Environmental geoscience is the study of how Earth’s physical systems interact with human activity and ecological health. It sits at the intersection of geology, hydrology, soil science, and environmental engineering, applying knowledge of rocks, sediments, groundwater, and surface processes to problems like pollution, natural hazards, climate change, and resource management. The field has grown considerably since the late twentieth century as societies have recognized that nearly every environmental challenge has a geological dimension, whether that is contaminated groundwater flowing through fractured bedrock or a coastline retreating because its sediment supply has been disrupted.
How Mining Shapes Groundwater and What Geoscientists Do About It
One of the field’s longest-standing concerns is acid rock drainage, the acidic, metal-laden water that forms when sulfide minerals in mine waste are exposed to air and moisture. At pyrite mines, for example, the oxidation of iron sulfide can drive groundwater pH down sharply and release dissolved metals like aluminum, iron, copper, cobalt, manganese, and nickel into surrounding aquifers. A study at a pyrite mine in South China showed that groundwater near the acid drainage pond was heavily affected by these soluble metals produced by pyrite oxidation.1PubMed. Impact of acid mine drainage on groundwater hydrogeochemistry at a pyrite mine (South China): a study using stable isotopes and multivariate statistical analyses The contamination does not stay in place; it migrates through subsurface pathways and can reach drinking-water sources kilometers away.
Environmental geoscientists work on both understanding the problem and developing solutions. One promising approach involves coating reactive pyrite surfaces with silica to slow or stop the oxidation process. In laboratory leaching experiments, silica-treated waste rock produced water with a near-neutral pH throughout the entire leaching cycle, while untreated material rapidly acidified. The release of sulfur and toxic metals was also suppressed in the treated samples.2PubMed Central. Prevention of acid rock drainage formation through pyrite inhibition by silica coating Techniques like this illustrate what makes environmental geoscience distinct from pure environmental science: it relies heavily on mineralogy, geochemistry, and an understanding of how rock and water interact at the molecular level.
Soil Contamination and the Plants That Clean It Up
Soil is where geology meets biology, and contaminated soil is one of the field’s major practical concerns. Decades of industrial activity, improper waste disposal, and agricultural chemical use have left heavy metals and organic pollutants in soils worldwide. Environmental geoscientists map these contamination plumes, figure out how pollutants move through different soil types, and evaluate cleanup strategies.
Among the more elegant cleanup approaches is phytoremediation, which uses living plants to extract, stabilize, or break down contaminants. Five distinct methods fall under this umbrella: phytostabilization (immobilizing contaminants in the root zone), phytodegradation (breaking pollutants down within plant tissues), rhizofiltration (filtering contaminants from water through roots), phytoextraction (pulling metals up into harvestable plant tissue), and phytovolatilization (converting pollutants to a gaseous form that leaves through plant leaves).3PubMed. Phytoremediation of heavy metals in soil and water: An eco-friendly, sustainable and multidisciplinary approach The choice among them depends on the type of contaminant, the soil mineralogy, climate, and whether the goal is to remove the pollutant entirely or simply stop it from spreading. A geoscientist’s understanding of soil chemistry and subsurface water flow is critical here because the wrong approach in the wrong soil type can actually mobilize contaminants instead of containing them.
Storing Carbon Underground
Climate change mitigation has pushed environmental geoscience into new territory. Carbon capture and storage is fundamentally a geological enterprise: you need to understand rock porosity, permeability, mineral reactivity, and long-term stability to lock carbon dioxide away for centuries or millennia. Basalt, a common volcanic rock rich in calcium, magnesium, and iron, has emerged as a particularly promising host for carbon sequestration through mineral carbonation. In this process, injected CO₂ reacts with the minerals in basalt to form stable carbonate minerals, effectively turning the gas into rock. This provides a permanent and environmentally safe storage solution because the carbon is locked into a solid mineral structure rather than sitting as a pressurized gas that might eventually leak.4Geoscience Frontiers. The future of carbon capture: Basalt’s role in low-hydration CO2 sequestration
What makes basalt sequestration especially interesting from a geoscience perspective is that massive basalt formations exist on every continent and beneath large areas of the ocean floor. The challenge lies in understanding how the carbonation reaction proceeds under different temperature, pressure, and water-availability conditions underground, and whether it can be scaled up from laboratory demonstrations to industrial volumes. This is classic environmental geoscience work: applying detailed knowledge of rock chemistry and subsurface fluid dynamics to solve a pressing environmental problem.
