Exchangeable Cations Research Articles

Evaluation of the Effects of Returning Apple Shoots In Situ on Soil Quality in an Apple Orchard

Fruit tree shoots are potential useful resources that are rich in carbohydrates and inorganic nutrients but that are not typically utilized in sustainable agriculture. Our objective was to evaluate the soil properties and soil quality of an orchard after returning apple shoots in situ and to investigate the contribution rate of apple shoots as an exogenous source of organic carbon for fertility amendment of the apple root domain. One-year-old apple shoots were pruned in spring before budding, chopped into 10 cm sections and placed on the soil surface. Soil samples were collected in the first year and third year after returning the shoots. Principal component analysis, Pearson correlation analysis and soil quality index (SQI) comprehensive analysis methods, combined with fuzzy mathematics, were adopted to evaluate the effects of returning apple shoots on comprehensive soil quality, including the soil fertility indicators, soil exchangeable cations, soil neutral sugar and amino acids. Increases in soil organic carbon (SOC), available potassium (K), and available phosphorus (P) were observed in different layers of the orchard soil with returned shoots over time. The total nitrogen (N) content decreased by 18.75% and 13.79% in the 0–20 cm and 20–40 cm soil layers, respectively, in the first year, but increased significantly in the third year. Significant increases in exchangeable cations (Na+, Ca2+, Mg2+) in the 0–20 cm soil layer were also observed in the third year after returning shoots, compared to the control. In addition, obvious accumulation of glucose and xylose was observed in the 0–20 cm soil layer compared to the controls in the third year after returning shoots. The total water-soluble free amino acid contents in the third year after returning shoots were 1.08- and 1.16-times higher, respectively, than those of the controls in the 0–20 cm and 20–40 cm soil layers. The SQI in the third year was higher than that of the other treatments in the 0–20 cm soil layer. This study suggests that abandoned apple shoots used as a supplementary carbon source for orchards enhanced the soil fertility of different soil layers, regulated the soil micro environment, and improved the overall soil quality.

Karakteristik Fisik, Kimia dan Mineral Tanah Di Lokasi Kampus IAIN- Ambon Kecamatan Sirimau Kota Ambon

The aims of this study was to identify morphological characteristics, clay mineral composition and soil similarity index between two soil profiles at the IAIN campus. The results showed that soil color characteristics of soil layers of both soils are different. Both soil profiles have deep solums with loam to sandy loam texture distribution. The increasing of clay content in the B horizon of both soil profiles is still weak as indicated by the present of a Bw (kambik) horizon. Soil structure is a subangular blocky with fine to coarse sizes and weak to strong structural development. Soil consistency is slightly sticky to sticky. Cation exchange capacity is very low as indicated by low Ca dan Na, medium to high Mg and high Na soil exchangeable cations. The dominant clay mineral in both soil profiles is kaolonit, which is formed by unwell-consolidated weathering materials mixed with weathering-resistant quartz. The silt/clay ratio and CEC values shows similarity between layers between both profiles, however, the Ca/Mg ratio shows dissimilarity. The soil type in both soil profiles is district Kambisol (Typic distrudepts) categorized as a developed soil

Karakteristik Fisik, Kimia dan Mineral Tanah Di Lokasi Kampus IAIN- Ambon Kecamatan Sirimau Kota Ambon

The aims of this study was to identify morphological characteristics, clay mineral composition and soil similarity index between two soil profiles at the IAIN campus. The results showed that soil color characteristics of soil layers of both soils are different. Both soil profiles have deep solums with loam to sandy loam texture distribution. The increasing of clay content in the B horizon of both soil profiles is still weak as indicated by the present of a Bw (kambik) horizon. Soil structure is a subangular blocky with fine to coarse sizes and weak to strong structural development. Soil consistency is slightly sticky to sticky. Cation exchange capacity is very low as indicated by low Ca dan Na, medium to high Mg and high Na soil exchangeable cations. The dominant clay mineral in both soil profiles is kaolonit, which is formed by unwell-consolidated weathering materials mixed with weathering-resistant quartz. The silt/clay ratio and CEC values shows similarity between layers between both profiles, however, the Ca/Mg ratio shows dissimilarity. The soil type in both soil profiles is district Kambisol (Typic distrudepts) categorized as a developed soil

