Research Magazine 2006

Protectors of the environment

Scientists fight to save fish, cleanse drinking water and create greener chemical processes

fish kill at Lake Granbury
Through his research on golden algae, biology professor James Grover works to prevent large fish kills like this one at Lake Granbury. Photo: Gary Turner, Brazos River Authority

The opportunity to catch prize-winning  sport fish means big tourist dollars for  Texas.

But what if the fish die off before a hook hits the water? The anglers take their tackle box—and their business—elsewhere.

Faced with large fish kills caused by the toxic algal species Prymnesium parvum, the Texas Parks and Wildlife Department called in a UT Arlington expert, Professor James Grover, for environmentally sound solutions.

Popularly known as “golden algae,” the microscopic species was first noticed in U.S. waters during the 1980s. The species only blooms in waters that are slightly salty and is confined to the Southwest.

“Possibly it was not present in this country before the ’80s, or perhaps it was present but not problematic,” Dr. Grover said. “It’s a little bit hard to pinpoint exactly why the changes occurred.”

However, it is clear that the algae are causing significant problems now, resulting in millions of dollars in economic losses, as the fish kills occur not only in lakes, but in fish hatcheries and fish farms, important players in Texas agribusiness.

Grover and collaborators at Texas A&M, Baylor, UT Austin and the U.S. Geological Survey are particularly interested in understanding what environmental conditions help the algae become abundant and toxic.

“This is a problem in almost all lakes west of I-35,” Grover said. “I think the state would like it if we could discover something that we could just go out, put in the water and solve the problem. That might work in fish hatcheries, where they can treat all incoming waters, but it’s not practical in huge reservoirs. So I don’t think that will happen, but we may find a way to manage it, to make the algae less toxic.

“So far, we know that when the algae become stressed, they become toxic. We may find a way to put in nutrients that cause the algae to grow but that eliminate their toxicity. Or we may find that some crustaceans eat the golden algae. With that kind of biomanipulation, the algae you don’t want are suppressed by other naturally occurring organisms.”

The researchers have discovered that the algae blooms tend to start in small coves at the edge of large reservoirs. “It may be that we can knock down the bloom while it is still confined to the coves,” Grover said.

The possible solutions are many, but the desired result is well-defined: clean water; a pleasant environment; live (and lively) fish; and the continued popularity of Texas lakes.

Safer water to drink

Earth and environmental sciences Associate Professor Karen Johannesson’s research also involves water, but her concerns focus on underground sources of drinking water.

Partly motivated by a doctoral student from Bangladesh and funded by a 36-month, $323,000 grant from the National Science Foundation, Dr. Johannesson is researching problems with arsenic in groundwater flow systems.

Americans tend to associate arsenic with murder plots, but in South Asia, where people drink arsenic-laden waters, the problem is much more immediate.

“We’re working with biogeochemistry here,” Johannesson explained. “We want to understand how arsenic gets mobilized into the water system. We know that bacteria in aquifers essentially ‘breathe’ iron and that their life process changes the chemistry of the water; it can liberate arsenic that is stuck on the surface of the iron.”

Ingesting that arsenic can lead to a long list of fatal diseases. Arsenic is the No. 1 naturally occurring element that causes cancer, especially skin cancer and bladder cancer. It also leads to hyper-pigmentation of the skin, ulcers, gangrene, various infections, kidney disease and liver disease.

“What we want to know is why some aquifers develop high levels of arsenic,” Johannesson said.

“We’re studying the Ganges area of Bangladesh and India. Initially, the wells there were fine, a tremendous improvement over the bacteria-laden surface waters people used to drink. Those waters were responsible for continual outbreaks of disease. So they went to aquifers. It’s fresh water and it tastes good. For a while it was great, but over time you end up leaching arsenic off the iron-filled sediments. Now the aquifers have high levels of arsenic. We need to know why.”

Johannesson and her team are also studying three aquifer systems in the United States: one in South Texas, one in Florida and one in the Baltimore/D.C. area. These systems either have elevated arsenic or exhibit the potential for developing such levels.

“We want to understand how arsenic concentrations evolve through time and identify the processes that lead to high arsenic,” she said. “Then, when we’re developing aquifers, we can identify those that may develop high levels of arsenic and find other sources or better ways to proceed with the development—ways that will prevent the problem.”

Because arsenic in groundwater is so common, Johannesson and her team feel a sense of urgency. Their goal? Clean, safe drinking water as soon as possible.

Friendly chemicals

Chemistry and biochemistry Professor Rasika Dias wants to keep the water—in fact, the entire environment—clean as well. He plans to do so by developing environmentally friendly methods for various chemical processes. He seeks greener routes to polymers, specifically the conducting polymers like polyaniline.

Polymers, both natural and synthetic, form through chemical reactions in which molecules, called monomers, join sequentially, creating a chain. Natural polymers include proteins, starches, cellulose and latex. Synthetic polymers, usually produced on a large scale, include all of the materials commonly called plastics, as well as other well-known materials such as polyesters and polyamides (nylon).

Dr. Dias works with a conducting polymer known as polyaniline. The ability to conduct electricity ranks among its most attractive features. Already, polyaniline compounds have been used to fabricate all-polymer integrated circuits. The professor’s research includes an application in which polyaniline is used in developing sensors and display devices such as LED-based televisions. Polyaniline also shows promise for use in fibers, antistatic and other coatings, films, diodes, batteries, corrosion protection, printed circuit boards and electrochromic windows.

Creating polyaniline is a messy business.

“You have to oxidize aniline to get polyaniline,” Dias said. “In order for aniline to react with oxygen, something has to provide the oxygen.”

The current oxidization method involves using ammonium persulfate in conjunction with a strong mineral acid. “To make one pound of polyaniline—if you use the ammonium persulfate—you produce three pounds of waste,” Dias explained, “and the whole process is created in an acidic medium.”

Not at all environmentally friendly.

“We want to find a solution to this and other similar processes—a better way to create polyaniline.”

Dias’ research looks promising. Working with a molecule that closely relates to an enzyme found in mollusk blood, in which oxygen molecules are carried to cells by a copper-based metal complex (in human blood, oxygen is carried by an iron-based metal complex), the professor has created a molecule that can supply the oxygen necessary to create polyaniline.

“With a small amount of this modified metallo-enzyme as the catalyst, we can cause the oxygen to connect with the aniline (forming the polyaniline), producing only water as a waste product,” he said. “This is a much greener method. We are after cheaper, cleaner ways of tethering things together and making useful new molecules. We learn from nature, and we modify the molecules and processes to accomplish our purposes.”

— Sherry W. Neaves