Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22.076
Filtrar
1.
Food Chem ; 351: 129328, 2021 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-33647697

RESUMEN

A part of the fungicides used in foliar treatment penetrates into the soil. This study describes changes in the bioavailability of (essential) elements in soil, fructification, the amount of green biomass and the production of phenolic compounds related solely to the presence of triazoles (penconazole and cyproconazole) in soil, injected as a single compound or their mixture. The triazoles presence has substantially affected the bioavailability of Fe, Cu and Zn in soil. The amount of green biomass has significantly decreased, whereas the chlorophylls a and b have not been affected. As a potential mark of plant stress, the fruits of the treated variants are significantly bigger. The content of phenolics in tomato peel (e.g. quercetin, quercitrin, hesperidin, naringin, and chlorogenic, salicylic and p-coumaric acid) has been quantified. The biggest changes (increase/decrease) have been observed in the contents of p-coumaric and chlorogenic acid, quercetin and quercitrin.


Asunto(s)
Biomasa , Frutas/efectos de los fármacos , Frutas/crecimiento & desarrollo , Lycopersicon esculentum/efectos de los fármacos , Fenoles/metabolismo , Suelo/química , Triazoles/farmacología , Disponibilidad Biológica , Fungicidas Industriales/análisis , Fungicidas Industriales/farmacología , Lycopersicon esculentum/crecimiento & desarrollo , Lycopersicon esculentum/metabolismo , Triazoles/análisis
2.
Nat Commun ; 12(1): 1937, 2021 03 29.
Artículo en Inglés | MEDLINE | ID: mdl-33782399

RESUMEN

137Cs is a long-lived (30-year radioactive half-life) fission product dispersed globally by mid-20th century atmospheric nuclear weapons testing. Here we show that vegetation thousands of kilometers from testing sites continues to cycle 137Cs because it mimics potassium, and consequently, bees magnify this radionuclide in honey. There were no atmospheric weapons tests in the eastern United States, but most honey here has detectable 137Cs at >0.03 Bq kg-1, and in the southeastern U.S., activities can be >500 times higher. By measuring honey, we show regional patterns in the biogeochemical cycling of 137Cs and conclude that plants and animals receive disproportionally high exposure to ionizing radiation from 137Cs in low potassium soils. In several cases, the presence of 137Cs more than doubled the ionizing radiation from gamma and x-rays in the honey, indicating that despite its radioactive half-life, the environmental legacy of regional 137Cs pollution can persist for more than six decades.


Asunto(s)
Radioisótopos de Cesio/metabolismo , Miel/análisis , Plantas/metabolismo , Contaminantes Radiactivos del Suelo/metabolismo , Suelo/química , Animales , Abejas/química , Abejas/fisiología , Radioisótopos de Cesio/química , Historia del Siglo XX , Historia del Siglo XXI , Armas Nucleares/historia , Plantas/química , Polinización/fisiología , Contaminantes Radiactivos del Suelo/química , Análisis Espacio-Temporal , Estados Unidos
3.
J Vis Exp ; (168)2021 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-33645568

RESUMEN

Roots extensively interact with their soil environment but visualizing such interactions between roots and the surrounding rhizosphere is challenging. The rhizosphere chemistry of wetland plants is particularly challenging to capture because of steep oxygen gradients from the roots to the bulk soil. Here a protocol is described that effectively preserves root structure and rhizosphere chemistry of wetland plants through slam-freezing and freeze drying. Slam-freezing, where the sample is frozen between copper blocks pre-cooled with liquid nitrogen, minimizes root damage and sample distortion that can occur with flash-freezing while still minimizing chemical speciation changes. While sample distortion is still possible, the ability to obtain multiple samples quickly and with minimal cost increases the potential to obtain satisfactory samples and optimizes imaging time. The data show that this method is successful in preserving reduced arsenic species in rice roots and rhizospheres associated with iron plaques. This method can be adopted for studies of plant-soil relationships in a wide variety of wetland environments that span concentration ranges from trace-element cycling to phytoremediation applications.


