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EPA Orders Marlborough to Cut Copper Discharges to Assabet River

Release Date: 08/08/2001
Contact Information: Mark Merchant, EPA Press Office (617) 918-1013

BOSTON – The U.S. Environmental Protection Agency today issued a consent order to the city of Marlborough requiring it to reduce the amount of copper one of its two wastewater treatment plants discharges into the Assabet River.

The city's West Plant discharges an average of 2.1 million gallons of wastewater a day into the Assabet. Under a National Pollutant Discharge Elimination System (or NPDES) permit EPA issued in 1993 for the city to operate the plant, a maximum of 36 micrograms per liter (ug/l) of copper a day may be discharged into the river. This permit sets the average monthly copper discharge into the Assabet at no more than 23.5 ug/l.

Marlborough's NPDES permit was re-issued in 2000 and set the maximum daily copper discharge at 18 ug/l and the monthly average at 13 ug/l, however, the requirements for copper discharges in this permit have not yet gone into effect. The city has been unable to consistently meet EPA's copper discharge requirements in the 1993 permit, and neither EPA nor the city believe Marlborough will be able to consistently meet the 2000 permit requirements once they go into effect.

But the EPA order issued today is a starting point towards resolving that problem. The order requires the city to look for ways to reduce the amount of copper being discharged into the Assabet from the West Plant and to develop an action plan to further reduce the level of copper discharges.

The copper limits are based on state water quality aquatic life criteria for protection against acute and chronic toxicity. The town's discharges currently exceed the levels necessary to protect against toxic effects on the aquatic environment.

"EPA has been working with Marlborough officials to tackle the problems of high levels of copper in wastewater discharges and will continue do so," said Robert Varney, regional administrator of EPA's New England office. "Reducing the amount of copper sent into the Assabet River will have far reaching effects such as enhancing the fishing and swimming opportunities in the river,"

The Assabet River is a Class B Waterway, which means it must be clean enough to support fishing and swimming and other recreational activities.

NPDES controls water pollution by regulating point sources such as wastewater treatment plants that discharge pollutants into waters of the United States. Since its introduction in 1972, the NPDES permit program is responsible for significant improvements to our nation's water quality. For more information on the NPDES program, visit EPA's Web site: