Tiny Protozoa May Hold Key to World Water Safety
12/9/2010 - Woods Hole Oceanographic Institution - Right now, it looks a little like one of those plastic containers
you might fill with gasoline when your car has run dry.
But Scott Gallager is not headed to the nearest Mobil station.
The Woods Hole
Oceanographic Institution (WHOI) biologist has other, grander plans
for his revolutionary Swimming Behavioral Spectrophotometer (SBS),
which employs one-celled protozoa to detect toxins in water sources.
Not only is he working on streamlining the boxy-looking
contraption—eventually even evolving it into a computer chip—but he
sees it as a tool to potentially “monitor all the drinking water in
“It has a unique utility.”
The SBS has been selected as a 2010 “Better World” technology by the
Association of University Technology Managers, which was recently
published in the association’s Better World Report.
Not bad for a concept the U.S. Department of Defense (DOD) once put
on the back burner for a year and a half before finally funding
Gallager’s idea to detect toxins in water sources using the smallest
of animals, the one-celled protozoa.
Now, SBS may be on the cusp of
providing unprecedented assessment of the world’s water supplies.
The groundbreaking technique works by introducing protozoa into
small chambers with water samples taken from municipal, industrial,
or military water sources and comparing them to control samples.
alteration of the protozoa’s swimming mechanics is a sign that water
conditions have changed and chemical or biological
contaminants—pesticides, industrial chemicals, or biological warfare
agents—may be present.
A camera records the protozoa’s swimming patterns, triggering
software developed by Gallager and his colleagues that interprets
the water’s risk.
The device then relays color-coded, traffic
light-type signals to the user: green (safe); yellow (check the
water further for safety); red (bad or deadly—do not drink the
SBS’s big advantage is that it provides virtually instantaneous
feedback on the water supply’s safety, Gallager says.
“It’s a very
rapid approach to providing a continuous monitoring for the
potential presence of toxins,” he says.
Gallager hatched the plan along with former WHOI colleague Wade
McGillis—now a professor at Columbia University’s Lamont-Doherty
Earth Observatory—while examining the possible effects of climate
change on microscopic plankton.
Their premise was that protozoa,
with their unique methods of propelling themselves through water,
might act as barometers of the health of their local underwater
After the 9/11 attacks in 2001, McGillis told Gallager that the
Defense Department was interested in techniques for monitoring water
supplies. Gallager submitted his protozoa proposal to DOD in 2002;
“I didn’t hear back,” he said. “I literally forgot about it.”
The following year, he received an e-mail from the Defense
Department. “It said, ‘How do you want us to transfer the funds?’ he
recalled. “It was nearly a million dollars.”
Today Gallager is working on his brainchild for both WHOI and Petrel
Biosensors Inc., a private company that has licensed the technology
for further development and commercialization.
The company is
attempting to raise about $2 million to further develop and
fine-tune the SBS.
“Other, existing water tests with this spectrum of activity take
from 24 to 72 hours to generate results and can cost anywhere from
$50 to $250 per test,” says Bob Curtis, Petrel’s chief executive
“We estimate that the SBS will perform real-time biological
testing and provide nearly instant feedback for just $1 or $2 per
Commercial applications for the technology include monitoring of
industrial wastewater discharge, security and quality of drinking
water supplies, and the potential testing of water sources
associated with hydraulic fracturing, or fracking, in the oil and
Curtis says Petrel is developing a range of fully automated sensing
instruments that include desktop, portable, and hand-held units.
company is finalizing a business plan and intends to raise $2
million in investment funding to develop initial SBS systems for
In his WHOI lab, Gallager works to refine and fine-tune the science
responsible for those impressive statistics.
He uses up to three
types of protozoa depending on the project—for example, one type may
be good for fresh water and another for brackish water.
The digital camera records the creatures’ movement at 30 frames a
The software tracks the protozoa’s course in two and three
dimensions and evaluates about 50 features of their paths—showing
almost immediately if the organisms are spiraling out of control or
careening erratically around the tank.
The results are compared to those of the control sample of distilled
water, yielding a statistical analysis that “tells you if toxins are
present,” Gallager says, setting off the red, yellow, or green
Further analyses of the swimming patterns, along with
the water’s acidity levels and other variables, can help scientists
determine the presence of specific kinds of toxins, he says,
including pesticides and heavy metals such as cadmium or mercury.
The system includes controls to prevent the reporting of
false-positive and false-negative results.
The tiny animals “replenish themselves” for long periods, Gallager
says, so he needs to change the protozoa supply only about every two
“It’s not a solved problem yet,” Gallager says of the SBS system.
“It needs a couple of more generations to size down.”
ultimately—after SBS has been streamlined and perfected--he
envisions a worldwide, real-time monitoring network with “four or
five units in every reservoir in the world.”
At any given time, he
says, “Somebody at a central location could be monitoring all
drinking water world wide.”
The Woods Hole Oceanographic Institution is a private, independent
organization in Falmouth, Mass., dedicated to marine research,
engineering, and higher education. Established in 1930 on a
recommendation from the National Academy of Sciences, its primary
mission is to understand the ocean and its interaction with the
Earth as a whole, and to communicate a basic understanding of the
ocean's role in the changing global environment.