Soil can contain hazardous amounts of asbestos, lead, or other heavy metals. Don't risk your children’s heath! Find out if your soil is safe.
Children under the age of six are especially vulnerable to lead poisoning, which can affect the developing nervous system and other organs. Lead may be ingested when children place objects containing lead in their mouths, or when dust is inhaled. Fruits and vegetables grown in lead-contaminated soil also pose a risk. There is no known safe level of lead in the body.
Lead can find its way into soil from lead-based paint dust, leaded gasoline exhaust, or other sources. Lead-based paint was banned in the US in 1978, but millions of homes built before that still have the toxic coating. Leaded gasoline was banned in 1986, but lead can stay in the soil for a thousand years. The only way to know whether your soil has lead is to have it tested. We recommend lead testing if your home was built before 1978 or it is near a high-traffic road.
How to take samples
You can send samples of your suspect soil to MACS Lab for analysis. We suggest taking a sample in any areas where children play, and from any vegetable garden or orchard. If your house has a dripline where water runs off the roof (no gutters), we also recommend taking a sample at the dripline of the house. We need one to two tablespoons of soil for each sample. Take the sample from the top layer of the soil, because that is where most of the contamination, if any, would be.
Place the soil into a zip lock type food storage bag and label it so that you know exactly the location it came from. Put each area’s sample into a separate bag for separate testing.
If you prefer to have a professional visit your house to sample the soil, we recommend choosing a lead-safe certified contractor.
How to send samples
Download our Chain of Custody form and fill out the highlighted fields and any other relevant information. The analysis costs $37.50 per sample. When you are ready, click here for instructions on submitting your samples.
Interpreting your results
Your report is usually sent in two business days. (You can order the results within 4 hours of receipt for an additional charge.) The results for your samples are on the first page. (The other pages are for quality assurance purposes and you can ignore them.) The column labeled "Lead ppm" tells you the parts per million (by weight) of lead in your sample. If you see the less-than symbol “<”, it means there was too little lead to detect.
Lead hazards are regulated by the US Environmental Protection Agency and may also be regulated by your state. The EPA defines bare soil as hazardous if it has 400 ppm or more of lead in play areas, or 1200 ppm or more of lead elsewhere in the residential yard (per 40 CFR Part 745). If your soil has more lead than this, you should consult the EPA web site or other resources for measures you can take to reduce exposure to the lead.
Certain heavy metals are toxic. These metals can find their way into soil from the disposal of pesticides, paints, and other waste. Old orchards may have used insecticides containing arsenic. Areas near industrial sites or mining waste are also at risk. Some heavy metals, including arsenic, can occur naturally. As with lead, exposure to other heavy metals from soil can occur by ingestion, by inhaling dust, or from fruits and vegetables grown in contaminated soil.
We can test your soil for any or all of the following metals. All are toxic to humans except as noted. The cost is $37.50 per metal, or $150.00 for all 17.
- Copper (toxic at high levels)
- Selenium (certain forms are toxic)
- Silver (toxic to algae and fungi)
- Zinc (toxic to plants and fish at high levels)
To send a soil sample to us for testing, see “How to take samples” above. Then download our Chain of Custody form and fill out the highlighted fields and any other relevant information. Be sure to indicate on the chain of custody which of the above metals you want tested. When you are ready, click here for instructions on submitting your samples.
Interpreting your results
Your report is usually sent in three business days. The report contains three sections. The first section, labeled “Analysis Report”, has the results for your samples. (The other two sections,“Analytical Sensitivity” and “Quality Control Report”, are for quality assurance purposes and you can ignore them.) There is a column for each sample. The number in the column tells you the parts per million (by weight) of each metal in the sample. If you see the less-than symbol “<”, it means there was too little of that metal to detect.
The US EPA and various public health agencies have published guidelines for “safe levels” of certain metals in soil; unfortunately these organizations do not always agree on what is safe. We recommend this site on heavy metals and gardens for information on what levels are safe and how to manage metals in your soil.
Soil can be contaminated by asbestos-containing building materials such as roof shingles, or from certain naturally-occuring minerals. Asbestos in soil is a risk to health if the asbestos is disturbed, becomes airborne, and is inhaled. Asbestos is not absorbed by garden plants, but gardening activity disturbs the soil and is likely to release asbestos into the air.
To have your soil tested for asbestos, see “How to take samples” above. To avoid releasing asbestos into the air, you should dampen the soil slightly before disturbing it. Then download our Chain of Custody form and fill out the highlighted fields and any other relevant information. The analysis costs $35 per sample. When you are ready, click here for instructions on submitting your samples.
Interpreting your results
Your report is usually sent in two business days. The report will clearly say whether or not the sample has any detectable asbestos. The EPA has not established any safe level of asbestos in soil.