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RELIABILITY STUDY OF THE U.S. EPA'S METHODS 101A - DETERMINATION OF PARTICULATE AND GASEOUS MERCURY EMISSIONS
Citation:
Wilshire, F., J. Knoll, T. Ward, AND M. Midgett. RELIABILITY STUDY OF THE U.S. EPA'S METHODS 101A - DETERMINATION OF PARTICULATE AND GASEOUS MERCURY EMISSIONS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/D-91/219 (NTIS PB91233361).
Description:
EPA Method 101A applies to the determination of particulate and gaseous mercury missions from sewage sludge incinerators and other sources. oncern has been expressed hat ammonia or hydrogen chloride (HCl) when present in the emissions, interferes in the analytical processes and produces a high positive bias in the mercury results. ecause HCl and ammonia are present in the effluents from municipal waste incinerators where chlorinated plastics are combusted, the present laboratory study was conducted to investigate these concerns. tandard EPA Method 101A sampling train was employed in the study. he source of Hg vapor consisted of two certified Hg permeation tubes. he mercury vapor was directed into a stream of filtered laboratory air and sampled at rates varying between 15 and 30 L/min. pproximately 1 m of gas was collected in each sample run. ide stream of ammonia vapor was added to the gas sampled in half of the runs to determine the effects of that substance. ercury recoveries with and without added ammonia were 97.3 + 3.4 and 96.8 + 1.3%, respectively. pplication of the Aspin-Welch test for the difference between two sample means showed that this difference was not statistically significant. he effect of added HCl was also studied. ercury and HCl were added to samples of the acid permanganate reagent and subjected to the Method 101A analytical procedure. ercury recoveries were 100.0 + 5.2, 101.3 + 8.5, and 98.0 + 5.4% for 0, 1, and 7 g of added HCl, respectively, indicating no effect of HCl on the analysis, a stream of filtered laboratory air, which as sampled at rates which varied between 15 and 30 L/min. pproximately 1 m3 of gas was collected by the sampling train. ide stream of ammonia vapor was added to the gas sampled in half of the runs to determine the effects of that substance. pon completion of the runs, the samples were recovered and analyzed by the Method 101A procedures, which included measurement using a Perkin-Elmer Model 403 atomic absorption spectrophotometer for the cold vapor analysis. ercury recoveries with and without added ammonia were 97.3 + 3.4 and 96.8 + 1.3%, respectively. pplication of the Aspin-Welch test for the difference between two sample means showed that this difference was not statistically significant. The effect of added HCl was also studied. ercury and HCl were added to samples of the acid permanganate reagent and subjected to the Method 101A recovery and analytical procedure. he samples were analyzed weekly for 37 days. ercury recoveries were 100.0 + 5.2, 101.3 + 8.5, and 98.0 + 5.4% for 0, 1, and 7.5 9 g of added HCl, respectively, indicating no effect of HCl on the analysis. hese results are actually not surprising, since HCl is employed in the Method 101A cleanup procedure in far greater amounts than might be collected in stack sampling. Cl does produce chlorine when added to the acid permanganate solution, but the chlorine is subsequently reduced when reacted with hydroxyl amine and stannous chloride, reagents employed in the Method 101A procedure. urther, when a mercury blank is analyzed, there is no evidence of a chlorine signal in the atomic absorption analysis.