Underwater Munitions Research Articles

BEHAVIOR OF VARIABLE DENSITY MUNITIONS UNDER DAM BREAK FORCING

Munitions or Unexploded Ordnance (UXO) are ammunitions belonging to a larger family of explosives from past military activities. Sea disposal of munitions was a common practice from the late 1800s to 1970 when international conventions put an end to the practice. The exact quantity of munitions dumped into the Oceans globally is unknown due to sparse documentation but conservative estimates of known records stand at 1.6 million tons (Wilkinson, 2017). After decades underwater, some munitions have resurfaced in the nearshore, presumably washed onshore or exhumed by high-energy wave action. Extreme events could be major causes of migration and exposure of UXO in the nearshore. The quantification of variable density munitions behavior in the swash zone remains poorly understood. Biofouling, encrustation, and corrosion can alter the density of the underwater munitions, which consequently impacts the behavior of the munitions in the swash zone. Hence, this experimental study aimed to quantify the behavior of variable density munitions in the swash zone under dam-break scenarios. The findings of the study create more insights into the behavior of variable density munitions in the swash zone and can also serve as validation data for probabilistic models on munitions behavior in the swash zone under extreme events.

Application of Neural Network Technologies for Underwater Munitions Detection

Application of Neural Network Technologies for Underwater Munitions Detection

Effects of salinity and temperature on seawater dissolution rate of initial detonation agent mercury fulminate

Mercury fulminate (HgFu) was used as an initial detonator for World War I and II munitions. Its presence in previously discarded and dumped munitions could potentially supply mercury pollution into coastal ecosystems where bygone weaponries reside. There is evidence that historical munitions have already contributed mercury pollution in coastal environments, and millions remain embedded in sediments and subjected to further weakening via corrosion under environmental conditions. Experiments were undertaken assessing HgFu dissolution under varying temperature and salinity conditions to constrain controls on mercury release into marine environments. Our results show that HgFu discharge is strongly temperature dependent, with dissolution rate constants increasing from ∼0.4 mg cm−2 d−1 at 5 °C to ∼2.7 mg cm−2 d−1 at 30 °C. No significant differences were observed between freshwater and seawaters up to 36 psu, except at 5 °C. These experiments provide a basis for modeling HgFu release from underwater munitions and its dynamics in coastal environments.

Environmental Characterization of Underwater Munitions Constituents at a Former Military Training Range.

As a result of military activities, unexploded ordnance and discarded military munitions are present in underwater environments, which has resulted in the release of munitions constituents including the high explosives 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), along with their primary degradation products, to the water column and adjacent sediments. The present study focused on the characterization of underwater exposure and concentrations of energetics such as TNT and RDX at the former Vieques Naval Training Range at Bahia Salina del Sur (Vieques, Puerto Rico, USA), a bay with documented high incidence of munitions. In situ passive sampling using polar organic chemical integrative samplers (POCIS) was used for the detection and quantification of constituents in water at target locations approximately 15 to 30 cm from 15 individual potentially leaking munitions, and also at 15 unbiased locations approximately evenly spaced across the Bay. For comparison with POCIS-derived concentrations, grab samples were taken at the POCIS target locations. The POCIS-derived and averaged grab samples agreed within a factor of 3. When detected, munitions constituent concentrations (primarily TNT and RDX) were observed at ultratrace concentrations (as low as 4 ng/L for RDX), except 30 cm from one General Purpose bomb where the TNT concentration was 5.3 µg/L, indicating that low-level contamination exists at Bahia Salina del Sur on a very localized scale despite the relatively high density of munitions, similar to previously reported results for other munitions sites around the world. Sediment and porewater sampled at 4 stations where munitions constituents were detected in the water column had concentrations below detection (approximately 5 µg/kg and 5 ng/L, respectively), suggesting that the sediment was not a sink for these constituents at those locations. Environ Toxicol Chem 2022;41:275-286. © 2021 SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Missing from the record: historians, archival research and underwater munitions

