Environmental Investigations and Research

Environmental Investigations and Research

To date, the U.S. Army has invested significant resources to investigate the munitions present at Ordnance Reef, Sea Disposal Site Hawai‘i 6 (HI-06), their potential impacts to human health and the environment and to adapt existing technologies for the recovery and destruction of munitions. Ordnance Reef (HI–06) has been the subject of multiple investigations; these include the 2002 survey of munitions items by the U.S. Navy Explosive Ordnance Disposal Detachment, a 2006 screening-level survey conducted by the National Oceanic and Atmospheric Administration (NOAA) and the University of Hawai‘i (UH), a study conducted in 2009 by the Department of Defense (DoD) and UH to fill data gaps in the 2006 NOAA screening-level survey, a 2011 Technology Demonstration, and a 2013 Follow-up Environmental Investigation.

NOAA Screening-level Survey

In 2006, the U.S. Army and U.S. Navy funded NOAA to conduct a screening-level survey of Ordnance Reef (HI-06) to determine the environmental implications from the presence of discarded military munitions. The NOAA survey, which was limited to depths of approximately 25 to 300 feet (7 to 91 meters), determined both the boundaries of Ordnance Reef (HI-06) and the locations of underwater military munitions (UWMM) present, provided information for use in identifying the types and approximate quantities of UWMM detected, and analyzed sediment and fish tissue samples for munitions constituents (i.e., metals and explosives). Many of the UWMM observed were heavily fouled with algae and benthic organisms. In some cases, munitions had substantial coral growth on them. NOAA released its independent report in 2007. The report, which provided the DoD with screening-level data, also provided the basis for assessing the potential explosives safety and human health or ocean environmental risks associated with the UWMM present and for making a determination of whether a response was required.

The U.S. Army’s and U.S. Navy’s explosives safety centers concluded that the UWMM present did not pose an immediate explosives safety risk to the public, and only deliberate activities (e.g., divers disturbing the UWMM) posed a threat to those who use Ordnance Reef (HI-06) for recreational-related and other activities. The DoD Explosives Safety Board endorsed this conclusion. The U.S. Army, as part of its 3Rs (Recognize, Retreat, Report) Explosives Safety Education Program (Recognize–when you have encountered a munition and that munitions are dangerous, Retreat–do not approach, touch, move or disturb it, Report–call 911) implemented a comprehensive public education effort that focused on, but was not limited to, the communities near Ordnance Reef (HI-06) (i.e., Wai'anae and Nýnýkuli).

The U.S. Army Center for Health Promotion and Preventive Medicine, now the U.S. Army Pubic Health Command, and the U.S. Navy and Marine Corps Public Health Center, the agencies responsible for health and environmental risk assessments, concluded that the contaminant levels from any munitions constituents detected were all well below risk-based levels; and the only metals detected in fish tissue did not appear to be munitions constituents associated with the UWMM present at Ordnance Reef (HI-06). Based on available data, these assessors concluded that it was unlikely that the UWMM posed an unacceptable health risk to humans. The ecological evaluation found no overt signs of stress or ecological impact. However, both agencies concluded that there were data gaps that needed to be addressed to answer the community's questions regarding possible risk to human health and/or the potential contamination of marine food resources.

The U.S. Department of Health and Human Services, Center for Disease Control, Agency for Toxic Substances and Disease Registry (ATSDR) performed a health consultation for Ordnance Reef (HI-06) based on the NOAA report. The ATSDR report which identifies ingestion of biota as the most significant way people could contact chemicals, concluded contact with chemicals (i.e., munitions constituents) in sediments would not be of sufficient frequency to present a hazard by ingestion or dermal (skin) contact. ATSDR indicated that inorganic chemicals detected in fish tissue are not a public health hazard (note that no explosive munitions constituents were detected in fish tissue). ATSDR identified several metals that although not detected in the samples could pose a public health risk if present near the analytical detection limits.

