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1.
Ecotoxicol Environ Saf ; 220: 112411, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34111661

RESUMO

This study focused on the effects of eight medicinal plant extracts on Solanum nigrum L. potential to accumulate Cd and Pb from soil. These medicinal plants were common and relatively cheap. The eight 10% water extracts were made from the peel of Citrus reticulata Blanco (PCR), fruit of Phyllanthus emblica L. (FPE), root of Pueraria Lobata (Willd.) Ohwi (RPL), rhizome of Polygonatum sibiricum Red (RPS), root of Astragalus propinquus Schischkin (RAP), bud of Hemerocallis citrina Baroni (BHC), seed of Nelumbo nucifera Gaertn (SNN) and fruit of Prunus mume (Sieb.) Sieb.etZuce (FPM). The results showed that among all exposures, the treatment with FPE resulted in the significant increase (p < 0.05) of Cd and Pb concentration in shoots and roots of S. nigrum by 32.5% and 65.2% for Cd, and 38.7% and 39.6% for Pb. The biomasses of S. nigrum in all plant extract treatments were not significantly changed (p < 0.05) compared to the control (CK). The Cd and Pb extraction rates of S. nigrum in FPE treatment were increased respectively by 60.5% and 40.5% compared to CK. Though the treatment with EDTA significantly improved (p < 0.05) the concentration of Cd and Pb of S. nigrum, the Cd and Pb masses (ug plant-1) of S. nigrum did not show any significant difference compared to the CK due to the significant decrease in the shoot (20.4%) and root (22.0%) biomasses. The chelative role of FPE might be relation with its higher polyphenolic compounds. However, not sure if the contents of polyphenolic compounds was the only differences between FPE and other additives. Thus, some unknown organic matters might also play active role. This study provided valuable information on improving the phytoremediation potential of hyperaccumulator.


Assuntos
Metais Pesados/metabolismo , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Poluentes do Solo/metabolismo , Solanum nigrum/efeitos dos fármacos , Biodegradação Ambiental/efeitos dos fármacos , Biomassa , Quelantes/química , Quelantes/farmacologia , Extratos Vegetais/química , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/metabolismo , Solanum nigrum/metabolismo
2.
Ecotoxicol Environ Saf ; 221: 112437, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34153540

RESUMO

Agricultural soils are receiving higher inputs of trace elements (TEs) from anthropogenic activities. Application of nanoparticles (NPs) in agriculture as nano-pesticides and nano-fertilizers has gained rapid momentum worldwide. The NPs-based fertilizers can facilitate controlled-release of nutrients which may be absorbed by plants more efficiently than conventional fertilizers. Due to their large surface area with high sorption capacity, NPs can be used to reduce excess TEs uptake by plants. The present review summarizes the effects of NPs on plant growth, photosynthesis, mineral nutrients uptake and TEs concentrations. It also highlights the possible mechanisms underlying NPs-mediated reduction of TEs toxicity at the soil and plant interphase. Nanoparticles are effective in immobilization of TEs in soil through alteration of their speciation and improving soil physical, chemical, and biological properties. At the plant level, NPs reduce TEs translocation from roots to shoots by promoting structural alterations, modifying gene expression, and improving antioxidant defense systems. However, the mechanisms underlying NPs-mediated TEs uptake and toxicity reduction vary with NPs type, mode of application, time of NPs exposure, and plant conditions (e.g., species, cultivars, and growth rate). The review emphasizes that NPs may provide new perspectives to resolve the problem of TEs toxicity in crop plants which may also reduce the food security risks. However, the potential of NPs in metal-contaminated soils is only just starting to be realized, and additional studies are required to explore the mechanisms of NPs-mediated TEs immobilization in soil and uptake by plants. Such future knowledge gap has been highlighted and discussed.


Assuntos
Nanopartículas , Plantas/efeitos dos fármacos , Oligoelementos/metabolismo , Oligoelementos/toxicidade , Agricultura , Metais/metabolismo , Metais/toxicidade , Raízes de Plantas/metabolismo , Plantas/metabolismo , Solo/química , Poluentes do Solo/metabolismo , Poluentes do Solo/toxicidade
3.
Ecotoxicol Environ Saf ; 221: 112432, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34166937