ABSTRACT Archival research is an important starting point for scientific studies on underwater munitions, but marine scientists have voiced concerns and criticism over the completeness, validity, and reliability of historical records. However, labelling primary sources as ‘incomplete’ demonstrates that scientists have largely misunderstood how and why archives accumulate information. This article seeks to familiarize readers with the benefits and challenges of archival research on underwater munitions. It explores the role of the archives in preserving historical sources and offers explanations as to why ‘gaps’ in information develop over time. In doing so, it elucidates how the archival grain was shaped by a variety of factors and actors over time, and shows how ‘gaps’ emerged from more than just national security, military secrecy, information laws, and archival science. The agency of past scientists, historians, bureaucrats, and private military contractors all played a role in shaping the nature of documentation about this concerning legacy of war and military pollution.

The use of historical evidence in studies on underwater munitions

Marine scientists and other experts depend on information found in archival documents and other historical records to investigate underwater munitions. These sources help them locate dumpsites, establish timelines, identify ordnance, and better understand the hazards, chemicals, and degradation products found in their studies. However, historical sources do not always satisfy these needs, and can sometimes lead investigators down convoluted, incomplete, and misleading trails of evidence. This article seeks to provide scientists with some advice about conducting archival research and interpreting meaning from historical sources by recounting the history of a dumping operation that never happened over the summer of 1921. In doing so, this article demonstrates the value of historical perspectives and research methodologies, and encourages scientists to better integrate historical evidence into their work and seek out more collaborative opportunities with historians.

In Situ Measurements of Explosive Compound Dissolution Fluxes from Exposed Munition Material in the Baltic Sea

Underwater munitions containing millions of tons of toxic explosives are present worldwide in coastal marine waters as a result of unexploded ordnance and intentional dumping. The dissolution flux of solid explosives following corrosion of metal munition housings controls the exposure of biological receptors to toxic munition compounds (MC), including TNT: 2,4,6-trinitrotoluene, RDX: 1,3,5-trinitro-1,3,5-triazinane, and DNB: 1,3-dinitrobenzene. Very little is known about the dissolution behavior of MC in the marine environment. In this work, we exploit a unique marine study site in the Baltic Sea with exposed solid explosives to quantify in situ MC dissolution fluxes using dissolved MC gradients near the exposed explosive surface, as well as benthic chamber incubations. The gradient method gave dissolution fluxes that ranged between 0.001 and 3.2, between 0.0001 and 0.04, and between 0.003 and 1.7 mg cm-2 day-1 for TNT, RDX, and DNB, respectively. Benthic chamber incubations indicated dissolution fluxes of 0.0047-0.277, 0-0.11, and 0.00047-1.45 mg cm-2 day-1 for TNT, RDX, and DNB, respectively. In situ dissolution fluxes estimated in the current study were lower than most dissolution rates reported for laboratory experiments, but they clearly demonstrated that MC are released from underwater munitions to the water column in the Baltic Sea.

Field validation of POCIS for monitoring at underwater munitions sites.

The present study evaluated polar organic chemical integrative samplers (POCIS) for quantification of conventional munitions constituents, including trinitrotoluene (TNT), aminodinitrotoluenes, diaminonitrotoluenes, dinitrotoluene, and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in a field setting. The POCIS were deployed at varying distances from the commonly used explosive formulation composition B (39.5% TNT, 59.5% RDX, 1% wax) in an embayment of Santa Rosa Sound (Pensacola, FL, USA). Time-weighted averaged water concentrations from a 13-d deployment ranged from 9 to 103 ng/L for TNT and RDX, respectively, approximately 0.3 to 2 m from the source. Concentrations decreased with increasing distance from the source to below quantitation limits (5-7 ng/L) at stations greater than 2 m away. Moderate biofouling of POCIS membranes after 13 d led to a subsequent effort to quantify potential effects of biofouling on the sampling rate for munitions constituents. After biofouling was allowed to occur for periods of 0, 7, 14, or 28 d at the field site, POCIS were transferred to aquaria spiked with munitions constituents. No significant differences in uptake of TNT or RDX were observed across a gradient of biofouling presence, although the mass of fouling organisms on the membranes was statistically greater for the 28-d field exposure. The present study verified the high sensitivity and integrative nature of POCIS for relevant munitions constituents potentially present in aquatic environments, indicating that application at underwater military munitions sites may be useful for ecological risk assessment. Environ Toxicol Chem 2018;37:2257-2267. Published 2018 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Something fishy? Underwater munitions and unexplained die offs in marine environments