When Drilling and Injection Trigger Earthquakes
Injecting fluids deep underground is central to several industries, from oil and gas extraction to wastewater disposal and geothermal energy. Environmental geoscientists have documented that these injections can reactivate dormant faults and cause earthquakes in places that previously had no seismic history. The mechanism works through several pathways: the injected fluid increases pore pressure along pre-existing faults, reducing the friction that keeps them locked; it alters the stress distribution in the surrounding rock; and the resulting slow, creeping slip on one fault segment can transfer stress to neighboring faults, potentially triggering a larger seismic event.5International Journal of Mining Science and Technology. Fault reactivation and seismic risks induced by deep reservoir fracturing: Mechanisms, prediction and perspectives
A striking example comes from western Canada, where long-term wastewater disposal triggered an earthquake sequence of 187 events, with magnitudes ranging up to 3.9, in an area with no previous seismic record. Analysis showed that the injection had caused stress changes of up to 10 megapascals and was accelerating the development of entirely new fault structures in the subsurface.6Journal of Geophysical Research: Solid Earth. Long‐Term Fluid Injection Can Expedite Fault Reactivation and Development: Riedel Shear Structures Illuminated by Induced Earthquakes in Alberta, Canada This kind of research has direct policy implications: before approving injection wells, regulators increasingly require geoscientific assessments of nearby fault systems and ongoing seismic monitoring programs.
Coastlines Under Pressure
Coastal geomorphology is another cornerstone of environmental geoscience. Rising seas understandably dominate the public conversation about coastal erosion, but the geological reality is more nuanced. At many locations, the sediment budget, the balance between sand arriving at a stretch of coast and sand being carried away, matters more than sea-level rise does, at least for now.
On the Danish North Sea coast, for instance, a barrier spit called Skallingen grew steadily for three centuries before 1970 but is now eroding at roughly 4.2 meters per year. The primary driver is not the local sea-level rise of about 3.3 millimeters per year but rather a divergence in longshore sediment transport: more sand is being carried away by currents than is arriving. The researchers concluded that the commonly used models linking erosion directly to sea-level rise are insufficient, and that human impacts on sediment supply can cause far greater erosion rates than rising water levels alone.7Journal of Coastal Research. Sea level rise and the sediment budget of an eroding barrier on the Danish North Sea coast
A similar picture has emerged from Brazil’s Hermenegildo Beach, where modeling showed that under current conditions, sediment deficit is the dominant cause of coastal retreat. However, the same models project that as sea-level rise accelerates later this century, the dominant driver will shift. Under high-emission scenarios for 2100, sea-level rise would account for the large majority of shoreline recession, with sediment deficit contributing only about 14 percent of the total retreat.8Brazilian Journal of Oceanography. Modelling the effects of sea-level rise and sediment budget in coastal retreat at Hermenegildo Beach, Southern Brazil The practical takeaway is that coastal management strategies need to address both issues, and the relative importance of each will shift over time. Models of Portugal’s northwestern coast reinforce this, showing that areas with a sediment deficit experience recession even before sea-level effects are layered on, while areas with a positive sediment budget can continue to grow seaward for a time.9Estuarine, Coastal and Shelf Science. Effect of alongshore sediment supply gradients on projected shoreline position under sea-level rise (northwestern Portuguese coast)
Nuclear Waste and the Challenge of Deep Time
Few problems demand as long a time horizon as nuclear waste disposal, and environmental geoscience provides the framework for the leading solution. Deep geological repositories use a multi-barrier system that combines natural geological barriers, typically stable rock formations hundreds of meters underground, with engineered barriers such as corrosion-resistant containers, clay buffer materials, and backfill.10PubMed. Deep geological repositories – A review of design concepts, near-field evolution, and their implications for nuclear waste containment The idea is to prevent radioactive material from reaching the biosphere for tens of thousands of years, far longer than any human institution is likely to survive.
Designing these repositories requires geoscientists to predict how rock, groundwater, and engineered materials will behave over geological timescales. How fast will the metal containers corrode? Will the clay buffer swell enough to seal fractures? Could groundwater chemistry change in ways that accelerate radionuclide migration? Recent research has focused particularly on optimizing the engineering barriers and understanding how key radioactive elements move through different rock and clay combinations.11PubMed. Engineering barriers in deep geological disposal: Implications for radioactive nuclide migration and long-term safety It is, arguably, the most extreme test of whether geoscientific models can be trusted to predict the far future.
Cities as Geological Agents
Urban areas alter the subsurface in ways most people never consider. Buildings, roads, underground infrastructure, and industrial heat all warm the ground beneath cities, creating what researchers call a subsurface urban heat island. Satellite-derived measurements have shown that within the top ten meters of soil and rock, urban areas can run 3 to 5 degrees warmer than surrounding rural land, with an average intensity of about 4.3 kelvin. The warming signal persists year-round at depths between half a meter and ten meters, with seasonal peaks arriving later the deeper you go, roughly 26 days of lag per meter of depth.12Environmental Science & Technology. Satellite-Derived Subsurface Urban Heat Island
This matters because subsurface temperature affects groundwater chemistry, the behavior of underground infrastructure, and even microbial ecosystems beneath our feet. Environmental geoscientists working in urban settings also deal with land subsidence caused by groundwater pumping, another area where the geological and the urban collide.
In California’s San Joaquin Valley, decades of groundwater overdraft have caused severe land subsidence, resulting in millions of dollars of infrastructure damage.13Water Resources Research. Development and Application of a 1D Compaction Model to Understand 65 Years of Subsidence in the San Joaquin Valley The problem is not just sinking land; when an aquifer compacts after being drained, it loses pore space permanently, meaning it can never hold as much water again even if groundwater levels recover. A global mapping study confirmed that this irreversible loss of aquifer storage capacity is widespread wherever pumping has been intense.14Nature Communications. Global land subsidence mapping reveals widespread loss of aquifer storage capacity The geological character of the sediment, whether it is compressible clay or more rigid sand and gravel, determines how much subsidence occurs and how permanent it is.