After review of the NOAA report, the U.S. Army determined that data gaps existed that would need to be addressed to make a definitive determination as to whether the UWMM at Ordnance Reef (HI-06) posed a risk to human health and the ocean environment. In December 2007, the U.S. Army tasked the U.S. Army Corps of Engineers (USACE), Pacific Ocean Division to work with state agencies and potentially affected communities using its technical project planning process to identify study questions that a follow-on investigation should answer; and determine the steps and information required to close the data gaps and reach a valid answer to those questions. In January 2008, USACE held an initial meeting with the Ordnance Reef Coordinating Council that the U.S. Army established, on behalf of the DoD, to review the NOAA screening-level survey report and related documents, and to consider courses of action to address community concerns about the UWMM present at Ordnance Reef (HI-06). The Ordnance Reef Coordinating Council activities are discussed in more detail on the Public Participation tab.

Ordnance Reef - NOAA Study - Report - 2007 (PDF, 5.5MB) pdf [5.74 MB]
Ordnance Reef - NOAA Study - ATSDR HC - 2007 (PDF, 87.6KB) pdf [89 KB]
Project Area - Maili Beach Park   propellant grain from Maili Beach

Propellant grains were reported washing ashore Mý‘ili Beach and nearby areas (south of Ordnance Reef (HI 06)) for many years. To address community concerns, the U.S. Army implemented sweeps along the coast over a four-year period starting in 2007. During this period, the Army’s contractor recovered 1,432 propellant grains (each approximately 1 inch in length) along Mý‘ili Beach and beach parks north and south of Mý‘ili Beach Park. Initially, regular sweeps of the beach were conducted to collect any propellants gains observed. However, these sweeps did not result in a recovery of very many propellant grains. Because propellant grains seemed to only be washing ashore under certain conditions, the Army revised its approach focusing on specific tidal areas and conditions, and responding only when propellant grains were observed or encountered and reported. This approach and implementation of a 3Rs (Recognize, Retreat, Report) explosives safety education program that targeted propellant grains, proved to be much more efficient. The education trained lifeguards how to address propellant grains observed or encountered. It also informed the public not to collect or handle propellant grains and that these grains are highly flammable.

miniature of a UXO poster, too small to read

University of Hawai'i Environmental Study

Following the NOAA screening-level survey, the U.S. Army contracted UH to conduct the Environmental Study, which included sampling (sediment, water column and biota), to answer the concerns of affected communities about whether seafood from the area is safe to eat. In its study, UH:

• Focused on the NOAA survey study area (Ordnance Reef (HI-06)), including areas up to the shoreline;
• Closed data gaps about the human health risk potential posed by the munitions present; and
• Investigated the site conditions further using an established process for environmental investigations.

The Environmental Study team collected sediment, seawater, and biological samples in four different strata (locations: discarded military munitions [DMM], control [CON], non-point source [NPS], and wastewater treatment plant [WWT]) to assess areas with and without discarded military munitions that had a potential for non-discarded military munitions sources of contamination. Within each of the four strata, four sample sites were randomly selected. The Environmental Study team analyzed the samples for a number of chemicals of potential concern, including: nine energetics (explosive-related compounds), five phthalates (plasticizers) and pyrene, and three heavy metals. A total of 18 seawater samples, 59 sediment samples, and 179 biological samples were collected for this Environmental Study. UH completed its field work, conducting sampling during two timeframes April, and September–October 2009.

Two energetic compounds were detected in sediments: 2,4-DNT (dinitrotoluene) and 2,6-DNT. These are the same two compounds detected during the NOAA screening-level survey, but concentrations detected in 2009 were much lower than those detected in 2006. There was no clear and consistent correlation evident between the concentration of energetic compounds and the distance from the discarded military munitions. Neither compound was present at concentrations exceeding project action limits. Because of the low concentrations of these two energetics detected during the UH Environmental Study, and because it is unlikely people will come into regular contact with sediments, energetics in sediment were not considered to pose a human health risk.

The UH Environmental Study detected a single phthalate, bis(2-ethylhexl)phthalate, in a seawater sample collected from the Wai'anae WWT stratum. The concentration detected was well below the screening levels for this constituent for ecological receptors. A di-n-butyl phthalate detection occurred in a biological sample. The di-n-butyl phthalate was detected in a duplicate sample, but it was not detected in the corresponding primary sample. There were no other phthalates or pyrene detections in any of the seawater or biological samples.

