Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 42.837
Filtrar
1.
Toxicol Lett ; 375: 69-76, 2023 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-36610527

RESUMEN

The objectives of the study were to simulate low-level Pb exposure scenario in an animal model and to examine reproductive adverse effects. Based on obtained data, we have performed Benchmark dose (BMD)-response modelling. Male Wistar rats were randomized in seven groups (n = 6): one control and six treated with: 0.1, 0.5, 1, 3, 7, and 15 mg Pb/kg body weight, daily for 28 days by oral gavage. The rats were sacrificed and the blood and testes were used for further analysis of testosterone levels in serum, testicular essential metal levels and histological analysis. The Pb treatment led to a dose-dependent decrease of serum testosterone levels with a negative trend (BMDI 0.17-6.13 mg Pb/kg). Increase of Zn (dose-dependent, BMDI 0.004-19.7 mg Pb/kg) and Cu and a decrease of Mn testicular levels were also detected with unscathed histology of the testes. The presented results might be used in further evaluation of the point of departure in human health risk assessment for Pb.


Asunto(s)
Benchmarking , Plomo , Humanos , Ratas , Masculino , Animales , Ratas Wistar , Plomo/toxicidad , Testículo , Testosterona
2.
Physiol Rep ; 11(1): e15530, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36597186

RESUMEN

Metabolic Syndrome (MetS) raises cardiovascular disease risk. Extracellular vesicles (EVs) have emerged as important mediators of insulin sensitivity, although few studies on vascular function exist in humans. We determined the effect of insulin on EVs in relation to vascular function. Adults with MetS (n = 51, n = 9 M, 54.8 ± 1.0 years, 36.4 ± 0.7 kg/m2 , ATPIII: 3.5 ± 0.1 a.u., VO2 max: 22.1 ± 0.6 ml/kg/min) were enrolled in this cross-sectional study. Peripheral insulin sensitivity (M-value) was determined during a euglycemic clamp (40 mU/m2 /min, 90 mg/dl), and blood was collected for EVs (CD105+, CD45+, CD41+, TX+, and CD31+; spectral flow cytometry), inflammation, insulin, and substrates. Central hemodynamics (applanation tonometry) was determined at 0 and 120 min via aortic waveforms. Pressure myography was used to assess insulin-induced arterial vasodilation from mouse 3rd order mesenteric arteries (100-200 µm in diameter) at 0.2, 2 and 20 nM of insulin with EVs from healthy and MetS adults. Adults with MetS had low peripheral insulin sensitivity (2.6 ± 0.2 mg/kg/min) and high HOMA-IR (4.7 ± 0.4 a.u.) plus Adipose-IR (13.0 ± 1.3 a.u.). Insulin decreased total/particle counts (p < 0.001), CD45+ EVs (p = 0.002), AIx75 (p = 0.005) and Pb (p = 0.04), FFA (p < 0.001), total adiponectin (p = 0.006), ICAM (p = 0.002), and VCAM (p = 0.03). Higher M-value related to lower fasted total EVs (r = -0.40, p = 0.004) while higher Adipose-IR associated with higher fasted EVs (r = 0.42, p = 0.004) independent of VAT. Fasting CD105+ and CD45+ derived total EVs correlated with fasting AIx75 (r = 0.29, p < 0.05) and Pb (r = 0.30, p < 0.05). EVs from MetS participants blunted insulin-induced vasodilation in mesenteric arteries compared with increases from healthy controls across insulin doses (all p < 0.005). These data highlight EVs as potentially novel mediators of vascular insulin sensitivity and disease risk.


Asunto(s)
Vesículas Extracelulares , Resistencia a la Insulina , Síndrome Metabólico , Adulto , Humanos , Animales , Ratones , Insulina , Estudios Transversales , Plomo/metabolismo , Obesidad/metabolismo , Vesículas Extracelulares/metabolismo
3.
Mar Environ Res ; 184: 105872, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36621131

RESUMEN

This study recompiled a national dataset to characterize the pollution level and health risk of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) in oysters along the coastal areas of China. Results showed that the median concentrations of Cd, Cu, Pb and Zn in nationwide oysters were 5.5, 335, 1.3 and 1280 mg/kg dry weight, respectively. Generally, oysters from the north coasts presented lower metal pollution and higher quality than those from the south. The regional characteristics of trace metals in oysters might be contributed by the interspecific differences. Nationally, the noncarcinogenic risk posed by these four metals in oysters was relatively low, with the risk only occurring in a few hotspots such as the Pearl River Estuary and the Jiulong River Estuary. However, more attention should be paid to the carcinogenic risk of Cd, and priority should be given to formulating control measures to mitigate Cd pollution.


