Arsenic is a naturally-occurring metal and is present widely in Delaware soils at concentrations up to 45 parts per million (ppm). In addition to occurring naturally, arsenic in soils can come from:
• historic uses at tanneries and at various industries, such as foundries;
• from pesticides before synthetic organic pesticides were available;
• from fertilizer and potting soils;
• from chicken litter; and
• from arsenic-treated wood .
Arsenic contamination is also commonly associated with orchards and golf courses due to the application of arsenic-based herbicides and pesticides. DNREC conducted a comprehensive evaluation and public outreach effort from 2005 to 2007 to develop an appropriate default background concentration for Arsenic. Based on the evaluation and public comments, the default background concentration, to be used sometimes as a cleanup standard for Arsenic-impacted sites, was set at 11 parts per million (ppm) by DNREC Division of Air and Waste Management policy dated February 2007.
The Department of Natural Resources and Environmental Control (DNREC) has been working on cleanup of contaminated sites since 1980. Arsenic is one of the more complex contaminants found at old industrial sites because it can be hazardous at relatively low concentrations and requires careful efforts to protect public health and the environment, and because it is a naturally-occurring element found as part of the complex geology of the Mid-Atlantic.
For more information on the cleanup of contaminated sites, please contact Kathy Stiller, Manager of DNREC’s Site Investigation and Restoration Branch at (302) 395-2600 or Kathleen.Stiller@state.de.us .
Arsenic Policies and Standards
Arsenic Reports and Information
