Soil Mineral Research Articles

Transport behavior of microplastics in soil‒water environments and its dependence on soil components

Microplastic (MP) pollution has become a global concern, and the transport behavior of MPs in soil-water systems is vital in determining their distribution and potential risks to the subsurface environment. To reveal the role of various soil components on MP migration, the downward transport behavior of polystyrene (PS) MPs were explored in this study via column experiments with mono or multi-soil components as porous media. Compared with the selected soil mineral volcanic rock (VR) and fine river sand (RS), condensed soil organic matter (SOM) resulted in higher transport efficiencies for PS microparticles, with greater than 90% total mass recovery under the experimental conditions. The more surface charges of SOM than minerals contribute to the high migration efficiency of PS MPs, and electrostatic repulsion is assumed a significant driving mechanism in the migration of negatively charged PS particles in soils. The ionic strength of porewater influenced the PS migration behaviors by altering the electrostatic interactions between the MPs and soil grains. The uniform mixing of SOM with mineral grains significantly enhanced the transport efficiency of PS MPs in the columns. The results provide supports for the prediction and prevention of the risks of MPs to the subsurface environment.

Effect of dry-wet alternation on the adsorption of dissolved organic matter by soil minerals

Dry-wet alternation has an essential effect on soil minerals' adsorption of dissolved organic matter. In this study, kaolin, illite, and hematite were subjected to 0, 1, 3, and 6 dry-wet alternation incubation tests, respectively, and the changes in the characterization of the three minerals were explored by using a BET specific surface area analyzer and an X-ray diffractometer. The effects of different dry-wet alternation treatments on the adsorption of tannic acid and glucose as the representatives of dissolved organic matter were investigated by isothermal and kinetic adsorption tests as well as by different model-fitting methods. The effects of different dry-wet alternation treatments on the adsorption of tannic acid and glucose by the three minerals were investigated by isothermal and kinetic adsorption tests and different model fitting methods. The results showed that alternating dry-wet treatment could change the three minerals' specific surface area and average pore diameter to different degrees. Still, the spacing of the crystal layers did not change significantly. The dry-wet alternation did not alter the adsorption process and tannic acid and glucose adsorption mode. Still, it affected the equilibrium adsorption amount to different degrees, which was illite>hematite>kaolin, and the intensity of the effect was mainly affected by the decrease of the specific surface area of the minerals, which was not related to the change of the average pore diameter and the spacing of the crystal layers.

Evaluation of citric acid-treated natural fibres as sustainable additives for improving expansive soil performance in highway construction

This study addresses the evaluation of citric acid-treated natural fibres as sustainable additives for improving soil performance in highway construction. A series of tests were conducted on the soil to assess its baseline properties. The natural soil exhibited a Plasticity Index (PI) of 30 and Linear Shrinkage of 12%, along with a Liquid Limit (LL) of 65 and Plastic Limit (PL) of 35. Additionally, the fines content (<0.075 mm) and sand content (0.075–4.7 mm) were determined to be 79.6% and 20.4%, respectively. The soil's mineral composition included Quartz (5%), Orthoclase (3–5%), Montmorillonite (2.6%), and Illite (18.2%), with key components identified through chemical analysis: SiO2 (52.721 wt%), Fe2O3 (16.132 wt%), and Al2O3 (15.202 wt%). Subsequently, a range of tests were performed with varying additives to assess their impact on the soil's engineering properties. The sample containing 6% Sawdust (SD) additive exhibited notable improvements in multiple aspects. This sample achieved a maximum dry density (MDD) of 1856 kg/m³, surpassing the control (1900 kg/m³) and the 10% Rice Husk Ash (RHF) sample (1698 kg/m³). Furthermore, the 6% SD sample demonstrated enhanced Unconfined Compressive Strength (UCS) of 320 kPa, as opposed to the control's 121 kPa. Triaxial shear strength followed a similar pattern, peaking at 41 kPa for the 6% SD sample. The California Bearing Ratio (CBR), the 6% SD sample showcased significant improvements, achieving 41% for Unsoaked CBR and 36% for Soaked CBR. These results outperformed the control (25%) and the 4% RHF sample (37%). Additionally, the hydraulic conductivity of the 6% SD sample was notably lower at 4.98 ×10–8 cm/s compared to the control (3.35 ×10–8 cm/s) and the 4% RHF sample (4.58 ×10–8 cm/s). The Coefficient of Volume Change (Mv) further supported the superior performance of the 6% SD sample with a value of 0.6, indicating reduced settlement potential compared to the 4% RHF sample (Mv: 0.7). Based on the results, the 6% Sawdust (SD) additive consistently demonstrated the most favourable engineering properties for the expansive clay soil. hence, it is recommended that the 6% SD sample be considered as an optimal choice for enhancing subgrade material, leading to improved performance and sustainability in highway construction.

