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DATE: August 10,200 I SF.00006.05 (4/86) STATE OF MINNESOTA Office Memorandum cC'. c,~ Bu.:h weJ5.ck rJah~ I~.IJM, DE~ARTMENT: POLLUTION CONTROL AGENCY ~ ' TO: Thomas Paschke City of Roseville FROM: Anne Jackson, P.E. Policy and Planning Division Minnesota Pollution Control Agency PHONE: (651 )296-7949 SUBJECT: Further Infonnation on the Impacts of Cremation I am providing additional infonnation as a followup to my August 3, 2001 submittal to the City of Roseville. Impacts on Water Ouality The chemical fonn of mercury matters. The mercury that fish accumulate in their tissues, methylmercury, is readily absorbed by the human digestive system. But our digestive system does not readily absorb inorganic mercury in drinking water, that is, the mercury found in crematory emissions and air deposition. Methylmercury is fonned when bacteria in lakes and wetlands change the chemical fonn of mercury that deposits from the air onto lakes and wetlands. Because it is absorbed, methylmercury is much more toxic than the inorganic fonns of mercury. Minnesota has set the allowable level of total mercury in surface waters (lakes) at 6.9 nanograms per liter (ng/L, or 0.0000000069 grams per liter), in order to protect fish from the buildup of methylmercury. As a comparison, the federal drinking water standard for mercury is 2000 ng/L (or, 0.000002000 grams per liter) which is set to be protective of humans. (Lungs do absorb inorganic mercury quite efficiently. This route of exposure was assessed in the August 3 memorandum.) Citizens in Roseville expressed their concern that the quality of the drinking water in the St. Paul Regional Water Service would be negatively impacted by the presence of mercury in the air. Air is drawn into the reservoir during its operation as water levels fall; air leaves the reservoir as the water level rises. . Rather than attempt to deternline the amount of air drawn into the reservoir (and released) and detennine whether or not the air is held long enough for the mercury to be transferred from the air to the water, I have constructed a highly conservative estimate of impacts on water quality by assuming ALL mercury released from the crematory during the course of a year is directed entirely to the reservoir. If 2190 cremations were perfonned at Roselawn per year, based on EP A emission factors 1924 grams of mercury would be released. RECYCLED PAPER WITH A MINIMUM OF 10% PQSTCONSUMER WASTE t!) .0\ C{ .\. ~