Atlantic rainforest natural regeneration in fragmented formations affected by increasing human disturbance

Forests provides major ecosystem services worldwide. The Brazilian Atlantic Forest (BAF) has been dramatically devastated, with fragmentation processes jeopardizing its long-term sustainability. This study investigated the structure and successional dynamics in BAF natural regeneration along an anthroposequence characterized by increasing human disturbance histories as: secondary (SF) > disturbed (DF) > late forest (LF). We aimed to understand how and the degree to which BAF fragmentation and human disturbance affected plants, soils, and the whole soil-plant relationships and feedbacks. We investigated the natural regeneration conditions of plants (using plant classification and quali-quantitative analyses) and soil chemistry (including pH-CaCl2, H + Al, C, N, Pt, cation-exchange capacity (CEC), exchangeable cations, Al, B, Cu, Fe, K, Mn, and Zn) at twelve permanent, 2000 m2 plots, distributed across LF, DF, and SF forests. Significant differences were determined by ANOVA. Correlation matrix (CM) and factor analysis (FA) were used for understanding correlations and feedbacks/variability among investigated parameters, respectively. Most of investigated plant and soil parameters showed significant differences (p < 0.05) between more developed plant formations (LF) vs less developed ones (SF), with differences mainly due to soil's development stage. All investigated forest formations are featured by a great influence of the soil-plant relationships and feedbacks, with a decreasing magnitude as LF → DF → SF. Thus, there is a direct, statistically recognizable impact of both “recent” as well as “ancient” human disturbance on investigated soil-plant formations. The anthropogenic influence clearly affected not only plant and soil as “separate” systems but the whole complex of interactions and feedbacks among ecosystem components. A decreasing quality in soil and plant parameters was observed as human disturbance increased. We demonstrated that BAF plant and soil require decades for their recovery after human disturbances, with complex mechanisms and behaviors in the relationships among ecosystem components. The results can be useful for managing future recovery in an ecosystem of worldwide strategic importance.

Agronomic Evaluation of Recycled Polyurethane Foam-Based Growing Media for Green Roofs

Green roofs are very popular and their individual surface area is constantly growing. Considering that the organo-mineral materials used in planting growing media (GM) are often non-renewable resources, the search for alternative materials from waste recycling is a challenge. Among these, recycled polyurethane (PU) foams are light and porous. The objective of this study was to evaluate the potential agronomic valorisation of PU foams for extensive green roofs. Three GM based on compost, PU foam and topsoil were developed and tested in situ for 18 months along with four plant species in containers containing 15 cm of GM. The agronomic properties of the GM and their contaminant contents were evaluated, as well as the plant aerial and root biomasses and trace element levels. The main results of this work are that GM are suitable for plant growth. Compost ratio effect resulted in a lower pH and higher exchangeable cations in GM1, whereas topsoil proportion effect mainly decreased macroporosity and increased nutrient contents. Furthermore, due to the high trace element load in the compost, hyperaccumulator plants such as Hypericum calycinum and Stipa tenuissima should be preferred. Ecotoxicological analyses will be carried out to validate the absence of risk of PU foam contaminants being released in the environment before proposing these types of GM to green roof developers.

