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This study investigates the solid phase characteristics and release of heavy metals (i.e., Cd, Co, Cu, Cr, Mo, Ni, Pb, and Zn) and arsenic (As) from sludge samples derived from industrial wastewater treatment plants. The emphasis is determining the influence of acidification on element mobilization based on a multidisciplinary approach that combines cascade and pH leaching tests with solid phase characterization through X-ray diffraction (XRD), field emission gun electron probe micro analysis (FEG-EPMA), and thermodynamic modeling (Visual MinteQ 3.0). Solid phase characterization and thermodynamic modeling results allow prediction of Ni and Zn leachabilities. FEG-EPMA is useful for direct solid phase characterization because it provides information on additional phases including specific element associations that cannot be detected by XRD analysis. Cascade and pH leaching test results indicate that disposal of improperly treated sludges at landfills may lead to extreme environmental risks due to high leachable concentrations of Zn, Ni, Cu, Cr, and Pb. However, high leachabilities under acid conditions of Ni and Zn as observed from pH leaching test results may provide a potential opportunity for acid extraction recovery of Ni and Zn from such sludges. [ABSTRACT FROM AUTHOR]

In the present study, the REC (Risk reduction, Environmental Merit and Costs), ReCiPe and PRINCETMmethods for the estimation of the environmental, health and financial impacts of a soil remediation process have been evaluated. The evaluation was based on a case study in which a choice had to been made between soil excavation and steam extraction for the remediation of a former oil and fat processing plant. The example shows that it is complicated to come to one overall best remediation option, especially when different stakeholder preferences have to be taken into account. Results of the case study suggest that, besides environmental and human health and cost, the financial risk associated with the remediation project is also an important aspect to include in the evaluation. [ABSTRACT FROM AUTHOR]

In the present study, the relationship between heavy metals (As, Cd, Cr, Cu, Hg, Pb, Ni, Sn and Zn) and major elements and the location and/geological substrate of 105 river sediments in Flanders was investigated. Factor Analysis was used to divide the dataset into four components: a first component including clay, organic matter, Na, Ca, K and Mg, a relationship between Fe, As and Cd, an anthropogenic factor (including Cu, Hg, Pb, Sn and Zn) and finally the pH and insoluble residue. Regression equations were constructed, using major elements such as Fe and Ca as independent variables, besides more classical explaining variables such as clay content (< 2µm fraction), organic matter content and pH. Most heavy metal concentrations could be predicted very well by the independent variables, except Zn, Se and Sn. The results from this study, performed on a dataset of 105 riverbed sediments, indicate that, besides organic matter and clay content, other variables such as the total Fe and Ca content can be relevant parameters to predict heavy metal concentrations in sediments. The more general applicability of the obtained regression equations should be verified, and the inclusion of Fe and Ca in regression equations that are applied for the standardization of total metal concentrations in soils and sediments, should be considered. [ABSTRACT FROM AUTHOR]

Abstract: pH is one of the key parameters that determines heavy metal mobility in soils, sediments and waste materials. In many respects leaching behaviour as reflected by the pHstat leaching tests provide a better means of assessing environmental impact than analysis of total elemental composition. This paper discusses the use of pHstat leaching tests as a tool to assess the potential mobilisation of trace metals from soils, sediments and waste materials. The possibilities of pHstat leaching tests are illustrated by means of different examples. The mathematical fitting of metal leaching behaviour from soils and sediments enabled a distinction between 5 groups of elements with a different leaching behaviour, which could be related to ‘pools’ with different reactivity. Contrary to single and sequential extractions, where pH is difficult to control, the reactivity and mobility of metals at a user-defined pH can be investigated. Moreover, the potential buffering capacity of the sample and its sensitivity to pH changes as a result of external stresses (e.g. soil acidification, liming) can be estimated. A multidisciplinary approach combining mineralogical analysis (X-ray diffraction) with chemical analysis, pHstat leaching tests and geochemical modelling (MINTEQA2) can provide information on the solid-phase speciation and reactivity of heavy metals in soils, sediments and waste materials. Besides the influence of pH on heavy metal leaching behaviour, additional information on heavy metal leachability and retention by the solid matrix was obtained from the kinetics of metal release during a pHstat test. [Copyright &y& Elsevier]

