Historical soil compaction impairs biogeochemical cycling in restored tidal marshes through reduced groundwater dynamics.

Tidal marshes are often restored on compact agricultural soil that limits tidally induced groundwater dynamics and soil aeration after restoration. We hypothesized that impaired soil aeration affects biogeochemical cycling and leads to altered porewater nutrient concentrations in restored tidal marshes. We studied soil hydraulic properties, groundwater dynamics and porewater nutrient concentrations (nitrogen, phosphorus and dissolved silica) over the course of one year in a natural and a restored freshwater tidal marsh in the Scheldt estuary, Belgium.

Qualitative and quantitative simulation of best management practices (BMPs) for contaminated megasite remediation using the SiteWise™ tool.

Remediation activities, particularly in megasites, may induce substantial secondary environmental impacts that must be addressed for green and sustainable remediation (GSR) practices. Only limited studies are available quantitatively assessing the environmental footprint and environmental benefits of implementing Best Management Practices (BMPs) in megasite remediation. This study used the SiteWise™ tool, a quantitative environmental footprint assessment for scenario simulation and benefit quantification of BMPs, on a contaminated megasite in Hebei Province, China.

Mitigating glyphosate levels in surface waters: Long-term assessment in an agricultural catchment in Belgium.

The increasing concern over pesticide pollution in water bodies underscores the need for effective mitigation strategies to support the transition towards sustainable agriculture. This study assesses the effectiveness of landscape mitigation strategies, specifically vegetative buffer strips, in reducing glyphosate loads at the catchment scale under realistic conditions. Conducted over six years (2014-2019) in a small agricultural region in Belgium, our research involved the analysis of 732 water samples from two monitoring stations, differentiated by baseflow and event-driven sampling, and before (baseline) and after the implementation of mitigation measures.

A spatial approach to identify priority areas for pesticide pollution mitigation.

Identifying priority areas is an essential step in developing management strategies to reduce pesticide loads in surface water. A spatially explicit model-based approach was developed to detect priority areas for diffuse pesticide pollution at catchment scale. The method uses available datasets and considers different pesticide pathways in the environment post-application.

Hysteresis and parent-metabolite analyses unravel characteristic pesticide transport mechanisms in a mixed land use catchment.

To properly estimate and manage pesticide occurrence in urban rivers, it is essential, but often highly challenging, to identify the key pesticide transport pathways in association to the main sources. This study examined the concentration-discharge hysteresis behaviour (hysteresis analysis) for three pesticides and the parent-metabolite concentration dynamics for two metabolites at sites with different levels of urban influence in a mixed land use catchment (25 km) within the Swiss Greifensee area, aiming to identify the dominant pesticide transport pathways. Combining an adapted hysteresis classification framework with prior knowledge of the field conditions and pesticide usage, we demonstrated the possibility of using hysteresis analysis to qualitatively infer the dominant pesticide transport pathway in mixed land-use catchments.

A hybrid monitoring and modelling approach to assess the contribution of sources of glyphosate and AMPA in large river catchments.

Large river catchments with mixed land use capture pesticides from many sources, and degradable pesticides are converted during downstream transport. Unravelling the contribution of pesticide source and the effect of degradation processes is a challenge in such areas. However, insight and understanding of the sources is important for targeted management, especially when water is abstracted from the river for drinking water production.

Application of biodegradation in mitigating and remediating pesticide contamination of freshwater resources: state of the art and challenges for optimization.

In recent years, the application of pesticide biodegradation in remediation of pesticide-contaminated matrices moved from remediating bulk soil to remediating and mitigating pesticide pollution of groundwater and surface water bodies. Specialized pesticide-degrading microbial populations are used, which can be endogenous to the ecosystem of interest or introduced by means of bioaugmentation. It involves (semi-)natural ecosystems like agricultural fields, vegetated filter strips, and riparian wetlands and man-made ecosystems like on-farm biopurification systems, groundwater treatment systems, and dedicated modules in drinking water treatment.

