The study, published in Frontiers in Geochemistry, examined mine wastes from two strikingly different legacy mining regions: the town of Cobalt in Ontario, Canada, and three historic mine sites in Cornwall, England. Despite vast differences in geology, ore type, and processing methods spanning a millennium of mining history, the researchers found that cobalt in both locations showed consistently high potential for mobilization — meaning it could readily dissolve and travel into aquatic environments where it might enter the food chain.

“The concentrations we found at Cobalt, Canada were extraordinary,” the research indicates, with high-grade Nipissing tailings containing up to 5,630 milligrams of cobalt per kilogram of material — roughly 900 times higher than the Cornwall sites. Even the low-grade tailings at Cobalt reached 1,230 milligrams per kilogram, dwarfing the averages of 40, 76, and 59 milligrams per kilogram found at Poldice, Wheal Unity, and Dolcoath mines in Cornwall respectively. These concentrations far exceed residential soil quality guidelines set by regulatory bodies in Ontario, Canada, the United States, and the European Union.

The research team, led by Gabriel Ziwa of the Camborne School of Mines at the University of Exeter, employed a sophisticated battery of analytical techniques to understand not just how much cobalt was present, but in what chemical forms. Using X-ray diffraction, scanning electron microscopy, and electron microprobe analysis, they identified the specific minerals hosting the cobalt — a crucial step because a metal locked inside a stable crystal is far less dangerous than one sitting on a mineral surface ready to dissolve at the first change in water chemistry.

At Cobalt, Canada, the picture was dominated by a striking pink mineral called erythrite — a cobalt arsenate that formed as needle-like crystals growing on silicate and carbonate grains throughout the tailings. This secondary mineral, containing roughly 20.8 percent cobalt by weight, proved to be the most widespread cobalt-bearing phase at the site. The researchers also identified primary cobalt minerals including cobaltite, safflorite, and skutterudite, alongside cobalt incorporated into arsenopyrite, loellingite, pyrite, and chalcopyrite. Secondary phases such as arseniosiderite, scorodite, and iron oxyhydroxides also harboured significant cobalt concentrations.

In Cornwall, by contrast, no dedicated cobalt minerals were found at all. Instead, cobalt existed only as a trace component — typically less than one percent by weight — hidden inside common sulfide minerals like pyrite, chalcopyrite, and arsenopyrite, and in secondary phases such as scorodite and iron-manganese oxyhydroxides. Yet this difference in mineralogical hosting made almost no difference to the metal’s behaviour when subjected to sequential extraction testing.

The most alarming result came from the BCR sequential extraction analysis, a standardized European protocol that subjects mine waste to progressively stronger chemical leaches to simulate what might happen under different environmental conditions. In both the Canadian and British samples, an average of 46 percent of the total cobalt was extracted in the very first, mildest step — the “exchangeable” fraction that represents metal most easily dissolved by slight changes in acidity. This means nearly half the cobalt in these wastes is sitting in a form that could be released into water with only minor pH shifts.

Applying the Risk Assessment Code framework developed by Perin and colleagues, the researchers classified cobalt in the Cornwall samples as ranging from high risk to very high risk, with individual samples reaching exchangeable fractions of up to 62 percent. At Cobalt, Canada, values ranged from 28 to 58 percent, placing the metal in medium to very high risk categories. According to the RAC guidelines, metals exceeding 50 percent in the exchangeable fraction are considered to easily enter the food chain — a classification that directly implicates these mine wastes as potential vectors for human cobalt exposure through crops, livestock, and water supplies.

The chemistry behind this mobilization is well understood. At Cornwall’s acidic sites, where paste pH values ranged from 3.72 to 5.77, sulfide minerals like pyrite generate acid through oxidation, and any cobalt-bearing phases dissolve readily, releasing cobalt ions and arsenic oxyanions into solution. At Cobalt, Canada, the near-neutral pH of 7.50 to 7.84 currently stabilizes erythrite within its thermodynamic stability field — but the researchers warn this equilibrium is fragile. A shift toward acidity, whether from changing oxidation conditions or altered hydrology, could dissolve the erythrite and release its cobalt payload. The iron and manganese oxyhydroxides that scavenge cobalt in both locations are themselves thermodynamically unstable under reducing conditions, meaning buried or waterlogged wastes could also release their stored metal.