Abstract: Element release from seriously contaminated sediments (especially with Cd, Zn and As) originating from two rivers in northern Belgium was investigated. Oxidation experiments that simulated the deposition of dredged sediments on land or the resuspension of riverbed sediments were performed in the laboratory. The oxidation of anoxic sediments during pHstat tests and the comparison of pHstat leaching in fresh (anoxic) and air-dried (oxic) sediments provided additional information on the changes in heavy metal and As mobility and speciation during oxidation. One of the sediments (GB(rs)) was characterised by a pH-decrease from pH 7.2 to pH 5.9 upon resuspension, while the pH of the other sediment (GL(rs)) did not decrease significantly. Although the release of Cd and Zn was influenced by pH, redox potential was also an important parameter in determining Zn- and Cd-release upon oxidation. In sediment (GB(rs)), Cd and Zn were only released after 48h of resuspension, when the pH decreased to a value of 5.9. Even when the sediment/water suspension was titrated to pH 4 or 6 during oxidation, it took more than 12h to have a substantial release of Cd. The apparent correlation in the release of indicates the association of Zn and Cd with sulphides. From an environmental point of view, especially Cd seems of concern because of the rather elevated concentrations that are released into the porewater and into the suspension upon oxidation. Contrary to other elements such as Zn and As, Cd is not removed from the suspension by coprecipitation and/or readsorption with precipitating Fe-(hydr)oxides within the time span of the observations. [Copyright &y& Elsevier]

The geochemical and mineralogical characterization of mine waste provides essential information to understand the environmental and health impacts and to adequately manage present and historical mine waste sites. In the present study, mine waste samples from a former Zn Pb mining site were subjected to different types of leaching tests, an in-vitro bioaccessibility test, and a mineralogical analysis. The samples were characterized by elevated pseudo-total Pb (up to 51,800 mg/kg), Zn (up to 60,100 mg/kg), Cd (up to 429 mg/kg), and As (up 3170 mg/kg) concentrations, and contained, among other minerals, cerussite (PbCO 3) and galena (PbS). Lead is not only present in abundant concentrations, but also in highly bioaccessible forms, as determined from the in-vitro bioaccessibility test. This indicates the high risks posed in the case of ingestion of fine dust particles. The partial dissolution of the Pb-bearing minerals as a function of pH was modeled using PHREEQC geochemical software and was compared with experimental data. The high Pb release is mainly controlled by the dissolution of cerussite, even at natural pH values. X-ray diffraction analyses revealed that the amount of cerussite decreased (by ≥50%) in all samples as a consequence of leaching with water. Other Pb and Zn minerals present in the samples also dissolved when extracted with water, but not to the magnitude of cerussite. Although the mining site has been inactive for over 100 years, the high concentrations of metal(loid)s within the samples are still evident. Not only are the metals present in high concentrations, but also as mobile forms, especially when pH changes. This study proved to be essential in understanding the different parameters controlling metal(loid)s and in identifying the potential threats the mine waste poses to human health and the environment. From this overall assessment, proper methods for an effective recovery or reprocessing of the mine waste can be further evaluated. Unlabelled Image • High leaching of As, Cu, Cd, Pb and Zn under acidic conditions (pH < 5). • Pb leached during the Toxicity Characteristic Leaching Procedure exceeds threshold. • High Pb release is mainly controlled by the dissolution of cerussite (PbCO 3). • Bioaccessible Pb fraction represents 76 to 98% of the pseudo-total concentration. [ABSTRACT FROM AUTHOR]

Application of pHstat-experiments on soil samples of two heavily contaminated sites in northern Belgium (Flanders) was used to make long-term risk predictions of environmentally relevant heavy metals (Pb, Cu, Ni, Zn, Cr) and arsenic. Implementation of the results of other techniques (sequential extractions and mineralogical research) and geochemical modeling with MINTEQA2 was used to obtain a refined understanding of the geochemical association and the processes that control pH-dependent leaching characteristics of the contaminants. The soil on the first site (a former arsenic refinery in Reppel) was extremely polluted with As, Cu (percentage level), Co and Ni (>0.5%) and leaching of contaminants, which is already alarming, will further increase in the near future by soil acidification. The second site was contaminated with so-called burnt pyrite (sulfuric acid industry) containing high concentrations of Pb, Cu, As and Zn (>0.1%) and a serious threat of metal leaching will manifest if no measures are taken. The kinetics of buffering reactions were evaluated by mathematically fitting of the titration curves. Thereby, two independent proton buffer reactions (rapid and slow) were differentiated and quantified. In the paper, some aspects of the pHstat-procedure were also reconsidered and evaluated. It was shown that one of the critical parameters, namely the duration of the leaching, needs to be extended to 96 h. A 24-h test was observed to be inadequate in assessing heavy metal release properly. [Copyright &y& Elsevier]