Asunto(s)
Metales Pesados , Ostreidae , Oligoelementos , Contaminantes Químicos del Agua , Humanos , Animales , Metales Pesados/análisis , Cadmio , Bioacumulación , Plomo , Contaminantes Químicos del Agua/análisis , China , Monitoreo del Ambiente/métodos
4.
Molecules ; 28(2)2023 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-36677888

RESUMEN

The main objectives of this study are to synthesize a new solid-supported ionic liquid (SSIL) that has a covalent bond between the solid support, i.e., activated silica gel, with thiosalicylate-based ionic liquid and to evaluate the performance of this new SSIL as an extractant, labelled as Si-TS-SSIL, and to remove Pb(II) ions from an aqueous solution. In this study, 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium thiosalicylate ([MTMSPI][TS]) ionic liquid was synthesized and the formation of [MTMSPI][TS] was confirmed through structural analysis using NMR, FTIR, IC, TGA, and Karl Fischer Titration. The [MTMSPI][TS] ionic liquid was then chemically immobilized on activated silica gel to produce a new thiosalicylate-based solid-supported ionic liquid (Si-TS-SSIL). The formation of these covalent bonds on Si-TS-SSIL was confirmed by solid-state NMR analysis. Meanwhile, BET analysis was performed to study the surface area of the activated silica gel and the prepared Si-TS-SSIL (before and after washing with solvent) with the purpose to show that all physically immobilized [MTMSPI][TS] has been washed off from Si-TS-SSIL, leaving only chemically immobilized [MTMSPI][TS] on Si-TS-SSIL before proceeding with removal study. The removal study of Pb(II) ions from an aqueous solution was carried out using Si-TS-SSIL as an extractant, whereby the amount of Pb(II) ions removed was determined by AAS. In this removal study, the experiments were carried out at a fixed agitation speed (400 rpm) and fixed amount of Si-TS-SSIL (0.25 g), with different contact times ranging from 2 to 250 min at room temperature. The maximum removal capacity was found to be 8.37 mg/g. The kinetics study was well fitted with the pseudo-second order model. Meanwhile, for the isotherm study, the removal process of Pb(II) ions was well described by the Freundlich isotherm model, as this model exhibited a higher correlation coefficient (R2), i.e., 0.99, as compared to the Langmuir isotherm model.


Asunto(s)
Líquidos Iónicos , Contaminantes Químicos del Agua , Líquidos Iónicos/química , Plomo , Gel de Sílice/química , Adsorción , Agua , Iones/química , Cinética , Contaminantes Químicos del Agua/química
5.
Molecules ; 28(2)2023 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-36677741

RESUMEN

Arabica-coffee and Theobroma-cocoa agroindustrial wastes were treated with NaOH and characterized to efficiently remove Pb(II) from the aqueous media. The maximum Pb(II) adsorption capacities, qmax, of Arabica-coffee (WCAM) and Theobroma-cocoa (WCTM) biosorbents (qmax = 303.0 and 223.1 mg·g-1, respectively) were almost twice that of the corresponding untreated wastes and were higher than those of other similar agro-industrial biosorbents reported in the literature. Structural, chemical, and morphological characterization were performed by FT-IR, SEM/EDX, and point of zero charge (pHPZC) measurements. Both the WCAM and WCTM biosorbents showed typical uneven and rough cracked surfaces including the OH, C=O, COH, and C-O-C functional adsorbing groups. The optimal Pb(II) adsorption, reaching a high removal efficiency %R (>90%), occurred at a pH between 4 and 5 with a biosorbent dose of 2 g·L-1. The experimental data for Pb(II) adsorption on WACM and WCTM were well fitted with the Langmuir-isotherm and pseudo-second order kinetic models. These indicated that Pb(II) adsorption is a chemisorption process with the presence of a monolayer mechanism. In addition, the deduced thermodynamic parameters showed the endothermic (ΔH0 > 0), feasible, and spontaneous (ΔG0 < 0) nature of the adsorption processes studied.