In November and December 2016, local residents around St. Mary’s Bay, Nova Scotia, Canada, noticed something alarming: thousands of dead fish were washing up along the coast. Scientists from the Canadian government’s Department of Fisheries and Oceans investigated, but the cause remains a mystery. This research note excogitates a potential cause: dumped chemical and conventional munitions. Between 1918 and 1972, most industrialized countries disposed of surplus munitions at sea. As a result, hundreds of millions of tons of corroded ordnance now pollute marine environments around the world. The article then discusses various research obstacles impeding further scholarly investigations and the possible connections between underwater munitions and the mass death of aquatic life.

Spread, Behavior, and Ecosystem Consequences of Conventional Munitions Compounds in Coastal Marine Waters

Coastal marine environments are contaminated globally with a vast quantity of unexploded ordnance and munitions from intentional disposal. These munitions contain organic explosive compounds as well as a variety of metals, and represent point sources of chemical pollution to marine waters. Most underwater munitions originate from World Wars at the beginning of the twentieth century, and metal munitions housings have been impacted by extensive corrosion over the course of the following decades. As a result, the risk of munitions-related contaminant release to the water column is increasing. The behavior of munitions compounds is well-characterized in terrestrial systems and groundwater, but is only poorly understood in marine systems. Organic explosive compounds, primarily nitroaromatics and nitramines, can be degraded or transformed by a variety of biotic and abiotic mechanisms. These reaction products exhibit a range in biogeochemical characteristics such as sorption by particles and sediments, and variable environmental behavior as a result. The reaction products often exhibit increased toxicity to biological receptors and geochemical controls like sorption can limit this exposure. Environmental samples typically show low concentrations of munitions compounds in water and sediments (on the order of ng/L and μg/kg, respectively), and ecological risk appears generally low. Nonetheless, recent work demonstrates the possibility of sub-lethal genetic and metabolic effects. This review evaluates the state of knowledge on the occurrence, fate, and effect of munition-related chemical contaminants in the marine environment. There remain a number of knowledge gaps that limit our understanding of munitions-related contaminant spread and effect, and the need for additional work is made all the more urgent by increasing risk of release to the environment.

Extracting elastic target information from acoustic scattering data of underwater munitions

Synthetic Aperture Sonar (SAS) acoustic scattering data from a variety of underwater munitions was collected in the Target and Reverberation Experiment 2013 (TREX13), Bay Experiment 2014 (BayEX14) and from the Acoustic Test Facility at Naval Surface Warfare Center Panama City Division. One data product from these tests is two dimensional templates of back scattered acoustic intensity as a function of aspect angle and frequency. A common method of target classification utilizes normalized template cross-correlations as the input into classification algorithms. This is typically done in a manner agnostic to observable physics-based scattering phenomena derived from the physical size, material composition, and geometry of the targets that might help improve classification performance. This presentation discusses methods explored to process the available data to make target elastic phenomena easier to recognize so that associated information can be extracted and used as target classifier input. The methods ex...

Technocratic Responses to the Politicization of Risk: Underwater Munitions in New York City’s Gravesend Bay and Narrows

Abstract Risk and its management are social phenomena, constructed through dynamic political, cultural, and economic systems. Those wishing to publicize and manage the risk posed by legacy underwater munitions would benefit from an awareness of the political context in which they work. The interaction of various local, national, and global political interests will enable certain kinds of risk management action while also constraining others. This article examines such issues through a case study of politics of underwater munitions in New York City’s Gravesend Bay and Narrows. The impetus to deal with these munitions has largely come from their politicization by local civilians: politicians, environmental activists, lawyers, and journalists. By contrast, risk management actions by national-level military institutions have consistently functioned to depoliticize the issue by framing it technocratically. This illustrates a common political tension in risk management. Public mobilization raises awareness of risk but may sensationalize it. Technocrats have the budgetary and technical wherewithal to deal with it professionally but resist politicization of risk and try to channel and defuse mobilization through existing institutions and programs.

