Historical mining towns face financial challenges with the proposed Soil Monitoring Law of the European Union, which will require the management of soil contamination, since remediating soil in densely populated towns and cities is challenging.We compared the environmental impact of sulfide ore mining in the urban area of Outokumpu in Finland with that of other European sites, focusing on soil contamination. Soil sampling revealed that mine tailings were historically used in road construction. The threshold values of Cu, Ni, and Zn were exceeded at several points, with the highest Cu content reaching 2733mg/kg. Groundwater and surface water contamination was also evident, mainly due to the lack of a proper protective structure in tailings to prevent acid mine drainage. A preliminary risk assessment suggests health risks from unintentional soil ingestion and dust inhalation. However, the issues in many historical mining towns are more severe if they contain high levels of As or Pb which are more toxic than those of concern in Outokumpu.The historical mining town of Freiberg in Saxony, Germany, has been regulated as a ‘Soil Planning Area’, where limit values have been provided based on land use scenarios. The regional handling and re-use of excavated soil is based on contamination categories, with the tightest restrictions for the areas where the As content exceeds 340mg/kg. We suggest ‘Soil Planning Areas’ to be established in historical mining towns facing similar challenges as a first step to mitigate environmental and health risks with reasonable economic resources.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Arsenic in agricultural soils-water systems: transfer mechanisms, remediation options and recommendations for risk management Fabienne Battaglia-Brunet, Ingo Müller, Celia Jones, Mark Elert, Marina Le Guedard, Jennifer Hellal, Hugues Thouin, Isabel Jordan, Ritta L. Keiski, Jana Pinka, et al.

Chronic exposure to arsenic may be detrimental to health. We investigated the behaviour, remediation and risk management of arsenic in Freiberg, Germany, characterized by past mining activities, and near Verdun in France, where World War I ammunition was destroyed. The main results included: (1) pot experiments using a biologically synthesized adsorbent (sorpP) with spring barley reduced the mobility of arsenic, (2) the Omega-3 Index ecotoxicological tests verified that sorpP reduced the uptake and toxicity of arsenic in plants, (3) reverse osmosis membrane systems provided 99.5% removal efficiency of arsenic from surface water, (4) the sustainability assessment revealed that adsorption and coagulation-filtration processes were the most feasible options for the treatment of surface waters with significant arsenic concentrations, and (5) a model was developed for assessing health risk due to arsenic exposure. Risk management is the main option for extensive areas, while remediation options that directly treat the soil can only be considered in small areas subject to sensitive use. We recommend the risk management procedure developed in Germany for other parts of the world where both geogenic and anthropogenic arsenic is present in agricultural soil and water. Risk management measures have been successful both in Freiberg and in Verdun.

This study assessed in situ stabilization combined with phytoexclusion in practical application on agricultural land contaminated strongly, and spatially heterogeneous, with metals (Cd, Pb, and Zn) and As. Single and combined lime marl and phosphate treatments were consecutively planted with two cultivars each of rape, wheat, and barley differing in trace elements (TE) accumulation. The effects on soil acidity, NH4NO3-soluble, and straw and grain TE concentrations were evaluated. The combined fertilizer treatment most effectively reduced metals mobility, but neither amendment mitigated plant TE status, which correlated more with pseudo-total than NH4NO3-soluble TE in soil. The cultivar choice reduced grain Cd by 39 or 21% in barley or wheat, respectively, simultaneously decreased grain Zn, but conversely affected As uptake in wheat grains. The lack of correlations between grain TE concentrations suggests the potential for breeding cultivars with low Cd and As accumulation without causing Zn malnutrition. The cereals had relatively low yields, particularly on highly polluted areas, and only rape and barley grains unexceptionally suited for animal consumption. Agricultural measures and climatic conditions influenced TE mobility. The cultivars' TE uptake varied less than in greenhouse studies, stressing the importance of field studies for an adequate estimation of phytoexclusion potentials.