Impact of liming on extractable phosphorus, exchangeable base cations, and effective cation exchange capacity of eastern Free State soils

Soil acidity can adversely affect wheat production in the eastern Free State, South Africa. Liming of the soils is therefore essential. The aim of this study was to establish whether extractable phosphorus (P), exchangeable calcium (Ca), magnesium (Mg) and potassium (K) concentrations and cation ratios remained within recommended ranges after liming. Incubation and field studies were done on soils of wheat fields at Kestell, Fouriesburg, Prinsloo and Melrose in the eastern Free State, South Africa. Lime was applied at different rates to induce soil acidity ranges for determination of Bray 1 extractable P and ammonium acetate (NH4OAc) exchangeable Ca, Mg and K concentrations. Cation ratios (Ca:Mg, Mg:K and (Ca + Mg):K) and effective cation exchange capacity (ECEC) were also calculated. Apart from the Prinsloo soil, liming decreased extractable P concentration only in the incubation study. In the incubation and field studies exchangeable Ca and Mg concentrations increased while exchangeable K concentration remained unchanged. Despite liming of the soils, exchangeable Ca and Mg concentrations at Kestell and Fouriesburg were still less than the required thresholds. The Ca:Mg ratio decreased at both sites while the Mg:K and (Ca + Mg):K ratios increased with liming. Liming increased ECEC of all soils at all four sites. Our results show that liming does not always result in the recommended cation levels required for soil fertility.

Evolution Mechanism of Arsenic Enrichment in Groundwater and Associated Health Risks in Southern Punjab, Pakistan.

Arsenic (As) contamination in groundwater is a worldwide concern for drinking water safety. Environmental changes and anthropogenic activities are making groundwater vulnerable in Pakistan, especially in Southern Punjab. This study explores the distribution, hydrogeochemical behavior, and pathways of As enrichment in groundwater and discusses the corresponding evolution mechanism, mobilization capability, and health risks. In total, 510 groundwater samples were collected from three tehsils in the Punjab province of Pakistan to analyze As and other physiochemical parameters. Arsenic concentration averaged 14.0 μg/L in Vehari, 11.0 μg/L in Burewala, and 13.0 μg/L in Mailsi. Piper-plots indicated the dominance of Na+, SO42−, Ca2+, and Mg2+ ions in the groundwater and the geochemical modeling showed negative saturation indices with calcium carbonate and salt minerals, including aragonite (CaCO3), calcite (CaCO3), dolomite (CaMg(CO3)2), and halite (NaCl). The dissolution process hinted at their potential roles in As mobilization in groundwater. These results were further validated with an inverse model of the dissolution of calcium-bearing mineral, and the exchange of cations between Ca2+ and Na+ in the studied area. Risk assessment suggested potential carcinogenic risks (CR > 10−4) for both children and adults, whereas children had a significant non-carcinogenic risk hazard quotient (HQ > 1). Accordingly, children had higher overall health risks than adults. Groundwater in Vehari and Mailsi was at higher risk than in Burewala. Our findings provide important and baseline information for groundwater As assessment at a provincial level, which is essential for initiating As health risk reduction. The current study also recommends efficient management strategies for As-contaminated groundwater.

Preparation of a nanocomposite hydrogel with high adhesion, toughness, and inherent antibacterial properties by a one-pot method

In the biomedical field, it is challenging to develop a multifunctional hydrogel with superior tissue adhesion, cell compatibility, inherent antibacterial properties, and excellent mechanical properties. Herein, we designed a material system with a synergistic effect and prepared a multifunctional nanocomposite hydrogel using a one-pot method, with N-maleyl dopamine (MDA), montmorillonite (MMT), chitosan-N-2-hydroxypropyl trimethylammonium chloride (HACC), and acrylamide as materials. As a nanofiller, montmorillonite enhanced the mechanical properties of the hydrogel, achieving superior tensile strength (47 KPa), considerable tensile strain (660%), and desired compressive property. The cations exchange between HACC and MMT promoted the uniform dispersion of MMT to synthesize hydrogels with a consistent structure. Antibacterial test results of hydrogels showed an excellent inhibitory effect against Escherichia coli (> 96%) and Staphylococcus aureus (> 98%). Moreover, these nanocomposite hydrogels exhibited excellent biocompatibility (> 88%) and superior adhesion (> 14 KPa), making them ideal as wound dressing materials. The full-thickness skin defect experiments in mice showed that nanocomposite hydrogel dressings significantly accelerated wound closure and promoted tissue regeneration and collagen deposition.

