Edoni Formerly Used Defense Site
The Edoni Formerly Used Defense Site is approximately 7.43 acres with a 1.4 acre burrow pit which the U.S. Military used as a waste disposal dump site. At the site, military vehicle parts, empty cylinder gas tanks and other debris were dumped into the pit. The pit is also contaminated with PCB tainted soil and lead contaminated soil. The site is located in a densely vegetated area surrounded by residential homes. The Marianas Public Lands Authority has proposed to develop this parcel of public land for residential homestead. However, the proposed project has been put on hold due to the current condition of the site.
The Edoni Site was reportedly mined for coral aggregate for the purpose to maintain and repair Saipan’s military airfields following the capture of the island of Saipan from the Japanese forces in July 1944. With the mining of coral aggregate, as a result, there is a burrow pit which the U.S. military purportedly used as an open dump following the ending of mining operations at the burrow pit.
Edoni Site remediation activities occurred from January 16 to March 20, 2012 and from April 16 to May 18, 2012, after obtaining right of entry from the CNMI Department of Public Lands and William Ada, the latter and private landowner whose property was used to access the former open dump. During these periods, PCB-impacted and lead-contaminated soils were excavated using a tracked excavator and rubber tired backhoe from a land area spanning approximately 1.4 acres to a depth of about 12 inches (0.30 meter) to as much as 6 feet (1.83 meters) in some areas as dictated by underlying limestone formation contours. Soul excavation within the former open dump was guided by incremental soil sampling within four decision units and attendant laboratory analysis as well as real-time metals measurements using an X-ray fluorescence (XRF) spectrum analyzer to achieve in situ concentrations below 1.1 mg/kg as total PCBs warranted removal of the organic soil matrix that presumably was imported from off-site sources either with the debris disposed at the site or periodically deposited as cover material after the debris was discarded in the former borrow pit. Achieving PCS and lead concentrations below the ESL of 1.1 mg/kg and 200 mg/kg, respectively, for shallow soil (less than 3 meters) and unrestricted land use therefore meant having to remove that soil horizon to the underlying limestone formation.
Because TCLP concentrations did not exceed regulatory thresholds, a total of 161 truckloads of lead-contaminated soil were transported to Marpi Solid Waste Facility as non-hazardous waste from February 2012 to May 2012. Assuming the equivalent of 1.25 tons per cubic yard, approximately 1,877 cubic yards (2,346 tons) of lead-contaminated soil were excavated from the site and transported to the on-island landfill.
An assortment of metallic debris was extracted by hand by on-site personnel to the extent possible as soil excavation ensued. The debris was periodically loaded onto dump or flatbed trucks for off-site transport and recycling. Eighteen truckloads of unearthed debris were transported to one on-island metal recycler, i.e., Saipan Triple Star Recycling.
Several munitions and explosives of concern (MEC) were unearthed as PCB-impacted and lead-contaminated soil excavation ensued. These items were identified by the on-site MEC Monitor as they were encountered. Due to personnel and public safety concerns, arrangements were made with the CNMI Explosives Response Team to remove several MEC items from the site and to transport them to the CNMI government's secure MEC storage site for eventual destruction. The items included an unfused U.S. 81 mm mortar, an unfused and incomplete U.S. 75 mm projectile, and two Japanese 50 mm Type 89 mortars. Expended munitions debris determined by the on-site MEC Monitor not to present a hazard to project personnel or the public included U.S. 37 mm, 75 mm, and 105 mm cartridges, a U.S. cluster bomb fin assembly, and Japanese 13 mm, 14.5 mm, 20 mm, 25 mm, 70 mm, and 105 mm cartridges.
Soil adhering to machinery and mechanized equipment utilized during site remediation was scraped off equipment components and undercarriages while still at the site and before being transported back to its respective operator base yards.
As requested by DEQ, an approximately 6-foot-tall berm was formed across the span of the cleared pathway to and from the Edoni Site former borrow put and open dump following the completion of remediation activities to prevent vehicular access into the site. An earthen ramp off Ibid Drive onto the Ada property was retained as requested by the landowner, and a silt fence between the private property and the road was extended across the ramp to prevent surface runoff. Restoration of the former borrow put and open dump was not performed and deemed unnecessary by the CNMI Department of Public Lands because of the site's master-planned intended use as a surface runoff ponding basin.
The following RECs were found: Materials onsite include two deteriorating compressed gas cylinders, glass bottles, metal sheeting, batteries, mechanical parts, and miscellaneous plates, as described in the U.S. Army Corps of Engineers Remedial Investigation (RI) report, likely comprised of porcelain and lead. Additional Phase II investigation is recommended based on the RECs identified. A Phase I ESA was completed in March 2011.
Category: Brownfields
Coordinates: N-15.20148; E-145.75636
Island: Saipan
Village: Capital Hill
Response Status: Approved for Brownfields Phase I ESA in 2009; Phase II was completed in May 2012.
Land Use Restrictions: Residential
Institutional Controls: Fence around the site boundary
Responsible Party: Unknown
Enforcement Authority: Division of Environmental Quality (DEQ); U.S. Environmental Protection Agency (EPA)
Project Lead: Division of Environmental Quality (DEQ)
Property Status: Department of Public Lands
Coordinates: N-15.20148; E-145.75636
Island: Saipan
Village: Capital Hill
Response Status: Approved for Brownfields Phase I ESA in 2009; Phase II was completed in May 2012.
Land Use Restrictions: Residential
Institutional Controls: Fence around the site boundary
Responsible Party: Unknown
Enforcement Authority: Division of Environmental Quality (DEQ); U.S. Environmental Protection Agency (EPA)
Project Lead: Division of Environmental Quality (DEQ)
Property Status: Department of Public Lands