Lead Update

Our post about a high soil lead level needs an update. I asked my doctor do a blood test to check for lead levels since we’ve eaten plants grown in the backyard and done a whole lot of digging over the past 13 years. The good news is that no lead showed up in my blood.

In the interest of “testing the testers,” I took one soil sample and split it in three, sending one sample to Wallace Labs, one to the University of Massachusetts and the other to Timberleaf Soil Testing. I’ll report back on what those tests come up with.

Hopefully that first test with the high lead level was a mistake. I’ve realized that one small lead paint chip in a soil sample could easily throw off the test since we’re checking for something that is measured in parts per million. I’ll admit that this lead issue is definitely a complicated problem that is at the limits of my grasp of scientific methods. I appreciate all of you who have chimed in with advice, prayers and good wishes.

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13 Comments

  1. In this situation would it be possible to test samples from the plants themselves for lead? That would probably eliminate the paint chip possibility.

  2. Good point Sara A. Wallace labs offers plant tissue testing. If the next round of tests prove inconclusive, I might try that. Though, of course, different plants take up lead at different rates. Most, I believe, don’t take up much lead.

  3. We bought our 1939 house from the original owner nine years ago and with it came the original blueprints (very cool!) and specs that it was built to. And the specs actually specify that lead based paint must be used. Sigh…so really no questions about what’s under all our woodwork.

    I hope you get some definitive answers.

  4. If I’m not mistaken, “available lead levels” is the number you’re looking for (no conversion needed). It is impossible to know how much how much lead is actually present due to factors such as phosphorus and pH (and cation exchange capacity for that matter). This helps the buffering capacity of the soil, and as always, a happy healthy plant will uptake less hazardous chemicals from the soil.

    At my job we tell people with Pb levels less than 300ppm not to worry because lead is naturally found in low levels. So, although it is more than you’d like, it really isn’t a big issue at all, especially because I’m sure you have healthy plants to begin with. Between 300-399 we ask people to take a few precautions, such as washing their hands and crops thoroughly before eating (because lead binds to the soil not the plant), and monitor small children when they are outside. Above 400 we ask people to avoid growing leafy greens and root crops (once again, because it is difficult to remove all the soil), among other precautions.

    Although I am glad that you guys brought up the issue of growing in lead contaminated soils, I am a little concerned that you could make people unnecessarily worry about their lead levels. In any event, I wish you guys luck with your endeavors.

  5. Thanks Margi for your input. The Wallace lab report that came back with the high numbers measured plant available lead. The levels were well above 400 ppm if you convert that “available” lead level to total lead. I’m doing more testing to see if there was either an error in that first test or if I hit a hot spot where someone was dumping paint.

  6. If it makes y’all feel any better, the previous owner of the place where I’m living was a sign painter. We just sent hundreds of pounds of rusted-out paint cans to the hazardous waste collection this fall. After our recent rain, I noticed thousands of tiny red and white flecks of paint where one of the scrap signs had decayed years ago. I’m really not sure what to do now, other than isolation and improving the soil health.

    I suppose that won’t make you feel better, but I can commiserate with you, and reiterate for folks to take care of our soil! It takes lifetimes for it to recover from some chemical damage.

  7. We just started gardening last summer and were kind of horrified at all the gardening equipment that had a warning label saying the product “contains lead.” It’s especially prevalent in watering equipment (hoses and attachments like watering wands and spray nozzles). We wound up getting white “RV” nozzles because they were labeled “lead free” and “drinking water safe”. It seems beyond stupid to contaminate the equipment through which water will be passing into gardens.

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