Mark Ballentine

• PhD Oceanography
• Researcher at U.S. Army Engineer Research and Development Center

Gas sensors are critical in detecting various gases across industrial, environmental, and healthcare applications. Among them, electrochemical gas sensors stand out due to their high sensitivity, selectivity, and portability. However, traditional electrochemical gas sensors have faced limitations regarding long-term stability and the ability to det...

The purpose of this technical note is to disseminate methods to design and create a 3D device that could be used to determine relative toxicity potential of existing and emerging contaminants of concern in situ for sediment shoaled in federal navigation channels prior to being dredged. This device has the potential to reduce the cost of conventiona...

Nanomaterials are used in polymer composites to enhance plastic products’ properties. Silver nanoparticles (AgNPs) are added to composites for their antimicrobial and fungicidal properties. Polyethylene terephthalate glycol polymer (PETG) AgNP...

The accessibility and popularity of additive manufacturing (AM) has increased over the past decade. Environmental hazard assessment and safety data sheets for 3D printer feedstocks has lagged technology development. Vat photopolymerization may have unique risks relative to other AM technologies due to mishandling of uncured monomers/oligomer feedst...

Novel and sustainable solutions are needed for surface water treatment. Photocatalytic TiO2 is studied but is not directly deployable into natural water bodies due to settling and poor recoverability. This research capitalizes on a convergence of the emerging technologies of 3D printing biocompatible polymer (polylactic acid, PLA) composites, nanot...

Per- and polyfluoroalkyl substances (PFAS) are a complex group of recalcitrant substances that are present globally in many landfill wastewater leachates and have potential ecological and human health risks. Conventional treatment technologies have shown limited efficacy for many PFAS due to the stable C–F bonds. Therefore, there is growing interes...

It is critical to thoroughly investigate, characterize, and understand the unique emission profiles of common and novel polymer feedstocks used in fused filament fabrication (FFF) 3D printers as these products become increasingly ubiquitous in consumer and industrial environments. This work contributes unique insights regarding the effects of polym...

Evaluations of field sites containing multiple contaminants are commonly impacted by ammonia from anthropogenic and natural sources. Scientifically defensible lines of evidence regarding which contaminants cause toxicity inform management decisions. Methods are needed to isolate ammonia toxicity from other contaminant effects without the treatment...

The impacts of Harmful Algal Blooms (HAB), often caused by cyanobacteria (Figure 1), on water resources are increasing. Innovative solutions for treatment of HABs and their associated toxins are needed to mitigate these impacts and decrease risks without introducing persistent legacy contaminants that cause collateral ecosystem impacts. This techni...

Recent progress in developing composites embedded with photocatalysts indicates application for wastewater treatment. However, significant gaps remain in developing effective photocatalyst–polymer composites for use as customizable, deployable, and retrievable structures for mitigating environmental contamination. The goal of this study was to gene...

Fused filament fabrication (FFF) 3D printers are increasingly used in industrial, academic, military, and residential sectors, yet their emissions and associated user exposure scenarios are not fully described. Characterization of potential user exposure and environmental releases requires robust investigation. During operation, common FFF 3D print...

The Army is replacing traditional munitions with insensitive munitions (IM) resistant to accidental detonation. The aquatic toxicity of 1-methyl-3-nitroguanidine (MeNQ), which is being assessed for potential use in IM formulations, remains largely untested. The present study fills a number of critical data gaps for MeNQ aquatic toxicity by evaluati...

This Dredging Operations Environmental Research (DOER) technical note disseminates novel methods to monitor and reduce contaminant mobility and bioavailability in water, sediments, and soils. These method advancements are enabled by additive manufacturing (i.e., three-dimensional [3D] printing) to deploy and retrieve materials that adsorb contamina...

Use of three-dimensional (3D) printing in industrial and residential settings has grown exponentially with the development of less expensive equipment. However, understanding of particle emissions from these machines is limited, particularly when additives are integrated into the printable filament feedstocks. In this work, we assessed emissions fr...

