Gardenroots Recommendations & Resources


Calculations of estimated average arsenic daily dose from the three potential exposure routes measured suggested that arsenic exposure was greatest from drinking water (when assuming the primary source of water for irrigation is also used for drinking), followed by incidental soil ingestion, with a relatively small contribution from homegrown vegetable ingestion. When combining greenhouse and home garden data, Asteraceae (lettuce) and Brassicaceae (radish, broccoli, brussels sprouts, kale, and cabbage) families were the top accumulators of arsenic. This finding has been reported in other studies.

Thus, it is recommended that Dewey-Humboldt community members:

  • Test drinking water yearly
  • Test soils prior to gardening
  • Modify gardening behavior to reduce incidental soil ingestion
  • Limit the use of homegrown vegetables from the Asteraceae and Brassicaceae families


List of laboratories conducting soil, plant, feed, or water testing

For water sampling, you may also work with the University of Arizona Cooperative Extension of Yavapai County:

Click to download recommended best practices for gardening handouts:

U.S. Environmental Protection Agency: Iron King Mine Humboldt Smelter Superfund site information