Tuesday, March 14, 2006

lead in the soil

Lots of people have asked me about how we knew we had lead in our backyard soil. In fact, so many people asked me that I wrote an article about it and I've been trying to sell that article for months! However, in the meanwhile, I think lead prevention safety is more important than an article sale, so let me explain. (By the way, if you know of a magazine that would be interested in paying me for such an article, I'm happy to provide it--this is a very important topic)

The area where we now have our garden used to be sort of an old garage/garden shed. It was falling down so we had it pulled down completely. The floor of the "garage" was dirt, so we suspected there might be chemicals in the soil. We mentioned it during a dinner party at our house, and a biologist friend agreed. He works with my husband and had a machine in his lab which tested lead. (I'm purposely avoiding all the names of the pieces of equipment, you don't need to worry about that!) He said he'd be happy to check out a soil sample. Now, his lead tester only indicated a presence of lead. Its lead measurement was not very sensitive, so when it indicated we had lead in the soil right away, we knew we were in trouble.

Our biologist friend contacted someone in the university's Public Health department. We collected samples from all over the yard. In the meanwhile, the husband dug down 8 inches from the dirt floor of the shed, and we had that sample, from 8 inches down, tested too. Our soil varies in its pollution levels--but it is everywhere from 60 to 300 times the legal limit for lead, according to the professor in the Public Health department.

That's dangerous. How did it happen? Well, part of our yard used to have another old house on it. That burned down, and likely the lead paint ashes polluted the soil. The area around the shed probably had its fair number of spills --leaded gas, leaded paint, etc. Finally, our backyard is filled with old trash. When this area of downtown Bowling Green was built, folks used empty lots or backyards to dump their trash. We find completely unbroken old glass medicine bottles, tons of shards of ceramics, old buttons, etc. People have been living here since about 1820? or so, and some Civil War skirmishes happened a block away. That's a lot of trash over time that got dumped here...it would make a great archaeology site.

How does it affect humans? It is extremely dangerous to eat tomatoes (or other vegetables) from this soil, because tomatoes in particularly leach lead from the soil. It would be like eating heavy metal poisoning. I warned the neighbors after we discovered this, but I don't think they were all that surprised...they have trash in their yards, too. That's why we spent the money and built a special area for gardening. It's also the best remediation we can offer in case we sell our house someday.

Does it affect dogs or children? Well, it would if they ingested the soil. We have had Harry's blood tested (for a different problem) and his blood levels were fine. We wipe the dogs' feet off after they've been outside on a muddy day, so they aren't tempted to lick off soil and eat it. (it also keeps the couch cleaner) We don't have any kids yet, but if we did, we'd have to make sure they didn't eat dirt or play too much in this soil. It's a real concern. Mostly, we are cautious. It is extremely difficult to remove this much pollution from the soil, in any case.

Depressing, huh? If you're worried about lead in your soil, ask your local health department, university, or cooperative extension agent for help. You can also send soil samples away to be analyzed...check a magazine like Organic Gardening for places that do that. Do not trust home lead test kits--they aren't nearly precise enough to be scientifically reassuring.

This is why I am so excited about our first garden here. I find the archaeology in the backyard interesting, but I'd far prefer lead-free soil!


Anonymous Anonymous said...

It's amazing what you can find buried in your back yard - I've found tons of glass bottles and a shoe, my neighbor found an entire iron stove/oven!

March 14, 2006 at 12:00 PM  
Blogger Angela said...

How scary, but how neat that you've been able to make your gardening dream come true.

March 16, 2006 at 11:49 AM  

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