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1.
Environ Monit Assess ; 192(2): 138, 2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-31980942

RESUMO

The present study was conducted to investigate the concentrations of potential toxic metals (PTMs) in agricultural soil (n = 25) and their bioaccumulation in wheat crop (n = 25) collected from alongside the Kurram River, Pakistan. The highest concentrations of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn in soil samples were 0.16, 19.5, 14.7, 46.5, 13.5, 14.5, 14.0, and 19.7 mg kg-1, respectively. In the edible tissues of cultivated wheat crop, the highest concentrations of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were 0.15, 10.00, 8.75, 22.25, 11.00, 11.25, 10.50, and 7.50 mg kg-1, respectively. The selected PTM concentrations in soil samples were observed within their respective permissible limits set by the Food and Agriculture Organization (FAO) and State Environmental Protection Administration (SEPA) China, while in wheat crops, the Cr and Pb concentrations were above the permissible limits of both FAO and SEPA China. The results showed that the orders of PTMs were Fe > Zn > Cr > Cu > Ni > Pb > Mn in soil and Fe > Ni > Mn > Pb > Cr > Cu > Zn in wheat. The highest PTM concentrations were reported in the sample collected near dumping sites. The results of different soil pollution indices including geo-accumulation index (Igeo), contamination factor (CF), and enrichment factor (EF) indicated that the soil of the study area was moderately to severely contaminated. The ADI values of wheat crops were less than 1, while the HQ varied among different PTMs with the highest value of 2.118 for Pb, and the lowest for Zn (0.007). The results indicated that anthropogenic intervention has made a substantial contribution to soil contamination with PTMs and subsequent uptake by wheat, which may exert potential human health risk.


Assuntos
Metais Pesados , Poluentes do Solo , Triticum , Bioacumulação , China , Monitoramento Ambiental , Humanos , Paquistão , Medição de Risco , Solo , Poluentes do Solo/farmacocinética , Triticum/química
2.
Chemosphere ; 241: 125106, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31683428

RESUMO

A pot experiment was conducted to investigate the possible mediatory effect of organic amendments (vermicompost and biochar) and selenium (Se) on Cd bioaccumulation in both rice cultivars (high-Cd accumulation rice: Yuzhenxiang (YZX) and low-Cd accumulation rice: Changliangyou772 (CLY)) in high-Cd-contaminated soils. The results showed that Cd sensitivity and tolerance were cultivar-dependent, and grain Cd contents for CLY accorded with the Chinese national food safety standards (0.2 mg kg-1), whereas grain Cd levels for YZX were 1.4-5.8 times higher than those for CLY. Soil applications of amendments decreased grain Cd levels by 3.5%-36.9% for YZX and 36.1%-74.4% for CLY. Moreover, vermicompost (VC) was more effective in reducing Cd bioaccumulation than biochar (BC). A combination of Se and organic amendments could significantly increase grain Se contents and help further reduce grain Cd levels by 5.8%-20.8%, compared to the single organic amendments. This mitigation progress could be attributed to the changes of Cd translocation and distribution among rice tissues and the inhibition of Cd bioavailability in soil through the alteration in soil properties. Organic amendments, especially high dose (5%), increased soil pH and organic matter contents, and correspondingly decreased soil Cd bioavailability. A sequential extraction analysis suggested that organic amendments and Se facilitated the transformation of soil Cd from the bioavailable form to the immobilized Cd form, and thus decreased grain Cd levels. Hence, co-applications of organic amendments and Se in combination with low-Cd accumulation cultivar could be an effective strategy for both Se needs of humans and safe utilization of Cd polluted soil.


Assuntos
Cádmio/farmacocinética , Carvão Vegetal/farmacologia , Compostagem , Oryza/metabolismo , Selênio/farmacologia , Disponibilidade Biológica , Cádmio/análise , Grão Comestível/química , Exposição Ambiental/normas , Humanos , Oryza/química , Selênio/análise , Solo/química , Poluentes do Solo/análise , Poluentes do Solo/farmacocinética , Especificidade da Espécie
3.
Chemosphere ; 241: 125095, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31683432

RESUMO

Cultivating cadmium (Cd)-safe rice lines, which show low Cd accumulation in brown rice, is generally beneficial to ensure food safety. The Cd retention in root of Cd-safe rice line D62B plays an important role in its low Cd translocation from root to shoot. To understand the mechanism of Cd retention in root, a hydroponic experiment was conducted to investigate the subcellular distribution of Cd and the contribution of polysaccharides to Cd binding to the root cell wall of a Cd-safe rice line D62B with a common rice line Luhui17 as a control material. D62B retained more Cd in the root by sequestrated a higher proportion of Cd in the cell wall, further it transferred less Cd to shoot. Close to half of the Cd in the root cell wall of D62B was accumulated in the hemicellulose 1 (HC1), and the proportions of HC1 in it were 1.2-1.7 times higher than these of Luhui17. The proportion of Cd in the pectin showed a dose-dependent increase in two rice lines. D62B contained significantly higher uronic acid concentrations of the pectin and greater pectin methyl esterase (PME) activities than Luhui17 in the root cell wall. These results indicated that a superior Cd binding capacity of the cell wall polysaccharides in D62B played an important role in its Cd retention in root.


