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Soil Contaminants

Learn About soil contaminants

Lead, arsenic and cadmium are common urban soil contaminants. Reduce exposure to these contaminants by learning more about them.

Lead is the most common heavy metal contaminant in soil. It is more prevalent in older, larger cities with an industrial history, current or former structures built before 1960 where lead based paint was used, or along an old roadToddler playing in mud. When lead enters the body every organ can be impacted. Organs particularly damaged include the brain, heart, and kidneys. Children are especially susceptible to health impacts from lead exposure.

Most urban soils do not have harmful levels of lead, but it is important to test your soils because soil lead is not visible nor does it produce an odor. Soils with very high levels of lead may still grow healthy, vigorous plants. Learn more about lead in soil here and learn about testing for lead here. Arsenic and cadmium are less common urban contaminants and are more likely to occur on sites with industrial histories. Arsenic may also be present where pre-2000s treated wood was used. You can learn more about arsenic here and cadmium here.


Have you heard conflicting things about urban soil contaminants: that all urban soils are contaminated and not safe for gardening, or that sunflowers help reduce soil lead, or that raised-beds are a cure-all for urban gardens? Check out our Myths and Facts page to learn the truth about these rumors! To dive deeper into the science behind soil contamination, check out the Risk and Contaminated Soil page and the Glossary


Soil testing is recommended for garden sites which are:

  • Urban
  • Formerly industrial
  • Within 10 feet or a current or former structure built before 1960
  • Have an unknown history

If this sounds like your site, learn more about soil testing, sampling, and interpreting results here.



If testing reveals contamination on your site, you still may be able to grow. Learn about managing contaminated soil for safer gardening here.