ERMUSR MISC 10-09-2007 - Laserfiche WebLink

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Sunday: Battling tainted water Page 3 of 7 The Star Tribune found that of the 20 significant pollution plumes in the metro area, 17 are in suburbs. The list is based on interviews with regulators and public health officials and a review of state cleanup and monitoring records and data. The list includes large areas of pollution -- 10 are greater than 1 square mile -- and smaller plumes with notable risks. Chemicals with abbreviations BTEX, PAHs, TCE and PCP seeped into the ground at rural dumps, industrial plants, refineries, wood-treatment operations and arms plants. Some sites had extensive cleanups, but groundwater still is contaminated. State Pollution Control Commissioner Brad Moore said cleaning up groundwater is a long-term commitment, "and we have to be vigilant to ensure the resources are there in 10, 20, 30 years from now." The plumes includes a narrow, mile-long slug of dry-cleaning chemicals beneath Farmington that is drifting toward the Vermillion River, one of the last surviving trout streams in the metro area. Recently drilled monitoring wells show that no pollution has reached the river yet. In Edina, officials discovered in 2002 that one city well contained low levels of vinyl chloride, acancer-causing chemical formed by the breakdown of other compounds. The city shut down the well, and plans to drill a new one elsewhere. The estimated replacement cost is $800,000. Groundwater-dependent cities St. Louis Park, Blaine and Bayport require special treatment of their drinking water to remove chemicals dumped long ago. Cottage Grove and St. Paul Park could be the next cities needing such water purification plants; the 3M coating compound PFBA has been detected in those cities' wells. At a U.S. Navy munitions plant in Fridley, groundwater containing a degreasing compound called TCE has been pumped out of wells on the bank of the Mississippi River for nearly two decades. Otherwise, TCE likely would enter the river --just above the Minneapolis water supply intake. Old dumping, back to haunt One of the largest groundwater problems is the 7-mile-long blob containing solvents from the former Twin Cities Army Ammunition Plant in Arden Hills that has spread to northeast Minneapolis and the Mississippi River. At its widest point, the plume is 1'/z miles across. The U.S. Army and civilian contractors dumped chemical wastes at the plant from the 1940s on. The pollution seeped into adrinking-water aquifer, and years later reached municipal wells in New Brighton, where it was discovered in 1981. For 17 years, giant carbon filters have purified the contaminated water for New Brighton's water system, removing enough solvents to fill an estimated 2955-gallon barrels, according to the Army. Ten times that amount has been extracted from groundwater and http://www.startribune.com/10237/v-print/story/1421645.html 9/21/2007