Assuntos
Cádmio/farmacocinética , Parede Celular/metabolismo , Oryza/efeitos dos fármacos , Raízes de Plantas/metabolismo , Cádmio/metabolismo , Parede Celular/química , Parede Celular/efeitos dos fármacos , Hidroponia , Oryza/citologia , Oryza/metabolismo , Pectinas/química , Pectinas/metabolismo , Células Vegetais/efeitos dos fármacos , Células Vegetais/metabolismo , Raízes de Plantas/citologia , Raízes de Plantas/efeitos dos fármacos , Polissacarídeos/química , Polissacarídeos/metabolismo , Poluentes do Solo/metabolismo , Poluentes do Solo/farmacocinética
4.
Chemosphere ; 241: 125059, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31606571

RESUMO

The climate-driven flooding poses a challenge for phytoremediation of contaminated soil, and the willow (Salix spp.) is a promising candidate coping with climate change and environmental pollution. In this study, uptake and accumulation of copper (Cu), zinc (Zn) and their bioavailability in the rhizosphere across the Salix clones under flooded versus non-flooded (control) conditions were investigated using a pot experiment. The tested Salix clones grew well without showing any toxic symptoms under non-flooded soil condition; in contrast, the clones showed 100% survival for long-term flooding with the development of hypertrophied lenticels and adventitious roots. There were wide clonal variations in biomass production and accumulation of Cu and Zn under flooded and non-flooded conditions. Flooded treatments dramatically decreased aboveground biomass across the Salix clones to different extents compared to the control. The non-flooded clones exhibited relatively high accumulation capacities of Cu and Zn in aerial parts. However, the flooded clones resulted in more substantial reductions in Cu and Zn accumulation in aerial parts, and most of Cu and Zn were limited in roots. EDTA-extractable Cu and Zn predicted well bioavailability of Cu and Zn to the Salix clones under the current condition. It was concluded that the Salix clones exhibited Cu and Zn phytoextraction traits (non-flooding) or phytostabilization traits (flooding), which provides a valuable insight into phytomanagement of contaminated soils by willows subjected to flooding stress.


Assuntos
Adaptação Fisiológica , Biodegradação Ambiental , Cobre/farmacocinética , Inundações , Salix/metabolismo , Zinco/farmacocinética , Biomassa , Cobre/análise , Raízes de Plantas/química , Salix/crescimento & desenvolvimento , Poluentes do Solo/análise , Poluentes do Solo/farmacocinética , Zinco/análise
5.
Chemosphere ; 241: 125006, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31590016

RESUMO

The use of ornamental plant will increase with the improvement in living standards in green and blue-green infrastructure of urban settings. Nicotiana alata is an ornamental plant, frequently grown as a model plant for horticulture, medicine, and scientific research studies throughout the world. Despite its popularity, little is known about the response of N. alata against heavy metals (HMs). This work is based on the hydroponic study to identify the impacts of selected HMs (Cd, Cr, Cu, Ni and Pb) on N. alata, at 0, 50 and 100 µM concentration, with the co-application of EDTA, at 0 and 2.5 mM in hydroponics system. The HMs uptake was found to be dose dependent, with significant higher uptake at 100 µM of respective HM. Highest cumulative uptake (mg kg-1 of HMs in root, shoot, and leaf dried weight) noted were 767.50 ±â€¯50.83, 862.30 ±â€¯23.83, 271.29 ±â€¯18.68, 1117.49 ±â€¯46.10 and 2166.81 ±â€¯102.09, for Cd, Cr, Cu, Ni, and Pb at 100 µM, respectively. It was identified that EDTA co-application with HMs resulted in boosted HMs uptake, with cumulative uptake percentage increment of 41.62, 54.67, 53.98, 34.48 and 19.92% for 100 µM of Cd, Cr, Cu, Ni, and Pb, respectively. Higher uptake led to negative impact on plant physiology, photosynthetic pigments, and higher lipid peroxidation, H2O2 contents, and electrolyte leakage that increased the stress. Higher HMs uptake induced higher antioxidant enzymatic response. It is recommended to incorporate appropriate soil modification to grow N. alata in sustainable infrastructures.


Assuntos
Ácido Edético/farmacologia , Metais Pesados/farmacocinética , Poluentes do Solo/farmacocinética , Tabaco/crescimento & desenvolvimento , Tabaco/metabolismo , Peróxido de Hidrogênio/análise , Metais Pesados/análise , Oxirredutases/análise , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Poluentes do Solo/análise
6.
Chemosphere ; 239: 124760, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31518923

