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The reconstruction or regeneration of damaged bone tissue is one of the challenges of orthopedic surgery and tissue engineering. Among all strategies investigated, additive manufacturing by fused deposition modeling (3D-FDM printing) opens the possibility to obtain patient-specific scaffolds with controlled architectures. The present work evaluates in depth 3D direct printing, avoiding the need for a pre-fabricated filament, to obtain bone-related scaffolds from direct mixtures of polylactic acid (PLA) and hydroxyapatite (HA). For it, a systematic physicochemical characterization (SEM-EDS, FT-Raman, XRD, micro-CT and nanoindentation) was performed, using different PLA/HA ratios and percentages of infill. Results prove the versatility of this methodology with an efficient HA incorporation in the 3D-printed scaffolds up to 13 wt.% of the total mass and a uniform distribution of the HA particles in the scaffold at the macro level, both longitudinal and cross sections. Moreover, an exponential distribution of the HA particles from the surface toward the interior of the biocomposite cord (micro level), within the first 80 µm (10% of the entire cord diameter), is also confirmed, providing the scaffold with surface roughness and higher bioavailability. In relation to the pores, they can range in size from 250 to 850 µm and can represent a percentage, in relation to the total volume of the scaffold, from 24% up to 76%. The mechanical properties indicate an increase in Young’s modulus with the HA content of up to ~50%, compared to the scaffolds without HA. Finally, the in vitro evaluation confirms MG63 cell proliferation on the 3D-printed PLA/HA scaffolds after up to 21 days of incubation.

The characteristics of the soil pore network condition the flow of nutrients, liquids, gases, and temperature through this medium. We hypothesized that soil structure properties will also control soil microbial processes. To test this, we selected soil samples where land use generated differences in soil structure. Unaltered soil samples from three adjacent plots were analysed: a potato field soil, ploughed after harvesting, two weeks before sampling (Control); another ploughed potato plot, in which bioaugmentators (plant growth promoting bacteria) had been applied to increase soil biodiversity (Bio); and a third soil, dedicated to melon cultivation, without bioaugmentation, followed by six months of fallow (Melon). In each soil, three different depths were analysed (between 0/-3.33 cm; -3.33/-6.67 cm; and -6.67/-10 cm), and, at each depth, we separated aggregates into three size categories: >0.8 cm, 0.8-0.2 cm, and 0.86) and optical density (r > 0.69), while respiration increased with the number of pores (r > 0.75) and pore length (r > 0.71). The respiration rate within small aggregates (0.2 to 0.8 cm) increased with the length and number of pores (r > 0.84).In conclusion, aggregation seems to have a greater effect on the physical and biological properties of the soil than differences between land uses studied and the depths considered. On the other hand, characteristics such as connectivity, tortuosity, and the length and number of pores seem to regulate both bacterial growth and respiration, while fungal growth appears independent.

InBestSoil (IBS) project has been funded under the call "Incentives and business models for soil health" from the EU Missions program (Horizon Europe) — Grant Agreement n° 1010910990. The University of Vigo leads the project within a consortium of 19 partners from 10 countries with a 48-month duration.The IBS aims to quantify the economic benefits of the different ecosystem services that healthy soils can provide and analyze the costs and benefits of the interventions to improve soil health. This economic valuation will facilitate investments in soil health and the generation of new businesses, incentives, and policies that help us to reclaim degraded soils or improve the quality of existing ones.In IBS, we analyzed nine case studies across Europe with different land uses (agricultural, forestry, urban, and mining) across four different biogeographic regions (Boreal, Continental, Atlantic and Mediterranean). These long-term experiments have been running for years into an established network of stakeholders and businesses created to exploit improved soil quality benefits. In each case study, we will assess the outcome of soil reclamation actions by examining the actual soil quality indicators and comparing them with the antecedent indicators before the restoration process. Then, we will conduct an economic valuation of the soil quality differences by considering the potential income from the enhanced ecosystem services that have proved effective in improving soil quality indicators.To develop a multi-actor approach, we will gather data and opinions from stakeholders about every relevant item in this transformation, i.e., from selecting soil indicators to creating new incentives and policies. These consultations will be done at each step of the project through a collaborative platform developed specifically for the IBS. The IBS partners come from a wide range of sectors (from universities to distribution companies of organic products), allowing us to create an extensive network of stakeholders to share information, feedback experiences, and diffusion of results.With this information, we will first try to scale up by exporting to other areas the business models that were created around our case studies. Second, we will use the information obtained through the economic valuation to develop new business models. Finally, we will try to integrate the information obtained to develop a set of incentive support systems and new policies. Acknowledgments: This study has been funded by the Horizon Europe Project InBestSoil (GA 101091099).

