Pacific Southwest, Region 9: Superfund
Serving Arizona, California, Hawaii, Nevada, the Pacific Islands, and Tribal Nations
EPA #: GUD980637649
City: Near the Villages of Ordot and Chalan Pago
Congressional District: 01
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Description and History
NPL Listing History
NPL Status: Final
Proposed Date: 12/30/82
Final Date: 09/08/83
The Ordot Landfill is located near the Village of Ordot and Chalan Pago on the Island of Guam. The Ordot Landfill was established in a ravine which slopes steeply to the Lonfit River. The site has been a dumping ground since the 1940s, serving as Guam’s primary landfill for industrial and municipal waste until 2011. Final closure is expected in 2016. The 1988 ROD stated that the area covered by the landfill is 47-acres, however using both the topographic map and aerial photograph from 1994, the total acreage is calculated to be approximately 23 acres.
The site is located in a basin between two ridges in a volcanic upland region near the center of Guam at an elevation of 200 feet above mean sea level. Surface water consolidates near the northeastern boundary of the site and flows into and beneath the landfill. Runoff primarily exits south of the site into the Lonfit River, which merges with the Sigua River to form Pago River, which then drains into Pago Bay. The site is underlain with a few feet of very fine-grained volcanic sediments with a high clay content. Typically, these deposits range in color from gray to light orange in fresh exposures and gray-green to dark red in weathered exposures. The parent bedrock underlying these surficial deposits comprise tuffaceous shales and sandstones. These rock formations can range in thickness from several feet to tens of feet thick, particularly in the tuffaceous shales. Weathering is prominent to depths ranging from 10 to over 30 feet below ground surface. Both weathered and unweathered rocks appear to have extremely low permeability due to their fine-grained matrix. A major northwest-southeast trending fault is located north of the site. This fault is believed to divide the northern limestone plateau from the southern volcanic province where the site is located. Drinking water from the volcanic region is obtained from surface water upgradient of the site and groundwater from the northern limestone aquifer (the Northern Guam Water lens). Groundwater in the limestone aquifer north of the site is encountered between 120 and 330 feet bgs. No interconnection between the aquifer located in the volcanic formation beneath the site and the Northern Guam Water lens has been documented.
The Governor of Guam designated Ordot Landfill as Guam’s highest priority site for Superfund cleanup. It was placed on the National Priorities List for action under Superfund on September 8, 1983.
Contaminants and Risks
- Surface Water
- Soil and Sludges
As part of the 2002 five-year review, an evaluation of current conditions at the site was performed with respect to ecological and human health risk. The evaluation included a semi-quantitative evaluation of potential risks to ecological and human receptors based on the available data, a listing of data limitations and data gaps, and conceptual frameworks for completing a screening ecological risk assessment and human health risk assessment.
In 2007, a third five-year review was conducted, and found that the no-action remedy was expected to be protective of human health and the environment upon completion of all actions resulted by the CD (see Cleanup Results to Date).
The primary potential ecological and human health concerns of the site are:
• Uncontrolled leachate streams which discharge to the Lonfit River either directly or via tributaries.
• Subsequent pollution of the Pago River and Pago Bay.
• Methane gas fires in the landfill and subsequent generation of carbon monoxide at lower elevations.
• Exposure of aquatic and terrestrial plants, invertebrates, and wildlife to contaminated surface water, sediment, and soils.
• Bioaccumulation of contaminants in the aquatic and terrestrial food chain.
• Consumption of potentially-contaminated aquatic and terrestrial plants and wildlife by humans.
• Direct contact with contaminated surface water, sediment, and soil by humans.
• On-site hazards to workers and/or persons trespassing to scavenge. Risk evaluations were based on historical analytical data for the site.
However, the quality and comparability of the data obtained from the various studies are not consistent. The studies conducted have focused on collection of surface water and groundwater. Sediment samples were collected during a single study.
Who is Involved
This site is being addressed through Federal and Territorial actions. In September 1988, EPA issued a Record of Decision (ROD) that deferred cleanup of site threats to EPA’s Water and Waste Programs.
Entire Site: In September 1988, EPA issued a Record of Decision (ROD) that deferred cleanup of site threats to EPA’s Water Program. Cleanup actions would be handled under Clean Water Act authorities. Data collected by EPA at the time, although too limited for comprehensive conclusions, had not demonstrated any imminent and substantial endangerment to human health or the environment. As part of the preferred alternative EPA, under the Superfund Program, was to ensure the continued gathering of data to identify any adverse impacts on human health and/or the environment, especially to detect as early as possible any migration of contaminants from the landfill toward Guam’s ground water lens. The design of this program was to be based upon further hydrogeological investigations at the site. No further Superfund actions are planned unless new information warrants a response action.
The September 1988 ROD for the site prescribed not to take action under the Comprehensive Environmental Response, Compensation, and Liability Act as Amended (also known as CERCLA or Superfund), but to defer cleanup of the site to the Clean Water Act (CWA) program. The determination was based
primarily on the fact that the site was still an operating municipal landfill and that data, although too limited for comprehensive conclusions, had not demonstrated any imminent and substantial endangerment to human health or welfare or the environment.
On March 26, 1986, the United States Environmental Protection Agency (USEPA) issued an Administrative Order under the Clean Water Act, 33 USC Section 1251 et seq., that requires the Guam Department of Public Works (DPW) to cease discharge of leachate from the site to the Lonfit River.
Due to the failure of the Guam DPW to comply with the Administrative Order, the United States Department of Justice (DOJ), acting on behalf of USEPA filed a lawsuit on August 7, 2002 to force the closure of the landfill.