RESUMO

Plant growth and yield are adversely affected by the uptake of toxic hexavalent chromium (Cr(VI)) from soil. The present study describes a facile technique to minimize the uptake of Cr(VI) by chickpea (Cicer arietinum) plant from soil using microporous activated carbon microfiber (ACF). Simultaneously, nano-sized carbon nanofibers (CNFs), grown over the ACF substrate, are used as an efficient carrier of the Cu micronutrient from soil to root, shoot and leaf of the plants. Adsorption, seed germination and plant growth experiments are performed in Cr-stressed medium. The ACF, used as the adsorbent for Cr(VI) in metal-stressed soil (100 mg Cr kg-1 of soil) shows the metal loading of ∼23 mg g-1. Cr(VI) up to 50 mg L-1 concentration causes no stress during germination of chickpea seeds in Murashige and Skoog (MS) medium. A dose of 500 mg-mixture (treatment) per kg-soil increases root and shoot lengths by 52 and 11%, respectively than the control, during plant growth in the metal-stressed soil, attributed to an effective translocation of Cu-CNF through plant cells. Whereas Cr uptake by plant decrease to ∼46%, Cu uptake increase up to ∼120% in comparison to control by the mixture treatment. Protein and chlorophyll contents also significantly increased (*p < 0.05) with the application of treatment. The data clearly show that the mixture of ACF and Cu-CNF can be successfully used for the simultaneous scavenging of Cr(VI) from soil by adsorption over ACF and increased uptake of Cu by plants using the CNFs as the micronutrient carrier.


Assuntos
Cromo/farmacocinética , Cicer/crescimento & desenvolvimento , Nanofibras/química , Poluentes do Solo/farmacocinética , Adsorção , Carvão Vegetal/química , Clorofila/metabolismo , Cromo/isolamento & purificação , Cicer/efeitos dos fármacos , Cicer/metabolismo , Cobre/farmacocinética , Recuperação e Remediação Ambiental/métodos , Germinação , Folhas de Planta , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Solo/química , Poluentes do Solo/isolamento & purificação
7.
Chemosphere ; 240: 124909, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31550590

RESUMO

Environmental pollution and human health issues due to unrestricted electronic waste (e-waste) recycling activities have been reported at a number of locations. Among different e-waste recycling techniques, open burning of e-waste releases diverse metal(loid)s into the environment, which has aroused concern worldwide. In human health risk assessments (HHRAs), oral ingestion of soil can be a major route of exposure to many immobile soil contaminants. In vitro assays are currently being developed and validated to avoid overestimation of pollutants absorbed by the human body when calculating total pollutant concentrations in HHRAs. In this study, Cu, As, Cd, Sb, and Pb bioaccessibility in polluted soils (n = 10) from e-waste open burning sites at Agbogbloshie in Accra, Ghana, was assessed using an in vitro assay, the physiologically based extraction test. A bioaccessibility-corrected HHRA was then conducted to estimate the potential health risks to local inhabitants. The in vitro results (%) varied greatly among the different metal(loid)s (Cu: 1.3-60, As: 1.3-40, Cd: 4.2-67, Sb: 0.7-85, Pb: 4.1-57), and also showed marked variance between the gastric phase and small intestinal phase. The particle sizes of soil samples and chemical forms of metal(loid)s also influenced bioaccessibility values. Using these bioaccessibility values, both the hazard index and carcinogenic risk were calculated. The hazard index was above the threshold value (>1) for 5/10 samples, indicating a potential health risk to local inhabitants.


Assuntos
Resíduo Eletrônico , Metaloides/análise , Medição de Risco , Poluentes do Solo/farmacocinética , Disponibilidade Biológica , Exposição Dietética/efeitos adversos , Exposição Dietética/análise , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Monitoramento Ambiental , Gana , Humanos , Concentração de Íons de Hidrogênio , Metaloides/farmacocinética , Metaloides/toxicidade , Metais/análise , Metais/farmacocinética , Metais/toxicidade , Tamanho da Partícula , Reciclagem , Solo/química , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
8.
Chemosphere ; 240: 124907, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31550592

RESUMO

Deciphering the mechanism of Cd accumulation in crops is imperative for minimizing soil-to-plant transfer of Cd to improve safe food production. Hydroponic experiments were performed examining Cd accumulation, growth performance and protein characteristics of two rice genotypes, Xiushui817 and Zheda821, with low and high grain Cd accumulation, respectively, under Cd stress and in the presence of Si. Xiushui817 had lower root-to-shoot Cd translocation and was more sensitive to Cd stress than Zheda821. Si reduced the shoot Cd content in both genotypes but more efficacy in Zheda821. Tandem mass tags (TMT)-based proteomic analysis identified 25 proteins associated with low grain Cd accumulation, including vacuolar H+-pyrophosphatase 1 (OVP1) that was up-regulated after Si addition in Zheda821. The sequence comparison of OVP1 showed one nucleotide difference in Xiushui817 relative to Zheda821 resulting in one amino acid. Overexpression of OVP1 reduced shoot Cd concentration and improved the growth of rice compared with WT under both control and Cd treatment. The results highlight the significant roles of OVP1 in both Cd accumulation and the Si-induced Cd reduction in rice. Our findings provide valuable insights into the molecular mechanism of low Cd accumulation and Si-induced decrease in Cd accumulation in rice. OVP1 could be used for transgenic overexpression in rice or other cereals for safe food production.


