North Railroad Avenue Plume Superfund Site Update September 11, 2018

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1 North Railroad Avenue Plume Superfund Site Update September 11, 2018 Angelo Ortelli Project Manager New Mexico Environment Department Mark Purcell Remedial Project Manager U. S. EPA Region 6 (214) purcell.mark@epa.gov

2 Bond Well Norge Town Cleaners Shallow Plume Site Description Site discovered in 1989, two Espanola municipal wells (Jemez and Bond wells) were impacted Deep Plum e Jemez Well Source Norge Town Dry Cleaner at 113 North Railroad Ave. Site consists of groundwater contaminated with PCE, TCE, DCE covering approx. 60 acres Santa Clara Pueblo Tribal Lands Soil contamination restricted to 40 x 40 sq. ft. area behind dry cleaners Shallow aquifer ground water plume (0 to 30 ft) extends approx. ¾ -mile south Deep aquifer ground water plume to 260 ft below ground surface Shallow and Deep Contaminated Ground Water Plume Boundaries

3 Site Description Highest concentrations in 2006 prior to remediation start-up: Contaminant shallow (<30 ft) deep (200 ft) Clean-up Goal (EPA MCL) PCE , µg/l TCE µg/l DCE (cis + trans) Not Detected 70 and 100 µg/l VC Not Detected Not Detected 1.0 µg/l No contaminants have been detected in current City Supply wells. Closest supply well (Rio Grande well) is approx. one mile northwest of ground water plume (Well currently used for irrigation only) Based on historical data the plume appears to be stable prior to active remediation efforts 1999 Site added to National Priority List (NPL) provides federal funding source Sept Record of Decision signed - Establishes clean-up goals and methods (i.e. bioremediation)

4 SOURCE & HOT-SPOT AREAS BIOCURTAIN Treatment System Areas Source Area 10 injection wells & 4 extraction wells Hotspot Area 19 injection wells & 14 extraction wells Biocurtain 9 injection wells & 10 extraction wells Red - Shallow Yellow Intermediate Blue - Deep Deep Zone 2 injection wells & 12 monitoring wells 1-MILE

5 NRAP Remediation Schedule $5.2 million construction and oversight budget, ~$500K annual operating budget to run system - 90% Federal funding and 10% State match - 100% State funded after 10 years of remediation (2019) August 2005: Began bioremediation system construction December 2005: Completed drilling of 90 bioremediation wells (injection and extraction) January 2008: Completed bioremediation pilot testing & began conversion/modification for full scale operations

6 NRAP Remediation Schedule (Cont d) : Bioremediation system operations - Initial amendment (vegetable oil) injections to all four treatment areas, April & October Amendment doses added to hotspot & biocurtain areas, April & August Amendment injections to deep zone, August Amendment dose added to source area, April Targeted amendment doses added to source area using direct-push & Sonic drilling/injection methods, April & September 2017

7 NRAP Remediation Schedule (Cont d) : NMED conducts groundwater monitoring - Semi-annual sampling, Annual sampling, July 2010: First Five-Year Review (EPA Region 6) February 2015: Optimization review of Long-Term Response Action (EPA Region 6) July 2015: Second Five-Year Review (EPA Region 6)

8 PCE Concentrations PCE MCL 5.0 µg/l Source above Hunter: >40,000 µg/l Hunter to Onate: µg/l Stanley Griego Bridge: < 10 µg/l Source above Hunter: < µg/l Hunter to Onate: < 5 µg/l Stanley Griego Bridge: < 10 µg/l

9 TCE Concentrations TCE MCL 5.0 µg/l Source above Hunter: 830 µg/l Hunter to Onate: µg/l Calle Chavez: 120 µg/l Stanley Griego Bridge: < 30 µg/l Source above Hunter: < 1.0 µg/l Hunter to Onate: < 2.0 µg/l Calle Chavez: 68 µg/l Stanley Griego Bridge: < 14 µg/l

10 Shallow Zone Results to Date Source Area - PCE reduced from >40,000 to <400 µg/l - Vinyl chloride (VC) reduced from >15,000 to <500 µg/l, but still decreasing Hotspot & Downgradient Areas - all contaminants below EPA MCLs except VC - PCE &TCE still detected in one biocurtain well at 4 µg/l and 47 µg/l, respectively

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12 Deep Zone 180 to 265 ft bgs 90 % contaminant decrease observed in individual injection wells Limited degradation observed in nearby monitoring wells Additional investigation is needed to address data gaps

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14 Objectives of Upcoming Investigation Refine interpretation of groundwater flow direction Further delineate contamination in the intermediate & deep hydrostatigraphic units Evaluate natural attenuation Investigate additional potential source

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18 Questions? Angelo Ortelli Project Manager New Mexico Environment Department Mark Purcell Remedial Project Manager U. S. EPA Region 6 (214) purcell.mark@epa.gov