Several energetic compounds were detected in biota samples collected from Ordnance Reef (HI 06): 2,4-DNT, HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), 2-NT (2-nitrotoluene), 4-NT (4-nitrotoluene), RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), tetryl and 1,3,5-TNB (1,3,5-trinitrobenzene). Detections occurred primarily in fish samples, although one octopus and one crab also contained at least one energetic compound. These data were carefully considered in both the human health risk assessment and the ecological risk assessment.

Samples collected from the DMM stratum typically showed higher abundances of copper and lead than those collected from the other strata, while concentrations of arsenic were higher in sediments from the control (CON, or background) stratum than from other strata. Although there is community concern with respect to arsenic, this element is not abundant in conventional munitions and it was not expected that arsenic would be enriched in sediments from the DMM stratum. The finding of arsenic in sediments from the CON stratum indicates that this element is derived from land-based input through runoff. As with energetics, there was no clear and consistent correlation evident between the concentration of metals in sediment and the distance from the discarded military munitions.

In general, metals were detected at similar levels in all biological samples from each stratum. Notable exceptions to this finding were copper and zinc, which were considerably enriched in seaweed collected in the DMM stratum. Concentrations of arsenic in biological samples were remarkably similar across the various strata. Furthermore, the overwhelming majority (approximately 99%) of arsenic was present in the less toxic organic form, in crab, octopus, and fish.

The results of the ecological risk assessment, using the Ordnance Reef (HI-06) Environmental Study data, indicate risk from energetic compounds and barium was acceptable for sediments. Potential risks to ecological receptors from exposure to lead and zinc in sediment were low and are probably negligible. Potential risk from copper in sediment was moderate.

The potential for risk to fish-eating (piscivorous) seabirds feeding at the DMM stratum are insignificant. The concentrations of compounds of potential ecological concern (COPECs) in fish samples from the Ordnance Reef (HI-06) Environmental Study did not exceed critical tissue levels for fish when such values were available; however, tissue-based screening levels were only available for three of the ten COPECs detected in the fish samples (4-NT, RDX, and lead). No tissue-based screening levels were found for the COPECs detected in the other biota specific to those taxa (e.g., crabs, octopus, seaweed).

In summary, the human health risk associated with the consumption of seafood from the DMM stratum, based on the Ordnance Reef (HI-06) Environmental Study findings, was similar to those of the other strata. The exception was the “high-end” consumer, with the assumption that the “high-end” consumer eats seafood collected almost exclusively from the DMM stratum. This scenario is extremely unlikely, yet was chosen to assess the worst-case scenario for seafood consumption along the Wai‘anae coast. Even with such consumption, it is highly likely that the benefits of consuming seafood (as opposed to a high fat content diet, for example) far outweigh the risk associated with seafood from the DMM stratum. For the average Wai‘anae community consumer, whose seafood consumption habits are greater than most Hawai‘i residents and far greater than that considered typical of U.S. citizen consumption, there is no significant risk associated with consuming seafood from the discarded military munitions or the other strata. It should be kept in mind the U.S. Food and Drug Administration routinely recommends moderate seafood consumption to limit ingestion of mercury that is associated with certain high-end predatory fish found throughout the world’s oceans. A similar recommendation is likely warranted here.