Arsenic concentrations in soil and water were examined at the European level via a literature review and data inventory in the first phase of the AgriAs European Water JPI project. Arsenic in soil can be derived from both natural and anthropogenic sources. At the European scale, the distribution of arsenic in agricultural topsoil can mostly be explained by geology. In the next step, the AgriAs project investigated arsenic concentrations in soil and water in two regions: Saxony in Germany and Verdun in France. The results were compared with arsenic data from a geogenic arsenic region around the city of Tampere in Finland. In Saxony, arsenic is partly natural and partly derived from the widespread mining and ore processing activities in the area that have lasted for centuries. Areas contaminated with As were found to cover 970 km(2) in Saxony. The soil baseline for As is only 20-40 mg/kg but the highest concentrations in soil are up to 5000 mg/kg. The large number of investigations in Saxony has given a possibility to evaluate As transfer into plants, fodder and food and to develop guidelines for farmers. In Verdun, arsenic is derived from a former chemical ammunition destruction facility that operated in the interwar period. Today, there are hot spots of As in topsoil with concentrations ranging from 100 to 1000 mg/kg, while the baseline concentration in soil is 18 mg/kg. In the Tampere region, baseline concentrations of As in glacial till forest soils are relatively high (30 mg/kg) over an area of 7400 km(2), with hot spots of 1050 mg/kg in topsoil. However, agricultural soils contain clearly lower As concentrations. In all three regions, As concentrations in surface waters and in groundwater were found to be relatively low, and the As concentration in topsoil could not be linked to irrigation with As-containing water. Fortunately, As transfer from soil into plants via root systems is generally low in aerated soil, but As-containing dust can affect fodder plants. Especially in the Freiberg area of Saxony, As is usually associated with Cd contamination in topsoil, and guidelines for farmers based on Cd concentrations are also a good risk management method for As.

Short rotation coppice (SRC) with metal tolerant plants may attenuate the pollution of excessive elements with potential toxicity in soils, while preserving soil resources and functionality. Here, we investigated effects of 6 years phytomanagement with willow SRC on properties including heavy metal levels, toxicity tested by BioTox, microbial biomass, enzyme activities, and functional gene abundances measured by GeoChip of soils contaminated by As, Cd, Pb and Zn, as compared to the same soils under non-managed mixed grassland representing no intervention treatment (Unt). Though metal total concentrations did not differ by SRC and Unt, SRC soils had lower metal availability and toxicity, higher organic carbon, microbial biomass, phosphatase, urease and protease activities, as compared to Unt soils. Significantly reduced abundances of genes encoding resistances to various metals and antibiotics were observed in SRC, likely attributed to reduced metal selective pressure based on less heavy metal availability and soil toxicity. SRC also significantly reduced abundances of genes involved in nitrogen, phosphorus, and sulfur cycles, possibly due to the willow induced selection. Overall, while the SRC phytomanagement did not reduce the total heavy metal concentrations in soils, it decreased the heavy metal availability and soil toxicity, which in turn led to less metal selective pressure on microbial communities. The SRC phytomanagement also reduced the abundances of nutrient cycling genes from microbial communities, possibly due to intense plant nutrient uptake that depleted soil nitrogen and phosphorus availability, and thus site-specific practices should be considered to improve the soil nutrient supply for phytomanagement plants.

The aim of this study was to monitor changes in leaf spectral reflectance due to phytoaccumulation of trace elements (Cd, Pb, and As) in sunflower mutant (M5 mutant line 38/R4-R6/15-35-190-04-M5) grown in spiked and in situ metal-contaminated potted soils. Reflectance spectra (350–2500 nm) of leaves were collected using portable ASD spectroradiometer, and respective leaves sample were analyzed for total metal contents. The spectral changes were quite noticeable and showed increased visible and decreased NIR reflectance for sunflower grown in soil spiked with 900 mg As kg −1 , and in in situ metal-contaminated soils. These changes also involved a blue - shift feature of red-edge position in the first derivatives spectra, studied vegetation indices and continuum removed absorption features at 495, 680, 970, 1165, 1435, 1780, and 1925 nm wavelength. Correlograms of leaf-metal concentration and reflectance values show highest degrees of overall correlation for visible, near-infrared, and water-sensitive wavelengths. Partial least square and multiple linear regression statistical models (cross-validated), respectively, based on Savitzky–Golay filter first-order derivative spectra and combination of spectral feature such as vegetation indices and band depths yielded good prediction of leaf-metal concentrations.

