Is your soil SAFE?

It certainly comes to no suprise to us that those of us living in and around Chicago reside in an urban environment. While that means that we have access to good public transportation systems and ample supplies for all of our wants nearby,it also means that we have some other issues that we have to acknowledge and deal with. I was leading a group of teachers yesterday in a soil sampling exercise and they were mighty surprised to hear what I had to say. 

I was not delving into the results of a typical soil test - nutrients, pH level, etc. I was discussing testing for toxins -- specifically lead (a heavy metal). If you live in our area, chances are that you should be testing for lead. Lead is considered an indicator metal (meaning that if it is present at high amounts, you may have other types of contamination) and is a neurotoxin. Metals such as lead are usually taken in by ingestion or inhalation. Anyone who is out in a garden on a hot, windy day knows that "dirt" is often blowing around and we end up breathing it in and it covers our food. Children are the most affected by these contaminants, which affect physical development and our brains. We usually think what we grow at home to eat is healthy, but it may not be. In order to know for sure, get your soil tested.

 We have a great soil testing lab here on the west side of Chicago called Stat Analysis. They charge $8.00 per lead test and will get you the results to your test in 72 hours. A & L Great Lakes in Indiana has a great lead fact sheet that will tell you more. Wondering just how to take a good soil sample?

• Timing is important (test before you begin to garden!).
• Use clean equipment.
• Sample each area separately.
• Dig deep enough.
• Mix samples well.
• Mark container appropriately.

What do the results mean? When reading your lead test results, they will be listed in parts per million (ppm) or mg/kg:
 0-35 ppm the natural level of lead found in soil

75 ppm the Canadian maximum level of lead in the soil that adults or children eat produce from

100 ppm the EPA established maximum amount of lead in soil that youth should be eating produce from

400 ppm the EPA established maximum amount of lead in soil that adults should be eating produce from

400 ppm+ toxic for adults and children – soil should not be gardened  directly in

Ok, so say your results come back looking something like mine did - at 1100 ppm (off the charts if you look at what the EPA has to say).  Do you stop gardening all together and cover your backyard in concrete? Heck no!

Here is what you can do about contaminated soil…

• Install raised beds to raise vegetables (adding new soil and a lining between the old and new soil)
• Grow perennials only
• Add a protective layer of mulch, stone or grass that will limit dusting of soil (for inhalation)
• Clean body, clothing and shoes to ensure that lead particles from the soil are not brought into the home or school
• Add compost or other organic material (which bind heavy metals like lead and keep them from moving)
• Cap the soil with clay
• Remove the soil (an expensive venture as you must responsibly dispose of the contaminated soil in hazardous waste site)

There is a lot to learn about lead in your soil. It is important to be informed and garden safely. Then we can know that the food that we are eating, growing, and sharing with our neighbors really is good for us!