Take the lead out of gardening

Did you hear that lead was detected in soil from the White House vegetable garden? I wasn't surprised. Although lead is not widely in use today, prior to 1978, it was a common additive in paint and gasoline. Lead was widely deposited in urban soils through car exhaust and flaking paint from building exteriors. In rural and formerly rural areas, lead may be present in soil from the historic use of lead-containing pesticides like lead arsenate. (If your neighborhood has streets with names like "orchard" or "farm", you probably live on former farmland.)

Since lead is a metal, it is persistent in soil. Unlike a volatile compound (think gasoline fumes), lead tends to stay put. Some of this lead may be bioavailable, meaning it can enter your plants and, ultimately, you and your family.

But don’t let your concerns about lead exposure dampen your enthusiasm for gardening with your kids! There are easy steps that you can take to limit this problem:

• Locate your garden away from roads and buildings. This 1995 study showed that soils in some inner-city front yards in Washington, DC were contaminated with lead; the source was traced to paint.

• Consider importing fresh topsoil for your garden. You can work this soil into your planting beds or use containers and elevated planters.

• Make sure that you and your children wash your hands after gardening and remove your shoes before coming into the house. Wipe the feet of pets that have been in the garden with you.

• Wash all fruits and vegetables thoroughly before eating them. Ingesting contaminated soil poses a greater human health risk than eating foods grown in contaminated soil.

• Studies have shown that leafy greens (like lettuce) and roots (such as carrots and onions) are the most likely to uptake metals. If you are concerned about the soil in your garden, you may want to grow fruits, like tomatoes, which are less likely to become contaminated.

At 93 parts per million, the lead levels found in the White House garden are actually quite low for urban soils; values over 400 ppm lead might raise an eyebrow. To learn more about the possible risks of lead exposure from gardening, check out:

"Leaden Gardens" from ScienceNews

"Lead in the Home Garden and Urban Soil Environment" from the University of Minnesota Extension Office

And to learn more about lead and lead poisoning, visit:

"Blood-Lead Level Basics: What You Really Need to Know" from Washington Parent

Public Health Statement for Lead from the Agency for Toxic Substances and Disease Registry.


A portion of this article appeared previously in Natural Family Online.

Photo credit: Leon Brooks, BurningWell.org

Thoughts about environmental reporting

Have you ever noticed that when you listen to the news on a topic that you know nothing about, you assume that the reporter knows what he or she is talking about? But when you are knowledgeable about the subject, you're surprised by how many things the reporter doesn't understand or actually gets wrong? It's kind of like how, when I'm driving, I expect all of the pedestrians to get out of my way. But if I'm walking, I assume that the cars should avoid me.

Anyway, I was listening to a news report yesterday about a landfill (dump) that was contaminating nearby groundwater (water contained in rocks below the ground surface) and my ears perked up. In my former life (before kids), I used to investigate abandoned hazardous waste sites (fascinating, icky places like mine tailings, old manufacturing plants, and dumps). But the reporter never talked about hazardous wastes or even hazardous substances. She said that monitoring wells around the landfill had detected "toxic chemicals" in the groundwater.

Now, this may not be wrong, but it doesn't tell us much. The word "toxic" has a specific meaning under the law, but reporters tend to throw it around randomly. As far as "chemicals" go, most anything can be a chemical. A quick search of online definitions tells us that chemicals result from reactions that effect changes to atoms or molecules.

So, have we learned anything about what's actually been found in the groundwater? No. Even assuming that the reporter is correct and the substance meets the legal definition of a toxic chemical, we could be looking the effects of anything from arsenic (a metal) to chlorine (a gas). We don't know if the substance dissolves in water or if it floats or sinks.

The reporter went on to say that the mystery substance was detected at levels that exceeded 50 times what the environmental agencies say is safe for drinking water. That sounds really scary, doesn't it? But she never said if anyone was actually drinking the water. Monitoring wells often are very shallow and examine water that most people would never drink anyway. Don't get me wrong, it's not great if water is contaminated. But it isn't quite as bad as it sounds.

So, the next time you listen to your news and think, that doesn't sound right, trust your gut. As we've discussed before, everyone has their own bias. Even me!