Multielement-contaminated agricultural land requires the adaptation of agronomic practices to meet legal requirements for safe biomass production. The incorporation of bioenergy plants with, at least, moderate phytoextraction capacity into crop rotations with cereals can affect trace elements (TE) phytoavailability and, simultaneously, constitute economic revenues for farmers outside the food or forage sector. Hence, in a crop rotation pot study sunflower (Helianthus annuus L.), modified for high biomass and TE accumulation by chemical mutagenesis, was compared to winter oilseed rape (Brassica napus L.) as pre-crop. On two agricultural soils with different TE loads, the crops´ potential for phytoextraction and for impacts on TE uptake by subsequent winter wheat (Triticum aestivum L.) was studied. The results showed that rape tolerated high-level mixed contamination with metals (Cd, Pb and Zn) and As more than sunflower. In both soils, labile metals concentration increased and soil acidity remained high following sunflower. Furthermore, enhanced grain As accumulation in subsequent wheat was observed. By contrast, soil acidity and Cd or Zn accumulation of subsequent wheat decreased following rape. In the short term, moderate phytoextraction was superimposed by nutrient use or rhizosphere effects of pre-crops, which should be carefully monitored when designing crop rotations for contaminated land.

In this study, we tested the potential of visible-near infrared (VNIR, 350–2500nm) and mid-infrared spectroscopy (MIR, 2500–15,000nm) for quantification and prediction of soil parameters to support the Saxon Permanent Soil Monitoring Program. As Saxony is characterised by a large variety of soil metal concentrations which can negatively affect essential soil functions, the presented study is strongly focused on the forecast of soil metal contents. As data basis, a total of 203 soil samples of the Saxon Permanent Soil Monitoring Program, collected between 1998 and 2013 at 48 representative locations with respect to soil type, parent material, land use and climate conditions, were used. The chemical analysis provided information regarding total soil organic carbon content (TOC) and pH-value as well as element concentrations (Al, As, Ca, Cu, Fe, K, Mn, Na, Ni, Pb, Zn). VNIR-spectra were collected utilising an ASD FieldSpec Pro FR while an Agilent 4300 Handheld FTIR spectrometer was applied to cover the MIR wavelength region. Spectra pre-processing comprised the application of multi scatter correction (MSC), standard normal variate (SNV), continuum removal (CR) and the first and second derivatives. To model the relationship between soil spectral and chemical properties, and to predict element concentration, the spectra and chemical data were used as input for Partial Least Square Regression (PLSR) models. The definition of training data was realised on Kennard-Stone sampling algorithm and we selected 103 samples for model calibration and 100 samples for model validation. In general, the MIR-spectra and the MSC- and SNV-pre-processing improved the model performance. We obtained promising model results for TOC, Al, Fe, K and Ni with R2-values between 0.70 and 0.88. Moderate results were obtained for Ca (R2=0.61) and Mn (R2=0.43). We conclude that VNIR and MIR spectroscopy has the potential to quickly provide reliable information regarding major soil parameters and metal contents and is thus a promising alternative approach to support soil analysis within the Saxon Permanent Soil Monitoring Program.