A conditional mutation in a wheat (Triticum aestivum L.) gene regulating root morphology

Key messageCharacterisation and genetic mapping of a key gene defining root morphology in bread wheat.Root morphology is central to plants for the efficient uptake up of soil water and mineral nutrients. Here we describe a conditional mutant of hexaploid wheat (Triticum aestivum L.) that when grown in soil with high Ca2+ develops a larger rhizosheath accompanied with shorter roots than the wild type. In wheat, rhizosheath size is a reliable surrogate for root hair length and this was verified in the mutant which possessed longer root hairs than the wild type when grown in high Ca2+ soil. We named the mutant Stumpy and showed it to be due to a single semi-dominant mutation. The short root phenotype at high Ca2+ was due to reduced cellular elongation which might also explain the long root hair phenotype. Analysis of root cell walls showed that the polysaccharide composition of Stumpy roots is remodelled when grown at non-permissive (high) Ca2+ concentrations. The mutation mapped to chromosome 7B and sequencing of the 7B chromosomes in both wild type and Stumpy identified a candidate gene underlying the Stumpy mutation. As part of the process to determine whether the candidate gene was causative, we identified wheat lines in a Cadenza TILLING population with large rhizosheaths but accompanied with normal root length. This finding illustrates the potential of manipulating the gene to disconnect root length from root hair length as a means of developing wheat lines with improved efficiency of nutrient and water uptake. The Stumpy mutant will be valuable for understanding the mechanisms that regulate root morphology in wheat.

Interação de plântulas de soja com rizobactérias benéficas

Beneficial rhizobacteria are multifunctional microorganisms that stimulate plant growth through direct mechanisms such as the solubilization of phosphorus and potassium present in soil minerals, biological nitrogen fixation and production of plant hormones. The objective of this study was to determine the effect of beneficial rhizobacteria on the initial development, promoting growth and resistance of soybean seedlings, aiming not only for increased production but also for agricultural sustainability through the maximization of biological efficiency in the early development of soybean seedlings. The experiment, under controlled conditions, was conducted in a completely randomized design, with four treatments and ten replications. The treatments consisted in the microbiolization of soybean seeds with: 1. Control (without microorganism); 2. Serratia marcenses (BRM 32114); 3. Bacillus spp. (BRM63573) and 4. BRM 32114 + (BRM63573). After the microbiolization of the seeds, they were sown and placed to germinate, after 12 days, the seedlings were harvested and divided into shoots and roots. The roots were washed and photographed with digital camera. The images were analyzed and determined length, diameter, surface area and volume of roots. Then, root and shoot were dried and weighed for biomass determination. Co-inculation, BRM 32114+ BRM63573, promoted greater robustness of the root system of soybean seedlings with increased length (16.2%), diameter (22.5%), volume (43.4%) and dry biomass (29.7%). The dry matter of shoots and total soybean seedlings was superior to the control treatment in all treatments with rhizobacteria. Therefore, plant growth promoting

Contrasting Phosphorus Build-up and Drawdown Dynamics in Soils Receiving Dairy Processing Sludge and Mineral Fertilisers

