Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 29.918
Filtrar
1.
Environ Monit Assess ; 192(4): 234, 2020 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-32170528

RESUMO

Competitive sorption and desorption of Cd2+, Pb2+, and Hg2+ onto riverbank and sediment samples of an area impacted by pyritic residue in a Southern Brazilian catchment were evaluated. Although these ions are considered poorly mobile, a new approach has been proposed to assess their behavior and associated risk. In this sense, factorial design and three-dimensional surface methodology are proposed to describe the competitive sorption behavior of the metal ion in the environmental matrix, as well as an innovative mobilization factor (MF) to describe the desorption rate from the integration of the normalized difference of sorption-desorption fluorescence peaks. Sorption was carried out with a central composite factorial design (23) to estimate simultaneous effects of independent variables. Three-dimensional surface analysis indicated increasing Cd2+ equilibrium concentration (Ceq) with Hg2+ and Pb2+ initial concentration (Ci), showing synergistic effect and low Cd2+ affinity to the solid phase. Statistical analysis presented [Formula: see text] as a significant variable for cadmium and lead dynamics, although [Formula: see text] was also significant for Hg2+ releasing to the liquid phase. After integrating the sorption and desorption fluorescence peaks, the MF for Cd2+, Pb2+, and Hg2+ was around 0.2, 0.5, and 0.1 in riverbank sediment, and 0.3, 0.9, and 0.1 in sediment, respectively. Hence, consistent ion mobilization along the river was observed, with Pb2+ mobilizing 9 and 6 times more than Hg2+ and Cd2+, respectively. The transport of ions such as Pb2+ and Hg2+, usually considered immobile, has indeed occurred, causing contamination through the watershed and increasing environmental risk. Graphical Abstract A new approach to determine toxic metal mobilization factor in a river catchment.


Assuntos
Cádmio , Monitoramento Ambiental , Metais Pesados/análise , Adsorção , Brasil , Cádmio/análise , Metais , Movimentos da Água
2.
Zhonghua Yu Fang Yi Xue Za Zhi ; 54(3): 289-293, 2020 Mar 06.
Artigo em Chinês | MEDLINE | ID: mdl-32187934

RESUMO

Objective: To understand the levels of Pb, Cd, As, Hg, Mn, and Se in maternal and umbilical cord blood, and to explore the transplacental transfer efficiency (TTE). Methods: From September 2010 to December 2013, a total of 773 pregnant women and their newborns (Laizhou Bay Birth Cohort) were recruited from a second grade hospital in the south bank of Laizhou Bay, Bohai, Shandong Province. According to different detection methods, the six measured elements are classified into three groups including the Hg measurement group (595 mother-newborn pairs), the Pb measurement group (534 mother-newborn pairs), and the Cd, As, Mn and Se measurement group (244 mother-newborn pairs). The demographic characteristics of pregnant women and their newborns were obtained by the questionnaire. The concentrations of elements in maternal and umbilical cord blood were detected and the TTE of each element (elemental concentration in cord blood/elemental concentration in maternal blood) was calculated. The correlation of elements between maternal and cord blood was analyzed using Spearman's rank correlation coefficient. Results: The mean±SD of maternal age, gestational week and newborn birth weight of 773 mother-infant pairs were (28.34±4.50) years, (39.47±1.39) weeks and (3 419.47±497.39) g respectively. The median concentrations of Pb, Cd, As, Hg, Mn and As in maternal and cord blood were 31.12 and 30.02, 1.19 and 0.47, 8.05 and 6.03, 0.69 and 1.26, 100.70 and 105.55, 127.25 and 115.00 µg/L, respectively. The TTE of Pb, Cd, As, Hg, Mn, and Se was 0.98, 0.41, 0.73, 1.73, 0.96 and 0.91, respectively. Pb, Cd, Hg, Mn, and Se showed a significant positive correlation between maternal blood and cord blood, with Spearman correlation coefficients of 0.397, 0.298, 0.698, 0.555, and 0.285 (all P values<0.001). Conclusion: Each element was commonly detected in maternal blood and cord blood. The TTE of Hg was the highest.


