Resources: Information about Perchlorate

Perchlorate contamination is an issue for several TOSC communities. Below are answer to some frequent questions about Perchlorate and links to references with additional information.

What is perchlorate?

It is both a naturally occurring and man-made chemical. Most perchlorate (as ammonium perchlorate) manufactured in the United States was used in rocket fuel, missiles, and fireworks. Perchlorate salts are also used in air bags, lubricating oils, electroplating, rubber manufacture, etc. Chemical fertilizer has also been reported as a potential source of perchlorate, but EPA, based on new investigations, does not consider it to be an issue for agricultural applications.

What are the health effects of perchlorate?

Perchlorate, when ingested, can limit the uptake of iodide by the thyroid gland. Continual disruption of the thyroid gland can impede the ability of the gland to produce thyroid hormones that regulate metabolism and growth. Infants and pregnant women are particularly susceptible to the health effects that disruption of thyroid functions can cause.

What does the thyroid do?

In children, the thyroid plays a major role in proper development and metabolism. In adults, the thyroid regulates metabolism. In expectant mothers, impairment of the thyroid can impact the fetus and cause behavioral changes, delayed development, and decreased learning capacity.

How is perchlorate regulated?

No federal drinking water standard—also called a maximum contaminant level (MCL)—exists for perchlorate. However, many states are exploring setting their own standards for perchlorate levels.

In California, for example, state statutes require the Department of Health Services (DHS) to adopt a maximum contaminant level (MCL) for perchlorate in drinking water by January 1, 2004. Until an MCL is in place, DHS uses a 4 micrograms per liter advisory action level to protect consumers from perchlorate’s adverse health effects. The MCL must be as close as technically and economically feasible to its Public Health Goal (PHG). A PHG is a contaminant’s concentration in drinking water that does not pose any significant health risk, derived from a human health risk assessment. California’s Office of Environmental Health and Hazard Assessment (OEHHA) established a PHG of 2 to 6 micrograms per liter for perchlorate in a 2002 draft report.

Where can I find more information about perchlorate?

Summary information about perchlorate from the US Environmental Protection Agency -- General information about perchlorate including a summary of actions the USEPA is taking.

Technical Reports from the US Environmental Protection Agency. -- These are written for scientists and describe current understanding of health effects and analyses of health risks.

Perchlorate in California Drinking Water: Status of Regulations and Monitoring Results -- This is an update, written February 2003 about California's current actions about perchlorate contamination.

Perchlorate in California Drinking Water – DRAFT Public Health Goal (PHG) (This file is pdf document.) -- In California, a PHG is the level of a contaminant which the state determines does not pose a significant health risk. This is California's draft document for perchlorate.