Tracking Metals

Researcher and Her Team Study Why Villa Park Dam Water Is So Metallic

January 13, 2009

By Russ L. Hudson

Decades of lightly regulated dumping of harmful chemicals has led to research on how to test for toxin accumulation, which in turn has led to a growth industry in companies that specialize in “washing” soil and “cleaning” aquifers, sometimes with heavy equipment and "chemicals."

Tara Kneeshaw, assistant professor of geological sciences, aims her research at untangling what natural decontamination processes work best and cheapest. For example, putting carefully selected chemicals in the soil helps, even though that sounds counterintuitive, says the researcher. The right chemicals feed bacteria that break down contaminants.

Other times, the best thing to do is … nothing.

“Just be patient and let nature work, if it’s already breaking down the bad stuff,” said Kneeshaw, who is focusing her efforts on the Serrano Water District's Villa Park Dam on Santiago Creek. “The goal is to predict the resulting chemistry and how long it will take.”

Iron and manganese at the Villa Park Dam have built up to levels that can exceed acceptable levels (iron to 0.880 milligrams per liter and manganese to 3.4 mg/l), according to water district data. That much iron and manganese can build up and clog plumbing and pumps, stain clothing and dishes, change the taste of food and make water cloudy and foul tasting.

The water district, working with SIONIX Corp. of Irvine, recently reported some success in testing methods to remove enough metals to make the water potable, which could be significant to Villa Park and parts of Orange. Although that is good news, it doesn't answer the basic questions Kneeshaw wants to answer.

“We don’t know yet the source of those metals. It’s likely they’re being dissolved from natural sources, perhaps the surrounding sediments. We don’t know how much they can build up or how far they’ll be transported. How are such factors as vegetation and bacteria in the water and sediment affecting concentrations?

“We need to answer those questions and make predictions,” Kneeshaw said. “What we learn there can have far-reaching effects in determining the best ways to decontaminate water and soil anywhere.”

Her work is a continuation of her research with Texas A & M University and the U.S. Geological Survey at the Norman Landfill, a closed municipal landfill in Norman, Okla. That work helped Kneeshaw, now a Fullerton resident, realize what she wanted in her career.

“I graduated from Albion College in Michigan with a double major, biology and geology. I knew I wanted to use both disciplines, but I wasn’t sure how. After two years working with U.S.G.S. it became clear I wanted to work on real-world problems affecting the environment. I went to Texas A&M, where I finished my Ph.D. earlier this year in geology and geophysics. My dissertation was on contaminated wetland-aquifer systems.

“Cal State Fullerton is a great base for this study. I’m using some of my new faculty start-up money to bring in four students to work with me: Luissa Ivanovici, a geology master‘s student; Thyda Tith, an environmental studies master’s student; and junior geology majors Andrew Corcoran and Marissa Kuhn,” said Kneeshaw, who adds that she and her team have finalized sampling methods and plan to begin on-site and laboratory work this spring.

Kneeshaw's research plan pleases Mike Maston, senior treatment plant operator at Villa Park Dam, who noted that “Santiago Reservoir, also known as Irvine Lake, is only about 2 ½ miles upstream. It doesn’t have these iron and manganese problems. In fact, levels are less than half of Villa Park Dam.”

Maston believes that the source of the iron and manganese is probably the area rocks and soil, “but it seems to concentrate in that dam. It must be going somewhere from there, too, because water tends to percolate down. It could be getting into underground water.

“I’m hoping,” he said, “Tara’s research resolves those questions.”