Assuntos
Cádmio/sangue , Sangue Fetal/química , Sangue Fetal/metabolismo , Chumbo/sangue , Manganês/sangue , Troca Materno-Fetal , Mercúrio/sangue , Selênio/sangue , Cordão Umbilical/química , Biomarcadores/análise , Biomarcadores/sangue , Feminino , Humanos , Recém-Nascido , Gravidez , Oligoelementos/análise , Oligoelementos/sangue , Cordão Umbilical/irrigação sanguínea
3.
Environ Monit Assess ; 192(4): 222, 2020 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-32146527

RESUMO

The determination of trace metal contents directly from a solid sample is a trend in modern atomic spectrometry. The aim of this study was to develop an analytical method for the routine determination of Cd in lichens using solid sampling graphite furnace atomic absorption spectrometry (SS-GF-AAS). For the determination of Cd, the temperature program of the graphite furnace was optimized using a mixed matrix modifier (Pd + Mg (NO3)2 + Triton X-100). The limit of detection and the limit of quantification were 0.9 µg/kg and 3 µg/kg, respectively. The analytical method for Cd determination in the plant matrix was verified by the analysis of certified reference materials of lichens, seaweed, and rye grass. The developed procedure was applied to the study of Cd distribution in thalli of Usnea antarctica lichen from James Ross Island, Antarctica. The SS-GF-AAS analytical method is particularly suited for use in environmental studies and plant physiology (the microanalysis of anatomical structures).


Assuntos
Cádmio , Poluentes Ambientais , Grafite , Líquens , Regiões Antárticas , Cádmio/análise , Monitoramento Ambiental , Poluentes Ambientais/análise , Ilhas , Líquens/química , Espectrofotometria Atômica
4.
Environ Monit Assess ; 192(3): 155, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32006114

RESUMO

Quantification of the contributions from traffic source to arable roadside soil heavy metal loadings is a challenge. The contribution depends on: traffic intensity, road type and distance from the road. At a field scale (3.9 ha), 720 topsoil samples were taken. The aim of the study was to monitor and assess the impact of regional/local roads with various conditions of traffic and period of use on the distribution of Cd, Zn, Pb and Cu in the arable roadside topsoil in their vicinity. PCA indicated the occurrence of two main gradients of 11 environmental elements influencing the distribution of heavy metals in the soils of the neighbouring land. The first gradient was associated mainly with the distance from the edge of the road. The second gradient was associated with the degree of contamination of the soils and with the road type, defined by the traffic volume and period of being use. Anova reviled lack of influence of the factors for Cu contents. Unlike Cu, for Cd, Pb and Zn, the significant impact was observed for both factors and interactions between them. The concentrations of Cd, Pb and Zn, regardless of the distance from the road were 0.21-0.58 mg Cd kg-1 d.m., 13.60-41.96 mg Pb kg-1 d.m. and 40.31-63.97 mg Zn kg-1 d.m. In case of increasing distance from the road, generally the contents of Pb, Zn and Cd contents were decreasing. However, only in the case the oldest and carrying the highest traffic road was a clear, statistically significant differences noted for following distances from the road on the content of Cd, Pb and Zn. Analysis of spread gave trend curves, for Pb, Cd and Zn they were parabolas. The curves let reduce sapling distances to 65 m, 45 and 47 m for Cd, Pb and Zn, respectively.


