• Civil and environmental engineering senior James Vanzo draws water samples from Lake Pontchartrain, which borders New Orleans, during spring break. Vanzo was one of eight undergraduates who conducted research on water quality as part of Laboratory Course 1.107.

    Photo / Margaret Avener

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  • Junior Margaret Avener and Associate Professor Martin Polz count colonies of E. coli in a culture. The two were preparing for their spring break trip to New Orleans to test water there.

    Photo / Donna Coveney

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Engineering solutions in Louisiana

Students spend break studying lake sediment

Eight civil and environmental engineering undergraduates in Laboratory Course 1.107 spent their spring break on Lake Pontchartrain in hurricane-ravaged Louisiana doing research that may eventually contribute to minimizing the health effects of Hurricane Katrina and other disasters like it.

After Katrina struck New Orleans on Aug. 29, several sections of the levee system collapsed, flooding more than 80 percent of the city. The city pumped much of the floodwater into Lake Ponchartrain, which borders the city on the north.  

The MIT students traveled to New Orleans to study the lake's sediment. They were accompanied by Associate Professor Martin Polz, Professor Heidi Nepf of civil and environmental engineering (CEE) and lecturer Sheila Frankel, research associate and associate director of the Ralph M. Parsons Laboratory. 

Teaching assistant Dana Hunt, a Parsons graduate student, and three former members of Frankel's TREX field research program also accompanied the group. The students' travel and living expenses were paid for by a grant from the Kurtz Family Foundation given to the MIT President's Office for Hurricane Katrina relief.

The MIT students stayed at Southeastern Louisiana University (SLU) for the week collecting sediment and water samples as well as background chemistry measurements and E. coli counts. The samples were sent back to MIT where they will be studied for traces of heavy metals and pathogenic bacteria.

These bacteria, specifically E. coli and Vibrio, a family of bacteria that includes cholera, can be dangerous to humans. "Most seafood-related deaths are Vibrio," Polz said.

Bacteria are typically present in sediment, but large wind events can disturb the sediment, causing the bacteria to seep into the water supply. "There were reports of (Vibrio-related) deaths," Polz said. 

Unfortunately, not much biological analysis was available from before the storm, Polz said. Without data from before Katrina, it is hard to ascertain what is "normal," he said.

The MIT students specifically sampled areas differentially affected by the hurricane, thus their work may help to provide some of the base for future work and monitoring of the lake. Moreover, their work integrates with a National Science Foundation-funded study, which Polz is part of, studying the effect of Hurricane Katrina on the lake ecosystem.

Samples have been collected since mid-September, and this data did provide the students with some foundation for their work, said Frankel.

The students spent the first half of their semester studying the lake and surrounding region. Nepf lectured on the lake physics and ways to calculate how long the water had been in the lake. She also helped the students to measure sediments.

Polz discussed aquatic microbiology and led the investigation of Vibrio presence in the lake. Frankel and Philip Gschwend, CEE associate department head and director of the Parsons lab, lectured the students on aquatic chemistry and Frankel supervised the collection and analysis of sediments for trace metals, particularly lead and chromium.

Stormwater drainage from New Orleans has been pumped into the lake for more than a century and these toxic metals are the legacy of this drainage, Frankel said.

The students learned how to plan a field experiment. They researched previous studies and mapped the lake and created their own research plan. "It was very different to plan our own project," said Lindsay Sheehan, a junior CEE major. "I had the biggest grin on my face the whole time we were on the boats because we were finally doing what we had planned for half the semester."

"It was really amazing to see how the stuff we study in class is done in the real world," said junior Tasneem Hussam of CEE.

The students worked alongside graduate-level researchers at Louisiana State University (LSU) and SLU. SLU Professor Gary Childers and Chris Schultz, graduate student and research associate, helped out, lending use of their facilities and boats. "We felt like we were part of a big Southern family," Frankel said. "Everyone was so wonderful to us."

All told, the students collected 43 sediment samples and 100 bacterial cultures that they packed in dry ice and shipped back to MIT. The students will spend the second half of their semester in labs analyzing and studying their findings.

They will present their results during a Parsons Lab aquatic sciences seminar on Wednesday, May 17. "The students will also communicate their results to our Louisiana partners," Frankel said.

For more information, visit web.mit.edu/parsonslab/newor/index.html.

A version of this article appeared in MIT Tech Talk on April 26, 2006 (download PDF).

Topics: Bioengineering and biotechnology, Civil and environmental engineering, Environment, Health sciences and technology, National relations and service, Students


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