If you’re worried your soil is contaminated, get it tested
By LEE REICH
Dampening my friend Dan’s excitement about moving to a new home was one nagging fear: Before being developed for homes about 45 years ago, the site had been an orchard.
Orchards are notorious for being doused repeatedly with toxic sprays. Were residues still lingering in the soil?
Throughout the early part of the 20th century, apples and other crops were commonly sprayed with lead arsenate, and neither lead nor arsenic readily washes out of soils. Synthetic pesticides, such as DDT, are other potential contaminants on agricultural sites.
Agriculture is not the only culprit responsible for contaminating soil. Lead can rise to excessive levels near old homes from lead-rich paints that were scraped or flaked off into the soil, and near heavily trafficked areas.
DANGERS OF CONTAMINATED SOIL
These toxic materials can be absorbed into plants, but often do most harm when contaminated soil is breathed in or ingested. Soil tracked indoors or carried in on clothing can eventually become airborne dust. Children frequently put dirty hands in their mouths and sometimes eat soil, and adults and children might ingest soil adhering to root crops.
Soil contamination by synthetic pesticides such as DDT, which came into use after World War II, is generally not of concern in backyard situations. Direct ingestion or breathing in soil particles generally provides less exposure than residues on foods. DDT and related compounds do persist a long time in the environment, but more modern synthetic pesticides break down relatively quickly.
IF A SITE SEEMS SUSPECT, TEST IT
I suggested to Dan that he have his soil tested. Soil tests usually are used to optimize fertilizer use but can also be done to test for contaminants. Contact a university or private soil testing laboratory, and then expect to wait from a few days to a few weeks to receive the results.
Most soil test reports include a recommendation for amounts of limestone or sulfur to add to adjust soil acidity. Soil acidity not only influences a plant’s uptake of nutrients but also its uptake of lead, arsenic and other potentially hazardous metals.