The Rota Power Plant site is located in Songsong Village on the island of Rota in the Commonwealth of the Northern Mariana Islands (CNMI).  The power plant sits approximately 100 feet from the shoreline of the Philippine Sea.  Operations at the site include the generation of power for the island of Rota, storage of new and used oil, and oil/water separation.  The Rota Power Plant site contains four primary aboveground storage tanks (ASTs) as well as day tanks and drum and transformer storage areas. 

There are two oil/water separator (OWS) systems are located at the Rota Power Plant site. One

rudimentary OWS consists of drums from which oil is manually skimmed. The system is located

inside the main Power Plant building and drains to the north of the building into a pit. A second

in-ground OWS is piped from the secondary containment areas of the ASTs and the drum storage berm located in the western portion of the property. This OWS can hold 2,500 gallons of oil and water and discharges separated water directly to a pit dug in the ground.

In addition, there are several current and former transformer storage areas where PCB-laden transformer oil may have leaked onto the soil.

FRIDAY – SUNDAY April 13 – 15, 2012:  Personnel on-site:  SERAS – 1:  SERAS geophysical contractor (Ebel) was on island and began to pick up gear which had arrived and move it into the temporary office for the site.  Much of his equipment had not arrived and he conveyed to the OSC and ERT that it had been shipped parcel post, rather than express.  All other supplies, besides one START cooler had arrived.  SERAS Ebel was onsite and ran the EM31 across the northern side of the facility to test the equipment and begin to gather data.  CUC Manglona assisted with supplies and coordination.

MONDAY April 16, 2012:  Personnel on-site: EPA – 3, SERAS – 2, START – 1, USCG – 2, ERRS – 2: OSC Rogow held a site briefing to go over tasks for the visit including:  surface and subsurface soil sampling for PCBs and TPH, groundwater sampling of monitoring wells, treatment of purge and decon water and conduct a geophysical survey.  The morning was spent organizing supplies and then the team mobed to the site to begin surface and subsurface soil sampling.  The rig that was rented from Guam was not operation, and therefore subsurface sampling began to be conducted by hand.  START also laid the grid for the surface sampling and began collecting surface soil samples.  By the end of the day, 2 shallow subsurface borings and associated samples were collected.  Sample prep and packing was conducted at the close of the day.

TUESDAY April 17, 2012:  Personnel on-site:  EPA – 3, SERAS – 2, START – 1, USCG – 2, ERRS – 2:  The first shipment of soils as shipped out (1 cooler) and surface and subsurface sample collection continued.  By the end of the day 4 shallow subsurface borings and associated samples were collected.  START and USCG continued surface sampling.  Much of the SERAS equipment had still not arrived, and so they began to work with what they had and had replacement equipment sent out.  

WEDNESDAY April 18, 2012: Personnel on-site: EPA – 3, SERAS – 2, START – 2, USCG – 2, ERRS –2:  Subsurface borings and associated samples were collected.  The rig from Guam was finally operational.  START and USCG continued surface sampling.  SERAS continued the geophysical assessment work with the equipment they had.  EPA and USCG prepared for groundwater sampling activities.

THURSDAY April 19, 2012:  Personnel on-site: EPA – 3, SERAS – 2, START – 2, USCG – 2, ERRS – 3, DEQ – 2:  Subsurface borings and associated samples were collected.  An additional ERRS subcontractor staff was brought on to assist with the operation of the rig. EPA, START, DEQ and USCG began groundwater sampling from the groundwater monitoring wells.  One of the downgradient wells (MW 5), which the well closest to the shoreline, had free product in the well, and increased concern regarding the potential for discharge to waters of the US.  SERAS continued the geophysical assessment work with the equipment they had.  The waste water treatment system for investigation derived waste water was set up.

FRIDAY April 20, 2012: Personnel on-site: EPA – 3, SERAS – 2, START – 2, USCG – 2, ERRS – 3, DEQ – 2: ERRS continued to install subsurface borings and START continued sampling of the boreholes and sampled concrete in the area of the transformers. EPA, START, DEQ and USCG completed groundwater sampling from the groundwater monitoring wells.  EPA conducted an assessment of the shoreline along the western edge of the facility.  The investigation revealed that oil was discharging into waters of the West Harbor.  Oil was observed flowing from the facility into surface waters.  EPA, START and SERAS collected soil samples along the shoreline, in the tidal zone (during low tide) in an effort to determine the extent of the oil discharge into waters. SERAS continued geophysical investigation and processing of data.

SATURDAY April 21, 2012: Personnel on-site: EPA – 3, SERAS – 2, START – 2, USCG – 2, ERRS – 3, DEQ – 2:  Surface soil sampling was completed and subsurface soil sampling continued. Concrete sampling also continued.  Water treatment of investigation derived waste water from the ground water sampling began using carbon vessels which had been brought by SERAS to treat the water.  SERAS continued geophysical investigation and processing of data.

MONDAY April 23, 2012: Personnel on-site: EPA – 2, SERAS – 2, START – 1, USCG – 2, ERRS – 2, DEQ – 2:  Subsurface soil sampling continued. Team continued treatment of accumulated investigation derived waste water.  EPA met with CUC Atalig regarding diesel product sampling and SERAS conducted product sampling of the fresh diesel being used by CUC for fingerprint analysis.  Supplies for barrier fence received.  SERAS continued geophysical investigation and processing of data.  CPA gate (along the shoreline) was locked and START has copy of the key.  Fact sheets regarding site activities were distributed by OSC Powell.

TUESDAY April 24, 2012: Personnel on-site: EPA – 2, SERAS – 2, START – 1, USCG – 2, ERRS – 2, DEQ – 2:  Subsurface sampling soil continued. Team completed treatment of accumulated investigation derived waste water and washed out drums.  Emptied spent carbon into a 55 gallon drum. START sampled spent carbon.  New carbon was placed into treatment container and tested, so that system was ready for next mobilization.  SERAS sent fingerprint samples to laboratory for analysis.  SERAS continued geophysical investigation and processing of data.

WEDNESDAY April 25, 2012: Personnel on-site: EPA – 2, SERAS – 1, START – 1, USCG – 2, ERRS – 3, DEQ – 2:  Subsurface sampling soil was completed.  Most borings were completed to planned depths, although some were more shallow than planned due to hitting refusal at depth.  After hearing allegations that the area was used to dump wastes, an additional boring was installed in the north east corner of the facility, in area of telephone pole storage.  Drilling unit was decontaminated.  CUC TMO Chargualaf was onsite and met with OSC Powell regarding work performed and areas of contamination.  SERAS began to demobe equipment and continued processing of geophysical data.

THURSDAY April 26, 2012: Personnel on-site: EPA – 2, SERAS – 1, START – 1, USCG – 2, ERRS – 3, DEQ – 2:  Team completed rinse out remaining drums.  A partial drum (1/3) of decon water remained.  One water treatment vessel was spent, but not emptied for disposal and reuse.  START conducted an inventory of supplies left on site and supplies and tools were shipped back to CNMI DEQ in Saipan.  Four drums of contaminated soil, one drum of spent carbon and a partial drum of decon water remain for disposal.  Empty drums, power auger and waste water treatment supplies were placed in CUC’s shed for storage.  ERRS installed barrier fence around area of PCB contamination.  Supplies which were borrowed from CUC were returned.  Some of the packages of equipment sent by SERAS had still not arrived by the time the site was demobed and so a list of missing items was left with CUC for further follow up.