RESUMO

The intensive and long-term use of atrazine in agriculture has resulted in serious environmental pollution and consequently endangered ecosystem and human health. Soil microorganisms play an important role in atrazine degradation. However, their degradation efficiencies are relatively low due to their slow growth and low abundance, and manure amendment as a practice to improve soil nutrients and microbial activities can solve these problems. This study investigated the roles of goat manure in atrazine degradation performance, metabolites and bacterial community structure. Our results showed that atrazine degradation efficiencies in un-amended soils were 26.9-35.7% and increased to 60.9-84.3% in goat manure amended treatments. Hydroxyatrazine pathway was not significantly altered, whereas deethylatrazine and deisopropylatrazine pathways were remarkably enhanced in treatments amended with manure by encouraging the N-dealkylation of atrazine side chains. In addition, goat manure significantly increased soil pH and contents of organic matters and humus, explaining the change of atrazine metabolic pathway. Nocardioides, Sphingomonas and Massilia were positively correlated with atrazine degradation efficiency and three metabolites, suggesting their preference in atrazine contaminated soils and potential roles in atrazine degradation. Our findings suggested that goat manure acts as both bacterial inoculum and nutrients to improve soil microenvironment, and its amendment is a potential practice in accelerating atrazine degradation at contaminated sites, offering an efficient, cheap, and eco-friendly strategy for herbicide polluted soil remediation.


Assuntos
Atrazina/metabolismo , Biodegradação Ambiental , Esterco/microbiologia , Microbiologia do Solo , Animais , Atrazina/análise , Bactérias/metabolismo , Ecossistema , Cabras , Herbicidas/análise , Herbicidas/metabolismo , Solo/química , Poluentes do Solo/análise , Poluentes do Solo/metabolismo
4.
Ecotoxicol Environ Saf ; 220: 112368, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34082243

RESUMO

A field investigation on the content of heavy metals in soils and dominant plants was conducted in three sites (A<0.5 km, B<1.0 km, C<1.5 km) with different distances of mine tailings. The spatial distribution of heavy metals and the accumulation in plants were compared, and the candidate species for ecosystem restoration were selected. The results indicated that the soil was polluted by chromium (Cr), Cadmium (Cd), copper (Cu), nickel (Ni) in varying degrees, which is 2.07, 2.60, 1.79, and 4.49 times higher than the Class-Ⅱ standard in China. The concentrate of Ni, Cd, and Zinc (Zn) increased, while Cr, Lead (Pb), and Cu decreased with the distance from the mine tailings. 73 species (34 families) were found and mainly herbaceous plants. The concentrate of Cd, Cu, Cr, and Ni in 29 dominant plants were measured and 66.67%, 21.43%, 100%, 47.62% plants exceeded the normal concentration range. Based on the comparative analysis of heavy metal content, bioconcentration factor, and translocation factor in plants, Polygonum capitatum has good phytoextraction ability, Boehmeria nivea, Chrysanthemum indicum, Miscanthus floridulus, Conyza canadensis, Rubus setchuenensis, Senecio scandens, and Arthraxon hispidus showed remarkable phytostabilization abilities of Cr, Cd, Ni, and Cu, which can be used as potential phytoremediation candidate.


Assuntos
Metais Pesados/metabolismo , Mineração , Plantas/metabolismo , Poluentes do Solo/metabolismo , Bioacumulação , Biodegradação Ambiental , China , Metais Pesados/análise , Plantas/classificação , Solo/química , Poluentes do Solo/análise
5.
Ecotoxicol Environ Saf ; 220: 112392, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34102395

RESUMO

Understanding the molecular mechanisms of cadmium (Cd) tolerance and accumulation in plants is important to address Cd pollution. In the present study, we performed comparative transcriptome analysis to identify the Cd response processes in the roots of two turnip landraces, KTRG-B14 (high-Cd accumulation) and KTRG-B36 (low-Cd accumulation). Two common enhanced processes, glutathione metabolism and antioxidant system, were identified in both landraces. However, some differential antioxidant processes are likely employed by two landraces, namely, several genes encoding peptide methionine sulfoxide reductases and thioredoxins were up-regulated in B14, whereas flavonoid synthesis was potentially induced to fight against oxidative stress in B36. In addition to the commonly upregulated ZINC INDUCED FACILITATOR 1-like gene in two landraces, different metal transporter-encoding genes identified in B14 (DETOXIFICATION 1) and B36 (PLANT CADMIUM RESISTANCE 2-like, probable zinc transporter 10, and ABC transporter C family member 3) were responsible for Cd accumulation and distribution in cells. Several genes that encode extensins were specifically upregulated in B14, which may improve Cd accumulation in cell walls or regulate root development to absorb more Cd. Meanwhile, the induced high-affinity nitrate transporter 2.1-like gene was also likely to contribute to the higher Cd accumulation in B14. However, Cd also caused some toxic symptoms in both landraces. Cd stress might inhibit iron uptake in both landraces whereas many apoenzyme-encoding genes were influenced in B36, which may be attributed to the interaction between Cd and other metal ions. This study provides novel insights into the molecular mechanism of plant root response to Cd at an early stage. The transporters and key enzymes identified in this study are helpful for the molecular-assisted breeding of low- or high-Cd-accumulating plant resources.