Travertines and their springs are rarely investigated as a source of toxicity. Remarkably high contents of As (up to 10 g/kg) have been found in travertine deposits and associated spring waters, nearby Ghorveh city (western Iran). Two types of travertines were distinguished: (i) Fissure ridge travertines, in areas with a carbonate-dominated basement, are characterized by a relatively low content and leaching of As. Their spring waters contain > 150 µg/L of As; (ii) Mound travertines, rich in non-carbonate impurities, occur in areas with volcanic substrates and contain high As concentrations (on average ~1,500 mg/kg) with high leachability. Their spring waters have lower As concentrations than equivalent fissure ridge waters. Principal Component Analyses of the elemental and mineralogical composition show the unstable association of As over a wide range of pH values to non-carbonate related elements, in particular iron, related to clay minerals. The high potential release of As may result in adverse ecotoxicological effects in surrounding agricultural soils and crops. An ecological risk assessment confirms the enrichment and very high potential ecological risk of As around mound carbonates. The human health risk assessment based on calculation via exposure factors suggests adverse non-carcinogenic and high carcinogenic risk with regard to As, both for adults and children. ga1 • Curiously high arsenic content found in travertine geobodies in the same vicinity. • Volcanic substrate main source for high arsenic content. • pH-dependent leaching tests and single extractions indicate high arsenic mobility. • Ecological risk assessment of arsenic reflects high potential ecological risk. • Human health risk assessment reveals adverse non- and high-carcinogenic risks. [ABSTRACT FROM AUTHOR]

This study investigates the leaching of main and trace elements from inorganic polymers made with an iron rich, fumed, > 90% amorphous slag. Different inorganic polymer binders were synthesized, varying the amount of the activating solution and the silica over sodium oxide ratio from 1.6, to 1.8, to 2.0, with constant water content of ±63%. Cascade and column leaching tests were performed in combination with geochemical speciation modeling (Visual MINTEQ) with the aim to understand the speciation of the elements in the inorganic polymer and their leaching behaviour as a function of pH. This would allow to identify the elements which would be the major issue with respect to leaching when the slag will be used in a construction material. The formed inorganic polymer was able to immobilize cationic elements such as barium, copper, magnesium, manganese, and zinc, in the pH range 7–12.5 due to adsorption. Elements such as antimony, arsenic, phosphorus, molybdenum, and vanadium were easily leached out in column and cascade leaching tests, because they most likely occurred as anions in the pore solution. Lead, chromium, and titanium were immobilized in the binder or in crystalline phases in the pH range 3.5–12.5. The study shows that there are multiple factors that affect leaching, the most important of which is shown to be the nature (cationic or anionic) of the elements and the morphology of the matrix. Anions that are present as trace elements (<0.1 wt%) can pose a potential threat in valorising these slags and actions should be taken, either at the metallurgical process itself or downstream, at the synthesis of the inorganic polymers. On the other hand, the results for the cationic species suggest that they are effectively immobilised in most of the cases and for a wide pH range. Image 103337 • Barium, copper, magnesium, manganese and zinc are immobilized due to adsorption. • Antimony, arsenic, phosphorus, molybdenum, and vanadium are mobilized as anions. • Chromium, lead and titanium are immobilized in the binder or in crystalline phases. • Trace elements (<0.1 wt%) can pose a potential treat in valorizing these slags. [ABSTRACT FROM AUTHOR]

