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

Aaron J Beck,Martha Gledhill,Eric P Achterberg,Jens Greinert,Claus Böttcher,Christian Schlosser,Jens Sternheim,Beate Stamer

doi:10.3389/fmars.2018.00141

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.

Highlights

Coastal marine environments are contaminated globally with unexploded ordnance and munitions from intentional disposal (Figure 1), but their distribution and condition are not well known (Sanderson et al, 2017)
We focus on the chemical constituents that typically occur in conventional munitions present in the marine environment
The purpose of the current review is to evaluate the state of knowledge on the occurrence, fate, and effect of munitionrelated chemical contaminants in the marine environment

Summary

Introduction

Coastal marine environments are contaminated globally with unexploded ordnance and munitions from intentional disposal (Figure 1), but their distribution and condition are not well known (Sanderson et al, 2017). We focus on the chemical constituents that typically occur in conventional munitions present in the marine environment. This includes organic explosive compounds, metalloorganic explosives, and metals used in casings and housings of munitions. Some more sensitive metaloorganic compounds used as initiators for detonation of secondary explosives will be discussed (e.g., fulminates, azides, and styphnates of mercury, lead, and silver), their marine environmental behavior and fate is very poorly known. There are other explosive compounds used historically (e.g., tetryl and ammonium picrate), or which are more recently developed (e.g., hexanitrohexaazaisowurtzitane), but TNT, RDX, and HMX represent a major portion of munition material present in terrestrial and marine environments (US EPA, 2012)

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