Assuntos
Brassica napus/genética , Cádmio/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Proteínas de Plantas/genética , Raízes de Plantas/metabolismo , Poluentes do Solo/metabolismo , Antioxidantes/metabolismo , Biodegradação Ambiental , Brassica napus/metabolismo , Glutationa/metabolismo , Glicoproteínas/genética , Glicoproteínas/metabolismo , Ferro/metabolismo , Estresse Oxidativo , Proteínas de Plantas/metabolismo , Transcriptoma
6.
Ecotoxicol Environ Saf ; 220: 112407, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34119926

RESUMO

2,4,6-trinitrotoluene (TNT) and cobalt (Co) contaminants have posed a severe environmental problem in many countries. Phytoremediation is an environmentally friendly technology for the remediation of these contaminants. However, the toxicity of TNT and cobalt limit the efficacy of phytoremediation application. The present research showed that expressing the Acidithiobacillus ferrooxidans single-strand DNA-binding protein gene (AfSSB) can improve the tolerance of Arabidopsis and tall fescue to TNT and cobalt. Compared to control plants, the AfSSB transformed Arabidopsis and tall fescue exhibited enhanced phytoremediation of TNT and cobalt separately contaminated soil and co-contaminated soil. The comet analysis revealed that the AfSSB transformed Arabidopsis suffer reduced DNA damage than control plants under TNT or cobalt exposure. In addition, the proteomic analysis revealed that AfSSB improves TNT and cobalt tolerance by strengthening the reactive superoxide (ROS) scavenging system and the detoxification system. Results presented here serve as strong theoretical support for the phytoremediation potential of organic and metal pollutants mediated by single-strand DNA-binding protein genes. SUMMARIZES: This is the first report that AfSSB enhances phytoremediation of 2,4,6-trinitrotoluene and cobalt separately contaminated and co-contaminated soil.


Assuntos
Cobalto/metabolismo , Proteínas de Ligação a DNA/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Poluentes do Solo/metabolismo , Trinitrotolueno/metabolismo , Acidithiobacillus/genética , Arabidopsis/genética , Arabidopsis/metabolismo , Biodegradação Ambiental , Proteínas de Ligação a DNA/genética , Lolium/genética , Lolium/metabolismo , Plantas Geneticamente Modificadas/genética , Proteômica
7.
Ecotoxicol Environ Saf ; 219: 112374, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34049226

RESUMO

This study determined the degradation of lindane in soil amended with biochar to evaluate the effects of biochar aging and microbial toxicity. Two biochars were prepared at 400 and 600 °C (BC400 and BC600) and subjected to acid washing to remove nutrition (WBC400 and WBC600). After 89 days of incubation under the alternate "wet-dry" conditions, scanning electron microscopy showed that acid washing rendered biochars especially susceptible to aging with structural collapse and fragmentation, with less surface covering. Aging impeded the release of toxic substances in BC400 and BC600 with reduced toxicity to degrading microorganisms. Lindane degradation was somewhat stimulated by biochar nutrition but mainly inhibited by adsorption. Acid washing facilitated the release of toxic substances and additionally reduced lindane degradation. The variations in fatty acid saturation degree (SFA/UFA) in soils confirmed the microbial toxicity of 5% WBC400 > 5% BC400 > 5% BC600 > 5% WBC600. High-throughput DNA sequencing showed that biochar delayed the formation of dominant degrading microbial communities in soil. Lindane degradation was completed by joint Sphingomonas, Flaviolibacter, Parasegetibacter, Azoarcus, Bacillus and Anaerolinaea. These findings are helpful for better understanding the effect of biochar in soil on long-term degradation of persistent organic pollutants.