Sustainability has increasingly gained momentum as an underlying framework to orient decisions and actions in environmental management. However, while acting in view of sustainability goals is a noble intention, both the conceptualization and the implementation of sustainability remain a subject of debate. This is partly due to the widespread lack of consideration for its social dimension and the interactions this has with the environmental and economic dimensions. To this end, the Community Capitals Framework and other asset-based approaches are often used to deal with these problematic aspects of sustainability in environmental management. Through a systematic review of scientific peer-reviewed articles, this paper investigates the conceptual and practical application of such approaches. Results from our analysis show that different declinations of community capitals exist within environmental management. In all the forms they assume in the 42 frameworks identified, their employment seems effective in promoting the inclusion of social, economic and environmental dimensions when conducting sustainability assessments. However, we identified two main difficulties that challenge the application of asset-based approaches in practice. First, in most cases, capital assessment is not carried out in the planning phase of an environmental intervention in order to identify community resources; capitals are employed instead to measure the impact of an ecological change ex-post, thus being discordant with their theoretical foundations. Second, the existence of a vast array of terms to refer to community assets creates disorientation among exponents of different stakeholder groups and hinders a practical and effective application of this concept. On the basis of our results, we claim the importance of conducting community resources assessment and stakeholder consultation at different times and through practice oriented approaches and cross-silos communication efforts in order to develop a shared understanding of the problem and facilitate sustainable, adaptive and participatory approaches to environmental management • Asset-based approaches promote the inclusion of social sustainability. • Discrepancies between their theoretical and empirical application exist. • Lack of a priori assessments of community resources and concordant terminology. • Participation as information exchange for transformative management. [ABSTRACT FROM AUTHOR]

Circularity of raw materials starts with a zero-waste approach to any (potential) resource. The increasing pressure on the primary raw materials sector and external market dependence can ultimately lead to scarcity of natural resources. To minimise this pressure, alternative materials need to be mapped, characterised, and valorised. Construction and demolition waste and mining waste are currently the biggest waste streams in the EU27 and can lead to environmental, health, and social hazards. The purpose of this study is to evaluate the sustainable use of (clean) sulphidic mining waste materials in facing bricks. After materials' characterisation, a company-specific blend for facing bricks has been modified on a lab scale, by partly replacing primary raw materials with mining waste materials (Plombières tailings and Neves Corvo waste rocks). The production processes, product quality, and environmental performance of waste-derived bricks were assessed and compared to standards and regulatory limits. A cradle-to-gate life cycle assessment (LCA) was performed to evaluate the environmental profiles of the best performing waste-derived bricks compared with standard bricks. Results show the suitability of using the untreated Plombières tailings material in facing brick blends, giving satisfactory technical and aesthetical properties, and complying with environmental regulations for service, 2nd life, and end-of-life stages. According to the LCA, facing bricks made with 40 wt% Plombières tailings demonstrated better environmental performances than standard bricks. The pre-treated Neves Corvo waste rock materials were unsuitable for facing bricks due to the high sulphur and metal(loid)s content that caused aesthetical and chemical-environmental problems. [Display omitted] [ABSTRACT FROM AUTHOR]

• Bioleached sulfidic mine tailings can affect the hydration process. • X-ray µCT show mine tailings strongly influence the porosity of final products. • Up to 20 wt% mine tailings can be incorporated with high compressive strength (90 MPa). • End-of-life leaching test was performed on synergy samples. • High immobilization of metal(loid)s including arsenic under acidic conditions. Sulfidic mine tailings are potential waste materials from mining and mineral processing, and they can contain a high content of sulfur and metal(loid)s, even after bioleaching. Due to the large amount of tailings waste from historical mining, it is crucial to find alternative methods for utilizing such waste rather than permanent storage in tailings impoundments. One-part alkali-activated slag mortars are promising co-binder systems for the recycling of sulfidic mine tailings thanks to their practicability, easy transportation, and user-friendly production. In this work, up to 50 wt% mine tailings were incorporated into alkali-activated blast furnace slag mortars. C-(N)-A-S-H gels were formed in all final samples with hydrotalcite zeolites. Tailings hardly participate in alkali activation, but they do have a considerable influence on physical and chemical properties. The 20 wt% tailings-containing sample showed the highest compressive strength of 91.1 MPa after 90 days of curing. The results of isothermal calorimetry indicate that incrementally increasing the percentage of tailings promotes the pre-induction reaction but hinders the slag hydration process. In addition, the results of X-ray microcomputed tomography showed higher porosity when the mortar contains more tailings; thus, the sample with 10 wt% mine tailings showed the lowest porosity. According to the European Union batch leaching test, up to 20 wt% bioleached sulfidic mine tailings can be valorized in a co-binder system while remaining below the nonhazardous waste thresholds. [ABSTRACT FROM AUTHOR]

