Arsenic and Old Lead
Some years ago, while a work crew was digging up the ugly cement slab that covered my backyard, I checked on a workman behind my shed.
He was swinging a pickax.
“How’s it going?” I inquired.
“These goddamn bricks!” he replied, slamming down the implement with another loud “choink.” He had discovered a huge cache of bricks in the soil beneath the slab.
When the fence man came, he encountered similar problems as he dug postholes. Then the landscaper came to lay new topsoil and plant bushes and trees. He found the ground infested with bricks. Why?
A couple of years later, doing some research on the neighborhood, I solved the mystery. I discovered that 200 years earlier my property had been part of a plantation that had its own brick-making operation, just about where my backyard was.
Mystery solved, but ever since then I’ve been curious about what may lie beneath our neighborhoods. Even the various American Indian tribes, nomadic as they were,
left behind some buried traces when they set up encampments here.
Unfortunately, since the days of American Indians and plantations, our yards may have acquired traces of things less innocuous than old arrowheads and bricks.
Particularly since the 2005 disaster, when floodwaters stirred up all sorts of nasty stuff and resettled it, what the soil contains has become more than just a matter of curiosity –– it’s a matter of health.
The two toxins that cause the greatest concern are lead and arsenic, says Miriam Rotkin-Ellman, a research associate with the Natural Resources Defense Council. The San Francisco-based group’s public health researchers surveyed air, water and soil quality in New Orleans following Katrina.
Not surprisingly, Rotkin-Ellman says, elevated levels of lead turned up in the soil in the historic sections of town, where houses were once coated in lead paint. Moreover, the levels were no greater than they had been pre-Katrina.
What did surprise researchers was the finding of arsenic contamination throughout the city. Rotkin-Ellman speculates that perhaps it seeped out from treated lumber used to build decks and fences. “We did not see a localized pattern the way we do see for lead,” she says.
Arsenic, she says, causes cancer and is linked to birth defects, neurological disorders, skin abnormalities and cardiovascular disease. Lead exposure can cause neurological damage in children, leading to learning disabilities and other problems.
“Children are the most vulnerable because they spend more time getting dirty and get soil in their mouths and because their brains are still developing,” Rotkin-Ellman says.
Dillard University chemistry professor Lovell Agwaramgbo has also been conducting research on lead contamination in the area. He says the distribution of the toxin is uneven. “It varies from neighborhood to neighborhood, and there are variations within neighborhoods,” he says. Sometimes the level of contamination can vary significantly on a single site.
What Agwaramgbo has found more to be more uniform is the depth of contamination. Typically, he says, lead contamination shows up primarily in the top 3 inches of soil.
Getting rid of toxins requires something more than a Saturday afternoon’s work. The Natural Resources Defense Council recommends removing the top 6 inches of topsoil from a contaminated site. For a typical single-family home, Rotkin-Ellman says, that can cost between $3,500 and $5,000. She concedes the cost is high but says it’s worth the long-term health payoff.
Agwaramgbo agrees. “Soil removal and replacement is cost-prohibitive,” he says. “But if there’s serious contamination, you have no choice but to remove the first 6 inches of soil.”
He advises testing to guide decision-making. Mild contamination may be remediated with more moderate intervention, he says.
Agwaramgbo recommends partitioning your yard into 10-foot-by-20-foot sections and taking samples from each section. The Louisiana State University’s AgCenter provides low-cost testing, he says.
In the meantime, precautions are necessary. If you have a vegetable garden, Agwaramgbo says, make sure it’s raised and you’re not planting directly in the ground. Sunflowers and other plants, such as certain cabbages, can help to gradually remove the toxins. They must ultimately be removed, however, because the toxins migrate into their stems and leaves. (See “Keep on the Sunny Side,” p. 20, for more information on sunflowers and soil testing.)
Rotkin-Ellman recommends holding off on gardening until your soil is tested. Otherwise, she says, wear gloves and try to keep the soil moist while you’re working. You don’t want the wind blowing toxic dust into your lungs.
As for the kids, Rotkin-Ellman recommends what your mother would have ordered: Take your shoes off before entering the house, and wash your hands after playing outside.
This being New Orleans, the land of raised houses, it’s also probably a good idea to restrict access underneath. In my day, kids used to love to play “army” beneath houses in the neighborhood. War is hell, I guess, but Lord knows what we were breathing down there.