BATON ROUGE, La.—State environmental health officials are cautiously optimistic that New Orleans has avoided its two biggest environmental threats: sludge that's so contaminated the city is uninhabitable, and Lake Pontchartrain turned into a toxic soup.
But as the first steps of repopulating the city resumed Monday, tests showing whether there could be long-term health risks haven't been completed yet.
Preliminary testing shows that Pontchartrain—the huge brackish lake along the city's northern edge—and flood sediment in the city contain dangerous levels of bacteria. But these should diminish quickly as the city dries out and pumping into the lake stops.
Officials stress, however, that the testing so far has concentrated on dangers that would make people sick immediately. They haven't done the testing that would show the health risks of long-term exposure.
"The numbers don't show any smoking guns, but I am concerned about people setting up shop in there before that question is answered," said John Pardue, the director of the Louisiana Water Resources Research Institute, an independent public safety group.
Pardue said that although the water and sludge contained toxic chemicals, they weren't at levels that would make people sick with short exposure.
However, Hurricane Rita reflooded areas of the city and added a new layer of sludge, said Ivor van Heerden, the director of the Center for the Study of Public Health Impacts of Hurricanes at Louisiana State University.
The most immediate threat is bacteria. E. coli and other harmful bacteria exceed health standards by a factor of 10.
Katrina flooded 25 major and 32 minor sewage-treatment facilities, releasing hundreds of millions of gallons of sewage into the city. Decaying animal and human remains also are contributing bacteria.
As a result, health and rescue workers being sent into the city must be vaccinated for tetanus and other serious infectious diseases, said Darin Mann, a spokesman for the state Department of Environmental Quality. They wear rubber gloves and boots that have puncture-proof soles to prevent nails and other objects from penetrating.
Health officials recommend that everyone in the city wear a respirator mask. As the city dries out, dust will be a problem. Breathing dust under any circumstances is unhealthy, but the dust in New Orleans may contain contaminants, they said.
Oil products are the most prevalent contaminant in the water and sludge, coming from refineries along with submerged cars and gas stations.
Testing also has found slightly elevated levels of lead, arsenic and other metals, as well as pesticides and herbicides. These come from flood runoff as well as household and industrial sources.
Sampling now is shifting to assessing the long-term health threats in the city—problems that may arise as a result of repeated exposure to low levels of contaminants, said Dana Shepherd, the Katrina data-assessment team leader with the state Department of Environmental Health.
Cleanup efforts will have to reach the lowest layers of sediment and debris before long-term health threats can be determined, a process that will take weeks.
As untreated floodwater is pumped into Lake Pontchartrain, the lake has taken on a distinct septic smell, Mann said. Like the floodwater and sludge in New Orleans, the lake has lots of bacteria but doesn't have high levels of toxic chemicals.
"It's a bacterial, or septic, soup, but it's not a toxic soup," Mann said.
At 630 square miles, Pontchartrain is the nation's second-largest saltwater lake, behind the Great Salt Lake. Experts estimate that floodwater from New Orleans will displace no more than 10 percent of the lake's volume, meaning pollution from pumping will be limited.
Most of the damage to the lake was caused by natural sources. Katrina washed tons of leaves, branches and other natural debris into the lake and the streams that feed it. This debris is rotting, sucking oxygen out of the water and killing fish.
"I expect a total fish kill in streams up to 15 miles above the lake due to low dissolved oxygen," said Mark Lawson, inland fisheries biologist for 13 parishes in eastern Louisiana. Limited fish kills in the lake also have been reported.
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(Sneed reports for The (San Luis Obispo) Tribune.)
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(c) 2005, Knight Ridder/Tribune Information Services.
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