Ordnance Reef - Environmental Study - Report Text (PDF, 4.4MB) pdf [4.60 MB]
Ordnance Reef - Environmental Study - Appendices except Appx H (PDF, 4.4MB) pdf [4.60 MB]

NOAA Ocean Current Study


Ocean Circulation and Predictive Modeling Study

The Ocean Circulation and Predictive Modeling Study (Current Study) was conducted by NOAA, DoD and UH at Ordnance Reef (HI-06). The Current Study was designed to gain a better understanding of the oceanographic forces affecting munitions and bulk containers, and to model the fate and transport of munitions-related compounds at Ordnance Reef (HI-06) and a second deep-water chemical warfare materiel disposal site (Area 1 (HI-01)) 10 miles to the west. Such data are important for determining the potential human health and ocean environmental risks posed by UWMM. Between July 2009 and August 2010, sensors (acoustic Doppler current profilers (ADCPs)) continuously monitored and recorded current speed and direction. NOAA deployed four bottom-mounted ADCPs in the shallow waters at Ordnance Reef (HI-06) and a string of five ADCPs at a depth of about 8,200 feet (2,500 meters) at HI-01. The current data were put into UH numeric ocean circulation models developed as a part of the Hawai‘i Ocean Observing System. Computer models describing ocean circulation patterns and predicting the movement and fate of munitions related compounds from the sites used these data.

Working with UH, NOAA analyzed the data from the Current Study to determine the seasonal characteristics of the current, speed and direction throughout the water column, and it developed a larger computer model to represent the spatial variability of currents within the study region. NOAA also collaborated on development of computer models that provide simulations of the chemical interactions of munitions-related compounds with the ocean water and movement of those compounds should a release occur.

The data collected by the ADCPs indicated that the primary circulation along the west coast of O‘ahu is along-shore because of the dominance of the semi-daily and daily tides. Particles in this system are moved north and south along the coast, with weak on- and off-shore motion as the tides change from ebb to flood. During typical periods, current flow is primarily along-shore (clockwise-flowing eddies on the shore will push particles along-shore towards the south). This summary matches the general understanding of currents and tides in the vicinity of Ordnance Reef (HI-06).

Ordnance Reef - NOAA Current Study  2012 (PDF, 19.6MB) pdf [20.57 MB]

Coral Avoidance and Minimization of Injury

In 2010, the U.S. Army obtained federal interagency support from NOAA to develop a Coral Avoidance and Minimization of Injury Plan to help avoid or limit (minimize) injury to coral and other benthic habitats, and identify mitigation measures should coral be affected during the U.S. Army’s technology demonstration. NOAA believed that remotely operated underwater vehicle activities (e.g., dragging the tether, positioning the remotely operated vehicle for recovery, recovery of munitions) and mooring activities for both the remotely operated vehicle support vessel and demilitarization support vessel posed the greatest risk of injury to coral. The coral avoidance and minimization of injury efforts occurred in three phases:

  • Phase I: Pre-demonstration survey of corals and munitions and assistance with development and review of best management practices;
  • Phase II: Post-recovery survey to assess impacts to coral, loss of corals from munitions recovery, and recommend mitigation strategies for those impacts; and
  • Phase III: Completion of required coral mitigation activities by the U.S. Army (not yet completed).

NOAA conducted 78 survey dives covering about 72 acres for Phase I and took 1,862 photographs of UWMM and habitat types. NOAA, in coordination with the Army, selected three work areas to be the focus of the technology demonstration, Work Area A, B and C. The three work areas are known areas of higher UWMM densities based on the underwater surveys conducted in 2002, 2006 and as part of the development of the Coral Avoidance and Minimization of Injury Plan. The Fish Haven was selected for the mooring location of the barge for destruction of the recovered munitions. Within areas designated for remotely operated underwater vehicle operations, NOAA surveyed approximately 52 acres (roughly 18% of the three work areas).

The Fish Have

NOAA divers photographed and calculated approximate geographic coordinates for roughly 21,200 munitions. NOAA completed Phase I in March 2011. Phase I findings and recommendations were compiled in the Coral Avoidance and Minimization of Injury Plan. This Plan addresses the relative risk of coral injury in three work areas based on relief of the area, abundance of coral present, and presence of corals of high ecological value. This enabled the U.S. Army to anticipate and thus avoid or minimize possible demonstration-related coral injuries. NOAA’s assistance allowed the U.S. Army to guide placement of moorings and anchorages, direct recovery efforts, and develop and use best management practices throughout the Technology Demonstration. To reduce potential coral injuries during the Technology Demonstration, priority was given to the recovery of munitions in areas of uncolonized hard bottom and sand while exercising caution in areas of higher coral cover. The Coral Avoidance and Minimization of Injury Plan also included possible emergency restoration efforts to reattach corals that might become dislodged during recovery activities.

