HR: 0830h
AN: H51C-1061    [PDF]
TI: Widespread PCE Contamination: Characterization and Source Investigation to Protect Municipal Wells
AU: * Kropf, C A
EM: ckropf@mail.co.washoe.nv.us
AF: Washoe County Department of Water Resources, 4930 Energy Way, Reno, NV 89502 United States
AU: Benedict, J
EM: remediat@mail.co.washoe.nv.us
AF: Washoe County Department of Water Resources, 4930 Energy Way, Reno, NV 89502 United States
AU: Berg, J H
EM: jberg@mail.co.washoe.nv.us
AF: Washoe County Department of Water Resources, 4930 Energy Way, Reno, NV 89502 United States
AB: Fifteen years of groundwater quality monitoring of municipal wells in Reno, Nevada have shown increasing levels of PCE (tetrachloroethylene) beyond the U.S. EPA MCL of 5 ug/L. Eleven of the 28 municipal wells have detectable levels of PCE, with five of those wells requiring wellhead treatment. The Central Truckee Meadows Remediation District (CTMRD) was created to provide wellhead treatment of PCE, and evaluate, characterize, and remediate (if possible) the PCE-contaminated groundwater. The CTMRD's first tasks of wellhead treatment, plume characterization, remediation plan development, and source zone identification has been completed. The CTMRD recently completed investigations into the presence of PCE in sanitary sewer systems and their potential as pathways for contaminant migration throughout the Reno/Sparks metropolitan area. The first phase of the sewer investigation considered the possibility that PCE resides in the sanitary sewer system and that it may be actively discharged to the sewer system as well. Results of this investigation revealed that nine sub-regions contained maximum PCE concentrations of that exceeded 100 ug/L, 20 times the U.S. EPA MCL of 5 ug/L. Eight of these nine subregions were located downgradient from active dry-cleaning facilities. One of the sampling locations had a maximum PCE concentration greater than 36,000 ug/L over a 24-hour period. The second phase of the sewer investigation explored for the sanitary sewer system to allow PCE to act as a conduit for contaminant migration. A phased approach was employed to investigate the sewer line leakage and resultant soil and groundwater impact. The investigation found that groundwater beneath most of the targeted sewer line reaches was contaminated. In particular, PCE was detected in 88% of all passive soil gas samples, 71% of all active soil gas samples, 23% of all soil samples, and 73% of all groundwater samples.
DE: 1803 Anthropogenic effects
DE: 1829 Groundwater hydrology
DE: 1831 Groundwater quality
DE: 1884 Water supply
SC: Hydrology [H]
MN: 2003 Fall Meeting