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

Abstract

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.

Release of Munitions Constituents in Aquatic Environments Under Realistic Scenarios and Validation of Polar Organic Chemical Integrative Samplers for Monitoring

“…However, maximum RDX and TNT concentrations in the flume water were lower than these highest attainable levels, consistent with the observation of low loss of Composition B mass at experiment termination (see Composition B fragments mass loss section). Therefore, the low maximum average concentration observed is not related to saturation because the maximum attainable dissolved concentrations in the flume and in the aforementioned aquaria experiments are significantly lower than the solubility limits for RDX and TNT (Beck et al ). Although a determination of why increasing concentrations tend to plateau is outside the scope of the present study, our hypothesis is that the observed behavior is likely related to decreases in the availability of water‐accessible MC at the Composition B surface.…”

“…Underwater sites around the world are known to contain underwater military munitions (UWMM) as a result of military activities or historic disposal events. Munitions constituents (MC) including 2,4,6‐trinitrotoluene (TNT) and 1,3,5‐trinitro‐1,3,5‐triazine (RDX) may be released into the surrounding aquatic environments as a result of UWMM corrosion and breaching of the munition's outer casing (Lewis et al ; Rosen and Lotufo ; Wang et al ; Li et al ; Voie and Mariussen ; Rosen et al ; Beck et al ). Release may also occur from fragments of explosives formulations that become exposed following low‐order (incomplete) detonations resulting in fully breached munitions (Beck et al ).…”

13C and 15N NMR identification of product compound classes from aqueous and solid phase photodegradation of 2,4,6-trinitrotoluene

“…The major transformation pathways of 2,4,6-trinitrotoluene (TNT) released into the environment include microbial reduction, metal catalyzed abiotic reduction, and photolysis, depending on the individual soil, sediment, or aquatic matrix [1–15]. TNT is also susceptible to alkaline hydrolysis, but the conditions of pH ≥ 9 required for significant hydrolysis to occur are not relevant to most environments.…”

“…Where TNT reaches the photic zone in surface waters or where light intensity is adequate, it may be assumed that photolysis takes place. Studies have detected TNT in surrounding sediments or in the water column derived from underwater unexploded ordnance [1, 12, 29–32].…”

Contribution of Remote Sensing Technologies to a Holistic Coastal and Marine Environmental Management Framework: A Review

“…Furthermore, another issue resulting from military activities in coastal marine environments is the intentional disposal of unexploded ordnance and munitions that contain organic explosives and a variety of metals. These can be assessed by RS technologies (USV and UUV) using Multibeam sonar, sub-bottom profiling, and magnetometry [132].…”