Assuntos
Carvão Vegetal/química , Hexaclorocicloexano/metabolismo , Poluentes do Solo/metabolismo , Adsorção , Biodegradação Ambiental , Solo/química , Poluentes do Solo/análise
8.
Ecotoxicol Environ Saf ; 217: 112100, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33933890

RESUMO

Studies focusing on arsenic methylation and volatilization in paddy soil, aiming to limit bioaccumulation of arsenic (As) in rice grains, have attracted global attention. In this study, we explored three aspects of these topics. First, rainwater and trace H2O2 were compared for their influence on the arsenic methylation and volatilization of paddy soil in different rice growth stages. Second, the arsenic accumulation in different parts of rice was affected by rainwater and trace H2O2. Third, we determined whether rice fields were affected by rainwater and trace H2O2. The result showed that the rainwater or trace H2O2 irrigation caused As(III) to significantly decrease and As(V) to significantly increase in soil. A similar consequence occurred in the filling stage and mature stage of rice. The arsenic volatilization rates of the rainwater and trace H2O2 irrigation were significantly higher than the control, and the arsenic volatilization of rainwater irrigation was the highest (51.0 µg m-2 d-1) in the filling stage. Compared to the control, the total arsenic and iAs of treatments decreased by 14-41% and 12-32% respectively. Finally, we found that rainwater and trace H2O2 irrigation likely increased rice fields.


Assuntos
Poluentes Atmosféricos/química , Arsênio/toxicidade , Peróxido de Hidrogênio/química , Oryza/fisiologia , Poluentes do Solo/toxicidade , Arsênio/química , Arsênio/metabolismo , Metilação , Oryza/crescimento & desenvolvimento , Solo , Poluentes do Solo/análise , Poluentes do Solo/química , Poluentes do Solo/metabolismo , Volatilização
9.
Ecotoxicol Environ Saf ; 220: 112315, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34015628

RESUMO

Particulate organic matter (POM) is an effective adsorbent for decreasing the contaminant of cadmium, but little is known about the relevant mechanisms under the effect of plant. In this work, POM were used to study the removal of Cd2+ in the initial concentration range of 0-4.46 mmol L-1 at pH 5.5, and the effect of Artemisia ordosica roots and pH on kinetics and equilibrium of cadmium adsorption on POM and soils were examined. The result indicated that adsorption kinetics fit well with the pseudo-second-order kinetic model, and the equilibrium data for Cd adsorption fit much well to the Langmuir model. The maximum adsorption capacity for POM at equilibrium corresponding to the monolayer coverage reached 0.287 mmol/g for Cd. The amount of Cd adsorbed in the POM and soil increased with the increase of pH from 4 to 8.5. The Artemisia ordosica roots decreased Cd adsorption in POM; instead, the adsorption capacity of soil for Cd was improved under the effect of Artemisia ordosica roots. The Fourier Transform Infrared spectroscopic (FTIR) analysis indicated that the complexation of POM and Cd was mainly through sulfhydryl, hydroxyl and carboxyl groups.


Assuntos
Artemisia/metabolismo , Cádmio/metabolismo , Material Particulado/química , Raízes de Plantas/metabolismo , Poluentes do Solo/química , Poluentes do Solo/metabolismo , Solo/química , Adsorção , Compostos Orgânicos/química
10.
Ecotoxicol Environ Saf ; 220: 112371, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34052759

RESUMO

Uptake of most metal nanoparticles (NPs) in organisms is assumed to be mainly driven by the bioavailability of the released ions, as has been verified in controlled and short-term exposure tests. However, the changeability of NPs and the dynamic processes which NPs undergo in the soil environment, bring uncertainty regarding their interactions with soil organisms over a long period of time. To assess the potential impacts of long-term exposure scenarios on the toxicokinetic of metal NPs, earthworms Eisenia fetida were exposed to soils spiked with pristine Ag-NP, aged Ag-NP (Ag2S-NP) and ionic Ag for nine months, and results were compared to those from a similar short-term (28 days) experiment, conducted under similar conditions. Overall, there were no statistical differences between long-term accumulation patterns in earthworms exposed to pristine Ag-NP and AgNO3, while for Ag2S-NP, the amount of Ag internalized after 9 months was five times lower than for the other treatments. Average Ag concentrations in soil pore water in all treatments did not change over time, however the soil pH decreased and electrical conductivity increased in all treatments. Metallothionein concentrations in exposed earthworms were not statistically different from levels in untreated earthworms. Finally, the short-term toxicokinetic models predicted the bioaccumulation in earthworms exposed to Ag-NP, AgNO3 after nine months on the whole. Although the bioaccumulation for Ag2S-NPs was somewhat under-predicted, the rate of accumulation of Ag2S-NPs is much lower than that of Ag-NPs or AgNO3 and thus potentially of lower concern. Nevertheless, better understanding about the exposure kinetics of Ag2S-NP would help to address potential nano-specific toxicokinetic and toxicodynamics, also of other sulfidized metal NPs.