The in situ stabilization of multielement-contaminated agricultural soils has limited effectiveness when using common single amendments. This study examined the use of drinking water treatment residues (WTR), based on (hydr)oxides of Fe, Al, or Mn, as a cost-effective solution to optimize the immobilization of metals (Cd, Pb, Zn) and As. Trace elements (TE) bioavailability was assessed under semi-controlled conditions in a pot study cultivating winter wheat (Triticum aestivum L. cv. Tiger) until maturity. An Fe-based WTR and a Mn-based WTR, applied at rates of 0.5 and 1% (m/m), were related to effects of lime marl (LM) application. Additionally, a bioassay with earthworms (Dendrobaena veneta) was conducted. Both bioassays were compared with measurements of NH4NO3-soluble, diffusive gradients in thin film (DGT)-available and soil solution TE concentrations, representing well-established surrogates for mimicking the bioavailable element fractions in soil. The application of the Fe-based WTR reduced As accumulation in vegetative wheat tissues (by up to 75%) and earthworms (by up to 41%), which corresponded with the findings from soil chemical analyses and improved plant growth and earthworm body weight. However, As concentrations in cereal grains were not affected, Cd or Pb accumulation by wheat was not mitigated, and Zn uptake was enhanced. By contrast, the Mn-based WTR effected the greatest reduction in Pb uptake, and lowered Cd transfer to wheat grain (by up to 25%). Neither the NH4NO3-soluble nor DGT-available concentrations matched with Cd and Zn accumulation in plants or earthworms, indicating interferences due to competition for binding sites according to the biotic ligand model. The results obtained in this study suggest that a bioassay with key species prior to field application should be mandatory when designing in situ stabilization options. The application of WTR to an agricultural soil strongly affected TE bioavailability to plants and earthworms. Low application rates tended to improve biomass production of biota. Higher application rates involved risks (e.g., P fixation, TE inputs), and none of the amendments tested could immobilize all targeted elements.

Gentle remediation options (GRO), i.e. in situ stabilisation, (aided) phytoextraction and (aided) phytostabilisation, were implemented at ten European sites contaminated with trace elements (TE) from various anthropogenic sources: mining, atmospheric fallout, landfill leachates, wood preservatives, dredged-sediments, and dumped wastes. To assess the performance of the GRO options, topsoil was collected from each field trial, potted, and cultivated with lettuce (Lactuca sativa L.) for 48days. Shoot dry weight (DW) yield, photosynthesis efficiency and major element and TE concentrations in the soil pore water and lettuce shoots were measured. GRO implementation had a limited effect on TE concentrations in the soil pore water, although use of multivariate Co-inertia Analysis revealed a clear amelioration effect in phytomanaged soils. Phytomanagement increased shoot DW yield at all industrial and mine sites, whereas in agricultural soils improvements were produced in one out of five sites. Photosynthesis efficiency was less sensitive than changes in shoot biomass and did not discriminate changes in soil conditions. Based on lettuce shoot DW yield, compost amendment followed by phytoextraction yielded better results than phytostabilisation; moreover shoot ionome data proved that, depending on initial soil conditions, recurrent compost application may be required to maintain crop production with common shoot nutrient concentrations.

A questionnaire survey was carried out in four European countries to gather end-user's perceptions of using plants from phytotechnologies in combustion and anaerobic digestion (AD). Nine actors of the wood energy sector from France, Germany, and Sweden, and eleven AD platform operators from France, Germany, and Austria were interviewed. Questions related to installation, input materials, performed analyses, phytostabilization, and phytoextraction were asked. Although the majority of respondents did not know phytotechnologies, results suggested that plant biomass from phytomanaged areas could be used in AD and combustion, under certain conditions. As a potential benefit, phytomanaged plants would not compete with plants grown on agricultural lands, contaminated lands being not suitable for agriculture production. Main limitations would be related to additional controls in process' inputs and end-products and installations that might generate additional costs. In most cases, the price of phytotechnologies biomass was mentioned as a driver to potentially use plants from metal-contaminated soils. Plants used in phytostabilization or phytoexclusion were thought to be less risky and, consequently, benefited from a better theoretical acceptance than those issued from phytoextraction. Results were discussed according to national regulations. One issue was related to the regulatory gap concerning the status of the plant biomass produced on contaminated land.

Further details of the GREENLAND project, and downloadable versions of the GREENLAND decision support tool and GRO best practice guidance, can be found at http://www.greenland-project.eu. The authors are grateful for financial support from the European Commission under the Seventh Framework Programme for Research (FP7-KBBE-266124), and thank the wider GREENLAND consortium and project advisory board for their support and input during the development of the DST and GRO best practice guidance.

