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RAMAN ANALYSIS OF FERTILIZER AND PLANT TISSUE EXTRACTS FOR PERCHLORATE CONTAMINATION
Citation:
Collette, T W. AND T. L. Williams. RAMAN ANALYSIS OF FERTILIZER AND PLANT TISSUE EXTRACTS FOR PERCHLORATE CONTAMINATION. Presented at Eastern Analytical Symposium, Atlantic City, NJ, October 1-4, 2001.
Impact/Purpose:
Elucidate and model the underlying processes (physical, chemical, enzymatic, biological, and geochemical) that describe the species-specific transformation and transport of organic contaminants and nutrients in environmental and biological systems. Develop and integrate chemical behavior parameterization models (e.g., SPARC), chemical-process models, and ecosystem-characterization models into reactive-transport models.
Description:
Recently, we and others found perchlorate at high levels (approximately 500 - 8000 mg/kg) in ~ 90% of 25+ fertilizers products (primarily lawn-and-garden type) with no known link to mined nitrate-bearing Chilean ore. This ore is used, albeit in small scale, in fertilizer production and is the only naturally-occurring material known to contain perchlorate as a trace component. Perchlorate contamination has emerged as an environmental concern since its discovery in some California water supplies in 1997 and because of its potential to affect the function of the thyroid gland. These fertilizer products were acquired over the period of November 1998 to January 1999 at 5 locations across the U.S. However, we have subsequently analyzed more than 20 similar products, which were acquired after May 1999. Some of these were the same products (although not the same lots) as those previously sampled. Most of these more-recent products do not contain detectable levels of perchlorate. Therefore, all of our results, and the results of others, suggest that the contamination of the earlier products was an episodic (if not singular) event. Nonetheless, there is an ongoing need for robust analytical methods for rapid and definitive analysis of perchlorate in complex matrices such as extracts of fertilizers and, also, plant materials, because some plants have been shown to take-up perchlorate when it is present in soil or irrigation water. We will describe the unique merits of analysis by Raman spectroscopy, without the need for prior chromatographic separation, to meet this need.