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1.
Water Sci Technol ; 80(3): 448-457, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31596256

RESUMO

In the present study, continuous-flow column experiments (using glass column, Tygon tubing, and peristaltic pump Manostat Carter) were conducted to investigate the performance of permeable sorption barriers for the removal of cadmium and zinc from synthetic groundwater. Zeolite, ion-exchange resin and granular activated carbon as reactive materials were used. The effectiveness and stability of reactive materials were studied by monitoring of changes of metal ions concentration and selected background anions and cations concentration in groundwater during its flow through columns. Results showed that ion exchange resin was the most effective material of permeable reactive barrier (PRB). Performance of resin barrier remained effective (>99.5% metal ions removal) for the time corresponding to on average of about 10,000 min. The high efficiency of ion-exchange resin in PRB for removal of heavy metals from groundwater was coupled with its reactivity and long barrier lifetime. The breakthroughs in the column tests on activated carbon and zeolite using synthetic groundwater occurred much earlier as compared to resin. Therefore, the system using resin requires smaller amount to treat a given volume of groundwater as compared to other materials. Moreover, the presence of other ions did not impact on activity and permeability of barrier filled with resin.


Assuntos
Cádmio/análise , Água Subterrânea/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Zinco/análise , Íons
2.
Chem Commun (Camb) ; 55(79): 11932-11935, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31531427

RESUMO

An enzyme-free DNA circuit was designed for the amplified detection of Cd2+ based on hairpin probe-mediated toehold binding and branch migration. A Cd2+-specific aptamer was used to recognize Cd2+ and a G-quadruplex was used to report the detection signal. The assay is sensitive, with a detection limit of 5 pM.


Assuntos
Aptâmeros de Nucleotídeos/química , Cádmio/análise , DNA/química , Técnicas Biossensoriais/métodos , Corantes Fluorescentes/química , Quadruplex G , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico , Sensibilidade e Especificidade , Espectrometria de Fluorescência
3.
Environ Monit Assess ; 191(10): 602, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31478102

RESUMO

Globally, millions of tons of coal fly ash (CFA) are generated per year, and the majority of this material is usually stored in stock piles or landfills, and in a long-term, it can be an environmental hazard if rainwater infiltrates the ashes. Long-term leaching studies of Brazilian ashes are scarce. The purpose of this study was to evaluate arsenic, cadmium, molybdenum, lead, and zinc leaching behavior from a Brazilian CFA by a column experiment designed to simulate field conditions: slightly acid rain considering seasonality of precipitation and temperature for a long-term leaching period (336 days). All elements were leached from CFA, except lead. Elements leaching behavior was influenced by leaching time, leaching volume, and temperature. Higher leachability of As and Cd from CFA during warm and wet season was observed. Results indicate a potential risk to soil and groundwater, since ashes are usually stored in uncovered fields on power plants vicinity.


Assuntos
Cinza de Carvão/química , Monitoramento Ambiental , Metais Pesados/análise , Arsênico/análise , Arsênico/química , Brasil , Cádmio/análise , Cádmio/química , Água Subterrânea , Chumbo/análise , Chumbo/química , Molibdênio/análise , Molibdênio/química , Centrais Elétricas , Solo/química , Instalações de Eliminação de Resíduos , Zinco/análise , Zinco/química
4.
Sci Total Environ ; 692: 1022-1028, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31539934