Asunto(s)
Elementos , Imagenología Tridimensional/métodos , Raíces de Plantas/química , Rizosfera , Humedales , Liofilización , Oryza/anatomía & histología , Suelo/química
4.
Ecotoxicol Environ Saf ; 214: 112070, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33652361

RESUMEN

In line with sustainable development principles and in order to combat climate change, which contributes to progressive soil depletion, various solutions are being sought to use treated sewage sludge as a soil amendment to improve soil quality and enrich arable soils with adequate amounts of biogenic compounds. This review article focuses on the effects of the agricultural use of biosolids on the environment. The article reviews the existing knowledge on selected emerging contaminants in treated sewage sludge and describes the impact of these pollutants on the environment and living organisms based on 183 publications selected from over 16,000 papers on related topics published over the last ten years. This study deals not only with chemical contaminants but also genetic determinants of resistance to these compounds. Current research has questioned the agricultural use of biosolids due to the presence of mutual interactions between antibiotics, heavy metals, the genetic determinants of resistance (antibiotic resistance genes - ARGs and heavy metal resistance genes - HMRGs) and non-steroidal anti-inflammatory drugs as well as the risks associated with their transfer to the environment. This study emphasizes the need for more extensive legal regulations that account for other pollutants of environmental concern (PEC), particularly in countries where sewage sludge is applied in agriculture most extensively. Future research should focus on more effective methods of eliminating PEC from sewage sludge, especially from the sludge that is used to fertilize agricultural land, because even small amounts of these micropollutants can have serious implications for the health and life of humans and animals.


Asunto(s)
Agricultura , Aguas del Alcantarillado/química , Contaminantes del Suelo/análisis , Eliminación de Residuos Líquidos/métodos , Animales , Antibacterianos , Productos Agrícolas , Farmacorresistencia Microbiana/genética , Contaminantes Ambientales , Humanos , Metales Pesados/análisis , Suelo/química
5.
J Chromatogr A ; 1641: 461981, 2021 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-33684778

RESUMEN

Asymmetrical flow field-flow fractionation (AF4) hyphenated with inductively coupled plasma-mass spectrometry (ICP-MS) has been widely used to characterize metal containing particles. This study demonstrates the advantages of coupling AF4 with ICP-time-of-flight mass spectrometry (ICP-TOFMS) in standard and single particle modes to determine size distribution, elemental composition, and number concentration of composite particles. The coupled system was used to characterize two complex particle mixtures. The first mixture consisted of particles extracted from micro-alloyed steels with two size populations of different elemental composition. The second mixture consisted of particles extracted from soil spiked with various engineered nanoparticles (ENPs). The equivalent hydrodynamic sizes of individual micro-alloyed steel particles were up to 6 times larger than the sizes determined by single particle (sp)-ICP-TOFMS. The larger AF4 sizes were attributed to the presence of a surface coating, which is not reflected in the core size determined by sp-ICP-TOFMS. Two particle populations could not be separated by AF4 due to their broad size distributions but were resolved by sp-ICP-TOFMS using their unique elemental signatures. Multi-angle light scattering and ICP-TOFMS signals of soil suspensions increased with the spiked ENP concentrations. However, only after conducting full element screening and single particle fingerprinting by ICP-TOFMS could this increase be attributed to enhanced extraction efficiency of natural particles and the risk for false conclusions be eliminated. In this study, we describe how AF4 coupled to ICP-TOFMS can be applied to study complex samples of inorganic particles which contain organic compounds.


Asunto(s)
Fraccionamiento de Campo-Flujo/métodos , Espectrometría de Masas/métodos , Nanopartículas/química , Nitrilos/química , Tamaño de la Partícula , Dispersión de Radiación , Procesamiento de Señales Asistido por Computador , Suelo/química , Análisis Espectral , Titanio/química
6.
Ecotoxicol Environ Saf ; 214: 112049, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33647852

RESUMEN

The disposal of untreated sanitary sewage in the soil has several consequences for human health and leads to environmental risks; thus, it is necessary investigating, monitoring and remediating the affected sites. The aims of the current study are to evaluate ecotoxicological effects on Eisenia andrei earthworms exposed to soil subjected to sources of sanitary sewage discharge and to investigate whether prevention values established by the Brazilian legislation for soil quality, associated with the incidence of chemical substances in it, are satisfactory enough to assure the necessary quality for different organisms. Earthworms' behavior, reproduction, acetylcholinesterase activity, catalase, superoxide dismutase and malondialdehyde levels were evaluated. The reproduction and behavior of earthworms exposed to sanitary sewage were adversely affected. Increased superoxide dismutase and catalase activity acted as antioxidant defense mechanism. Significantly increased lipid peroxidation levels and acetylcholinesterase activity inhibition have indicated lipid peroxidation in cell membrane and neurotransmission changes, respectively. Results have confirmed that sanitary sewage induced oxidative stress in earthworms. In addition, based on biochemical data analysis, the integrated biomarker response (IBR) has evidenced different toxicity levels in earthworms between the investigated points. Finally, results have indicated that effluents released into the soil, without proper treatment, lead to contaminant accumulation due to soil saturation and it can hinder different processes and biological development taking place in the soil. In addition, the current study has shown that physical-chemical analyses alone are not enough to assess soil quality, since it is also requires adopting an ecotoxicological approach. Brazilian legislation focused on soil quality must be revised and new guiding values must be proposed.


