David Putnam, a microbiologist and immunologist, demonstrates
a machine called the coliform analyzer, which rapidly analyzes bacterial
contaminants in water, is simple to operate, and is smaller and lighter than
the normal water-analysis setup. Photo by Karen Fleming-Michael
(Click
photo for screen-resolution image); high-resolution image available.
|
Demonstrated by David Putnam, a microbiologist and immunologist, the machine,
called the coliform analyzer, meets its early goals of rapidly analyzing
bacterial contaminants in water while being simple to operate and smaller and
lighter than the normal water analysis setup.
"The device takes conventional methods and improves on them with electronics
and computers to enhance the entire process," said Thomas Gargan, of Geo-
Centers Inc. at USACEHR, who has provided oversight of the machine's progress
since 2000. "It's simple, straightforward and very innovative."
The shoebox-sized machine, with its blinking colored lights, cuts the weight of
conventional analyzers to eight pounds while providing quick answers on whether
water is contaminated. It also incorporates innovations such as replacing a yo-
yo-sized filter with one that resembles a dime-sized spinning top and borrowing
technology developed by the wine-in-a-box industry for collecting and
dispensing water samples.
Further, the machine provides continuous progress reports for up to eight
samples, which can be run simultaneously, and gives definitive results in eight
hours instead of the 24 hours it normally takes. The machine can be used to
test drinking water, source and surface water, treated water and recreational
areas.
During the demonstration, Putnam used super-contaminated water, so attendees
saw results right away as the machine updated its results.
"In conventional tests, lots of organisms are present and it doesn't matter
which one -- it takes a day to find out. You wouldn't know until tomorrow,"
Putnam said. "The only way to approach it right now is to cover the range and
see what you've got."
His machine looks for the presence of both total coliform bacteria and E.
coli. The presence of E. coli in a water sample indicates the water is
contaminated by fecal matter, and can make drinkers ill.
The procedure is relatively simple, so even people with little training can
prepare samples for testing. The user takes a sample, which can be gathered in
the kit's six-liter wine-box bag, and runs the water through a filter that
grabs particles. The operator then injects the filter's particles into a
special media that encourages only coliforms to grow.
As soon as the sample and media are put in the Coliform Analyzer, the machine
begins reporting what's in the sample.
"Almost immediately, the operator can know if the sample has contaminants that
could pose a danger to drinkers," Gargan said. "And by the end of eight hours,
the operator will know if the sample contains coliforms as well as how many."
Military preventive-medicine specialists routinely work behind the scenes to
sample water in the field to make sure it's fit to drink, said Paul Knechtges
of USACEHR, who manages a program to develop devices to detect contaminants in
water and food. Having a light, portable, rapid analyzer can make their jobs
much easier, he said.
"We trust that when we turn on the tap, we get good water, and 99.9 percent of
the time the (test) results are negative," Knechtges said. "But it's the .01
percent that's going to cause a water-borne disease outbreak. You don't want it
to happen during operations."
The magic of the machine is its ability to measure the fluorescence of the
coliforms that glow under the machine's ultraviolet lights as they multiply in
the media.
The "nifty, golly, gee whiz" part of the device, Gargan said, is that you can
see the real-time growth of bacteria because every two minutes the machine
takes a reading to see what's growing.
The computer systematically counts the number of bacteria -- a chore that's
difficult for most skilled technicians to do under a microscope -- and sends
the results to both a graphing program and the machine's display lights. Red
and yellow lights mean the sample is contaminated with both total coliform
bacteria and E. coli.
"The beauty is that you don't need a computer printout or even the laptop. The
machine will tell you with its lights if a sample is clean or not," Gargan
said.
Military preventive-medicine teams routinely make decisions on which water is
best, and this machine can help them determine which source of water is
cleanest. After serving with disaster-relief missions in the Pacific, Knechtges
said he can see how useful rapid water analysis is.
"There's a saying that in preventive medicine, the better job you do, the more
invisible you become. But in the field you become a VIP," he said. "I used to
have docs and nurses come up to me and ask if the water was all right to drink.
That's a big responsibility."
(Karen Fleming-Michael is a staff writer for the Fort Detrick Standard.)
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