Sustainable utilisation of waste from the food industry is required to transition to a circular economy. The dairy industry relies on high phosphorus (P) inputs and produces large quantities of P-rich dairy processing sludge (DPS). Recycling DPS into P fertilisers provides an opportunity to decrease the reliance on chemical P fertilisers. However, current soil nutrient management planning (NMP) is based on chemical P and does not account for recycled alternatives. A pot trial using a novel isotope pool dilution technique was used to describe build-up and drawdown cycles of P in soils fertilised with DPS. Changes in available, exchangeable, and Mehlich3 P (M3-P) pools were recorded over 36 weeks of grass growth. Results demonstrated that in the period of high P demand (12 weeks), these P pools were depleted. As crop growth and demand decreased, available P recovered through mobilisation of P from exchangeable P and M3-P reserves. DPS allowed available P to recover and build up to agronomic target levels after 24 weeks. Using DPS, build-up of available and exchangeable P was slower but P use efficiency was higher at stages of slow growth. Dairy waste created a more stable P pool which could be utilised by crops over a growing season indicating that NMP needs to account for this in the decision support for growers. Isotope studies revealed that extractive agronomic tests do not capture drawdown in P reserves.

Effects of Fertilizers Applied to Cotton on Soil Mineral Nitrogen after Repeated Cropping

In this article, it is based on the fact that in the Republic of Karakalpakstan, when different rates of mineral fertilizers are applied to cotton, which is planted after winter wheat and after repeated sunflower and bean crops, the ammonium form of nitrogen is more than the nitrate form in the 0-30 cm layer of the soil. Also, it is scientifically proven that in the areas where N60P80K60 kg/ha was applied to repeated mosh, the amount of mineral nitrogen was higher than N200P140K100 kg/ha for cotton.

Soil Inorganic Carbon Formation and the Sequestration of Secondary Carbonates in Global Carbon Pools: A Review

Soil inorganic carbon (SIC), a potential carbon sink especially in arid and semi-arid environments, contributes to soil development, landscape stability, carbon (C) sequestration, and global C dynamics but due to the lack of SIC scientific reporting in most C sequestration research, its importance is unclear. A detailed overview of primary and secondary carbonate occurrence, formation, and importance is much needed to understand the role of pedogenic (PC)/secondary carbonate (a common biogeochemically derived soil mineral over time) in the SIC. The mechanisms involved in the formation of PC including carbon dioxide (CO2) from microbial respiration and precipitation, silicate mineral weathering, dissolution, and reprecipitation are highlighted. The isotopic composition of carbonates related to biological C3 or C4 carbon fixation pathways and other paleoecologic and/or climactic factors responsible for new soil carbonate formation are discussed in detail. To address the lack of knowledge associated with SIC, this review attempts to highlight the currently known aspects of the literature, and briefly describe the formation and methodologies that can aid in addressing the research gaps surrounding SIC sequestration. The authors also suggest that greater focus needs to be provided on the actual measurement of SIC to develop a more comprehensive SIC inventory to provide sound data for future research direction, and modeling efforts and to predict C terrestrial storage and change efficiently.

Zinc speciation in highly weathered tropical soils affected by large scale vegetable production

Agriculture in highly weathered tropical soils often requires considerable application of lime and fertilizers to ensure satisfactory plant nutrient levels. The consequences of these continue long-term applications is not well understood may induce changes in soil chemical properties, the abundance, and speciation of potentially toxic trace element and as well as of micronutrients in agriculture soils. In this study, we evaluated the adsorption (at pH 5) and speciation of Zn in tropical soils (both agricultural and native vegetation) as a function of fertilization and contact time using chemical fractionation analyses and X-ray absorption spectroscopy. The soils overall had high Zn adsorption capacities (∼ 700 mg kg-1), but the agricultural soil was approximately 30 % higher than of the soil under native vegetation, and the proportion of Zn in the mobile fraction was 35 % in native vegetation and 21 % in agricultural soils. Zn speciation via linear combination analysis showed a strong relationship with soil mineralogical composition and reveled that Zn associated with organic matter decreased while Zn associated with P increased after the conversion of soils from native vegetation to highly fertilized soil. Aluminosilicate soil minerals were identified as major sinks of soil Zn, accounting for 34 % of total Zn retention regardless of soil origin and land use. Association of Zn with phosphate (i.e., hopeite) was observed in the agricultural soil samples, which might be an unexpected Zn-bearing mineral in highly weathered tropical soils and could have impacts on Zn plant nutrition.

