Chemist, town resident says perchlorate ‘ion-exchange’ filter economical, not experimental, used by millions; including at Cape Cod military installation


Submitted by Prof. William Moomaw, Ph.D.


The author is  a chemist with a PhD from MIT.  He  taught chemistry and conducted  research at Williams College for 26 years.  He has used ion exchange  technology in the lab and in in his home.  He is currently a professor at  Tufts University, where he is thd s senior director of Tufts Institute of the  Environment. A Williamstown resident, Moomaw served on the town’s planning board in the 1980s.  617-627-2732,


Ion exchange is recommended along with more complex biological treatment as a principle means for removing perchlorate.  In fact, this is the technology of choice for purifying vast quantities of groundwater at the Massachusetts Military Reservation on Cape Cod.


Ion exchange resins are used to soften water and remove toxic impurities to protect drinking water, remediate contaminated ground water and to reach low levels of contaminating ions for critical industrial processes. 


The process is not experimental. There are literally many millions of homes in  the United States that use this technology, which has been available  for more than 50 years, and is proven and reliable.  It is also  inexpensive ($0.30 - $0.80 per 1,000 gals.), and can be installed in a very short period of time.  Systems are modular and come in sizes for a single water faucet up to systems that can treat thousands of gallons per day.

High levels of perchlorate are known to cause thyroid damage.  There is no set standard for perchlorate, but a recommended level of no more than 1.ppb has been tentatively set by US EPA while a standard is being  set.  This is a very conservative level.

There are two different ion exchange systems.  Each is capable of removing perchlorate down to the 1 ppm pr better, and one is supposed to reach the limit of detection level of 0.35 parts per billion (ppb) as defined by US EPA.

One manufacturer, Rohm and Haas has developed a special ion exchange resin especially for perchlorate that is claimed to be the most efficient available. (1-800 RH Amber)


The Rohm and Haas resin is tuned to pick up perchlorate. A company official contacted by the author on Nov. 23, 2004, said the company would want to have a chemical analysis of the water from the well where it is applied. But except in very unsusual situations, the resin typically brings perchlorate down to an undetectable level which is 0.35 ppb – or roughly one third of the 1.0 ppb standard that the EPA is talking about as a presumed safe standard.

The company official said the minimum amount of resin sold comes in a 7-cubic-foot drum, which costs $588 per cubic foot, or $4,116 plus freight from Pennsylvania.The company said one cubic foot will treat 2 gallons per minute of drinking water. In terms of the resins, this means approximately a $2,500 a year cost to change resins. Money is available from the state agency which oversees school construction as part of renovation initiatives and the money is also available on an emergency basic. It is our responsibility to the children and staff at Mount Greylock to check out these opportunities and possibilities in order to resolve this problem as quickly as possible.


This resin technology is available to consumers generally. For example, on my tap at our second home in the Boston area, I have a water-purifying unit, widely available in the Boston area, which removes a wide range of potential contaminates, including perchlorates. It costs me $200 for the whole system and less than $100 a year to replace the resin filter.



Further  information may be obtained from Kris Kurley of the Impact Area  Groundwater Study Program 508-968-5626, Ellie Grillo, Mass. Dept. of  Environemntal Protection; or Jim Murphy, USEPA, 617-918-1028.  There is also a website A summary of 65 perchlorate treatment studies for groundwater is available online at