Assuntos
Cádmio/farmacocinética , Oryza/efeitos dos fármacos , Proteínas de Plantas/metabolismo , Pirofosfatases/metabolismo , Silício/farmacologia , Cádmio/toxicidade , Regulação da Expressão Gênica de Plantas , Genótipo , Hidroponia , Oryza/genética , Oryza/metabolismo , Proteínas de Plantas/genética , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/metabolismo , Plantas Geneticamente Modificadas , Proteômica/métodos , Pirofosfatases/genética , Poluentes do Solo/farmacocinética
9.
Chemosphere ; 240: 124916, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31563104

RESUMO

Cadmium contamination in greenhouse vegetable fields greatly limited the sustainable production especially of leafy vegetables. Hydroxyapatite (HAP), as a common soil amendment, has been widely used in the remediation of Cd-contaminated soils, while its remediation efficiency greatly depends on its particle sizes. In this study, a rhizobag pot experiment was conducted to investigate the effects of HAP (<60 nm, <12 µm and <80 µm) on bioavailability of Cd to celery grown in acidic and slightly Cd-contaminated greenhouse soil. The results suggested that HAP with the largest particle size (<80 µm) had the best effectiveness in reducing Cd uptake especially by the edible part of celery. Specifically, the increase in HAP (<80 µm) addition from 0.5% to 3% prominently reduced Cd concentrations in celery shoot by 19.6%-76.8% as compared with the untreated group. Also, adding HAP (<80 µm) especially at 3% significantly decreased translocation factor (TF) of Cd from celery root to shoot by 30.6% and reduced bioconcentration factor (BCF) of Cd from rhizosphere soil to celery shoot by 76.4%. These were predominantly associated with the significantly increased soil pH and the subsequently decreased soil CaCl2-Cd concentration after adding HAP (<80 µm). Overall, although rhizosphere soil pH was the key factor in controlling Cd uptake by edible celery and regulating BCF and TF of Cd, insignificant root-induced acidification had limited effect on the immobilization efficiency of Cd by HAP (<80 µm). In conclusion, HAP (<80 µm) has good potential for the remediation of Cd-contaminated greenhouse soils.


Assuntos
Apium/efeitos dos fármacos , Apium/metabolismo , Cádmio/farmacocinética , Durapatita/farmacologia , Poluentes do Solo/farmacocinética , Solo/química , Apium/crescimento & desenvolvimento , Biodegradação Ambiental , Disponibilidade Biológica , Cádmio/análise , Durapatita/química , Concentração de Íons de Hidrogênio , Tamanho da Partícula , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/metabolismo , Rizosfera , Poluentes do Solo/análise
10.
Chemosphere ; 240: 124913, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31563714

RESUMO

The combined toxicological effects of nickel (Ni) and butyl xanthate (BX), that is commonly used in flotation reagents for non-ferrous metals ore processing such as Ni, copper and lead ores, on soil microbial communities were studied by determining soil microbial activity, soil enzyme activities and Ni bioavailability. The results revealed that the exchangeable (EXC) and reducible (RED) fractions of Ni were higher in Ni/BX mixture than Ni alone, probably because BX reacts with Ni to form complexes that lead an increase in bioavailability of Ni. The presence of BX and Ni inhibited microbial activity and enzyme activities during the first 30-days. Then, from 30 days to 180 days, different trends were observed according to the condition: microbial activity was stimulated with BX alone while it was inhibited with Ni/BX mixture. This observation was supported by the fact that the inhibitory ratio (I) was higher for Ni/BX mixture than BX alone. Results showed that the sensitivity to one or both contaminants followed the order: urease (UA) > invertase (INV). EXC fraction of Ni/BX mixture were significantly correlated with UA, INV, I, peak power (Ppeak) and peak time (Tpeak), respectively (p < 0.01), suggesting that Ni bioavailability might explain the Ni toxicity against microbial communities under combined pollution conditions. Such observations allow us to better understand toxic effects of Ni pollution when accompanied with BX, facilitating precisely evaluation of potential risks in mining areas.


Assuntos
Níquel/farmacocinética , Níquel/toxicidade , Microbiologia do Solo , Poluentes do Solo/farmacocinética , Poluentes do Solo/toxicidade , Tionas/toxicidade , Disponibilidade Biológica , Calorimetria , Mineração , Solo , Urease/metabolismo , beta-Frutofuranosidase/metabolismo
11.
Chemosphere ; 239: 124794, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31521929