Gentle remediation options (GROs) are risk management strategies or technologies involving plant (phyto-), fungi (myco-), and/or bacteria-based methods that result in a net gain (or at least no gross reduction) in soil function as well as effective risk management. GRO strategies can be customised along contaminant linkages, and can generate a range of wider economic, environmental and societal benefits in contaminated land management (and in brownfields management more widely). The application of GROs as practical on-site remedial solutions is still limited however, particularly in Europe and at trace element (typically metal and metalloid) contaminated sites. This paper discusses challenges to the practical adoption of GROs in contaminated land management, and outlines the decision support tools and best practice guidance developed in the European Commission FP7-funded GREENLAND project aimed at overcoming these challenges. The GREENLAND guidance promotes a refocus from phytoremediation to wider GROs- or phyto-management based approaches which place realisation of wider benefits at the core of site design, and where gentle remediation technologies can be applied as part of integrated, mixed, site risk management solutions or as part of "holding strategies" for vacant sites. The combination of GROs with renewables, both in terms of biomass generation but also with green technologies such as wind and solar power, can provide a range of economic and other benefits and can potentially support the return of low-level contaminated sites to productive usage, while combining GROs with urban design and landscape architecture, and integrating GRO strategies with sustainable urban drainage systems and community gardens/parkland (particularly for health and leisure benefits), has large potential for triggering GRO application and in realising wider benefits in urban and suburban systems. Quantifying these wider benefits and value (above standard economic returns) will be important in leveraging funding for GRO application and soft site end-use more widely at vacant or underutilized sites.

Visible and near infrared reflectance (VNIR; 350-2500 nm) spectroscopy has greatly been used in soils, especially for studying variability in spectrally active soil components (e.g., organic carbon, clays, and Fe/Al oxides) based on their diagnostic spectral features. In recent years, this technique has also been applied to assess soil metallic ions. In this research, the feasibility of VNIR spectroscopy for determination of soil metals was investigated with two soil data sets: (i) artificially metal-spiked and (ii) in situ metal-contaminated soils. Results showed that reflectance spectra of neither metal-spiked soils with Cd, As, and Pb even at their higher concentrations of 20, 900, and 1200 mg kg(-1), respectively, nor in situ metal-contaminated soils (with concentrations of 30 mg Cd, 3019 mg As, and 5725 mg Pb kg-1 soil) showed any recognized absorption peaks that correspond to soil metal concentrations. We observed variations in reflectance intensity for in situ metal-contaminated soils only, showing higher reflectance across the entire spectrum for strongly and lower for less metal-contaminated soils. A significant correlation was found between surface soil metals' concentrations and continuum removed spectra, while soil metals were also found significantly associated with soil organic matter and total Fe. A partial least square regression with cross-validation approach produced an acceptable prediction of metals (R-2 = 0.58-0.94) for both soil data sets, metal-spiked and in situ metal-contaminated soils. However, high values of root mean square error ruled out practical application of the achieved prediction models.

The last few decades have seen the rise of Gentle soil Remediation Options (GRO), which notably include in situ contaminant stabilization ("inactivation") and plant-based (generally termed "phytoremediation") options. For trace element (TE)-contaminated sites, GRO aim to either decrease their labile pool and/or total content in the soil, thereby reducing related pollutant linkages. Much research has been dedicated to the screening and selection of TE-tolerant plant species and genotypes for application in GRO. However, the number of field trials demonstrating successful GRO remains well below the number of studies carried out at a greenhouse level. The move from greenhouse to field conditions requires incorporating agronomical knowledge into the remediation process and the ecological restoration of ecosystem services. This review summarizes agronomic practices against their demonstrated or potential positive effect on GRO performance, including plant selection, soil management practices, crop rotation, short rotation coppice, intercropping/row cropping, planting methods and plant densities, harvest and fertilization management, pest and weed control and irrigation management. Potentially negative effects of GRO, e.g., the introduction of potentially invasive species, are also discussed. Lessons learnt from long-term European field case sites are given for aiding the choice of appropriate management practices and plant species.

