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SURVEY OF FERTILIZERS AND RELATED MATERIALS FOR PERCHLORATE
Urbansky*, E T., T W. Collette, W. P. Robarge, W. L. Hall, J. M. Skillen, AND P. Kane. SURVEY OF FERTILIZERS AND RELATED MATERIALS FOR PERCHLORATE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-01/047, 2001.
The most comprehensive survey of fertilizers and other raw materials for perchlorate to date has been conducted to determine whether these could be significant contributors to environmental perchlorate contamination. Although the data span a large range of commercial products, they represent only a snapshot of currently used products, at least in a temporal sense. Field samples of 48 different products from manufacturers of major commodity chemicals were collected from representative sites around the nation. These covered major sources of macronutrients, some sources of micronutrients, and several sources of fillers/additives. Whenever possible, field samples were collected under supervision of state chemists or agriculture department staff. The field samples were riffled and divided; portions of each material were sent to several laboratories for analysis. Perchlorate was dissolved by leaching the material with deionized water with shaking. Subsequently, the aqueous leachates were subjected to ion chromatography using Dionex IonPac AG16 and AS16 columns. All materials were tested by at least four independent laboratories. Laboratories were required to demonstrate satisfactory recovery of fortifications and performance on 7 quality control samples; agreement on duplicate portions (not identified to the labs) of four materials was also required. Each laboratory had previously been subjected to a performance evaluation using test samples. Except for those products derived from natural Chilean caliche (a natural perchlorate source), the specific natures of the manufacturing processes suggest that perchlorate should not be present in most fertilizers. Chilean nitrate salts constitute about 0.14% of US fertilizer application. Perchlorate was positively detected only in those materials known to be derived from caliche. Limited discussion is included on the implications for agriculture and horticulture as well as factors that complicate investigations or data analysis and interpretation.