RESUMO

Contamination of agricultural soil with cadmium (Cd) poses a severe threat to food safety and human health, especially for Cd in rice. It is very important to identify Cd bioaccumulation in rice in order to screen Cd-safe cultivars. In the present study, 183 pairs of rice and soil data collected from Cd-contaminated soil were used to investigate the differences of Cd bioaccumulation in grains among rice cultivars. The results showed that the adverse effect on grain Cd accumulation of japonica was less than that of indica under Cd exposure. The percentage of japonica with grain Cd concentration exceeding 0.2 mg/kg reduced 50.3% compared with indica. Partial correlation analyses suggested that lower pH contributed to Cd accumulation in grains, and a significant increase in grain Cd concentration was observed with increasing soil Cd concentration. The bioaccumulation factors (BCF) of Cd in rice grains could be divided into 5 grades by combining an empirical soil-plant transfer model with species sensitivity distribution (SSD). Grades with lower Cd bioaccumulation (grades 1 and 2) were dominated by japonica, and the intrinsic sensitivity index of Cd-enrichment (k value) and straw to grain transfer factors (TF) increased with ascending grades. Average k value and TF of cultivars in grade 5 were 1.4-7.9 and 1.5-5.7 times higher than those of cultivars in grades 1 to 4, which eventually caused the increase of Cd accumulation in grains. The lower level of Cd absorption and translocation contributed to reducing the bioaccumulation of Cd in rice grains had been proved by the classification of rice on Cd accumulation. Considering the influence of soil properties and intrinsic sensitivity of rice, cultivars with grain Cd bioaccumulation controlled at low levels to safe for human consumption could be identified on Cd-contaminated soils.


Assuntos
Agricultura , Cádmio/análise , Oryza/química , Poluentes do Solo/análise , Monitoramento Ambiental
5.
Sci Total Environ ; 687: 768-779, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31412480

RESUMO

Metals are persistent pollutants, able to accumulate in the biota and magnify in trophic web. In the specific case of cadmium contamination, it has been the subject of considerable interest in recent years because of its biological effects and it is one of major pollutant in estuarine areas. Ucides cordatus is considered a mangrove local sentinel crab species in Brazil and there are previous studies reporting crab subpopulations living from pristine to heavily metal impacted areas in São Paulo coast (Southeastern Brazil). Taking into account the background knowledge about these subpopulations, we proposed the hypothesis that crabs from a highly polluted mangrove (Cubatão - CUB) have developed biological tolerance to cadmium compared to animals from an Environmental Protected Area (Jureia - JUR). Aiming to verify this hypothesis, we have investigated total bioaccumulation and subcellular partition of Cd, besides biomarkers' responses during a long-term exposure bioassay (28 days, with weekly sampling) using a supposedly safe Cd concentration (0.0022 mg L-1). Specimens from the pristine area (JUR) accumulated higher total Cd, as such as in its biologically active form in gills. Animals living in the polluted site (CUB) presented higher amounts of Cd in the mainly detoxifying tissue (hepatopancreas), which could be considered a pathway leading to tolerance for this metal. Multivariate analysis indicated that bioaccumulation (active, detoxified and total Cd) is linked to geno-cytotoxic damages. CUB subpopulation was considered more tolerant since it presented proportionally less damage and more capacity to allocate Cd in the main detoxifying forms and tissues.


Assuntos
Braquiúros/fisiologia , Cádmio/toxicidade , Monitoramento Ambiental , Espécies Sentinelas/fisiologia , Poluentes Químicos da Água/toxicidade , Áreas Alagadas , Animais , Brasil , Cádmio/análise , Hepatopâncreas , Poluentes Químicos da Água/análise
6.
Environ Monit Assess ; 191(9): 538, 2019 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-31377862

RESUMO

In this study, metal accumulation in green sea urchins (Strongylocentrotus droebachiensis) was investigated near the former Black Angel lead-zinc mine in Maarmorilik, West Greenland. Sea urchins (n = 9-11; 31-59 mm in diameter) were collected from three stations located at < 1 km, 5 km, and 12 km (reference site) away from the former mine site, respectively. After collection, tissue of the sea urchins was divided into gonads and remaining soft parts (viscera) before subjected to chemical analyses. Focus was on eight elements found in elevated concentrations in the mine waste (iron, copper, zinc, arsenic, silver, cadmium, mercury and lead). Sea urchins at the mine site contained significantly more copper, mercury and lead compared with the reference site for both the gonads and viscera, while the latter also contained significantly more iron, zinc and silver. Arsenic and cadmium were not significantly elevated in sea urchins at the mine site. Most elements were found in higher concentrations in the viscera compared with the gonads. For comprehensive monitoring of metal pollution at mine sites, a diverse selection of monitoring organisms is necessary. The study shows that green sea urchins accumulate selected metals and can be used as a monitoring organism for mining pollution, at least for iron, copper, zinc, silver, mercury and lead. However, the results also show that green sea urchins are less likely to reflect small environmental changes in loading of most metals (except iron, copper and silver) and for arsenic compared to suspension feeders such as blue mussels.