During Phase II, NOAA assessed injuries that occurred to coral during the Technology Demonstration. The results of NOAA’s post-recovery survey determined that such injuries were minimal and identified recommendations for restoration to compensate for the Technology Demonstration-related injuries. Phase III will entail the U.S. Army’s actions to address the coral injuries discovered during Phase II. These actions will consider NOAA’s recommendations in selecting the mitigation measures.

Ordnance Reef - NOAA Coral Injury Assessment and Mitigation Recommendation  2013 (PDF, 1.2MB) pdf [1.22 MB]

U.S. Army Technology Demonstration

In 2011, the U.S. Army Environmental Quality Technology program conducted the Technology Demonstration at Ordnance Reef (HI-06). The U.S. Army obtained support from NOAA who ensured adequate protection of coastal marine resources was provided for during the Technology Demonstration and identified mitigation. The U.S. Army demonstrated two primary technologies at Ordnance Reef (HI-06): one to remotely recover UWMM and another to treat (demilitarize) recovered UWMM at sea. These technologies are the Remotely Operated Underwater Munitions Recovery System (ROUMRS) and the Explosive Hazard Demilitarization System (EHDS). The Technology Demonstration also provided an opportunity to evaluate several additional technologies for non-destructive testing, and explosives detection.

ROUMRS consists of a standard work class underwater remotely operated underwater vehicle, manipulators, an interface between a precision global positioning system (GPS), and underwater navigation equipment used during recovery of UWMM. The system also transports recovered UWMM for treatment. The EHDS consists of a portable X-ray unit to allow positive identification of recovered munitions, remotely operated wet band saws to cut recovered munitions to expose their explosive fill, and low-temperature ovens to treat the exposed explosives, making the remaining material safe for recycling.

ROUMRS  model ROUMRS  diagram

The Technology Demonstrations for ROUMRS and EHDS began on 11 July 2011. ROUMRS activities concluded on 30 July 2011 and EHDS activities concluded on 3 August 2011. The Technology Demonstration occurred in waters from approximately 30 to 130 feet (9 to 40 meters) deep.

ROUMRS image 1 ROUMRS image 2 ROUMRS image 3

During the Technology Demonstration, ROUMRS recovered 2,300 small arms ammunition items and attempted to recover 218 items that appeared to be UWMM of various calibers (small-, medium- and large caliber munitions). However, given the coral encrustation, which cemented 138 items to the ocean floor, ROUMRS was only able to recover 80 items. Of these, 74 were munitions. The EHDS successfully treated the 74 munitions recovered, destroying 330 pounds (150 kilograms) of explosives, 135 pounds (61 kilograms) of propellant, and all 2,300 recovered small arms ammunition items.

The Ordnance Reef (HI-06) Technology Demonstration confirmed that ROUMRS can remotely recover UWMM and has distinct operational advantages over the use of divers. Additionally, the use of ROURMS improves the overall safety of recovery operations and decreases costs due to increased personnel safety. EHDS provides an efficient, safe, and environmentally sound means of treating recovered munitions, both at sea and on land, reducing reliance on open detonation. ROUMRS and EHDS each provide munitions response options that improve public safety, reduce the potential for damage to the environment, and remove explosive hazards without the risks associated with diving operations.

ROUMRS process steps versus EHDS process steps

Ordnance Reef - Tech Demo - Systems Requirements Report - 2009 (PDF, 519KB) pdf [531 KB]
Ordnance Reef - Tech Demo - EA Complete - 2011 (PDF, 16.9MB) pdf [16.88 MB]
Ordnance Reef - Tech Demo - EA wo-Appendixes - 2011 (PDF, 3.3MB) pdf [3.42 MB]
Ordnance Reef - Tech Demo - FNSI - 2011 (PDF, 376.1KB) pdf [385 KB]
Ordnance Reef - Tech Demo - Report Text - 2012 (PDF, 3.8MB) pdf [3.94 MB]
Ordnance Reef - Tech Demo - Report Appendices - 2012 (PDF, 13.1MB) pdf [13.79 MB]

U.S. Army Corrosion Study

Relatively little is known about the corrosion behavior and rates for UWMM, making it difficult to assess the timeline for and nature of casing breaches due to corrosion. These breaches lead to the release of explosives and propellants into the marine environment. The recovery of munitions during the Technology Demonstration provided a unique opportunity to study the corrosion of munitions that have been underwater for an estimated 60 years or more.

