Interpreting Your Soil Test Results
If you have submitted soil samples for Indiana University to test, the following information will help you interpret your results to minimize your exposure to lead.
- What Is Lead?
- Exposure to Lead
- Why Is Lead Hazardous to Humans?
- Contextualizing Your Soil Lead Levels
- How to Reduce Your Exposure to Lead in Soil
- How to Reduce Your Exposure to Lead in Dust
- Additional Resources
What Is Lead?
Lead is a naturally occurring heavy metal. Because it is abundant and cheap, lead has been used in construction, plumbing, batteries, bullets and shot, weights, solders, pewters, fusible alloys, white paints, leaded gasoline, and radiation shielding (for example, when the dentist takes x-rays, you must wear a lead shield). Lead was phased out of automobile gasoline in 1996 and removed from paint in 1978.
Background levels of lead in soil range from 10 to 79 parts per million (ppm). In Indiana, the average is around 30 ppm.
Urban soils are often higher.
Exposure to Lead
People often associate lead exposure with contaminated water; however, for most people around the world, the dominant exposure pathway for lead is through dust. Lead found in house dust comes from various sources, inside and outside the home. Lead occurs naturally in the environment in small amounts. However, leaded gasoline, lead-based paint, agricultural pesticides, and industrial pollution have all artificially increased lead levels in soil, especially near urban centers.
Not all urban homes will have high lead in their soil/dust, but if you live in a city, being aware of the risks and getting your soil/dust tested are essential first steps. Rural homes may have lead-contaminated soil and dust as well. For example, if your home was built before 1978, it may contain interior and exterior lead-based paint. Furthermore, rural and suburban homes constructed on land formerly used for agriculture, especially fruit orchards, may have soil contaminated by lead-based pesticides.
Lead is equally toxic when inhaled as dust or ingested in water. It accumulates in bones and is distributed throughout the blood to most organ systems, including the brain, where it acts as a neurotoxin. The U.S. Agency for Toxic Substances and Disease Registry (ATSDR) considers lead so toxic that they list no acceptable Minimal Risk Level (MRL) for oral (water) or particulate inhalation (dust).
Why Is Lead Hazardous to Humans?
According to the Centers for Disease Control, no level of lead is safe in humans, especially children.
Lead-based paint is especially hazardous to young children because of its sweet taste. As older lead-based paint ages and flakes, children may be tempted to eat the flakes because of this sweetness. Even low levels of lead exposure during early childhood can result in lifelong reduced IQ, decreased attention span, decreased impulse control, and increased antisocial behavior. People who experience childhood lead poisoning make less money over their lifetime and are more likely to be incarcerated than their peers.
Find additional information about lead as an environmental contaminant at:
ATSDR Toxic Substance Report for Lead (https://bit.ly/cdc-lead-toxic-substances)
Contextualizing Your Soil Lead Levels
If you have elevated levels of lead in your soil, determining how you want to interact with your soil will guide your next steps. Click on the heat arrow below to download a PDF of actions you can take to protect yourself and your family when interacting with your soil. Then read on for tips on reducing your exposure to lead in soil and dust.