The presence of Naturally Occurring Radionuclides (NORs) in geothermal fluids is a recurring issue in geothermal projects all over the world. During the first pumping tests of the production well MOL-GT-S1-01 at the Balmatt geothermal plant (Mol, Belgium) in 2015, the geothermal water was transferred towards a nearby basin. The original geothermal fluid was characterized by a226Ra concentration of ~170 Bq L−1 (February 2019). In the meantime, the water in the basin was exposed to multiple cycles of rainfall and evaporation. In June 2019, the concentration of 226Ra in the basin water was ~24 Bq L−1. As the concentration of the water is still too high to be discarded as non-radioactive waste water, finding a solution to remove the radium from the basin water is required. In order to achieve this objective, two resins, namely the MnO 2 -PAN resin and the TK101 resin, were tested for their sorption capacity to remove the 226Ra by using 133Ba as proxy in batch-type experiments performed in the laboratory. The TK101 resin did not show a sufficient sorption capacity for 133Ba and is therefore not considered to be useful to remove 226Ra from the basin water. The MnO 2 -PAN resin however, showed promising results. A sorption yield of 86% was reached at pH 9.2 after a contact time of one week. At high pH, some co-precipitation of 133Ba with carbonate minerals comprising significant amounts of Ca2+ and Mg2+ was observed. Total sorption was higher at pH = 9.2 (maximum sorption) than at the pH of the basin water (pH = 7.5). Even at high Ca2+ concentrations in the solution (i.e. 5 g L−1), there was almost no competition of Ca2+ for Ba2+ sorption sites on the resin. The modelling of the sorption edge experiments with the MnO 2 -PAN resin showed that mainly Cu and Mn were competitive for the sorption sites at low pH values (2.0 ≤ pH ≤ 4.5), while at acid to neutral pH values (4.5 ≤ pH ≤ 7), Zn and Ni became more competitive. At high pH values (pH ≥ 7.0), Cd started to compete with Ba for the sorption sites of the resin. The modelling of the kinetic experiments showed that these results could best be described by a pseudo second-order kinetic model of the form d q d t = k 2 (q e − q t) 2. • 133Ba/226Ra can be effectively removed from waste water using the MnO 2 -PAN resin. • The TK101 resin showed low sorption of 133Ba due to competition by other cations. • Highest sorption values (86%) are achieved at pH = 10 with the MnO 2 -PAN resin. • 5–10% of 133Ba co-precipitates with carbonate minerals at pH ≥ 10. • Sorption can be described by a second-order kinetic model. [ABSTRACT FROM AUTHOR]