Microplastics in the Sediment Record
An emerging frontier in environmental geoscience is understanding how synthetic contaminants behave once they reach the sediment layer. Microplastics have been found in sediments from rivers to deep ocean shelves, and their vertical distribution within sediment cores is revealing how they move and accumulate. Off the western Irish continental shelf, about 97 percent of recovered microplastics were found in the top 2.5 centimeters of sediment, with the highest concentration at the water-sediment interface and the uppermost half-centimeter.15Scientific Reports. The Deposition and Accumulation of Microplastics in Marine Sediments and Bottom Water from the Irish Continental Shelf
Inland, the picture is more complicated. Microplastic abundance can vary dramatically between sites and can even show opposite depth trends at different locations. Smaller particles tend to work their way deeper into sediment layers, while larger fragments stay near the surface.16PubMed. Depth profiles of microplastics in sediments from inland water to coast and their influential factors Research along the Norwegian coast has found that seafloor topography and human activities like fishing disturb sediment layers in ways that complicate any neat story about microplastics simply accumulating chronologically. That finding has raised questions about whether microplastic layers in sediment cores can reliably serve as geological markers of human impact.17PubMed Central. Diving into the Depths: Uncovering Microplastics in Norwegian Coastal Sediment Cores
Microbes That Move Carbon and Nitrogen
Not all environmental geoscience is about pollution or hazards. A substantial branch focuses on biogeochemistry, the chemical cycles that sustain ecosystems. Microorganisms drive many of the processes that control how carbon and nitrogen move through watersheds, from decomposing organic matter and producing new biomass to converting nitrogen between its various chemical forms.18PubMed Central. The interplay of carbon and nitrogen cycling driven by watershed microorganisms At the land-sea interface, where rivers meet the ocean, microbial communities also drive the cycling of sulfur alongside carbon and nitrogen, influencing everything from water quality to greenhouse gas emissions.19PubMed Central. Microbially driven organic carbon cycling at the land-sea interface: Advances and an integrated study framework
Understanding these microbial processes is essential for predicting how ecosystems will respond to environmental change. If warming shifts the balance of microbial activity in soils, for instance, it could accelerate carbon release from organic matter and create a feedback loop that amplifies climate change. Environmental geoscientists working in this area tend to combine fieldwork, laboratory geochemistry, and genomic analysis to trace how these invisible communities shape the chemistry of their surroundings.
The Energy Transition’s Geological Footprint
The shift to renewable energy and electric vehicles requires enormous quantities of minerals like lithium, cobalt, nickel, and rare earth elements. Environmental geoscience is central to evaluating the trade-offs involved. Life cycle assessment is a key tool for weighing the environmental costs of extracting these materials against the benefits of the technologies they enable, though a recent review found that applications of this method to critical mineral mining remain inconsistent and limited.20PubMed Central. Holistic, Literature-Informed Critical Mineral Life Cycle Assessment Guidelines: An Essential Foundation for the Energy Transition
The scale of the challenge is becoming clearer. An assessment of the minerals needed for Europe’s energy sector found that the mining operations involved produced direct greenhouse gas emissions of roughly 600 to 1,700 kilotons of CO₂ equivalent in 2019. As demand for clean-energy minerals grows, those direct emissions could increase by a factor of about 1.6 to 1.9 by 2030, and by 2.4 to 4.9 times by 2040. When the full supply chain is included, the additional emissions could reach 8 to 14 million tons of CO₂ equivalent per year by 2040 relative to 2019 levels.21Global Environmental Change. Assessing the social and environmental impacts of critical mineral supply chains for the energy transition in Europe Environmental geoscientists help identify which deposits can be mined with the least ecological disruption, how tailings and waste rock should be managed, and where geological conditions create particular risks of acid drainage or heavy metal release.
Hazard Mapping and Land-Use Planning
At the policy level, environmental geoscience feeds directly into land-use decisions. Multi-hazard mapping combines geological data on flood zones, landslide susceptibility, and seismic risk to identify which areas are safe for development. In one regional assessment, areas rated high or very high suitability for development covered about 54 percent of the total area, while about 15 percent was classified as unsuitable. Troublingly, roughly 35 percent of existing settlements sat in zones with high susceptibility to geo-hazards.22Heliyon. Geo-hazards assessment and land suitability estimation for spatial planning using multi-criteria analysis Findings like this give planners concrete, spatially explicit information about where building is risky and where it is not, translating geological knowledge into decisions that affect thousands of lives.
This policy-facing work also includes environmental impact assessments for proposed mines, dams, and infrastructure projects. Geoscientists evaluate how a project will interact with local geology, groundwater, and slope stability, and their assessments shape the conditions under which projects are approved or denied. In many countries, environmental geoscience has become embedded in the regulatory process itself, making it one of the few earth science disciplines where the research output directly and routinely changes what gets built and where.