Environmental impact of unexploded ordnance in the Baltic Sea

GEOMAR study detects toxic munitions chemicals in water samples

Helmholtz Centre for Ocean Research Kiel (GEOMAR)

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It is estimated that around 300,000 tonnes of unexploded ordnance (UXO) remain in the German Baltic Sea. Most of this originates from deliberate dumping after the end of the Second World War. These dumping sites are well documented, with much of the ordnance lying visibly on the seabed, allowing it to be mapped and documented using underwater robots. However, explosive compounds are spreading beyond these dumping sites. As corrosion progresses, contamination is expected to increase, heightening risks if these legacy munitions are not removed. Rising temperatures and increased storm activity due to climate change further accelerate the release of these explosive chemicals.

Toxins Found in Almost Every Sample

A new study from the GEOMAR Helmholtz Centre for Ocean Research Kiel highlights the long-term environmental contamination caused by unexploded ordnance in the south-western Baltic Sea. Water samples were taken from the region in 2017 and 2018, including from the Bay of Kiel and the Bay of Lübeck. Ammunition-related chemicals were detected in almost every water sample. The concentrations detected were generally well below drinking water limits or toxicological thresholds for marine organisms. In some cases, however, concentrations approached critical levels.

“Unexploded ordnance contains toxic substances such as TNT (2,4,6-trinitrotoluene), RDX (1,3,5-trinitro-1,3,5-triazine), and DNB (1,3-dinitrobenzene), which are released into the seawater when the metal casings corrode,” explains lead author Dr Aaron Beck, a geochemist at GEOMAR. “These compounds pose a threat to the marine environment and living organisms as they are toxic and carcinogenic.”

Regional Differences in Contamination

Due to variations in the types of munitions dumped, regional differences in contamination levels were observed: particularly high concentrations of TNT were measured in the Bay of Kiel, while RDX and DNB were more prevalent in the Bay of Lübeck. Most munitions-related chemicals were found in dissolved form rather than bound to suspended particles or sediments.

The researchers estimated that the current amount of dissolved munitions chemicals in the region is around 3,000 kilograms. Without removal action, the contamination is expected to increase as metal casings continue to corrode, releasing more and more toxic compounds. This process is projected to continue for at least 800 years.

A Global Environmental Issue

The study emphasises that chemical contamination from legacy munitions is an international problem. The researchers recommend that dumped ordnance be classified as “historical contaminants of emerging concern” and addressing them through targeted remediation efforts.

Aaron Beck states: “Unlike diffuse pollution sources, UXO exists in a concentrated, already packaged form. This means it can be physically removed from the environment.” Germany’s munitions clearance operations could serve as a model for the removal of such hazardous waste around the world. “With war relics, at least one environmental stressor can be permanently eliminated from the marine ecosystem.”

 

About: Munitions Clearance Pilot Project

The German government launched a pilot programme for the recovery and environmentally sound disposal of legacy munitions. With a budget of 100 million euros, this was the first targeted effort worldwide to remove munitions remnants from the Sea. The pilot clearance operation began in autumn 2024 in the Bay of Lübeck. The next step is to use the data collected to develop an autonomous clearance platform that will treat and incinerate the ordnance at sea.

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Journal

Chemosphere

DOI

10.1016/j.chemosphere.2025.144115 

Method of Research

Observational study

Article Title

Widespread environmental contamination from relic munitions in the southwestern Baltic Sea

 

Recycling your bulletproof vest in a microwave reactor

University of Groningen

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This is an artistic representation of the depolymerization of aramid fibres

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Credit: Dr. Dina Maniar, University of Groningen

Twaron and Kevlar are brand names for aramid fibres, which are strong as steel yet much lighter. They are used to make bulletproof vests, strong ropes, and high-performance car tires, for example. These extremely tough materials have one drawback: they are very difficult to recycle. Polymer scientists at the University of Groningen and NHL Stenden University of Applied Sciences (the Netherlands), in cooperation with the Dutch company Teijin Aramid, have developed a novel microwave-assisted chemical recycling process for aramid fibres, as described in a publication in the Journal of the American Chemical Society on 21 February.

