For more information on Perchlorate, please contact:John Quander
Technology Assessment Branch
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Policy and Guidance
- Policy and Guidance
- Chemistry and Behavior
- Environmental Occurrence
- Detection and Site Characterization
- Treatment Technologies
- Conferences and Seminars
- Additional Resources
Perchlorate has been detected in drinking water supply systems across the country. The chemical was placed on the EPA Office of Water's Contaminant Candidate List in 1998. The drinking water Contaminant Candidate List (CCL) is the primary source of priority contaminants for evaluation by EPA's drinking water program. The Safe Drinking Water Act (SDWA), as amended in 1996, requires EPA to publish a list of contaminants every five years that are not subject at the time of publication to any proposed or promulgated national primary drinking water regulations. Contaminants on the CCL are known or anticipated to occur in public water systems and may require regulations under SDWA.
EPA has established an official reference dose (RfD) of 0.0007 milligrams of perchlorate per kilogram of body weight per day. This level is consistent with the recommended reference dose contained in the National Academy of Science's report of January 2005, Health Implications of Perchlorate Ingestion. A reference dose is a scientific estimate of a daily exposure level that is not expected to cause adverse health effects in humans. The EPA Integrated Risk Information System (IRIS) summary for perchlorate and perchlorate salts presents the Agency's current thinking on this subject. The RfD, which represents a preliminary estimate of a protective health level but is not a drinking water standard, will be used in EPA's ongoing efforts to determine if regulation of perchlorate in drinking water would represent a meaningful opportunity for reducing risks to human health.
EPA's new perchlorate RfD translates to a Drinking Water Equivalent Level (DWEL) of 24.5 ppb. A Drinking Water Equivalent Level, which assumes that all of a contaminant comes from drinking water, is the concentration of a contaminant in drinking water that will have no adverse effect. Because a margin of safety is built into the RfD and the DWEL, exposures above the DWEL are not necessarily considered unsafe.
Perchlorate compounds do not have reportable quantities under the Federal Water Pollution Control Act (Clean Water Act), as amended, or the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) , as amended; however, EPA's Superfund cleanup program, which administers CERCLA, has issued guidance (415K/3pp/PDF) based on the new RfD. Perchlorate compounds also are not listed in the compounds covered by the Emergency Planning and Community Right-to-Know Act of 1986 (EPCRA). Though not listed as hazardous wastes under the Resource Recovery and Conservation Act (RCRA), as amended, they may fall under its definition of reactive chemicals.
In July 2006, Massachusetts became the first state in the nation to promulgate drinking water and waste site cleanup standards for perchlorate, setting the standard at 2 ppb. On October 18, 2007 California became the second state to set a perchlorate drinking water maximum contaminant level (MCL). The California standard is 6 µg/L.
EPA Sets Reference Dose for Perchlorate
U.S. EPA press release, 18 Feb 2005.
National Academy of Sciences (NAS) Review of the "Health Implications of Perchlorate Ingestion"
U.S. EPA, National Center for Environmental Assessment.
Perchlorate in Drinking Water
California Department of Public Health
Assessment Guidance for Perchlorate
U.S. EPA, Office of Solid Waste and Emergency Response. 3 pp, 26 Jan 2006.
This guidance replaces previous Office of Solid Waste and Emergency Response guidance regarding perchlorate under the National Oil and Hazardous Substances Contingency Plan, 40 CFR Part 300. Following the National Academy of Sciences' National Research Council review, EPA adopted a reference dose (RfD) for perchlorate of 0.0007 milligram/kilogram-day (mg/kg-day), and this guidance applies that to EPA's CERCLA program. This RfD leads to a Drinking Water Equivalent Level (DWEL) of 24.5 micrograms/liter (ug/L) or 24.5 parts per billion (ppb).
DoD Perchlorate Handbook
U.S. DoD, Environmental Data Quality Workgroup. 73 pp, August 2007.
This handbook was developed to assist DoD facilities in complying with current DoD policy governing perchlorate sampling and testing activities for both environmental restoration/cleanup and compliance monitoring programs.
Department of Army Guidance for Assessing Potential Perchlorate Contamination
U.S. DoD, Office of the Under Secretary of Defense. 25 pp, 11 June 2004.
DoD guidance on perchlorate sampling, testing, and documentation.
Elaboration on the Prioritization Protocol for Perchlorate Impacts
U.S. DoD and CalEPA, 7 pp, Sep 2004
This protocol aids DoD services and state agencies in prioritizing perchlorate sampling activities where such activities occur unplanned and unbudgeted. The criteria are (1) the potential for past perchlorate use at the site and (2) a drinking water well with >6 ppb perchlorate within 5 miles. See the original protocol, p 22-30, in ASTSWMO's 2005 Perchlorate Issues Document.