Abrasive Waterjets—A Nontraditional Process for the Safe and Environmentally Friendly Demilitarization of Underwater High-Explosive Munitions

AbstractHigh-pressure abrasive waterjets provide a nontraditional tool for the safe and environmentally friendly demilitarization of high-explosive munitions, whether the munition is on land or underwater. High-pressure waterjets have cut and demilitarized over two million high-explosive items without incident, making it one of the safest and most environmentally friendly technologies for demilitarizing and recycling explosive munitions. This paper reviews the evolution of waterjet technology and discusses its applicability to underwater munitions.

Framework for Evaluating the Fate, Transport, and Risks From Conventional Munitions Compounds in Underwater Environments

AbstractLegacy underwater munitions may leak munitions constituents and, thereby, contaminate the environment and expose people to energetic compounds. This paper reviews the sources of underwater munitions, how munitions compounds are released, and their fate and transport characteristics. Because some of these energetic compounds and their environmental transformation products are toxic, we also describe the types of data needed to evaluate potential human and ecological risks at underwater munitions sites.

High-Resolution Imaging Sonar and Video Technologies for Detection and Classification of Underwater Munitions

AbstractThe detection of and response to underwater munitions will undoubtedly require the appropriate combinations of fully integrated sensors and imaging systems and platforms, as well as navigation and positioning technologies, to handle the variability in bottom conditions, water clarity and depth, size and type of munitions of interest, whether they are buried or proud. Where visibility allows, practically no sensing modality matches the details and information content from optical imaging systems for target localization, discrimination and identification. The significant disadvantage of optical systems for underwater applications is the range limitation. Sonar imaging systems are of limited resolution but do not have such a severe range limitation, as acoustic energy propagates well through turbid waters.In this study, we have explored two aspects of the munitions detection and classification process: (1) high-resolution mapping of an environment using a high-frequency sonar system to determine footprints of areas with munitions present and target localization in a wide-area survey and to perform detailed surveys for individual detected items during a re-acquisition process and (2) Multiple-Aspect Fixed-Range Template Matching (MAFR-TM) for detection and classification of the potential target.The MAFR-TM approach was tested using (1) a singular target scene collected in a test tank, (2) a cluttered scene acquired in the same test tank, and (3) a cluttered scene obtained in a realistic field environment (a marina). The munitions-like targets were cylinders made of steel or aluminum. The clutter was a collection of PVC tubes. Biological growth surrounded the target and artificial clutter in the marina. The experimental results indicate that the detection algorithm performs fairly well with the tank data (100% of the targets are detected) and cluttered tank data (94.44%). The classification between metals and plastics, proper orientation and target localization is also of good quality: 94.4% of the detected targets are properly classified as metal alloy if no clutter is present versus 82.35% in the presence of clutter. The algorithm performance in the marina is reasonably good, even though the overall performance drops: 61.11% of the targets are detected, and 68.18% of the detected targets are properly classified as metal alloy.

Exploiting multiple sensor modalities for classification of underwater munitions: A Dempster–Shafer theoretic approach

Detection and classification of underwater UXOs (UneXploded Ordnance) is a task that is receiving considerable attention from the DoD and related agencies that are involved in management of military munitions. Achieving a reasonable accuracy in detection and classification of these objects is extremely difficult mainly due to the harsh cluttered underwater environment. It is now an accepted fact that no single sensing technology can be both accurate and cost-effective. Low visibility in underwater exposes a significant limitation to optical cameras which are usually better suited for identifying the physical shape of objects. While acoustic imaging is a good alternative, the characteristics of imaging and physical system artifacts make the object recognition task non-trivial. Multi-sensory fusion provides an avenue to exploit the strengths of individual sensors and modalities while mitigating their weaknesses. We address the problem of fusion of multiple sensory information for the task of underwater UXO detection via the use of a Dempster–Shafer (DS) theoretic evidence fusion scheme. The DS theoretic foundation of our fusion algorithm also enables it to incorporate domain expert opinions and knowledge from databases to assist in the detection and classification tasks. We illustrate this method via the use of real data obtained at a test site located in the Florida Atlantic University premises.