Organic solvent

Aramid is made from PPTA, short for poly(p-phenylene terephthalamide). Current recycling techniques include mechanical and chemical recycling. But the mechanical recycling of Aramid results in a lower quality material, and although chemical recycling can break down the polymer into monomers, current methods require the use of organic solvents for several hours at high temperature and pressure.

The new technique uses a microwave reactor, which accelerates depolymerization at lower temperatures, and requires no organic solvents. The process has a conversion rate of 96% in 15 minutes.

Sustainable material management

‘Given the $2.9 billion aramid fibres market, this process could contribute to more sustainable material management and support closed-circle recycling initiatives in the industry,’ says Katja Loos, Professor of Macromolecular Chemistry and corresponding author of the JACS paper. In order to better understand and improve the depolymerization process, more research needs to be done in collaboration with Teijin Aramid.

This research is sponsored by the Closing Carbon Cycles with Renewable Amines (3CRA) programme of the Netherlands Enterprise Agency, and was conducted within the hybrid research group "Biopolymers and Recycling Innovation" (HyBRit). HyBRit is a collaboration between the University of Groningen and NHL Stenden.

Reference: Joël Benninga, Bert Gebben, Rudy Folkersma, Vincent S.D. Voet en Katja Loos: Rapid Microwave-Assisted Chemical Recycling of Poly(p-Phenylene Terephthalamide). JACS 21 februari 2025

This is  Joël Banninga, first author of the JACS paper describing efficient chemical recycling of aramid fibers.

Credit

University of Groningen

Graphical abstract of the paper describing efficient chemical recycling of aramid fibers.

Credit

University of Groningen / JACS

Journal

Journal of the American Chemical Society

DOI

10.1021/jacs.4c17791 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Rapid Microwave-Assisted Chemical Recycling of Poly(p-Phenylene Terephthalamide)

Article Publication Date

26-Feb-2025

 

AI generates playful, human-like games

Researchers develop computer model to understand and generate human-like goals

Peer-Reviewed Publication

New York University

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While we are remarkably capable of generating our own goals, beginning with child’s play and continuing into adulthood, we don’t yet have computer models for understanding this human ability. 

However, a team of New York University scientists has now created a computer model that can represent and generate human-like goals by learning from how people create games. The work, reported in the journal Nature Machine Intelligence, could lead to AI systems that better understand human intentions and more faithfully model and align with our goals. It may also lead to AI systems that can help us design more human-like games.

“While goals are fundamental to human behavior, we know very little about how people represent and come up with them—and lack models that capture the richness and creativity of human-generated goals,” explains Guy Davidson, the paper’s lead author and an NYU doctoral student. “Our research provides a new framework for understanding how people create and represent goals, which could help develop more creative, original, and effective AI systems.”

Despite considerable experimental and computational work on goals and goal-oriented behavior, AI models are still far from capturing the richness of everyday human goals. To address this gap, the paper’s authors studied how humans create their own goals, or tasks, in order to potentially illuminate how both are generated. 

The researchers began by capturing how humans describe goal-setting actions through a series of online experiments. 

They placed participants in a virtual room that contained several objects. The participants were asked to imagine and propose a wide range of playful goals, or games, linked to the room’s contents—e.g., bouncing a ball into a bin by first throwing it off a wall or stacking games involving building towers from wooden blocks. The researchers recorded the participants’ descriptions of these goals linked to the devised games—nearly 100 games in total. These descriptions formed a dataset of games from which the researchers’ model learned.  

While human-goal generation may seem limitless, the goals study participants created were guided by a finite number of simple principles of both common sense (goals must be physically plausible) and recombination (new goals are created from shared gameplay elements). For instance, participants created rules in which a ball could realistically be thrown in a bin or bounced off a wall (plausibility) and combined basic throwing elements to create various games (off the wall, onto the bed, throwing from the desk, with or without knocking blocks over, etc., as examples of recombination).