Assuntos
Monitoramento Ambiental , Poluição Ambiental , Chumbo/análise , Mytilus edulis/química , Strongylocentrotus/química , Zinco/análise , Animais , Cádmio/análise , Groenlândia , Mineração
7.
J Agric Food Chem ; 67(35): 9877-9884, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31398030

RESUMO

Heavy metal contaminants and nutrient deficiencies in soil negatively affect crop growth and human health. The plant cadmium resistance (PCR) protein transports heavy metals. The abundance of PCR is correlated with that of cell number regulator (CNR) protein, and the two proteins have similar conserved domains. Hence, CNR might also participate in heavy metal transport. We isolated and analyzed TaCNR5 from wheat (Triticum aestivum). The expression level of TaCNR5 in the shoots of wheat increased under cadmium (Cd), zinc (Zn), or manganese (Mn) treatments. Transgenic plants expressing TaCNR5 showed enhanced tolerance to Zn and Mn. Overexpression of TaCNR5 in Arabidopsis increased Cd, Zn, and Mn translocation from roots to shoots. The concentrations of Zn and Mn in rice grains were increased in transgenic plants expressing TaCNR5. These roles of TaCNR5 in the translocation and distribution of heavy metals mean that it has potential as a genetic biofortification tool to fortify cereal grains with micronutrients.


Assuntos
Manganês/metabolismo , Oryza/genética , Oryza/metabolismo , Proteínas de Plantas/genética , Triticum/genética , Zinco/metabolismo , Arabidopsis/química , Arabidopsis/genética , Arabidopsis/metabolismo , Biofortificação , Transporte Biológico , Cádmio/análise , Cádmio/metabolismo , Manganês/análise , Oryza/química , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/química , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Triticum/química , Triticum/metabolismo , Zinco/análise
8.
Environ Pollut ; 253: 959-965, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31351304

RESUMO

Application of Zinc (Zn) is considered an effective measure to reduce Cadmium (Cd) uptake and toxicity in Cd-contaminated soils for many plant species. However, interaction between Zn and Cd in rice plant is complex and uncertain. In this study, four indica rice cultivars were selected to evaluate the effect of Zn exposure in an EGTA-buffered nutrient solution under varying Zn activities and a field level of Cd activity to characterize the interaction between Zn and Cd in rice. Severe depression in shoots' biomass, tiller number, and SPAD (Soil and Plant Analyzer Development) value were found at both Zn deficiency and Zn phytotoxicity levels among four tested rice cultivars. There existed a strong antagonism interaction between Zn and Cd in both shoot and root from Zn deficiency to Zn phytotoxicity. The reduction of Cd accumulation in roots and shoots could be explained by the competition between Zn and Cd as well as the dilution effect of increasing biomass. The conflicting effect of Zn supply on Cd uptake may be attributed to the increasing transfer ratio of Cd from root to shoot with the increasing Zn2+ activities and the strong depression of Fe and Mn in shoots with the increasing Zn2+ activities as well as the variation of genotypes. Balance between Zn and Cd should be considered in field application.