Environmental Contamination: Department of Defense Activities Related to Trichloroethylene, Perchlorate, and Other Emerging Contaminants
U.S. General Accountability Office, Washington, DC.
GAO-07-1042T, 18 pp, 2007
While DoD has clear responsibilities to address TCE because it is subject to EPA's regulatory standard, DoD's responsibilities are less definite for perchlorate due to the lack of such a standard. This report describes the activities DoD has undertaken in response to different state perchlorate action levels and requirements. The 2006 Policy on DoD Required Actions Related to Perchlorate established 24 ppb as the current level of concern for managing perchlorate until the promulgation of a formal standard by the states and/or EPA.
Perchlorate Policy Update
ASTSWMO Federal Facilities Research Center, Emerging Issues Focus Group, 16 pp, 2011
This Perchlorate Policy Update supplements ASTSWMO's 2005 Perchlorate Issues Document and provides information on state and federal policies, guidance, and resources specific to assessing and remediating perchlorate contamination.
Policy on DoD Required Actions Related to Perchlorate
Office of the Under Secretary of Defense
3 pp, January 26, 2006
Sets action level for perchlorate at 24 ppb and specifies monitoring programs for sampling and testing (e.g. NPDES and drinking water).
Report to the Congress: Perchlorate in the Southwestern United States
U.S. DoD, The Office of the Secretary of Defense, Under Secretary of Defense (Acquisition, Technology & Logistics). 155 pp, Jul 2005.
Alabama Risk-Based Corrective Action Guidance Manual
Alabama Department of Environmental Management, 203 pp
Alaska 18 AAC 75 Oil and Other Hazardous Substances Pollution Control
Alaska Department of Environmental Conservation
Public Review Draft September 19, 2007, 33 pp
Contains cleanup levels for perchlorate.
Arizona Notice of Final Rulemaking Title 18. Environmental Quality Chapter 7. Department of Environmental Quality Remedial Action
Arizona Department of Environmental Quality
Contains soil cleanup levels for perchlorate.
California: Perchlorate in Drinking Water
California Department of Health Services, Division of Drinking Water and Environmental Management.
The California Department of Health Services uses a perchlorate notification level to protect consumers, as it has since 1997. The notification level for perchlorate is 6 micrograms per liter (µg/L). In March 2004, California's Office of Environmental Health Hazard Assessment established a public health goal (PHG) of 6 µg/L.
DRAFT 2006 Guidance for Assessing and Reporting Surface Water Quality in Texas (June 27, 2007), In Compliance with Sections 305(b) and 303(d) of the Federal Clean Water Act
Texas Commission on Environmental Quality
This is a guide for assessing surface water (e.g., sampling, classification) that includes perchlorate and lists the action level at 22 µg/L.
Perchlorate in Drinking Water: A Science and Policy Review [California]
Richard J. Bull, A.C. Chang, C.F. Cranor, R.C. Shank, and R. Trussell.
Urban Water Research Center, University of California at Irvine, 59 pp, 2004.
Massachusetts Drinking Water Supply Information: Perchlorate
Bureau of Resource Protection
Massachusetts Department of Environmental Protection
Maximum Contaminant Recommendation for Perchlorate
New Jersey Drinking Water Quality Institute
Nebraska Voluntary Cleanup Program Remediation Goals
Nebraska Department of Environmental Quality
Nevada Drinking Water Standard for Perchlorate
Nevada Division of Environmental Protection
Screening for Environmental Concerns at Sites with Contaminated Soil and Groundwater, Volume 1: Summary Tier 1 Lookup Tables
Hawaii Department of Health Environmental Management Division
Contains Environmental Action Level tables.
Perchlorate Screening Values
Workshops on Perchlorate Best Management Practices
California Department of Toxic Substances Control.
DTSC Reference Number: R-2005-03, 2006
The California Department of Toxic Substances Control (DTSC) conducted public workshops in August, September, and November 2005 to solicit input on the development of draft regulations for perchlorate best management practices (BMPs). The meeting materials and comments are available on the DTSC website and include a series of draft background papers that provide information on the chemistry and toxicology of perchlorate, sources of perchlorate in the environment, perchlorate-containing products, manufacture and distribution, known perchlorate sites and cleanup operations, and the implications of perchlorate contamination on California's water supply. The DTSC adopted the Perchlorate BMP regulations on December 31, 2005, and the regulations became effective July 1, 2006, as "Best Management Practices for Perchlorate Materials" (Title 22, California Code of Regulations, Chapter 33)
State Perchlorate Advisory Levels
U.S. EPA, Federal Facilities Restoration and Reuse Office, April 20, 2005.