(The Associated Press circulated the following article on September 20.)
NEW ORLEANS, La — As the floodwater recedes in New Orleans, scientists are testing it and the mud it leaves behind to answer a big question: Is the Big Easy on its way to becoming the Big Risky?
The answers aren’t all in yet, but many experts are optimistic that most of New Orleans could be safely resettled in a few months.
The search for hazardous chemical contamination in the water and flood sediment are part of the larger question of what the long-term environmental impact of Hurricane Katrina will be across the broad region it struck. The hard data scientists need to gauge the long-term risks are still emerging.
So far, though, results of the testing in New Orleans are encouraging, says Jerry Fenner, who’s leading a Centers for Disease Control and Prevention team that is assessing the city’s environmental health risks.
”All the data to date show there should not be any long-term health risks to the population,” Fenner said late last week. While considerable concern has focused on germs lurking in New Orleans’ sewage-contaminated floodwaters, they won’t survive long once the water is pumped away.
But the chemical testing is far from over, and that leaves room for plenty of opinions about how bad contamination will prove to be for the city:
–”It could indeed redraw the map of New Orleans,” with large areas going off-limits to homes or schools, said Dr. Tee Guidotti of George Washington University’s school of public health and health sciences.
–”I certainly don’t think this is going to render New Orleans uninhabitable,” said Richard T. Di Giulio, a professor of environmental toxicology at Duke University.
–”I expect there is a good chance that much of New Orleans will be able to return largely unscathed from long-term chemical contamination,” said Danny David Reible, a University of Texas at Austin professor of environmental engineering who has studied chemical contamination from hurricanes.
Di Giulio and Reible stressed, however, that there may be local areas with contamination problems if floodwaters flushed hazardous material out of particular sites. For example, a spill from a large oil tank at a refinery in St. Bernard Parish, a suburb downriver from New Orleans, ”could pose more serious and longer-term problems,” Reible said.
Oil from the spill has stained lawns, shrubs and tree trunks black, as if they’d been burned. A canal near the field of storage tanks where the spill occurred is black.
As for New Orleans itself, floodwater test results released so far show that in some places, levels of lead, hexavalent chromium — a potential cancer-promoter — and arsenic exceed the accepted limits for drinking water. Of course, nobody is suggesting that anybody would drink the stinky, germ-laden floodwater.
In fact, for long-term health implications in New Orleans, the real question is what will remain in the sediment that’s left behind when all the water is pumped away. Preliminary testing of sediment samples has found some places with elevated levels of compounds like diesel and fuel oil, some of which might stick around in the environment for years.
But the detected amounts of hazardous metals like lead were too low to suggest a health risk, the Environmental Protection Agency announced Friday.
The agency stressed that the initial results, from 18 samples, represent just the beginning of the sampling program and may not be typical of all sediment in the area.
”I would not foresee a long-term risk based on this report,” said Jerald Schnoor, professor in the environmental engineering department at the University of Iowa.
Di Giulio said the question of where to put all the sediment could become an environmental concern. Some will probably require treatment or disposal in hazardous waste sites, he said, so officials will have to carefully look for locations with contamination.
Even before testing began, scientists knew that there were plenty of potential sources of chemical contamination: Oil and grease from flooded parking lots and roads; other petrochemicals from refineries and underground gasoline tanks; chemical leaks from industrial sites; household hazardous waste like pesticides and herbicides, washed away from more than 160,000 flooded homes; an estimated two tons of mercury just from switches in automobiles; material in damaged railroad cars; and pollutants from Superfund sites, including a flooded New Orleans landfill.
The environmental group Greenpeace said it has found more than 350 petroleum facilities, chemical plants and hazardous waste sites in the hurricane-affected areas of Louisiana, Mississippi and Alabama.
But Mississippi apparently won’t suffer long-term risk to human health from chemical contamination after Katrina, said Charles Chisolm, executive director of the state’s Department of Environmental Quality.
Its biggest environmental problem will be disposing of huge piles of debris, he said. The debris has to be buried in special sites because it could leak substances like asbestos, lead, or other chemicals from demolished buildings, Chisolm noted.
The volume of debris far outstrips the state’s supply of specialized disposal sites, Chisolm said, and a search is under way for additional locations.
Out in the Gulf of Mexico, a federal research ship has been taking water samples near the coastal damaged coast. It will also inspect Mississippi River sediments and test fish and shrimp for signs of toxic contamination or germs that might make them risky to eat.
Experts say the long-term impact on wildlife is hard to predict because the effects of Katrina are so different from what they’ve encountered before.
The floodwater being pumped out of New Orleans is ”a toxic gumbo like we’ve never seen,” said John Rodgers of Clemson University. It’s being pumped into Lake Pontchartrain, but Rodgers said he believes some of it will enter the Mississippi River as well.
Scientists will have to monitor river sediments for toxic metals and pesticides, which in the short term could kill fish and crustaceans or make them hazardous to eat, he said. Over a longer period, Rodgers said such contamination could diminish fish reproduction for several years.
Elsewhere, Katrina has disrupted near-shore fish habitat, spewing debris into spawning areas. Rodgers said he expects a relatively quick recovery.
But Alan Covich, director of the University of Georgia’s Institute of Ecology and a researcher of environmental impacts of hurricanes, said Katrina brought so much devastation to the coast and inland that ”we don’t know enough about how things will recover.”
”In my experience, this is unique,” said Covich, president-elect of the Ecological Society of America.
”Nobody knows how long it’s going to take for the oysters to come back” and whether they’ll be free enough of toxins to eat for months to years, he said.
It’s a dramatic example of a destructive, wipe-the-slate-clean environmental disturbance like tidal waves, drought and fire that can strike anywhere, he said.
”I think it’s clear to everybody that this isn’t the last of these we’re going to see.”