Asunto(s)
Cacao , Coffea , Contaminantes Químicos del Agua , Café , Plomo , Espectroscopía Infrarroja por Transformada de Fourier , Contaminantes Químicos del Agua/química , Concentración de Iones de Hidrógeno , Termodinámica , Agua/química , Cinética , Adsorción
6.
Molecules ; 28(2)2023 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-36677817

RESUMEN

Heavy metals represent a large category of pollutants. Heavy metals are the focus of researchers around the world, mainly due to their harmful effects on plants. In this paper, the influence of copper, cadmium, manganese, nickel, zinc and lead, present in soil in different concentrations (below the permissible limit, the maximum permissible concentration and a concentration higher than the maximum permissible limit) on lettuce (Lactuca sativa L.) was evaluated. For this purpose, the authors analyzed the variation of photosynthetic pigments, total polyphenols, antioxidant activity and the elemental content in the studied plants. The experimental results showed that the variation of the content of biologically active compounds, elemental content and the antioxidant activity in the plants grown in contaminated soil, compared to the control plants, depends on the type and concentration of the metal added to the soil. The biggest decrease was recorded for plants grown in soil treated with Ni I (-42.38%) for chlorophyll a, Zn II (-32.92%) for chlorophyll b, Ni I (-40.46%) for carotenoids, Pb I (-40.95%) for polyphenols and Cu III (-29.42%) for DPPH. On the other hand, the largest increase regarding the amount of biologically active compounds was registered for Mn I (88.24%) in the case of the chlorophyll a, Mn I (65.56%) for chlorophyll b, Pb I (116.03%) for carotenoids, Ni III (1351.23%) for polyphenols and Ni III (1149.35%) for DPPH.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Lechuga , Clorofila A , Antioxidantes/farmacología , Plomo , Metales Pesados/toxicidad , Metales Pesados/análisis , Suelo/química , Carotenoides , Contaminantes del Suelo/análisis
7.
Anal Chim Acta ; 1243: 340827, 2023 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-36697180

RESUMEN

CRISPR-based detection was often based on the target preamplification to realize the high sensitivity. Here, we prepared a CRISPR-Cas12a system for the colorimetric detection of lead ion (Pb2+) based on the assistance of DNAzyme and nanozyme instead of preamplification. The recognition between GR-5 DNAzyme and Pb2+ could trigger the CRISPR-Cas12a system. MnO2 nanozymes connected with magnetic beads through single stranded DNA were prepared as the colorimetric signal probes and catalyst of CRISPR-Cas12a system for the strong oxidase-like activity inducing the color change of 3,3',5,5'-tetramethylbenzidine. The nanozyme-catalysed CRISPR-Cas12a system could be used to detect Pb2+ through the color change with high specificity and sensitivity. The linear range of this approach was 0.8 nM-2500 nM, with a limit of detection of 0.54 nM. This method was applied for the detection of the Pb2+ in food samples indicating good accuracy and anti-interference ability.


Asunto(s)
Técnicas Biosensibles , ADN Catalítico , Sistemas CRISPR-Cas , Colorimetría , Plomo , Compuestos de Manganeso , Óxidos
8.
J Hazard Mater ; 446: 130691, 2023 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-36608576

RESUMEN

The toxicity of metals to microorganisms is highly correlated with the type of metal used. However, the differences in the resistance mechanisms of filamentous fungi to multiple metals remain unclear. In this study, we investigated the responses of Aspergillus niger to three toxic metals, i.e., Pb2+, Cd2+, and Cu2+. Fungal growth and metabolism indices showed that A. niger had a higher tolerance to Pb2+ (>1000 mg L-1) than to Cu2+ (300 mg L-1) and Cd2+ (50 mg L-1). An appropriate Pb2+ concentration (<500 mg L-1) stimulated fungal growth and metabolic activity, whereas Cd2+ and Cu2+ stress showed continuously negative influences on fungal physiological parameters, such as biomass and secretion of oxalic acid. A. niger responded to Pb stress by constructing a new border layer around its cell wall. This pathway was also confirmed using RNA-seq analysis, i.e., the gene encoding cell wall α-1,3-glucan synthase was upregulated. This upregulation subsequently promoted the production of polysaccharides, which are the main components that support fungal cell walls. In contrast, the expression of genes encoding both AAA family ATPase and efflux pump antibiotic resistance proteins for Cd2+ and Cu2+ was significantly downregulated. Therefore, these findings elucidated the relatively complete fungal responses to different metal stresses.


