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<br />Dennis Welsch <br />Page 4 of 4 <br />May 17,2002 <br /> <br />single gram of mercury emitted by the facility entered the reservoir through the reservoir's <br />narrow breathing tube (which is extremely unlikely), the concentration of mercury in the drinking <br />water would be 172 nanograms per liter (ng/l), which would remain less than 2% of the EPA's <br />Federal Drinking WaterStandard of 2,000 ng/l. <br /> <br />In a letter from Ms. Jackson dated August 3, 2001, the MPCA also evaluated the mercury impact <br />on McCarron Lake. The concentration of mercury in the air that will reach McCarron Lake, <br />based upon the SCREEN3 air dispersion modeling, was used to calculate mercury deposition. <br />Mercury deposition in McCarron Lake will increase from 23% to 300%, depending on the <br />number of cremations performed. This calculation does consider the long-term accumulation of <br />mercury, because according to the MPCA, mercury concentrations eventually reach equilibrium <br />directly proportional to the mercury deposition. According to the MDH Fish Advisories List, the <br />original mercury concentration in this lake (without a crematory facility) is less than 0.16 ppm <br />(equivalent to 160 ng/l), so even with the worst-case 300% increase in mercury deposition, the <br />mercury concentration will be within the range of unlimited fish consumption. In addition, Ms. <br />Jackson states that recent MPCA efforts to reduce large-scale mercury emissions (such as coal- <br />burning facilities) have been very successful, so that net effect on the current mercury deposition <br />will be minimal. <br /> <br />Summary <br /> <br />Based upon DPRA's review of the existing emission and health-effect information regarding the <br />proposed crematory facility, it appears that a clear presentation of the results of the EP A Study <br />and the MPCA air dispersion modeling and toxicity assessment may add clarity to the issues <br />raised during the City Council meeting. <br /> <br />If you have any questions regarding this letter or any of the information discussed, please call me <br />at (651) 227-6500, ext. 3158. <br /> <br />Sincerely, <br /> <br />~ fJ'^-(f\f'v <br /> <br /> <br />Donovan Hannu, P.E. <br />Civil Engineer <br /> <br />cc: Anne Jackson - MPCA <br />DPRA File 5781.0004 <br />