Soil Remediation in Brooklyn

We just tested the garden soil of the Brooklyn Green Show house and the results were a staggering 2000ppm of lead. Considering anything above 400ppm is rated as unhealthy we have a bad situation.

High levels of lead in Brooklyn is a pretty common problem. The back walls and fire escapes were commonly painted in lead paint. Then over time they were stripped of the paint to put a new coat. All that paint went flying into the garden.

If you do that for a couple decades you have a drastic build up of heavy metals in the soil.

Eco Brooklyn provides soil remediation services for Brooklyn gardens. Soil remediation is not hard, but it does involve a lot of hard work. You have do to a lot of digging, lugging and more digging.

The best way we have found is to remove the top foot of soil and get rid of it in a safe way. We then mix the remaining soil in the garden with lots of lime to raise the PH. A university study on the topic of soil remediation found that adding lime to the soil in a soil to lime ratio of 21:1 reduced the danger of lead by 88%.

Along with lime we mix in organic matter like leaves, manure and sod, all of which help bind the lead particles and render them less harmful.

Having significantly reduced the threat of the heavy metals we then add more clean top soil over the old lime/soil mixture. This provides a healthy exposed soil for kids to play in and plants to grow from without ingesting the large amounts of heavy metals that were there previously.

Another way is to plant lots of greens like kale and spinach. They suck up heavy metals very effectively, but alas not so much lead. One study found that 30% of the heavy metals were pulled out of the soil with one season of spinach crops. You then cut the spinach and dispose of the toxic plants. Unfortunately takes time since it could be several years before the soil levels reach safe levels again.

About the author: Gennaro Brooks-Church

3 comments to “Soil Remediation in Brooklyn”

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  1. David Wichern - May 10, 2013 at 7:26 am

    2,000 ppm is huge.

    There is another in-situ remediation method employing a product derived from fish bones. It’s being tried in Oakland, CA. There was an article in the New York Times about it about a year ago. The phosphorus compounds tie up the lead in an insoluble form.

    I’d be a little sceptical about simply adding calcium hydroxide. That will drop the lead out as lead hydroxide, but once the pH is lowered again it will just go back into solution.

    BTW, I’m an analytical/environmental chemist. And, an EPA certified LBP risk assessor. And, I’m not too good to shovel some dirt. Contact me if I might be of assistance. I’m on LinkedIn.

  2. Greenscaper - May 1, 2010 at 11:03 am

    Hi Gennaro, Sub-irrigated planters (SIPs) are an excellent alternative to in-ground gardening here in Brooklyn and most other cities with widespread occurrences of contaminated soil.

    SIPs can be of virtually any size and shape including planter boxes and raised beds. I have more than 30 years of experience with SIPs and blog about urban greenscaping using modern water conserving methods that do not require tillable land. I’d be glad to answer any questions you may have. I live in Bay Ridge. Bob Hyland

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