What makes this research particularly significant is its implication for the future. Cobalt demand is projected to surge as electric vehicle adoption accelerates globally, and governments worldwide have designated it a strategic resource. Yet the environmental behaviour of cobalt in mine waste has been remarkably understudied compared to metals like arsenic or lead. The Exeter team’s finding that cobalt behaves similarly across such geologically different settings — a five-element silver-cobalt-nickel vein deposit in Precambrian rocks versus polymetallic tin-copper-arsenic veins in Devonian-Carboniferous host rocks — suggests that the metal’s mobility in mine waste may follow predictable patterns worldwide. If confirmed by further research, this would mean that every new cobalt mine opening today is generating waste with the same latent capacity to contaminate water and food chains that century-old sites in Canada and England are only now revealing.

Subject of Research: Geochemistry and mineralogy of cobalt mobility in legacy mine wastes from Cobalt, Canada and Cornwall, England

Article Title: Geochemistry and mineralogy of Cobalt in mine wastes: examples from Cobalt, Canada and Cornwall, England

Article References: Ziwa, G., Crane, R., & Hudson-Edwards, K. A. (2025). Geochemistry and mineralogy of Cobalt in mine wastes: examples from Cobalt, Canada and Cornwall, England. Frontiers in Geochemistry, 3, Article 1543695. https://doi.org/10.3389/fgeoc.2025.1543695

Image Credits: AI Generated

DOI: 10.3389/fgeoc.2025.1543695

Keywords: cobalt, mine waste, tailings, geochemistry, mineralogy, erythrite, sequential extraction, mobility, critical raw materials, contamination, Cornwall, Ontario

Modern geologists now understand the Lizard as an obducted ophiolite, a fragment of oceanic crust and underlying mantle rocks thrust onto the southern margin of the continent of Avalonia during the Variscan orogeny, as the Rheic Ocean closed in the early Paleozoic era. The tectonostratigraphy is remarkably complete: sheeted dykes sit atop the crustal Crousa gabbro, which is underlain by a highly sheared Moho transition zone and the Traboe cumulate complex, all resting above a mantle sequence of serpentinized lherzolite, harzburgite, and dunite peridotites. The entire sequence was thrust over a metamorphic sole, including the Landewednack amphibolite, and a complex mélange containing fragments of the Man of War Gneiss and the Mullion Island pillow lavas. Yet when the first geologists arrived in the early nineteenth century, none of this framework existed. There was no understanding of the distinction between oceanic and continental lithosphere, no theory of plate tectonics, and no coherent way to interpret the region’s complexly faulted and metamorphosed rocks.

The earliest significant survey was conducted in 1818 by Ashurst Majendie, a founding member of the Geological Society of London, who set out to map the boundaries and position of the serpentine formation around the Lizard Promontory. Working along the coast from Loe-Bar to the Helford estuary, Majendie recognized the contacts between what are now known as the Old Lizard Head Series, the Landewednack amphibolite, the serpentinized peridotite, and the Crousa gabbro, producing the first geological map of the region. Given the uniqueness of the rocks, the structural complexity of the peninsula, and the primitive analytical techniques of the day, his map is remarkably congruent with modern surveys in the positions of its major lithologic boundaries, even though the nature of the contacts and the ages of the rock bodies remained beyond his grasp.

In the summer of 1819, Adam Sedgwick, recently appointed Woodwardian Professor of geology at Cambridge, toured Cornwall in the company of the Reverend William R. Gilby, publishing his results in 1822. Sedgwick was drawn to the region because it differed so essentially from every other part of Cornwall, and he hoped to convey a correct notion of the great mineral masses that successively presented themselves along the coast. Tracing the cliffs clockwise from the Helford estuary to Mullion Cove, Sedgwick encountered the serpentine that stretches six or eight miles from coast to coast and occupies about one-third of the peninsula. He was repeatedly confounded by the poorly defined contacts between lithologies, noting that rocks at the junctions of formations were often in an advanced stage of decomposition. At Kennack Cove he struggled to describe the rapid alternation of mineral aggregates that seemed to mutually penetrate one another, and near Karak Clews he was surprised to find rocks suddenly cut off by the reappearance of serpentine, wedged between nearly perpendicular faces of the altered peridotite.

