Fluoride Action Network

Want Less Arsenic in Your Fluorosilicic Acid?

Source: Fluoride Action Network | August 21st, 2001

According to Thomas Reeves, the fluoridation engineer at the CDC, some communities with elevated levels of arsenic in their water “may wish to buy acid with a low amount of arsenic impurity.” The acid Reeves is referring to is fluorosilicic acid, the nation’s most commonly used fluoridation chemical, which is often contaminated with low levels of arsenic and other impurities.

According to the National Sanitation Foundation, fluorosilicic acid has been found to contribute approximately 0.43 parts per billion arsenic to finished drinking water when the contaminant is present in the acid. The NSF further notes that, in some cases, the level of arsenic contributed from the acid can range as high as 1.66 ppb.

For communities who would like to receive less arsenic in their fluorosilicic acid, Reeves notes that they should “write into their specifications on their purchase orders for the chemicals what arsenic level they will allow.”

To learn more about the source of the fluorosilicic acid used for fluoridation, and why it’s contaminated with arsenic, visit http://www.fluoridealert.org/phosphate/overview.htm


Reeves’ full statement, which was released July 2001, is as follows:

From: Central Massachusetts Oral Health Initiative

EPA’s new Maximum Contaminant Level (MCL) of 10 ppb [parts per billion] of arsenic, will have no real effect on fluoridation in this country. First, both sodium fluoride and sodium fluorosilicate have virtually no arsenic impurities and will not be a problem. Fluorosilicic acid can have trace amounts of arsenic. In some cases, it may add up to 0.5 ppb in the finished drinking water of a water system, which will be part of the MCL of 10 ppb. This would not be a problem. In the U.S. some small water systems, especially in the northeast part of the country, have ground water [wells] that may have a natural level of arsenic approaching 10 ppb [or may exceed 10 ppb]. They may wish to buy acid with a low amount of the arsenic impurity. What is required is to write into their specifications on their purchase orders for the chemicals what arsenic level they [the water system] will allow. Since much of the acid that is produced will have very low arsenic, that is what the system should get. They might have to pay more money for the fluorosilicic acid, but remember it will be a small system that uses small amounts of acid, thus generally, a small increase in cost. In an extreme case, probably less that 10 total [small] systems in the U.S., they can switch to another chemical, like sodium fluoride with a saturator.

The Maximum Allowable Level (MAL) issue that those opposed to water fluoridation constantly quote needs clarification. The MAL is not an “enforceable regulation”. The only enforceable [by the state or the U.S. EPA] requirements are the MCLs. When a community or water system purchases chemicals for water treatment, they can write in their purchase orders that the chemicals must meet the American Water Works Association, AWWA, and/ or National Sanitation Foundation, NSF, standards. [CDC recommends all systems use these standards.] When they do this, one of the requirements of the NSF Standard 60 is that the MAL for a regulated chemical, like arsenic, not be exceeded. The MAL for arsenic is 1/10th of the MCL or 1.0 ppb. The manufacturer will supply the chemical, fluorosilicic acid, with tests that show they have met this standard. If the standard is not met, then the city or water system should reject the acid and not pay for it.

Thomas G. Reeves, P.E., is a fluoridation engineer who can be reached for more information at the CDC.