The diverse suite of contaminants released to the environment requires creative solutions. This research identifies novel application of additive manufacturing to rapidly prototype functional composite structures to adsorb contaminants. Ammonia contamination of water from natural and anthropogenic sources is common. Granular zeolite removes ammonia...

Natural communities of microbes inhabiting amphibian skin, the skin microbiome, are critical to supporting amphibian health and disease resistance. To enable the pro-active health assessment and management of amphibians on Army installations and beyond, we investigated the effects of acute (96h) munitions exposures to Rana pipiens (leopard frog) ta...

Hundreds of explosive-contaminated marine sites exist globally, many of which contain the common munitions constituent hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Quantitative information about RDX transformation in coastal ecosystems is essential for management of many of these sites. Isotopically labelled RDX containing ¹⁵N in all 3 nitro grou...

The Army is replacing traditional munitions with insensitive munitions (IM) resistant to accidental detonation. Although the parent IM compound nitroguanidine (NQ) is generally not acutely toxic at concentrations >1000 mg/L in aquatic exposures, products formed by intensive UV‐degradation resulted in multiple‐order of magnitude increase in toxicity...

Tracing the cycling and fate of the munition, Hexahydro-1,3,5-trinitro-1,3,5-triazine in a simulated sandy coastal marine habitat with a stable isotopic tracer, 15 N-[RDX]

This Technical Report (TR) extends on the ERDC NanoGRID (Nanomaterials Guidance for Risk Informed Deployment) program and considers methods needed to assess material released from composites made with manufactured nanomaterials (MN). Specifically this TR builds from the measurement literature on multi-walled carbon nanotubes released from a matrix...

Coastal marine habitats become contaminated with the munitions constituent, Hexahydro-1,3,5-trinitro-1,3,5-trazine (RDX), via military training, weapon testing and leakage of unexploded ordnance. This study used 15N labeled RDX in simulated aquarium-scale coastal marine habitat containing seawater, sediment, and biota to track removal pathways from...

Underwater military munitions (UWMM) may pose a risk to aquatic environments because they typically contain munitions constituents (MC) such as 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). If UWMM become corroded or breaches, the fill material may leak or dissolve into the surrounding environment, which could poten...

2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5 (RDX) have been used extensively by the world’s militaries for more than a century. Millions of tons of these compounds have been released into marine environments globally. Contamination levels and biological accumulation of TNT and RDX in marine systems from both legacy and new enviro...

2,4,6-trinitrotoluene (TNT) has been used as a military explosive for over a hundred years. Contamination concerns have arisen as a result of manufacturing and use on a large scale; however, despite decades of work addressing TNT contamination in the environment, its fate in marine ecosystems is not fully resolved. Here we examine the cycling and f...

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a common constituent of military explosives. Despite widespread RDX contamination at U.S. military facilities and its mobility to aquatic systems, the fate of RDX in marine systems remains largely unknown. Here, we provide RDX mineralization pathways and rates in seawater and sediments, highlighting...

The bioconcentration factor (BCF) was measured for 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in seven different marine species of varying trophic levels. Time series and concentration gradient treatments were used for water column and tissue concentrations of TNT, RDX, and their environmentally important derivati...

In the above article, calculated ‘k’ rates and half-lives were correct in the graphs but were incorrectly transposed to Table 1. Here, the correct table is given along with corrected text that referenced the incorrect values in the table. Conclusions drawn in the manuscript were based on the correct values, and therefore stand.

Vitamin D signaling modulates a variety of immune responses. Here, we assessed the role of vitamin D in immunity to experimental leishmaniasis infection in vitamin D receptor-deficient mice (VDRKO). We observed that VDRKO mice on a genetically resistant background have decreased Leishmania major-induced lesion development compared to wild-type (WT)...

VDRKO mice have increased numbers of T-cells in the draining lymph nodes; restimulation of lymph nodes; nitric oxide and IL-12p40 by macrophages from WT and VDRKO mice.