Assuntos
Cádmio/metabolismo , Oryza/fisiologia , Poluentes do Solo/metabolismo , Zinco/metabolismo , Transporte Biológico/efeitos dos fármacos , Biomassa , Cádmio/análise , Poluição Ambiental , Oryza/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
9.
Environ Pollut ; 253: 966-973, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31351305

RESUMO

In present study, the analyses of essential [copper (Cu), cobalt (Co), selenium (Se) and zinc (Zn)] and non-essential elements [mercury (Hg), lead (Pb), cadmium (Cd) and arsenic (As)] in 7 fish species consumed by the indigenous people of the European Russia Arctic were conducted. The Nenets Autonomous Region, which is located in the north-eastern part of European Russia, was chosen as a Region of interest. Within it, the Nenets indigenous group (n = 6000) constitutes approximately 10% of the total population. Nearly all of the Nenets live a traditional life with fish caught in the local waters as a subsistence resource. We found that northern pike contained twice the amount of Hg compared with roach, and 3-4 times more than other fish species commonly consumed in the Russian Arctic (namely, Arctic char, pink salmon, navaga, humpback whitefish and inconnu). Fish Hg concentrations were relatively low, but comparable to those reported in other investigations that illustrate a decreasing south-to-north trend in fish Hg concentrations. In the current study, northern pike is the only species for which Hg bioaccumulated significantly. In all fish species, both Cd and Pb were present in considerably lower concentrations than Hg. The total As concentrations observed are similar to those previously published, and it is assumed to be present primarily in non-toxic organic forms. All fish tissues were rich in the essential elements Se, Cu and Zn and, dependent on the amount fish consumed, may contribute significantly to the nutritional intake by indigenous Arctic peoples. We observed large significant differences in the molar Se/Hg ratios, which ranged from 2.3 for northern pike to 71.1 for pink salmon. Values of the latter <1 may increase the toxic potential of Hg, while those >1 appear to enhance the protection against Hg toxicity.


Assuntos
Exposição Dietética/estatística & dados numéricos , Peixes/metabolismo , Alimentos Marinhos/estatística & dados numéricos , Oligoelementos/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Regiões Árticas , Arsênico/análise , Cádmio/análise , Cobalto/análise , Cobre/análise , Cyprinidae , Humanos , Mercúrio/análise , Federação Russa , Alimentos Marinhos/análise , Selênio/análise , Oligoelementos/análise , Poluentes Químicos da Água/análise , Zinco/análise
10.
Food Chem ; 299: 125126, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31284243

RESUMO

The health risk assessment of exposure to toxic metals through the consumption food crops is very important. The present study was aimed to investigate the bioaccessibility of toxic metals (including arsenic, lead and cadmium) in rice through an in vitro gastrointestinal digestion model, and assess health risks associated with these metals in raw, cooked and digested rice. Total and bioaccessible concentration of metals were measured by introducing the prepared samples into the inductively coupled plasma-optical emission spectroscopy. Based on the results, the bioaccessible toxic metals in gastric phase were significantly higher than that in both oral and small intestinal phases. The estimated concentrations of these metals in the raw and cooked rice are very far from the actual exposure state. Therefore, to assess the extent of health risks associated with the subjected toxic metals through the rice consumption, the actual exposure value of the metals (bioaccessible value) should be considered.


Assuntos
Arsênico/farmacocinética , Cádmio/farmacocinética , Contaminação de Alimentos/análise , Chumbo/farmacologia , Metais/farmacocinética , Oryza/química , Arsênico/análise , Disponibilidade Biológica , Cádmio/análise , Culinária , Digestão , Humanos , Irã (Geográfico) , Chumbo/toxicidade , Metais/toxicidade , Medição de Risco
11.
Zhongguo Zhong Yao Za Zhi ; 44(9): 1793-1798, 2019 May.
Artigo em Chinês | MEDLINE | ID: mdl-31342704