Improving Selected Chemical Properties of a Paddy Soil in Sabah Amended with Calcium Silicate: A Laboratory Incubation Study

In Malaysia, the main constraints of rice yield and productivity are infertile soils and poor management practices because these soils are characterized by low pH, low nutrient availability, low organic matter, and high exchangeable Al and Fe ions, due to high rainfall and hot temperatures. Thus, an incubation study was conducted to determine the optimum amount of calcium silicate (HmbG brand) to improve the soil pH, electrical conductivity (EC), exchangeable Al, available P, and cation exchange capacity (CEC) of a paddy soil in Sabah, Malaysia. The Kelawat series (Typic Dystrudept) soil was incubated with calcium silicate at the application rates of 0 (T1), 1 (T2), 2 (T3), and 3 t ha−1 (T4) using a Completely Randomized Design (CRD) in triplicates for 30, 60, 90, and 120 days. The calcium silicate used significantly improved soil pH because of the release of SiO44− and Ca2+ ions, which neutralized and immobilized H+ ions. Furthermore, the neutralizing effects of the amendment impeded Al hydrolysis by up to 57.4% and this resulted in an increase in the available P in the soil by 31.26% to 50.64%. The increased availability of P in the soil was also due to the high affinity of SiO44− to desorb P from soil minerals and it is believed that SiO44− can temporarily adsorb exchangeable base cations such as K+, Ca2+, Mg2+, and Na+. Moreover, applying calcium silicate at 3 t ha−1 improved soil CEC by up to 54.84% compared to that of untreated soils (T1) because of increased pH and the number of negatively charged sites. The most suitable application rate of the calcium silicate was found to be 3 t ha−1 (T4). These findings suggest that calcium silicate can improve soil productivity and agronomic efficiency in rice farming. Greenhouse and field trials are necessary to ascertain the effects of the recommended treatments of this incubation study on soil productivity, rice growth, and yield.

Remediation Effect and Mechanism of Inorganic Passivators on Cadmium Contaminated Acidic Paddy Soil

Cadmium (Cd) is one of the main pollutants in acidic paddy fields, and its accumulation in rice (Oryza sativa L.) and subsequent transfer to the food chain is an important environmental issue in China. In our field study, three types of inorganic passivators (silicon-calcium-magnesium-potassium fertilizer (SCMK), calcium magnesium phosphate fertilizer (CMP), and lime (L) at the rate of 750, 1500, and 2250 kg·hm-2, respectively) were applied to acidic paddy soils polluted by the heavy metal Cd in southern Zhejiang province. The objective of this study was to reveal the effects and chemical mechanisms of passivators on soil acidification and Cd accumulation in rice. The field experimental results showed that the three passivators could effectively improve soil acidification and reduce Cd accumulation in rice grains. The application of 2250 kg·hm-2 SCMK, CMP, and L increased soil pH by 0.62, 0.65, and 0.86 units; decreased exchangeable acidity by 67%, 69%, and 78%; and reduced the content of Cd in brown rice by 73%, 68%, and 77%, respectively. The application of 2250 kg·hm-2 SCMK, CMP, and L reduced the content of Cd in brown rice planted on polluted paddy rice fields to lower than 0.2 mg·kg-1, which reached the national food safety standard. Compared with the control, the application of SCMK, CMP, and L significantly (P<0.05) decreased the content of available Cd extracted by DTPA; decreased the contents of weak acid-extractable (F1) and reducible (F2) Cd; and increased the content of residual (F4) Cd. Correlation analyses indicated that Cd content in brown rice was significantly negatively correlated with soil pH and exchangeable cation content and significantly positively correlated with DTPA-Cd, weak acid-extractable (F1) and reducible (F2) Cd, and exchangeable Al contents. The partial least squares path model (PLS-PM) was used to analyze the relationship between the Cd content of brown rice, DTPA-Cd, and various chemical forms of Cd and soil properties. The direct path coefficients of soil exchangeable cations on Cd content in brown rice, available cadmium, and rice yield were -0.566, -0.866, and 0.873, respectively. Soil pH indirectly affected Cd content of brown rice mainly by directly affecting available Cd in soil. Field experiments demonstrated that the three passivators SCMK, CMP, and L were effective technologies for the safe production of rice in acidic paddy soils polluted by Cd. The possible mechanism for passivators reducing the bioavailability of Cd in soil and its accumulation in brown rice contributed to increased exchangeable cations in the soils. These findings could provide a scientific basis for the safe production of rice in acidic paddy soil polluted by heavy metals.

