Americans may think the biggest threat to your garden is a determined bunny with a hankering for your spinach, but there’s a much more dangerous threat lurking beneath the surface: lead. And a whole lot of it—especially if you live in or near a major city, finds a new government study.
Although Americans’ exposure to lead has plummeted in recent years—thanks largely to the removal of lead from most types of fuel—the threat persists, says Howard Mielke, PhD, a professor of environmental health at Tulane. Why should you worry? Even very small doses of lead exposure have been shown to cause kidney and arterial disease in adults, according to a recent government study prepared with help from the Johns Hopkins Bloomberg School of Public Health. There’s also evidence linking lead to hypertension, high blood pressure, and other risk factors for heart disease, the study finds.
“Lead contamination has been a big problem for a long time, and the science is way ahead of our actions or our government policies,” warns Mielke. He says lead contaminants leach into dirt and soil can stay there for decades. That means your garden could be harboring some dangerous pollutants that can make their way into the vegetables or herbs you grow. (Where else does lead lurk? See our 7 Hidden Places Where Lead Lurks.)
Follow these steps to clean up your soil when it’s time to plant your fall garden:
Get it tested. Organic Gardening recommends having your soil tested every three to five years to not only find out about contaminants, but to also check on the nutrient components of your soil. You can send a sample of your soil to your local cooperative extension or to a private laboratory.
Import your soil. While lead contamination is a problem in most cities, Mielke says almost every urban area sits just a few miles from unpolluted stretches of countryside. “If you’ve got a car, a few buckets, and a little time, you have access to all the clean soil you need,” he says.
Move your garden. Building walls—especially painted surfaces—catch and latch onto airborne lead pollutants, Mielke says. When it rains, water carries those pollutants down into the soil at the bottom of the wall. To avoid the “lead reservoirs” at the base of buildings, choose a gardening spot that’s at least five feet away from buildings, Mielke advises.
Lay down a protective barrier. Mielke says you can purchase rolls of geotextile cloth at hardware stores like Home Depot. The next time you’re ready to plant a garden, spread the cloth on top of the soil, and the material will protect your upper layers of fresh soil from the contaminants below. “We get the unwoven type, because the threads are closer together and prevent any upward movement of contaminants,” Mielke says. (New to gardening? See why readers decided to dig the dirt with The Health Benefits of Gardening.)
Nail it. Add a handful of rusty nails to your soil, advises Jeffrey Howard, PhD, a sedimentologist at Wayne State University. Howard found that when iron breaks down, the resulting iron oxide actually attracts and latches onto lead particles, keeping them out of your groundwater and plants. The nails need not be pre-rusted when you add them to your soil; just make sure they’re made of uncoated iron. Old skillets or fireplace tools are also good iron sources.
Internet site reference: http://www.prevention.com/health/healthy-living/lead-found-city-gardens