High Organic Matter Content Research Articles

Anthropogenic soil as an environmental material, as exemplified with improved growth of rice seedlings

Herein, the feasibility of artificial black soil (ABS) derived from hydrothermal humification-hydrothermal carbonization (HTH-HTC) for restructuration of weak soil was verified. This study breaks through the long history of soil formation and evolution, and obtains reconstructed anthropogenic soil (AS) system which only takes one month, for the further application of rice seedlings. HTH-HTC derived by-products are slightly acidic, which facilitates the effective nutrient uptake and prevention of wilt diseases for acid-loving rice seedlings. AS mainly consists of the inherent components retained from weak soil such as SiO2 and minerals, and exogenous components such as artificial humic substances and hydrochar, as introduced by hydrothermal humification processes. Results exhibit that AS has high contents of ammonium nitrogen, organic matter, organic carbon, and abundant porous structure for nutrient transport and water holding, especially, the community diversity and richness of microbial system gets the expected recovery and new beneficial bacteria (such as Caballeronia calidae) or fungi (such as Humicola) appear. Positive effects of AS on agronomic traits in rice seedlings are quantified. As a general result, this study supports the application of AS in sustainable agriculture, and provides a novel strategy to tackle the already-omnipresent land degradation by anthropogenic misuse and larger scale accidents.

Ultrafiltration of anaerobically digested sludge centrate as key process for a further nitrogen recovery process

In a wastewater treatment plant, the centrate generated in the dehydration process of the anaerobically digested sludge has a high potential for nutrients recovery because of its high nutrients concentration (specifically nitrogen and phosphorous). However, the high organic matter and solids content may make difficult its management. Membrane fouling is the most significant challenge limiting the application of membrane techniques for wastewater treatment. Results in this article highlight the potential of conventional filtration followed by ultrafiltration as pretreatment for further nutrients recovery using emerging membrane technologies (as membrane contactor, membrane distillation or forward osmosis). Thus, a conventional filtration (with 1, 5 and 60 μm filters) followed by an ultrafiltration process were tested. The UF membranes studied were two PES membranes (5kDa and 0.01 μm) and one PVDF membranes (100kDa). Results demonstrated that a conventional filtration with a cartridge filter of 60 μm and a subsequent UF process with a 0.01 μm RAY100 membrane (Orelis, France) achieved the best results in terms of the maximum organic matter (66% COD removal) and solids (over 97% suspended solids removal) separation, hardly varying nutrients concentration (13% NH4+ removal). Concerning membrane fouling, FESEM-EDX confirmed salt precipitation on the membrane surface, which has to be controlled to avoid loss of performance.

Organic Matter Enrichment in Basin Periphery: A Case Study of Wufeng-Longmaxi shale, Marcellus shale, and Ohio shale

Our study investigates organic matter(OM) enrichment at the peripheries of marine basins, contrasting with prior research focused on central regions. We analyze three shale formations at three distinct deposition sites: the Marcellus (M) shale near an orogenic belt, and the Wufeng–Longmaxi (WL) shale, the Ohio (O) shale adjacent to a forebulge uplift. By examining factors such as redox conditions, clastic input, paleoproductivity, sedimentary facies and geological activities, we identify that the OM enrichment in shale (M shale) near the orogen resulted from significant inputs of river detritus and semi-deep shelf environment. Additionally, local enrichment is primarily influenced by volcanic ash sedimentation. The shale (O shale) at the distal end of the forebulge shows high OM concentration due to its stable deep-water shelf environment. Local enrichment in this area is caused by sediment re-sedimentation and glaciation. Similarly, the shale (WL shale) at the proximal end also exhibits a high OM concentration due to its stable deep-water shelf environment. In this case, volcanic ash deposition and transgression are responsible for the local enrichment. Our findings reveal how palaeogeography and geological activities impact OM enrichment in basin peripheries, while also offering insights into evaluating shale gas reservoirs.

Nutrient and sediment retention by riparian vegetated buffer strips: Impacts of buffer length, vegetation type, and season

Farming activities in watersheds can significantly increase sediment and nutrient loads, threatening aquatic ecosystems. Riparian vegetated buffer strips (RVBS) have emerged as a promising strategy to capture and sequester these pollutants. While previous research highlights the effectiveness of woody vegetation in reducing nutrient loads, an essential knowledge gap exists regarding the comparative efficiency of different vegetation types (woody, shrubs and grasses) in trapping nutrients and reducing transport from watersheds to waterbodies. To address this knowledge gap, a multi-year field investigation was carried out with the following objectives: (a) to evaluate the influences of RVBS length (2, 5, 10, 14 and 18 m) and vegetation type (woody, grass, shrub, and no buffer) on reducing nutrient and sediment concentrations in surface runoff across different seasons, and (b) to compare soil microbiological characteristics among the different buffer treatments. The findings reveal significant insights into the effectiveness of different RVBS configurations in mitigating nutrient and sediment concentrations. Woody RVBS demonstrated exceptional resilience, particularly during snowmelt periods, significantly outperforming non-woody vegetation types. In contrast, RVBS with grasses often showed limited effectiveness in reducing nutrient levels in overland flow. Importantly, the results highlight the remarkable capacity of woody vegetation within 18-metre RVBS, exhibiting 100% sediment trapping efficiency (STE), 89.8% total nitrogen (TN) removal, and 92.82% total phosphorus (TP) removal. Comparatively, grass treatments displayed lower efficiencies (STE:86%, TN:72.3%, TP: 77.8%), followed by shrubs (STE: 62%, 43.9% and 48.8%), and the control with no buffer (STE: 27%, TN: 20.6%, TP: 23.17%). The superior efficacy of woody vegetation can be attributed to its deep rooting systems and higher organic matter content in the soil compared to grass and shrub areas. Additionally, woody treatments exhibited higher levels of organic carbon, nutrients, and microbial activities in the soil, indicating greater potential for nutrient cycling. High-throughput sequencing revealed shifts in bacterial community diversity and biomass in vegetation treatments compared to the control bare soil. These findings underscore the potential of RVBS incorporating woody vegetation or grass to mitigate nutrient and sediment concentrations by enhancing infiltration and plant uptake processes. Nevertheless, RVBS effectiveness may vary, particularly during snowmelt periods. Future studies should explore RVBS design and management approaches in natural systems, with a specific focus on optimizing the effectiveness of grass treatments during snowmelt.

Predicting Soil Organic Matter, Available Nitrogen, Available Phosphorus and Available Potassium in a Black Soil Using a Nearby Hyperspectral Sensor System.

Black soils, which play an important role in agricultural production and food security, are well known for their relatively high content of soil organic matter (SOM). SOM has a significant impact on the sustainability of farmland and provides nutrients for plants. Hyperspectral imaging (HSI) in the visible and near-infrared region has shown the potential to detect soil nutrient levels in the laboratory. However, using portable spectrometers directly in the field remains challenging due to variations in soil moisture (SM). The current study used spectral data captured by a handheld spectrometer outdoors to predict SOM, available nitrogen (AN), available phosphorus (AP) and available potassium (AK) with different SM levels. Partial least squares regression (PLSR) models were established to compare the predictive performance of air-dried soil samples with SMs around 20%, 30% and 40%. The results showed that the model established using dry sample data had the best performance (RMSE = 4.47 g/kg) for the prediction of SOM, followed by AN (RMSE = 20.92 mg/kg) and AK (RMSE = 22.67 mg/kg). The AP was better predicted by the model based on 30% SM (RMSE = 8.04 mg/kg). In general, model performance deteriorated with an increase in SM, except for the case of AP. Feature wavelengths for predicting four kinds of soil properties were recommended based on variable importance in the projection (VIP), which offered useful guidance for the development of portable hyperspectral sensors based on discrete wavebands to reduce cost and save time for on-site data collection.

Features of the microbial biological “Flavobacterin” impact on the yield and quality of potato tubers of the Udacha variety

Relevance. Organic production is focused on maximizing the use of natural resources. Particular importance is attached to natural nitrogen fixation. Nitrogen fixation provides agricultural systems with nitrogen fixed from the atmosphere and converted into forms accessible to plants. The microbial biological “Flavobacterin”, which exhibits nitrogen-fixing activity and also suppresses a wide range of phytopathogenic fungi and bacteria, was created at the All-Russian Institute of Agricultural Microbiology.Methods. Field studies of the “Flavobacterin” effects on potatoes were carried out from 2018 to 2022 in an organic crop rotation located at the Experimental Station of the Institute for Engineering and Environmental Problems in Agricultural Production Branch of FSAC VIM.Results. The soil of the experimental plot is soddy-podzolic, light loamy gleyic on residual carbonate moraine loam, characterized by a slightly acidic reaction and a high content of organic matter. Udacha variety potatoes were cultivated. The studies were carried out with organic fertilizer — BIAGUM compost, prepared from chicken manure by industrial method. Potato tubers were treated with a “Flavobacterin” when planting, and then on the leaves. Weather conditions in summer during the years of research differed significantly from each other. In all years of the study, with the exception of the dry year 2021, the application of “Flavobacterin” significantly increased potato productivity by an average of 4.4 t/ha, without compost. In the same years, the use of compost together with “Flavobacterin” increased potato productivity by an average of 2.6 t/ha compared to options where compost was used without biological.

Environmental significance of the interaction between titanium dioxides and soil solutions

Nanotechnology, especially in the field of photocatalysis, has witnessed rapid advancements, with titanium dioxide being one of the most widely used photocatalysts. As the use of products containing photoactive nanomaterials increases, concerns have arisen regarding their potential release into the environment over time. This release can impact soil, groundwater, and surrounding ecosystems, resulting in nanoparticles being dispersed in water and eventually depleted from the system. This study aimed to investigate how different soil solutions affect the structural, textural properties, and photocatalytic activity of titanium dioxide-based, commercial reference Evonik Aeroxide P25. The Regosol soil solution, characterized by acidic pH, low ionic content, and high organic matter content, induced nanoparticle aggregation and bandgap changes. In addition, the acidic pH hindered the adsorption process, potentially affecting the photocatalytic processes. In contrast, the Chernozem soil solution, with slightly alkaline pH, high ionic content, and low organic matter content, did not significantly alter the morphology or structure of the material. However, various organic compounds were absorbed on the surface, reducing the availability of active sites. The study highlights the importance of understanding the influence of soil solutions on nanomaterials, as it impacts their properties and environmental risks. Results show that the material is still activated, i.e., it can exert its photoactive effect on the environment. This sheds light on the challenges posed by nanoparticles in soil, particularly in terms of their toxicity and consequences for the surrounding ecosystems. The study underlines the need for further research in this area to assess potential risks and optimise the use of nanomaterials in environmental remediation.

The Use of Products from Leonardite to Improve Soil Quality in Condition of Climate Change

Abstract The principle of sustainable fertilisation in modern agriculture, which ensures that the soil is maintained in a fertile state requires the search for alternatives to manure fertilisation for products based on humic substances to increase the organic matter content of soils.The advantage of leonardite over conventional natural and organic fertilisers is mainly due to its high content of organic matter and humic substances (humic and fulvic acids). Leonardite, due to the presence of humic acids in it, can be suitable for soil amendment and yield of barley. In the conducted studies, the yield increase after adding Rosahumus fertilizer to the soil at a rate of 6 kg.ha−1 + NPK (Nitrogen, Phosphorus, Potasssium) was found to be 11% compared to the control (NPK).There were no changes in the Corg. content of the soil as a result of the application of Rosahumus fertilizer with NPK. The fertilizer only slightly modified the fractional composition of humus. In the future, we should expect an increase in the use of leonardite-derived humic substances in fertilizers and soil conditioners to stabilize soil organic matter.

Schoenoplectus americanus as a potential phytoremediator: in vitro assessment of its ability to remove contaminants in domestic and tannery wastewater

ABSTRACT Growing industrialization and urbanization have led to increased water pollution due to the inadequate treatment and disposal of domestic wastewater (DW) and wastewater produced by industries such as tanneries (TW). These wastewaters are characterized by high concentrations of organic matter, nutrients, sulphates, chlorides and high microbial load. TW also contains phenols and chromium, which disturb and harm the ecosystem the local. The decontamination of wastewater prior to their discharge through biological tools, especially the use of species that are native to the site in need of treatment, has been described as effective and advantageous. This study evaluated the ability of Schoenoplectus americanus, a native plant species from Cordoba (Argentina), to phytoremediate local DW and TW samples at a laboratory scale. The aim was to ascertain whether this system could potentially be considered for the remediation of wastewater in real-world scenarios. S. americanus was able to tolerate pure DW and a 1/20 (v/v) dilution of TW for 30 days under hydroponic conditions. Removal rates ranging from 50% to 89% were obtained for residual organic matter (determined as chemical oxygen demand or COD), total nitrogen (TN) and total phosphorus (TP). Significant removal of total chromium (TCr) and total phenols (TPhs) was also observed in TW (85% and 98%). The number of total coliforms (TC), was reduced by about 96% and 99%. These results indicate that S. americanus is a good candidate for the phytoremediation of regional DW and TW. For this reason, it may be considered for full-scale applications in the future.

Biohydrogen, Volatile Fatty Acids, and Biomethane from Mezcal Vinasses—A Dark Fermentation Process Evaluation

Mezcal is a drink made in Mexico, the production of which generates vinasses with a high content of organic matter (OM) that is not utilized. However, these residues have the potential to be drawn upon in dark fermentation (DF) processes to obtain biogas rich in biohydrogen, biomethane, and volatile fatty acids (VFAs) with the potential to become biofuels. In the present work, the effect of reaction time (RT) and organic load (OL) was assessed based on the efficiency of removing OM, the production of VFAs, and the generation and composition of biogas in a process of DF fed with mezcal vinasses. The results show that increasing the RT and decreasing the OL increases COD removal but decreases biohydrogen production. The maximum production of H2 (64 ± 21 NmL H2/Lreactor) was obtained with the lowest RT (1 d) and the highest OL (13.5 gCODm3d−1), while the highest accumulation of VFAs (2007 ± 327 mg VFA/L) was obtained with an RT of 3 d. It was determined that RT and OL are key parameters in DF processes for biohydrogen and VFA production.

Influence of soil properties on grape and must quality in the Montilla − Moriles protected designation of origin (southern Spain)

There is a growing interest among consumers in some world regions in high-quality products including wine. In this work, we examined the unique quality wines obtained in the Montilla − Moriles wine Protected Designation of Origin (PDO) (Córdoba, southern Spain). Specifically, we assessed the influence of soil properties on the production and quality of Pedro Ximénez grapes in the Montilla − Moriles PDO terroir in six vineyards typical of three different production areas, namely: Sierra de Montilla and Moriles Altos (two premium-grade areas), on soils known as “albariza”, characterized by their parent material (mainly marls and limestones), with a high calcium carbonate content and low organic matter content; and one standard-grade area (Ruedos), with soils developed on varied materials including Miocene marls, which are steeply and highly eroded. Representative soil profiles were evaluated and a field experiment to conducted to obtain data on grape production and quality over a period of three years in the six vineyards. Wine quality in the premium-grade areas was strongly influenced by physical characteristics of the vineyards (altitude and age), and also by some soil properties (limestone, poorly crystalline Fe oxides, and available P, Zn and Cu), production-related characteristics (leaf surface area exposed to solar radiation) and oenological variables (tartaric acid content). By contrast, quality in the standard-grade area was more closely related to soil sand and available Mn, and also to scarcely available P and Zn; however, grape bunches were more abundant and grapes larger (100-berry weight) in this area, and the must produced was richer in malic acid. These results suggest that soil properties in each premium-grade area of the Montilla-Moriles PDO (viz., Sierra de Montilla and Moriles Altos) set them apart from each other and distinguish them from the standard-grade area (Ruedos). Such soil properties are associated to consumer-appreciated quality-related parameters.

Classification and Identification of Pinecone Mulching in Blueberry Cultivation Based on Crop Leaf Characteristics and Hyperspectral Data

While crushed pinecone mulch holds promise as a beneficial material for blueberry cultivation, research on its effectiveness remains limited. Crop leaf characteristics can serve as parameters for assessing mulching effects, although there are several limitations, including the need to analyze various distinct characteristics separately. The combination of hyperspectral data and machine learning techniques is expected to enable the selection of only the most important features among these characteristics. In this study, we investigated the impact of various mulching treatments utilizing pine tree byproducts, including crushed pinecones. Mulching variations included non-mulching (NM), crushed pinecones (PCs), a mixture of crushed pinecones and sulfur (PCS), pine needles (PNs), and sulfur treatment (S). Conventional methods were employed to measure leaf growth (length and width) and physiological characteristics (chlorophyll content, chlorophyll fluorescence, and stomatal conductance). Hyperspectral reflectance was also measured, and classification models using Partial Least Squares Discriminant Analysis (PLS-DA) and eXtreme Gradient Boosting (XGBoost) were developed for crop characteristics, vegetation indices (VIs), visible and near-infrared (VNIR), and short-wave infrared (SWIR). The results showed that using crushed pinecones as the sole mulching material for blueberries, without sulfur treatment, had a positive impact on blueberry growth. The PC treatment exhibited a dual effect on plant growth by lowering the soil pH to 5.89 and maintaining soil moisture within the range of 26.33–35.20%. We observed distinct differences in soil inorganic nutrient content, with higher concentrations of organic matter, total nitrogen, and available P2O5 and K⁺, which positively influenced blueberry growth. Mulching treatments demonstrated superior physiological characteristics, with two classification models identifying stomatal conductance (gs) as a key parameter influencing treatment classification (VIP scores > 1 rank: 3, variable score rank: 1). The photochemical reflectance index (PRI) emerged as a major parameter among VIs, showing potential for measuring water stress (VIP scores > 1 rank: 2, variable score rank: 1). In the SWIR PLS-DA model, wavelength peaks were mainly observed in the O-H overtone (1410 nm, 1450 nm, 1930 nm, 1940 nm, and 2100 nm). Overall, crushed pinecones were found to positively impact the initial growth of blueberries by enhancing water status (plant respiration).

STRUCTURAL-FACIES TYPIZATIONS OF YHE BAZHENOV HIGH-CARBON FORMATION OF THE WEST SIBERIAN BASIN

The Bazhenov high-carbon formation is a part of the Bazhenov formation, characterized by a high content of aquagenic organic matter. Formation is a perspective source for expanding the hydrocarbon resource base. The article presents a combination of the results of core studies, interpretation of well logging and seismic data. A multi-faceted approach to the study of rocks made it possible to divide the West Siberian basin into 13 structur- al-facies zones, each of which has its own structural features of the bazhenov high-carbon formation section. This typification of the section will make it possible in the future to simplify the modeling of the properties of bazhenov high-carbon formation and predicting the most prospective areas.

Treatment of hospital wastewater using aerobic granular sludge technology: Removal performance and microbial dynamics

Hospital wastewater contains several contaminants of emerging concern that cannot be removed by conventional treatment processes. Many of these emerging contaminants are pharmaceutical compounds, which are found in hospital wastewater at high loads. The presence of these toxics affects to the performance of biological processes in receiving wastewater treatment plants. This research evaluated the capability of the aerobic granular sludge technology to remove pharmaceutical compounds from hospital wastewater in a single chamber, which to date has not been investigated with real hospital wastewater. Despite the high non-biodegradable organic matter content, COD and BOD5 removal reached 75 % and 100 %, respectively. Nitrogen removal ranged from 70 %–90 %, and phosphate removal was maximum 50 %. The technology was able to efficiently remove antibiotics, antiepileptic and antidepressant drugs, whereas non-steroidal anti-inflammatory drugs were removed and released under oscillating patterns. The granular biomass increased in size, but it reduced the settling velocity. Bacterial and fungal communities were acclimated to pharmaceutical inlet, whereas the archaeal population had a progressive adaptation over time. The aerobic granular sludge technology is therefore a viable approach to enhance the disposal of real hospital wastewater prior to discharge into the urban wastewater network.

Application of a portable ion chromatograph for real-time field analysis of nitrite and nitrate in soils and soil pore waters

Real-time monitoring of nitrite and nitrate is crucial for maintaining soil health and promoting plant growth. In this study, a portable ion-chromatograph (IC, Aquamonitrix) analyser, coupled with a field-applicable ultrasonic-assisted extraction method, was utilised for in-field determination of nitrate and nitrite in soils. This is the first application of this type of analyser to soil nutrients. On-site analysis of soil from a local sports field showed 94.8 ± 4.3 μg g−1 nitrate, with LODs of 32.0 μg g−1 for nitrate and 5.4 μg g−1 for nitrite. The results were in close agreement with those obtained using a conventional lab-based IC. Relative standard deviations (%RSDs) for soil analysis using Aquamonitrix were consistently below 10%. The obtained average recoveries of samples spiked with nitrite were 100% and 104% for the portable IC and conventional IC, respectively. Furthermore, to assess the suitability of portable IC for samples with high organic matter content, various natural organic fertilisers were extracted and analysed. The results showed 16.2 ± 0.7 μg g−1 nitrite and 28.5 ± 5.6 μg g−1 nitrate in sheep manure samples with LODs of 2.0 μg g−1 for nitrite and 12.0 μg g−1 for nitrate. The portable IC system was further demonstrated via real-time on-site analysis of soil pore-water acquired using a portable battery-based ceramic pore-water sampler. A continuous increase in nitrate concentration over time was observed (from 80 to 148 μg mL−1) in the soil pore-water in a vegetable garden four days after heavy rain. Unlike conventionally sampled natural waters, 7-day storage of the studied pore water samples revealed no changes in nitrate concentrations. An average of 558 ± 51 μg mL−1 nitrate was detected in the soil pore-water samples analysed on a spinach farm, immediately after irrigation.

Evaluation of movability of shale oil in organic matter in depletion production by REV-scale simulations

The oil transfer in shale oil formations includes the oil flow in inorganic and organic pores, and the diffusion in the organic matter (OM). A novel triple-continuum model (OM matrix, organic pores, inorganic matrix) is proposed coupling the oil flow (in organic and inorganic pores) and diffusion (in OM matrix). The proposed model is further validated by three-dimensional (3D) numerical simulations. The simulation results show that the proportion of oil production of the absorbed oil from OM matrix in the total shale oil production is small due to the relatively slow diffusion process. However, the diffusion of oil from OM matrix to the organic pores can provide extra energy for the oil expansion in inorganic pores, and thus can greatly increase the oil production in the depletion process. The high OM content can prolong the timespan of oil production. More absorbed oil in OM provides more elastic energy for oil depletion in organic and inorganic pores, and thus leads to higher flow rate in the late period of shale oil production. Smaller size of OM means shorter distance for oil transfer from OM to inorganic matrix, and thus accounts for higher movability of oil in OM.

Contemporary formation of ice-wedge pseudomorphs during the expansion of a thermokarst lake in Old Crow Flats, Yukon, Canada

Ice-wedge pseudomorphs (IWPs) are thermokarst structures that form by the secondary infilling of cavities left by the slow melting of ice wedges. Contemporary IWP formation in periglacial environments informs our understanding of past processes and dynamics implied by their presence in the stratigraphic record. However, contemporary IWPs are seldom studied as they are difficult to locate and observe due to the general lack of surface expression and because they can deform with time or be confused with sediment wedges. This study presents detailed information about the morphology and soil composition of IWPs that formed beneath a thermokarst lake in Old Crow Flats, northern Yukon (Canada), and provides the first conceptual model of lacustrine IWP development. Seven IWPs were unearthed along a transect perpendicular to a former eroding lakeshore in a recently (2019), partially drained lake basin. The IWPs were between 76 cm and 122 cm high and had varying morphologies, generally forming triangles pointing down or T shapes. They had a much higher organic matter content and were composed of slightly coarser sediment than their host sediment, characteristics that were shared by basin floor surface sediment found in the near-shore zone (<15 m) of the former lake. Within five meters of the former shoreline, some troughs showed pronounced subsidence due to the melting of remnant wedge ice following lake drainage. Based on ice-wedge dimensions, bank height, shore erosion rates, and field measurements of sublake active-layer thickness prior to lake drainage, it is likely that ice wedges were entirely melted by the development of the sublake active layer, prior to talik development. Together, the results indicate that the IWPs formed within 5 to 10 m of the eroding shore bank, 9 to 18 years after lake submergence, and were filled with the organic-rich lacustrine sediment that accumulated in the near-shore zone due to sediment sorting by wave action following the erosion of peaty polygonal tundra. This study highlights that IWPs can form during the natural evolution of thermokarst lakes in regions with stable permafrost and are not necessarily indicators of conditions leading to generalized permafrost degradation.

