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November 7, 2005

Grad student honored for work on trace metal contaminants in San Francisco Bay

By Emily Saarman

Allison Luengen grew up peering under docks at the many strange and wonderful creatures that inhabit Puget Sound.

Allison Luengen
Since coming to UCSC in 1998, Allison Luengen has been studying trace metal contaminants in San Francisco Bay.
Photo: Tim Stephens

The daughter of a marina manager, Luengen loved the underwater world, but she also understood why people sometimes resisted environmental regulations intended to protect that world. Her father often felt the regulations that affected him were not backed by sufficient science, she said.

"He would say, 'If I knew for sure it mattered, I wouldn't mind making the changes,'" she said.

Now, as a graduate student in environmental toxicology, Luengen is doing just the kind of science that is needed to back up environmental policy. Since coming to UCSC in 1998, she has been studying trace metal contaminants in San Francisco Bay. Earlier this year, she received the Outstanding Student Achievement Award from the Department of ocean sciences.

The award recognizes scientific excellence coupled with outstanding community service. In announcing the award, ocean sciences chair Kenneth Bruland noted Luengen's "impeccable academic credentials," commitment to addressing environmental problems, and public service.

"She epitomizes the aims of the Ocean Sciences award," Bruland said.

Working with Russell Flegal, professor of environmental toxicology, Luengen earned a master's degree in marine sciences in 2001 and is now completing her doctoral thesis in environmental toxicology. For her master's thesis, she developed a technique to quantify immune response in mussels and showed that environmental contaminants change that response. Now she is studying how algal blooms in South San Francisco Bay affect the cycling of trace metals such as copper, mercury, and lead.

Trace metal contamination in San Francisco Bay is a serious environmental and health concern. The bay's water and sediments contain elevated levels of several toxic metals, some of which pose threats to humans and wildlife. State health officials have issued advisories warning people not to eat fish from San Francisco Bay because of mercury contamination.

Sources of metal contaminants to the bay include discharge from industry, storm water runoff, and remobilization from sediments. Much of the mercury in the bay is a legacy of historic mining operations in the mountains of California.

Luengen learned about the complexities of environmental contamination in the bay when she worked as a research associate at the San Francisco Estuary Institute. Realizing that research in this area spans a wide range of disciplines, she came to UCSC determined to broaden her range of scientific skills. Her current work incorporates oceanography, geochemistry, and plankton physiology, and she draws on the expertise of scientists in several departments at UCSC, including Bruland and Peter Raimondi, professor and chair of ecology and evolutionary biology.

The story of pollutants in the bay is much more complex than just figuring out how long it takes for contaminated water to flush out of the bay, Luengen said. Blooms of microscopic algae called phytoplankton--and the way these tiny plants use trace metals in their cells--may affect how long toxic metals like lead and mercury stay in the estuary.

Phytoplankton interact with different metals in different ways. Some metals are necessary for algal growth and are readily incorporated into phytoplankton cells or stuck to the outside of the cell surfaces. If the metals are bound to other compounds, they may be unavailable to algal cells. Mercury is not necessary for cell growth, but in the form of methyl mercury it easily slips through cell membranes. Metals that become incorporated in algal cells enter the food chain, where they can build up in fish and shellfish that feed on the algae.

"There is the potential for metals to go into the algae, then through shellfish to fish and on to people," Luengen said.

Luengen's work is part of a larger goal to learn what causes high levels of mercury in fish and whether or not there is anything that can be done to lower these levels, Flegal explained.

Luengen has chosen to study San Francisco Bay because it is a place where humans interact extensively with the marine environment. Not only are estuaries heavily impacted by human activities, an unhealthy estuary affects all the people who live on its shores.

"Estuaries are incredibly fun to study because they're a dynamic interface between land and sea," Luengen said.

Luengen has repeatedly demonstrated her commitment to the community and to promoting the health of San Francisco Bay. At the San Francisco Estuary Institute, scientists were so impressed with her work that she has a standing offer of employment, Flegal said.

But her commitment to public service extends beyond her concerns about San Francisco Bay. Luengen serves as the internal vice president of UCSC's Graduate Student Association. She also teaches an environmental toxicology class for the California State Summer School for Mathematics and Science in which she helps high school students measure contaminants in a local lagoon. She says she enjoys the change of pace and watching the students get excited about marine science. The program, known as COSMOS, brings motivated high school students together with successful scientists to explore their interest in a wide range of scientific topics.

Luengen's scientific achievements and commitment to public service have been widely recognized. She has received prestigious fellowships and earned awards for her presentations at scientific meetings.

"We fully expect Allison to become a leader in the environmental field in the San Francisco Bay Area," Bruland said.


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