Cation Short-Range Ordering of MgAl2O4 and NiAl2O4 Spinel Oxides at High Temperatures via In Situ Neutron Total Scattering.

Complex oxides that adopt the isometric spinel structure (AB2O4) are important for numerous technological applications and are relevant for certain geological processes, which involve exposure to extreme environments such as high pressures and temperatures. Recent studies have shown that the changes to the spinel structure caused by these environments are complex and depend on the material length scale under consideration. In this study, we have expanded this approach to the behavior of spinels under high temperatures. In situ neutron total scattering experiments, coupled with pair distribution function analysis, performed on two spinel compositions with various levels of pre-existing disorder (MgAl2O4 and NiAl2O4) revealed that both compositions trend to a state of maximum disorder where the A and B cations are randomly distributed among the two available sites. Temperature-induced cation inversion, conventionally understood as an exchange of cations on the A and B sites, is locally expressed as an atomic rearrangement to a tetragonal symmetry, a correlation that is retained up to the maximum temperature studied (1000 °C). A complex thermal expansion behavior is revealed wherein the oxide materials expand heterogeneously at the level of coordination polyhedra with an apparent dependence on bond strength.

Assessment of soil fertility using the soil fertility index method on several land uses in Tutur District, Pasuruan Regency of East Java

&lt;p&gt;Changes in land use have an impact on the level of soil fertility. Soil management, such as land cover systems and the environment, are supporting factors. Assessment of soil fertility index using indicators of soil chemical properties such as organic C, availability of nutrients nitrogen (N), phosphorus (P), cation exchange capacity (CEC), and exchangeable cations (K, Ca, Mg, Na). The research was conducted in Tutur District, Pasuruan Regency, with a survey of 5 land uses, i.e., mixed crops, coffee plantations, apple plantations, vegetable fields, secondary forests, and conservation forests. Observations were made on elevation, slope, and vegetation. Parameters of physical properties measured were soil texture and aggregate stability. Observations of chemical properties included organic C, N, P, CEC, exchangeable cation (K, Ca, Mg, Na), and soil pH. Soil Fertility Index (SFI) data were analyzed using the Least Significant Difference method at a 5% level. The results showed the diversity of soil fertility levels obtained from the calculation of the soil fertility index. The soil fertility index value in 5 land uses in Tutur District ranged from 0.67 to 1.00. Coffee plantations had the highest SFI score of 1.00; this condition was supported by an organic C indicator of 6.21% and a CEC value of 39.12 cmol kg&lt;sup&gt;-1&lt;/sup&gt;. Conservation forest is the land use with the lowest SFI value of 0.67. The value of CEC and cation exchange in conservation forests are factors that impact the low value of SFI. &lt;/p&gt;

Vegetative Growth Responses of Castor (Ricinus communis) and Senna (Senna occidentalis) to Low Dose Zinc (Zn) Spiking of Agricultural Soil in Kano, Northern Nigeria