Assuntos
Metais Pesados , Poluentes do Solo , Cádmio , Cobre , Monitoramento Ambiental , Chumbo , Metais Pesados/análise , Solo , Poluentes do Solo/análise , Emissões de Veículos , Zinco
5.
Environ Monit Assess ; 192(3): 200, 2020 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-32107644

RESUMO

The objective of this study was to characterize exposures to metals using biological samples collected on socioeconomically disadvantaged black pregnant women. We obtained 131 anonymous urine samples provided by black pregnant women visiting a Medicaid-serving prenatal clinic in Houston, TX, from March 27, 2017 to April 11, 2017. We analyzed urine samples for 15 metals including cadmium (Cd), arsenic (As), lead (Pb), and nickel (Ni) and for creatinine and cotinine. We found that median concentrations of zinc (Zn), selenium (Se), and aluminum (Al) among black pregnant women in this study were 1.5 to 3 times higher than levels reported among a cohort of well-educated non-Hispanic white pregnancy planners. We also observed elevated levels of urinary Cd and antimony (Sb) as compared with those reported for a nationally representative sample of adult women in the USA. Based on the results of an exploratory factor analysis, potential sources of metal exposures in this population may arise in home environments or be due to diet, industrial and natural sources, or traffic.


Assuntos
Metais Pesados , Gestantes , Populações Vulneráveis , Adulto , Arsênico/urina , Cádmio/urina , Monitoramento Ambiental , Feminino , Humanos , Metais Pesados/urina , Gravidez , Fatores Socioeconômicos , Texas
6.
Sci Total Environ ; 713: 136650, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32019026

RESUMO

Remediation of Cd pollution in sediments is crucial for the safety of aquatic environments and human health. In this study, four effective, common, and low-cost remediation materials (zeolite, sepiolite, red mud (RM), and biochar (BC)) loaded with nanoscale zero-valent iron (nZVI) and themselves were employed to immobilize Cd in sediments. The effects of different materials on sediment properties, immobilization effectiveness, bacterial communities, enzyme activities, and dissolved organic matter (DOM) were investigated. Results showed that sediment properties were significantly changed by the addition of immobilization materials (P < 0.05). The geochemical fraction analysis showed that the labile Cd was partially transformed to the stable fraction after immobilization, with an 11-47% decrease in the acid-soluble fraction and a 50-1000% increase in the residual fraction. The Cd immobilization effectiveness peaked at the nZVI/RM and nZVI/BC treatments, and the Cd toxicity characteristic leaching procedure (TCLP) leachabilities decreased by 42% and 44%, respectively. The modified materials were more effective for immobilizing Cd than the raw materials owing to the presence of nZVI, and the Cd TCLP leachabilities with the modified materials decreased by 15%-22% compared with the raw material treatments. Immobilization-driven reduction of bioavailable Cd enhanced the richness and diversity of bacterial communities and enzyme activities. Moreover, the immobilization treatment promoted the Fe(III)-reducing process by increasing the Fe(III)-reducing bacteria (e.g. Geobacteraceae, Bacillus, and Clostridium), which are conducive to Cd immobilization. Additionally, the DOM composition presented more autogenetic characteristics in treated groups. BC (nZVI/BC) can be selected as the priority material for Cd immobilization in sediments due to higher immobilization effectiveness and lower adverse effects on sediments.


Assuntos
Carvão Vegetal , Cádmio , Recuperação e Remediação Ambiental , Ferro
7.
Sci Total Environ ; 713: 136694, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32019035

RESUMO

The relative ease with which cadmium (Cd) in agricultural soils can transfer to crop plants can pose a potential health risk to consumers. However, efforts to predict and mitigate these risks are often confounded by the various factors that influence metal accumulation in the edible plant parts. The aim of this work was to identify key drivers that determine Cd concentrations in spinach leaves, potato tubers, onion bulbs and wheat grain grown in commercial horticultural operations across New Zealand (NZ). Paired soil and plant samples (n = 147) were collected from farms across different NZ growing regions. Cadmium concentrations in the edible parts were measured and four different tests were used to examine the potential bioavailability of soil Cd: pseudo-total and porewater concentrations, 0.05 M Ca(NO3)2-extraction and diffusive gradients in thin-films (DGT). Information on a range of soil and climatic variables was also collected. The methods' ability to represent Cd concentrations in the plant parts was assessed through single and multiple regression analysis that considered the different variables and the farm locations. Soil Cd concentrations determined by the different tests were positively related to plant concentrations and there were clear regional differences between these relationships. The Ca(NO3)2 extraction predicted over 76% of the variability in Cd concentrations in onion bulbs and spinach leaves, while DGT and porewater Cd provided the best estimates for potato tubers and wheat grains, respectively, once regional differences were considered, along with certain environmental and soil variables. The results show that certain soil and environmental factors can be a key influence for determining Cd accumulation in the edible parts of some plants and that regional differences are important for modulating the extent to which this occurs. These effects should be considered when trying to mitigate the potential risks arising from Cd in agricultural soils.