Sedgwick also left vivid descriptions of the region’s celebrated geomorphic features, including the Devil’s Frying Pan below the village of Cadgwith, which he called a magnificent natural amphitheater formed by the decomposition of serpentine, with a natural bridge of the same rock spanning the gulf where the sea had forced a passage into the chasm. Modern mapping shows that outcrops of the Lizard Peridotite, the Landewednack Amphibolite, and the Kennack Granite all occur within the circumference of that depression, details that Sedgwick suggested but could not fully resolve. He ultimately concluded that the great plateau of the Lizard was not composed of stratified rocks, and that the serpentine belonged to the class of transitional rather than primitive rocks within the classification system of his era. Notably, he and Gilby also recorded white quartz pebbles in the alluvium capping the downs north of Coverack, deposits now understood to be the Neogene Crousa gravels, though few nineteenth-century geologists considered their origin.

Subsequent workers built incrementally on these foundations. In 1822 the Reverend John Rogers read a paper to the Royal Geological Society of Cornwall, arguing that an accurate knowledge of so complex a district could only be attained by repeated examination, though his brief study of the eastern coast added relatively little beyond the four-fold division of the rocks into Devonian clay slates, amphibolite schist, gabbro, and serpentine. In 1839 Henry T. De la Beche, the first director of the Ordnance Geological Survey, published a nearly seven-hundred-page report on the geology of southwest England. Within it he recognized that the mica slates of the Lizard were of very different character from the great schistose systems of Cornwall and Devon, distinguishing the Old Lizard Head Series from the Devonian schists to the north. He also proposed that the hornblende slate had formed a basin into which the serpentine and gabbro had been poured in a state of fusion, an interpretation that was clearly incorrect but understandable given the synclinal geometry of the western coast and the difficulty of recognizing the region’s pervasive faulting.

By the 1870s, attention had shifted to the microscopic world. In 1876, professors William King and Thomas H. Rowney of Queens College Galway analyzed the Lizard serpentinite to counter the claim that serpentine was an original chemical precipitate, concluding instead that it was the product of chemical changes, which they termed methylosis, effected in a preexisting rock near the surface of the earth. King and Rowney were seasoned controversialists, having correctly identified the famous pseudofossil Eozoön canadense as interlayered calcite and serpentine of abiotic origin, and King was also celebrated for recognizing the Neanderthal as a species distinct from modern humans. Their study produced one of the most striking illustrations in nineteenth-century geology, a surrealistic composite of twenty-two distinct microscopical features, and they reviewed a series of ovoid and branching textures in the Lizard serpentine, finding them to be mineralogical rather than organic in origin.

The decisive breakthrough came from the Reverend Thomas G. Bonney of St. John’s College, Cambridge, who read the first large-scale petrographic study of the Lizard to the Geological Society of London in May 1877. Armed with the polarizing microscope, Bonney combined extensive coastal fieldwork with detailed examination of thin sections, hoping to explain phenomena with which the appliances of earlier workers could not deal. He recognized five distinct lithologies and worked out temporal relationships among them, concluding that the serpentine was originally an igneous rock formed after the metamorphism of the amphibolite, that serpentinization was complete before later intrusions, and that the dark trap dykes were the youngest rocks of the peninsula. His microscopic examinations of serpentine from fourteen locations led him to the conclusion that the Lizard serpentine was an altered olivine rock, comparing a specimen from Coverack Cove with lherzolite he collected from the type locality at Etang de Lherz in the French Pyrenees. He attributed serpentinization to the gradual decomposition of olivine by slowly infiltrated water, an interpretation broadly aligned with the methylosis concept of King and Rowney, though modern science now understands the process as a moderate to high temperature metamorphic reaction of forsterite with water and excess silica to form the serpentine mineral lizardite.

