These resources were created by the Duke University Superfund Research Center’s Community Engagement Core with the goal of helping garden managers, Extension agents, Extension Master Gardener volunteers, and home gardeners identify, understand, and manage risks associated with chemical contamination that may be present in garden soils. This work was supported through the National Institute of Environmental Health Sciences P42 Multi-project Center Grant program, grant number P42ES010356.
Duke Superfund Community Engagement
What Are Soil Contaminants?
Soil contaminants are naturally occurring or human-made chemicals that can have negative impacts on human, animal, and plant health. Contaminants may be present in soils from past land use activities, such as the historic use of lead paint, pesticides, treated wood, or from being close to heavy traffic areas. Soil contaminants can also be created from industrial activities and can get into soil from spills, runoff, wastewater, or from air emissions that settle onto soil or water
How Can Soil Contaminants Get Into Our Bodies?
Breathing in soil dust
Limit exposure by
- Watering your garden to reduce dust production
- Applying mulch on the soil surface
Direct contact with soil
Limit exposure by
- Wearing gloves when gardening
- Washing hands after gardening
- Avoid tracking soil into your home (leave garden shoes at the door)
Eating contaminated produce
Limit exposure by
- Avoid planting root and leaf crops in contaminated soil
- Peel produce in direct contact with soil
Direct ingestion of soil
Limit exposure by
- Avoid hand-to-mouth activity while in the garden -
- Thoroughly wash all produce
Information on Common Contaminants
| Contaminant | Common Source |
| Arsenic | Treated wood (pre2003), pesticides, coal ash |
| Cadmium | Phosphate fertilizers, tires, vehicles' exhaust |
| Chromium | Nearby industry, well water |
| Diesel Range Organics | Gas stations, traffic, nearby industry, roofing shingles |
| Lead | Historic gasoline & paint use, coal ash, used batteries |
| Mercury | Paint, power plant emissions, thermometers |
| Nickel | Nearby industry, incinerators, on the job in industry, smoking, food (chocolate, soybeans, oatmeal and nuts) |
| PAHs | Vehicle emissions, asphalt, fires |
| Pesticides | Past land use; disposal of pesticide containers |
| PCE & TCE (Solvents) | Dry-cleaners, vapor from soil, well water, nearby industry |
How Can We Reduce Contaminants in Gardens?
- Add organic matter - it can bind contaminants and help to dilute contamination
- Build raised beds, seal the bottom to prevent contact with contaminated soil and drill drainage holes along the sides.
- Replace the contaminated soils
- Avoid planting leafy crops and roots in contaminated soil
- Aim for a pH around 7 (neutral - not acidic or basic)
- If you think your soil may be at risk of contamination, have it tested
How Can Soil Contaminants Affect Our Health?
Soil contaminants can have a variety of impacts. Even low exposure over time can have lasting health effects, including long-term illnesses or impairments. Children and women of childbearing age are more sensitive to soil contamination because of how contaminants affect development.
Video 1: What are Soil Contaminants? Duke University Superfund Research Center personnel, Dr. Elizabeth Shapiro-Garza and Bryan Luukinen, explain what soil contaminants are, review several specific contaminants that can be found in gardens, and more.
Video 2: Exposure Routes and Health Risks. Former N.C. Cooperative Extension Agent Mary Jac Brennan, Duke University Ph.D. student Christina Bergemann, and Duke University Superfund Research Center staff Bryan Luukinen discuss the ways that you can be exposed to soil contaminants from the garden, which populations are more vulnerable, and more.
Video 3: How Can I Learn More About My Garden Site? Former N.C. Cooperative Extension Agents Mary Jac Brennan and Dr. Jeana Myers, discuss the importance of knowing how the land at your garden site was previously used, methods for gaining this information, soil testing options, how to properly sample your soil for testing, and more.
Video 4: How Can I Limit My Exposure in the Garden? Former N.C. Cooperative Extension Agent Mary Jac Brennan, Duke University Superfund Research Center personnel Dr. Elizabeth Shapiro-Garza, Food Bank of Central and Eastern NC Community Garden Manager Lourdes Vinueza discuss some of the best practices to limit your exposure in the garden.
General Information on Soil Contaminants
- 10 Healthy Garden Habits
- How to test your soil and interpret the results
- Well water testing for nickel
- Soil Testing Labs
- Sample Case Study
- Check Your Dirt: Answer the questions to learn about the soil in your garden and best practices to keep you safe.
Where Can I Get More Information?
NC State Extension: Local Extension centers offer classes, tours, and answers
Duke Superfund Community Engagement Core: Connects government agencies, industry professionals, community organizations, K-12 teachers, and others to share research and practical information on environmental health and toxic exposures with the public. Contact superfund@duke.edu
This work was supported through the National Institute of Environmental Health Sciences P42 Multi-Project Center Grant program, grant number P42ES010356.
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