Cephalopod ink is a complex mixture of bioactive substances with technical properties of interest in many fields (e.g., biophysics, ecology, environment, biomedicine, food technology, cosmetics, or fine arts). It was previously reported that organic nanoparticles may naturally appear in this mixture. Thus, the particle size determination of these biopolymers is interesting from the point of view of food nanotechnology and nanotoxicology. In this work, the particle size of purified eumelanin microspheres from commercial sepia ink was successfully measured by three techniques: Scanning electron microscopy (SEM), dynamic light scattering (DLS), and asymmetric-flow field-flow fractionation linked to multi-angle laser-light scattering (AF4-MALLS). This study shows the potential and differences of the application of these techniques in terms of sample preparation, conditioning, introduction, and principles for particle size characterization of natural organic nanoparticles in foods. Thus, this methodology can be a model for the characterization of other natural and engineered organic nanoparticles in this matrix type. DLS and AF4-MALLS provide the size corresponding to the hydrodynamic diameter, which is usually larger than the size of the dense core provided by SEM (without hydration or solvation layer). Additionally, SEM informs about the particles morphology, showing a quasi-spherical shape for particles between 100 and 140 nm. DLS and AF4-MALLS indicate particles of hydrodynamic diameter in the range of 180–260 nm. Furthermore, the absolute molar mass of particles has been measured by MALLS.

We present a method to identify the characteristics of pressure jumps in repeated pump-driven saturation and drainage cycles in packed sand columns, i.e., pore pressure from zero to -80 hPa. This method is based on the registration of pore pressure oscillations using high sensitivity and rapid response tensiometers. The pressure signals were processed to identify and extract the pressure waveforms read by two tensiometers simultaneously. Then, the waveforms were classified by k-means clustering algorithms and principal component analysis. We obtained a classification of different types of pressure waveforms that are consistent throughout successive cycles of wetting and drainage cycles. This consistency can be associated with patterns of fast capillary displacements in macropores, and ultimately, to hydrodynamic features of the structure.

Tunable Resistive Pulse Sensing, TRPS, is an emerging technique used in quantification and measuring the size (particle-by-particle) of viruses, exosomes and engineered colloidal spheres in biological fluids. We study the features of TRPS to enhance size characterization and quantification of submicron-sized microplastics, also called plastic microparticles, MP, in freshwater environments. We report alterations on the detection of the resistive pulses in the TRPS caused by humic acids, HA, during the size measurement of polystyrene microspheres used as MP surrogate. We discuss the alteration of the electric field in the measuring channel of the TRPS apparatus induced by the passage of HA. TRPS is a fast and precise technique for counting and size determination of MP but needs the evaluation of the influence of the organic matter on the current blockades. We show that statistical clustering models of the magnitude distribution of the resistive pulses can help to detect and quantify changes in the pulse size distributions induced by flocculation of humic acids. Conclusions of this study indicate that TRPS can be a valuable tool to improve the knowledge of the MP fate in surface waters, in the vadose zone and groundwater.

Multifractal analysis of pore images obtained from X-ray computed tomography (CT) was used to characterize the scaling properties of macropores in soils with different managements and their correspondence with macroscopic physical properties related with the soil functions. We used CT images of twenty undisturbed soil columns to examine the multifractal properties of the pores identified by X-ray computed tomography (CT-Porosity). Multifractal spectra successfully describe the scaling of the pore network in all soil columns. The dimensions and scaling parameters of these spectra correlate with macroscopic magnitudes, namely, CT-Porosity, surface area of the pore walls, tortuosity, and bulk density. We also found strong correlations between the singularity spectra and the topological descriptors of the pore network skeleton: total slab voxels, number of branches per path, number of endpoints and sum of branch length, among others. These correlations show that the complexity of the CT-Porosity can be related quantitatively with physical properties, the organization of the pore skeleton and solute transport.

The understanding of relations between quantitative information of soil structure from X-ray computed tomography (CT) and soil functions is an important topic in agronomy and soil science. The influence of tillage on macroporosity (i.e., pores measured by CT >240 μm in all directions) could be manifested in their effects on solute and colloid transport properties. Tillage will also have crucial importance on preferential flow; i.e., a direct flow through root and earthworm channels. Increasing knowledge of the relationships between soil tillage, structure, and transport contributes to a deeper insight into the key factors of soil management influencing productivity, environmental quality and crop health. The aim of this work is the identification of relationships between soil management of the pore network and the influence of the characteristics of the paths identified by CT on the transport of solute and colloidal tracers. In this work, we used CT to characterize the macropore network ( >0.24 mm) of sixteen columns (100 height × 84 diameter, mm) of adjacent plots under different soil management as follows: conventional management with shallow tillage after sowing (4 samples), conventional management with no tillage after sowing (4 samples), and organic vegetables (8 samples). The soil samples were installed in columns under a dripper, and the transport behavior was examined during breakthrough of Br− and 1-μm latex microspheres in samples near saturation. Transport of Br− and latex microspheres was modeled using a two-region physical non-equilibrium model (dual porosity). Preferential flow was higher under organic management, although the pore water velocities were, in general, lower. The preferential flow of Br− was correlated with the total volume of macropores extracted from each tomography, and the local increase in the Hounsfield value (i.e., CT matrix density, CTMatrix) surrounding the macropores. The denser lining, produced by the earthworms in the inner walls of the pores, was inversely correlated with the kinetic exchange coefficient between mobile and immobile zones of the dual-porosity model. The macropore roughness indicated by the CT-macropore surface area was correlated with the solute dispersion coefficient and with the solute travel time. Finally, we found that the overall CTMatrix density is inversely related to the preferential flow. The importance of this work lies in the improvement of the accuracy of predictions related to flow and transport through soils, especially those processes that include particles traveling through the soil.

