Toxic Threat Still Vague but Ominous, EPA Says

Calling Hurricane Katrina the largest disaster that the Environmental Protection Agency has ever encountered, the nation’s top environmental official said Wednesday that the Gulf Coast was still facing an array of serious health threats, including lack of clean drinking water, astronomically high bacteria counts and unsafe levels of several toxic metals in floodwaters.

EPA Administrator Stephen L. Johnson said it was impossible to estimate how long the cleanup would take because no one knows the magnitude of the problems.

Signs are emerging that there could be widespread hazardous waste in New Orleans that could delay rebuilding efforts, although the EPA so far says it has detected just three chemicals in the floodwaters at unsafe levels.

Hexavalent chromium and arsenic, which are known human carcinogens, were reported Wednesday in floodwaters in some New Orleans neighborhoods at levels that are unsafe for drinking water. The latest available samples were taken Sept. 4 through Sept. 6. The chromium compound is used in metal plating. Arsenic, found naturally in the Earth’s crust, occurs in pesticides and wood preservatives.

Since Sept. 3, the agency has reported unsafe lead levels in floodwaters, including one sample that exceeded the drinking-water standard 15-fold. Lead can damage the brain of a fetus or child if it is ingested.

The health standards for arsenic and chromium are based on long-term dangers -- the risk of cancer associated with a child drinking a liter of tainted water a day -- so there is little immediate danger because people are not drinking the floodwaters. But the findings suggest that significant amounts of at least a few contaminants have polluted the area and probably pose a long-term threat to public health and the environment.

Nearly 1,000 drinking-water systems remain disabled or impaired because of power outages or structural damage. Many people have been told to boil their water.

Some environmental researchers are suspicious of the reliability of the EPA’s tests because they have reported no detectable amounts of benzene or several other substances in petroleum products, even though oily sheens are visible on the floodwaters.

But Johnson said petroleum residue has been absorbed into the dirt. He said the soil and other sediment contain so much petroleum-based material that it is hard to isolate specific compounds in the tests. Johnson said the EPA has requested assistance from a panel of scientific experts on how to analyze the samples.

The visible oily waste in the sediments could mean massive amounts of soil may have to be excavated or treated, and perhaps taken to special landfills. Chemicals left in the soil can leach into groundwater and contaminate the air and drinking-water supplies, as well as crops and gardens.

New Orleans Mayor C. Ray Nagin has said the EPA test results will be a key factor in determining how quickly residents can return.

Johnson would not speculate on whether the contamination will delay rebuilding parts of the city.

“Our top priority is to assess what the impacts are and conduct a cleanup operation -- just as quickly as possible -- that is done right” and protective of public health, he said.

The floodwaters in New Orleans’ residential neighborhoods are being continuously tested for more than 100 compounds, including pesticides and industrial chemicals. But most have not been detected, and other than the chromium, arsenic and lead, none has been detected in concentrations that exceed drinking-water standards, according to data that the EPA released from sampling at 29 sites.

However, other chemicals are showing up in the water at low levels, including some pesticides; mercury; copper; barium, a metallic element used in the oil industry; thallium, another metallic element; and toluene, which is found in paint, gasoline and other petroleum products.

Some experts have questioned whether the tests can adequately assess the hazards.

John Froines, director of UCLA’s Center for Occupational and Environmental Health, said just comparing the chemicals to drinking-water standards may not be enough to protect public health. Some, such as toxic ingredients in petroleum products and pesticides, can be absorbed through the skin and others can cause allergic reactions.

“There must be over 100,000 volunteers and National Guardsmen and other officials there,” Froines said. “These people are likely to be wading in water, and they may have some of the most significant exposures.

“We know you can get massive uptake [of some chemicals] through the skin in certain occupational settings. I don’t have a sense that anybody is thinking about that,” Froines said.

Because the highest concentrations found so far are metals, the region “may have been spared” exposures similar to the World Trade Center disaster, where smoke and dust were toxic, he said.

“The question is what is going to happen to those metals?” Froines said. “There are long-term issues with respect to hazardous waste and plants taking up sediments, and people with gardens.”

Federal and state officials, he said, should assemble a group of scientists and regulatory officials to determine which people may have been highly exposed and then consider testing their bodies for chemicals.

Although the nation has suffered other large floods, “this is not comparable at all, because of the scope and how high the water was and for how long, and the size of the population. We didn’t have people wading in 25 feet of water for five days” after floods in the Midwest, said Roger Lewis, director of the St. Louis University School of Public Health’s Environmental Health Research Lab.

Johnson acknowledged Wednesday that the EPA’s floodwater tests offer “just a snapshot.”

He said there is no doubt that the floodwater is unsafe, largely due to high bacteria counts. Bacteria counts remain much higher than acceptable levels for human contact, which indicates that raw sewage is still in the streets, according to samples collected Saturday.

The EPA has advised emergency crews and the public to avoid contact with standing water when possible and to wash exposed skin with soap and clean water.

He said the EPA has enough money for its emergency work, with more than 600 employees at the scene, mostly in Louisiana.

Environmental officials are also concerned that chemicals might be flowing off five Superfund sites -- among the nation’s most hazardous dumpsites -- near New Orleans. One Superfund site, the Agriculture Street landfill, remains underwater. A cleanup occurred there in 2000, but some residue remains and the EPA has not tried to assess whether contaminants have flowed off the site.

Five major oil spills have been discovered in the New Orleans area since the hurricane, according to the EPA.

Maj. George Stejic, a member of the Army Corps of Engineers team that is in charge of pumping water from the area, said Wednesday that one spill involved a large tank that shifted, releasing 250,000 gallons of a petroleum product into floodwaters. He said the corps was working with the EPA to contain the spill and was using booms to keep the product from reaching pumps.

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Times staff writer Ralph Vartabedian in New Orleans contributed to this report.