Assuntos
Solo , Cádmio , Nova Zelândia , Cebolas , Poluentes do Solo , Solanum tuberosum , Spinacia oleracea , Triticum
8.
Chemosphere ; 244: 125535, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32050336

RESUMO

The present study examined the effects of waterborne cadmium (Cd) exposure on ionic balance and ionocyte density in developing zebrafish (Danio rerio) (0-4 days post-fertilization). Fish exposed to 1 or 10 µg Cd/L exhibited an increase in whole body Cd level. Exposure to 10 µg Cd/L also significantly reduced whole body content of Ca2+, but not other major ions (e.g., Na+, K+ and Mg2+). Such reduction was accompanied by a decrease in the density of Ca2+-transporting ionocytes, the Na+/K+-ATPase-rich cells (NaRCs). However, the densities of other ionocyte subtypes (e.g., Na+-transporting ionocytes) remained unchanged after exposure to 10 µg Cd/L. The potential interactive effects between water chemistry and Cd exposure on ionocyte density were examined further in Cd-exposed larvae acclimated to different water NaCl or Ca2+ levels. The results demonstrated that NaRC density increased in fish acclimated to low Ca2+ water, presumably increasing Ca2+ uptake for maintaining Ca2+ homeostasis. However, Cd exposure completely abolished the increased NaRC density in low water Ca2+ environments. The increased NaRCs over development was also reduced in Cd-exposed larvae. In conclusion, our study suggested that Cd exposure reduces the density of NaRCs and suppresses the compensatory regulation of NaRCs during acclimation to low water Ca2+ level. These inhibitory effects by Cd exposure ultimately disrupt Ca2+ balance in the early life stages of zebrafish.


Assuntos
Cádmio/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/fisiologia , Animais , Transporte Biológico , Homeostase , Íons , Larva/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/metabolismo
9.
Chemosphere ; 244: 125548, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32050343

RESUMO

Wheat (Triticum aestivum L.) cultivation in cadmium (Cd) polluted soil is a core concern to food quality and food security all over the world. Cadmium toxicity is mainly associated with a Cd influx from contaminated soils to human via grain consumption. Organic amendments are widely used for Cd immobilization and enhancement in plant growth, but the residual effects of these amendments are mostly unknown. The present study addressed the long-term effects of organic amendments in contaminated soils by evaluating their residual effects on 3rd crop (wheat) in the sequence. Initially six organic amendments viz. rice husk biochar (RHB), wheat-straw biochar (WSB), cotton-stick biochar (CSB), poultry manure (PM), press mud (PrMd) and farm manure (FM) were applied once at a rate of 2% in Cd (50 mg kg-1) contaminated soil with wheat-rice rotation. After the harvest of wheat and rice crops, wheat (Var. Galaxy) was again grown in the same pots. Results revealed that plants grown under Cd stress (without any amendment) contain more tissue (root, shoot and grain) and soil AB-DTPA extractable Cd. The soil amended with RHB has shown lowest AB-DTPA extractable Cd (69% lower than control). Similarly, RHB application has significantly reduced wheat root, shoot and grain Cd concentrations compared to control and other amendments. Results have confirmed the effectiveness of RHB residual contents as an active amendment for restriction of Cd in non-bioavailable pool of soil and better growth and yield of wheat.