Assuntos
Íons/metabolismo , Nanopartículas Metálicas , Oligoquetos/metabolismo , Prata/metabolismo , Poluentes do Solo/metabolismo , Solo/química , Animais , Bioacumulação , Disponibilidade Biológica , Transporte Biológico , Metalotioneína , Compostos de Prata/metabolismo , Toxicocinética , Água
11.
Ecotoxicol Environ Saf ; 220: 112370, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34058673

RESUMO

A 6 weeks pot culture experiment was carried out to investigate the stabilization effects of a modified biochar (BCM) on metals in contaminated soil and the uptake of these metals by wheat seedlings. The results showed that the application of BCM significantly increased the soil fertility, the biomass of wheat seedling roots increased by more than 50%, and soil dehydrogenase (DHA) and catalase (CAT) activities increased by 369.23% and 12.61%, respectively. In addition, with the application of BCM, the diethylenetriaminepentaacetic acid extractable (DTPA-extractable) Cd, Pb, Cu and Zn in soil were reduced from 2.34 to 0.38 mg/kg, from 49.27 to 25.65 mg/kg, from 3.55 mg/kg to below the detection limit and from 4.05 to 3.55 mg/kg, respectively. Correspondingly, the uptake of these metals in wheat roots and shoots decreased by 62.43% and 79.83% for Cd, 73.21% and 66.32% for Pb, 57.98% and 68.92% for Cu, and 40.42% and 43.66% for Zn. Furthermore, BCM application decreased the abundance and alpha diversity of soil bacteria and changed the soil bacterial community structure dramatically. Overall, BCM has great potential for the remediation of metal-contaminated soils, but its long-term impact on soil metals and biota need further research.


Assuntos
Bactérias/efeitos dos fármacos , Carvão Vegetal/farmacologia , Metais Pesados/metabolismo , Plântula/metabolismo , Poluentes do Solo/metabolismo , Solo/química , Triticum/efeitos dos fármacos , Disponibilidade Biológica , Biomassa , Cádmio/metabolismo , Poluição Ambiental , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Microbiologia do Solo , Triticum/crescimento & desenvolvimento , Triticum/metabolismo
12.
Int J Mol Sci ; 22(6)2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33802057

RESUMO

Heavy metals polluting the 100-year-old waste heap in Boleslaw (Poland) are acting as a natural selection factor and may contribute to adaptations of organisms living in this area, including Trifolium repens and its root nodule microsymbionts-rhizobia. Exopolysaccharides (EPS), exuded extracellularly and associated with bacterial cell walls, possess variable structures depending on environmental conditions; they can bind metals and are involved in biofilm formation. In order to examine the effects of long-term exposure to metal pollution on EPS structure and biofilm formation of rhizobia, Rhizobium leguminosarum bv. trifolii strains originating from the waste heap area and a non-polluted reference site were investigated for the characteristics of the sugar fraction of their EPS using gas chromatography mass-spectrometry and also for biofilm formation and structural characteristics using confocal laser scanning microscopy under control conditions as well as when exposed to toxic concentrations of zinc, lead, and cadmium. Significant differences in EPS structure, biofilm thickness, and ratio of living/dead bacteria in the biofilm were found between strains originating from the waste heap and from the reference site, both without exposure to metals and under metal exposure. Received results indicate that studied rhizobia can be assumed as potentially useful in remediation processes.


Assuntos
Biofilmes , Metais Pesados/metabolismo , Polissacarídeos Bacterianos/metabolismo , Rhizobium leguminosarum/fisiologia , Poluentes do Solo/metabolismo , Trifolium/microbiologia , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento
13.
Ecotoxicol Environ Saf ; 217: 112268, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33930768