Characteristics of N Transformation of Humic Acid Urea in Different Circle Layers of the Fertisphere: A Simulated Experiment

Due to its broad yield-increasing effect and low cost, humic acid urea (HAU) has become one of the leading modified fertilizers worldwide. The fertisphere is the primary space where urea (U) granules participate in the soil nitrogen cycle, forming a nutrient concentration gradient centered on the point of fertilization. The closer the circle layers to the urea granule in the fertisphere, the higher the nitrogen concentration. However, HAU in this microregion remains poorly understood. The differences in the transformation process from the inside to outside circle layers of the U and HAU fertispheres were simulated and studied using soil incubation experiments under 20, 10, 2, 1, and 0.2 g kg−1 nitrogen inputs. The 20 and 10 g kg−1 inputs represent the layers closest to the urea granule. Within the first seven days, HAU treatment showed higher concentrations of soil ammonia-N content than U treatment within the two layers closest to the fertilizer core, while exhibiting lower concentrations under the farthest two layers. Under 2 g kg−1 nitrogen input, the nitrate nitrogen under the HAU treatment was significantly higher than that in the U treatment, indicating a higher nitrification rate. During the 42-day incubation period, soil mineral nitrogen content under the HAU treatment was higher than that for the U treatment in the two closest circles. On the 42nd day, the residual urea-N under the HAU treatment was significantly higher than that for the U treatment when the nitrogen input was higher than 1 g kg−1. The effect of higher fertilizer preservation and supply capacity of HAU in Fluvo-aquic soil was achieved by changing the urease activity and nitrification rate in fertisphere ranges closer to the fertilizer core. An improved understanding of the high-efficiency mechanism of HAU in the fertisphere process will contribute to the development of new-generation high-efficiency urea products.

Distribution of soil minerals along the toposequence of Hyang-Argopuro Volcanic Mountain, Jember, Indonesia

The study was conducted in the Hyang-Argopuro volcanic mountain in Jember, Indonesia, with the aim of assessing the distribution of soil minerals along a toposequence and their relationship to soil genesis. Three soil profiles representing the upper, middle, and lower slopes of the toposequence were analyzed. The results revealed that the predominant sand minerals in the soils are opaque minerals, weatherable minerals, amphibole groups, and ferromagnesian minerals. The presence of magnetite, primarily found in the soil profile on the upper slope, suggests the effect of the well-drained topography on its formation. Clay mineral analysis showed that halloysite dominates in soil profile 1, along with traces of gibbsite and cristobalite in the surface horizon. Soil profile 2 is characterized by a combination of halloysite and illite, while kaolinite and illite dominate in soil profile 3. The presence of illite in these soils aligns with previous studies conducted in volcanic regions. The degree of soil development follows the sequence: Soil Profile 2 &gt; Soil Profile 1 &gt; Soil Profile 3. This corresponds to the soil classification, where soil profile 3 is classified as an Alfisol, soil profile 1 as a Mollisol, and soil profile 3 as an Inceptisol. The Andic properties, such as low bulk density and high pH in NaF, observed in soil profile 1 suggest its development from an Andisol. Overall, the study findings highlight the significant influence of basaltic andesite parent material, mountainous topography, and warm and wet climate on the mineral composition and development in the area.