Assuntos
Cádmio/metabolismo , Poluentes do Solo/metabolismo , Triticum/metabolismo , Disponibilidade Biológica , Cádmio/análise , Carvão Vegetal , Produtos Agrícolas , Grão Comestível/química , Esterco , Oryza/crescimento & desenvolvimento , Solo , Poluentes do Solo/análise , Triticum/crescimento & desenvolvimento
10.
Bioresour Technol ; 303: 122853, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32044646

RESUMO

In this study, competitive adsorption behaviour and mechanisms of Cd2+, Ni2+ and NH4+ by fresh and artificially ageing biochars produced from rice straw at 400 and 700 °C (RB400, RB700, HRB400 and HRB700) were investigated. Cd2+ competed with Ni2+ and NH4+ for the overlapped adsorption sites on the biochars. For Cd2+ and Ni2+ adsorption, cation exchange (Qci) and mineral co-precipitation (Qcp) were the primary mechanisms for the low-temperature and high-temperature biochars, respectively. However, the other potential mechanisms (Qco) made the greatest contributions to NH4+ adsorption (>60%). Cd2+ and Ni2+ competition increased the proportions of mineral co-precipitation (Qcp) and other potential mechanisms (Qco) but decreased that of cation exchange (Qci) mechanism. Biochar ageing increased the contribution of surface complexation (Qcf) mechanism, especially for the low-temperature biochars. This study indicated that biochar aging and types and states of adsorbates should be considered when biochars were applied to remove contaminants.


Assuntos
Compostos de Amônio , Oryza , Adsorção , Cádmio , Carvão Vegetal , Níquel
11.
Bioresour Technol ; 303: 122886, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32046940

RESUMO

Five heavy metals namely, arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb) and mercury (Hg) are carcinogenic and show toxicity even at trace amounts, posing threats to environmental ecology and human health. There is an emerging trend of employing microalgae in phycoremediation of heavy metals, due to several benefits including abundant availability, inexpensive, excellent metal removal efficiency and eco-friendly nature. This review presents the recent advances and mechanisms involved in bioremediation and biosorption of these toxic heavy metals utilizing microalgae. Tolerance and response of different microalgae strains to heavy metals and their bioaccumulation capability with value-added by-products formation as well as utilization of non-living biomass as biosorbents are discussed. Furthermore, challenges and future prospects in bioremediation of heavy metals by microalgae are also explored. This review aims to provide useful insights to help future development of efficient and commercially viable technology for microalgae-based heavy metal bioremediation.


Assuntos
Arsênico , Metais Pesados , Microalgas , Biodegradação Ambiental , Cádmio , Cromo , Humanos
12.
Bioresour Technol ; 303: 122963, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32050124

RESUMO

Algae has potential to remediate heavy metals. However, the physiological responses of live algae to heavy metals are not well studied. In this study, the physiological responses of Microcystis aeruginosa to zinc (Zn) and cadmium (Cd) ions and its ability to accumulate ions were investigated. Low concentrations (<0.1 mg/l) of Zn and Cd had little influence on algal growth and physiological processes, whereas concentrations above 0.1 mg/l increased the esterase activity (from 42.5% to 621.9%), superoxide dismutase activity (from 12.8% to 45.4%), and malondialdehyde content (from 18.2% to 103.9%), and dramatically inhibited the cell division (from 12.6% to 70.0%) and photosynthetic performance (from 7.1% to 53.1%) of M. aeruginosa. The accumulation of Zn or Cd ions by M. aeruginosa increased exponentially with the initial concentration of metallic ions. Collectively, these findings reveal that M. aeruginosa has considerable potential in the remediation of freshwater lakes with heavy metal contamination during cyanobacterial blooms, where metallic ions are lower than 0.1 mg/l.