RESUMO

Aiming at the phenomenon of heavy metal Cd exceeding the standard of Chuanxiong medicinal materials,the accumulation of 12 inorganic elements,including heavy metals,in Ligusticum chuanxiong was studied in this paper. It was found that the contents and distribution of most inorganic elements in the stems and leaves of L. chuanxiong were higher than those in the rhizomes at seedling and shooting stages. The content of most elements in rhizome reached the highest at harvest stage,and the distribution ratio of some elements in rhizome was higher than that in stem and leaf at harvest stage. But rhizome,stem and leaf of L. chuanxiong have relatively stable absorption capacity and enrichment effect on different elements,and are less affected by growth period and position. Rhizomes and stems and leaves of L. chuanxiong were enriched with Cd,and stems and leaves also accumulated Pb at seedling stage and stem stage. The absorption capacity of Pb in stems and leaves of L. chuanxiong was higher than that of rhizomes,and the ability of absorbing Cd was less than that of rhizomes at harvest time. The total uptake of Cd and Pb by L. chuanxiong decreased with the prolongation of growth time,but the proportion of Cd and Pb in rhizome increased,so that the content of Cd and Pb increased with the prolongation of growth time.


Assuntos
Cádmio/análise , Ligusticum/química , Metais Pesados/análise , Medicamentos de Ervas Chinesas/química , Folhas de Planta/química , Caules de Planta/química , Rizoma/química
12.
Ecotoxicol Environ Saf ; 182: 109444, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31310903

RESUMO

Solanum nigrum L. has a high potential for the remediation of Cd-contaminated soil, and nitrogen fertilizer supply is an effective method to further improve its phytoremediation potential. The soil pot culture experiment was used to explore 4 kinds of nitrogen fertilizers the best fertilizer addition concentrations and their strengthening mechanisms. The results showed that S. nigrum biomass increased with increasing N doses until 800 mg kg-1, where the biomass reached maximum and no longer improved (p < 0.05). However, Cd concentration accumulated by S. nigrum and the extractable Cd concentration in soil did not show a significant decrease (p < 0.05). In this experiment, when N fertilizer was added at 800 mg kg-1 (NH4HCO3, NH4Cl, (NH4)2SO4 and CH4N2O fertilizers), the biomass of the aboveground S. nigrum parts improved to the maximum under (NH4)2SO4 and CH4N2O treatments, i.e. 5.86 g pot-1 and 5.83 g pot-1, increased by 5.92- and 5.89-fold, respectively (p < 0.05), compared to the controls without N fertilizers addition. At the same time, Cd phytoaccumulation in plants was elevated to 128.40 µg pot-1 and 129.14 µg pot-1, increased by 6.20- and 6.24-fold, respectively (p < 0.05), compared to control with no fertilizer added. The results of this experiment demonstrated that Cd phytoextraction capacity (µg pot-1) was the strongest under (NH4)2SO4 and CH4N2O treatments at N content of 800 mg kg-1, when plant nutrient recovery reached the maximum, and these 2 types of nitrogen fertilizers could be utilized to remediate Cd-contaminated soil in field experiments or even in practice.


Assuntos
Cádmio/metabolismo , Fertilizantes/análise , Nitrogênio , Poluentes do Solo/metabolismo , Solanum nigrum/fisiologia , Biodegradação Ambiental , Biomassa , Cádmio/análise , Solo , Poluentes do Solo/análise
13.
Ecotoxicol Environ Saf ; 182: 109459, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31344591

RESUMO

The utilization of forages grown on metal-contaminated soil can increase the risk of heavy metals entering the food chain and affecting human health because of elevated toxic metal concentrations. Meanwhile, hydrogen sulfide (H2S) and nitric oxide (NO) as signaling molecules are known to promote plant growth in metal-contaminated soils. However, the regulatory mechanisms of such molecules in plant physiology and soil biochemistry have not been well-documented. Hence, we investigate the role of the exogenous application of H2S and NO on alfalfa growth in lead/cadmium (Pb/Cd)-contaminated soil. Our results indicate that the signaling molecules increase the alfalfa chlorophyll and biomass content and improve alfalfa growth. Further, H2S and NO reduce the translocation and bioconcentration factors of Pb and Cd, potentially reducing the risk of heavy metals entering the food chain. These signaling molecules reduce metal-induced oxidative damage to alfalfa by mitigating reactive oxygen species accumulation and increasing antioxidant enzyme activities. Their exogenous application increases soil enzymatic activities, particularly of catalase and polyphenol oxidase, without significantly changing the composition and structure of rhizosphere bacterial communities. Interestingly, H2S addition enriches the abundance of plant-growth-promoting rhizobacteria in soil, including Nocardioides, Rhizobium, and Glycomyces. H2S is more effective than NO in improving alfalfa growth and reducing heavy-metal contamination of the food chain. These results provide new insights into the exogenous application of signaling molecules in alleviating metal-induced phytotoxicity, including an efficient strategy for the safe use of forages.