This study provides insights on the significance of network features of soil macropores on the transport of solutes and colloids, and in the filtrating capacity of the soil. We applied percolation theory and network analysis to the pore network extracted from X-ray computed tomography (imaged porosity) in intact columns sampled from topsoils with different tillage treatments. Moreover, we developed a procedure to extract the backbone, which is the part of the percolation cluster that controls the direct flow between two boundaries in near saturated conditions, using the ImageJ open source imaging software. We also calculated the percolation threshold of each soil, the probability at which the soil starts to percolate (for the resolution considered). Some backbone characteristics (pore volume, wall surface, circularity, fractal dimension, number of loops and tortuosity) showed significant differences between the treatments. Tilled conventional and organic with high earthworm activity exhibited more complex backbones than no-till soil. Backbone volume, surface, fractal dimension and number of loops are correlated with the surface area of pore walls stained by fluorescent microspheres (MS) used as a colloidal tracer. We also found significant correlations between the tortuosity and the number of end-points of the backbone and the transport model parameters for the microspheres and bromide. These findings reinforce the phenomenology between transport in porous media and percolation theory. Moreover, the properties based on percolation theory allow a complete characterization of the complex soil structure and the development of more accurate transport models.

The release and transport of active ingredients (AIs) from controlled-release formulations (CRFs) have potential to reduce groundwater pesticide pollution. These formulations have a major effect on the release rate and subsequent transport to groundwater. Therefore the influence of CRFs should be included in modeling non-point source pollution by pesticides. We propose a simplified approach that uses a phase transition equation coupled to the diffusion equation that describes the release rate of AIs from commercial CRFs in porous media; the parameters are as follows: a release coefficient, the solubility of the AI, anddiffusion transport with decay. The model gives acceptable predictions of the pesticides release from commercial CRFs in diffusion cells filled with quartz sand. This approach can be used to study the dynamics of the CRF-porous media interaction. It also could be implemented in fate of agricultural chemical models to include the effect of CRFs.

Discontinuous air–water displacement at the pore scale (from 10 −5to 10 −3m) affects fluid invasion in porous media at the core scale (10 −3to 1 m). Understanding of this effect is essential to upscale flow processes. In this study we used the analysis of pressure jumps to propose an upscaling mechanism. Large pressure jumps occur during drainage in macroporous structured soils; we suggest a hypothesis for their occurrence. Drainage experiments in packed sand and structured soils enclosing large pores showed large jumps (?5-hPa peak pressure). Large jumps resulted from a pressure relaxation process that first initiates from pore-scale air–water displacements and then expands to larger scales. We found that the power-law exponents for the distribution of the size of large jumps found in structured soil are greater than the typical values reported for Haines jumps in packed granular porous media. The difference in the exponent suggests that the magnitude of displacements occurring in structured soil has different scaling factors than in simple media. A mechanism for this change of scale is proposed on the basis of the large contrast between pore throat and matrix in macroporous soil. The mechanism consists of a fast pressure relaxation in the macropores triggered by a break in the capillary shield at the pore throat. These findings contribute to an explanation of the scaling relations of air–water displacements in complex porous media and unveil links between the soil structure and flow of fluids.

Pore water flow velocity can influence the processes involved in the contaminant transport between relative stagnant zones of porous media and their adjacent mobile zones. A particular case of special interest is the occurrence of high flow rates around the controlled release granules containing pesticides buried in soil. The release of the pesticides carbofuran and fenamiphos from commercial controlled release formulations (CRFs) was studied, comparing release tests in a finite volume of water with water flow release tests in saturated packed sand at different seepage velocities. For water release kinetics, the time taken for 50% of the pesticide to be released (T(50)) was 0.64 hours for carbofuran and 1.97 hours for fenamiphos. In general, the release rate was lower in the porous matrix than in the free water tests. The faster release rate for carbofuran was attributed to its higher water diffusivity. The seepage velocity has a strong influence on the pesticide release rate. The dominant release mechanism varies with the progress of release. The evolution of the mechanism is discussed on the basis of the successive steps that involve the moving boundary of the dissolution front of the pesticide inside the granule, the concentration gradient inside the granule and the flow boundary layer resistance to solute diffusion around the granule. The pore water velocity influences the overall release dynamics. Therefore, seepage velocity should be considered in pesticide release to evaluate the risk of pesticide leaching, especially in scenarios with fast infiltration.

The potential effect of phosphate on metal mobility makes an accurate knowledge of the influence of this element on the dynamics of metals in soil highly interesting. Phosphate in agricultural soils can easily interact with zinc as a result of the former being applied at substantial rates to avoid nutritional deficiencies in crops on acid soils and the latter supplied via Zn-containing pesticides and amendments. In this work, we studied the influence of P on the Zn adsorption capacity of eight surface horizons in soils on granite and amphibolite materials. The presence of P, especially at high concentrations, was found to boost Zn adsorption. The effect was more marked in the soils on amphibolite, which contained increased concentrations of Fe and Al oxides relative to those on granite. The increased adsorption of zinc by effect of the presence of phosphate is ascribed primarily to the formation of a P–Zn complex in colloid surfaces.

The adsorption and desorption of zinc in acid soils developed over granite and amphibolite were investigated with and without the simultaneous addition of copper. In stirred flow experiments, the maximum Zn sorption capacity (qmax) ranged from 1.29 to 4.36 mmol kg−1, and was significantly correlated (r = 0.924; p

Understanding the mechanisms behind the transport of particulate contaminants in porous media is crucial with a view to evaluating their potential impact on the environment. Much of the copper used in agriculture is sprayed as colloidal copper oxychloride, and despite its potential environmentally adverse consequences, colloidal transport of particulate formulations of copper remains poorly understood. In this work, transport of copper colloids from a commercial copper oxychloride based fungicide formulation was studied by measuring its breakthrough in saturated quartz sand columns. The influence of ionic strength and flow rate on the test results suggests that retention of copper oxychloride based colloids is governed by weak forces. The particle deposition dynamics of the studied copper formulation was consistent with a two-site kinetic attachment model. The proposed colloid retention mechanisms are highly sensitive to the fungicide particle size. A comparison of our test results with reported data for other copper oxychloride wettable powder fungicide formulations revealed that transport of copper oxychloride is strongly influenced by its particle size. This is consistent with the theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO), but only if binding occurs at the secondary minimum in the potential, where attachment is less favorable with small particles. The influence of particle size is also consistent with the results of previous studies where deposition was ascribed to retention at a secondary minimum. The mobility of colloidal formulations of these copper-based fungicides in saturated porous media increases with increasing particle size.

The agronomic utility of a solid waste, waste bentonite (WB), from wine companies was assessed. In this sense, the natural characteristics of the waste were measured, followed by the monitoring of its effects on the adsorption/desorption behaviour of three quaternary herbicides in acid soils after the addition of increasing levels of waste. This was done with the intention of studying the effect of the added organic matter on their adsorption. The high content in C (294 g kg −1 ), N (28 g kg −1 ), P (584 mg kg −1 ) and K (108 g kg −1 ) of WB turned it into an appropriate amendment to increase soil fertility, solving at the same time its disposal. WB also reduced the potential Cu phytotoxicity due to a change in Cu distribution towards less soluble fractions. The adsorption of the herbicides paraquat, diquat and difenzoquat by acid soils amended with different ratios of WB was measured. In all cases, Langmuir equation was fitted to the data. Paraquat (PQ) and diquat (DQ) were adsorbed and retained more strongly than difenzoquat (DFQ) in the acid soil studied. However, the lowest retention of DFQ in an acid soil can be increased by amendment with organic matter through a solid waste from wineries, and it is enough for duplicate retention a dosage rate of 10 t/ha. Anyway, detritivores ecology can still be affected. Detritivores are the organisms that consume organic material, and in doing so contribute to decomposition and the recycling of nutrients. The term can also be applied to certain bottom-feeders in wet environments, which play a crucial role in benthic ecosystems, forming essential food chains and participating in the nitrogen cycle.

The sorption of copper from copper nitrate solutions by eight acid soils developed over granites or amphibolites was increased significantly by treatment with phosphate. Addition of phosphate did not significantly alter the Z-potentials of the clay fractions of these soils, and the effect of phosphate was not increased by applying it to the soil in advance of the copper solution. These findings suggest that the influence of phosphate on copper sorption was not due to its increasing the electrostatic attraction of Cu2+ ions by soil particles, or to reaction between Cu2+ ions and sorbed phosphate. Rather, MINTEQA2 simulations suggest that the addition of phosphate raised pH, and hence the formation, in solution, of readily sorbed Cu–P species.

The objective of this work was to assess the sorption of copper (Cu) applied as a Cu-oxychloride metalaxyl formulation by soils characterized by anthropogenic accumulation of Cu due to agricultural activity. The methods involved batch incubation of soils with a Cu-oxychloride metalaxy-based fungicide suspended in 0.01 M CaCl(2), phase separation, and determination of the concentration of Cu (Cu) in solution. Results showed that specific soil properties influenced solubilization of the Cu from the fungicide. The amount of dissolved Cu depended on the soil pH, its potential acidity, and its cation exchange capacity. The amount of anthropogenic Cu in the soil had a minor influence on soluble Cu after the addition of the fungicide. Thus, Cu-based antifungal treatment can increase the local concentration of soluble Cu in acid soils but is not likely to affect the [Cu] in moderately acidic or neutral soils.

Copper mobilization from vineyard soils and sediments to waterways can be potentially toxic to aquatic organisms and cause ecosystem degradation, depending on their behavior as a sink or source of Cu. To assess Cu mobilization to waterways, soil (n = 5) and sediment (n = 5) samples from vineyards at different pH levels were used to determine the equilibrium concentration of Cu (ECuC 0 ). Relationships between ECuC 0 and physicochemical properties and Cu fractions of soils and sediments were also determined. Sediments had total Cu content (256-947 mg kg -1 ) greater than did the soils (166-359 mg kg -1 ), with Cu bound to organic matter as the dominant fraction. The ECuC 0 were similar in soils and sediments (

The agronomic utility of a solid waste, waste perlite (WP), from wine companies was assessed. In this sense, the natural characteristics of the waste were measured, followed by the monitoring of its effects on the chemical properties of acid soils and the growth of Lolium multiflorum. Taking into account that heavy metals associated to the waste (such as Cu, Zn and Mn) could cause problems when used as amendment, the changes in their total levels and in their soil fractionation were also studied, together with their total contents in L. multiflorum. The high content in C (214 g kg−1), N (25 g kg−1), P (534 mg kg−1) and K (106 g kg−1) of WP turned it into an appropriate amendment to increase soil fertility, solving at the same time its disposal. WP contributed to increase soil pH (in 2 pH units) and cation exchange capacity (CEC increased in 3 cmolc kg−1 units), but reduced the potential Cu phytotoxicity due to a change in Cu distribution towards less soluble fractions. The growth of L. multiflorum adequately responds to the treatment with WP at addition rates below 2.5 g kg−1, whereas the imbalance between nutrients can justify the reduction in biomass production at higher WP addition rates. The levels of heavy metals analyzed in L. multiflorum biomass (8–85 g kg−1) do not seem to cause undesirable effects on its growth.

This paper concerns copper levels in the components of soils and river sediments in a river basin partially devoted to vineyards that are regularly treated with copper-bearing grapevine fungicides. Copper concentrations were determined in 26 soil samples, 20 river sediment samples and 71 river water samples taken in a small basin with steep slopes suffering significant erosion. Mean total Cu concentration was 31 mg kg − 1 in woodland soils, 30 mg kg − 1 in pasture soils, and eight times higher, 246 mg kg − 1 (range 157–434 mg kg − 1 ), in productive vineyard soils. Total copper concentration in river sediments ranged from 18 to 209 mg kg − 1 depending on the proportion of land under vineyard in the sub-basin drained via the sampling point ( r = 0.915, p Soils differed relatively little as regards the distribution of Cu among various fractions; in particular, about 50% of total copper content was generally bound to soil organic matter. The distribution of Cu in sediments was more heterogeneous: sandy sediments had copper distributions similar to those observed in soils, but in silty sediments with large inorganic colloids fractions it was these amorphous colloids that bound the largest proportion of copper (mean 31.5%). The absence of significant differences among water-soluble Cu concentrations at the various water-sampling points suggests that winegrowing does not increase water-soluble Cu levels in the river under normal circumstances.

The aim of this study was to examine the fate of quaternary herbicides in soil deposits derived from erosion of vineyard-devoted soils. Herbicide occurrence in the crop soils was due to the farmer application inputs. Special attention should be paid to the presence of paraquat (PQ) in the studied vineyard-devoted soils. The major factor governing the sorption of PQ was the solid state organic fraction with the clay mineral content also making a significant contribution. The mobilization and transport of quats-enriched soil particles may generate downslope and downstream environmental problems that mainly affect detritivore ecology.

Pesticides, the most cost-effective means of pest and weed control, allow the maintenance of current yields and so contribute to economic viability. Concern about the environmental impact of repeated pesticide use has prompted research into the environmental fate of these agents, which can emigrate from treated fields to air, other land and waterbodies. How long the pesticide remains in the soil depends on how strongly it is bound by soil components and how readily it is degraded. It also depends on the environmental conditions at the time of application, e.g., soil water content. Pesticide use must ensure public safety and environmental protection with regards to both the chemical itself and their potentially harmful metabolites. This paper reviews what is known of the influence of the physical and chemical characteristics of the soil system, such as moisture content, organic matter and clay contents, and pH, on the sorption/desorption and degradation of pesticides and their access to groundwater and surface waters. An understanding of the fate of pesticides is essential for rational decision-taking regarding their authorization. To reach an adequate understanding will require the concourse of soil science, clay mineralogy, physical chemistry, surface chemistry, environmental microbiology, plant physiology and, no doubt, other disciplines. Only through a multidisciplinary approach to environmental research will it be possible to plan, manage, pursue and integrate the results of the studies that will be necessary for the development of tools and techniques allowing effective environmental decision-making. There seems to be a great potential to develop microbially derived pesticides, which are effective, reliable and have a low environmental risk. In addition, new application techniques, for example precision band spraying, can reduce the dose, which can be a very effective way to minimize transport and emission but also to avoid a build-up of resistance in target organisms. Improved formulations will also be needed to reduce off-target deposition, improve retention on target, and enhance uptake and translocation.

We examined the suitability of the ink of Sepia officinalis as a surrogate for transport studies of microorganisms and microparticles in porous media. Sepia ink is an organic pigment consisted on a suspension of eumelanin, and that has several advantages for its use as a promising material for introducing the frugal-innovation in the fields of public health and environmental research: very low cost, non-toxic, spherical shape, moderate polydispersivity, size near large viruses, non-anomalous electrokinetic behavior, low retention in the soil, and high stability. Electrokinetic determinations and transport experiments in quartz sand columns and soil columns were done with purified suspensions of sepia ink. Influence of ionic strength on the electrophoretic mobility of ink particles showed the typical behavior of polystyrene latex spheres. Breakthrough curve (BTC) and retention profile (RP) in quartz sand columns showed a depth dependent and blocking adsorption model with an increase in adsorption rates with the ionic strength. Partially saturated transport through undisturbed soil showed less retention than in quartz sand, and matrix exclusion was also observed. Quantification of ink in leachate fractions by light absorbance is direct, but quantification in the soil profile with moderate to high organic matter content was rather cumbersome. We concluded that sepia ink is a suitable cheap surrogate for exploring transport of pathogenic viruses, bacteria and particulate contaminants in groundwater, and could be used for developing frugal-innovation related with the assessment of soil and aquifer filtration function, and monitoring of water filtration systems in low-income regions.

The acid soils of Ourense province riverland (Galicia, NW Spain) produce about 50,000 tons of grapes for winemaking. As part of ongoing investigations into fungicide transport in Ourense vineyard soils, the occurrence of several fungicides in such soils was investigated. Soil samples were collected from the inter-row topsoil of a vineyard adjacent to the River Alongos, approximately 15 km SW of the main city of Ourense. The vines were grown in sandy loam with moderate organic carbon (OC) content (1-2%). Fungicide residues were measured in vineyard soils and river sediments by solid-liquid extraction followed by gas chromatography with mass spectrometric detection (GC-MSD). Procymidone and cyprodinil occurred at higher levels in river sediments than in the case of fludioxonil, metalaxyl and penconazole. The highest concentrations of procymidone in sediments were still low (29-57 microg/kg or ppb) suggesting that no accumulation of these compounds occur. All of them were found at higher concentrations in soil; maxima concentrations were about 1000 microg/kg for procymidone and metalaxyl, and about 400 microg/kg for cyprodinil, fludioxonil and penconazole. Folpet was never detected (detection limit lower than 2 microg/kg) in soil and sediments, suggesting that this fungicide was unstable in such samples. The frequency of fungicide detections in soils can be related to their applications in vineyards and the effect of washing off through vineyard canopy by rainfalls. The results found suggest that the vineyard soils of this region are unlikely to be prone to transport of fungicides, and therefore water supplies in this area are unlikely to be at any significant risk of contamination through viticultural use of these compounds.

We studied total Cu content and its distribution in 33 surface soil samples cultivated with vines for variable lengths of time in the Monterrei designation of origin (DO), located in Galicia (NW Spain). The study was focused on the influence of land use changes on soil degradation by effect of Cu accumulation and availability. Total copper concentration in soils ranged from 25 to 272 mg kg−1. The time during which each soil was cultivated with vines was found to affect both the total concentration of copper and its distribution. The average concentration of copper in young vineyards was 64 mg kg−1, whereas those in old and abandoned vineyards were 100 and 132 mg kg−1, respectively. Copper bound to organic matter and to amorphous inorganic colloids were greater in old and abandoned vineyards, where they accounted for 51 and 52 per cent, respectively, of total copper, than in young vineyards (39 per cent). Copper bound to crystalline Al and Fe colloids accounted for 21, 22 and 12 per cent of total Cu in old, abandoned and young vineyards respectively. The prevalence of Cu bound to the organic fraction reduces the adverse environmental effects of this metal on soil organisms and plants. However, some management practices such as organic matter addition or liming should be implemented in order to delay or avoid soil degradation in young vineyards. For abandoned vineyards, the influence of new land uses on potential Cu mobilisation necessitates careful examination. Copyright © 2007 John Wiley & Sons, Ltd.

When used to fine wines, bentonite acquires a protein load that makes it a potentially useful fertilizer. Other properties of bentonite are also potentially useful for soil amendment. In the work described in this paper, waste bentonite from a winery was applied to an acid soil, and its effects on soil properties and on the growth of Lolium multiflorum were evaluated. Soil N, K, and P contents all increased, as did pH and cation exchange capacity. Biomass production increased as the dose of bentonite increased up to 5 g kg(-1), decreasing at larger doses (possibly as a result of falling potassium/magnesium ratio and increasing electrical conductivity). Environmental drawbacks of waste bentonite include its high soluble copper content, although its conversion in the soil to less soluble forms reduces its potential phytotoxicity. The copper, manganese, and zinc contents of the ryegrass crop were low.