Cleanup Results to Date
From the time the ROD was issued in 1988 to 1993, when the first five-year review was performed, Guam DPW reduced the discharge of leachate from the site by installing a diversion ditch upgradient of the landfill that diverted water from an artesian spring away from the landfill prism. Waste cover practices were improved, and the toe of the landfill was stabilized.
The first five-year review report (USEPA, 1993) noted no apparent areas of noncompliance with regards to the no-action ROD; however, the extent of compliance achieved by the Guam DPW in response to the CWA Administrative Order was not evaluated. It was recommended that monitoring of groundwater wells be continued to confirm that contaminants from the site were not migrating towards the Northern Guam Water lens.
Little additional work was done after the 1993 five-year review report by Guam DPW to comply with the CWA Administrative Order to eliminate the discharge of leachate from the site. During a Guam EPA site inspection (Guam EPA, 1997), it was noted that daily cover was only placed along the side slopes of the waste prism and only on a few older, inactive cells. During a 1997 inspection, leachate and runoff were still observed. In November 1997, Guam DPW issued the Operations and Monitoring Plan (OMP) for the Ordot Landfill (Guam DPW, 1997) that outlined specific guidelines for waste compaction and placement of daily cover material and proposed implementing a leachate and surface water monitoring program for a period of one to two years. Guam DPW proposed not to design a leachate collection or diversion system, pending the collection of reliable and validated analytical data from the monitoring program.
On December 25, 1998, a tire pile at the site caught fire and ignited refuse on an open landfill face adjacent to it (Ecology and Environment, 1999). The refuse fire was mitigated by dumping clean fill onto the landfill face. On January 1, 1999, Guam EPA’s contractor PCR Environmental, Inc. (PCR), conducted initial air monitoring at the site for volatile organic compounds (VOCs), carbon monoxide, and oxygen. Air monitoring performed by PCR did not detect VOCs above Occupational Safety and Health Administration (OSHA) Permissible Exposure Limits (PELs). USEPA provided air surveillance and cleanup assistance at the site through the Superfund Technical Assistant and Response Team (START). Additional air monitoring data were collected by START from January 16 to 18, 1999 during the ongoing burning of the tire pile. Air was monitored for particulate matter (PM10), polynuclear aromatic hydrocarbons (PNAs), metals, carbon monoxide, oxygen, and VOCs. The preliminary data collected by START during normal burn conditions indicated no elevated risk to landfill employees or nearby residents with regard to respirable particulates, heavy metals or PAHs. The field screening carbon monoxide data indicated elevated levels at one sample location located at the landfill. It was thought by the START that those emissions were most attributable to gases being emitted from within the landfill. START assisted Mr. T. Thalhamer of the California Integrated Solid Waste Management Board (IWMB), who was brought in by EPA’s Emergency Response Team, in the assessment of emissions from the subterranean fire on the face of the landfill adjacent to the tire fire. This area had visibly subsided as the trash was combusted. There were open spaces and several vents in the surface in addition to visible stress cracks in the landfill face (Ecology and Environment, 1999) . Smoke was observed emanating from the vents. Thermal monitoring by Mr. Thalhamer indicated that temperatures in the vents exceeded those expected to normally exist in a landfill. START was unable to collect data from within the vents due to safety hazards associated with the instability of the landfill face. The data collected by START and IWMB, as well as visual observations, provided evidence of a subterranean fire at the Ordot Landfill.
Due to continued non-compliance with the CWA Order, on August 7, 2002, DOJ, acting on behalf of USEPA , filed a complaint in the United States District Court for Guam, against the Government of Guam for violating the CWA at the site (Radway, 2002). Through the complaint, the USEPA and DOJ are seeking civil penalties and actions to achieve CWA compliance and closure of the site. A primary concern for EPA is that the landfill produced leachate which discharged into the Lonfit River. The following inorganic constituents have been detected above surface water quality goals in the Lonfit River: aluminum, barium, boron, copper, cyanide, iron, lead, and manganese, mercury and silver. Inorganic constituent concentrations are also typically greater in leachate samples than in the Lonfit River, and are typically greater downstream than upstream in the Lonfit River. This trend indicates that the landfill impacted the water quality of the Lonfit River.
A second five-year review of the Ordot Landfill Superfund Site in the Territory of Guam was completed in September 2002. The five-year review documents the evaluation of whether the September 1988 no-action Record of Decision (ROD) remains protective of human health and the environment. The results of this second five-year review indicate that the no-action ROD is not functioning as intended and is not protective of human health and the environment. The site has been closed as an operating municipal landfill in accordance with applicable solid waste landfill closure requirements and guidance.
In February 2004, a Consent Decree (CD) was established between the United States and the government of Guam, establishing various deadlines for the closure of Ordot and opening a new landfill on Guam. In March 2008, the U.S. Chief Judge appointed a federal receiver ("GBB") to manage the Solid Waste Division of the Guam Department of Public Works to achieve compliance with the CD.
The most recent five-year review report completed in 2007 found that the "no action" remedy under Superfund is expected to be protective of human health and the environment upon completion of all actions required by the February 11, 2004 Consent Decree.
Potentially Responsible Parties
Potentially responsible parties (PRPs) refers to companies that are potentially responsible for generating, transporting, or disposing of the hazardous waste found at the site.
Online information about the PRPs for the site is not yet available.
Documents and Reports
Public Information Repositories
The public information repositories for the site are at the following locations:
Contact the Region 9 Superfund Office of Community Involvement.
EPA Site Manager
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Community Involvement Coordinator
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Public Information Center
After Hours (Emergency Response)