Asunto(s)
Oligoquetos/fisiología , Contaminantes del Suelo/análisis , Animales , Antioxidantes/metabolismo , Brasil , Catalasa/metabolismo , Ecotoxicología , Contaminación Ambiental/análisis , Humanos , Malondialdehído/metabolismo , Oligoquetos/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Aguas del Alcantarillado , Suelo/química , Superóxido Dismutasa/metabolismo
7.
J Vis Exp ; (168)2021 02 10.
Artículo en Inglés | MEDLINE | ID: mdl-33645576

RESUMEN

Estimations of soil organic carbon are dependent on soil processing methods including removal of undecomposed plant material. Inadequate separation of roots and plant material from soil can result in highly variable carbon measurements. Methods to remove the plant material are often limited to the largest, most visible plant materials. In this manuscript we describe how electrostatic attraction can be used to remove plant material from a soil sample. An electrostatically charged surface passed close to dry soil naturally attracts both undecomposed and partially decomposed plant particles, along with a small quantity of mineral and aggregated soil. The soil sample is spread in a thin layer on a flat surface or a soil sieve. A plastic or glass Petri dish is electrostatically charged by rubbing with polystyrene foam or nylon or cotton cloth. The charged dish is passed repeatedly over the soil. The dish is then brushed clean and recharged. Re-spreading the soil and repeating the procedure eventually results in a diminishing yield of particulates. The process removes about 1 to 5% of the soil sample, and about 2 to 3 times that proportion in organic carbon. Like other particulate removal methods, the endpoint is arbitrary and not all free particulates are removed. The process takes approximately 5 min and does not require a chemical process as do density flotation methods. Electrostatic attraction consistently removes material with higher than average C concentration and C:N ratio, and much of the material can be visually identified as plant or faunal material under a microscope.


Asunto(s)
Compuestos Orgánicos/química , Material Particulado/análisis , Suelo/química , Electricidad Estática , Carbono/análisis , Plantas/química , Plásticos/química
8.
Ecotoxicol Environ Saf ; 213: 112042, 2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33607336

RESUMEN

Aluminum (Al) toxicity severely decreases plant growth and productivity in acidic soil globally. Ectomycorrhizal (ECM) fungi can promote host plant's Al-tolerance by acting as a physical barrier or bio-filter. However, little information is available on the role of ECM fungus on Al immobilization with respect to Al-tolerance. This present study aimed to screen a promising indigenous ECM fungus with high Al-tolerance and to understand its role in Al immobilization related to Al-tolerance. Two ECM fungal strains (Lactarius deliciosus 2 and Pisolithus tinctorius 715) isolated from forest stands in Southwest China were cultured in vitro with 0.0, 1.0 or 2.0 mM Al addition for 21 days to compare their Al accumulation and Al-tolerance. Meanwhile, fungal mycelia were incubated in 0.037 mM Al3+ solutions, and then Al3+ concentrations in the solution were determined at time 2, 5, 10, 20, 40, 60, 120, 180, and 240 min, and the Al3+ immobilization characteristics were evaluated using the pseudo-first order, pseudo-second order and intraparticle diffusion models. Results showed that 1.0 or 2.0 mM Al3+ addition significantly increased fungal biomass production by 23% or 41% in L. deliciosus 2, not in P. tinctorius 715. Fungal Al3+ concentrations in L. deliciosus 2 and P. tinctorius 715 were significantly increased by 293% and 103% under 2.0 mM than under 1.0 mM Al3+ addition. The pH values in the culture solution were significantly decreased by 0.43 after 21 d fungus growth but no changes between these two fungi under the same Al3+ addition. Fungal Al3+ immobilization showed a three-stage trend with initially a rapid rate followed a relatively slower rate until reaching equilibrium. The pseudo-second order model was the best (R2 = 0.98 and 0.99 for L. deliciosus 2 and P. tinctorius 715) to fit the experimentally observed data among the three models. Compared to P. tinctorius 715, L. deliciosus 2 also had greater intercept value, cation exchange capacity (CEC), and extracellular Al3+ proportion in fungal mycelia. Additionally, bio-concentration on Al3+, active site numbers for Al3+, boundary layer thickness, CEC, and immobilization on the cell wall in fungal mycelia were involved in ECM fungal Al-tolerance. These results show that both ECM fungi are Al-tolerant while L. deliciosus 2 is a promising indigenous ECM isolate with higher Al-tolerance in Southwest China, and they can be hence applied to the afforestation and ecological restoration in acidic soil.