Novel application of sustainable coal-derived char in cement soil stabilization

Cement soil stabilization is a commonly used method to improve in-situ soil properties catering to different geotechnical applications. However, cement manufacturing is typically associated with high CO2 emissions and energy consumption. Coal char is a sustainable and environmentally friendly material derived from the coal pyrolysis process. Traditionally used for combustion and gasification, recent research has revealed its potential to improve the engineering performance of cement-based construction and building materials. This study explores the innovative use of coal char in cement soil stabilization. Examining various cement contents (5%, 10%, and 20%) and char contents (10%, 20%, and 30%), the properties of char-cement stabilized soils, including mineralogy, density, water content, thermal conductivity, unconfined compressive strength (UCS), and mechanical properties under triaxial compression, are comprehensively investigated and compared with cement stabilized soil. It is found that char promotes both cement hydration and reaction between soil minerals and cement. The thermal conductivity and UCS of char-cement stabilized soil are 0–9% lower and 8–16% higher, respectively than that of cement stabilized soil. Under triaxial compression, the addition of char in stabilized soil leads to 23.7% increase in shear strength, 17.7% increase in cohesion, and 16.7% increase in the angle of internal friction. In conclusion, the introduction of coal char into traditional cement soil stabilization demonstrates a novel approach to achieving sustainability and enhancing engineering performance in relevant geotechnical applications.

Nitrous oxide emissions are driven by environmental conditions rather than nitrogen application methods in a perennial hayfield.

Agricultural best management practices (BMPs) intended to solve one environmental challenge may have unintended climate impacts. For example, manure injection is often promoted for its potential to reduce runoff and nitrogen (N) loss as NH3 , but the practice has been shown to increase N2 O, a powerful greenhouse gas, compared to surface application. Urease inhibitor application with N fertilizer is another BMP that can enhance N retention by reducing NH3 emissions, but its impact on N2 O emissions is mixed. Thus, we measured N2 O, CO2 , soil mineral N availability, soil moisture, soil temperature, and yield in a 2-year perennial hayfield trial with four fertilization treatments (manure injection, manure broadcast, synthetic urea, and control) applied with or without a urease inhibitor in Alburgh, VT. We used linear models to examine treatment effects on daily and cumulative N2 O emissions and a boosted regression tree (BRT) model to identify the most important drivers of daily N2 O fluxes in our trial. While fertilization type had a significant impact on N2 O fluxes (p<0.05), our treatments explained an unexpectedly small amount of the variation in emissions (R2 =0.042), and urease inhibitor had no effect. Instead, soil moisture was the most important predictor of daily N2 O fluxes (39.7% relative influence in BRT model), followed by CO2 fluxes, soil inorganic N, and soil temperature. Soil moisture and temperature interacted to produce the largest daily N2 O fluxes when both were relatively high, suggesting that injecting manure during dry periods or during wet but cool periods could reduce its climate impacts.

Soil texture, fertilization, cover crop species and management affect nitrous oxide emissions from no-till cropland

Cover crops reduce nitrate leached, but effects on nitrous oxide (N2O) emissions are mixed. Cover crops can reduce N2O emissions by reducing levels of mineral nitrogen (N) and surface soil moisture during spring. Cover crops can also increase N2O emissions by adding organic substrates, releasing N during decomposition, or increasing summer soil water content. Winter-killed cover crops can increase soluble organic C and N during periods of typically low microbial activity. We hypothesized that planting a cover crop mix of radish (Raphanus sativus)-crimson clover (Trifolium incarnatum)-rye (Secale cereale) would increase direct N2O emissions relative to no cover crop, and result in lower direct and indirect N2O emissions than planting radish alone. We also hypothesized that extending the cover crop growing season, by planting earlier and killing later, would increase direct N2O emissions during winter, decrease direct N2O emissions during summer, and decrease indirect N2O emissions. To address these hypotheses, we conducted two field experiments (on sandy and silty soils) over four site-years. We measured cover crop biomass and N content, soil mineral N concentrations, soil moisture, green canopy cover, soil porewater nitrate, direct N2O emissions, and estimated indirect N2O emissions. Nitrous oxide emissions were ~ 7.8 times greater at the silty than the sandy sites due to greater soil moisture retention. Site-years with high radish biomass exhibited greater direct N2O emissions than sites with low radish biomass following winter-kill. Indirect N2O emissions were decreased ~7 % by planting cover crops and by ~70 % by planting cover crops early. Fertilizer induced emission peaks were 8.2 times greater than all previous N2O emissions combined at a silty site. Our results suggested that soil texture and fertilization played an important role in direct N2O emissions, while cover crop species, biomass, and timing played a more important role in NO3 leached, and thus, indirect N2O emissions.