Assuntos
Cádmio/análise , Sulfeto de Hidrogênio/farmacologia , Chumbo/análise , Medicago sativa/efeitos dos fármacos , Óxido Nítrico/farmacologia , Poluentes do Solo/análise , Irrigação Agrícola , Biomassa , Cádmio/toxicidade , Fumigação , Sulfeto de Hidrogênio/administração & dosagem , Chumbo/toxicidade , Medicago sativa/química , Medicago sativa/crescimento & desenvolvimento , Microbiota/efeitos dos fármacos , Óxido Nítrico/administração & dosagem , Poluentes do Solo/toxicidade
14.
Environ Pollut ; 252(Pt B): 1509-1518, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31272010

RESUMO

Extracellular polymeric substance (EPS)-mineral associations occur naturally in soil and sediments, and they might play crucial roles in heavy metals immobilization. In this study, EPS-montmorillonite composites with different weight ratios were characterized and investigated for their Cd(II) sorption behavior. The results showed that the EPS chains can intercalate into montmorillonite layers by hydrogen bonding connection and chemical reaction between CO, C-N and COO- groups with interlayer cations of montmorillonite, therefore promoting delamination of montmorillonite, especially under a lower weight ratio. An enhancement adsorption of heavy metals was obtained with the composites at lower weight ratios of 1:50 and 0.5:50, whereas composites with higher weight ratio of 5:50 presented a reduced adsorption ability, demonstrating that adsorption of Cd(II) onto the EPS-montmorillonite composites was weight ratio dependent. AFM, CLSM, FT-IR and XPS analysis illustrated that the enhancement of sorption under low weight ratio can be attributed to the release of surface active sites of EPS because of reduced aggregation, the increase of negative surface charges when EPS and montmorillonite were interacted and additional bridging of cadmium ions between EPS and montmorillonite. These findings extend the knowledge into the mobility and fate of Cd(II) in organic matter rich soils and sediments.


Assuntos
Bentonita/química , Cádmio/análise , Matriz Extracelular de Substâncias Poliméricas/química , Poluentes do Solo/análise , Adsorção , Ligações de Hidrogênio , Solo/química , Propriedades de Superfície
15.
Bull Environ Contam Toxicol ; 103(3): 416-420, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31342133

RESUMO

This study aimed at determining the competition of cadmium (Cd), lead (Pb), zinc (Zn) and copper (Cu) on their assimilation, on the food consumption and the growth of terrestrial isopod Porcellio laevis. Individuals were exposed to artificially contaminated litter of Quercus for 4 weeks and were weekly weighed. At the end of the experiment, the concentration of Cd, Pb, Zn and Cu in individuals were measured by atomic absorption spectrometry. Biological parameters such as growth, and bioaccumulation factor (BAF) were calculated and results from the various treatments were compared. Depending on metals, weight loss or gain were recorded for isopods during the four weeks of exposure. A weight loss was measured on individuals exposed to Cd-contaminated litter whereas a weight gain was highlighted for those exposed to the Zn-contaminated litter. BAF values revealed that P. laevis was macroconcentrator of Zn and Cu and deconcentrator of Cd and Pb.