Conduct of the Corrosion Study is helping in understanding how corrosion affects munitions both when buried on land and in the marine environment. With regard to UWMM, metal corrosion begins from the moment metal contacts seawater and is quickest near the beginning of environmental exposure. The reaction rate depends on the temperature, oxygen concentration, quality, and type of metal in the munition and water currents at the disposal site. Examination of sea-disposed munitions indicates that the metal casings are degraded by saltwater contact, but environmental factors have a significant influence on the rate of corrosion. Investigations of sea-disposal sites have found both intact and completely corroded casings that do not contain a fill in a given area. This lends confidence to the position that corrosion rates are highly variable, even over short distances.

The U.S. Army collected data to develop an initial understanding of corrosion mechanisms and to enhance its capability to predict the failure of munitions casings. This will support site management decisions, and aid in validating environmental impacts of UWMM on the marine environment. During its Technology Demonstration, the U.S. Army collected the metal from a variety of munitions after EHDS treatment for study. The munitions’ pieces and, in some cases, encrustation were bagged and tagged with recovery depth and other pertinent information for study. During the Technology Demonstration, the corrosion found on many munitions was more extensive than expected. Some munitions’ bodies were found to be partially deteriorated. In at least one case, a munitions’ body was completely deteriorated, leaving only an encrustation of coral and other organisms.

Ordnance Reef - Corrosion Study - 2015 (PDF, 2.6MB) pdf [2.68 MB]

University of Hawai'i Follow-Up Investigation

The Follow-Up Investigation involved three rounds of sampling between 2011 and 2013 to evaluate whether the recovery of UWMM from Ordnance Reef (HI-06) during the U.S. Army’s Technology Demonstration had an impact on the concentrations of munitions constituents present in the marine environment. Sampling sediment and biota in four strata (DMM, CON, NPS, and WWT), and allowed the comparison of pre- and post- technology demonstration conditions.

The samples collected during the Follow-Up Investigation matched those collected for the UH Environmental Study to allow a direct comparison of the results. The primary focus of sample site selection was to target the collection of biota and sediment samples in close proximity to the munitions recovered during the Ordnance Reef (HI-06) ROUMRS Technology Demonstration to assess the possible changes from the recovery of the munitions. Sampling occurred during and one week after the ROUMRS Technology Demonstration, about one year later, and finally nearly two years later. UH collected a total of 88 sediment samples from the four strata and a total of 108 biota samples consisting of 44 fish, 26 octopus, 15 crab and 23 seaweed. In addition to analyzing these samples for elements (munitions related and unrelated) and energetics, the study also determined the form of arsenic present (toxic inorganic versus nontoxic organic arsenic). Using a variety of sophisticated statistical techniques the scientists were able to look for patterns in complex data, quantify the relationships between analytes, and compare pre- and post-ROUMRS data.

The scientists completed a comparison of sample results prior to the Technology Demonstration to results from sampling after the ROUMRS Technology Demonstration. Arsenic was significantly higher in post-ROUMRS crabs but significantly lower in post-ROUMRS octopus. There was also significantly lower zinc in the post-ROUMRS octopus. Post-ROUMRS copper and zinc were significantly higher in fish but so were chromium, and strontium. Post-ROUMRS arsenic, lead, and vanadium were significantly lower.