RESUMO

Cadmium (Cd) pollution is considered one of the global environmental issues due to its adverse effects on plant and human health. With the rapid development of nanotechnology and the practical application of engineered nanoparticles (ENPs) in agriculture, the mechanisms underlying the interactions between NPs and heavy metal on their uptake, accumulation, and phytotoxicity in crops are still not fully understood. Therefore, the impact of TiO2 NPs (0, 100, 250 mg/L) and Cd (0, 50 µM) co-exposure on hydroponic maize (Zea mays L.) was determined under two exposure modes. Results showed that root co-exposure to TiO2 NPs and 100 mg/L Cd significantly enhanced Cd uptake and produced greater phytotoxicity in maize than foliar exposure to TiO2 NPs. Meanwhile, plant dry weight and chlorophyll content showed a reduction of 45.3% and 50.5%, respectively, when compared with single Cd treatment. In addition, the accumulation of Ti in shoots and roots increased by 1.61 and 4.29 times, respectively when root exposure to 250 mg/L TiO2 NPs. By contrast, foliar exposure of TiO2 NPs could markedly decrease shoot Cd contents from 15.2% to 17.8% and had a stronger influence on alleviating Cd-induced toxicity via increasing superoxide dismutase (SOD) and glutathione S-transferase (GST) activities and upregulating several metabolic pathways, including galactose metabolism and citrate cycle, alanine, aspartate and glutamate metabolism, as well as glycine, serine and threonine metabolism. This study provides a new strategy for the application of TiO2 NPs in crop safety production in Cd contaminated soils.


Assuntos
Cádmio/toxicidade , Poluentes do Solo/toxicidade , Titânio/farmacologia , Zea mays/efeitos dos fármacos , Aminoácidos/metabolismo , Cádmio/farmacocinética , Clorofila/metabolismo , Produtos Agrícolas/metabolismo , Galactose/metabolismo , Glutationa Transferase/metabolismo , Hidroponia , Nanopartículas Metálicas/administração & dosagem , Nanopartículas Metálicas/química , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Plântula/metabolismo , Poluentes do Solo/farmacocinética , Superóxido Dismutase/metabolismo , Titânio/administração & dosagem , Titânio/farmacocinética , Zea mays/metabolismo
12.
Ecotoxicol Environ Saf ; 186: 109748, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31606640

RESUMO

Oral ingestion is the main exposure pathway through which humans ingest trace metals in the soil, particularly for children. Metals in different soil particle size fractions may vary in terms of concentration and properties. Urban school/kindergarten soil samples were collected from three cities: Lanzhou in northwest China, Wuhan in central China, and Shenzhen in southeast China. Soil samples were classified according to particle size (<63 µm, 63-150 µm, 150-250 µm, and 250-2000 µm) to estimate the effects of soil particle size on the total content and bioaccessibility of metals (Cd, Cr, Cu, Ni, Pb, and Zn). Based on the results, we assessed whether the standard size <150 µm (containing < 63 µm and 63-150 µm), recommended by the Technical Review Workgroup (TRW) of the Environmental Protection Agency (EPA), and <250 µm (containing < 63 µm, 63-150 µm, and 150-250) recommended by the Bioaccessibility Research Group of Europe (BARGE), are suitable where the largest proportion adhering to hands is the finest soil (<63 µm). The results showed that different metals exhibited different relationships between soil particle size and content and between soil particle size and bioaccessibility. Pb and Zn generally exhibited the greatest bioaccessibility in the coarsest particle sizes (250-2000 µm); whereas the highest Ni bioaccessibility occurred in the finest sizes (<63 µm); the bioaccessibility of other metals did not exhibit any obvious relationships with particle size. When assessing health risks using bioaccessible metal content in the recommended soil particle size ranges (<150 µm and <250 µm) and in finer particles (<63 µm), the results for noncarcinogenic risks to children exhibited no obvious difference, while the actual carcinogenic risks may be underestimated with the use of soil particle size ranges < 150 µm and <250 µm. Therefore, when choosing an optimal particle size fraction to evaluate the health risk of oral soil ingestion, we recommend the use of the bioaccessible metal content in <63 µm soil fraction.


Assuntos
Saúde da Criança , Monitoramento Ambiental/métodos , Metais Pesados/farmacocinética , Tamanho da Partícula , Poluentes do Solo/farmacocinética , Solo/química , Oligoelementos/farmacocinética , Disponibilidade Biológica , Criança , China , Cidades , Monitoramento Ambiental/normas , Europa (Continente) , Humanos , Metais Pesados/efeitos adversos , Metais Pesados/análise , Neoplasias/etiologia , Medição de Risco , Poluentes do Solo/efeitos adversos , Poluentes do Solo/análise , Oligoelementos/efeitos adversos , Oligoelementos/análise
13.
Chemosphere ; 237: 124540, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31549654

RESUMO

Lead can be immobilized in contaminated soils by phosphate rock (PR) amendment, but its efficiency is generally limited by low solubility of PR. Our study aimed to elucidate whether phosphate solubilizing bacteria (PSB) can promote Pb immobilization through PR solubilization. Results showed that P. ananatis HCR2 and B. thuringiensis GL-1 could effectively solubilize PR by producing citric, glucose, and α-Ketoglutaric acids. In broth assay, phosphate solubilized from PR by PSB rapidly reacted with Pb2+ and formed insoluble lead compounds, as confirmed by scanning electron microscope, energy dispersive X-ray, and X-ray photoelectron spectroscopy. Pot experiment using lettuce (Lactuca sativa L.) and diffusive gradients in thin films (DGT) verified the effectiveness of soil remediation using PR amendment and PSB inoculation, as plant shoot biomass and net photosynthetic rate as well as soil bioavailable phosphate concentration have significantly increased, while the phytoavailability of Pb, Cd, and Zn greatly reduced. This study suggested that PR amendment combined with PSB inoculation could be applied for remediation of agricultural fields contaminated with multiple heavy metals.


