3.1 NAVMAG 10 - Small Arms (Pistol) Range
Rationale for use of composite sampling.
Site 10 was the only site where composite sampling was used. It is also the site for which the most simple analysis was conducted on soil samples. At Site 10 soil sample analysis was conducted for lead only. Despite this relatively inexpensive test composite sampling was used at Site 10 and not at the other 43 sites where pollutant scans were conducted for over 270 chemicals.
Site cleared in 1990 and never subsequently used.
The pistol range at Site 10 was rebuilt in 1990. Before use it was damaged by the Mt. Pinatubo eruption. The design of the pistol range prior to 1990 should therefore have been used to determine sample locations.
During reconstruction the potential lead contamination at the site may have been relocated to other areas in the Freeport Zone. No information on the scope of the 1990 range reconstruction project was provided during the EQS.
Target areas were not sampled.
The soil sample locations are located between the firing points and the target area. These sample locations do not appear to correspond to any target lines. Spent bullets are likely found in close proximity to the target areas and not in the site areas that were sampled.
Site maps indicate additional range areas located in this area.
Site figures show, in addition to two pistol ranges, a number of rifle ranges. The sampling that was conducted targeted only one of the pistol ranges. No explanation for excluding these other ranges areas from sampling was provided in the EQS.
Historical information and new samples need to be collected for this site.
The evaluation of this property should be re-performed. The existing historical information and sampling results are not adequate to rule out wide-spread and severe contamination by spent ammunition.
NAVMAG11 Ammunition Disposal Burning Pit
Location of most likely areas of contamination are not known.
Targeted sampling was supposed to address the most likely areas of contamination. At Site 11 the locations of the three suspected source areas (open-air detonation area, open-air burning area, underwater disposal area) are not known.
Information on removal of contaminants from the site is unknown.
The EQS states that the area was scraped periodically and metal transferred to the DRMO for recycling. The EQS does not describe the process for separating scrap metal from potentially contaminated soils. After removing scrap metal, the disposal method for the scraped soil was not provided. Based on the lack of information, contaminated soil could be potentially found anywhere in vicinity of Site 11.
Potential of random sampling to overlook Òhot spotÓ.
The gridded sample pattern used on the eastern portion of the site uses spacings of 30 meters by 50 meters (100 by 165 feet). This means a ten percent chance of overlooking a "hot spot" of 1/3 of an acre in area. It is likely that the principal sources areas at Site 12, the explosive detonation and burn pits, had smaller dimensions. It is possible that the principal source areas were not sampled.
The exceedance of PRGs for lead and RDX need to be fully investigated.
Further action has been recommended at this site to address potential UXO which may have been both buried at the site as well as disposed of in the waters of Subic Bay. An estimated 1,000-10,000 cubic meters of soil is recommended for excavation, stabilization and disposal in the Subic Bay landfill (Site 45). The estimated cost of this action ranges from $16,000 to $160,000 US dollars. Given the wide range of cost estimates the depth and lateral extent of the identified contamination at Site 11 should be investigated in greater detail before initiating any remedial action.
NAVMAG12 - Demilitarization Facility
Previous Activities.
The historical information for this site begins in 1981. Prior use of the site area is not described. Methods of disposal for small arms, shells, grenades, bombs, lithium batteries, and chemical warfare decontaminating agents prior to the construction of the demil facility are not provided. These historical disposal practices may have left an impact on the Site 14 and Site 45 landfill sites.
Air pollutant deposition from hazardous waste incinerator not investigated.
The demil facility at Site 12 disposed of hazardous wastes using a rotary furnace from 1981 until its closure. The demil facility may have produced hazardous air emission containing heavy metals. It is likely given the topography in the area of the demil facility that hazardous pollutants present in air emissions deposited in the areas surrounding Site 12. These potential off-site impacts should be investigated.
Potential impacts from surface water run-off not investigated.
The EQS indicates that high levels of heavy metals found in sample SS02 may be related to surface water runoff from the demil facility. The extent of impacts from surface water run-off should be further investigated.
Recommended remediation.
The EQS recommends the removal of small quantities of ash from Site 12. A total of 500 to 1,000 cubic meters. This material would be stabilized and disposed of in the existing landfill at a cost of $5,000 to $16,000 US dollars.
Further investigation and remediation work would be required at this site to determine the full extent of metals contamination. The EQS therefore likely underestimates the cost required to address contamination at this site.
NAVMAG13 - Wood Treatment Facility
Tank integrity information not provided.
No information on the underground dip tanks integrity are provided. The shallow depths of soil samples would not detect wide-spread and severe contamination if it resulted from a sub-surface tank leak. The EQS does not provide information on how "drag-out" from the dip tank was collected and handled. Soil sample locations do not appear to target areas potentially impacted by tank "drag-out."
Further investigation of this site is warranted.
"There remains a possibility that contamination may be present in soils further down slope from the site." The site reconnaissance and sampling plan failed to address this area down-slope from Site 13 that has a high potential for contamination.
Inconsistencies in reported sample results.
"Confirmation sampling and analysis was not required for this site." (p. 14-2) Confirmation sampling results are, however, reported in Table 13.2.1. Results of TPH analysis from the initial sampling round were not reported. Results from the confirmation round indicate that petroleum hydrocarbons (C15-C28 fraction and C29-C36 fraction) were not analyzed in 2 of 3 of these samples. Equally odd is the dates of the initial and confirmation samples. The initial sampling round occurred in 9/10/95. The confirmation sampling round seven months earlier, on 2/07/95.
NAVMAG43 - Air Underwater Magazine
Chemical of Concern, Otto Fuel, not included in analysis scope.
A review of analysis results, indicate that the components of Otto fuel were not included in the analysis scope. Instead of analysis of Otto fuel components a general scan for TPH was performed.
Screening limits for Otto Fuel components not provided.
This TPH analysis indicated soils throughout Site 43 were contaminated. Based on site history it is appropriate to suspect that the detected TPH is in fact Otto Fuel. No other hazardous materials were reportedly stored and used at the site. The EQS uses the TPH screening limits to evaluate data for Site 43 without justifying that the screening limit developed for petroleum fuels sold at gas stations is appropriate for spills of torpedo fuel.