In the statistical analysis of both pre- and post-ROUMRS sediment data, four elements (copper, lead, zinc, and magnesium) were clearly associated with munitions, in addition to the energetics. It is surmised that brass shell casings were the source of much of the copper and zinc, small arms ammunition slugs with lead, and tracer rounds with magnesium. Arsenic, on the other hand, was more closely associated with the terrestrial elements (e.g., aluminum, chromium, iron), the source is possibly terrestrial runoff from O‘ahu. Not surprisingly, copper, zinc, and lead were generally higher in the DMM stratum, whereas arsenic and the terrestrial elements were higher in the CON stratum.

Statistical analysis of the biota data revealed that there was a clear pattern in the data by organism type; however, only the limu (seaweed) data showed a possible pattern associated with strata. The crab and octopus clustered somewhat together, whereas the fish and limu formed distinct and separate clusters. Not only did the crab and octopus cluster together but they also clustered with copper which is not surprising given that their blood contains copper-based hemocyanin. Arsenic and zinc were highest in crabs and lead was consistently detected in limu. A consistent and strong correlation existed between copper and zinc for all organisms presumably because of the presence of copper- or zinc-based enzymes. With the exception of limu, toxic inorganic arsenic was not detected in organisms.

Using another statistical test, pre- and post-ROUMRS sediment data from both the DMM and CON strata was compared. Most analytes were significantly lower in the post-ROUMRS data; there were exceptions (e.g., calcium). While it would be tempting to say that this decrease was the result of recovering the munitions, the fact that analytes that were not associated with DMM were also lower as were post-ROUMRS data from the CON stratum, suggests that there may be other factors that caused the observed difference. There also was no clear pattern in the biota data with some post-ROUMRS analytes higher and others lower depending on the organism. Therefore, while the study’s results indicate that post-ROUMRS analyte concentrations in sediment were significantly lower, they do not necessarily attribute this to the ROUMRS Technology Demonstration.

A comparison of plots for the pre- and post-ROUMRS sediment data found that the correlations between analytes from post-ROUMRS data seem to be somewhat less. Interpretation of the meaning of this, at this point, is purely conjecture without additional investigation. Given that the munitions were on the seafloor and, hence, in contact with the sediments for decades, it is possible that the chemicals that made up the casings, explosives, and propellants had reached pseudo-equilibrium with their environment. It is possible that in recovering some of the discarded military munitions, this equilibrium was disturbed and, as a result, the correlations are no longer as strong as they were in the pre-ROUMRS data. Proving this hypothesis would require further testing. There could be a number of other reasons why pre- and post-ROUMRS sediment data differ.

The results of the biota sampling were, if anything, less clear. First, plots of the pre- and post-ROUMRS biota data showed that the data clustered by organism and, with the exception of the pooled pre- and post-ROUMRS limu data, not by stratum. Moreover, unlike the sediment data, there was no clear relationship between the analytes except for a consistent positive correlation between copper and zinc. The study team attributed this correlation to the existence of copper- or zinc-based enzymes in the organisms. Generally, differences in pre- and post-ROUMRS analyte concentrations in limu were not significant, particularly those analytes associated with discarded military munitions such as copper, lead, and zinc. Likewise, these elements were not significantly different in crabs but possibly any effect of copper would have been masked by the hemocyanin. Copper and zinc were significantly lower in post-ROUMRS octopus as was cobalt; chromium was significantly higher. Copper and zinc were significantly higher in post-ROUMRS fish but lead was significantly lower. Also, post-ROUMRS arsenic was lower but chromium was higher. So while there were significant differences, the analytes were not consistently lower or higher in post-ROUMRS biota. In summary, the study team did see significant differences between pre- and post-ROUMRS sediment and biota data. Nonetheless, it is difficult to say that these differences resulted from the ROUMRS Technology Demonstration and, in fact, the data suggest that there were other, unknown factors that may have contributed to these differences. While the sediment data did not explain the differences, it was apparent that sediment data are at least more consistent than biota data. On the other hand, the biota data needed to be collected to determine what munitions constituents might be ingested by humans.

Ordnance Reef - FUI  Report (PDF, 9.9MB) pdf [10.33 MB]
Ordnance Reef - FUI - Appendices except E (PDF, 19.6MB) pdf [20.52 MB]