Assuntos
Recuperação e Remediação Ambiental/métodos , Chumbo/química , Fosfatos/química , Microbiologia do Solo , Poluentes do Solo/química , Bacillus thuringiensis/fisiologia , Disponibilidade Biológica , Chumbo/farmacocinética , Alface/efeitos dos fármacos , Alface/crescimento & desenvolvimento , Alface/fisiologia , Metais Pesados/análise , Metais Pesados/farmacocinética , Pantoea/fisiologia , Espectroscopia Fotoeletrônica , Fotossíntese/fisiologia , Brotos de Planta/crescimento & desenvolvimento , Solo/química , Poluentes do Solo/análise , Poluentes do Solo/farmacocinética , Solubilidade , Espectrometria por Raios X
14.
Chemosphere ; 237: 124549, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31549661

RESUMO

The addition of organic amendment in soils affected by residual pollution of potentially harmful elements (PHEs) is evaluated. The area was polluted twenty years ago and remediation actions were intensively applied, but evidence of pollution are still detected in some sectors. The amendment application produces significant changes in the main soil properties and modifies the mobility and availability of the pollutants. In general, Cu, Zn, Cd and Pb, showed a significant reduction in soluble and exchangeable forms after the vermicompost addition (percentage of reduction ranging from 59% for soluble Pb to 95% for exchangeable Zn), both in highly (UVS) as in moderately (VS1) polluted soils. This reduction is strongly related to the rise in OC content and pH. Arsenic presented no significant reduction or even an increase in soluble forms in moderately polluted soils (VS1), where the competing effects of OC and phosphorous could be responsible for this increase. Pb also showed an increase in availability after vermicompost application, probably related to the competing effect of Mg2+ coming from the organic amendment. The less mobile forms (those extracted with oxalic-oxalate, pyrophosphate and EDTA), indicate that vermicompost application reduce medium-long term mobility to similar values of those found in less polluted soils (VS2); anyway, an increase in available forms of Pb and As was detected in some cases, indicating a potential risk of toxicity that should be monitored over time.


Assuntos
Compostagem , Recuperação e Remediação Ambiental/métodos , Metais Pesados/análise , Poluentes do Solo/análise , Solo/química , Animais , Carbono , Fracionamento Químico/métodos , Difosfatos/química , Ácido Edético/química , Cavalos , Concentração de Íons de Hidrogênio , Esterco , Metais Pesados/farmacocinética , Poluentes do Solo/farmacocinética , Espanha
15.
Environ Sci Pollut Res Int ; 26(32): 32957-32966, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31512134

RESUMO

Better understanding of microbial activity in the rhizosphere soils associated with lead (Pb) uptake by plants may help with the phytoremediation of Pb-contaminated soils. In this work, the effects of Pb exposure (0, 200, 400, 600, 800 mg kg-1) on Pb accumulation and soil microbial activity in the rhizosphere of the mining ecotype (ME) and corresponding non-mining ecotype (NME) of Athyrium wardii (Hook.) Makino were investigated through a pot experiment. Although the plant growth of the two ecotypes was inhibited under Pb stress, the ME showed a less biomass decrease (12.6-44.0%) for aboveground than the NME, showing a greater tolerance to Pb stress. Pb concentrations as well as Pb accumulation in the two ecotypes showed an increasing trend with increasing soil Pb concentrations. The ME presented greater Pb accumulation ability than the NME, especially in underground parts. Pb availability in the rhizosphere soils of the two ecotypes after harvest decreased compared with those before transplantation. Available Pb in the rhizosphere of the ME was 1.4-4.8 times higher than that of the NME under exposure to 200-800 mg kg-1 Pb. The ME shows a greater ability to mobilize Pb in the rhizosphere soils. Pb exposure resulted in an inhibition of microbial activity in the rhizosphere of the two ecotypes. The ME demonstrated greater soil respiration and microbial biomass carbon (MBC) in the rhizosphere than the NME when treated with 200-800 mg kg-1 Pb. The ME showed a less decrease for MBC and a less increase for metabolic quotient in the rhizosphere soils than the NME when exposed to Pb generally. Microorganisms in the rhizosphere soils of the ME seem to be much more adapted to Pb stress, thus showing a great benefit for Pb accumulation and the phytostabilization of Pb-contaminated soils by the ME.