Asunto(s)
Aluminio/metabolismo , Basidiomycota/fisiología , Contaminantes del Suelo/metabolismo , Agaricales , Basidiomycota/crecimiento & desarrollo , Biodegradación Ambiental , Biomasa , China , Bosques , Micelio/crecimiento & desarrollo , Micorrizas/crecimiento & desarrollo , Micorrizas/fisiología , Suelo/química , Microbiología del Suelo
9.
J Chromatogr A ; 1640: 461957, 2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33582516

RESUMEN

The objective of this work was to explore centrifugal ultrafiltration (UF) to separate and / or preconcentrate natural colloidal particles for their characterization. A soil suspension obtained by batch leaching was used as a laboratory reference sample. It was preconcentrated with concentration factors (CF) varying from 10 to 450. The dimensional analysis of the colloidal phase was carried out by Asymmetric Flow Field-Flow Fractionation (AF4)-multidetection. The colloidal masses were estimated by mass balance of the initial suspension, its concentrates and filtrates. The size-dependent distribution (expressed in gyration radius) and total colloidal mass (especially recovery), as well as chemical composition and concentration (including species partitioning between dissolved and colloidal phases) were determined to assess the effects of UF preconcentration on colloidal particles. The gyration radius of the colloidal particles recovered in these concentrated suspensions ranged from about 20 nm to over 150 nm. Neither de-agglomeration nor agglomeration was observed. However, only (64 ± 4) % (CF = 10) of the colloidal particles initially in the soil suspension were found in the recovered concentrated suspensions, and this percentage decreased as CF increased. The filter membrane trapped all other particles, mainly the larger ones. Whatever the CF, the centrifugal UF did not appear to change the dissolved-colloidal partitioning of certain species (Al, organic carbon); whereas it led to an enrichment of the colloidal phase for others (Fe, U). The enrichment rate was specific to each species (15% for Fe; 100% for U). By fitting the observed trends (i.e. conservation, depletion or enrichment of the colloidal phase in the concentrate) as a function of CF, the colloidal concentrations (total and species) were assessed without bias. This methodology offers a new perspective for determining physicochemical speciation in natural waters, with a methodology applicable for environmental survey or site remediation studies.


Asunto(s)
Coloides/química , Suelo/química , Suspensiones/química , Ultrafiltración/métodos , Uranio/análisis , Centrifugación , Fraccionamiento de Campo-Flujo , Tamaño de la Partícula
10.
Ecotoxicol Environ Saf ; 212: 111996, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-33545409

RESUMEN

Rhizosphere microbes are essential partners for plant stress tolerance. Recent studies indicate that arbuscular mycorrhizal fungi (AMF) can facilitate the revegetation of soils contaminated by heavy metals though interacting with rhizosphere microbiome. However, it is unclear how AMF affect rhizosphere microbiome to improve the growth of plant under rare earth elements (REEs) stress. AMF (Claroideoglomus etunicatum) was inoculated to maize grown in soils spiked with Lanthanum (0 mg kg-1, La0; 10 mg kg-1, La10; 100 mg kg-1, La100; 500 mg kg-1, La500). Plant biomass, nutrient uptake, REE uptake and rhizosphere bacterial and fungal community were evaluated. The results indicated that La100 and La500 decreased significantly root colonization rates and nutrition uptake (K, P, Ca and Mg content). La500 decreased significantly α-diversity indexes of bacterial and fungal community. AMF enhanced significantly the shoot and root fresh and dry weight of maize in all La treatments (except for the root fresh and dry weight of La0 and La10 treatment). For La100 and La500 treatments, AMF increased significantly nutrition uptake (K, P, Ca and Mg content) in shoot of maize by 27.40-441.77%. For La500 treatment, AMF decreased significantly shoot La concentration by 51.53% in maize, but increased significantly root La concentration by 30.45%. In addition, AMF decreased bacterial and fungal Shannon index in La0 treatment, but increased bacterial Shannon index in La500 treatment. Both AMF and La500 affected significantly the bacterial and fungal community composition, and AMF led to more influence than La. AMF promoted the enrichment of bacteria, including Planomicrobium, Lysobacter, Saccharothrix, Agrococcus, Microbacterium, Streptomyces, Penicillium and other unclassified genus, and fungi (Penicillium) in La500, which showed the function for promoting plant growth and tolerance of heavy metal. The study revealed that AMF can regulate the rhizosphere bacterial and fungal composition and foster certain beneficial microbes to enhance the tolerance of maize under La stress. Phytoremediation assisted by AMF is an attractive approach to ameliorate REEs-contaminated soils.


