September 09, 2005
Friday

As the floodwaters are gradually pumped out of New Orleans, much of the mixture of waste and chemicals suspended in them will be left behind either in sensitive wetlands or in the soil of the city itself, raising new health and environmental concerns.

Failures to levees after Hurricane Katrina's assault left about 80 percent of the city flooded with water up to 20 feet deep, water that quickly became fouled with chemicals, pesticides, oil, garbage, human waste and human and animal remains.

Bacterial activity in the water was so high that researchers from Louisiana State University found virtually no oxygen left in samples they took around the city last weekend.

State environmental officials say that more than 500 sewage-treatment plants were knocked out by the storm. The flood submerged more than 6,000 facilities with underground fuel storage tanks, some 160,000 homes and tens of thousands of vehicles.

"Just think that every household has a certain amount of Mr. Yuk stuff stashed under the kitchen sink or in the garage, and all that material is presumably mixed into the water to some extent," said Thomas Miller, a water-quality specialist at the University of Maryland who studies contamination problems after floods and other disasters.

"Either all that material is going to be pumped out with the water into Lake Pontchartrain, or it's going to settle into the muck, the silt that's left behind everywhere after a flood," Miller said.

Mike McDaniel, secretary of the Louisiana Department of Environmental Quality, told reporters that sampling of the water is ongoing, and that there appear to be large numbers of contaminants, but officials feel there is no choice but to pump the floodwater into the lake and the Mississippi River. "We have to get the water out of the city or the nightmare gets worse," he said.

Lake Pontchartrain, the second-largest saltwater lake in the United States behind the Great Salt Lake in Utah, drains through narrow straits that lead into the Gulf of Mexico.

While environmental advocates expect the southern end of the lake will sustain some damage, no one can foretell how much or for how long. "The wonderful thing about nature is its resilience," McDaniel said.

Miller agreed that "nature is pretty good about self-recovery, but a lot depends on what man does to hinder or assist in that recovery. The nice thing about wetlands is that they can cleanse and filter water as it moves through, but too much contamination can overwhelm this natural filtering system and destroy it."

Within the city, officials for days have been warning everyone to stay out of the filthy water, but thousands of residents still wade or float through the streets. Anyone who ingests any of the stuff, or has open sores or wounds that get wet, risks illness or infection, and hundreds have been treated for festering wounds and skin rashes.

Disease experts say the biggest microbial-related health threats from the water are common staph and strep infections, particularly strains that are resistant to many antibiotics.

Exotic diseases like cholera or typhus are not considered a threat, because they're not present in the population. "In the city of New Orleans, cholera has not been present for years," said Dr. Julie Gerberding, director of the federal Centers for Disease Control and Prevention.

And despite the psychological impact, public health experts said the submerged bodies of storm victims don't pose a disease threat, either. Most viruses and bacteria that cause disease can't survive more than a few hours in a dead body, and while recovery workers do need to decontaminate them before they're prepared for burial, studies show that the bacteria involved in decomposition don't cause serious diseases.

"Survivors are much more likely to be a source of disease outbreaks," said Jean-Luc Poncelet, head of emergency preparedness and disaster relief for the Pan American Health Organization.

Lingering floodwater may eventually increase the risk for mosquito-borne illnesses in the region, too, health officials said. But historically, extreme weather actually washes out populations of the pests for a few weeks, but then new generations begin to hatch, so spraying is high on the agenda for public health workers in the next month.

Less clear is how the lingering sludge from the flooding will be handled. Lt. Gen. Carl Strock, head of the Army Corps of Engineers, told reporters that "we will look for hot spots as we draw the water down, and if we get an area that is particularly toxic, we will try to control that instead of dumping it back into the lake."

Still, contaminated mud inches and perhaps several feet deep will be one of Katrina's longest-lasting legacies in the city. What's not removed promptly will move into storm drains every time it rains, or raise the risk of respiratory illness as it dries out on walls and floors of buildings.

"With the soil so saturated down in the bowl, you have to wonder how long it might take to really dry things out and clean up enough to start any rebuilding," Maryland's Miller said.

On the Net:

http://www.cdc.gov

Epa.gov

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