Months after Hurricane Katrina's floodwaters receded, New Orleans' Lower Ninth Ward was still covered with a layer of crusty dark dirt.
"That is sediment that came from the contaminated industrial canal," said Pam Dashiell, a neighborhood activist and long-time resident of the Lower Ninth Ward. "The sediments in the industrial canal were absolutely contaminated. Our neighborhood association had a study done (before Katrina) that found all kinds of toxic sediments, heavy metals -- arsenic lead -- far above the standards of the Louisiana Department of Environmental Quality. And post Katrina all of those chemicals were found in the soil."
Dashiell said her weekly visits from her granddaughter were the highlight of her week before Katrina, but she would not want her or any other children to spend time in the Lower Ninth Ward until the contaminated soil is removed.
"You know, we want our children back," Dashiell said. "And children playing in an area that has toxic sediment, where the wind blows, etc., is not a scenario that any of us would like to see. We want a safe sanitary community. Something has got to be done."
Some scientists and environmental activists echoed Dashiell's concerns. They said that the dried muck from the floodwaters that still covers some neighborhoods could pose health risks to people who return to some inner city neighborhoods. Children are particularly vulnerable to toxic chemicals from the soil because they play outside and put their hands in their mouths.
Experts disagree about whether the floodwaters are the source of the high levels of contaminants or if the contaminates were in the soil before the storm. But the fact that there are high levels of lead, arsenic and other hazardous chemicals in some neighborhoods is not in dispute.
Tom Harris, a toxicologist at the Louisiana State Department of Environmental Quality, said data from 800 soil samples taken by the state and federal government since the hurricane show that in most places it is safe for people to return. "We are seeing overwhelmingly sediment and soil concentrations that are below residential standards for long-term exposure," Harris said. "It's not as bad as what was first reported or we feared at first."
He conceded that in the Lower Ninth Ward and some of the city's other older neighborhoods, lead and arsenic were found at levels that exceed public health standards. However, he says Katrina can't be blamed for that.
"What we're seeing in samples in some of these older neighborhoods is pretty consistent with what was found before Katrina and what's found in urban neighborhoods throughout the United States," Harris added.
Harris said he has seen no indication from the data that the floodwaters from the industrial canal were more toxic than those from Lake Pontchartrain, which was the source of flooding for most of the city.
It may be that Dashiell and Harris are both at least partly right. New Orleans' problem of soil contamination pre-dates the hurricane, but Katrina may have spread it around or exacerbated it.
Howard Mielke, a professor at New Orleans Xavier University College of Pharmacy, has sampled the soil throughout New Orleans and created a map that shows the areas with high levels of lead. They include the old neighborhoods in near downtown, such as central city and the Upper Ninth Ward.
"They have all of the combination of things that could cause a problem," said Mielke, such as high traffic flows on nearby streets when lead gasoline was still in use. "That would have generated a lot of lead coming into the city," he said. Old houses also pose a risk because they're covered in lead-based paint. People often sand them before repainting them, adding enormous amounts of lead to nearby soil.
Mielke says lead in the soil is a big reason that before Katrina a quarter of the children in the inner city of New Orleans had blood-lead levels high enough to cause learning disabilities and behavioral problems. Before the storm, Mielke was working with local families whose children suffer from lead poisoning. Several months after Katrina, he went back to check on them.
Bettina Reutter's son, Ky, had tested positive for serious lead poisoning a year and a half ago, when he was 2.
The Environmental Protection Agency (EPA) says anything above 400 parts-per-million lead in soil is unsafe for children. Other countries set that level at 100 parts-per-million. But Mielke says it was much higher than that in Ky's back yard.
In Ky's play area, the samples showed the medium was well above 1,000 parts-per-million lead and the maximum was 20,000 parts-per-million lead, Mielke said. "It was very contaminated."
Mielke organized volunteers to spread truckloads of clean soil around Ky's yard.
"I knew immediately that at least we could make a difference for Ky's life by changing the soil, because the child was playing in a hazardous waste material, basically," he said.
After several months, Ky's blood lead level returned to normal. Reutter says she saw the difference in her toddler's behavior.
"Yeah, I thought he calmed down a little," Reutter said. "He did get somewhat able to sit down and concentrate."
Then Hurricane Katrina chased Reutter's family out of their home. After they returned to New Orleans, Reutter's daughter, two-year-old Analia, tested high for lead.
Mielke retested the soil in the backyard and found that the clean soil was covered with a very thin layer of more contaminated soil. His theory is that floodwaters brought in that contaminated soil or winds blew it in during the long-drought that followed the storm. Reutter says where ever the contamination was, Analia found it.
"She's sucking on her fingers so anything she touches she puts in her mouth. It might not even be here. There's a park where I go to, it might be lead from there. It might just be lead from the street," Reutter said.
Until the whole city is cleaned up, Reutter says children like hers will be vulnerable to lead poisoning.
Mielke said it is possible that state officials are right, and lead levels are not much worse than before Katrina. But even before Katrina, the soil contamination problem was so dangerous for children that it required urgent action.
"The city of New Orleans has a serious lead problem, and it needs to be dealt with. And to turn that around as well, it's not a problem because this is what it was before, well, what it was before was a very serious problem," Mielke said.
Experts from the environmental group Natural Resources Defense Council analyzed the government's sediment sampling data, and they make the case that it shows that flooding increased the risks from lead, arsenic and other contaminates.
Steve Presley, an environmental toxicologist from Texas Tech University, has done his own sampling since Katrina. He's found levels of lead and arsenic in some parts of New Orleans that are several times higher than what the federal government says is safe. He says it shouldn't matter whether the toxins were present in the soil before Katrina.
"If we as a nation are going to rebuild a city that was a vital part of our natural culture," said Presley, "let's make sure it's safe for people to return to that area. Let's do it right," he said.
The answer, Mielke says, is to spread clean soil over yards, parks and vacant lots across the city. He hopes the massive rebuilding effort underway will provide an opportunity to clean up the soil and make New Orleans a safer place for children than it was before the storm.
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