Groundwater Quality Processes and Contaminated Land Assessment

Groundwater quality is governed by the interplay of natural hydrogeological processes and anthropogenic pressures arising from contaminated land. Rainfall infiltration, mineral dissolution and redox reactions control the background chemistry in aquifers, while land‐use activities can introduce nutrients, heavy metals and organic pollutants. Assessment of contaminated sites requires the characterisation of pollutant sources, pathways through the vadose zone and transport within groundwater flow regimes. Modern frameworks integrate field measurements, geophysical and geochemical tracers, conceptual and numerical models to map contaminant plumes, quantify uncertainty and prioritise remediation. Vulnerability and risk assessment combine index‐based methods with process‐oriented simulations to evaluate the susceptibility of aquifers to pollution and the potential impact on ecosystem and human health. Effective contaminated land management integrates monitoring networks, site‐specific modelling and adaptive remediation techniques—from source containment and reactive barriers to pump‐and‐treat and passive bioremediation—to protect water supplies and support sustainable land use.

Research from Nature Portfolio

Identification of pollution sources in aquifers has been advanced by applying the principle of reciprocity to solute transport equations. This approach enables the reconstruction of point‐source coordinates, release history and associated fluxes from transient concentration data, even in the presence of limited field observations and multiple source scenarios. The method yields linear equations for unknown source parameters, offering a computationally efficient alternative for site investigations.

A large‐scale survey of freshwater springs in a mountainous catchment used water quality indices and spatial analysis to evaluate hundreds of springs. Hydrochemical facies—such as calcium–magnesium–bicarbonate and sodium–bicarbonate types—were correlated with geology, anthropogenic influence and climate variables. The inventory revealed that a majority of springs provide water of excellent or good quality, highlighting their potential role in meeting future demand under climate stress.

Insights into the deep crustal permeability have been gained by coupling noble gas–derived residence times with hydraulic data. In Precambrian rocks to depths exceeding 1 km, permeability was found to be an order of magnitude lower than expected, showing no clear exponential decay with depth. This limited fluid exchange has implications for the vulnerability of deep aquifers to modern contamination and the transport of solutes and microbes.

Groundwater Quality Processes and Contaminated Land Assessment publication trend

The graph below shows the total number of articles in groundwater quality processes and contaminated land assessment across all publications each year (not limited to Nature Index journals).

Technical terms

Aquifer: A subsurface geological formation that stores and transmits significant quantities of groundwater.

Geochemical fingerprinting: Use of chemical and isotopic tracers to distinguish and apportion sources of groundwater contamination.

Inverse modelling: Computational technique that infers unknown source characteristics by minimising misfit between measured and simulated concentrations.

Hydrochemical facies: Classification of water types based on dominant ion composition, reflecting the controlling geochemical processes.

Vulnerability index: A composite metric that ranks zones of an aquifer according to their susceptibility to contamination.

References

1. Assessment of Groundwater Contamination Risk in Oilfield Drilling Sites Based on Groundwater Vulnerability, Pollution Source Hazard, and Groundwater Value Function in Yitong County. Water (2022).
2. Impacts of climate change on groundwater flooding and ecohydrology in lowland karst. Hydrology and Earth System Sciences (2021).
3. Identification of aquifer pollution’s point sources with the reciprocity principle. Scientific Reports (2022).
4. Solving Inverse Problems of Unknown Contaminant Source in Groundwater-River Integrated Systems Using a Surrogate Transport Model Based Optimization. Water (2020).
5. The low permeability of the Earth’s Precambrian crust. Communications Earth & Environment (2023).
6. A critical appraisal of the status and hydrogeochemical characteristics of freshwater springs in Kashmir Valley. Scientific Reports (2022).