RESUMO

Cadmium (Cd) is among the most toxic heavy metals in soils. The ways by which tomato plants inoculated with a phosphate-solubilizing bacterium (PSB) respond to Cd and regulate gene expression remain unclear. We investigated hormone metabolism and genes involved in Cd resistance in tomato seedlings inoculated with the PSB strain N3. Cd inhibited tomato plant growth and nutrient uptake and increase in dry weight. Compared with Cd treatment, N3 inoculation inhibited the accumulation of Cd in the shoots and roots, and the root dry weight significantly increased by 30.50% (P < 0.05). The nitrogen and potassium contents in the roots of seedlings treated with N3 increased, and the phosphorus levels were the same as those in the control. N3 decreased the rate of Zn2+ absorption but increased Fe3+ absorption in the roots, and the amount of accumulated Cd increased with Zn2+ uptake. The concentrations of hormones (indole-3-acetic acid, IAA; zeatin, ZEA; and jasmonic acid, JA) increased under Cd stress, whereas inoculation with N3 reduced IAA and ZEA levels. In the comparison between N3 + Cd and Cd treatments, the highest number of up- and downregulated genes was obtained. Pathways involved in signaling response, photosynthesis, phenylpropanoid biosynthesis, and DNA replication and the photosynthesis-antenna proteins pathway play important roles in the responses and adaptation of seedlings to Cd. Inoculation with N3 alleviates Cd stress in tomato seedlings. The present study provides new insights into the differentially expressed genes related to interaction between PSB and tomato exposed to Cd in soils.


Assuntos
Burkholderia/fisiologia , Cádmio/toxicidade , Lycopersicon esculentum/fisiologia , Fosfatos/metabolismo , Poluentes do Solo/toxicidade , Cádmio/metabolismo , Expressão Gênica , Regulação da Expressão Gênica , Ácidos Indolacéticos , Lycopersicon esculentum/efeitos dos fármacos , Lycopersicon esculentum/microbiologia , Fotossíntese , Desenvolvimento Vegetal , Raízes de Plantas/metabolismo , Plântula/metabolismo , Solo , Poluentes do Solo/metabolismo
14.
Ecotoxicol Environ Saf ; 217: 112217, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33862431

RESUMO

Microplastics are widespread in freshwater environments, their biological effects and combined effects of other pollutants have attracted extensive attention. In this study, we investigated the adsorption properties of heavy metals onto polystyrene (PS) microplastics as well as the bioavailability and toxicity of microplastics and heavy metals by hydroponic wheat seedlings experiment. Results showed that PS microplastics (0.5 µm, 100 mg/L) had no significant effect on wheat seedlings growth, photosynthesis, and reactive oxygen species (ROS) content. However, PS microplastics could adsorb copper and cadmium, with a predominantly chemisorption. The accumulation of copper and cadmium in wheat seedlings reduced in the presence of PS microplastics, which meant the toxic effect by heavy metals might be mitigated. Compared with single heavy metals treatments, the combination of PS microplastics and heavy metals increased chlorophyll content, enhanced photosynthesis and reduced the accumulation of ROS. These findings suggest that PS microplastics (0.5 µm, 100 mg/L) have a mitigating effect on the bioavailability and toxicity of copper and cadmium.


Assuntos
Cádmio/toxicidade , Cobre/toxicidade , Microplásticos/toxicidade , Poluentes do Solo/toxicidade , Triticum/fisiologia , Adsorção , Disponibilidade Biológica , Transporte Biológico , Clorofila , Hidroponia , Metais Pesados/toxicidade , Microplásticos/metabolismo , Fotossíntese , Plásticos , Poliestirenos , Plântula/efeitos dos fármacos , Plântula/fisiologia , Poluentes do Solo/metabolismo
15.
Nat Commun ; 12(1): 2466, 2021 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-33927199

RESUMO

Microorganisms play vital roles in modulating organic matter decomposition and nutrient cycling in soil ecosystems. The enzyme latch paradigm posits microbial degradation of polyphenols is hindered in anoxic peat leading to polyphenol accumulation, and consequently diminished microbial activity. This model assumes that polyphenols are microbially unavailable under anoxia, a supposition that has not been thoroughly investigated in any soil type. Here, we use anoxic soil reactors amended with and without a chemically defined polyphenol to test this hypothesis, employing metabolomics and genome-resolved metaproteomics to interrogate soil microbial polyphenol metabolism. Challenging the idea that polyphenols are not bioavailable under anoxia, we provide metabolite evidence that polyphenols are depolymerized, resulting in monomer accumulation, followed by the generation of small phenolic degradation products. Further, we show that soil microbiome function is maintained, and possibly enhanced, with polyphenol addition. In summary, this study provides chemical and enzymatic evidence that some soil microbiota can degrade polyphenols under anoxia and subvert the assumed polyphenol lock on soil microbial metabolism.


