Tuesday, January 6, 2009

Getting the Lead Out

My youngest son gave me a campaign-style pin for Christmas that says “Turn your lawn into a garden.” The pin has prompted some interesting conversations while I’ve been out. It turns out that plenty of people plan to do exactly what the pin says. However, a couple of these people live in older homes and should probably consider learning more about possible lead contamination in their soil before planning their food gardens.

Older homes that have been painted, scraped, repainted, scraped, repainted, etc, for years and years may have had old lead-based paint chips dropped into the soil around their foundations. While it is possible that any contamination would be at a low level, it is also possible that the level is high.

For example, one year one of my sisters was looking for a house to buy in Tulsa, OK, and she found a really cute older home that she was interested in, but her children were young and she was concerned about the possibility of lead contamination around the house. I think the pipes were her main concern, but it turned out that the soil around the house’s foundation was contaminated with lead.

This sounds bad, but the recommendation that came back with the test results was that the soil within only 2 feet of the house—since lead does not migrate through the soil to more distant locations—be dug up and removed, with fresh soil brought in to replace it. Without this precaution, the risk of her children’s being affected by lead poisoning was unacceptably high, because, one way or another, children eat dirt.

However, even without removing this soil, my sister could have grown veggies in that yard, following guidelines in this article from the University of Rhode Island Landscape Horticulture Program which explains ways to limit the risk of ingesting lead through home-grown produce when soils are known to be contaminated. Although one obvious method is to wash fruits and vegetables really well, the article explains,

“Gardeners can use several methods to reduce the risk of lead poisoning from lead contaminated soils. Fruit and vegetable gardens should be located away from old painted buildings, heavy traffic and sites where sludge with heavy metals was applied. Vegetables and fruits can accumulate lead in their leafy green tissues, although lead accumulation will be lower in fruits. In high-risk lead areas, grow crops such as tomatoes, eggplants, peppers, squash, melons and cucumbers rather than leafy greens such as lettuce, chard, collards or spinach. Crops such as carrots, radishes, turnips, onions and potatoes can accumulate lead and should not be planted in heavily contaminated soils.”

The article emphasizes the importance of keeping contaminated soils out of the home, on foods but also on the gardener’s person, by washing up and using mulches to reduce dust exposure. I expect that keeping yard-shoes outside (to avoid tracking in contaminated soil) would also help.

Anyone concerned about possible contamination of their soil should read the whole article and then consider having their soil tested before growing food in the yard. However, this article and others I’ve read on the same topic are reassuring about the ability of most yards, with proper precautions, to produce good, safe food.

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