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Soil Test for Lead

The soil should be sampled by taking 6 to 12 sub-samples from the area of concern. For play areas, sample to the depth to which the child has been exposed, usually one half to one inch depth. For garden soils, the sampling depth should be from the surface 3 to 4 inches. Lead does not move to any great extent in soils and unless mixing occurs, it generally stays concentrated near the surface. Mix the sub-samples thoroughly in a clean plastic pail, remove about one cup, and submit to the laboratory in a clean container.

What to Look for in Lead Test Results

If soil exposure to children is not of concern, then plants can be safely eaten from soils with lead levels of up to 300 mg/kg for leafy and root type vegetables, and 500 mg/kg for fruits and vegetables where the fruiting parts are eaten.If young children play in the area of concern and your soil test is higher than 100 mg/kg, it is suggested that the children have a blood test for lead. Contact your local health department or private physician for additional information. 

Precautions for Garden Soils

To minimize absorption of lead by plants, a number of control measures may be taken:

• 1. Maintain soil pH levels above 6.5 by limiting when necessary. Lead is less available to plants at higher pH levels.
• 2. Add organic matter (e.g. compost, manure, etc.) to your soil . Organic compounds bind lead and make it less available to the plant.
• 3. Locate your garden away from busy streets and older buildings.