An
Invisible Threat
Contaminated ground water can
prove extremely difficult to treat. Dean Abriola’s
research is designing a novel process using simple ingredients. by Laura Ferguson
Back to main story: Shared
Vision
Linda Abriola was clear about one thing from the start: if she came to Tufts,
her lab came too.
This past summer, the new facility opened on the second floor of Anderson Hall.
It goes a long way toward helping Abriola sustain her inquiry into finding
a solution to one of the most elusive ground-water pollution problems—research
that brings together a humble cake-mix ingredient with hydrology.
Abriola’s interest in ground-water contamination began by chance. Just
out of college, she was a project engineer for Procter & Gamble when, upon
putting in a foundation, her team discovered that fatty acid discharge had
seeped into the ground water. At the time, more devastating impacts of toxic
ground-water pollution were making headlines—like those that forced the
evacuation of Love Canal. “Ground-water contamination was a hot new area,” says
Abriola. “People were beginning to realize that the ground wasn’t
the wonderful filter they had thought it was.”
As a graduate student at Princeton, Abriola says she was fortunate to have
an advisor with the vision to suggest she investigate chlorinated solvents—fluids
commonly used in dry-cleaning operations. Companies were (and still are) supposed
to dispose of these solvents, considered potentially carcinogenic at as little
as 5–10 parts per billion, as a regulated hazardous waste, but, unfortunately,
use and disposal of these chemicals commonly resulted in leaks to the environment. “People
just did not understand the danger of these compounds,” says Abriola. “At
one time chlorinated solvents were even used as septic tank cleaners; people
used to actually pour them down their septic tanks. These chemicals are also
used quite widely as auto-parts degreasers. And when they leak into the environment,
it’s a very difficult problem to resolve because the stuff persists.
“It’s like salad dressing,” she continues. “You have
oil and water and they don’t mix. But if you let salad dressing sit for
a while, you’ll see it separate out to its two components. This separation
happens with chlorinated solvents, too. These liquids are heavy and dense and
tend to go straight down when spilled in the ground, penetrating the smallest
crevices. When the chemical encounters ground water, it just keeps moving downward,
so it’s hard to find and extremely hard to remove. I realized the importance
of trying to figure out how to predict where these chemicals would move and
how to get them out of the ground.”
In graduate school, Abriola would go on to develop one of the first mathematical
computer models to predict how deadly chemicals used in dry cleaning disperse
underground.
Today, these contaminants are still extremely difficult to extract. “It
may, in fact, be impossible to remove them 100 percent,” says Abriola. “So
the challenge is: What can we do to make the situation better? How can we cost
effectively do something good for the environment?”
That’s the question she’s been pursuing now for several years.
Specifically, she and her co-workers are developing a technology that involves
injecting what scientists call surfactants—components of detergent—into
the ground. There they solubilize, or adhere to, chlorinated solvents—just
as soap “washes” out grease and dirt.
The surfactants in this case, however, are not those found in detergents but
in cake mixes—they’re edible, biodegradable, and consequently safe
to put into the ground. “We’ve been working with some of these
surfactants for a number of years now,” says Abriola. “We’re
designing processes to inject them in water into the ground and then flush
the zone that is contaminated. We can then extract the fluid that is laden
with these chlorinated solvents.”
While public water supplies are tested now for these chemicals, they remain
a serious problem. It is estimated that in the United States cleanup for chlorinated
solvent sites would run more than a trillion dollars, says Abriola. “Because
people are arguing that the amount of money is going to be too exorbitant,” says
Abriola, “it is now hard to convince them to invest in research. I’m
on national committees that are looking at the cost/benefits for applying innovative
cleanup technologies to these problems; unfortunately, we still don’t
have all the scientific knowledge we need to evaluate this properly.”
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