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Dennis Welsch <br />Page 4 of 4 <br />May 17, 2002 <br />single gram of inercury emitted by the facility entered the reservoir through the reservoir's <br />narrow breathing tube (which is e�tremely urllikely), the concentration of inercury in the drinking <br />water would be 172 nanograms per liter (ng/1), which would remain less than 2% of the EPA's <br />Federal Drinking Water Standard of 2,000 ng/l. <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 inercury 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 NIl'CA, mercury concentrations eventually reach equilibrium <br />directly proportional to the mercury deposition. According to the NIDH 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/1), 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 />7ackson states that recent NIPCA efforts to reduce large-scale mercury emissions (such as coal- <br />burning facilities) ha�e been very successful, so that net effect on the current mercury deposition <br />will be minimal. <br />Summary <br />Based upon DPRA's review of the e�sting emission and health-effect information regarding the <br />proposed crematory facility, it appears that a clear presentation of the results of the EPA Study <br />and the NIl'CA air dispersion modeling and to�city assessment may add clarity to the issues <br />raised during the City Council meeting. <br />If you have any questions regarding this letter or any of the information discussed, please ca11 me <br />at (651) 227-6500, ext. 3158. <br />Sincerely, <br />� <br />Donovan Hannu, P.E. <br />Civil Engineer <br />cc: Anne Jackson - NIPCA <br />DPRA File 578 1.0004 <br />