Is your soil safe?
Is the soil in your garden contaminated? If so, is it okay for you or your kids to be working in the soil? Will the vegetables you grow there be safe to eat?
The answers to these questions are complicated, and we don’t have all the information we would like. People may be concerned about contaminants in their soil because they’ve had a community garden plot for years with soil that has never been tested, or they may be starting a new community garden, or there may be children working in the garden. Their first question is: Should I test my soil?
The answer isn’t simple, You may need to do some research to find out what possible sources of contamination exist now and existed in the past. Is your community garden near a toxic waste site or near an industrial site that may be using harmful chemicals? How was the site of your garden used in the past? Was there a house on that spot that contained lead paint? Were decks or swing sets on the property built from pressure treated wood? Even former farmland and orchards can contain contaminants– arsenic and lead were once used as pesticides.
Soil contamination may be more likely if the site has had any of the following: lead paint, high vehicle traffic, use of fertilizers or pesticides, industrial or commercial activity, treated lumber, petroleum spills, automobile or machine repair, junk vehicles, furniture refinishing, fires, landfills or garbage dumps.
There’s no single soil test that will pick up all contaminants, so you need to determine what contaminant or contaminants are likely to be in your soil, then test specifically for those. In addition to metals such as lead, researchers are also concerned about polycyclic aromatic hydrocarbons (PAH), which are byproducts of burning and can cause many health problems, including cancer.
Contaminated soil can affect us in several ways. We might touch the soil and bring our hands to our mouth, ingesting the soil. We might breathe in the dust.
The food we grow in contaminated soil could become contaminated. However, Shaylor noted that contaminated dust on leafy vegetables or root vegetables is more of a concern than contaminants taken up and into the plant. The steps you take in your garden depend on the results of your testing and how you want to use your garden. A few of these steps include:
Top dress the garden area with clean materials such as uncontaminated soil, compost, manure or peat moss, or incorporate these materials into your soil. If you have a square yard of soil and add a square yard of compost, you’ve cut the contamination in half. Because organic matter in compost breaks down over time, incorporate new material often.
Use raised beds. A layer of landscape fabric will prevent plant roots from entering the contaminated soil below the bed. Avoid using railroad ties, telephone poles and pressure-treated lumber to build your beds because they contain chemicals that can migrate into the soil. You should use uncontaminated soil and compost. However, Shaylor noted that there aren’t any regulations governing commercial soil products and what you buy may not have been tested for contaminants.
Mulch walkways and other areas to reduce dust and soil splashback onto crops, or maintain healthy grass or other ground cover.
Create a barrier to separate underlying soil from children’s play area surfaces. Consider laying down landscape fabric and put clean play materials such as sand or wood chips on top.
Adjust soil pH to near neutral. At lower pH levels (acidic soil), lead is in a more available form for plants and it’s easier for plants to take up the contaminant.
Wash vegetables thoroughly and peel root vegetables.
For more information, feel free to contact Cleanovator for a in-depth evaluation of your situation and customize the testing you need for your soil.