Asunto(s)
Aspergillus niger , Cadmio , Aspergillus niger/genética , Aspergillus niger/metabolismo , Cadmio/toxicidad , Cadmio/metabolismo , Plomo/toxicidad , Plomo/metabolismo , Ácido Oxálico/metabolismo
9.
Molecules ; 28(2)2023 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-36677560

RESUMEN

The present study investigated the isotopic and elemental profile (by IRMS and ICP-MS) of edible egg parts (29 egg whites and 29 yolks) mainly collected from Romania. In order to differentiate the egg white and yolk coming from different hen rearing systems (backyard and barn), Partial Least Square-Discriminant Analysis (PLS-DA) models were developed. The models' accuracies for the discrimination according to the hen growing system were 96% for egg white and 100% for egg yolk samples, respectively. Elements that proved to have the highest discrimination power for both egg white and yolk were the following: δ13C, Li, B, Mg, K, Ca, Mn, Fe, Co, Zn, Rb, Sr, Mo, Ba, La, Ce, and Pb. Nevertheless, the important compositional differentiation, in terms of essential mineral content, between the edible egg parts (egg white and egg yolk) were also pointed out. The estimated daily intake (EDI), the target hazard quotient (THQ) for Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Cd, Pb, and As, as well as the hazard index (HI) were used to assess non-carcinogenic human health risks from egg consumption. The obtained results showed no noticeable health risks related to egg consumption for humans from the point of view of the potentially toxic metals.


Asunto(s)
Huevos , Metales Pesados , Oligoelementos , Animales , Femenino , Pollos , Monitoreo del Ambiente , Plomo/análisis , Metales Pesados/análisis , Minerales/análisis , Medición de Riesgo , Análisis Espectral , Oligoelementos/análisis , Huevos/análisis
10.
Environ Monit Assess ; 195(2): 323, 2023 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-36692645

RESUMEN

The current study investigated the concentrations, possible sources, toxicity, and ecological risk of eight heavy metal(loid)s (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) and sixteen priority polycyclic aromatic hydrocarbons (PAHs) in surface sediments in the port of Prahovo (Danube, Serbia). Among the examined HMs, the most abundant was Cu (38.3 mg/kg), followed by Zn. The Σ16PAHs concentrations ranged from 25 to 112.5 µg/kg, with 4-ring PAHs (17.3 µg/kg) being the most dominant in the study area. The mean and maximum values of HMs and PAHs obtained in this study were below the national regulatory limits and within environmental criteria. Particularly significant correlations between As, Cd, Cr, Ni, Pb, Zn, 5-, 6-ring PAHs, as well as between Pb and Hg, indicated their similar anthropogenic sources, pathways, and adsorption mechanisms. These findings were confirmed by cluster analysis and principal component analysis. Diagnostic ratios demonstrated that contamination in inner port stations was characterized by pyrogenic sources, while PAHs of petrogenic origin prevailed in samples near the port entrance. The mean ERM quotient (mERMq), toxic risk index (TRI), and toxic equivalent quotient (TEQ) were also calculated to assess the toxicity of the investigated HMs and PAHs in sediments. Positive matrix factorization suggested four potential sources as the main components of sediment contamination, whereas the risk assessment indicated a low or relatively insignificant risk of adverse biological effects from the combined toxicity of HMs and PAHs for the entire study area.


Asunto(s)
Mercurio , Metales Pesados , Hidrocarburos Policíclicos Aromáticos , Contaminantes Químicos del Agua , Hidrocarburos Policíclicos Aromáticos/análisis , Cadmio/análisis , Plomo/análisis , Monitoreo del Ambiente , Metales Pesados/análisis , Mercurio/análisis , Medición de Riesgo , Sedimentos Geológicos/análisis , Contaminantes Químicos del Agua/análisis , China
11.
BMC Public Health ; 23(1): 31, 2023 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-36604667

