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Response to Comment on “Off-Site Forensic Determination of Airborne Elemental Emissions by Multi-Media Analysis: A Case Study at Two Secondary Lead Smelters SIR: Amter and Eckel make an important point that the ratios we found were “fingerprints” for the particular secondary smelters we studied and not necessarily characteristic for the entire industry. The facilities we analyzed had extensive air pollution control equipment around the furnace buildings while the older facilities in Texas most likely did not. The ratios we found represent the emissions from unconfined scrap heaps rather than furnaces, which would produce difference ratios. So operational differences are certainly a possible explanation. However, the differences in ratios may also be influenced by analytical differences. Amter and Eckel most likely used U.S. EPA SW 846 Method 3050A (or a similar procedure), which uses nitric acid exclusively or as the dominant acid. Such procedures solubilize antimony very poorly (1-4) as compared to Method 3050B (3055) where hydrochloric acid is dominant. Also, the mean arsenic and antimony values (6 and 2 mg/kg, respectively) for the second soil sample group are close to background values (at least for California soils), which can skew the results. Further, given the very low mean concentrations of antimony and arsenic in the second sample group, it seems likely that graphite furnace atomic absorbence spectroscopy (GFAAS) was used to analyze the acid digestates of the soils. All analytical procedures are subject to greater uncertainty at low concentrations (5, 6), and GFAAS is especially problematic when analyzing acid digestions of soils (7).
S0013-936X(95)01013-3 CCC: $12.00
1996 American Chemical Society
Literature Cited (1) Kimbrough, D. E.; Wakakuwa, J. R. A Study of the Linear Ranges of Several Acid Digestion Procedures. Environ. Sci. Technol. 1992, 26, 173-178. (2) Kimbrough, D. E.; Wakakuwa, J. R. Report of an Interlaboratory Study of an Interlaboratory Study Comparing EPA SW 846 Method 3050 and an Alternative Method from the California Department of Health Service. In Waste Testing & Quality Assurance: Third Volume; ASTM STP 1075; Tatsch, C. E., Ed.; American Society for Testing and Materials: Philadelphia, 1991. (3) Kimbrough, D. E.; Wakakuwa, J. R. Acid Digestion for Sediments, Sludges, Soils, and Solid Wastes. A Proposed Alternative to EPA SW 846 Method 3050. Environ. Sci. Technol. 1989, 23, 898-900. (4) Kimbrough, D. E.; Suffet, I. H. A Method for Multi-Element, Multi-Media Analysis for the Determination of Airborne Elemental Emissions. Analyst, in press. (5) Kimbrough, D. E.; Wakakuwa, J. R. The Quality Control LimitsAn Alternative to Detection Limits. Environ. Sci. Technol. 1994, 28 (2), 338-345. (6) Kimbrough, D. E.; Wakakuwa, J. R. A Study of Method Detection Limits in Solid Waste Analysis. Environ. Sci. Technol. 1993, 27 (13), 2692-2699. (7) Kimbrough, D. E.; Wakakuwa, J. An Inter-Laboratory Comparison of Instruments Used for the Analysis of Elements in Acid Digestates of Solids. Analyst 1994, 119, 383-388.
David Eugene Kimbrough* Castaic Lake Water Agency 27234 Bouquet Canyon Road Santa Clarita, California 91350
I. H. Suffet School of Public Health Environmental Science & Engineering Program University of California, Los Angles Los Angeles, California 90095-1772 ES951013T
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