The researchers then trained the AI model to create goal-oriented games using the rules and objectives developed by the human participants. To determine if these AI-created goals aligned with those created by humans, the researchers asked a new group of participants to rate games along several attributes, such as fun, creativity, and difficulty. Participants rated both human-generated and AI-produced games, as in the example below:

Human-created game:

• Gameplay: throw a ball so that it touches a wall and then either catch it or touch it 

• Scoring: you get 1 point for each time you successfully throw the ball, it touches a wall, and you are either holding it again or touching it after its flight

AI-created game:

• Gameplay: throw dodgeballs so that they land and come to rest on the top shelf; the game ends after 30 seconds

• Scoring: you get 1 point for each dodgeball that is resting on the top shelf at the end of the game

Overall, the human participants gave similar ratings to human-created games and those generated by the AI model. These results indicate that the model successfully captured the ways humans develop new goals and generated its own playful goals that were indistinguishable from human-created ones.

This research helps further our understanding of how we form goals, and how these goals can be represented to computers. It can also help us create systems that aid in designing games and other playful activities.

The paper’s other authors are Graham Todd, an NYU doctoral student, Julian Togelius, an associate professor at NYU’s Tandon School of Engineering, Todd M. Gureckis, a professor in NYU’s Department of Psychology, and Brenden M. Lake, an associate professor in NYU’s Center for Data Science and Department of Psychology.

The research was supported by grants from the National Science Foundation (1922658, BCS 2121102).

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Journal

Nature Machine Intelligence

DOI

10.1038/s42256-025-00981-4 

Method of Research

Experimental study

Article Title

Goals as reward-producing programs

Article Publication Date

26-Feb-2025

 

Time interfaces: The gateway to four-dimensional quantum optics

University of Eastern Finland

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A new study from the University of Eastern Finland (UEF) explores the behavior of photons, the elementary particles of light, as they encounter boundaries where material properties change rapidly over time. This research uncovers remarkable quantum optical phenomena which may enhance quantum technology and paves the road for an exciting nascent field: four-dimensional quantum optics.

Four-dimensional optics is a research area investigating light scattering from structures which change in time and space. It holds immense promise for advancing microwave and optical technologies by enabling functionalities such as frequency conversion, amplification, polarization engineering and asymmetric scattering. That is why it has captured the interest of many researchers across the globe.

Previous years have seen significant strides in this area. For instance, a recent international study published in Nature Photonics and also involving UEF highlights how incorporating optical features like resonances can drastically influence the interaction of electromagnetic fields with time-varying two-dimensional structures, opening exotic possibilities to control light.

Now, building on their previous works in classical optics, the researchers at UEF have extended their investigation to quantum optics. The team has conducted a detailed investigation into quantum light interaction with a material whose macroscopic property changes abruptly in time, creating a single temporal interface between two different media (like the interface between air and water, but in time rather than in space).

Dr Mirmoosa, the lead researcher in this study, explains: “Four-dimensional quantum optics is the next logical step, allowing us to explore the implications of this area for quantum technology. Our research has taken this initial step and now provides a foundational tool for us to examine complex structures, changing in time and space, for uncovering novel quantum optical effects.”

The investigation showed and revealed several intriguing phenomena, including photon-pair creation and annihilation, vacuum state generation and quantum state freezing, all of which may have potential applications in quantum technology.

The researchers acknowledge that this is just the beginning. Four-dimensional quantum optics becomes an emerging field poised to attract significant attention in the near future. For instance, exploring how quantum light fields interact with periodically repeating time interfaces, known as photonic time crystals, is particularly exciting.

Dr Mirmoosa adds: “In our paper, we did not take into account dispersion. Real materials are nonetheless dispersive in nature, meaning that responses have a delay relative to the excitations. To address such an intrinsic feature necessitates the development of a more comprehensive theory.”
He continues: “Incorporating dispersion may lead to new possibilities for controlling the quantum states of light, and I am very motivated to explore that.”