RESUMEN

BACKGROUND: There are few thorough studies on the extent and inter-element relationships of heavy metal contamination in printing factory workers, especially in developing countries. The objective of this study was to determine the levels of eight heavy metals, including arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), cobalt (Co), lead (Pb), mercury (Hg), and manganese (Mn), in urine and scalp hair of printing industry workers, and assess inter-element correlations. METHODS: We examined a total of 85 urine samples and 85 scalp hair samples (3 cm hair segments taken from near the scalp) in 85 printing workers from a printing house in Bangkok, Thailand. We used an interviewer-administered questionnaire about participants' printing techniques, work characteristics, and work environment. Urine and scalp hair samples were analyzed for levels of each element using the inductively coupled plasma optical emission spectrometry (ICP-OES) technique. RESULTS: As, Cd, Cr, Ni, Pb were detected in urine with the geometric mean concentration range of 0.0028-0.0209 mg/L, and Hg, Pb, Ni, Cd, Co, Mn, Cr were detected in hair samples (0.4453-7.165 mg/kg dry weight) of printing workers. The geometric mean Ni level was significantly higher in the urine of production line workers than back-office personnel (0.0218 mg/L vs. 0.0132 mg/L; p = 0.0124). The other elements did not differ significantly between production line and back-office workers in either urine or hair. There was also a strong, statistically significant positive correlation between Ni and Co levels in hair samples of workers (r = 0.944, p < 0.0001). CONCLUSIONS: Average concentrations of most of the metals in urine and hair of printing workers were found to be above the upper reference values. The significantly higher concentrations of Ni in production line workers might be due to more exposure to printed materials. A strong inter-element correlation between Ni and Co in hair samples can increase stronger health effects and should be further investigated. This study reveals possible dependencies and impact interactions of heavy metal exposure in printing factory workers.


Asunto(s)
Arsénico , Mercurio , Metales Pesados , Humanos , Cadmio/análisis , Tailandia , Plomo/análisis , Monitoreo del Ambiente/métodos , Metales Pesados/análisis , Manganeso/análisis , Níquel/análisis , Arsénico/análisis , Mercurio/análisis , Cabello/química
12.
Artículo en Inglés | MEDLINE | ID: mdl-36613124

RESUMEN

Heavy metals pollution of water resources is an emerging concern worldwide and seeks immediate attention. Date palm waste was transformed into biochar (BC), which was further modified through Fe-intercalation for the production of magnetic biochar (Fe-BC) in this study. The produced BC and Fe-BC were analyzed for chemical, proximate, surface, and elemental composition. The efficiency of the produced adsorbents to decontaminate the water from Cd2+ and Pb2+ ions was investigated through kinetics and an isotherm adsorption batch trial. Kinetics adsorption data fit well with the pseudo-second order and power function model, while equilibrium data were described well with the Langmuir and Freundlich isotherms. The maximum adsorption capacity as shown by the Langmuir model was the highest for Fe-BC for both Cd2+ (48.44 mg g-1) and Pb2+ (475.14 mg g-1), compared with that of BC (26.78 mg g-1 Cd2+ and 160.07 mg g-1 Pb2+). Both materials showed higher removal of Pb (36.34% and 99.90% on BC and Fe-BC, respectively) as compared with Cd (5.23% and 12.28% on BC and Fe-BC, respectively) from a binary solution. Overall, Fe-BC was more efficient in adsorbing both of the studied metals from contaminated water. The application of Fe-BC resulted in 89% higher adsorption of Cd2+ and 197% higher adsorption of Pb2+ from aqueous media as compared to BC. Kinetics and isotherm models as well as SEM-EDS analysis of the post-adsorption adsorbents suggested multiple adsorption mechanisms including chemisorption, pore-diffusion, and electrostatic interactions.


Asunto(s)
Phoeniceae , Contaminantes Químicos del Agua , Cadmio/análisis , Plomo , Carbón Orgánico/química , Agua , Adsorción , Contaminantes Químicos del Agua/análisis , Cinética
13.
Artículo en Inglés | MEDLINE | ID: mdl-36613194