The CO 2 Performance Ladder (CO 2 PL) is a CO 2 management tool that helps companies in improving the environmental performance of projects and business operations. Since the summer of 2020, it can be applied to tenders for soil remediation projects commissioned by the Public Waste Agency (OVAM) of Flanders (Belgium). The CO 2 PL supports organizations in setting up a CO 2 management system, calculating their carbon footprint and achieving CO 2 reductions. However, at present, little information is available about the application of this instrument to the soil remediation sector. Carbon footprint calculators are already commonly applied to evaluate soil remediation projects, but have a narrower scope and system boundaries, as they are only meant to calculate the carbon footprint of soil remediation projects, and not of all business operations. Keeping these differences in mind, the CO 2 PL was compared with other evaluation tools (the CO 2 calculator, the Sustainable Remediation Tool (SRT) and the Spreadsheets for Environmental Footprint Analysis (SEFA)), which are used to calculate the carbon footprint of soil remediation projects. The comparative analysis consists of a qualitative analysis and a quantitative carbon footprint calculation based on data from two case studies in Flanders (Belgium). The results show that besides differences in objectives, scope and required input data, the calculated carbon footprint of the remediation project differs between the instruments. Use of different conversion factors can result in significantly different results. Only some of these differences in the conversion factors are inherently related to regional differences. Especially for more complex remediation projects, in which less conventional techniques/materials are used, CO 2 conversion factors are sometimes not consistent, or simply lacking. A systematic inventory of relevant emission factors, specific for the soil remediation sector, would improve the application of carbon footprint calculations and support the implementation of these kinds of evaluation instruments in the soil remediation sector., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Total element concentrations by themselves are not always good predictors of toxicity and are therefore not suitable for eco- and/or human toxicological risk determination. In addition, despite the growing call for harmonization, countries show significant variation in risk assessment tools, screening/background values, protocols and legal management of soils. By incorporating mobility and bioaccessibility/availability into soil risk assessments, location-specific physico-chemical and geological conditions can be considered in routinely applied general risk assessment methodologies. Minette soils and rocks are a great case in point since they often are associated with high geogenic As concentrations and consequently potential risks. Minette iron ores form the world largest Fe ore deposits since the "great oxidation". For the first time, oral bioaccessibility during direct ingestion was assessed on Minettes from Luxembourg by applying the in vitro Solubility/Bioavailability Research Consortium (SBRC) method. Out of > 180 samples, 25 representative samples were selected providing a unique dataset which showed an average gastric bioaccessibility of ∼10% (7.8 ± 4.0 mg/kg) of the total As-concentration, with a maximum of 45% (17.9 mg/kg). Of importance is that bioaccessibility of As in Minette rocks and soils are controlled by, and can be estimated from, lithology, mineralogy and total Ca content. Soils and ooid grainstones with an iron oxide or clayey matrix, are characterized by average gastric bioaccessible As concentrations < 6 mg/kg. Gastric As bioaccessibility is highest in Fe-bearing calcite-cemented bioclastic grainstones (∼12 mg/kg). Importantly, for all samples the maximal bioaccessible As concentrations remain below the threshold from which significant adverse non-carcinogenic and/or carcinogenic health effects are expected. These new results are in strong contrast with what total As concentrations might suggest. Considering bioaccessibilities, consequently, can help to avoid disproportionate, costly and environmentally impacting risk management strategies. Furthermore, this study illustrates the importance of cross-disciplinary collaboration between geo- and health scientists., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Hannes Claes reports financial support was provided by Environment Agency Luxembourg. Pol Tock reports a relationship with Environment Agency Luxembourg that includes: employment., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Proper management and storage of mine waste, e.g., tailings and waste rock, is one of the main issues that mining industries face. Additionally, there is already an uncountable amount of existent historical mine waste, which may, even centuries after the closure of the mine, still be leaching contaminants into the environment. One solution to minimize the risks associated with the mine waste, with also potential economic benefits, is through the valorization of the waste. This can be done by first recovering valuable metals and removing hazardous contaminants. Then, the remaining residue can be valorized into green construction materials, such as geopolymers, ceramics or cement. For some mine waste materials, such as those with only trace levels of metals that are not economically viable to extract, the "waste" can be reused directly without this additional cleaning step. In the present study, mine waste originating from three different sites was characterized and compared with the cleaned mine waste (i.e., cleaned by bioleaching or flotation methods) and with different types of green construction materials containing 13-80 wt% (cleaned and uncleaned) mine waste. Particular emphasis was given to the mobilization of metal(loid)s from the mine waste and construction materials (i.e., ceramics, alkali-activated materials and cement) under different conditions, through a series of leaching tests (i.e., EN 12457-2, US EPA's Toxicity Characteristic Leaching Procedure, and a pH-dependent leaching test). The leaching tests were applied to either mimic current 'natural' conditions at the mining site, conditions in a landfill (end of life) or extreme conditions (i.e., extremely acidic or alkaline pH). Most of the original mine waste samples contain high levels of Pb (18-3160 mg/kg), Zn (66-10500 mg/kg), and As (10-4620 mg/kg). . The cleaning methods were not always efficient in removing the metal(loid)s and sulfur. In some cases, the cleaned mine waste samples even contained higher total metal(loid) and sulfur concentrations than the original mine waste samples. Based on the leaching studies, some alkali-activated materials, ceramics, and cement effectively immobilized certain metals (e.g., <0.5 mg/kg of Pb and <4 mg/kg of Zn). Also, longer curing times of the alkali-activated materials, in most cases, improved the immobilization of metal(loid)s. Additionally, for ceramics, the temperature at which the test pieces were fired (up to 1060 °C), also played a major role in decreasing the mobility of some metal(loid)s, while increasing others (e.g., As, potentially via the structural rearrangement of As and Fe). Overall, through this detailed characterization, the environmental impact from the mine waste to the downstream products was evaluated, determining which valorization methods are the most viable to close the circular economy loop., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Sulfidic mine waste can pose environmental and human health risks, especially when it contains high levels of mobile metal(loid)s. To assess the environmental and health risks of mine waste originating from three historic and active sulfidic Pb-, Zn- and/or Cu-mines in Europe, mineralogical and chemical characterizations were conducted in combination with in vitro bioaccessibility tests, sequential extractions and leaching tests. Results indicated that most samples contained highly elevated levels of metal(loid)s and key minerals consisting of pyrite, sphalerite and cerussite. The orally bioaccessible fraction varied amongst samples: Cd (13-100%), Zn (9-69%), Pb (4-67%), Cu (8-41%) and As (1-11%). Given these bioaccessible levels, the human health risk assessment indicated carcinogenic and non-carcinogenic risks for most investigated samples in a worst-case exposure scenario. The leaching tests revealed a high mobility of metal(loid)s, especially Pb, posing potential environmental risks. The sequential extractions coupled with mineralogical analyses highlighted the highly mobile levels of Cd, Pb and Zn, posing environmental and health risks. Cerussite dissolved in the easily exchangeable fraction, releasing elevated levels of Pb, while pyrite never completely dissolved. In conclusion, the studied wastes pose environmental and health risks, but the high mobility of some elements also provides opportunities for the valorization of the waste., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Developing legislation on soil protection, including soil quality standards, is not straightforward for areas with high geogenic metal(loid) concentrations in rocks and soils. Several rock types in southern Luxembourg (laterally continuous into Northern France and Southern Belgium) contain elevated potentially toxic element concentrations. Toarcian and Aalenian Minette ironstones, and soils on top, possess high As concentrations (average of ~100 mg/kg, maximum up to 278 mg/kg). Liassic shales show high Mo concentrations (up to 60 mg/kg). Preliminary health risk assessments suggest increased potential non-carcinogenic and carcinogenic risks. Trace metal and As anomalies, however, do not necessarily pose human and ecotoxicological risks. Petrographic, mineralogical and chemical analyses show a strong association of As to iron oxides present as ooids and rock matrix. Single extractions with CaCl 2 (0.01 mol/l) indicated the low As mobility in the Minettes. The Minette rocks with 10-40 wt% iron oxides, and a clay content of typically 10-30 wt% strongly bind As. As long as Eh and pH do not drastically change in soils, As mobility will remain low. For soils that developed on Minettes, it is advised to consider Fe-content as well as As mobility for risk assessment and development of legislation on soil protection., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Site contamination is a global concern because of the potential risks for human health and ecosystem quality. Every contaminated site has its own specific characteristics and the increased availability and efficiency of remediation techniques makes the choice of remediation alternative increasingly complicated. In this paper an attributional Life Cycle Assessment (LCA) of the secondary environmental impacts of a site remediation is performed and its results are monetized using two different monetization techniques, namely Stepwise 2006 and Ecovalue 08. Secondly, we perform a social Cost-Benefit Analysis (CBA) on the same case study using the same data sources. The case study used in this paper entails the soil and groundwater remediation of a tar, poly-aromatic hydrocarbons (PAH) and cyanide contamination of a school ground by a former gas plant. The remediation alternative chosen in this case study is excavation with off-site thermal treatment of the contaminated soil. The outcome of the social CBA, stating that the remediation project is socially beneficial in the long term, is critically compared to the outcome of the different LCA monetization methods. This comparison indicates that monetized LCA is a good complement to social CBA when it comes to the assessment of secondary environmental impacts. Combining the two methods provides decision makers with a more extensive and detailed assessment of the soil remediation project., (Copyright © 2017 Elsevier B.V. All rights reserved.)