Bonney returned to the Lizard in the spring of 1882 to study the metamorphic schists, identifying a third granulitic group alongside the talco-micaceous and hornblende schists and mapping the faulted boundary between the Old Lizard Head Series and the amphibolite east of Polpeor. He observed that faults abound in the Lizard District, noting them in almost every cove and sea-chasm, echoing the observations Sedgwick had made six decades earlier. Some of his interpretations proved remarkably prescient, while others, such as his reading of current-bedding in the hornblende schists and his insistence on a conformable sedimentary sequence, were later overturned. Yet by the close of 1883, the stage had been set for the vigorous debates of the late nineteenth and early twentieth centuries, and the Lizard’s ancient ocean floor had begun, at last, to yield its secrets.

Subject of Research: History of nineteenth-century geological investigations of the Lizard ophiolite complex in Cornwall, England

Article Title: Geological investigations of the Lizard District, Cornwall, England: 1818–1883

Article References: Drummond, C. N. (2025). Geological investigations of the Lizard District, Cornwall, England: 1818–1883. History of Geo- and Space Sciences, 16(2), 65-79. https://doi.org/10.5194/hgss-16-65-2025

Image Credits: AI Generated

DOI: 10.5194/hgss-16-65-2025

Keywords: Lizard District, Cornwall, ophiolite, geology history, serpentine, Adam Sedgwick, Thomas Bonney, petrography, Variscan orogeny, oceanic crust, metamorphism, Henry De la Beche

The scale of the problem is sobering. Researchers estimate that around 95,000 diving seabirds are incidentally caught and drowned in gillnets around the coast of Europe every year. The phenomenon, known as bycatch, is one of the most pressing yet least visible threats facing marine wildlife globally, affecting a wide range of seabird species well beyond European waters. Unlike seabirds killed in trawl or longline fisheries, where mitigation tools such as bird-scaring lines have already delivered dramatic reductions in mortality, gillnets have long proved stubbornly resistant to practical solutions. The gear operates silently and largely unseen, and any device deployed to protect birds must survive harsh conditions at sea while never interfering with the fishers’ ability to work.

That challenge is precisely what motivated an eight-year collaboration between scientists at Fishtek Marine, a Devon-based company and global leader in marine conservation technology, and the RSPB, the UK’s nature conservation charity. The fruit of that partnership is the Looming Eye Buoy, or LEB, a floating deterrent with a deceptively simple design philosophy. The buoy carries a spinning head that creates an animated eye effect on the water surface. To a diving bird approaching from the air, the looming eye mimics the gaze of a potential predator, triggering an instinctive avoidance response that steers the bird away from the patch of water where a gillnet is set. The concept draws on well-established principles of predator recognition in birds, in which large eye-like patterns reliably provoke escape behaviour across many species.

The research team did not rely on a single design. Alongside the LEB, they trialled an alternative deterrent built from a commercially available kite shaped like a bird of prey, known as the scarybird kite. Towed or flown above the fishing operation, the kite presents the silhouette and movement of a raptor, exploiting the same evolutionary wariness that keeps small birds alert to overhead predators. Testing two distinct approaches, one visual lure anchored at the surface and one aerial mimic, allowed the scientists to compare how different deterrent strategies performed under real commercial fishing conditions rather than in idealised experimental settings.

The trials themselves were a model of industry-science collaboration. Over two years, ten Cornish fishermen fitted cameras to their boats and collected data on how the devices affected seabird bycatch during normal fishing operations. This onboard monitoring was essential, because bycatch is rare and patchy enough that reliable measurement demands sustained observation across many fishing events. The resulting dataset was analysed by scientists at the University of Exeter, who quantified the reduction in risk for the two species most frequently caught in the region’s gillnet fishery: guillemots and razorbills, both members of the auk family that pursue fish underwater using their wings.