The aim of the research is to assess the viability of castor (Ricinus communis) and senna (Senna occidentalis) plants up to 90 days after planting (DAP) in agricultural soil spiked with different concentration of zinc in the screen house. Agricultural soil was collected from Bayero University Kano, at 11° 98ʹ 32.59″N; 8°42ʹ 43.97″E. Soil texture, pH, electrical conductivity (EC), organic carbon (OC), nitrogen (N), phosphorus (P) and exchangeable cations (K + , Ca + , Mg + and Na + ) were determined. Castor and senna were planted in soil spiked with 2 mg/kg, 4mg/kg and 8 mg/kg of zinc sulphate (ZnSO4) each. Control plants containing only agricultural soil without spiking with zinc were added and the set up replicated 4 times. Plant height, number of leaves and root length were assessed at 45 and 90 days after planting (DAP). The soil was sandy loam, slightly acidic, C, N, P and K+ had mean values of 0.41%, 0.33 mg/kg, 14.33 mg/kg and 0.39 cmol/kg respectively. There were significantly higher (p&lt;0.05) mean values for height (16.85cm) and root length (17.35 cm) of control castor plants than those treated with zinc at 45 DAP. At the termination of the experiment (90 DAP), senna plants in control had significantly higher mean values for height (29.5 cm) than all other treatments. All concentrations of zinc used in this work did not seem to have much negative effects on the vegetative growth of both test plants.

Simulation of Adsorption Process of l-Tryptophan on Mixed-Mode Resin HD-1 with Combined Physical Adsorption and Ion Exchange.

The mass-transfer process of l-tryptophan (l-Trp) in the hydrophobic interaction/ion-exchange mixed-mode resin HD-1 particles and fixed bed was studied experimentally and theoretically. The adsorption kinetics of l-Trp in single-component and multicomponent adsorption systems was investigated under different pH conditions. The co-adsorption of sodium ions (Na+) and l-Trp anions was found to be negligible. A modified liquid-film linear driving force model considering the physical adsorption of l-Trp zwitterions and anions as well as ion exchange of l-Trp cations was proposed. The dissociation equilibria of l-Trp molecules and functional groups on the resin were introduced in the model. The model could well fit the kinetic adsorption curves of l-Trp at different pH values. The presence of Na+ and the impurity amino acid l-glutamic acid (l-Glu) did not significantly affect the mass-transfer rate of l-Trp. The dynamic adsorption processes of l-Trp under different pH and concentration conditions were studied. A modified transport-dispersive model considering axial diffusion, liquid-film mass transfer, and a combined physical adsorption and ion-exchange equilibrium was established, which could predict the adsorption breakthrough curves of l-Trp well. During the dynamic adsorption process, the pH of mobile phase in the fixed bed changed with changing the l-Trp concentration in the mobile phase. l-Trp was well separated from Na+ and l-Glu with the purity of l-Trp higher than 99%, the recovery rate higher than 95%, and a concentration of 4.69 × 10–3 mol/L. The elution chromatographic peaks of l-Trp, l-Glu, and Na+ and the pH of the outlet solution were predicted satisfactorily.

ADSORPTION STUDY OF ACETONE ON THE SORBENTS BASED ON MONTMORILLONITE

Corresponding cation forms of the montmorillonite samples taken from the Ag-Dere bentonite deposit were obtained by processing them with Co2+ and Ni2+ salts. The nature and amount of acid sites formed on the surfaces of the obtained samples were studied by adsorption of acetone using the derivatographic method. The critical diameter of the acetone molecule is d = 5.6A0 and pkα = -7.2. Analysis of derivatograms shows that the mass loss changes depending on the ionic radius, nature and temperature of the cation exchanges as follows: Co2+ mont&gt; Ni2+ mont&gt; natural mont. Based on the conducted study it was estableshed that there are weak, medium and strong electron-acceptor centers on the surface of the sorbent which differ energetically. The endothermic effect observed on the DTA curve at a temperature range of 219.3–566.30C characterizes the physical adsorption of an acetone molecule on the surface of a montmorillonite sample. The effects observed at 706.9 and 775.70C characterize the strong acid sites. The amount of electron-acceptor centers formed on the surface of monmorillonite changes depending on the charge of cation exchangers. The number of electron-acceptor centers formed on the surface of Co2+ bentonite is higher than in other samples. The amount (a.mmol.g) and desorption energy (E, kDc, mol-1) of acetone molecule desorbed from the active sites in different temperature ranges were calculated. It was determined that the most capable of adsorbing acetone molecules is Co2+-montimorillonite, which can be used as a sorbent to prevent envoiremental pollution with acetone. Corresponding cation forms of the montmorillonite samples taken from the Ag-Dere bentonite deposit were prepared by processing with Co2+ and Ni2+ salts. The nature and amount of acid sites formed on the surfaces of the obtained samples were studied by adsorption of acetone using the derivatographic method. Based on the conducted study it was estableshed that there are weak, medium, strong electron-acceptor centers on the surface of the sorbent which differ energetically. The amount (a.mmol.\g) and desorption energy (E, kDc, mol-1) of acetone molecule desorbed from the active sites in different temperature ranges were calculated. As a result of the research, it was found that the most capable of adsorbing acetone molecules is Co2+-form of montimorillonite, which can be used as a sorbent to prevent envoiremental pollution with acetone

