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PROVISIONAL--Information included in this presentation is preliminary and subject to revision. Preliminary Findings* of the 12-State MTBE/VOC Drinking Water Retrospective. A cooperative study by the USGS and the USEPA. Stephen Grady U.S. Geological Survey East Hartford, Conn.
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PROVISIONAL--Information included in this presentation is preliminary and subject to revision Preliminary Findings* of the 12-State MTBE/VOC Drinking Water Retrospective A cooperative study by the USGS and the USEPA Stephen Grady U.S. Geological Survey East Hartford, Conn. (860) 291-6758 sgrady@usgs.gov Michael Osinski U.S. Environmental Protection Agency Washington, D.C. (202) 260-6252 OSINSKI.MICHAEL@epamail.epa.gov * additional analysis of data will be conducted through mid-1999 with a final interpretive report plannedfor release in December 1999
Design • 12 Northeast and Mid-Atlantic States • Only community water systems (CWSs) • Representative sample of 20% of all CWSs • Stratified-random selection by source of water, size of system, and State • Water-quality data for 1993-98 obtained from State Agencies PROVISIONAL--Information included in this presentation is preliminary and subject to revision
Major Points--for 10-States* • MTBE detected in drinking water from: 7% of CWSs at concentrations > 1 mg/L 2% of CWSs at concentrations > 5 mg/L 1% of CWSs at concentrations > 20 mg/L • MTBE projected to affect: ~600 CWSs at concentrations > 1 mg/L ~180 CWSs at concentrations > 5 mg/L ~ 80 CWSs at concentrations > 20 mg/L * no MTBE data for drinking water in DE and PA PROVISIONAL--Information included in this presentation is preliminary and subject to revision
Major Points--continued • MTBE detected in 15% of CWSs in RFG/OXY* areas and 3% outside • BTEX detected in ~5% of CWSs, but not with MTBE • VOCs co-occur in ~half of samples with MTBE; mostly solvents & THMs * where oxygenate used is MTBE PROVISIONAL--Information included in this presentation is preliminary and subject to revision
PROVISIONAL--Information included in this presentation is preliminary and subject to revision
PROVISIONAL--Information included in this presentation is preliminary and subject to revision Projecting MTBE occurrence for all community water systems
MTBE detected* 5 times more often in drinking water from CWSs in RFG/OXY areas Percent of CWSs * at concentrations > 1 mg/L PROVISIONAL--Information included in this presentation is preliminary and subject to revision
PROVISIONAL--Information included in this presentation is preliminary and subject to revision
PROVISIONAL--Information included in this presentation is preliminary and subject to revision
PROVISIONAL--Information included in this presentation is preliminary and subject to revision