New Orleans floodwater is not “toxic soup”
Experts and residents express frustration with EPA’s bumbling response.
Shortly after Hurricane Katrina slammed into the Louisiana coast, flooding the city of New Orleans, journalists began reporting on a “toxic soup” of chemicals and dangerous microbes bathing the city. Based on no reported data, these stories nevertheless seemed reasonable; the city’s sewer system had flooded, and thousands of cars, houses, and chemical storage tanks lay beneath water, which in part of the city reached more than 3 meters in depth. In addition, 24 Superfund sites are in the affected area, and the U.S. EPA and the U.S. Coast Guard have tallied more than 400 oil and hazardous chemical spills.
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However, research posted to ES&T’s Research ASAP website (es0518631) finds that the water that drowned New Orleans was no more toxic than typical floodwater washing down an urban street after a hard rain. Researchers expressed surprise at the findings but warned that it is still unknown whether the muck left behind is toxic.
“We don’t see the very elevated levels of toxics that would make you think of this water as toxic waste,” says the study’s lead author, John Pardue, director of the Louisiana Water Resources Research Institute at Louisiana State University (LSU). “What was so unique about this event was that we had such a large volume of water and so many people wading around in it for extended periods,” he says.
Danny Reible, chair of environmental health engineering at the University of Texas at Austin, says the study presents the first comprehensive data that he has seen on the floodwaters. “The bottom line is that it’s not a chemical environmental disaster, although you can’t rule out areas that might be impacted from local chemical spills,” he says.
Five days after the hurricane hit land on August 29, Pardue’s team boated into New Orleans with police protection and collected water samples from street intersections in the Lakeview neighborhood, near the levee break, and in Mid-City, close to the Superdome. Four days later, on September 7, he collected more water in Tulane–Gravier, a neighborhood just blocks from the Superdome, where thousands of residents sought refuge from Katrina.
Samples collected from various depths of the water column were later measured for several parameters, including turbidity, pH, and concentrations of organics, nitrogen, dissolved oxygen, and metals. Surface waters were depleted of oxygen, whereas lead, arsenic, and, in some cases, chromium exceeded drinking-water standards. Pardue reports that the values were normal for storm water, as were the levels of fecal coliform.
The LSU researchers also failed to detect extremely high levels of benzene and other carcinogens found in gasoline, although coauthor Louis Thibodeaux, a professor of chemical engineering at LSU, says that he expected to see higher levels. However, he calculates in the paper that most of these chemicals quickly evaporate.
“All of us around the world watched those people on television wading through oily water, but the benzene and many volatiles were gone,” says Thibodeaux. He adds that oil spreads out across water in a layer only millimeters thick, which tricks people into believing that a huge quantity of petroleum has contaminated the water. “It only takes a few drops to make sheen on the water surface,” he adds.
However, Thibodeaux says that many of the chemicals that did not evaporate may be bound to particles deposited in the mud and grime left behind.
Pardue raises similar concerns. “People are absolutely crazy to be going back into their homes,” he says. Because mold is an increasing problem in the houses left standing and sediments are still essentially unexamined, Pardue says that he is not certain the city is safe to inhabit.
Where are you, EPA?
The LSU findings are particularly important because experts are charging that EPA is failing to provide adequate, timely information that can be understood by the public. After people had been trudging through the water for more than a week, EPA began posting data from water samples on a website. This action raised an obvious question about how people stranded in New Orleans, many of whom are poor and without electricity, were supposed to access the information.
And data that EPA made available were often confusing, even to those with technical expertise in water chemistry. “They should certainly be capable of providing some context for this information,” says Pardue.
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“All EPA did was put the information on the web without any information of what it meant.” says Mark Schleifstein, an environment reporter with the New Orleans Times–Picayune. “Information afterwards was in the context of certain standards, but it was uncertain why those standards were chosen.” Schleifstein later filed requests under the Freedom of Information Act to force EPA to provide details of chemical leaks into the water.
Pardue says that he had initially planned to release his data to Schleifstein and other reporters but decided to go through a peer-review process after seeing that EPA was performing so poorly and providing no context other than drinking-water standards. “That really doesn’t have any kind of relevance,” he says.
When contacted by ES&T about Pardue’s research, EPA would only respond with an emailed statement from an unnamed EPA scientist: “The findings in the article are consistent with what we have been finding in our sampling and what we have been saying about the conditions in New Orleans.”
On September 29, a month after the hurricane hit land, Marcus Peacock, EPA’s deputy administrator, told the U.S. Congress, “I don’t think you can say from what’s been assessed so far that there will be long-term effects.” Peacock added that contaminants may cause localized effects in areas close to spills.
However, Peacock offered little help when asked whether EPA was taking charge to ensure that citizens are safe. “That is up to local health officials and the city’s office to determine whether or not a particular room or neighborhood is safe for someone to go back into,” he said.
Mayor William Rutledge of Pontotoc, Miss., along with others, saw the problem differently. Referring to EPA, Rutledge testified, “The problem has been communication—getting out the word and stepping up to the plate and deciding that it’s safe. We don’t think [EPA] has been fulfilling that obligation.”
Further research
All the water that entered New Orleans was later pumped into nearby Lake Pontchartrain, a shallow, brackish lake with a surface area of more than 640 square miles. The lake is regularly used for recreation and commercial crabbing and is a catch basin for New Orleans’ storm water runoff. Pardue says that although the concentrations of metals in the water pumped into the lake were normal for floodwater, the lake has absorbed the equivalent of many years of runoff in only a few weeks.
Concentrations of zinc and copper, Pardue says, may pose a problem for fish that have less tolerance for these metals than humans. “So the metals going back into the lake are at much more toxic levels than we report for humans,” he says.
Because more than 100,000 houses were flooded, Pardue says that he is now beginning to look for other chemicals that might not normally be detected in mud left behind after a flood. He is also working with horticulturists to see whether this muck, which contains salt and other chemicals, may kill off the city’s plants and trees.
“If this was a waste site, EPA would require a cleanup to a certain level before they let anyone go back in,” says Wilma Subra, president of Subra Co., Inc. To address the concerns of local residents, Subra is conducting her own tests of the sediments. She advises residents to not enter the city unless they wear a respirator, boots, and gloves. She notes that Wal-Marts within 100 miles have sold out of such equipment.
As for the city and state officials, she says, “All they know is that their people want to go home. They’re looking for EPA to establish criteria that are safe for people, and EPA is not doing that.”
