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1.
Chemosphere ; 254: 126894, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957292

RESUMO

The anthropogenic release of trifluoroacetic acid (TFA) into the environmental media is not limited to photochemical oxidation of CFC alternatives and industrial emissions. Biological degradation of some fluorochemicals is expected to be a potential TFA source. For the first time, we assess if the potential precursors [6:2 fluorotelomer alcohol (6:2 FTOH), 4:2 fluorotelomer alcohol (4:2 FTOH), acrinathrin, trifluralin, and 2-(trifluoromethyl)acrylic acid (TFMAA)] can be biologically degraded to TFA. Results show that 6:2 FTOH was terminally transformed to 5:3 polyfluorinated acid (5:3 FTCA; 12.5 mol%), perfluorohexanoic acid (PFHxA; 2.0 mol%), perfluoropentanoic acid (PFPeA; 1.6 mol%), perfluorobutyric acid (PFBA; 1.7 mol%), and TFA (2.3 mol%) by day 32 in the landfill soil microbial culture system. 4:2 FTOH could remove multiple -CF2 groups by microorganisms and produce PFPeA (2.6 mol%), PFBA (17.4 mol%), TFA (7.8 mol%). We also quantified the degradation products of TFMAA as PFBA (1.3 mol%) and TFA (6.3 mol%). Furthermore, we basically analyzed the biodegradation contribution of short-chain FTOH as raw material residuals in commercial products to the TFA burden in the environmental media. We estimate global emission of 3.9-47.3 tonnes of TFA in the period from 1961 to 2019, and project 3.8-46.4 tonnes to be emitted from 2020 to 2040 via the pathway of 4:2 and 6:2 FTOH biodegradation (0.6-7.1 and 0.6-7.0 tonnes in China, respectively). Direct evidence of the experiments indicates that biodegradation of fluorochemicals is an overlooked source of TFA and there are still some unspecified mechanisms of TFA production pathways.


Assuntos
Fluorcarbonetos/química , Microbiologia do Solo , Poluentes do Solo/análise , Ácido Trifluoracético/análise , Biodegradação Ambiental , China , Modelos Teóricos , Solo/química
2.
Chemosphere ; 254: 126904, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957297

RESUMO

Estimating bioaccessible content of mercury in soils is essential in evaluating risks that contaminated soils pose. In this study, soil samples spiked with HgCl2 through adsorption were used to test the effects of liming, soil organic matter, soil depth, and Hg concentration on the following bioaccessibility tests: dilute nitric acid at room temperature, dilute nitric acid at body temperature, Simplified Bioaccessibility Extraction Test (SBET) method, and gastric phase of the In vitro Gastrointestinal (IVG) protocol. Soil and sediment samples from Descoberto, Minas Gerais (Brazil), a city with a well-known record of Hg contamination from artisanal mining, were subjected to these bioaccessibility tests for the first time, and the different methods of estimating bioaccessible content were compared. Bioaccessible fractions in spiked samples ranged from 10% to 60%, and this high bioaccessibility was due to the highly soluble species of Hg and the short time under adsorption. In general, clay and organic matter decreased bioaccessible content. Although the soil in Descoberto is undoubtedly polluted, mercury bioaccessibility in that area is low. In general, dilute nitric acid estimated higher bioaccessible content in soil samples, whereas the SBET method estimated higher bioaccessible content in sediment samples. In multivariate analysis, two groups of bioaccessibility tests arise: one with the two nitric acid tests, and the other with SBET and the gastric phase of the IVG protocol. The addition of pepsin and glycine in the last two tests suggests a more reliable test for assessing mercury bioaccessibility.