Asunto(s)
Hongos/crecimiento & desarrollo , Lantano/toxicidad , Micorrizas/fisiología , Rizosfera , Microbiología del Suelo , Contaminantes del Suelo/toxicidad , Zea mays/efectos de los fármacos , Bacterias/crecimiento & desarrollo , Biodegradación Ambiental , Biomasa , Glomeromycota/crecimiento & desarrollo , Lantano/análisis , Microbiota , Raíces de Plantas/química , Raíces de Plantas/microbiología , Suelo/química , Contaminantes del Suelo/análisis , Zea mays/crecimiento & desarrollo , Zea mays/microbiología
11.
Ecotoxicol Environ Saf ; 212: 112016, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-33550079

RESUMEN

The effects of Bacillus subtilis inoculation on the growth and Cd uptake of alfalfa were evaluated in this research using pot experiments, and the relevant biochemical mechanisms were first investigated by combined microbial diversity and nontarget metabolomics analyses. The results indicated that inoculation with alfalfa significantly decreased the amount of plant malondialdehyde (MDA) and improved the activities of plant antioxidant enzymes and soil nutrient cycling-involved enzymes, thereby promoting biomass by 29.4%. Inoculation also increased Cd bioavailability in rhizosphere soil by 12.0% and Cd removal efficiency by 139.3%. The biochemical mechanisms included enhanced bacterial diversity, transformed microbial community composition, regulated amounts of amino acids, fatty acids, carbohydrates, flavonoids and phenols in rhizosphere soil metabolites, and modulations of the corresponding Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. These responses were beneficial to microbial activity, nutrient cycling, and Cd mobilization, detoxification, and decontamination by alfalfa in soil. This study, especially the newly identified differential metabolites and metabolic pathways, provides new insights into mechanism revelation and strategy development in microbe-assisted phytomanagement of heavy metal-contaminated soils.


Asunto(s)
Bacillus subtilis/metabolismo , Cadmio/metabolismo , Medicago sativa/metabolismo , Rizosfera , Contaminantes del Suelo/metabolismo , Bacillus subtilis/crecimiento & desarrollo , Biodegradación Ambiental , Biodiversidad , Biomasa , Cadmio/análisis , Medicago sativa/microbiología , Metabolómica , Suelo/química , Microbiología del Suelo , Contaminantes del Suelo/análisis
12.
Nat Commun ; 12(1): 810, 2021 02 05.
Artículo en Inglés | MEDLINE | ID: mdl-33547289

RESUMEN

The understanding of soil organic matter (SOM) dynamics has considerably advanced in recent years. It was previously assumed that most SOM consisted of recalcitrant compounds, whereas the emerging view considers SOM as a range of polymers continuously processed into smaller molecules by decomposer enzymes. Mainstreaming this new paradigm in current models is challenging because of their ill-adapted framework. We propose the C-STABILITY model to resolve this issue. Its innovative framework combines compartmental and continuous modeling approaches to accurately reproduce SOM cycling processes. C-STABILITY emphasizes the influence of substrate accessibility on SOM turnover and makes enzymatic and microbial biotransformations of substrate explicit. Theoretical simulations provide new insights on how depolymerization and decomposers ecology impact organic matter chemistry and amount during decomposition and at steady state. The flexible mathematical structure of C-STABILITY offers a promising foundation for exploring new mechanistic hypotheses and supporting the design of future experiments.


Asunto(s)
Celulosa/metabolismo , Lignina/metabolismo , Consorcios Microbianos/fisiología , Modelos Estadísticos , Suelo/química , Azúcares/metabolismo , Biodegradación Ambiental , Biotransformación , Simulación por Computador , Lípidos/química , Proteínas/metabolismo , Microbiología del Suelo
13.
Ecotoxicol Environ Saf ; 213: 112061, 2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33636466

RESUMEN

Maize seed treatment with chemicals to control underground pests is a common agricultural practice, but inappropriate use of insecticides poses a considerable threat to plant development and soil nontarget organisms. In this study, the availability of tetraniliprole seed dressing to control the black cutworm Agrotis ipsilon (Lepidoptera: Noctuidae) in the maize seeding stage and its safety to earthworms (Eisenia fetida) were investigated. The selective toxicity (ST) of tetraniliprole between E. fetida and A. ipsilon was greater than 4000. No significant adverse effect of tetraniliprole seed treatment on the germination of maize seeds was observed at concentrations of 2.4-9.6 g a.i. /kg seed. Compared with the untreated control, seed treatment with tetraniliprole at 9.6 g a.i. /kg seed greatly reduced the percentage of damaged plants from 88.73% to 26.67%, and achieved the highest control effect of 69.91%. Tetraniliprole of 2.4 g a.i. /kg seed can effectively inhibit A. ipsilon until 14 days after seed germination, with the lowest mortality rate of 44.44%. During the entire exposure period, the maximum residual concentration of tetraniliprole detected in the soil (5.86 mg/kg) was considerably lower than the LC50 value of tetraniliprole to E. fetida (>4000 mg/kg). According to the low-tier risk assessment, the highest risk quotient (RQ) of tetraniliprole seed treatment to earthworms at test concentrations was 2.8 × 10-3, which was evaluated as acceptable. This study provided data support for tetraniliprole seed treatment to control underground pests in maize fields.


Asunto(s)
Insecticidas/toxicidad , Pirazoles/toxicidad , Piridinas/toxicidad , Contaminantes del Suelo/toxicidad , Tetrazoles/toxicidad , Animales , Insecticidas/análisis , Mariposas Nocturnas , Oligoquetos , Pirazoles/análisis , Piridinas/análisis , Medición de Riesgo , Semillas/química , Suelo/química , Contaminantes del Suelo/análisis , Tetrazoles/análisis , Zea mays
14.
Ecotoxicol Environ Saf ; 208: 111723, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396054

RESUMEN

Combining biochar (BR) with other immobilizing amendments has additive effects on Pb immobilization and been recognized to be effective for the restoration of Pb polluted soils. However, the impacts of different proportions between BR and a highly efficient Pb immobilizing agent called "magnesium potassium phosphate cement (MC)" have never been earlier investigated. This work aimed to investigate the consequences of BR and MC alone and their mixtures of 25:75, 50:50, and 75:25 ratios on Pb bioavailability, Pb immobilization index (Pb-IMMi), and enzymatic activities in Pb polluted soil. Furthermore, amendments effects on Pb distribution in spinach, growth, antioxidant capacity, biochemical, and nutritional spectrum were also investigated. We found that MC alone performed well to immobilize Pb in soil and reducing its distribution in shoots, but was less efficient to improve soil enzymatic activities and plant attributes. Conversely, the application of BR alone stimulated soil enzymatic activities, plant growth, and quality but was less effective to immobilize Pb in soil and reducing shoot Pb concentrations. The combinations of BR and MC of various ratios showed variable results. Interestingly, the most promising outcomes were obtained with BR50%+MC50% treatment which resulted in enhanced Pb-IMMi (73%), activities of soil enzymes, plant growth and quality, and antioxidant capacity, compared to control. Likewise, significant reductions in Pb concentrations in shoots (85%), roots (78%), extractable Pb (73%) were also obtained with BR50%+MC50% treatment, compared to control. Such outcomes point towards a cost-effective approach for reducing Pb uptake by the plants via using MC and BR at a 50:50 ratio.


Asunto(s)
Carbón Orgánico/química , Plomo/farmacocinética , Compuestos de Magnesio/química , Fosfatos/química , Compuestos de Potasio/química , Contaminantes del Suelo/farmacocinética , Spinacia oleracea/metabolismo , Disponibilidad Biológica , Materiales de Construcción , Restauración y Remediación Ambiental , Plomo/análisis , Nyctaginaceae/química , Suelo/química , Contaminantes del Suelo/análisis , Spinacia oleracea/crecimiento & desarrollo
15.
J Agric Food Chem ; 69(2): 756-766, 2021 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-33404229

RESUMEN

An effective and sensitive method for the determination of isopyrazam (IZM) isomers (syn-IZM and anti-IZM) and their metabolites (syn545364 and syn545449) in tomato and soil by ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed in the present study. The method showed excellent linearities (R2 = 0.999) at 0.005-5 mg/L. The recoveries were 92.0-107%, and the relative standard deviation (RSD) values were lower than 9.40% in tomato and soil matrices at 0.01, 0.1, and 10 mg/kg. The limits of detection (LODs) of the four compounds ranged from 6.88 × 10-5 to 2.70 × 10-4 mg/kg, while the limits of quantification (LOQs) ranged from 2.20 × 10-4 to 9.20 × 10-4 mg/kg. The storage stability test results showed that syn-IZM, anti-IZM, syn545449, and syn545364 were stable in tomato at -20 °C within 36 weeks, and the maximum degradation rates were 16.0, 12.0, 7.10, and 12.0%, respectively. The field dissipation test results showed that the half-lives of syn-IZM in tomato and soil were 2.60-10.2 and 13.6-33.0 days, respectively, while the half-lives of anti-IZM in soil were 21.7-46.2 days, and no residues of anti-IZM were detected in tomato. The terminal residue test results showed that the residue of syn-IZM and anti-IZM in tomato ranged from <0.0100-0.490 to <0.0100-0.0850 mg/kg. The present results showed that anti-IZM degraded faster than syn-IZM in tomato and soil, and had a lower residue level in tomato.


Asunto(s)
Lycopersicon esculentum/química , Norbornanos/química , Residuos de Plaguicidas/química , Pirazoles/química , Contaminantes del Suelo/química , Cromatografía Líquida de Alta Presión , Contaminación de Alimentos/análisis , Frutas/química , Isomerismo , Suelo/química , Espectrometría de Masas en Tándem
16.
Ecotoxicol Environ Saf ; 211: 111904, 2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33453639

RESUMEN

This original research was performed to assess the possible effects of solid biochar (25 g biochar kg-1 soil) and biochar-based nanocomposites (BNCs) of magnesium oxide (25 g BNC-MgO kg-1 soil), manganese oxide (25 g BNC-MnO biochar kg-1 soil) and combined use of these nanocomposites (12.5 g BNC-MgO + 12.5 g BNC-MnO kg-1 soil) on soil properties and salinity (non-saline, 6 and 12 dSm-1) tolerance of safflower plants (Carthamus tinctorius L.). Application of biochar, particularly BNCs increased the pH and cation exchange capacity of soil, and the contents of water, potassium, calcium, magnesium, manganese, chlorophyll (a & b), nutrients uptake, water use efficiency and plant growth. Sodium adsorption ratio (SAR), exchangeable sodium percentage (ESP) of soil, sodium absorption rate of plants and osmolyte production (soluble carbohydrates and proteins, proline and glycine betaine) under 6 and 12 dSm-1 salinities were decreased by biochar and BNCs treatments. Sodium sorption capacity of BNCs was much higher than the solid biochar, which reflected the superiority of BNCs in decreasing sodium uptake by plants. The combined application of BNC-MgO + BNC-MnO proved to be the preferable treatment for decreasing salt toxicity in safflower. Biochar and BNCs improved root and shoot growth by lowering SAR, ESP, sodium absorption rate of plants and osmotic stress under saline conditions. These results conclude that BNCs can enrich the plant cells with nutrients, increase the nutrients absorption rate and maintain the plant tissue water content at an optimum level to improve plant growth under salt stress.


Asunto(s)
Carbón Orgánico , Magnesio/química , Manganeso/química , Adsorción , Carthamus tinctorius/metabolismo , Clorofila , Iones/metabolismo , Magnesio/metabolismo , Manganeso/metabolismo , Nanocompuestos , Óxidos/metabolismo , Potasio/metabolismo , Salinidad , Estrés Salino , Tolerancia a la Sal , Sodio/metabolismo , Suelo/química , Contaminantes del Suelo/metabolismo
17.
Ecotoxicol Environ Saf ; 211: 111899, 2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33453641

RESUMEN

The presence of microplastics and arsenic in soil can endanger crop growth; therefore, their effects on the properties of rhizosphere soil should be evaluated. Large (10-100 µm) and small (0.1-1 µm) polystyrene (PSMP) and polytetrafluorethylene (PTFE) particles were added to soil with different arsenic concentrations (1.4, 24.7, and 86.3 mg kg-1) to investigate the combined effect of microplastics and arsenic pollution on rice rhizosphere soil. After the addition of PSMP and PTFE, pH, arsenic (V) and arsenic (III) in the soil were observed to decrease. The interaction of arsenic with PSMP and PTFE resulted in this phenomenon, leading to a decrease of arsenic bioavailability in the soil. PSMP, PTFE, and arsenic reduced the abundance of Proteobacteria, increased the abundance of Chloroflexi and Acidobacteria, and inhibited soil urease, acid phosphatase, protease, dehydrogenase, and peroxidase activity via affecting the tertiary structure of the enzyme. PSMP, PTFE, and arsenic also reduced the available nitrogen and phosphorus content in the soil. Arsenic increased the soil organic matter content, whereas PSMP and PTFE reduced the organic matter content. Furthermore, microplastics inhibited the effects of arsenic on the microbial and chemical properties of the rhizosphere soil. This study revealed the effects of microplastic and arsenic pollution on rice rhizosphere microorganisms and nutrients, and elucidated the mechanism by which these pollutants retard crop growth in the designed growth medium.


Asunto(s)
Arsénico/toxicidad , Microplásticos/toxicidad , Contaminantes del Suelo/toxicidad , Arsénico/análisis , Contaminación Ambiental , Nitrógeno , Nutrientes , Oryza/crecimiento & desarrollo , Plásticos , Rizosfera , Suelo/química , Microbiología del Suelo , Contaminantes del Suelo/análisis
18.
Ecotoxicol Environ Saf ; 211: 111914, 2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33454593