The study was published recently in Physical Review Research.

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Journal

Physical Review Research

DOI

10.1103/PhysRevResearch.7.013120 

Article Title

Quantum state engineering and photon statistics at electromagnetic time interfaces.

 

Novel photochromic glass can store rewritable 3D patterns

American Chemical Society

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A tiny cube of transparent glass holds these 3D designs that are revealed when exposed to specific lasers.

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Credit: Adapted from ACS Energy Letters 2025, DOI: 10.1021/acsenergylett.5c00024

For decades researchers have been exploring how to store data in glass because of its potential to hold information for a long time — eons — without applying power. A special type of glass that changes color in different wavelengths of light, called photochromic glass, holds promise for stable, reusable data storage. Now, researchers have developed a doped photochromic glass that has the potential to store rewritable data indefinitely, according to research published in ACS Energy Letters.

Certain types of eyeglasses get darker when exposed to wavelengths of light emitted by the sun and then shift back to a colorless lens indoors when no longer exposed to those light waves through a process called reversible photochromism. Likewise, other types of photochromic glass can switch color in response to different wavelengths of light, making this material attractive as an inexpensive and stable platform for storing vast amounts of information in a small space. But the challenge in using photochromic glass for data storage involves not only writing information into the glass but also erasing and rewriting it ad infinitum. Now, Jiayan Liao, Ji Zhou, Zhengwen Yang and a multidisciplinary team have made progress toward this goal by creating reversible, tunable patterns on photochromic gallium silicate glass.

The team first designed gallium silicate glass modified with magnesium and terbium ions by using a process called doped direct 3D lithography. Liao and the team used a green 532-nanometer (nm)-wavelength laser to inscribe 3D patterns into tiny slabs of the doped glass. The intricate patterns, randomly chosen dots, symbols, QR codes, geometric prisms, and even a bird, appear purple in the transparent glass, which turns other colors when excited at precise wavelengths. Terbium luminesces green when excited by a deep violet 376-nm laser, and magnesium luminesces red in the presence of violet light at 417 nm. Then, to fully erase the patterns without changing the structure of the glass, the team applied heat at 1022 degrees Fahrenheit (550 degrees Celsius) for 25 minutes.

Furthermore, the researchers consider the use of magnesium and terbium groundbreaking for their abilities to luminesce at distinctly different wavelengths, which makes it possible to get a tunable, multicolor readout of 3D patterns from a single material. The new approach could be used for high-capacity, stable 3D optical memory storage and encryption in industrial, academic and military applications.

The authors acknowledge financial support from the National Natural Science Foundation of China, Science and Technology Project of Southwest Joint Graduate School of Yunnan Province, Key Project of the National Natural Science Foundation of China-Yunnan Joint Fund, National Natural Science Foundation of High-end Foreign Experts Introduction Plan, Academician Expert Workstation of Cherkasova Tatiana in Yunnan Province, Yunnan Province Major Science and Technology Special Plan, Preparation and Property Control of Luminescent Materials and Application in Plateau Agriculture, University of Technology Sydney Chancellor’s Research Fellowship Program, and the National Health and Medical Research Council.

The paper’s abstract will be available on Feb. 26 at 8 a.m. Eastern time here: http://pubs.acs.org/doi/abs/10.1021/acsenergylett.5c00024    

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A new type of glass that’s etched with a bird design appears differently when exposed to different lasers.

Credit

Adapted from ACS Energy Letters 2025, DOI: 10.1021/acsenergylett.5c00024

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Journal

ACS Energy Letters

DOI

10.1021/acsenergylett.5c00024 

Article Title

Direct 3D Lithography of Reversible Photochromic Patterns with Tunable Luminescence in Amorphous Transparent Media

Article Publication Date

26-Feb-2025