The results were striking. Both devices decreased the risk of guillemots and razorbills being caught in nets by roughly two thirds. Specifically, the chances of a bird being caught fell by 59 percent when Looming Eye Buoys were deployed and by 71 percent when the scarybird kites were used. For a conservation problem that has resisted mitigation for decades, reductions of this magnitude from inexpensive, low-tech floating deterrents represent a genuine breakthrough. Crucially, the devices achieved these gains without halting fishing, meaning that livelihoods and conservation goals could advance together rather than in conflict.

Perhaps even more valuable than the headline reduction figures was a second discovery buried in the data: bycatch in Cornwall is intensely seasonal. The analysis showed that most seabirds were caught during the winter months, when auks gather in large numbers in Cornish waters. This pattern transforms the economics and logistics of protection. Rather than requiring deterrents on every gillnet vessel year-round, conservation effort can be concentrated in the seasons and locations where risk peaks, making deployments targeted, efficient and far cheaper. Tom Horton, lead author from the University of Exeter, said the study provides some of the strongest evidence to date that simple, practical deterrents can substantially reduce seabird bycatch in gillnet fisheries, and that by identifying when and where bycatch risk is highest, there is now a clear opportunity to target mitigation measures where they deliver the greatest conservation benefit for vulnerable seabird populations while encouraging sustainable fishing practices.

Tom Hooper, senior fisheries scientist at Fishtek Marine, emphasised that the trials showed floating deterrents can make a real difference in protecting seabirds from getting caught in fishing gear, and that one of the most significant results was demonstrating how bycatch concentrates in key locations at specific times of year, allowing deterrent efforts to be directed and efficient. He also stressed a practical truth of working at sea: any technology deployed on fishing boats must be simple and robust. Working hand in hand with fishermen, he noted, taught the team a great deal about how the devices were actually used, enabling refinements that fit the operational needs of the crews who must handle the gear in rough weather and tight schedules. Pete Kibel, co-founder and director of Fishtek Marine, added that the collaboration with the fishing industry, the RSPB and the University of Exeter will continue with the aim of further improving the devices’ efficiency.

The fishermen themselves emerged as enthusiastic partners rather than reluctant subjects. Micky Bacon, a fisherman from Mousehole in Cornwall who took part in the trials, said he became involved because the sea is his workplace and it is important that fishermen participate in projects that can affect how they work and help improve the environment. He added that the trial was a good opportunity to show people outside the industry that fishermen do not just want to catch fish, but also want to be part and parcel of improving the environment. That goodwill matters, because the long-term success of any bycatch mitigation ultimately depends on the crews who must deploy the gear day after day.

The study also builds on a remarkable international track record. The RSPB, as host of the BirdLife International Marine Programme, has been instrumental in deploying bird-scaring lines around the world, an approach that has reduced seabird bycatch by 98 percent in Namibian longline fisheries and by 95 percent in South African trawl fisheries. Yann Rouxel, Bycatch Programme Manager at the RSPB, said that after more than a decade of research into gillnet bycatch and its solutions, it is rewarding to see the work moving towards real-world implementation, noting that while existing technology has cut seabird deaths in trawl and longline fisheries by over 90 percent, gillnets have proved a real challenge and pose a significant threat to seabirds in the UK. He described the performance of the LEB and the kite as a major milestone in reducing bycatch without impeding gillnet fishers while at sea. The latest study was funded by the Defra Fishing Industry Science Partnership programme and Schmidt Marine Technology Partners, and with winter deployments now guided by hard data, the floating scarecrow and its raptor-shaped rival may soon become standard kit on gillnet boats, turning a decades-old conservation deadlock into one of the most encouraging seabird success stories in years.

Subject of Research: Testing floating visual deterrents to reduce seabird bycatch in gillnet fisheries

Article Title: Scientists develop ‘floating scarecrow’ to protect threatened seabirds

Article References: Scientists develop ‘floating scarecrow’ to protect threatened seabirds. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: seabird bycatch, gillnet fisheries, Looming Eye Buoy, guillemots, razorbills, Cornwall, Fishtek Marine, RSPB, University of Exeter, Conservation Letters, marine conservation, fishing technology