Acoustic scattering from underwater munitions near a water-sediment interface.

Monostatic and bistatic scattering measurements were conducted on a set of targets near a fresh water-sand sediment interface. The measurements were performed during March 2010 and are referred to as the Pond Experiment 2010 (PondEx10). Monostatic synthetic aperture sonar (SAS) data were collected on a rail system with a mobile tower, while a stationary sonar tower simultaneously collected bistatic SAS data. Each tower is instrumented with receivers while the sources are located only on the mobile tower. For PondEx10, 11 targets, including 6 underwater munitions, were deployed at 2 ranges from the mobile tower system. Initially, the data were processed using standard SAS techniques, and then, the data were further processed to generate acoustic templates for the target strength as a function of frequency and aspect angle. Results of the data processing from proud targets are presented. Finite element model (FEM) predictions of the scattering from an ordnance in the free field and proud on the interface are also discussed. A processing technique that separates an individual target’s response from nearby targets is also briefly discussed. [Research supported by the SERDP and the ONR.]

An Overview of Underwater Technologies for Operations Involving Underwater Munitions

AbstractStudies to understand the potential risks associated with underwater munitions are still in their infancy. Response actions are normally driven by risk. From an explosives safety perspective, the Department of Defense believes leaving underwater munitions in place is often the safest course of action. Additionally, the risks posed by underwater munitions (e.g., sea disposal sites) remain largely unknown. Thus, it is unlikely that munition responses requiring the recovery of underwater munitions will occur in the near future. The exception is where such munitions are determined to pose an imminent and substantial threat to human health and the environment.This article discusses technologies that can be used to characterize underwater munition sites, including bounding the site and sampling for any release of munition constituents. It also addresses technologies that can be used for recovery operations and for the disposal of any munitions. Navigation and underwater positioning are integral to all of these operations and are discussed separately.

AUV Sensors for Real-Time Detection, Localization, Characterization, and Monitoring of Underwater Munitions

AbstractThis technical paper describes existing capabilities and new research results for autonomous underwater vehicles (AUVs) for use in locating, characterizing, and monitoring underwater munitions. The authors introduce advances in sensor technologies and search methods pertinent to AUV-based underwater munition mitigation operations. Results are presented from a series of trials using in situ chemical sensors to detect both conventional and nonconventional underwater munitions in real time. These technologies are considered within the context of chemical plume tracing and biomimetic search algorithms. This paper concludes with a look toward future AUV sensor payloads with more extensive real-time situation awareness. Advancement of these technologies and methods will be critical for realizing the potential of AUV platforms to manage the risks posed by underwater munitions sites.

A Global Prospective On Underwater Munitions

This article introduces an issue of the Marine Technology Society Journal focused on the understanding and ongoing exchange of information on underwater munitions. In June 2003, the Canadian Standing Senate Committee for Fisheries and Oceans on Fish Habitat listened to a panel of witnesses urgently request greater federal involvement from entities other than the Department of National Defense in addressing the issue of underwater munitions in both Canadian and international waters. When there was a lack of response from governments, as well as the United Nations, the First International Conference on Chemical and Conventional Munitions convened in Halifax, Nova Scotia, Canada in October 2007. Over 190 delegates from 14 countries affected by underwater munitions attended the conference and collectively submitted more than 50 papers. The author discusses the history of underwater munitions and explores relationships among international stakeholders which allow them to build on each others' experiences. The increasing awareness of and interest in identification and assessment of potential risks to human health and the environment by underwater munitions is explored.