Assuntos
Bactérias/metabolismo , Biodegradação Ambiental , Compostos Orgânicos/metabolismo , Polifenóis/metabolismo , Poluentes do Solo/metabolismo , Anaerobiose , Reatores Biológicos/microbiologia , Microbiota/fisiologia , Compostos Orgânicos/química , Solo/química , Microbiologia do Solo , Áreas Alagadas
16.
Ecotoxicol Environ Saf ; 215: 112149, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33773153

RESUMO

The aim of present work was to evaluate the effects of titanium dioxide nanoparticles (TiO2 NPs) on rice's growth (Oryza sativa L.) and nutrient availability under different soil textures. Greenhouse experiment was carried out with three soil textures (sandy loam, silt loam and silty clay loam) and two concentrations of TiO2 NPs (500, 750 mg kg-1). Control (without TiO2 NPs) was also maintained for the comparison. Growth parameters including chlorophyll content, root/shoot length, fresh/dry biomass and nutrients' uptake including calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), phosphorous (P), potassium (K) and zinc (Zn) were determined. The results revealed that application of 500 mg kg-1 TiO2 NPs in silty clay loam soil increased the chlorophyll content (3.3-folds), root length (49%), shoot length (31%), root and shoot biomass (41% & 39%, respectively) as compared to other soil textures. The maximum plant growth was observed in silty clay loam > silt loam > sandy loam. Concentration of Cu, Fe, P and Zn in shoot was increased by 8 - , 2.3 - , 0.4 - , 0.05 -folds in silty clay loam upon 500 mg kg-1 TiO2 NPs application as compared to the control. Backward selection method to model the parameters (nutrients in soil) for the response variables (root/shoot length and biomass) showed that Ca, Fe, P are the main nutrients responsible for the increase in plant length and biomass. Overall, the growth of rice was better in silty clay loam at 500 mg kg-1 of TiO2 NPs.


Assuntos
Oryza/fisiologia , Poluentes do Solo/metabolismo , Transporte Biológico , Biomassa , Argila , Nanopartículas , Compostos Orgânicos , Oryza/crescimento & desenvolvimento , Fósforo , Desenvolvimento Vegetal , Solo , Poluentes do Solo/análise , Titânio
17.
Ecotoxicol Environ Saf ; 215: 112139, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33761378

RESUMO

Cadmium (Cd) accumulation in arable lands has become a serious matter for food security. Among various approaches, the application of nanoparticles (NPs) for remediation of contaminated water and soils is attaining more popularity worldwide. The current field experiment was executed to explore the impacts of single and combined use of ZnO NPs, Fe NPs and Si NPs on wheat growth and Cd intake by plants in a Cd-contaminated field. Wheat was sown in a field which was contaminated with Cd and was irrigated with the raw-city-effluent while NPs were applied as foliar spray alone and in all possible combinations. The data revealed that straw and grain yields were enhanced in the presence of NPs over control. Chlorophyll, carotenoids contents and antioxidants activities were enhanced while electrolyte leakage was reduced with all NPs over control. In comparison with control, Cd uptake in wheat straw was reduced by 84% and Cd uptake in grain was reduced by 99% in T8 where all three NPs were foliar-applied simultaneously. Zinc (Zn) and iron (Fe) contents were increased in those plants where ZnO and Fe NPs were exogenously applied which revealed that ZnO and Fe NPs enhanced the bio-fortification of Zn and Fe in wheat grains. Overall, foliar application of different NPs is beneficial for better wheat growth, yield, nutrients uptake and to lessen the Cd intake by plants grown in Cd-contaminated soil under real field conditions.


Assuntos
Cádmio/metabolismo , Nanopartículas/química , Poluentes do Solo/metabolismo , Triticum/fisiologia , Antioxidantes , Cádmio/análise , Cádmio/toxicidade , Clorofila , Grão Comestível/química , Poluição Ambiental , Folhas de Planta/química , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Triticum/crescimento & desenvolvimento , Zinco/análise , Óxido de Zinco
18.
Ecotoxicol Environ Saf ; 215: 112170, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33773154

RESUMO

Nanoscale zero-valent iron (nZVI) shows an excellent degradation effect on chlorinated contaminants in soil, but poses a threat to plants in combination with phytoremediation. Arbuscular mycorrhizal (AM) fungus can reduce the phyototoxicity of nZVI, but their combined impacts on polychlorinated biphenyls (PCBs) degradation and plant growth remain unclear. Here, a greenhouse pot experiment was conducted to investigate the influences of nZVI and/or Funneliformis caledonium on soil PCB degradation and ryegrass (Lolium perenne L.) antioxidative responses. The amendment of nZVI significantly reduced not only the total and homolog concentrations of PCBs in the soil, but also the ryegrass biomass as well as soil available P and root P concentrations. Moreover, nZVI significantly decreased leaf superoxide disutase (SOD) activity, while tended to decrease the protein content. In contrast, the additional inoculation of F. caledonium significantly increased leaf SOD activity and protein content, while tended to increase the catalase activity and tended to decrease the malondialdehyde content. The additional inoculation of F. caledonium also significantly increased soil alkaline phosphatase activity, and tended to increase root P concentration, but had no significantly effects on soil available P concentration, the biomass and P acquisition of ryegrass, which could be attributed to the fixation of soil available nutrients by nZVI. Additionally, F. caledonium facilitated PCB degradation in the nZVI-applied soil. Thus, AM fungus can alleviate the nZVI-induced phytotoxicity, showing great application potentials in accompany with nZVI for soil remediation.