Assuntos
Isópodes/fisiologia , Metais Pesados/toxicidade , Poluentes do Solo/toxicidade , Animais , Cádmio/análise , Cádmio/toxicidade , Cobre/toxicidade , Metais Pesados/análise , Zinco/análise , Zinco/toxicidade
16.
Environ Pollut ; 252(Pt B): 1406-1411, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31260940

RESUMO

Cadmium (Cd) contamination of the soil is one of the most serious environmental problems of agricultural production. Phytoremediation has attracted increasing attention because it can safely remove the soil contaminates via plant uptake, accumulations and plant harvesting. However, the high Cd toxicity to plant tissues and treatment of the large amount of hazardous plant residues from phytoremediation have limited its commercial implementation. Here we show that the leaves of the tall fescue (Festuca arundinacea) can excrete Cd out to avoid Cd toxicity in plant tissues. Cd specific fluorescence spectroscopy with laser confocal scanning microscope, screening electron microscope with energy dispersive spectroscopy and guttation fluids analysis confirmed that leaf hydathodes were the pathway of Cd excretion in tall fescue. Element analysis showed that Cd was preferentially excreted out when compared to the ion nutrients. The amount of leaf Cd excretion was linearly increased in response to the Cd stress period. The phytoremediation efficiency was evaluated to remove 14.4% of soil Cd annually by the leaf Cd excretion in our experimental system. These findings indicate that a novel strategy of Cd phytoexcretion based on washing-off and collection of leaf surface Cd is feasible to avoid Cd toxic in plant tissues and the high treatment cost of hazardous plant residues.


Assuntos
Biodegradação Ambiental , Cádmio/análise , Festuca/metabolismo , Poluentes do Solo/análise , Solo/química , Folhas de Planta/química
17.
Food Chem ; 300: 125202, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31330374

RESUMO

The aim of a three-year study was to assess the effect of combined biofortification with I and Se in carrot. Four cultivars ('Askona' F1, 'Samba' F1, 'Kazan' F1 and 'White Satin') were grown in soil fertilized with KI (4 kg I ha-1) and Na2SeO4 (0.25 kg Se ha-1). The I + Se fertilization did not affect yield but the plants of all cultivars accumulated both elements in leaves and roots. On average, the I and Se contents in roots increased 7.7-times for I and 4.9-times for Se as well as the average I:Se molar ratio was 0.28:1. The contents of both elements in roots remained well below the hazard threshold thus the intake of 100 g of biofortified carrot would substantially cover the RDA for I and Se. The changes in chemical composition of roots (nitrates, phenolic compounds, sugars, carotenoids, macro-, microelements and cadmium) were rather year-dependent than affected by the applied I + Se fertilization.


Assuntos
Biofortificação/métodos , Daucus carota/química , Iodo/farmacologia , Raízes de Plantas/química , Selênio/farmacologia , Cádmio/análise , Carotenoides/análise , Daucus carota/efeitos dos fármacos , Daucus carota/crescimento & desenvolvimento , Fertilizantes , Alimentos Fortificados/análise , Iodo/análise , Iodo/farmacocinética , Polônia , Selênio/análise , Selênio/farmacocinética , Solo/química
18.
Food Chem ; 298: 125084, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260980

RESUMO

A method for simultaneous determination of cadmium and iron in cereal flakes using high-resolution continuum source graphite furnace atomic absorption spectrometry is presented. Sample digest is introduced into the graphite furnace together with Pd/Mg(NO3)2 modifier. The primary absorption line of cadmium and adjacent secondary line of iron are used for the determination. Atomization is performed as a two-step process in order to meet ideal conditions for both elements. Interference produced by molecular absorption of PO molecular bands is suppressed by correction model using least squares background correction. Using the proposed method, levels of cadmium and iron were determined in different kinds of cereal flakes, where both elements are of great interest. Working range (0.01-2 µg L-1 for Cd and 10-500 µg L-1 for Fe) was suitable for the determination of analytes in samples. The method is fast, robust, and may be routinely used routinely in the analysis of foodstuffs.