RESUMEN

Bioremediation of Cd contaminated environments can be assisted by plant-growth-promoting bacteria (PGPB) enabling plant growth in these sites. Here a gram-negative Burkholderia contaminans ZCC was isolated from mining soil at a copper-gold mine. When exposed to Cd(II), ZCC displayed high Cd resistance and the minimal inhibitory concentration was 7 mM in LB medium. Complete genome analysis uncovered B. contaminans ZCC contained 3 chromosomes and 2 plasmids. One of these plasmids was shown to contain a multitude of heavy metal resistance determinants including genes encoding a putative Cd-translocating PIB-type ATPase and an RND-type related to the Czc-system. These additional heavy metal resistance determinants are likely responsible for the increased resistance to Cd(II) and other heavy metals in comparison to other strains of B. contaminans. B. contaminans ZCC also displayed PGPB traits such as 1-aminocyclopropane-1-carboxylate deaminase activity, siderophore production, organic and inorganic phosphate solubilization and indole acetic acid production. Moreover, the properties and Cd(II) binding characteristics of extracellular polymeric substances was investigated. ZCC was able to induce extracellular polymeric substances production in response to Cd and was shown to be chemically coordinated to Cd(II). It could promote the growth of soybean in the presence of elevated concentrations of Cd(II). This work will help to better understand processes important in bioremediation of Cd-contaminated environment.


Asunto(s)
Adaptación Fisiológica/fisiología , Burkholderia/fisiología , Cadmio/toxicidad , Contaminantes del Suelo/toxicidad , Biodegradación Ambiental , Cadmio/metabolismo , Ácidos Indolacéticos , Metales Pesados/análisis , Minería , Desarrollo de la Planta , Suelo/química , Microbiología del Suelo , Contaminantes del Suelo/análisis , Soja/metabolismo
19.
Ecotoxicol Environ Saf ; 211: 111843, 2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33465626

RESUMEN

Geothermal energy is a low-pollution energy source. However, air, soil, and water near geothermal plants may be affected by their operation. One of the largest geothermal energy sources in the world, Cerro Prieto, has a capacity of 720 MW and is located in northwest Mexico near an agricultural area. The abstracted geothermal fluids, which are enriched with arsenic (As), boron (B), lead (Pb), cadmium (Cd), and other heavy metals, are either reinjected into the aquifer or sent to an evaporation pond located in the geothermal plant. Because spills have occurred in other geothermal zones, it is important to evaluate the effect of those contaminants on the soils of the surrounding area and their possible infiltration into shallow groundwater. To that aim, soils (one chromic Vertisol and two calcic Regosols) from three sites near the Cerro Prieto Geothermal Plant were sampled to evaluate their behavior regarding As, Pb, and B retention. Batch experiments were carried out using the soils as the sorbent and geothermal water from three geothermal production wells as the sorbate. Raw water concentrations in each well were as follows: As: 0.2442 mg/L, 0.2774 mg/L, and mg/L; B: 18.409 mg/L, 13.5075 mg/L, and 16.646 mg/L; and Pb: 0.22 mg/L, 0.13 mg/L, and 0.26 mg/L. The physicochemical characteristics of the soils were determined and compared to the experimental results. A good adjustment of the chromic Vertisol sample to Freundlich isotherms was observed for As (r2 > 0.9), followed by Pb (r2 = 0.61), and B (r2 > 0.5). As retention also showed a good adjustment to the Langmuir model (r2 > 0.9). The retention followed the order Pb >As ≫B in one of the two calcic Regosols, while the other only retained Pb ≫ As. Cationic exchange capacity; clay minerals; carbonate; organic matter; and iron, aluminum, and manganese amorphous and crystalline oxides influenced the soils' retention capacities. Irrigation with geothermal water could not imply a toxicity risk to plants grown in the chromic Vertisol soil due to its high Pb and As sorption capacity. Pb concentration could not be a toxicity issue in the calcic Regosols for the same reason, but As and B could be. B would be a hazard to vegetables and water due to its low or lack of retention in the three soils and also for its possible infiltration into shallow groundwater used for irrigation in the area. This study highlights the importance of maintaining adequate operation and control of the disposal of geothermal fluids in geothermal plants.


Asunto(s)
Arsénico/análisis , Boro/análisis , Agua Subterránea/química , Plomo/análisis , Contaminantes del Suelo/análisis , Agricultura , Cadmio/química , Metales Pesados/análisis , México , Suelo/química
20.
J Chromatogr A ; 1638: 461882, 2021 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-33453657

RESUMEN

This paper reported a headspace gas chromatography (HS-GC) for the determination of denitrifying enzyme activity in soil samples. It was based on measuring the NO2 signal in a set of closed/air-free vials containing soil samples that incubated at the designated conditions. The results showed that the method has a good measurement precision (RSD < 5.0%) and reasonable accuracy for determining the denitrifying enzyme activity in soil samples. It is simple and efficient, and very suitable to be used in batch sample analysis.


Asunto(s)
Cromatografía de Gases/métodos , Desnitrificación , Enzimas/metabolismo , Suelo/química , Calibración , Dióxido de Nitrógeno/análisis , Tamaño de la Muestra , Factores de Tiempo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...