Assuntos
Metais Pesados , Microcystis , Biodegradação Ambiental , Cádmio , Zinco
13.
Bioresour Technol ; 300: 122708, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31926474

RESUMO

Microbially-aged hydrochar were prepared to investigate how aging affected their ability to remove Cd2+ from aqueous solutions. Based on aging time in an anaerobic fermenter, four samples were produced: HC, M20-HC, M40-HC, and M60-HC. Results indicated increases in specific surface area, pH, and negative charge on hydrochar surface with aging process. Also, there were a decrease in O/C and an increase in surface functional groups, such as -COOH. The adsorption experiments confirmed the positive correlation between aging time and adsorption performance. The 60-day-aged M60-HC treatment displayed the maximum adsorption capacity, which was 3.8 times higher than that of HC. The Langmuir and pseudo-second-order kinetic equations fitted well with isothermal and kinetic data, respectively. Thermodynamic study indicated that Cd2+ adsorption is dominated by chemisorption. This study showed that microbial aging process is an effective and promising measure to improve hydrochar adsorption capacity for Cd2+.


Assuntos
Cádmio , Poluentes Químicos da Água , Adsorção , Carvão Vegetal , Concentração de Íons de Hidrogênio , Cinética , Termodinâmica
14.
J Environ Manage ; 258: 110020, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31929061

RESUMO

Metals that contaminate soil are one of the major problems seriously affecting sustainable agriculture worldwide. Cadmium (Cd) toxicity to agricultural crops is a global problem. Mobility of Cd in contaminated soil can be minimized by the amendment of soil passivators which will ultimately reduce its movement from soil to plants. A pot study was performed to evaluate the impact of sepiolite from 1% to 5% on Cd solubility and its accumulation in spinach tissues. Soil pH, Cd fractionation, Cd accumulation in spinach tissue and Cd adsorption mechanism were determined. Results were recorded that soil pH was increased from 0.3 to 1.0 units with the increasing rate of sepiolite from 1% to 5%. Similarly, Cd contents in acid soluble phase was decreased by 42.8% and increased in residual phase by 35.8% at 5% rate, relative to control. Moreover, the significant reduction in Cd uptake by spinach shoots and roots was occurred by 26.2% and 30.6% at 5% rate, respectively. Furthermore, the maximum Cd adsorption capacity 37.35 mg g-1 was recorded at 5% rate relative to control. The analysis of FTIR, XRD and SEM also confirm the ability of sepiolite for Cd polluted soil restoration and thereby, reduces its phytoavailability in polluted soil to alleviate food security challenges.


Assuntos
Cádmio , Poluentes do Solo , Agricultura , Silicatos de Magnésio , Solo , Spinacia oleracea , Águas Residuárias
15.
J Environ Manage ; 258: 110038, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31929071

RESUMO

Heavy metals are classified as persistent pollutants owing to their nature of bioaccumulation and affect human life and environment, even in minor concentrations. Divalent Cadmium (Cd2+) is one of the heavy metal pollutants that are highly toxic. The present study investigates the novel application of maghemite nanoparticles coated Bacillus subtilis for the removal of Cd2+ ions from its aqueous solution by batch adsorption studies. Surface characterization of the biosorbent done by Scanning Electron Microscope (SEM) and the presence of maghemite nanoparticle coat was confirmed. Parameters like pH, initial metal ion concentration, contact time, and temperature that affect the biosorption of cadmium ions are analyzed, and the equilibrium adsorption capacity expressed as a function of each of the parameters. The mechanism of biosorption was studied by plotting adsorption isotherms, and it follows pseudo-second-order kinetics. Thermodynamic studies showed the process to be spontaneous and endothermic. At optimum conditions of pH 4, 30 °C, 120 rpm, maximum removal percentage of 83.5%, which accounts for an equilibrium adsorption capacity of 32.6 mg/g of biosorbent. There was a recovery of 76.4% of the biosorbent after adsorption studies. Based on the adsorptive capacity and good recovery of the biosorbent, maghemite coated Bacillus subtilis proves to be an efficient adsorbent for the removal of Cd2+ ions from its aqueous solution.