Assuntos
Chumbo/farmacocinética , Mineração , Microbiologia do Solo , Poluentes do Solo/farmacocinética , Traqueófitas/fisiologia , Adaptação Fisiológica , Disponibilidade Biológica , Biomassa , China , Ecótipo , Chumbo/análise , Rizosfera , Solo/química , Poluentes do Solo/análise , Traqueófitas/efeitos dos fármacos
16.
Mar Pollut Bull ; 149: 110576, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546111

RESUMO

Samples from 13 beaches along the northern Spanish coast, a region with a history of heavy industries, were first screened to identify signs of pollution. High concentrations of Hg and Ba on Vega beach were found, both elements belong to the fluorite ore paragenesis, mined in the surroundings. Samples of beach and fluvial sediments, and nearby soils were collected in Vega beach area to address potential Hg pollution, fate and sources. Most samples showed a similar pollutants fingerprint to that of beach samples, especially those taken from white dunes, registering notable Hg concentrations. Hg was enriched in the finer fractions, and overall the main input was attributed to the mining waste discharged along the coast in the past. Although a specific risk assessment and study of the submerged sediments are advisable for this area, Hg bioavailability and methylation were low, thus indicating that this metal poses a reduced environmental risk.


Assuntos
Mercúrio/análise , Mineração , Poluentes do Solo/análise , Poluentes Químicos da Água/análise , Bário/análise , Praias , Disponibilidade Biológica , Monitoramento Ambiental , Sedimentos Geológicos/análise , Mercúrio/farmacocinética , Metais/análise , Poluentes do Solo/farmacocinética , Espanha , Poluentes Químicos da Água/farmacocinética
17.
Environ Sci Pollut Res Int ; 26(31): 31822-31833, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31487012

RESUMO

Remediation of heavy metal-contaminated soils is essential for safe agricultural or urban land use, and phytoremediation is among the most effective methods. The success of phytoremediation relies on the size of the plant biomass and bioavailability of the metal for plant uptake. This research was carried out to determine the effect of Ethylenediaminetetraacetic acid (EDTA) ligand and Cu-resistant plant growth-promoting rhizobacteria (PGPR) on phytoremediation efficiency of selected plants as well as fractionation and bioavailability of copper (Cu) in a contaminated soil. The test conditions included three plant species (maize: Zea mays L., sunflower: Helianthus annuus L., and pumpkin: Cucurbita pepo L.) and six treatments, comprising two PGPR strains (Pseudomonas cedrina K4 and Stenotrophomonas sp. A22), two PGPR strains with EDTA, EDTA, and control (without PGPR and EDTA). The combination of EDTA and PGPR enhanced the Cu concentration in both shoot and root tissues and increased the plant biomass. The Cu specific uptake was at a maximum level in the shoots of pumpkin plants when treated with the PGPR strain K4 + EDTA (202 µg pot-1), and the minimum amount of Cu was recorded for sunflower with no PGPR or EDTA addition (29.6 µg pot-1). The result of the PGPR-EDTA treatments showed that the combined application of EDTA and PGPR increased the shoot Cu-specific uptake approximately fourfold in pumpkin. Pumpkin with the highest shoot Cu specific uptake and maize with the highest root Cu specific uptake were the most effective plants in phytoextraction and phytostabilization, respectively. The effectiveness of different PGPR-EDTA treatments in increasing Cu specific uptake by crop plants was assessed by measuring the amount of Cu extracted from the rhizosphere soil adhering to the roots of crop species, by the use of the single extractants Diethylenetriamine pentaacetic acid (DTPA), H2O, NH4NO3, and NH4OAc. PGPR-EDTA treatments increased the amount of water-extractable Cu from rhizosphere soils more than ten times that of the control. The combined application of the EDTA and PGPR reduced the carbonated Fe and Mn oxide-bound Cu in the contaminated soil, and increased the soluble and exchangeable concentration of Cu. Pumpkin, with high shoot biomass and the highest shoot Cu specific uptake was found to be the most effective field crop in phytoextraction of Cu from the contaminated soil. The results of this pot study demonstrated that the EDTA+PGPR treatment could play an important role in increasing the Cu bioavailability and specific uptake by plants, and thus increasing the phytoremediation efficiency of plants in Cu-contaminated areas.


Assuntos
Biodegradação Ambiental/efeitos dos fármacos , Cobre/toxicidade , Ácido Edético/farmacologia , Pseudomonas/efeitos dos fármacos , Poluentes do Solo/toxicidade , Inoculantes Agrícolas , Disponibilidade Biológica , Biomassa , Cobre/análise , Cobre/farmacocinética , Cucurbita/efeitos dos fármacos , Cucurbita/microbiologia , Helianthus/efeitos dos fármacos , Helianthus/microbiologia , Brotos de Planta/efeitos dos fármacos , Pseudomonas/fisiologia , Rizosfera , Poluentes do Solo/farmacocinética , Zea mays/efeitos dos fármacos , Zea mays/microbiologia
18.
Chemosphere ; 236: 124406, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31545203

