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1.
Bioresour Technol ; 295: 122197, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31630888

RESUMO

In this article, the changes in the functional marker genes associated with nitrogen biological transformation during the organic-inorganic co-composting process with adding biochar or not were studied. Results showed that the addition of biochar increased the abundance of ureC, AOA amoA and AOB amoA gene while decreased the abundance of nirK gene. The addition of 10% biochar by weight ratio was better for the optimization of nitrogen biological transformation process. The correlation analysis showed that the ureC gene was highly correlated with NH4+-N concentration while the AOA amoA and AOB amoA genes were moderately correlated with NH4+-N concentration. Similarly, the nirK gene was moderately correlated with NO3--N concentration. This work would contribute to understanding the mechanisms underlying in the nitrogen bio-transformation further at the molecular level during organic-inorganic co-composting.


Assuntos
Compostagem , Amônia , Archaea , Nitrogênio , Ciclo do Nitrogênio , Solo , Microbiologia do Solo
2.
Bioresour Technol ; 295: 122267, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31648128

RESUMO

Metagenomic and transcriptomic techniques applied to composting could increase our understanding of the overall microbial ecology and could help us to optimise operational conditions which are directly related with economic interest. In this study, the fungal diversity and abundance of two-phase olive mill waste ("alperujo") composting was studied using Illumina MiSeq sequencing and quantitative PCR, respectively. The results showed an increase of the fungal diversity during the process, with Ascomycota being the predominant phylum. Penicillium was the main genera identified at the mesophilic and maturation phases, with Debaryomyces and Sarocladium at the thermophilic phase, respectively. The fungal abundance was increased during composting, which confirms their important role during thermophilic and maturation phases. Some Basidiomycota showed an increased during the process, which showed a positive correlation with the humification parameters. According to that, the genus Cystofilobasidium could be used as a potential fungal biomarker to assess alperujo compost maturation.


Assuntos
Ascomicetos , Basidiomycota , Compostagem , Olea , Solo
3.
Waste Manag ; 101: 74-82, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31604160

RESUMO

Biosolarization utilizes organic amendments to produce biopesticide compounds in soil that can work in tandem with other stresses to inactivate agricultural pests. The prospect of using by-products from industrial almond processing as amendments for biosolarization was assessed. Soil mesocosms were used to simulate biosolarization using various almond by-products, application rates, and incubation times. Several potentially biopesticidal organic acids were identified and quantified in the soil, and the toxicity of soil extracts was evaluated for the root lesion nematode (Pratylenchus vulnus). It was determined that both almond hulls and a mixture of hulls and shells harbored several acids, the concentration of which was enhanced 1-7 fold via fermentation by native soil microbes. Organic acid concentration in the soil showed a significant linear relationship with the quantity of waste biomass amended. Extracts from soils containing at least 2.5% incorporated biomass by dry weight showed a 84-100% mortality of nematodes, which corresponded to acid concentrations 0.75 mg/g (2.0 g/L) or greater. This study showed that almond processing by-products - hulls and a hull and shell mixture - were suitable amendments for control of P. vulnus and potentially other soil agricultural pests in the context of biosolarization.


Assuntos
Agentes de Controle Biológico , Prunus dulcis , Agricultura , Biomassa , Solo
4.
Waste Manag ; 101: 94-105, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31606613

RESUMO

The re-use of waste materials by application to land is an increasingly common practice around the world, but where municipal solid waste materials are applied, it is almost inevitable that physical contaminants such as glass and plastic will be added to the soil. In many jurisdictions, there are prescribed limits for the amounts of physical contaminants that may be present in these materials, but there is little information on whether these limits safeguard soil functional condition. Here, physical contamination of soil is described after varying rates of a mixed waste organic output (MWOO) and garden waste compost (GWC) were incorporated into field plots. At application rates of 100 and 200 t/ha, both treatments resulted in a coarsening of the topsoil particle size distribution, but only in the MWOO-treated soils were physical contaminants largely responsible for this. The physical contaminant particles present were found only to the depth of cultivation, and included glass, rigid and film plastics, and synthetic fibres. These contaminants were most commonly observed in the gravel and coarse sand-sized fractions, and in those soils treated with the highest rates of MWOO application. Physical contaminant particles acted as both enveloping and nucleating agents for mineral grains and organic matter, and blocked some pores. Although soil physical condition is usually improved by the incorporation of organic matter, the extent of pore blockage evident here suggests that soil physical functions such as water percolation may be affected as the organic matter is broken down and the soil undergoes natural re-consolidation.


Assuntos
Compostagem , Poluentes do Solo , Jardins , Solo , Resíduos Sólidos
5.
Waste Manag ; 101: 126-140, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31610474

RESUMO

The increasing use of forest biomass as a fuel for power plants due to environmental concerns will certainly increase the amount of woody biomass ash produced. Because of the environmental problems derived from woody biomass ash disposal, an important aspect for the sustainable development of the energy sector is the implementation of effective ash management strategies. The purpose of this study is to assess the environmental impacts of woody biomass ash landfarming for soil amelioration through a Life Cycle Assessment. The baseline scenario corresponds to the current most common practice of woody biomass ash management (landfilling), and two different landfarming alternatives were assessed: liming and fertilisation. Credits were given to the system due to the substitution of three traditional liming products and five traditional fertilisers. Woody biomass ash landfarming presented satisfactory performance in five impact categories under study in comparison to landfilling. When woody biomass ash was used for liming, the environmental savings were more pronounced when substituting hydrated lime. For potassium supply, the substitution of potassium nitrate by woody biomass ash presented the best environmental performance, while for phosphorus supply, the environmental savings were more pronounced substituting single superphosphate. However, in four impact categories, the environmental impacts of ash landfarming exceeded the impacts of ash landfilling, due to the emission to soil of nutrients and trace elements to soil. But this does not necessarily imply increased risks for the environment, as the potential pollutants leaching depends on their bioavailability in the soil.