Gentle remediation options (GRO) are risk management strategies/technologies that result in a net gain (or at least no gross reduction) in soil function as well as risk management. They encompass a number of technologies, including the use of plant (phyto-), fungi (myco-), and/or bacteria-based methods, with or without chemical soil additives or amendments, for reducing contaminant transfer to local receptors by in situ stabilization, or extraction, transformation, or degradation of contaminants. Despite offering strong benefits in terms of risk management, deployment costs, and sustainability for a range of site problems, the application of GRO as practical on-site remedial solutions is still in its relative infancy, particularly for metal(loid)-contaminated sites. A key barrier to wider adoption of GRO relates to general uncertainties and lack of stakeholder confidence in (and indeed knowledge of) the feasibility or reliability of GRO as practical risk management solutions. The GREENLAND project has therefore developed a simple and transparent decision support framework for promoting the appropriate use of gentle remediation options and encouraging participation of stakeholders, supplemented by a set of specific design aids for use when GRO appear to be a viable option. The framework is presented as a three phased model or Decision Support Tool (DST), in the form of a Microsoft Excel-based workbook, designed to inform decision-making and options appraisal during the selection of remedial approaches for contaminated sites. The DST acts as a simple decision support and stakeholder engagement tool for the application of GRO, providing a context for GRO application (particularly where soft end-use of remediated land is envisaged), quick reference tables (including an economic cost calculator), and supporting information and technical guidance drawing on practical examples of effective GRO application at trace metal(loid) contaminated sites across Europe. This article introduces the decision support framework. ©2015 Wiley Periodicals, Inc.

This research studied the changes in leaf reflectance spectra (350-2500 nm) due to metal phytoextraction into barley plants grown in metal-spiked soils (3 levels of Cd, Pb, As and their metal-mixture treatments). Growth of barley was adversely affected due to 100 mg As kg(-1) and metal-mixture (10 Cd+ 150 Pb+ 100 As; mg kg(-1)) treatments. Metal phytoextraction were in order of: root > straw >= leaves > grains. Results of reflectance spectra of leaves show the influence of As-treatment only, causing spectral changes in visible and infrared domains mostly, as apparent from the significant correlation between leaf-As and leaf-spectra. Chlorophyll and water stress indices and band depths analyses showed significant correlations to leaf-As, and can be used to distinguish metal-stressed plants. Finally, regression models demonstrate the potential use of hyperspectral reflectance data to monitor plant health during phytoremediation process and to estimate leaf-As in barley, particularly in this study.

During the past decades a number of field trials with gentle remediation options (GRO) have been established on trace element (TE) contaminated sites throughout Europe. Each research group selects different methods to assess the remediation success making it difficult to compare efficacy between various sites and treatments. This study aimed at selecting a minimum risk assessment battery combining chemical and ecotoxicological assays for assessing and comparing the effectiveness of GRO implemented in seven European case studies. Two test batteries were pre-selected; a chemical one for quantifying TE exposure in untreated soils and GRO-managed soils and a biological one for characterizing soil functionality and ecotoxicity. Soil samples from field studies representing one of the main GROs (phytoextraction in Belgium, Sweden, Germany and Switzerland, aided phytoextraction in France, and aided phytostabilization or in situ stabilization/phytoexclusion in Poland, France and Austria) were collected and assessed using the selected test batteries. The best correlations were obtained between NH4NO3-extractable, followed by NaNO3-extractable TE and the ecotoxicological responses. Biometrical parameters and biomarkers of dwarf beans were the most responsive indicators for the soil treatments and changes in soil TE exposures. Plant growth was inhibited at the higher extractable TE concentrations, while plant stress enzyme activities increased with the higher TE extractability. Based on these results, a minimum risk assessment battery to compare/biomonitor the sites phytomanaged by GROs might consist of the NH4NO3 extraction and the bean Plantox test including the stress enzyme activities.