Assuntos
Nanopartículas , Poluentes Químicos da Água , Adsorção , Bactérias , Cádmio , Compostos Férricos , Concentração de Íons de Hidrogênio , Cinética , Temperatura Ambiente , Termodinâmica
16.
Environ Monit Assess ; 192(2): 89, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31902034

RESUMO

Soybeans, as legumes, belong among food items that contribute most to the dietary intake of the heavy metal cadmium (Cd). The consumption of soy-based foods may contribute significantly to Cd intake in vegetarians as probably the most frequent consumers of these foods. In this research, the weekly dietary intake of Cd from soy-based foods was investigated in 119 participants (including vegetarians, vegans, and non-vegetarians) in the Czech Republic by means of a semi-quantitative food frequency questionnaire (SFFQ) with personal assistance and the measurement of body weight. Cd content in soy-based foods available on the market was determined by means of atomic absorption spectrometry after microwave digestion. Tofu, as the most frequently consumed food item in the vegetarian/vegan group, contributed most to the total dietary Cd intake. It contained 7.6 ± 0.1 µg Cd/kg, while the highest Cd content was observed in tempeh (18.1 ± 0.4 µg/kg). The highest mean dietary Cd intake per week from soy-based foods was 0.4 µg/kg b.w. and was found in the vegan group. The consumption of soy-based foods was the lowest in the non-vegetarian group as was the dietary intake of Cd, which was 0.04 µg/kg b.w. per week.


Assuntos
Cádmio/análise , Exposição Dietética/estatística & dados numéricos , Contaminação de Alimentos/estatística & dados numéricos , Poluentes do Solo/análise , Alimentos de Soja/análise , Soja/química , Peso Corporal , República Tcheca , Dieta , Monitoramento Ambiental , Fabaceae , Feminino , Humanos , Masculino , Espectrofotometria Atômica , Verduras , Vegetarianos
17.
J Environ Manage ; 261: 110113, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31999610

RESUMO

Soaring demand for technology metals (e.g., Cd, Ni) and its ever-depleting primary resources ask for alternative recovery from secondary sources. Ni-Cd battery is one such source that can abridge the gap between demand and supply of such metals. Biogenic recovery, being environmentally benign, is explored for Cd and Ni recovery to manage the menace of spent Ni-Cd battery. Studies with 20, 40 and 60 mg/L Cd2+ initial concentrations in batch mode (in triplicates) at pH 7.0 ± 0.2, 30 ± 0.5 °C and 120 rpm were conducted using sulfate-reducing bacteria for 10 days. Analysis of extracellular polymeric substance revealed that protein secretion was enhanced, thereby forming Cd-EPS binding. Biosolids were collected and freeze-dried for morphological analysis viz. FESEM/EDX, PXRD and TEM, which revealed the formation of CdS nanoparticles (JCPDS card #00-042-1411) in range of 2-6 nm. Similarly, combined effect with 5, 10 and 20 mg/L Ni2+ at 20 mg/L Cd2+ were also investigated. Furthermore, to test the efficacy for real field application, spent Ni-Cd battery was dismantled and its powder was characterized, digested with concentrated HCl at 70 °C and was fed in batch mode after cooling, wherein nanoparticles of Ni and Cd sulfides were formed that has potential as semi-conducting material.


Assuntos
Cádmio , Nanopartículas , Matriz Extracelular de Substâncias Poliméricas , Metais , Níquel , Sulfetos
18.
Environ Monit Assess ; 192(2): 108, 2020 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-31927632

RESUMO

The release of potentially toxic metal(loid)s (PTMs) such as As, Cd, Cr, Pb and Hg has become a serious threat to the environment. The anthropogenic contribution of these PTMs, especially Hg, is increasing continuously, and coal combustion in thermal power plants (TPPs) is considered to be the highest contributor of PTMs. Once entered into the environment, PTMs get deposited on the soil, which is the most important sink of these PTMs. This review centred on the sources of PTMs from coal and flyash and their enrichment in soil, chemical behaviour in soil and plant, bioaccumulation in trees and vegetables, health risk and remediation. Several remediation techniques (physical and chemical) have been used to minimise the PTMs level in soil and water, but the phytoremediation technique is the most commonly used technique for the effective removal of PTMs from contaminated soil and water. Several plant species like Brassica juncea, Pteris vittata and Helianthus annuus are proved to be the most potential candidate for the PTMs removal. Among all the PTMs, the occurrence of Hg in coal is a global concern due to the significant release of Hg into the atmosphere from coal-fired thermal power plants. Therefore, the Hg removal from pre-combustion (coal washing and demercuration techniques) coal is very essential to reduce the possibility of Hg release to the atmosphere.