Effects of the Cultivation Methods on the Sensory Quality and Phytochemical Profiles of Satsuma Mandarin (Citrus unshiu)

Citrus fruits have a distinctive flavor and can convey health benefits because of their unique phytochemicals. Phytochemical profiles are influenced by many factors, including variety and environmental growing conditions; however, the effect of the cultivation methods on the phytochemical profile of Satsuma mandarin (Citrus unshiu) has received little attention. In this study, we examined the relationships between the cultivation conditions, sensory quality, and phytochemical profiles of C. unshiu cultivated using four methods: open field, greenhouse, film mulching, and tunnel farming. The soil water content differed significantly between the cultivation methods and showed a strong positive correlation with sourness, bitterness, and astringency and a strong negative correlation with sweetness. The metabolites of C. unshiu were not associated with the soil water content but with the soil mineral content, including nitrogen (N+), phosphorus (P+), and potassium (K+). The soil P+ and K+ content was positively correlated with most secondary metabolites. The relative abundance of sugars did not differ significantly between the cultivation methods; however, the sweetness was higher under film mulching than under the other cultivation methods because of the suppression of sweetness by bitter compounds. We did not investigate the effect of other growing conditions, such as sunlight; however, the results improve our understanding of the effect of cultivation methods on the quality of C. unshiu and may inform crucial decisions concerning citrus cultivation.

Assessing Suitability of Different Extractants for Estimating Plant Available Boron in Lateritic Soils (Alfisols)

ABSTRACT The depth-wise distribution of plant available boron (B) extracted by dilute HCl (HCl), tartaric acid (TA), hot calcium chloride (HCC), hot water (HW), ammonium acetate (AA), Ammonium Bicarbonate-Diethylene Triamine Penta Acetic acid (AB-DTPA) and mannitol calcium chloride (MCC) in some acidic lateritic soils (Alfisols) of Birbhum, West Bengal, India, was examined in relation to their physicochemical properties and grain yield, concentration and removal of B by rice grain to screen out the most suitable extractant for lateritic soils. The highest overall mean B concentration of surface soils (0.325 mg kg−1) was obtained by 0.05 M HCl, whereas its lowest content was obtained by MCC (0.145 mg kg−1) and with increasing depth its content was decreased for all the extractants used. The sequence of B extraction by various extractants was as follows: HCl > TA > HCC > HW > AA > AB-DTPA > MCC. Higher extractability of HCl is due to lower pH and attendant dissolution of soil minerals. Most often, decrease in organic carbon, clay, CEC, amorphous iron and aluminum oxides or increase in manganese oxide contributed to the observed drop in B along soil depth. The B extracted by different extractants showed significant positive correlations among themselves. The HCl extracted B showed the highest correlation with grain yield, concentration, and removal of B by rice grain. The HCl extractable B enhanced adjusted R2 value in multiple regression equation, boosting the predictability of the model. Thus, in acidic lateritic soils (Alfisols), the 0.05 M HCl is the best extract for estimating plant available B.