Assuntos
Argila/química , Substâncias Húmicas/análise , Mercúrio/análise , Mineração , Poluentes do Solo/análise , Solo/química , Adsorção , Disponibilidade Biológica , Brasil , Cidades , Mucosa Gástrica/metabolismo , Humanos , Mucosa Intestinal/metabolismo , Mercúrio/metabolismo , Modelos Biológicos , Ácido Nítrico/química , Poluentes do Solo/metabolismo
3.
Chemosphere ; 254: 126909, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957299

RESUMO

Soil contamination by heavy metals (HMs) is an environmental problem, and nanoremediation by using zero-valent iron nanoparticles (nZVI) has attracted increasing interest. We used ecotoxicological test and global transcriptome analysis with DNA microarrays to assess the suitability of C. elegans as a useful bioindicator to evaluate such strategy of nanoremediation in a highly polluted soil with Pb, Cd and Zn. The HMs produced devastating effect on C. elegans. nZVI treatment reversed this deleterious effect up to day 30 after application, but the reduction in the relative toxicity of HMs was lower at day 120. We stablished gene expression profile in C. elegans exposed to the polluted soil, treated and untreated with nZVI. The percentage of differentially expressed genes after treatment decreases with exposure time. After application of nZVI we found decreased toxicity, but increased biosynthesis of defensive enzymes responsive to oxidative stress. At day 14, when a decrease in toxicity has occurred, genes related to specific heavy metal detoxification mechanisms or to response to metal stress, were down regulated: gst-genes, encoding for glutathione-S-transferase, htm-1 (heavy metal tolerance factor), and pgp-5 and pgp-7, related to stress response to metals. At day 120, we found increased HMs toxicity compared to day 14, whereas the transcriptional oxidative and metal-induced responses were attenuated. These findings indicate that the profiled gene expression in C. elegans may be considered as an indicator of stress response that allows a reliable evaluation of the nanoremediation strategy.


Assuntos
Caenorhabditis elegans/efeitos dos fármacos , Ferro/química , Metais Pesados/toxicidade , Nanopartículas/química , Estresse Oxidativo/efeitos dos fármacos , Poluentes do Solo/toxicidade , Transcrição Genética/efeitos dos fármacos , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Ecotoxicologia , Nanopartículas Metálicas , Metais Pesados/análise , Estresse Oxidativo/genética , Solo/química , Microbiologia do Solo , Poluentes do Solo/análise , Toxicogenética
4.
Ecotoxicol Environ Saf ; 203: 111023, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888592

RESUMO

Tembotrione is a triketone group herbicide having worldwide applications for weed management in maize. It is considered to be less stable in the environment and its degradation products may have toxicological consequences due to longer persistence and off-site movements. We studied the persistence behavior and leaching potential of tembotrione and its major metabolite TCMBA in clay loam and sandy loam soils having different physico-chemical properties. The rapid transformation of parent tembotrione to degradation products and their high interactions with soil provided challenging task of residues separation from complex soil matrix. Therefore, a novel sample preparation method (modified QuEChERS) was optimized for trace estimation of tembotrione and TCMBA which offered 86.6-95.6% recoveries with limit of detection (LOD) and quantification (LOQ) as 0.001 and 0.003 µg/g, respectively in both soils without any matrix interference. A first order dissipation kinetics was followed by tembotrione and TCMBA residues with half-life ranged from 7.2 to 13.4 days in both soils. Residues reached below detectable limit on 45-60 days after treatments in two application doses. Leaching experiment revealed maximum retention of tembotrione residues from 15 to 25 cm depth in both soils whereas TCMBA show appreciable leaching potential. It was concluded that tembotrione can be phytotoxic to the succeeding crops if applied at late post-emergence stage. TCMBA can contaminate surface and ground water due to continuous and prolonged use of tembotrione particularly in light textured soils.


Assuntos
Benzoatos/análise , Cicloexanonas/análise , Herbicidas/análise , Resíduos de Praguicidas/análise , Poluentes do Solo/análise , Solo/química , Sulfonas/análise , Argila/química , Produtos Agrícolas/crescimento & desenvolvimento , Cinética , Limite de Detecção , Zea mays/crescimento & desenvolvimento
5.
Ecotoxicol Environ Saf ; 205: 111347, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32961489