Assuntos
Metais Pesados , Medição de Risco , Poluentes do Solo , Bioacumulação , Cádmio , Monitoramento Ambiental , Nível de Saúde , Humanos , Chumbo , Mercúrio/farmacocinética , Mercúrio/toxicidade , Metais Pesados/farmacocinética , Metais Pesados/toxicidade
19.
Sci Total Environ ; 713: 136665, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-31955111

RESUMO

Arsenic (As) and cadmium (Cd) typically exhibit divergent fates in soil, which complicates efforts to decrease As and Cd accumulation in the edible parts of crops. Here, we performed pot experiments to examine the effect of sulfate application on As and Cd accumulation in the grain of wheat grown in contaminated soil. Compared to the control (no sodium sulfate addition), application of 120 mg kg-1 sodium sulfate decreased the rhizosphere soil pH from 7.27 to 7.10 and increased the soil extractable Cd concentration; however, it did not significantly influence the soil extractable As concentration. However, sodium sulfate addition decreased As and Cd concentrations in wheat grain, in association with decreased As and Cd translocation from root and straw to grain, rather than from soil to root. Furthermore, sodium sulfate addition significantly decreased membrane lipid peroxidation and enhanced photosynthesis, while increasing the uptake of nitrogen, phosphorus, and sulfur. These effects increased the growth and grain weight of plants grown in As and Cd co-contaminated soil. Our findings provide insight into the mechanisms by which sulfate modulates As and Cd uptake and translocation in wheat; moreover, our findings will enable formulation of strategies to decrease As and Cd concentrations in the grain of wheat grown in As and Cd co-contaminated soil.


Assuntos
Triticum , Arsênico , Cádmio , Grão Comestível , Solo , Poluentes do Solo , Sulfatos
20.
J Agric Food Chem ; 68(7): 1974-1985, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31971785

RESUMO

Our aim was to investigate DNA mismatch repair (MMR) genes regulating cadmium tolerance in two soybean cultivars. Cultivars Liaodou 10 (LD10, Cd-sensitive) and Shennong 20 (SN20, Cd-tolerant) seedlings were grown hydroponically on Murashige and Skoog (MS) media containing 0-2.5 mg·L-1 Cd for 4 days. Cd stress induced less random amplified polymorphism DNA (RAPD) polymorphism in LD10 than in SN20 roots, causing G1/S arrest in LD10 and G2/M arrest in SN20 roots. Virus-induced gene silencing (VIGS) of MLH1 in LD10-TRV-MLH1 plantlets showed markedly diminished G1/S arrest but enhanced root length/area under Cd stress. However, an increase in G1/S arrest and reduction of G2/M arrest occurred in SN20-TRV-MSH2 and SN20-TRV-MSH6 plantlets with decreased root length/area under Cd stress. Taken together, we conclude that the low expression of MSH2 and MSH6, involved in the G2/M arrest, results in Cd-induced DNA damage recognition bypassing the MMR system to activate G1/S arrest with the assistance of MLH1. This then leads to repressed root growth in LD10, explaining the intervarietal difference in Cd tolerance in soybean.


Assuntos
Cádmio/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas de Plantas/metabolismo , Soja/genética , Soja/metabolismo , Cádmio/toxicidade , Dano ao DNA/efeitos dos fármacos , Reparo de Erro de Pareamento de DNA/efeitos dos fármacos , Proteínas de Ligação a DNA/genética , Pontos de Checagem da Fase G2 do Ciclo Celular , Proteínas de Plantas/genética , Soja/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA