Naturally occurring perchlorate is produced through atmospheric  processes and then settles on surface water or land as precipitation or dry  deposits. EPA has the authority to regulate contaminants, such as perchlorate, in  public drinking water systems. However, perchlorate has been found  at varying levels across the nation in water and the food supply and is  known to come from a variety of sources. Although there has been no nationwide sampling for perchlorate recently,  nationwide sampling under EPA’s UCMR 1, which occurred between 2001  and 2005, detected perchlorate at or above 4 parts per billion in at least  one sample in approximately 4.1 percent of the public drinking water  systems tested. Sampling conducted at various times by federal agencies, including DOD,  NASA, DOE, and EPA, has detected perchlorate in drinking water,  groundwater, surface water, soil, and sediment. Specifically,    DOD reported perchlorate detections at 284 of its installations, or almost  70 percent of the 407 installations sampled from fiscal years 1997 through  2009, with detections ranging from less than 1 part per billion to 2.6 million  parts per billion. NASA reported the highest detection of 13,300 parts per billion  in groundwater in 2002 at the Jet Propulsion Laboratory in California. Food and Drug Administration and Other Researchers Have Found Perchlorate in a Variety of Foods at Low Concentrations

In addition to finding perchlorate in water and soil, Food and Drug  Administration (FDA) and other researchers have found perchlorate in a  variety of foods. Certain foods, such as tomatoes and spinach, had higher  perchlorate levels than others. While the Likely Sources of Some Perchlorate Detections Are Known, Sources of Others Can Be Difficult to Determine

According to the perchlorate researchers we spoke with, concentrations  of perchlorate at or above 100 parts per billion are generally the result of  activities involving man-made perchlorate, such as the use of perchlorate  in manufacturing or as a solid rocket propellant. Researchers we  contacted told us that perchlorate detected at levels above 100 parts per  billion is generally man-made and is limited to a specific area. Concentrations of perchlorate below 100 parts per billion can result from  the use of man-made perchlorate, natural processes, or the use of fertilizer  containing naturally occurring perchlorate. According to DOD,  DOE, and NASA officials, by complying with current federal and state  waste disposal laws and regulations, they have lessened perchlorate  releases. According to DOD’s current perchlorate policy, when detections in water  equal or exceed an identified threshold level—currently EPA’s health  advisory level of 15 parts per billion or a stricter state standard if identified  by DOD—DOD is to conduct further investigations to determine whether  additional action is warranted. Our analysis of data from DOD’s perchlorate database showed that  military service officials had decided to take action beyond initial  sampling at 48 of the 53 installations with perchlorate detections above 15  parts per billion. Finally, according to DOE officials, the agency has sampled and detected  perchlorate at all five facilities where there was a potential for  contamination based on the use of the chemical in high explosives  research, development, and testing. DOE is continuing to monitor the  levels of perchlorate in groundwater, according to agency officials. For example, in 1999, DOD’s  Army Research, Development and Engineering Command began  developing perchlorate substitutes for use in weapons simulators, flares,  and rockets, according to DOD officials. In the Absence of a Federal Standard, Some States Have Set Drinking Water Standards and Guidance Levels for Perchlorate

In the absence of a federal regulatory standard for perchlorate in drinking  water, California and Massachusetts have adopted their own standards. California  promulgated its drinking water standard for perchlorate of 6 parts per  billion in 2007, and Massachusetts set a drinking water standard of 2 parts  per billion in 2006. Several States Have Issued Guidance Levels for Perchlorate

In addition to the regulatory standards set by California and  Massachusetts, at least 10 states have established for various purposes  guidance levels for perchlorate ranging from 1 part per billion to 18 parts  per billion for drinking water and from 1 part per billion to 72 parts per  billion for groundwater. Key contributors to this report are listed in  appendix V.

Appendix I: Objectives, Scope, and Methodology

This report examines (1) what is known about the extent to which  perchlorate occurs in the nation’s water and food supply and its likely  sources; (2) what actions the Department of Defense (DOD), the National  Aeronautics and Space Administration (NASA), and the Department of  Energy (DOE) have taken to respond to or lessen perchlorate releases;  and (3) the actions states, such as California and Massachusetts, have  taken to regulate perchlorate. To determine what is known about the extent of perchlorate occurrence in  water and other media at DOD, NASA, and DOE installations and facilities,  we obtained data on perchlorate occurrence at facilities owned or  managed by these agencies. 3.
Why GAO Did This Study

Perchlorate is both a man-made and naturally occurring chemical. It is used in rocket fuel, explosives, fireworks, and other products. Naturally occurring perchlorate is produced through atmospheric processes and then settles on surface water or land. Perchlorate can disrupt the uptake of iodide in the thyroid, potentially interfering with thyroid function and negatively affecting fetal and infant brain development and growth. As of June 2010, there is no federal regulatory standard for perchlorate in drinking water, and the Environmental Protection Agency (EPA), which has the authority to regulate contaminants in public drinking water systems, had not determined whether to establish one. The Department of Defense (DOD), the National Aeronautics and Space Administration (NASA), and the Department of Energy (DOE) are the primary federal users of perchlorate. GAO was asked to examine (1) what is known about the extent to which perchlorate occurs in the nation's water and food supply and its likely sources; (2) what actions DOD, NASA, and DOE have taken to respond to or lessen perchlorate releases; and (3) what actions states, such as California and Massachusetts, have taken to regulate perchlorate. To address these questions, GAO analyzed data from EPA, DOD, NASA, and DOE, reviewed agency documents, and interviewed federal and state officials, researchers, and others.

What GAO Found

Perchlorate has been found in water and other media at varying levels in 45 states, as well as in the food supply, and comes from a variety of sources. EPA conducted one nationwide perchlorate sampling, between 2001 and 2005, and detected perchlorate at or above 4 parts per billion in 160 of the 3,865 public water systems tested (about 4.1 percent). In 31 of these 160 systems, perchlorate was found above 15 parts per billion, EPA's current interim health advisory level. Sampling by DOD, NASA, and DOE detected perchlorate in drinking water, groundwater, surface water, soil, and sediment at some facilities. For example, GAO's analysis of DOD data showed that perchlorate was detected at almost 70 percent of the 407 installations sampled from fiscal years 1997 through 2009, with detections ranging from less than 1 part per billion to 2.6 million parts per billion. A 2006 Food and Drug Administration study found perchlorate in 74 percent of 285 food items tested, with certain foods, such as tomatoes and spinach, having higher perchlorate levels than others. According to researchers, concentrations of perchlorate at or above 100 parts per billion generally result from activities involving man-made perchlorate, such as the use of perchlorate as a rocket propellant. Lower concentrations can result from the use of man-made perchlorate, atmospheric processes, or the use of fertilizer containing naturally occurring perchlorate. According to DOD, NASA, and DOE officials, the agencies have sampled, monitored and, at several sites, begun cleaning up perchlorate. When DOD detects perchlorate at or above threshold levels--currently 15 parts per billion for water--DOD is to investigate further and may take additional actions. DOD has taken actions beyond initial sampling at 48 of the 53 installations with perchlorate detections above 15 parts per billion. NASA is in the midst of a cleanup at the Jet Propulsion Laboratory in California and is monitoring the level of perchlorate in groundwater at three other facilities. In addition, DOE is cleaning up perchlorate at two facilities involved in high explosives research, development, and testing and is monitoring the level of perchlorate in groundwater at two other facilities. According to DOD, NASA, and DOE officials, the perchlorate detected at their facilities is largely the result of past disposal practices. Officials at these agencies told us that by complying with current federal and state waste disposal laws and regulations, they have lessened their perchlorate releases. In addition, DOD is developing perchlorate substitutes for use in weapons simulators, flares, and rockets. In the absence of a federal regulatory standard for perchlorate in drinking water, California and Massachusetts have adopted their own standards. California adopted a drinking water standard of 6 parts per billion in 2007, and Massachusetts set a drinking water standard of 2 parts per billion in 2006. The key benefits of a regulatory standard cited by state officials include protecting public health and facilitating cleanup enforcement. However, limited information exists on the actual costs of regulating perchlorate in these states. Also, at least 10 other states have established guidance levels for perchlorate in drinking water (ranging from 1 to 18 parts per billion) or in groundwater. This report contains no recommendations.