Full Description

Perchlorate anion (ClO4-) is a contaminant of surface and groundwaters in locationsthroughout the world, primarily as a result of military and industrial activities.Perchlorate has known thyroid activity and has been used as a pharmaceutical to treathyperthyroidism. Perchlorate, as ammonium perchlorate, is a powerful oxidant used insolid rocket fuels; hence, sources of contamination generally occur near military test sitesand chemical manufacturing plants. Perchlorate has also been detected in SouthAmerican based fertilizers due to natural deposits. Likewise, some perchlorate has beendetected in US waters where no known military or industrial activity has taken place.Often these levels are quite low and may not be detectable by traditional analyticalmethodology. The most commonly used method is EPA 314, which has a reporting limitof 4 mg/L. A novel analytical method has been developed which utilizes liquidchromatography with tandem mass spectrometry (LC/MS/MS) to accurately measuretrace (ng/L) levels of the perchlorate anion. This technique is extremely sensitive andselective with a resulting method reporting limit of 0.050 mg/L with only a 10 mLinjection volume. This technique can also detect chlorate, iodate, and bromate anionssimultaneously with similar sensitivities. Using this new technique, several surface,ground, and bottled waters were analyzed. In some waters previously thought to have noperchlorate contamination, detectable concentrations ranging from 0.050 - 0.300 mg/Lwere discovered. Several commercially available bottled waters were testing and over30% contained detectable levels of perchlorate with concentrations ranging from 0.050 -0.170 mg/L. Additionally, many of these bottled waters were found to contain bromate atlevels as great as 80 mg/L. The need for low-level analytical methods is of significantimportance considering the EPA draft reference dose for perchlorate of 1 mg/L fordrinking water. Furthermore, more sensitive analytical tools provide data necessary formore detailed fate and transport information. Using a slight variation to the drinkingwater method, this analytical method can also be used for measuring perchlorate in tissuesamples. Using this method, it was determined that perchlorate did not appreciablybioconcentrate in the tissues of fish, with resulting bioconcentration factors always lessthan one. The method described here is robust, rapid, and requires less than one mL ofsample volume, and is easily adapted for using with solid matrices such as animal tissues. Includes 26 references, tables.

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Edition: Vol. - No. Published: 11/15/2004 Number of Pages: 9File Size: 1 file , 290 KB