Toxic sediment requires extensive cleanup effort

Flood deposit testing revealed contaminants that pose long-term hazards.
DALLAS MORNING NEWS
DALLAS -- The Army Corps of Engineers is planning one of the biggest environmental cleanups ever attempted: scraping miles of sediment laced with cancer-causing chemicals from New Orleans' hurricane-flooded neighborhoods, The Dallas Morning News has learned.
Contaminants in the sediment include toxic metals, industrial compounds, petroleum byproducts and a banned insecticide, all at levels that signal potential cancer risks or other long-term hazards, a Dallas Morning News review of government test results shows.
The cleanup plans would involve crews using front-end loaders to scoop up contaminated sediment that Hurricane Katrina floods left in yards, playgrounds and other spots throughout the Greater New Orleans area. In some instances, protecting people might require steps less radical than removing soil, such as planting grass to cover contaminated yards.
Uncertainties remain
It's not clear which remedy would apply in which neighborhoods, or how officials will decide. The plans have not yet been completed or made public but were described to The Dallas Morning News by several sources familiar with them.
In all cases, however, the task would be complex and huge, with crews covering nearly an entire city and its suburbs while maneuvering around the remaining debris and damaged houses.
Concern about contamination is a major reason why the city is allowing residents from some of the most heavily flooded areas only the chance to check on their houses, not stay, said Dr. Kevin U. Stephens, New Orleans' city health director.
Proper removal of the contaminated sediment will ensure that residents won't face undue toxic risks as a result of the floods, Dr. Stephens said.
"If the corps does what it's supposed to do, it should work," he added.
Decisions are still evolving on whatever follow-up testing might occur to check the long-term health of the New Orleans environment after the sediment is gone, said William H. Farland, the Environmental Protection Agency's acting deputy administrator for science.
Local environmentalists complain that they and other members of the public have been shut out of the decisions.
"We've cooperated with the EPA on a great many things over the years," said Wilma Subra, a consulting chemist in New Iberia, La., who is monitoring the hurricanes' environmental impact for the Louisiana Environmental Action League, an advocacy group. "Now, we're having a hard time getting our calls returned."
EPA spokeswoman Eryn Witcher said the agency is releasing information as quickly as possible, but she and other EPA officials emphasized that they can offer only their best advice. Decisions, such as repopulating New Orleans, are strictly up to city officials, she said.
Crucial information
Information about the possible long-term risks in dozens of New Orleans neighborhoods is crucial as people decide whether to return home and as the city decides where or whether to rebuild.
Despite one widely publicized study that said the Katrina floodwater was no more polluted than typical urban floods, The Dallas Morning News' examination of the EPA's tests of flood-deposited sediments reveals long-term health concerns if the contamination were to remain.
Contaminated sediment was always a more serious long-term worry than floodwater, since the water was quickly removed. In September, experts advised the EPA that toxic dust could spread as the sediment dried.
The EPA and Centers for Disease Control and Prevention in Atlanta also warned that comprehensive tests were needed "to identify any widespread contamination or selected hot spots and to ensure the safety of returning inhabitants or for redevelopment."
The EPA's sampling plan, assembled in just a few days in mid-September and quickly reviewed by outside scientific experts, targeted nearly 200 toxic substances in sediment left by the receding water.