RESUMEN

Layered double hydroxide (LDH)-doped chicken-manure biochar (CMB) with long-term stability was synthesized to immobilize Pb/Cd. MgAl-Cl-LDH-doped CMB (MHs) showed prominent long-term oxidation resistance and the least biodegradation sensitivity. Efficient Pb/Cd adsorption was observed on MHs, and the maximum adsorption capacities of Pb(II)/Cd(II) reached 1.95 mmol/g and 0.65 mmol/g, respectively. Precipitation and isomorphous substitution were identified as the key adsorption mechanisms, which formed highly stable Pb/Cd species (PbAl-CO3-LDH, Pb3(OH)2CO3, CdAl-Cl-LDH and CdCO3). Pb(II) and Cd(II) precipitated with CO32- in MHs; meanwhile, Mg(II) and Ca(II) in LDH layers were substituted by Pb(II) and Cd(II) respectively. Therefore, MHs had the potential for long-term stability of Pb/Cd. Moreover, complexation and electrostatic adsorption also contributed to the Pb/Cd immobilization to a certain extent. When 5% MHs (w/w) was applied to Pb/Cd contaminated smelting site soils, the soil pH increased from 5.9 to 7.3. After applying MHs for 25 d, the content of bioavailable Pb(II) and Cd(II) decreased by 98.8% and 85.2%, respectively, and the content of soluble Pb and Cd dropped by 99.5% and 96.7%. This study paves the way for designing a novel LDH doped CMB as efficient Pb/Cd immobilizers for smelting site soils.


Asunto(s)
Cadmio , Contaminantes del Suelo , Animales , Cadmio/química , Estiércol , Pollos , Plomo , Hidróxidos , Carbón Orgánico/química , Suelo/química , Contaminantes del Suelo/química
14.
Environ Monit Assess ; 195(2): 318, 2023 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-36680599

RESUMEN

The purpose of this work was to study the patterns of Zn, Cu, and Pb distribution in soil aggregates of various size fractions. Materials were Calcic Chernozems and Urbic Technosol of the Rostov agglomeration. Soil samples were passed through sieves with different mesh sizes (dry sieving). For the study, particle size fractions of > 10, 7-5, 5-3, 2-1, and < 0.25 mm were sampled, where the total forms of Zn, Cu, and Pb were examined by means of the X-ray fluorescence method. In the Zn content in both Calcic Chernozems and Urbic Technosol peaks in < 0.25-mm particle size fractions, the concentration decreases as particle size grows. Calcic Chernozems display Cu concentrations in mid-size soil particles of 2-1 and 5-3 mm. In Urbic Technosols, the lowest Cu concentration is typically found in particle size fractions of > 10 mm. Pb in Calcic Chernozems is concentrated in mid-size soil aggregates of 2-1 and 5-3 mm. However, Urbic Technosols tend to accumulate silt-fraction lead (< 0.25 mm). A higher zinc concentration in silt-fraction aggregates found in Urbic Technosols in comparison to Calcic Chernozems highlights the anthropogenic origin of a considerable part of this element's soil pool. Excessively high lead content in UR (urbic) horizons leads to the structure degradation and, consequently, to a transformed overall trend of HM distribution across the soil profile in general.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Cobre/análisis , Zinc/análisis , Plomo , Monitoreo del Ambiente , Suelo/química , Contaminantes del Suelo/análisis , Metales Pesados/análisis
15.
Environ Monit Assess ; 195(2): 317, 2023 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-36680597

RESUMEN

Information on spatial distribution and potential sources of heavy metals in agricultural lands is very important for human health and food safety. In this study, pollution degree of lead (Pb), cadmium (Cd), and nickel (Ni) in Yüksekova Plain, located on the border in the southeastern part of Turkey, was evaluated by geoaccumulation index (Igeo), modified contamination factor (mCdeg), and Nemerow pollution index (PINemerow) combined with spatial autocorrelation using deep learning algorithms. A total of 304 soil samples were collected from two different depths (0-20 and 20-40 cm) in the study area, which covered 17.5 thousand ha land. Covariates were determined for spatial distribution models of Pb, Cd, and Ni by factor analysis (FA). Spatial distribution models for surface soils were developed using pedovariables (silt, sand, clay lime, organic matter, electrical conductivity, pH, Ca, and Na) determined by the FA and Igeo and mCdeg values by artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) models. The estimation success of models for different depths was assessed by root mean square error (RMSE), mean absolute percent error (MAPE), and Taylor diagrams. The RMSE and MAPE values showed a strong correlation between heavy metal contents and the covariates. The RMSE values of ANN-Ni0-20, ANN-Ni20-40, ANN-Pb0-20, ANN-Cd0-20, and ANN-Cd20-40 models (0.01240, 0.07257, 0.0039, 0.00045, 0.00044, and 0.04607, respectively) confirmed the success of the models. Likewise, the MAPE values between 0.2 and 8.5% indicated that all models were very good predictors. In addition, the Taylor diagrams showed that the estimation performance of ANFIS and ANN models are compatible. The IgeoNi and IgeoPb values in both models at both depths indicated that strongly to extremely polluted (4-5) areas are quite high in the study area, while the IgeoCd values revealed that unpolluted areas are widespread. The mCdeg index value showed a moderate to high contamination at the first depth, while very high contamination at the second depth in most of the study area. Spatial distribution of PINemerow revealed that moderate pollution (2-3) is common in both soil depths of the study area. The PINemerow of subsurface layer was between 0.91 and 1 (warning limit class) in a small part of the study area. The results showed that vertical mobility of heavy metals is closely related to pedovariables. In addition, the ANN and ANFIS models are capable of exhibiting the heterogeneity in the spatial distribution pattern of high variation in the data. Thus, the locations with extreme contamination have been accurately determined. The pollution indices calculated considering the commonly used international reference values revealed that heavy metal pollution in some part of the study area reached the detrimental levels for human health and food safety. The results suggested that the pollution indices were more successful than simple heavy metal concentrations in interpreting the pollution risk levels. High-resolution spatial information reported in this study can help policy makers and authorities to reduce heavy metal emissions of pollutants or, if possible, to eliminate the pollution.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Humanos , Suelo/química , Cadmio/análisis , Inteligencia Artificial , Plomo/análisis , Monitoreo del Ambiente/métodos , Contaminantes del Suelo/análisis , Metales Pesados/análisis , Níquel/análisis , Análisis Espacial , Medición de Riesgo , China
16.
Bull Environ Contam Toxicol ; 110(2): 44, 2023 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-36680693

RESUMEN

Long- term application of marginal quality water accumulated significant amount of pollutant into the soil. It reduces soil health parameters, and crop yield and their quality. In this regards, graded application of pressmud (PM), i.e. 0, 2.5, 5 and 10 g/kg was applied on lead (Pb) contamination level (0, 100, 150, 300 mg/kg) and evaluated interaction effect on plant nutrients uptake by spinach. Analytical data showed that increasing the PM levels enhanced the macro (phosphorus, potassium, sulphur) and micro-nutrient (zinc, copper, manganese, iron) concentration into the soil. Whereas, increasing the level of Pb significantly (p ≤ 0.05) reduced the P, K and S nutrient concentration and uptake pattern by spinach crop. Increasing PM levels (control to 10 g/kg soil) improved P, K and S by 46.99, 98.96 and 76.79%, respectively in soil. This study is useful to formulate management strategies for minimizing Pb contamination in the food chain by the application of PM mostly in peri-urban areas.


Asunto(s)
Plomo , Contaminantes del Suelo , Manganeso , Zinc/análisis , Nutrientes , Suelo , Contaminantes del Suelo/análisis
17.
J Chem Phys ; 158(3): 034506, 2023 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-36681631

RESUMEN

In this paper, we investigate prenucleation and heterogeneous nucleation in the liquid Pb/solid Al system as an example of systems with large lattice misfit using molecular dynamics simulation. Solid Pb and Al have a large positive lattice misfit (f) of 18.2% along the densely packed [110] direction. This study reveals that prenucleation occurs at 600 K (an undercooling of 15 K), and a 2-dimensional (2D) ordered structure forms at the interface with a coincidence site lattice (CSL) between the first Pb and first Al layers. The CSL accommodates the major part of the f, and only a small residual lattice misfit (fr) of 1.9% remains. The formation of the CSL transforms the original substrate into a considerably potent nucleant, where the first Pb layer becomes the new surface layer of the substrate. At an undercooling of about 22 K, nucleation proceeds by merging 2D ordered structure through structural templating: the second Pb layer is epitaxial to the CSL Pb layer, the third Pb layer largely accommodates the fr, and the fourth Pb layer is a nearly perfect crystalline plane. Further analysis indicates that the interface with the CSL has a lower interfacial energy than with a cube-to-cube orientation relationship. For the first time, we established that the CSL was an effective mechanism to accommodate the f for systems with a large positive misfits. Heterogeneous nucleation is governed not by a single mechanism (misfit dislocations in Turnbull's model), but instead by various mechanisms depending on f. This study sheds new light on the atomistic mechanism of heterogeneous nucleation.