Probabilistic potential health risk quantification, hydrochemistry, driving forces of groundwater nitrate and fluoride in a typical irrigation district, Northern China

Groundwater is the foremost water source of agricultural irrigation areas in northern China. However, the problem from excessive geogenic fluoride and anthropogenic nitrate in groundwater and its potential health risks are often neglected. This paper aims to identify the health threats, water quality and hydrochemistry in Weibei Plain, northern China. A total of 50 water samples collected in May 2021 were assessed by hydrogeochemical analysis, the entropy weight water quality index method and probabilistic human health risk assessment based on Monte Carlo stochastic simulation. The results showed that the hydrochemical type of surface water and groundwater was mainly SO4·Cl–Ca·Mg type. The rock weathering and cation exchanges were found to the important processes influencing hydrochemistry. The quality of surface water was higher than that of groundwater, with Class IV and Class V groundwater samples concentrated in the northwest of the study area. The F− concentration in groundwater samples generally exceeded the drinking water standard, which mainly came from mineral dissolution affected by excessive irrigation. Nitrate pollution in groundwater has regional characteristics, mainly from agricultural activities. Long−term use of groundwater might bring risks to residents' health, because more than 65% and 23% of groundwater samples exceeded the acceptable non−carcinogenic risk limits of F− and NO3− to children, respectively. Considering the uncertainty of model parameters, children will have a probability of more than 46.9% and 12.6% to face F− and NO3− risks in groundwater. Compared with NO3−, the high concentration of F− in groundwater posed a higher threat to human health, and children faced higher risks. Compared with the deterministic method, the stochastic simulation can more accurately reflect health risks. The findings of this study can help policymakers devise strategies to ensure a safe supply of domestic water.

Extraction and Purification of Lectin from Soybean Seeds (Glycine max)

In this study, the effectiveness of the ion exchange column packed with anionic resin DEAE-Sephadex®-A-50 in purifying lectin isolated by conventional saline buffer method was investigated. After the lectin extraction, the purification efficacy of ion exchange cationic and anionic resins was compared. The purified lectin was freeze-dried to a solid state to characterize its physiochemical properties. The characterization included the presence and content of protein, sulfur, and carbohydrate, hemagglutination test, gel electrophoresis for molecular weight determination, and metal photometry for sodium content determination. The physiochemical characterization was carried out by Fourier-transfer infrared spectroscopy and X-ray diffraction studies. The test results were compared with the standard sample of soybean lectin. The purified lectin was amorphous, basic in nature, tetramer, galactose binding/N-acetylgalactosamine molecule in its sodium salt form, with a molecular weight of 120 kiloDaltons. Based on the results, the anionic resin DEAE-Sephadex®-A-50 can effectively purify lectin isolated from soybean seeds.

Nickel Hyperaccumulator Biochar Sorbs Ni(II) from Water and Wastewater to Create an Enhanced Bio-ore.