Assuntos
Cádmio/análise , Grão Comestível/química , Análise de Alimentos/métodos , Ferro/análise , Espectrofotometria Atômica/métodos , Grafite/química
19.
Ecotoxicol Environ Saf ; 182: 109394, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31276885

RESUMO

Potentially toxic metal (PTM) contamination coupled with soil acidification has posed a severe threat to agricultural sustainability of tropical region in the world. In this study, a vermicopomst (VC) produced from vermicomposting cattle manure under tropical environment was applied to remediating a tropical acidic soil in Hainan, China. The effectiveness of VC in reducing available PTMs in soils was evaluated by incubation experiments with a Cd, Cr or Ni spiked soil and a Cd contaminated field soil. The dynamic changes of soil physical, chemical and biological properties after VC amendment were determined to understand the mechanisms of PTM immobilization. The results showed that VC amendment significantly reduced 0.01M CaCl2 extractable amounts of Cd, Ni and Cr in the spiked soils, and CaCl2 extractable Cd was reduced by 49.3% when VC was amended to the Cd contaminated field soil. Thermodynamic studies showed that VC had a high adsorption capacity for Cd, Ni and Cr, with the maximum adsorption (obtained from the Langmuir model) of 33.45, 26.17, and 20.88 mg/g, respectively. The reduction in CaCl2 extractable metals after VC amendment was consistent with the order of maximum adsorption of VC for Cd, Ni, and Cr. Vermicompost amendment increased soil pH by 0.7 to 1.5 units, which is positively related with VC rate, but negatively with the decrease in extractable metals. These results indicates that adsorption of metals onto VC and an increase in soil pH after VC amendment are likely responsible for the decreased availability of Cd, Ni, and Cr in the contaminated soil. In addition, the addition of stable organic substances and subsequent formation of water-stable aggregates may be also beneficial for immobilizing PTMs and improving tropical soil quality.


Assuntos
Compostagem/métodos , Metais Pesados/análise , Poluentes do Solo/análise , Adsorção , Agricultura , Animais , Cádmio/análise , Bovinos , China , Poluição Ambiental , Esterco , Fenilpropionatos , Solo/química
20.
Sci Total Environ ; 688: 600-608, 2019 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-31254826

RESUMO

Cadmium production has risen 1000-fold in the past 100 years, from under 20 to over 20,000 tons per year, causing anthropogenically-mobilized Cd to overwhelm natural sources in global cycling. Cadmium has no known biological function in humans, yet has biochemical behaviors similar to zinc and manganese, making exposure detrimental to human health. Identifying and quantifying the sources of Cd for human sub-populations is key to reducing exposures. Cadmium stable isotopes may provide a method for tracing Cd sources throughout the environment and the human body, but at present the limited database for high precision Cd isotopic compositions is inadequate to support such an analysis. Here, we provide new Cd isotope data on dietary sources, cigarette smoking components, and environmentally relevant standard reference materials. Results indicated that minor but significant variations are observed in food products (e.g., peanuts, sunflower seeds, spinach, kale, lettuce, cocoa powder; ~0.9‰ at 4 amu) that may be useful for tracing contamination in agricultural soils. In contrast, Cd isotope fractionation during smoking is larger (~6‰ at 4 amu) and has implications for tracing cadmium sources from tobacco combustion in the environment and throughout the human body. The primary inhaled component of cigarette smoke contains highest delta values (δ116/112Cd or δ114/110Cd ~5.2‰), while the second-hand smoke and cigarette ash have the lowest delta values (δ116/112Cd or δ114/110Cd ~-0.9‰). Used cigarette butts have δ114/110Cd ~2.4‰, in between the values measured in ash/s hand smoke and the inhaled smoke components. The high delta values of the inhaled smoke indicate that Cd isotopes may be used to determine the extent of Cd exposure due to smoking in human biological samples. This study provides new data for previously uncharacterized isotopic reservoirs that can be included in future studies of Cd source-exposure tracing.


Assuntos
Cádmio/análise , Poluentes do Solo/análise , Tabaco/química , Fracionamento Químico , Monitoramento Ambiental , Isótopos/análise , Solo/química , Poluição por Fumaça de Tabaco/análise
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