Eco-friendly natural mineral biotite as a cesium adsorbent: Utilizing low-concentration acid and hydrogen peroxide

Biotite, a phyllosilicate mineral, possesses significant potential for cesium (Cs) adsorption owing to its negative surface charge, specific surface area (SSA), and frayed edge sites (FES). Notably, FES are known to play an important role in the adsorption of Cs. The objectives of this study were to investigate the Cs adsorption capacity and behavior of artificially weathered biotite and identify mineralogical characteristics for the development of an eco-friendly geologically-based Cs adsorbent. Through various analyses, it was confirmed that the FES of biotite was mainly formed by mineral structural distortion during artificial weathering. The Cs adsorption capacity is improved by approximately 39% (from 20.53 to 28.63 mg g−1) when FES are formed in biotite through artificial weathering using a low-concentration acidic solution mixed with hydrogen peroxide (H2O2). Especially, the Cs selectivity in Cs-containing seawater, including high concentrations of cations and organic matter, was significantly enhanced from 203.2 to 1707.6 mL g−1, an increase in removal efficiency from 49.5 to 89.2%. These results indicate that FES of artificially weathered biotite play an essential role in Cs adsorption. Therefore, this simple and economical weathering method, which uses a low-concentration acidic solution mixed with H2O2, can be applied to natural minerals for use as Cs adsorbents.

Response time of soil moisture to rain in a vineyard with permanent cover

The time elapsed between the moments of maximum rainfall intensity and maximum soil moisture, known as peak to peak (P2P), is part of the hydrological response of the soil, but literature has missed this metric in any woody crop. In a vineyard with permanent vegetation cover (humid climatic conditions), the influence of two cultivars (Agudelo and Blanco Legítimo) and two zones (rows and inter-row areas) on the values of soil moisture response time, absolute change in moisture (ΔS) and P2P was evaluated for 118 rainfall events in three soil layers. 12 capacitance probes and a weather station were used, and data measured every 15 min. A positive response (ΔS > 0) was observed in 79 %, 73 % and 67 % of all events at soil depth of 5, 15 and 25 cm, decreasing ΔS with increasing soil depth. Differences of ΔS were significant among layers, but not among cultivars and zones. The maximum ΔS occurred at 15 cm, while the minimum was observed at 25 cm. No response was evident when specific thresholds were not reached: rainfall depth (0.60 mm event−1), maximum intensity (1.20 mm h−1) or duration (30 min). Topsoil conditions –high rainfall interception by the dense cover and high soil organic matter content– influenced the results at 5 cm. Rain parameters correlated well with ΔS, but weak with the response time and P2P. P2P occurred earlier in the rows than between the rows, especially at 15 cm. Shorter P2P appeared in Agudelo, with significant differences in the rows at 5 cm. P2P differed significantly among layers, increasing P2P with soil depth. Similar ΔS values appeared in Spring and Autumn, and were significantly different than those in Summer, but P2P did not differ significantly among seasons. Therefore, the magnitude and timing of the soil hydrological response were independent processes.

Lead bioaccessibility and commonly measured soil characteristics in Detroit, Michigan

Historical and contemporary use of lead (Pb) in gasoline, paints, and industry have led to its concentration in urban soils, presenting a human health risk, with disproportionate impacts on children living in urban areas. Contaminated soil is one of the major contributors to child Pb exposure. While many residents practicing urban agriculture have their soil tested to determine the amount of soil total Pb present, this measure does not provide a direct indicator of soil Pb bioaccessibility (used to predict bioavailability). Because bioavailability is ultimately necessary to determine the exposure risk, we aimed to gain a more refined understanding of Pb risk using measurements commonly performed as part of typical agricultural soil tests. Accordingly, we sampled soils from 142 residential parcels located in Detroit, MI. Soils were evaluated for: pH, organic matter content, cation exchange capacity, phosphorus, sulfur, calcium, potassium, magnesium, and sodium and total and in-vitro bioaccessible (IVBA) Pb. Detroit soil IVBA Pb ranged from 4.5% to 81%, with a mean of 39%. Total Pb, organic matter (OM) content and soil pH were found to be the most important predictors of Pb bioaccessibility. Soils typically had a relatively low OM content (mean of 5%) however, samples with higher OM content had lower IVBA (e.g., the IVBA was 15.2% smaller in soils with 7.5% OM). Soils were typically slightly basic (mean of 7.8); however, samples with pH closer to neutral had lower IVBA (e.g., the IVBA was 11.6% smaller in soils with a pH of 7.3). The proximity of soil sampling locations to former smelter locations was also found to influence Pb bioaccessibility, with samples closer to former Pb smelter sites having a somewhat higher average IVBA. Results suggest increasing soil OM content in urban soils will reduce Pb bioaccessibility. Building soil OM would therefore improve both soil fertility and decrease soil Pb bioaccessibility, imparting a predicted decrease in exposure risks.