RESUMO

The soil cadmium (Cd) contamination is a ubiquitous environmental problem that has resulted from intense irrigation with wastewater. This pot trial was conducted with aim to produce safe food with Cd tolerant wheat cultivar in wastewater irrigated soils. For this purpose, two wheat cultivars NARC-2011 (Cd tolerant) and Shafaq-2006 (Cd sensitive) were screened out and selected, after conducting a pilot trial of twelve local wheat cultivars against Cd stress. Both cultivars were grown in naturally contaminated soils with Cd concentrations (4.18, 3.23, 2.29 and 1.25 mg kg-1). After harvesting, NARC-2011 showed significant photosynthetic attributes, grain biochemical parameters and yield. Additionally, Cd concentrations in edible grains of NARC-2011 cultivars were found within standard limits (200 mg kg-1), in all contaminated soils. Furthermore, a marked decrease in Cd bioavailability was noted with cultivar NARC-2011, where contribution of mobile Cd fractions (exchangeable and reducible) percentage was decreased, while immobile Cd fractions percentage increased (oxidizable and residual). Fourier transform infrared (FTIR) spectroscopy reflects the maturity and stability of humic and fulvic like acid fractions and revealed that humification of these compounds after prolonged sludge enriched wastewater irrigation lowered the Cd availability. The wheat cultivar NARC-2011 (Cd tolerant) could be opted to grow on soils irrigated with wastewater for a long time, as Cd bioavailability decreased with ageing due to stabilized humic substances and varietal tolerance.


Assuntos
Irrigação Agrícola , Cádmio/análise , Poluentes do Solo/análise , Triticum/química , Benzopiranos , Disponibilidade Biológica , Grão Comestível/química , Substâncias Húmicas/análise , Esgotos/análise , Solo/química , Eliminação de Resíduos Líquidos , Águas Residuárias/química
6.
Ecotoxicol Environ Saf ; 205: 111324, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32971453

RESUMO

Chlorantraniliprole (CAP) is extensively used for rice pest management. Lack of information on the role of standing water and amount and timing of rainfall on CAP dissipation in rice ecosystem could hamper its prospective use. Present study was performed to investigate the effects of different water regimes (saturated, 5 and 10 cm standing water) and simulated rainfall (40 and 100 mm occurred at 4, 8 and 24 h after CAP application) on leaching, surface runoff and dissipation of CAP into components of rice ecosystem. The results showed highest concentration of CAP residues in soil and plant under saturated condition followed by 5 and 10 cm standing water conditions. Whereas, the highest concentration of CAP in leachates was detected under 10 cm standing water (12.19 ng mL-1). The results revealed large amount of leaching (21.99 ng mL-1) and surface runoff (42.25 ng mL-1) losses of CAP when 100 mm rainfall occurred at 4 h after pesticide application. The total quantity of CAP residues in soil and plant was highest when rainfall occurred at 24 h after pesticide application under both the rainfall amounts. Water stagnation and high intensity rainfall occurred shortly after pesticide application will contribute to pesticide loss to non-target sites through surface run-off and leaching. There will be less pesticide available in soil for plant uptake which may not be sufficient to kill the target organisms.


Assuntos
Mudança Climática , Ecossistema , Inseticidas/análise , Oryza , Chuva , ortoaminobenzoatos/análise , Praguicidas/análise , Estudos Prospectivos , Solo/química , Poluentes do Solo/análise , Água/química , Poluentes Químicos da Água/análise
7.
Ecotoxicol Environ Saf ; 205: 111374, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32977284

RESUMO

Phenazines, a large group of nitrogen-containing heterocycles with promising bioactivities, can be widely used as medicines and pesticides. But phenazines also generate toxicity risks due to their non-selective DNA binding. The environmental fate of phenazines in soils is the key to assess their risks; however, hitherto, there have been very few related studies. Therefore in the present study, the degradation, adsorption and leaching behaviors of a typical natural phenazine-phenazine-1-carboxamide (PCN) in agricultural soils from three representative places in China with different physicochemical properties were, for the first time, systematically studied in laboratory simulation experiments. Our results indicated that the degradation of PCN in all the tested soils followed the first order kinetics, with half-lives ranging from 14.4 to 57.8 d under different conditions. Soil anaerobic microorganisms, organic matter content and pH conditions are important factors that regulating PCN degradation. The adsorption data of PCN were found to be well fitted using the Freundlich model, with the r2 values above 0.978. Freundlich adsorption coefficient Kf of PCN ranged from 5.75 to 12.8 [(mg/kg)/(mg/L)1/n] in soils. The retention factor Rf values ranged from 0.0833 to 0.354, which means that the mobility of PCN in the three types of soil is between immobile to moderately mobile. Our results demonstrate that PCN is easily degraded, has high adsorption affinity and low mobility in high organic matter content and clay soils, thus resulting in lower risks of contamination to groundwater systems. In contrast, it degraded slowly, has low adsorption affinity and moderately mobile in soils with low organic matter and clay content, therefore it has higher polluting potential to groundwater systems. Overall, these findings provide useful insights into the future evaluation of environmental as well as health risks of PCN.


Assuntos
Fenazinas/análise , Poluentes do Solo/análise , Adsorção , Agricultura , China , Argila , Água Subterrânea , Cinética , Praguicidas , Solo/química
8.
Ecotoxicol Environ Saf ; 205: 111321, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32979800

RESUMO

Soil pollution with cadmium (Cd) has posed a threat to our food safety. And rice consumption is the main source of Cd intake in China. Rice intercropping with water spinach is an efficient way for crop production and phytoremediation in Cd-contaminated soil. However, few people work on the Cd remediation by a combination of the passivation and intercropping. In this study, two passivators (the Si-Ca-Mg ameliorant and the Fe-modified biochar with microbial inoculants) were used in the monoculture and intercropping systems to evaluate the potential of co-effect of passivators and cropping systems on the plant growth and Cd phytoremediation. Results showed that the highest rice biomass and rice yield were presented in the intercropping system with the passivator additions, however, relatively lower biomass was showed in water spinach due to the competition with rice. And more Cd accumulated in water spinach while lower Cd in that of different rice parts. The intercropping system with the addition of the Si-Ca-Mg ameliorant and the microbial Fe-modified biochar significantly reduced the Cd contents in brown rice by 58.86% and 63.83%, while notably enhanced the Cd accumulation of water spinach by 32.0% and 22.0%, compared with the monoculture without passivation, respectively. This probably due to the increased pH, the lowered Cd availability in soil, and the reduced TF and BCF values in rice plants with passivator applications. Collectively, this study indicated that rice-water spinach intercropping, especially with the passivator additions, may function as an effective way for Cd remediation and guarantee rice grain safety.


Assuntos
Biodegradação Ambiental , Cádmio/análise , Oryza/fisiologia , Spinacia oleracea/fisiologia , Biomassa , Carvão Vegetal , China , Grão Comestível/química , Ipomoea , Oryza/crescimento & desenvolvimento , Solo/química , Poluentes do Solo/análise , Água
9.
Ecotoxicol Environ Saf ; 203: 111047, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888598

RESUMO

Understanding azo dye degrading enzymes and the encoding of their functional genes is crucial for the elucidation of their molecular mechanisms. In this study, a thermophilic strain capable of degrading azo dye was isolated from the soil near a textile dye manufacturing factory. Based on its morphological, physiological and biochemical properties, as well as 16S rRNA gene sequence analysis, the strain was identified as Anoxybacillus sp. PDR2. The decolorization ratios of 100-600 mg/L Direct Black G (DBG) by strain PDR2 reached 82.12-98.39% within 48 h of dyes. Genome analysis revealed that strain PDR2 contains a circular chromosome of 3791144 bp with a G + C content of 42.48%. The genetic basis of azo dye degradation by strain PDR2 and its capacity to adapt to harsh environments, were further elucidated through bioinformatics analysis. RNA-Seq and qRT-PCR technology confirmed that NAD(P)H-flavin reductase, 2Fe-2S ferredoxin and NAD(P)-dependent ethanol dehydrogenase genes expressed by strain PDR2, were the key genes involved in DBG degradation. The combination of genome and transcriptome analysis was utilized to explore the key genes of strain PDR2 involved in azo dye biodegradation, with these findings providing a valuable theoretical basis for the practical treatment of azo dye wastewater.


Assuntos
Anoxybacillus/isolamento & purificação , Compostos Azo/análise , Corantes/análise , Genes Bacterianos , Microbiologia do Solo , Anoxybacillus/genética , Anoxybacillus/metabolismo , Compostos Azo/metabolismo , Biodegradação Ambiental , China , Corantes/metabolismo , Perfilação da Expressão Gênica , Genômica , RNA Ribossômico 16S/genética , Solo/química , Indústria Têxtil
10.
Ecotoxicol Environ Saf ; 203: 111055, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888617

RESUMO

The pollution level of potentially toxic elements (PTEs) in surface soils is detrimental to the ecosystem and human health. In this research, various indices such as an index of geo-accumulation (Igeo), contamination factor (CF), degree of contamination (DC), and principal component analysis (PCA) were implemented to identify and evaluate the soil PTEs pollution; and then human health risk assessment model used to establish the link between heavy metals pollution and human health in the urban region of south India. Results exhibited that the mean concentration of Cr, Cu, Ni and Zn were found to be 1.45-6.03 times greater than the geochemical background values. Cr and Cu were the most profuse PTEs measured in the soils. The pollution indices suggest that soil of the study region is mainly moderate to highly polluted. The non-carcinogenic health risk assessment proposed by the United States Environmental Protection Agency (USEPA) suggested the mean hazard indices (HIs) were below one which denotes no significant of non-carcinogenic risks to both children and adults. Furthermore, carcinogenic risk assessment results advised ~80% of cancer risk was caused by Cr contents, while other heavy metals indicate that neither children nor adults in the study region were of carcinogenic risks.


Assuntos
Carcinógenos/análise , Monitoramento Ambiental/métodos , Substâncias Perigosas/análise , Metais Pesados/análise , Poluentes do Solo/análise , Solo/química , Adulto , Carcinógenos/toxicidade , Criança , Ecossistema , Substâncias Perigosas/toxicidade , Humanos , Índia , Metais Pesados/toxicidade , Medição de Risco , Poluentes do Solo/toxicidade , Estados Unidos , United States Environmental Protection Agency , Urbanização
11.
Nat Commun ; 11(1): 4721, 2020 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-32948775

RESUMO

The importance of soil age as an ecosystem driver across biomes remains largely unresolved. By combining a cross-biome global field survey, including data for 32 soil, plant, and microbial properties in 16 soil chronosequences, with a global meta-analysis, we show that soil age is a significant ecosystem driver, but only accounts for a relatively small proportion of the cross-biome variation in multiple ecosystem properties. Parent material, climate, vegetation and topography predict, collectively, 24 times more variation in ecosystem properties than soil age alone. Soil age is an important local-scale ecosystem driver; however, environmental context, rather than soil age, determines the rates and trajectories of ecosystem development in structure and function across biomes. Our work provides insights into the natural history of terrestrial ecosystems. We propose that, regardless of soil age, changes in the environmental context, such as those associated with global climatic and land-use changes, will have important long-term impacts on the structure and function of terrestrial ecosystems across biomes.


Assuntos
Biota , Ecossistema , Solo/química , Bactérias/classificação , Biodiversidade , Biomassa , Clima , Fungos/classificação , Microbiota , Plantas/classificação , Fatores de Tempo
12.
Bull Environ Contam Toxicol ; 105(4): 553-558, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32918155

RESUMO

The aim of this study was to evaluate, through nonlinear regression models, the initial development of soybean (Glycine max L. Merr. cv. BRS 257) in soil supplemented with different copper levels. The experiment was performed in a greenhouse under natural light and temperature conditions. The seeds were sowed in soil containing different copper levels (11.20, 32.28, 52.31, 64.51, 79.42, 117.70, 133.53, 144.32, or 164.00 mg kg- 1). Germination percentage was not affected by the increase of copper content in the soil, but there was a delay in the germination process. There was no influence of copper levels on the seedling emergence speed index until 98.42 mg kg- 1; however, higher copper amounts reduced this parameter. Low copper concentrations increased plant development, but higher concentrations compromised mainly root growth. Overall, these results suggest that copper supplementation in the soil exerted dose-dependent dual effects on soybean seedlings.


Assuntos
Cobre/efeitos adversos , Germinação/efeitos dos fármacos , Poluentes do Solo/efeitos adversos , Soja/efeitos dos fármacos , Relação Dose-Resposta a Droga , Dinâmica não Linear , Análise de Regressão , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Solo/química , Soja/crescimento & desenvolvimento
13.
Bull Environ Contam Toxicol ; 105(4): 572-581, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32960333

RESUMO

In order to assess the environmental impacts caused by flood to the paddy field, 940 semi-volatile organic compounds (SVOCs) were screened in paddy soil samples taken in central Vietnam before and after flooding. The concentration of 166 SVOCs in soil samples ranged from 0.031 to 2241 (mean 89.1) µg kg-1 dry wt. Chemicals originating from household sources showed the highest level, followed by chemicals originating from agriculture. Since untreated domestic wastewater used for agricultural irrigation, organic micro-pollutants in domestic wastewater is the main source of pollutants in paddy soil. However, contamination levels of pollutants in paddy soil after flooding were lower than those before flooding, possibly due to the removal of pollutants by floodwater. As a result, pollution characteristic of pollutants at sampling locations were different before flooding while they became similar after flooding due to the dispersion and elution of organic pollutants from soil into floodwaters.


Assuntos
Monitoramento Ambiental , Inundações , Compostos Orgânicos/análise , Poluentes do Solo/análise , Poluentes Químicos da Água/análise , Oryza/crescimento & desenvolvimento , Solo/química , Vietnã
14.
Bull Environ Contam Toxicol ; 105(4): 559-564, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32974765

RESUMO

In this work, we propose to evaluate the effect of agriculture intensification under greenhouses on the biochemical and transcriptomic responses of the earthworms Eisenia andrei. This work was conducted on two sites in Téboulba and Sahline (Monastir governorate) and a control site in an experimental plot that is undergoing organic farming. For this purpose, the earthworms Eisenia andrei were exposed to the soils during 7 and 14 days. The physicochemical properties of the soils were analyzed. The biochemical biomarkers of metallothioneins (MTs) and malondialdehyde (MDA) accumulations were also assessed. Moreover, the gene expression level of the MTs was analyzed. The results of our study revealed a significant trace element accumulation accompanied by a high level of MDA and MT proteins. Moreover, a significant expression of the MT gene was observed in earthworms exposed to the soils from Sahline and Téboulba. Hence, this work reveals that intensive agriculture can affect the biological responses of earthworms and consequently, the soil's biofertility.


Assuntos
Agricultura , Biomarcadores Ambientais/fisiologia , Metais Pesados/metabolismo , Oligoquetos/efeitos dos fármacos , Poluentes do Solo/metabolismo , Solo/química , Agricultura/métodos , Animais , Expressão Gênica/efeitos dos fármacos , Malondialdeído/metabolismo , Metalotioneína/metabolismo , Oligoquetos/genética , Oligoquetos/metabolismo , Tunísia
15.
Ecotoxicol Environ Saf ; 203: 111007, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888586

RESUMO

Soil acidification is one of the crucial global environmental problems, affecting sustainable land use, crop yield, and ecosystem stability. Previous research reported the tolerance of crops to acid soil stress. However, the molecular response of woody plant to acid conditions remains largely unclear. Rhododendron L. is a widely distributed woody plant genus and prefers to grow in acidic soils. Herein, weighted gene coexpression network analysis was performed on R. protistum var. giganteum seedlings subjected to five pH treatments (3.5, 4.5, 5.5, 6.0, 7.0), and their ecophysiological characteristics were determined for the identification of their molecular responses to acidic environments. Through pairwise comparison, 855 differentially expressed genes (DEGs) associated with photosynthesis, cell wall, and phenylpropanoid metabolism were identified. Most of the DEGs related to photosynthesis and cell wall were up-regulated after pH 4.5 treatment. Results implied that the species improves its photosynthetic abilities and changes its cell wall characteristics to adapt to acidic conditions. Weighted gene co-expression network analyses showed that most of the hub genes were annotated to the biosynthetic pathways of ribosomal proteins and photosynthesis. Expression pattern analysis showed that genes encoding subunit ribosomal proteins decreased at pH 7.0 treatment, suggesting that pH 7.0 treatment led to cell injury in the seedlings. The species regulates protein synthesis in response to high pH stress (pH 7.0). The present study revealed the molecular response mechanism of woody plant R. protistum var. giganteum to acid environments. These findings can be useful in enriching current knowledge of how woody species adapt to soil acidification under global environmental changes.


Assuntos
Ácidos/farmacologia , Parede Celular/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Madeira/efeitos dos fármacos , Parede Celular/genética , Parede Celular/metabolismo , Perfilação da Expressão Gênica , Redes Reguladoras de Genes/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Fotossíntese/genética , Plântula/efeitos dos fármacos , Plântula/metabolismo , Solo/química , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genética , Madeira/genética , Madeira/metabolismo
16.
Ecotoxicol Environ Saf ; 203: 111010, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888587

RESUMO

Manganese (Mn) toxicity is common in plants grown on very acid soils. However, some plants species that grow in this condition can take up high amounts of Mn and are referred to as hyperaccumulating species. In this study, we evaluated the capacity of Ilex paraguariensis to accumulate Mn and the effect of excessive concentrations on plant growth and nutrition. For this, a container experiment was conducted using soils from different parent materials (basalt and sandstone), with and without liming, and at six doses of applied Mn (0, 30, 90, 270, 540 and 1,080 mg kg-1). Clonal plants grown for 203 days were harvested to evaluate yield, and leaf tissue samples were evaluated for Mn and other elements. Without liming and with high Mn doses, leaf Mn concentrations reached 13,452 and 12,127 mg kg-1 in sandstone and basalt soils, respectively; concentrations in excess of 10,000 mg kg-1 are characteristic of hyperaccumulating plants. Liming reduced these values to 7203 and 8030 mg kg-1. More plant growth accompanied increased Mn leaf concentrations, with a growth reduction noted at the highest dose in unlimed soils. Elemental distribution showed Mn presence in the mesophyll, primarily in vascular bundles, without high Mn precipitates. Interveinal chlorosis of young leaves associated with high Mn concentration and lower Fe concentrations was observed, especially in sandstone soil without liming. However, the occurrence of this symptom was not associated with decreased plant growth.


Assuntos
Ácidos/farmacologia , Ilex paraguariensis/metabolismo , Manganês/metabolismo , Doenças das Plantas/induzido quimicamente , Poluentes do Solo/metabolismo , Ácidos/análise , Compostos de Cálcio/análise , Compostos de Cálcio/farmacologia , Ilex paraguariensis/efeitos dos fármacos , Ilex paraguariensis/crescimento & desenvolvimento , Ferro/metabolismo , Manganês/análise , Manganês/toxicidade , Óxidos/análise , Óxidos/farmacologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Solo/química , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
17.
Ecotoxicol Environ Saf ; 203: 110990, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888601

RESUMO

The presence of sulfamethoxazole (SMX) in croplands has become an international concern. The environmental behavior and fate of SMX in agricultural soils are not well understood, especially when the adsorption behavior is disturbed by the dissolved organic matter (DOM) released by crop straw. As canola straw is one of the biomasses widely returned to farmlands, we characterized DOM derived from pristine and decomposed canola straw, and explored the effects and mechanisms of the DOMs on regulating SMX adsorption to purple paddy soils. The spectral analysis showed that the molecular weight, aromaticity, and hydrophobicity of canola straw-derived DOM increased as decomposition proceeded. These physicochemical properties collectively determined the effects of the DOM on SMX adsorption. The DOM derived from pristine canola straw increased SMX maximum adsorption capacity of the soils by approximately 2.6 times, but this positive effect gradually decreased to a steady state by day 90 in the straw decomposition period. Nevertheless, the SMX adsorption behavior in the soils was invariably determined by the DOM extracts. These adsorption processes of SMX were well fitted by the double-chamber kinetics model and the Langmuir and Freundlich thermodynamic models. Thermodynamic parameters indicated that SMX adsorption onto the soils was spontaneous and endothermic, and this adsorption characteristics was not significantly (p > 0.05) changed by the DOM extracts. However, the adsorption kinetics were altered by those DOMs, i.e., the fast and slow adsorption processes were both diminished. Correspondingly, co-adsorption and cumulative adsorption were identified as the main mechanisms determining SMX adsorption to the purple paddy soils in the presence of the straw-derived DOMs. These results collectively indicated that the DOMs released by straw in croplands may decrease the ecological risks of organic pollutants by inhibiting their migration processes.