Do ICP-MS based methods fulfill the EU monitoring requirements for the determination of elements in our environment?

Undoubtedly, the most important advance in the environmental regulatory monitoring of elements of the last decade is the widespread introduction of ICP-mass spectrometry (ICP-MS) due to standards developed by the European Committee for Standardization. The versatility of ICP-MS units as a tool for the determination of major, minor and trace elements (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, P, Pb, Sb, Se, Sn, Ti, V and Zn) in surface water, groundwater, river sediment, topsoil, subsoil, fine particulates and atmospheric deposition is illustrated in this paper. Ranges of background concentrations for major, minor and trace elements obtained from a regional case study (Flanders, Belgium) are summarized for all of these environmental compartments and discussed in the context of a harmonized implementation of European regulatory monitoring requirements.

Urban soil exploration through multi-receiver electromagnetic induction and stepped-frequency ground penetrating radar.

In environmental assessments, the characterization of urban soils relies heavily on invasive investigation, which is often insufficient to capture their full spatial heterogeneity. Non-invasive geophysical techniques enable rapid collection of high-resolution data and provide a cost-effective alternative to investigate soil in a spatially comprehensive way. This paper presents the results of combining multi-receiver electromagnetic induction and stepped-frequency ground penetrating radar to characterize a former garage site contaminated with petroleum hydrocarbons.

Quantification and characterization of glyphosate use and loss in a residential area.

Urban runoff can be a significant source of pesticides in urban streams. However, quantification of this source has been difficult because pesticide use by urban residents (e.g.

Oxidation of iron causes removal of phosphorus and arsenic from streamwater in groundwater-fed lowland catchments.

The fate of iron (Fe) may affect that of phosphorus (P) and arsenic (As) in natural waters. This study addresses the removal of Fe, P, and As from streams in lowland catchments fed by reduced, Fe-rich groundwater (average: 20 mg Fe L(-1)). The concentrations of dissolved Fe (<0.

Model-based Scenario Analysis of the Impact of Remediation Measures on Metal Leaching from Soils Contaminated by Historic Smelter Emissions.

A spatially distributed model for leaching of Cd from the unsaturated zone was developed for the Belgian-Dutch transnational Kempen region. The model uses as input land-use maps, atmospheric deposition data, and soil data and is part of a larger regional model that simulates transport of Cd in soil, groundwater, and surface water. A new method for deriving deposition from multiple sites was validated using soil data in different wind directions.

Highly parameterized inversion of groundwater reactive transport for a complex field site.

In this study a numerical groundwater reactive transport model of a shallow groundwater aquifer contaminated with volatile organic compounds is developed. In addition to advective-dispersive transport, the model includes contaminant release from source areas, natural attenuation, abiotic degradation by a permeable reactive barrier at the site, and dilution by infiltrating rain. Aquifer heterogeneity is parameterized using pilot points for hydraulic conductivity, specific yield and groundwater recharge.

Use of online water quality monitoring for assessing the effects of WWTP overflows in rivers.

The effects on river water quality of sewer overflows are not well known. Since the duration of the overflow is in the order of magnitude of minutes to hours, continuous measurements of water quality are needed and traditional grab sampling is unable to quantify the pollution loads. The objective of this paper was to demonstrate the applicability of high frequency measurements for assessing the impacts of waste water treatment plants on the water quality of the receiving surface water.

Corrosion rate estimations of microscale zerovalent iron particles via direct hydrogen production measurements.

In this study, the aging behavior of microscale zerovalent iron (mZVI) particles was investigated by quantifying the hydrogen gas generated by anaerobic mZVI corrosion in batch degradation experiments. Granular iron and nanoscale zerovalent iron (nZVI) particles were included in this study as controls. Firstly, experiments in liquid medium (without aquifer material) were performed and revealed that mZVI particles have approximately a 10-30 times lower corrosion rate than nZVI particles.