In Europe alone, there are more than 2,5 million potentially contaminated sites of which 14% are expected to require remediation. Contaminated soil and groundwater can cause damage to human health as well as to valuable ecosystems. Globally more attention has been paid to this problem of soil contamination in the past decades. For example, more than 58 000 sites have been remediated in Europe between 2006 and 2011. Together with this increase in remediation projects there has been a surge in the development of new remediation technologies and decision support tools to be able to match every site and its specific characteristics to the best possible remediation alternative. In the past years the development of decision support tools (DST) has evolved in a more sustainable direction. Several DSTs added the claim not only to denote effective or technologically and economically feasible remediation alternatives but also to point out the more or most sustainable remediation alternatives. These trends in the evaluation of site remediation options left users with a confusing clew of possibly applicable tools to assist them in decision making for contaminated site remediation. This review provides a structured overview on the extent decision support tools for contaminated site remediation, that claim to assist in choosing the most sustainable remediation alternative, actually include the different elements of sustainability proposed in our assessment framework. The review contains an in-depth analysis of thirteen tools specifically developed to assess the sustainability of site remediation alternatives. This analysis is based on six criteria derived from the definition of sustainable development of the Brundtland report. The six criteria were concretized by using the three pillars of sustainability, applied to site remediation according to the SuRF-UK framework, two criteria derived from Life Cycle Assessment and Cost-Benefit Analysis, and an 'User friendly' criterion. These elements come together in a framework, drafted for this study, containing six criteria covering the environmental, economic, social, time, uncertainty aspects and user friendliness of a sustainable site remediation. The main remarks uncovered by this review are the imbalance of used indicators still expressing a strong preference for the environmental aspect at the expense of the economic and social aspects of sustainability, the lack of consistency in the terminology used within the field and the failure in adapting released tools to recent legislation or scientific advancements., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Sustainable remediation requires a balanced decision-making process in which environmental, economic and social aspects of different remediation options are all considered together and the optimum remediation solution is selected. More attention has been paid to the evaluation of environmental and economic aspects, in particular to reduce the human and environmental risks and the remediation costs, to the exclusion of social aspects of remediation. This paper investigates how social aspects are currently considered in sustainability assessments of remediation projects. A selection of decision support tools (DSTs), used for the sustainability assessment of a remediation project, is analyzed to define how social aspects are considered in those tools. The social indicator categories of the Sustainable Remediation Forum - United Kingdom (SuRF-UK), are used as a basis for this evaluation. The consideration of social aspects in the investigated decision support tools is limited, but a clear increase is noticed in more recently developed tools. Among the five social indicator categories defined by SuRF-UK to facilitate a holistic consideration of social aspects of a remediation project only "Human health and safety" is systematically taken into account. "Neighbourhood and locality" is also often addressed, mostly emphasizing the potential disturbance caused by the remediation activities. However, the evaluation of 'Ethics and Equality', Communities and community involvement', and 'Uncertainty and evidence' is often neglected. Nevertheless, concrete examples can be found in some of the investigated tools. Specific legislation, standard procedures, and guidelines that have to be followed in a region or country are mainly been set up in the context of protecting human and ecosystem health, safety and prevention of nuisance. However, they sometimes already include some of the aspects addressed by the social indicators. In this perspective the use of DST to evaluate the sustainability of a site remediation project, should be tuned to the legislation, guidelines and procedures that are in force in a specific country or region., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