No-tillage with total green manure mulching: A strategy to lower N2O emissions

ContextGreen manure application in agricultural soil is known to enhance nitrogen use efficiency and crop yield. However, limited research exists on the potential effects of green manure returning on N2O emissions. ObjectiveThis study aims to investigate the effects and underlying mechanisms of N2O emissions in maize fields under different green manure management practices. MethodsA field experiment was conducted using common vetch as a green manure crop following the harvest of spring wheat. The study employed a completely randomized block design and examined four treatments: tillage with total green manure incorporation, no-tillage with total green manure mulching (NTG), tillage with green manure root incorporation (T), and no-tillage with aboveground green manure removal (NT). The study explored both non-biological and biological factors affecting nitrogen conversion to elucidate the mechanisms in N2O emissions. ResultsN2O emissions were 17.7% lower in TG and NTG compared to T and NT (P < 0.01), with NTG showing a 12.2% reduction compared to TG (P < 0.05). NTG also exhibited the lowest average N2O fluxes at 24.2 μg N m−2 h−1. In terms of non-biological factors, N2O emissions were negatively correlated only with aggregate NH4+-N and NO3－-N (P < 0.05). Despite increasing soil mineral nitrogen, NTG had approximately 72.3%− 92.4% of it in the form of aggregate nitrogen. In addition, under NTG, the aggregates have better structure and stability. q-PCR analysis revealed higher nos Z gene abundance in NTG than in other treatments (P < 0.05). Regression analysis showed that N2O emissions were negatively correlated with nos Z's abundance and N2O reductase diversity (P < 0.05). ConclusionsNo-tillage with total green manure mulching (NTG) effectively reduced N2O emissions by enhancing mineral nitrogen in soil aggregates and increasing the abundance of the nos Z gene. ImplicationsOur findings offer valuable insights for long-term agricultural management strategies aimed at improving nitrogen retention and mitigating climate change impacts.

Molecular Structure and Conformation of Biodegradable Water-Soluble Polymers Control Adsorption and Transport in Model Soil Mineral Systems.

Water-soluble polymers (WSPs) are used in diverse applications, including agricultural formulations, that can result in the release of WSPs to soils. WSP biodegradability in soils is desirable to prevent long-term accumulation and potential associated adverse effects. In this work, we assessed adsorption of five candidate biodegradable WSPs with varying chemistry, charge, and polarity characteristics (i.e., dextran, diethylaminoethyl dextran, carboxymethyl dextran, polyethylene glycol monomethyl ether, and poly-l-lysine) and of one nonbiodegradable WSP (poly(acrylic acid)) to sand and iron oxide-coated sand particles that represent important soil minerals. Combined adsorption studies using solution-depletion measurements, direct surface adsorption techniques, and column transport experiments over varying solution pH and ionic strengths revealed electrostatics dominating interactions of charged WSPs with the sorbents as well as WSP conformations and packing densities in the adsorbed states. Hydrogen bonding controls adsorption of noncharged WSPs. Under transport in columns, WSP adsorption exhibited fast and slow kinetic adsorption regimes with time scales of minutes to hours. Slow adsorption kinetics in soil may lead to enhanced transport but also shorter lifetimes of biodegradable WSPs, assuming more rapid biodegradation when dissolved than adsorbed. This work establishes a basis for understanding the coupled adsorption and biodegradation dynamics of biodegradable WSPs in agricultural soils.

Interfacial Adsorption and Dynamics of Fluorotelomers with Soil Minerals –Mechanistic Insights

Following the global regulation of legacy PFAS molecules, fluorotelomer molecules have been widely employed as replacements to PFOS in aqueous film-forming foam (AFFF) and PFOA in other products. Recent field...

Pollution sources and metallic elements mobility recorded by heavy minerals in soils affected by Cu-smelting (Legnica, SW Poland)

Abstract Heavy mineral particles are widely used in Earth science studies to show sediment provenance and weathering conditions. Such particles are particularly useful in polluted soils surrounding mining and smelting facilities because heavy minerals are common by-products of these activities and may accumulate in the soils. As such, the particles are suitable indicators of metallic element carriers and their stability in the soil environment. In this study, we analyze heavy mineral particles in two soils surrounding the active copper smelter (Legnica, SW, Poland). We show that particles associated with different smelting activities dominate the heavy mineral fraction. We note the general absence of sulfides in the fraction indicating that these minerals might have been entirely dissolved, but timing of this dissolution is uncertain (before or after deposition within soils). Currently, the carriers of potentially toxic elements are mainly secondary Fe oxides. Studies aiming at better estimation of the proportion of metallic elements contained in heavy mineral particles are needed to fully use the potential of these phases in polluted soil studies. We estimate that Pb contained in Pb-rich silicate glass constitutes &lt;0.5% of the total Pb budget and Pb contained in secondary Fe oxides is over 1% of the total budget, but these are minimal estimates.