Nickel (Ni) hyperaccumulators make up the largest proportion of hyperaccumulator plant species; however, very few biochar studies with hyperaccumulator feedstock have examined them. This research addresses two major hypotheses: (1) Biochar synthesized from the Ni hyperaccumulator Odontarrhena chalcidica grown on natural, metal-rich soil is an effective Ni sorbent due to the plant's ability to bioaccumulate soluble and exchangeable cations; and (2) such biochar can sorb high concentrations of Ni from complex solutions. We found that O. chalcidica grew on sandy, nutrient-poor soil from a Minnesota mining district but did not hyperaccumulate Ni. Biochar prepared from O. chalcidica biomass at a pyrolysis temperature of 900 °C sorbed up to 154 mg g-1 of Ni from solution, which is competitive with the highest-performing Ni sorbents in recent literature and the highest of any unmodified, plant-based biochar material reported in the literature. Precipitation, cation exchange, and adsorption mechanisms contributed to removal. Ni was effectively removed from acidic solutions with initial pH > 2 within 30 min. O. chalcidica biochar also removed Ni(II) from a simulated Ni electroplating rinsewater solution. Together, these results provide evidence for O. chalcidica biochar as an attractive material for simultaneously treating high-Ni wastewater and forming an enhanced Ni bio-ore.

Assessing the pollution effect of cement dust emission on the soil quality around Ewekoro cement factory, southwestern Nigeria

This study assessed the pollution effects of cement dust emission on the soil quality around Ewekoro, southwestern Nigeria. Composite soil samples were collected at six locations from the cement factory (0 km) to a distance of 3 km outside the factory; for two consecutive years. Soil samples were also taken from a distance of 22 km after the cement factory to serve as a control. A total of 42 soil samples were collected and subjected to laboratory assays using standard procedures. Samples were analyzed for pH, organic carbon, particle size, available phosphorus (AvP), alkalinity, exchangeable cations, and heavy metals. Data collected were subjected to simple descriptive and inferential statistics using SPSS for Windows. Pollution effect was also evaluated for pollution index (PI), ecological risk index (ERI), Nemerov integrated pollution index (NIPI), and enrichment factor (EF). Results showed significantly higher levels of exchangeable cations, alkalinity, AvP, pH, Cr, Cu, Pb, and Fe in the vicinity of the cement factory than in the control site. The distribution of metals in soils around the cement factory followed the trend of Fe > Mn > Zn > Pb > Cr > Cu. The PI of metals in soil established high pollution levels for Pb and Zn. The NIPI values for Cu, Cr, and Fe showed low levels of pollution at the vicinity of the cement industry, while no pollution level was observed at the control site. NIPI revealed that Pb varied from low to moderate pollution levels across the sampling locations. The EF values of Zn and Pb were higher than 2.0, thereby suggesting emissions from anthropogenic activities, especially from the cement industry.

Enhanced photodegradation of tylosin in the presence of natural montmorillonite: Synergistic effects of adsorption and surface hydroxyl radicals

Tylosin (TYL) is a ubiquitous macrolide antibiotic which has been frequently detected in natural aqueous environment. Montmorillonite (MMT), a major component of natural suspended particles, plays essential roles in the transportation and transformation processes of various organic contaminants. This study systematically investigated the photodegradation behavior and mechanism of TYL in MMT suspensions under simulated sunlight irradiation. In the existence of 0.1 g L−1 Na-MMT, >80.8 % TYL was degraded after 8 h irradiation, which was significantly higher than that in the absence of MMT (42.5 %). Further mechanistic studies suggested that the synergistic effects including the formation of surface complex and the generation of surface hydroxyl radicals play essential roles in the accelerated TYL phototransformation. Meanwhile, other factors like exchangeable cations of MMTs, pH and ionic strength could also strongly influence the TYL photodegradation. The probable degradation pathways of TYL in MMT suspension was further proposed based on the detected intermediates and DFT calculations. Photobacterium phospherium T3 bioluminescent assay revealed that the photodegradation products of TYL have a lower acute toxicity than bulk TYL, especially in the presence of MMT. This study provides new insights for the photodegradation pathways of organic contaminants in aqueous environments, which is of great importance for assessing the fate and risk of emerging pollutants in natural surface water bodies.