Asunto(s)
Plomo , Simulación de Dinámica Molecular
18.
J Mol Model ; 29(2): 52, 2023 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-36689026

RESUMEN

METHODS: The intermolecular interactions between the heavy-atom analogues of acetylene T2H2 (T = Si, Ge, Sn, Pb) and HCN have been investigated by theoretical calculations at the CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVDZ level. RESULTS: The global energy minimum of T2H2 is the butterfly structure A, and another energy minimum is the planar structure B. Both structures A and B exhibit the dual behavior when binding with HCN. The various hydrogen bond (HB), dihydrogen bond (DB) and tetrel bond (TB) complexes can be found according to the MEP maps of T2H2. One TB and three HB complexes formed between structure A and HCN can be located for Si2H2 and Ge2H2. One TB, two HB and one DB complexes formed between structure A and HCN can be located for Sn2H2 and Pb2H2. Four TB and one HB complexes formed between structure B and HCN can be located for all the T2H2. The geometries and binding strengths of the complexes are compared and analyzed. CONCLUSIONS: The interactions in these complexes are generally weak, and the interaction energies of these complexes range from -0.53 to -8.23 kcal/mol. The interaction energies of the TB complexes are larger than those of the corresponding HB and DB complexes for structure A···HCN systems. The relative binding strength of the four TB complexes exhibits different order for different structure B···HCN systems, which is consistent with the MEP maps of the isolated monomers.


Asunto(s)
Acetileno , Plomo , Modelos Moleculares , Hidrógeno , Termodinámica
19.
Inorg Chem ; 62(3): 1069-1074, 2023 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-36622078

RESUMEN

Compounds constructed by mixed anions are widely favorable for their diverse crystal structures and physical performances. Here, two lead phosphite halides, Pb2Cl2(HPO3)(H2O) (1) and Pb3Br2(HPO3)2 (2), were obtained by facile hydrothermal reactions. Both compounds crystallize in the space group Pnma. 1 exhibits a 3D structure composed of HPO3 units, PbCl4O3 pentagonal bipyramids, and PbO3 pyramids. 2 also shows a 3D framework built by HPO3 units, PbO2Br4 octahedron, PbO5 and PbO3Br2 square pyramids. By introducing halogen anions to the lead phosphite system, 1 and 2 show enhanced birefringences of 0.083 and 0.072 at 1064 nm, respectively, compared with 0.023@1064 nm for Pb2(HPO3)2. In this work, syntheses, crystal structures, optical properties, and theoretical calculation results have been studied in detail.


Asunto(s)
Fosfitos , Plomo , Birrefringencia
20.
Bull Environ Contam Toxicol ; 110(1): 40, 2023 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-36627388

RESUMEN

Predictive models were generated to evaluate the degree to which nine metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were absorbed by the leaves, stems and roots of forage sorghum in growing media comprising soil admixed with poultry manure concentrations of 0, 10, 20, 30 and 40 g/kg. The data revealed that the greatest contents of the majority of the metals were evident in the roots rather than in the stems and leaves. A bioaccumulation factor (BAF) < 1 was calculated for Cr, Fe, Ni, Pb and Zn; BAF values for Co, Cu, Mn and Cd were 3.99, 2.33, 1.44 and 1.40, respectively, i.e., > 1. Translocation factor values were < 1 for all metals with the exception of Co, Cr and Ni, which displayed values of 1.20, 1.67 and 1.35 for the leaves, and 1.12, 1.23 and 1.24, respectively, for the stems. The soil pH had a negative association with metal tissues in plant parts. A positive relationship was observed with respect to plant metal contents, electrical conductivity and organic matter quantity. The designed models exhibited a high standard of data precision; any variations between the predicted and experimentally observed contents for the nine metals in the three plant tissue components were nonsignificant. Thus, it was concluded that the presented predictive models constitute a pragmatic tool to establish the safety from risk to human well-being with respect to growing forage sorghum when cultivating media fortified with poultry manure.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Sorghum , Animales , Humanos , Suelo/química , Estiércol , Metales Pesados/análisis , Aves de Corral , Cadmio , Plomo , Contaminantes del Suelo/análisis , Monitoreo del Ambiente
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...