Residual levels and degradation rates of tebuconazole and dichlofluanid in lettuce plants grown in a greenhouse under agricultural conditions typical of northwestern Spain were studied. Lettuce plants were sprayed four times with a homogeneous 0.2% aqueous solution of Folicur Combi (wettable powder containing 40% dichlofluanid and 10% tebuconazole) at a rate of 2500 g/ha. Samples were collected 1, 5, and 9 days after the first two applications and at times ranging from 1 to 27 days after the last two applications. All samples were stored in a refrigerator at 4 degrees C. Fungicide levels were determined by solid-liquid extraction (SLE) followed by gas chromatography and mass spectrometry detection (GC-MSD). Recovery was good for tebuconazole (98%) but low for dichlofluanid (29%); precision was good (10% for both analytes), and quantification limits were low (1.5 mg/kg). Seven days after the last application, dichlofluanid levels were below the maximum allowed limit established in Spain (10 mg/kg), but tebuconazole levels were above the corresponding limit (5 mg/kg). Tebuconazole concentration dynamics was accurately fitted by zeroth- or combined first- and zeroth-order models (depending on variety), but modeling of the behavior of dichlofluanid was less satisfactory, probably due to its instability.

Searching for cheap systems able to contribute to the removal of pollutants from wastewaters, we considered the possibility of using vegetative filter strips and bare soil. The effectiveness of vegetative filter strips for water purification is reviewed in this report. Different studies have shown the efficacy of vegetated buffer strips in removing contaminants from various kinds of wastewater (particularly wastewater derived from farming activities or non-point-sources of pollution), while soil column experiments have shown that pollutant concentrations can be attenuated in part by the soil itself. In view of these findings, we propose investigation of a system based on the depollution power of the combined soil plus vegetation system.

This article describes the influence of dissolved copper on the electrokinetic properties and transport of a copper oxychloride-based fungicide (COF) in porous media. The Zeta potential (ζ) of COF particles increases (viz. becomes less negative) with increasing concentration of Cu2+ in the bulk solution. ζ decreases for COF when the electrolyte (NaNO3) concentration is raised from 1 to 10 mM. This can be ascribed to ion correlation of Cu2+ in the electrical double layer (EDL). COF transport tests in quartz sand columns showed the addition of Cu2+ to the bulk solution to result in increased retention of the metal. Modelling particle deposition dynamics provided results consistent with kinetic attachment. Based on the effect of soluble Cu on colloid mobility, the transport of particulate and soluble forms of copper is coupled via the chemistry of pore water and colloid interactions. Mutual effects between cations and colloids should thus be considered when determining the environmental fate of particulate and soluble forms of copper in soil and groundwater (especially at copper-contaminated sites).

Foliar runoff is one of the most important processes affecting off-target movement of fungicides. In this way, Ridomil® Gold Plus and Ridomil® Gold MZ are two types of wettable powder technical formulations which contain metalaxyl and they are used for such a purpose. A method for quantitative determination of metalaxyl in pesticide formulas has been developed, validated, and subsequently applied to Ridomil® Gold Plus and Ridomil® Gold MZ. The method employs liquid–liquid extraction followed by liquid chromatography coupled with UV detection (LC–UV), using gas chromatography coupled with mass spectrometry as confirmation technique and to carry out a screening of organic adjuvants of these two selected pesticide formulas. Metalaxyl of 26.5 and 41 g/kg was detected in Ridomil® Gold Plus and Ridomil® Gold MZ, close to the manufacture specified level of 25 and 40 g/kg, respectively. Activator and utility adjuvants were detected in these two wettable powder technical formulations. Only methyl-ester-based surfactants were found within the group of nonionic surfactants, but the long-term fates of most adjuvants in soils and elsewhere in the environment are largely unknown, partially because of the lack of long-term monitoring data.

Foliar washoff causes a loss of copper-based pesticides sprayed on crops, leading to an increase in the number of applications and contamination of the soil with Cu. In field studies, the variables that determine the amount of Cu loss are difficult to control. An experimental setup based on a rotating shear device (RSD) was used to estimate the influence of physical factors in the loss of Cu due to washoff of three copper-based fungicides: copper oxychlorhide (CO), Bordeaux mixture (BM), and a mixture of copper oxychlorhide and propylene glycol (CO-PG). Full factorial designs were used to model the loss of Cu from fungicides sprayed on the polypropylene surface of the RSD. Variables in the experiments were rotation speed, wash water volume, and fungicide dose. Good reproducibility was obtained for Cu loss, with a coefficient of variation less than 8%. Mean Cu losses were 27.0, 33.0, and 13.5% of the copper applied in fungicide for the BM, CO, and CO-PG, respectively. Empirical equations were obtained to calculate Cu losses from the rotation speed, wash water volume, and dose, as well as their interactions. CO losses were consistent with a model of particle detachment in which such losses depended on a threshold boundary shear stress required to initiate particle motion. Also, percent CO losses were found to be significantly correlated with the linear momentum at the surface boundary. The momentum values obtained in the RSD tests were similar to those estimated for a rainfall event of 20 mm h(-1) lasting 10 min. The most important mechanism in the loss of CO was the erosion of Cu-bearing particles.

