Chemistry Of Mercury Is Focus
At sites around the world and at his base lab at the Avery Point campus, marine geochemist William F. Fitzgerald has for more than 30 years conducted research and spread the word about how mercury is cycled in the environment. His work has challenged traditional ideas about mercury’s effects, and has altered the way scientists once sampled aquatic systems for mercury contamination.
Fitzgerald, who was named a Board of Trustees Distinguished Professor last spring, has been called “the father of mercury research.” But a former student, Robert P. Mason, now a professor at Chesapeake Biological Laboratory at the University of Maryland, says he’s actually the “grandfather” – his former students have now graduated their own students who are also researching mercury.
“He’s the world’s foremost expert on the chemistry of mercury from an oceanographic and environmental point of view,” says W. Berry Lyons, director of the Byrd Polar Research Center at Ohio State University and one of Fitzgerald’s first Ph.D. students at UConn in the 1970’s.
Fitzgerald last year won the Clair C. Patterson Medal, the highest award of the Geochemical Society for environmental geochemistry and one that reflects two important influences on his work. It was awarded in Japan, where an industrial disaster first inspired Fitzgerald to study mercury, and it is named for his mentor, whose research on lead pollution resulted in the lead-free standard for gasoline.
Clair Patterson’s clean sampling and laboratory techniques shook up the environmental field when Fitzgerald was a young researcher. At a 1972 National Science Foundation conference at Brookhaven National Laboratory, Patterson “chastised” the marine trace metal community, according to Lyons, for making inaccurate measurements.
“We were trying to measure on a ship – this big piece of metal,” recalls Mason, the Maryland professor. The samples were inevitably contaminated, Fitzgerald said, so he threw out his own data and started from scratch. The University provided the funding for a clean lab at Avery Point, and Fitzgerald’s group developed protocols that are now used worldwide for analyzing and processing mercury and its highly toxic cousin, methyl mercury.
“I worked with Patterson for 20 years. He was the premier environmental chemist in the U.S. and he was my ultimate standard for thoroughness,” says Fitzgerald. In the latest ultra-clean lab at the Marine Sciences Building at Avery Point, a yellow tape on the floor of the anteroom is the point at which street shoes must be abandoned in favor of clean-room attire.
Patterson’s legacy of careful data collection is one that Fitzgerald continued. “It takes a lot of patience to wait to publish until everything is well tested,” he said. “But it’s part of our tradition here, being scrupulous.”
That methodical approach may seem out of character for a man that his former students describe as gregarious, warm and, as Mason says, “so enthusiastic when he’s in the field.”
Fitzgerald has described himself as “somewhat of an Irish Puritan.” He was born and reared in Boston, the son of Irish immigrants. His high school chemistry teacher spurred his interest in science, and he studied chemistry at Boston College and Holy Cross. Then, he recalls, “I wanted to do something adventuresome – to do chemistry, but out in nature.”
He went to Woods Hole Oceanographic Institution in a joint Woods Hole/Massachusetts Institute of Technology graduate program, and found his niche in oceanography. The best part, he says, was that everyone wore Bermuda shorts and sneakers, and “you couldn’t tell who was a boss and who was not.” That’s his typical attire today, an outfit at home in his Avery Point office with its spectacular view of sailboats moored at a marina.
It’s also a style that has set the tone in his research groups, which he calls “Team Hg” after the chemical symbol for mercury.
“He treated us as part of his extended family,” recalls Lyons, the Ohio State researcher.
“That talk affected me in a significant way – I wanted to be able to prevent these tragedies,” Fitzgerald said. He began studying mercury, and since 1970 when he came to UConn as an assistant professor, he has had almost continuous NSF funding to do so.
In the early 1970’s, as environmental studies became popular, “we realized we didn’t know very much about the distribution of these contaminants in the environment,” Fitzgerald says. His research group raised the awareness of the scientific community to mercury’s global polluting capabilities, he says, and he is continuing to add to that awareness, in research on the Long Island Sound and in Arctic lakes in Alaska, among other places.
Mercury is “an incredibly interesting element,” Fitzgerald says. Mercury by itself is not terribly toxic, he says, but when it becomes methyl mercury, which occurs principally in bacterial processes in the sediment of aquatic systems, it is highly toxic.
Most methylation takes place in coastal areas, and most fish consumed by humans come from or frequent coastal areas or consume other fish that do. Methyl mercury moves up the food chain from plankton to alewife to lobster, bluefish, winter flounder, and tuna and binds to the protein in fish, residing in muscles (the fillet).
The recent EPA guidelines on how much fish it is safe to eat and avoid mercury poisoning are very conservative and quite protective, Fitzgerald says. But what happens if they are exceeded? he asks.
“We need to study the coastal zone much more carefully and much more extensively,” he says.
His own research on Long Island Sound is focused on how methyl mercury is created, enhanced, bio-accumulated, and destroyed. It could provide a template for other researchers, offering questions and strategies to use in studying other coastal areas, he says.
Although mercury has been in decline since 1970 in water, with the elimination of careless plant discharges and better sewage methods, “less” is relative. Methyl mercury is created naturally by sulfate-reducing bacteria (the sulfur smell at low tide on the coast attests to this), but industrial discharges have greatly increased it. He estimates that the upper layers of sediment in the Sound contain 25 tons of mercury, or four to six times as much as in the pre-industrial past.
One of Fitzgerald’s latest projects is studying mercury depletion in five remote tundra lakes in Alaska. There, mercury is depleted from the atmosphere and deposited in the lakes. Global warming may be contributing to increased organic matter in the lakes, and this may be leading to less photodecomposition, which has in the past kept methyl mercury production in check.
Even though the systems are diverse – Arctic lakes versus the Long Island Sound – the net production of methyl mercury in the sediment of both places is about 10 percent to 20 percent of the mercury depositing annually, he notes.
As Fitzgerald said in his speech accepting the Patterson Award, there is urgency to his research because of the health concerns that mercury contamination poses, yet “there are more than enough questions for another 30 years of work.” Fitzgerald has just received notice of a new three-year, $400,000 NSF grant to continue his research on mercury cycling in the Arctic.