Kinetics of dechlorination by Dehalococcoides mccartyi using different carbon sources.

Stimulated anaerobic dechlorination is generally considered a valuable step for the remediation of aquifers polluted with chlorinated ethenes (CEs). Correct simulation and prediction of this process in situ, however, require good knowledge of the associated biological reactions. The aim of this study was to evaluate the dechlorination reaction in an aquifer contaminated with trichloroethene (TCE) and its daughter products, discharging into the Zenne River.

Sustainability appraisal tools for soil and groundwater remediation: how is the choice of remediation alternative influenced by different sets of sustainability indicators and tool structures?

The state-of-the-science in sustainability assessment of soil and groundwater remediation is evaluated with the application of four decision support systems (DSSs) to a large-scale brownfield revitalization case study. The DSSs were used to perform sustainability appraisals of four technically feasible remediation alternatives proposed for the site. The first stage of the review compares the scope of each tool's sustainability indicators, how these indicators are measured and how the tools differ in terms of standardization and weighting procedures.

A GLUE uncertainty analysis of a drying model of pharmaceutical granules.

A shift from batch processing towards continuous processing is of interest in the pharmaceutical industry. However, this transition requires detailed knowledge and process understanding of all consecutive unit operations in a continuous manufacturing line to design adequate control strategies. This can be facilitated by developing mechanistic models of the multi-phase systems in the process.

Predicting longevity of iron permeable reactive barriers using multiple iron deactivation models.

In this study we investigate the model uncertainties involved in predicting long-term permeable reactive barrier (PRB) remediation efficiency based on a lab-scale column experiment under accelerated flow conditions. A PRB consisting of 20% iron and 80% sand was simulated in a laboratory-scale column and contaminated groundwater was pumped into the column for approximately 1 year at an average groundwater velocity of 3.7 E-1 m d(-1).

Self-inhibition can limit biologically enhanced TCE dissolution from a TCE DNAPL.

Biodegradation of trichloroethene (TCE) near a Dense Non Aqueous Phase Liquid (DNAPL) can enhance the dissolution rate of the DNAPL by increasing the concentration gradient at the DNAPL-water interface. Two-dimensional flow-through sand boxes containing a TCE DNAPL and inoculated with a TCE dechlorinating consortium were set up to measure this bio-enhanced dissolution under anaerobic conditions. The total mass of TCE and daughter products in the effluent of the biotic boxes was 3-6 fold larger than in the effluent of the abiotic box.

The addition of organic carbon and nitrate affects reactive transport of heavy metals in sandy aquifers.

Organic carbon introduction in the soil to initiate remedial measures, nitrate infiltration due to agricultural practices or sulphate intrusion owing to industrial usage can influence the redox conditions and pH, thus affecting the mobility of heavy metals in soil and groundwater. This study reports the fate of Zn and Cd in sandy aquifers under a variety of plausible in-situ redox conditions that were induced by introduction of carbon and various electron acceptors in column experiments. Up to 100% Zn and Cd removal (from the liquid phase) was observed in all the four columns, however the mechanisms were different.

Phytoremediation as a management option for contaminated sediments in tidal marshes, flood control areas and dredged sediment landfill sites.

Background, Aim And Scope: Polluted sediments in rivers may be transported by the river to the sea, spread over river banks and tidal marshes or managed, i.e. actively dredged and disposed of on land.

Microbial processes as key drivers for metal (im)mobilization along a redox gradient in the saturated zone.

Two sites representing different aquifer types, i.e., Dommel (sandy) and Flémalle (gravelly loam) along the Meuse River, have been selected to conduct microcosm experiments.

The dynamic water-sediment system: results from an intensive pesticide monitoring campaign.

To gain insight into the dynamics of pesticides in the different compartments of a river system, an intensive monitoring campaign was set up. An extensive dataset is useful when planning to model the fate of pesticides in river systems. In this study we focus on the Nil, a small, hilly basin situated in the central part of Belgium.