We studied competitive and noncompetitive adsorption of copper and zinc in four acid soils, and compared the behavior of the two metals in untreated samples and samples treated with hydrogen peroxide to remove organic matter in the soil. Copper exhibited stronger competitive adsorption than zinc in the untreated samples. However, removal of organic matter reduced copper adsorption to a greater extent than zinc adsorption, the two metals exhibiting a more similar adsorption pattern than the untreated samples. The presence of copper dramatically reduced zinc competitive adsorption in untreated samples; on the other hand, that of zinc only resulted in slightly reduced competitive adsorption of copper. The hydrogen peroxide treatment decreased competitive adsorption in both metals; however, copper continued to be more efficient than zinc in competing for binding sites on adsorbing surfaces. Desorption of Cu occurred much less readily than desorption of Zn and hysteresis is apparent especially for Cu.

Retention of the cationic herbicides paraquat (PQ), diquat (DQ), and difenzoquat (DFQ) in two vineyard soils with a different management history and retention capacity was examined. The influence of copper on the ability of the soils to retain the herbicides was determined by comparing the results of adsorption and desorption tests on untreated and Cu-enriched soil samples, and also on soils that were previously treated with EDTA to extract native copper. The three herbicides were strongly adsorbed by both soils. Soil 1 exhibited linear adsorption isotherms for PQ and DFQ with partition coefficients, KD, of 1.28 x 103 and 1.37 x 103 L kg-1, respectively, and a Freundlich-type isotherm for DQ with a linearized partition coefficient, KD*, of 1.01 x 103 L kg-1. On the other hand, soil 2 exhibited curved isotherms and smaller KD* values (viz. 106, 418, and 28 L kg-1 for PQ, DQ, and DFQ, respectively). Using EDTA to extract copper from the soils released new sites for the herbicides to bind. The three herbicides exhibited strong hysteresis in the adsorption-desorption process. Extracting copper decreased the percent desorption of PQ and DQ; on the other hand, it decreased the affinity of DFQ for the resulting vacant adsorption sites. Similarly, competitive adsorption tests with copper and the herbicides revealed that the metal was only capable of displacing DFQ from adsorption sites. The behavior of this herbicide in the soils was consistent with a specific adsorption model. The disparate behavior of the two soils toward the herbicides was a result of the adsorption sites in soil 1 being less extensively occupied than those of soil 2 in the adsorption tests. The effect of copper on the adsorption of DFQ in the two soils was acceptably reproduced by an adsorption model involving Coulombic and specific sorption with competition from the metal.

This study investigated the behavior of pesticides commonly used on potato in a part of northwestern Spain with a large area devoted to this crop. Experimental potato plots were treated with commercial formulations of two insecticides, a nematicide, a herbicide, and a combination of two fungicides, and the concentrations of the active ingredients were monitored throughout the growing season in the 0-1 and 1-15 cm soil layers, in water dripping off the potato plants, and in the potatoes themselves. The technique used for pesticide determination was gas chromatography with mass selective detection. For potato analyses, pesticide extraction was optimized. The only pesticide ever detected in potato tubers was metalaxyl, the concentration of which never exceeded half the maximum residual limit even when it was applied several times more often than is officially recommended for potato crops. Metalaxyl was also the only pesticide detected in wash-off, apparently due to its being more soluble in water than the other pesticides applied to the growing plants. A mathematical model of pesticide transport in soil was fitted to the experimental data using the program HYDRUS-1D.

Endosulfan is a potentially harmful, degradation resistant pesticide that is found in soils where it has been used. Despite being hydrophobic and having high affinity for soil matrix components, it has also been found in groundwater. To investigate this behavior, we studied the passage of a commercial emulsified formulation through a column of aggregated vineyard soil under simulated light rain. Breakthrough data were obtained using gas chromatography with electron capture detection to determine the concentration of endosulfan in samples extracted from the column periodically at several depths. These data, and analogous data obtained previously for the passage of bromide, were analyzed using the program CXTFIT v.2. Analysis of the bromide data strongly suggested the existence of preferential flow paths in the column. The endosulfan data were adequately accounted for by a model in which the preferential flow and nonpreferential flow regions are almost isolated from each other. These regions differ also as regards both the partition of endosulfan between soil and soil solution and the rate at which reversibly adsorbed endosulfan is transformed into irreversibly adsorbed endosulfan. The "irreversibility" sink term accounts also for biological and chemical degradation of endosulfan. The findings imply that soil humidity favors the transport of commercial endosulfan by the formation and maintenance of preferential flow paths in soil, controlling both the presence of endosulfan in groundwater and its high persistence in soil.