We received soil test results last month from the Environmental Sciences Analytical Center at Brooklyn College and have finally gotten some information about what the results mean for our community garden.
So what does it all mean?
First of all, heavy metals are naturally-occurring elements, present in all soil. But in cities, the accumulation of heavy metals is more pronounced — primarily from car exhaust. After particles are released into the air, they always settle back down into the ground.
Second, ingesting heavy metals is to be avoided — especially for pregnant women and children (that’s why families need to be careful about chipped lead paint in their homes). Being exposed to too much of one metal can lead to health problems, but with some simple precaution it is unlikely you will be exposed to unhealthy levels.
One of our gardeners forwarded a link from the University of Minnesota with some very useful information about lead in urban gardens.
The results for the soil in our new garden show average levels of heavy metals for New York City. And the level of lead, even though average for the city, require some precautions. Because plants do not take up significant quantities of heavy metals, the real danger is ingesting the soil itself, so you should wear gloves when working in the garden, or wash your hands afterwards. Anything edible that you harvest should be washed thoroughly. (If you are particularly nervous about all these numbers, you will probably decide to not eat any root vegetables or leafy greens from the garden.)
Probably the best piece of advice is suitable for young children, whether they are in the garden or just sitting on a piece of earth anywhere in the city: don’t eat the dirt.
If our community garden is to grow and thrive with edible harvests we can all feel are safe, we should probably consider constructing raised beds next year filled with uncontaminated, organic soil. Such a project would of course require some work and money. A composting program for the garden would contribute to the health and maintenance of the soil. Gardeners who feel strongly about these issues should be ready to contribute to this effort, and lobby the Board of Directors for assistance.