By Rick Harston, Glasscock Underground Water Conservation District Manager
In recent months you may have heard of a contaminant named “perchlorate” being found in groundwater supplies across West Texas. Perchlorate was tested for on Oct. 9 at two sites in Glasscock County, the Garden City Water System and the Coop Gin in St. Lawrence. Perchlorate was not found in the water system, but was found at the Coop Gin at a level of 1.71 parts per billion (ppb). Within the last five years, this chemical has been found in the water supplies of more than 15 million people in the southwestern United States.
Prior to April 1997, perchlorate could not be detected at concentrations below 100 ppb. (One ppb is the equivalent of one aspirin dissolved in an Olympic-sized swimming pool.) The Environmental Protection Agency has not established a minimum drinking water standard for perchlorate. However, Texas has reduced its standard from 22 ppb as an “interim” level in l999, to four ppb in 2002.
Perchlorate originates as a contaminant in the environment from the solid salts of ammonium, potassium or sodium perchlorate. The perchlorate part of the salts is quite soluble in water. It can persist for many decades under typical groundwater and surface water conditions.
Ammonium perchlorate is manufactured for use as the oxidizer component and primary ingredient in solid propellant for rockets, missiles and fireworks. It is also used in the manufacture of matches and in analytical chemistry.
Other uses of perchlorate salts include their use in nuclear reactors and electronic tubes, as additives in lubricating oils, in tanning and finishing leather, as a fixer for fabrics and dyes, in electroplating, in aluminum refining, in rubber manufacturing, and in the production of paints and enamels. Chemical fertilizer also has been reported to be a potential source of perchlorate contamination.
Much progress has been made in developing treatment methods capable of removing perchlorate from drinking water. Reverse osmosis (RO) was tested by researchers at the Metropolitan Water District of Southern California and shown to be effective in removing perchlorate. Blair Leftwich with Trace Analysis in Lubbock recently advised that RO was an accepted method of perchlorate removal.
Testing for perchlorate can only be performed in an approved EPA lab. The cost for testing ranges in price from $80 to $250 per sample. For more information, call or come by the Glasscock Groundwater Conservation District office. Also, a copy of the EPA newsletter may be obtained at: http://www.epa.gov/safewater/ccl/perchlor/r9699fac.pdf