RESUMO

Pot experiments were conducted under abiotic conditions to investigate the interactive influence of decabromodiphenyl ether (BDE-209) and lead (Pb) on the seed germination, germ length, root exudation and physiological characteristics of tall fescue (Festuca arundinaceae), and the uptake, accumulation of Pb and BDE-209 in the plant tissues. Results show that seed germination and germ length were impacted by Pb but less influenced by BDE-209. BDE-209 spiking (10 and 50 mg/L) could alleviate the toxicity of high Pb concentration on seed germination and growth. The chlorophyll content was significantly increased at 500 mg/kg Pb but declined at 2000 mg/kg Pb. Low-level Pb contamination (500 mg/kg) activated antioxidase activity; however, 2000 mg/kg Pb significantly reduced the antioxidase activity. Plant biomass slightly decreased at 500 mg/kg Pb but significantly declined at 2000 mg/kg Pb. The addition of a moderate dosage of BDE-209 (10-50 mg/kg) lessened Pb phytotoxicity, leading to improved plant growth relative to the case of Pb spiking alone. The exudate secretion was significantly enhanced by Pb addition, but BDE-209 spiking only caused slightly increased secretion. Pb could interfere with BDE-209 adsorption and translocation of tall fescue by affecting physiological behavior of the plant, but BDE-209 exhibited little influence on the Pb fate in the plant. Overall, BDE-209 had slight interference on the impact of Pb towards tall fescue. The results demonstrate the complex interactive effects of organic pollutants and heavy metals in the soil-plant system.


Assuntos
Festuca/efeitos dos fármacos , Éteres Difenil Halogenados/toxicidade , Chumbo/toxicidade , Poluentes do Solo/toxicidade , Biomassa , Clorofila/metabolismo , Ecotoxicologia/métodos , Festuca/crescimento & desenvolvimento , Festuca/metabolismo , Germinação/efeitos dos fármacos , Éteres Difenil Halogenados/farmacocinética , Chumbo/farmacocinética , Exsudatos de Plantas/análise , Exsudatos de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Poluentes do Solo/farmacocinética
19.
Environ Sci Pollut Res Int ; 26(29): 30386-30398, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31440969

RESUMO

A study of the impact of an abandoned lead (Pb) mine ("Las Musas"), located in SW Spain, on the contamination of the surface soil and pastures in its vicinity revealed the presence of widely distributed, high levels of Pb contamination. The total Pb concentrations in soils sampled at distances from 3 to 998 m from the mine ranged between 129 and 1053 mg/kg, when it has been reported that non-polluted soils have concentrations of 29-40 mg/kg. These exceed the maximum tolerable levels in agricultural soils for the protection of environmental and human health as established in international and regional regulations. While the concentrations of potentially bioavailable Pb in the soils also surpassed the regulatory levels, the effective bioavailable fractions were low. The Pb concentrations measured in native plants ranged from 1.70 to 129 mg/kg dry weight, with Cynosurus echinatus, Philadelphus coronarius, and Fraxinus angustifolia being the species that bioaccumulated the greatest concentrations of this metal. Estimation of the environmental risk to wildlife and livestock grazing in the studied area showed no potential toxicity for these animals.


Assuntos
Chumbo/análise , Plantas/química , Poluentes do Solo/análise , Agricultura , Animais , Animais Selvagens , Monitoramento Ambiental , Humanos , Chumbo/farmacocinética , Chumbo/toxicidade , Gado , Mineração , Medição de Risco , Solo/química , Poluentes do Solo/farmacocinética , Poluentes do Solo/toxicidade , Espanha
20.
Environ Sci Pollut Res Int ; 26(29): 30472-30484, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31444718

RESUMO

The supply of potassium (K) is a strategy to increase the tolerance of plants exposed to Cd toxicity. The aim of this study was to verify the influence of K on the growth and potential of Tanzania guinea grass (Panicum maximum Jacq. cv. Tanzania (syn. Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs)) for Cd phytoextraction as well as to evaluate nutritional attributes of this grass under conditions of Cd stress. The experiment was conducted in a randomized complete block design, using a 3 × 4 factorial arrangement, with three replications. Three rates of K (0.4, 6.0, and 11.6 mmol L-1) were combined with four rates of Cd (0.0, 0.5, 1.0, and 1.5 mmol L-1) in nutrient solution. Two plant growth periods were evaluated. The increase in K supply to plants exposed to Cd rates of up to 1.0 mmol L-1 caused increase in morphogenic and production attributes, as well as reduction in tiller mortality rate, in the second growth period. K concentrations (in both harvests) increased, while calcium and magnesium concentrations in the second harvest decreased with increasing Cd rates. The high availability of Cd (1.5 mmol L-1) in the nutrient solution caused decrease in relative chlorophyll index (RCI) in both harvests. The high supply of K to plants exposed to Cd resulted in high shoot dry mass production, reducing Cd concentration in the photosynthetic tissues (which means great tolerance of the plant) and increasing the accumulation of this metal in the shoots that can be harvested. Therefore, K increases the Cd phytoextraction capacity of Tanzania guinea grass.


Assuntos
Cádmio/isolamento & purificação , Cádmio/toxicidade , Panicum/efeitos dos fármacos , Potássio/farmacologia , Biodegradação Ambiental , Cádmio/farmacocinética , Cálcio/metabolismo , Cálcio/farmacocinética , Clorofila/metabolismo , Magnésio/metabolismo , Magnésio/farmacocinética , Panicum/fisiologia , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Potássio/farmacocinética , Poluentes do Solo/isolamento & purificação , Poluentes do Solo/farmacocinética , Poluentes do Solo/toxicidade , Estresse Fisiológico
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