, which will involve deploying it to at least half a dozen other utility test sites for further testing and characterization. Commercial partner Tenix should have units available for sale in the next year or so.

In a potential contamination event, there are a lot of unknowns, says Einfeld. "Devices such as these allow you to quickly screen and say, —€˜Okay, we've done a biotoxin screen, and we don't see anything there.' So we can essentially eliminate that category from our list of possibilities."

Water utilities are on the hunt for other microscopic villains, such as E. coli bacteria and Cryptosporidium. Standard analysis techniques for pathogenic bacteria in water involve culturing the bacteria for some extended period of time (usually about 24 hours) and then seeing what grows. It's a time-consuming process. And as Einfeld points out, "The bad news is that when you get the answer, it's probably too late."

The challenge is to speed up the analysis process for pathogenic bacteria in water. The µChemLab offers one potential solution. Just like biotoxins, bacterial and viral species have proteins as part of their structure. Einfeld indicates that you can take the same analysis platform currently being used in the device to detect biotoxins and adapt it in such a way that you can crack open the bacteria, access the bacteria's proteins, and then run those proteins through the µChemLab for analysis.

The task is elusive and involves an array of as-yet unanswered questions regarding how best to pre-concentrate organisms prior to analysis.
Curtis Mowry, Sandia principal investigator for the New Mexico project, says his team is seeking to develop a device that detects trihalomethanes, undesirable byproducts of the chlorination process used to control the bacterial content of water.

"The EPA has regulations for water utilities to monitor for trihalomethanes on a regular schedule," Mowry says. "Currently they have to collect samples and send them to labs for analysis. They get numbers back a few days later. This is a scary thing for us as consumers. The way it's done now, chemists might have measured high levels and there is chance someone has already consumed the water before the results return. Using the µChemLab will provide a way to bring the labs to the site and get results in a more timely manner."

The United States has more than 300,000 public supply water wells, 55,000 utilities, 120,000 transient systems at rest stops or campgrounds, and tens of millions of hydrants.