Assuntos
Brassica/química , Poluentes do Solo/química , Solo/química , Sulfametoxazol/química , Adsorção , Agricultura , Oryza/crescimento & desenvolvimento , Silagem
18.
Bull Environ Contam Toxicol ; 105(4): 633-638, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32960332

RESUMO

Waste disposal, metal plating, refineries, and mining operations frequently contaminate soils with nickel (Ni). We explored the effects of artificial Ni contamination (0, 56, and 180 mg Ni kg-1) on the soil biochemical indices. The lab experiment also investigated the possible use of kunai grass (Imperata cylindrica) biochar at a 0.75% dry weight basis to alleviate contamination effects. The biochemical indices such as dehydrogenase enzyme activity, acid phosphatase enzyme activity, and soil respiration rates were monitored in three replications. High level of Ni (180 mg kg-1) suppressed soil respiration rate by 37% and dehydrogenase activity by 62% up to 15 days. The acid phosphatase activity was not affected by Ni levels and was insensitive to Ni contamination. Biochar application to the Ni contaminated soil did not improve the soil's key biological properties. The beneficial effects of biochar could be limited to improvements in soil chemical properties and not on index biological properties.


Assuntos
Níquel/análise , Poluentes do Solo/análise , Carvão Vegetal , Mineração , Poaceae , Solo/química
19.
Bull Environ Contam Toxicol ; 105(4): 602-606, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32978647

RESUMO

A method for simultaneous quantitation of rimsulfuron, quizalofop-P-ethyl and quizalofop-P in potato plant, soil and potato tuber samples was established. The mean recoveries of rimsulfuron, quizalofop-P-ethyl and quizalofop-P in different matrices spiked with them were 81.4%-101.1%, 76.1%-99.0% and 77.4%-106.4% with relative standard deviations (RSDs) of 2.7%-13.3%, 0.9%-5.5%, 1.7%-11.3%, respectively. The open-field trials in China were conducted in potato cultivation system of Changchun and Jinan. The results indicated that the half-lives of rimsulfuron and quizalofop-P-ethyl were 0.04-13.1 days. The residues of quizalofop-P during the harvest time in Jinan soil were < 0.01-0.044 mg kg-1, while there was no residue of target herbicides detected in all other samples. The risk assessment results demonstrated that the risk quotients (RQs) of rimsulfuron and quizalofop-P-ethyl were 7.857 × 10-5 and 8.730 × 10-3, respectively, which exhibited an acceptable dietary risk to Chinese consumers.


Assuntos
Resíduos de Praguicidas/análise , Propionatos/análise , Piridinas/análise , Quinoxalinas/análise , Poluentes do Solo/análise , Sulfonamidas/análise , China , Herbicidas/análise , Medição de Risco , Solo/química , Solanum tuberosum
20.
Nat Commun ; 11(1): 4897, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32994415

RESUMO

Soil microbial respiration is an important source of uncertainty in projecting future climate and carbon (C) cycle feedbacks. However, its feedbacks to climate warming and underlying microbial mechanisms are still poorly understood. Here we show that the temperature sensitivity of soil microbial respiration (Q10) in a temperate grassland ecosystem persistently decreases by 12.0 ± 3.7% across 7 years of warming. Also, the shifts of microbial communities play critical roles in regulating thermal adaptation of soil respiration. Incorporating microbial functional gene abundance data into a microbially-enabled ecosystem model significantly improves the modeling performance of soil microbial respiration by 5-19%, and reduces model parametric uncertainty by 55-71%. In addition, modeling analyses show that the microbial thermal adaptation can lead to considerably less heterotrophic respiration (11.6 ± 7.5%), and hence less soil C loss. If such microbially mediated dampening effects occur generally across different spatial and temporal scales, the potential positive feedback of soil microbial respiration in response to climate warming may be less than previously predicted.


Assuntos
Carbono/análise , Metagenoma/genética , Microbiota/fisiologia , Microbiologia do Solo , Solo/química , Aclimatação/genética , Archaea/genética , Archaea/isolamento & purificação , Archaea/metabolismo , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Carbono/metabolismo , Ciclo do Carbono , Celulose/metabolismo , DNA Ambiental/genética , DNA Ambiental/isolamento & purificação , Fungos/genética , Fungos/isolamento & purificação , Fungos/metabolismo , Aquecimento Global , Pradaria , Temperatura Alta/efeitos adversos , Metagenômica , Modelos Genéticos , Raízes de Plantas/química , Poaceae/química
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