A possible solution for the oversupply of dredged sediments is their use as a raw material in brick production. Despite the fact that several examples (e.g., Agostini et al., 2007; Hamer and Karius, 2002; Xu et al., 2014) show that this application is feasible, some economic, technical and social limitations interfere with the development of a market of dredged materials in brick production in Flanders. While we describe the main characteristics of the supply side, we focus on the limitations and barriers from the demand side in the present study. Based on a consumers survey we analyze consumers' risk perceptions and attitudes towards bricks produced from dredged sediments. Consumers in Flanders are rather suspicious with respect to bricks produced from dredged sediments and their risk perception is mainly determined by the possibility of a bad bargain (brick of inferior quality) and the connotation with chemical contamination. The willingness to pay for bricks made from dredged sediments is mainly influenced by the age of the respondents, as well environmental awareness, and the respondents' belief in their ability to influence environmental problems. Sensitization and information of customers seems to be of primary importance to make dredged-sediment-derived bricks a successful product., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Alluvial soils may represent important sinks of contaminants as a result of the deposition of contaminated sediments along the river by overbank flooding or after dredging. Because of the erosion of alluvial deposits or the release of contaminants from sediments, alluvial soils can also be a source of contamination. In this paper, a risk assessment for contaminated (alluvial) soils is presented. The approach, mainly based on physico-chemical soil characteristics, single extractions and leaching tests, is illustrated by means of a case study from four Belgian catchments. The extractions and leaching tests that were used have been validated by European testing programs and can provide valuable information for classifying the potential environmental risks of soils. Irrespective of the location, pH, organic carbon content and 'mobilisable' metal concentrations were the most important factors explaining 'mobile' metal concentrations in the alluvial soils. Additionally, the data of the physico-chemical soil characterization, extractions and leaching tests were combined with local and regional factors to classify the alluvial soils in different categories according to their actual and potential risk for the environment.