Assuntos
Lolium/fisiologia , Bifenilos Policlorados/metabolismo , Poluentes do Solo/metabolismo , Biodegradação Ambiental , Biomassa , Fungos , Glomeromycota/fisiologia , Ferro/metabolismo , Lolium/metabolismo , Lolium/microbiologia , Micorrizas/fisiologia , Bifenilos Policlorados/análise , Solo , Microbiologia do Solo , Poluentes do Solo/análise
19.
Ecotoxicol Environ Saf ; 214: 112119, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33714137

RESUMO

Rice cultivation under cadmium (Cd) contaminated soil often results in reduced growth with excess grain Cd concentrations. A pot experiment was conducted to assess the potential of ultrasonic seed treatment to alleviate Cd stress in rice. Seeds of two aromatic rice cultivars i.e., Xiangyaxiangzhan and Meixiangzhan 2 and two non-aromatic rice cultivars i.e., Huahang 31 and Guangyan 1 were exposed to ultrasonic waves for 1.5 min in 20-40 KHz mixing frequency. The experimental treatments were comprised of untreated seeds (U0) and ultrasonic treated seeds (U1) transplanted in un-contaminated soil (H0) and Cd-contaminated soil (H1). Results revealed that Cd contents and Cd accumulation in grain in U1 were 33.33-42.31% and 12.86-57.58% lower than U0 for fragrant rice cultivars under H1. Meanwhile, biomass production was higher in U1 than U0 under H0 and better yield was assessed in U1 for all cultivars under H1. The activity of peroxidase (POD) in flag leaves was increased by 8.28-115.65% for all cultivars while malondialdehyde (MDA) contents were significantly decreased in U1 compared with U0 under H0. Conclusively, ultrasonic treatment modulated Cd distribution and accumulation in different parts while improved physiological performance as well as yield and grain quality of rice under Cd contaminated conditions.


Assuntos
Cádmio/metabolismo , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Poluentes do Solo/metabolismo , Ondas Ultrassônicas , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Malondialdeído/metabolismo , Peroxidases/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Sementes/crescimento & desenvolvimento
20.
Ecotoxicol Environ Saf ; 214: 112125, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33714138

RESUMO

Phytomanagement is proposed as a cost-effective and environmentally-friendly suggestion for sustainable use of large metal-contaminated areas. In the current work, the energy crop miscanthus (Miscanthus × giganteus) was grown in ex situ conditions on agricultural soils presenting a Cd, Pb and Zn contamination gradient. After 93 days of culture, shoot and root growth parameters were measured. Soils and plants were sampled as well to study the TE accumulation in miscanthus and the effects of this plant on TE mobility in soils. Results demonstrated that miscanthus growth depended more on the soils silt content rather than TE-contamination level. Moreover, soil organic carbon at T93 increased in the soils after miscanthus cultivation by 25.5-45.3%, whereas CaCl2-extractible TEs decreased due to complex rhizosphere processes driving plant mineral uptake, and organic carbon inputs into the rhizosphere. In the contaminated soils, miscanthus accumulated Cd, Pb and Zn mainly in roots (BCF in roots: Cd " Zn > Pb), while strongly reducing the transfer of these elements from soil to all organs and from roots to rhizomes, stems and leaves (average TFs: 0.01-0.06, 0.11-1.15 and 0.09-0.79 corresponding to Cd, Pb and Zn respectively). Therefore, miscanthus could be considered a TE-excluder, hence a potential candidate crop for coupling phytostabilization and biomass production on the studied Metaleurop TE-contaminated soils.


Assuntos
Metais Pesados/metabolismo , Poaceae/metabolismo , Poluentes do Solo/metabolismo , Biodegradação Ambiental , Biomassa , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Caules de Planta/crescimento & desenvolvimento , Caules de Planta/metabolismo , Poaceae/crescimento & desenvolvimento , Rizosfera
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