Assuntos
Poluentes do Solo , Oligoelementos , Biomassa , Cinza de Carvão , Fertilizantes , Florestas , Solo
6.
Bioresour Technol ; 295: 122175, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31570260

RESUMO

The aim of this study is to reduce nitrogen (N) loss and investigate the role of ammonia (NH3) recycling on N fractions, environmental factors and bacterial communities. In this study, collected NH3 from composting and recycled in it. The results showed that NH3 recycling affected N-cycling processes such as nitrification. Redundancy Analyses (RDA) showed that NH4+-N had significantly negative correlation with denitrifying bacteria in treatment group (p < 0.05), demonstrating that NH3 recycling have influenced on the bacterial community structure. Furthermore, Structural Equation Model (SEM) revealed causal relationships between visual variables. Based on these results, we concluded that NH3 recycling is a novel method to reduce N loss.


Assuntos
Compostagem , Amônia , Nitrogênio , Esgotos , Solo
7.
Rev Environ Contam Toxicol ; 252: 51-96, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31286265

RESUMO

In the past two decades, increased production and usage of metallic nanoparticles (NPs) have inevitably increased their discharge into the different compartments of the environment, which ultimately paved the way for their uptake and accumulation in various trophic levels of the food chain. Due to these issues, several questions have been raised on the usage of NPs in everyday life and have become a matter of public health concern. Among the metallic NPs, Cu-based NPs have gained popularity due to their cost-effectiveness and multifarious promising uses. Several studies in the past represented the phytotoxicity of Cu-based NPs on plants. However, comprehensive knowledge is still lacking. Additionally, the impact of Cu-based NPs on soil organisms such as agriculturally important microbes, fungi, mycorrhiza, nematode, and earthworms is poorly studied. This review article critically analyses the literature data to achieve a more comprehensive knowledge on the toxicological profile of Cu-based NPs and increase our understanding of the effects of Cu-based NPs on aquatic and terrestrial plants as well as on soil microbial communities. The underlying mechanism of biotransformation of Cu-based NPs and the process of their penetration into plants have also been discussed herein. Overall, this review could provide valuable information to design rules and regulations for the safe disposal of Cu-based NPs into a sustainable environment.


Assuntos
Cobre , Poluentes Ambientais , Nanopartículas Metálicas , Animais , Cadeia Alimentar , Oligoquetos , Solo
8.
Water Res ; 168: 115182, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31634706

RESUMO

Low-molecular-weight organic acids (LMWOAs) are ubiquitous in the aquatic environment and consequently may affect the heavy metal transport in aquifer systems. In this study, the influences of LMWOAs on the transport of Cd2+ under different pH conditions in saturated porous media were evaluated. For this, three LMWOAs such as acetic acid, tartaric acid, and citric acid were employed. A two-site nonequilibrium transport model was applied to simulate the transport data. Under acidic conditions (pH 5.0), the results indicated that LMWOAs inhibited the transport of Cd2+ even at the low concentrations of organic acids (i.e., 0.05 and 0.1 mM). The inhibition effects might be attributed to the complexation role of the sand surface-bound organic acids and also electrostatic interaction. Meanwhile, the inhibition effects of LMWOAs on Cd2+ transport in the following order of citric acid > tartaric acid > acetic acid, which was also in agreement with the decreasing complex stability constants between Cd2+ and LMWOAs. This order may be dependent on their molecular structures (i.e., amount and type of functional groups) and complexing strength. Interestingly, when the LMWOA concentrations 0.5 mM, tartaric acid and citric acid still inhibited Cd2+ transport, while acetic acid slightly enhanced the Cd2+ mobility due to its weaker complexing strength. However, under neutral conditions (pH 7.0), LMWOAs generally enhanced the transport of Cd2+. The transport-enhancement of LMWOAs was ascribed to the formation of stable aqueous non-adsorbing Cd-organic acid complexes. In addition, citric acid could obviously inhibit the transport of Cd2+ under competitive transport conditions (i.e., with competing cations), which is mainly due to different complex affinities of citric acid to Pb2+ and Cd2+. These findings demonstrate that LMWOAs may inhibit or facilitate Cd2+ transport under different environmental conditions. Thus, environmental assessment concerning the transport of heavy metals should consider the roles of organic acids.


Assuntos
Poluentes do Solo , Cádmio , Peso Molecular , Porosidade , Solo
9.
Water Res ; 168: 115153, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31655441

RESUMO

A suite of biomarkers, including amino acids, pigments, and lignin phenols coupled with high resolution mass spectrometry were used to evaluate differences in the sources and fate of organic matter (OM) in Everglades treatment wetlands as a model for OM cycling in shallow water wetlands. Five components of the system (water column particulate matter, vertical traps, flocculent material, periphyton, and surface soil) were assessed for OM transformations down-profile (i.e. water column to soil) and between treatment cells dominated by emergent aquatic vegetation (EAV) and submerged aquatic vegetation (SAV), with comparisons to reference sites within the remnant Everglades. We found that OM cycling is fundamentally different between EAV and SAV wetlands, and that SAV wetlands have some shared characteristics with similar habitats in the remnant Everglades. Other than locations densely populated by Typha spp., water column particulate organic C was predominantly derived from microbial/cryptomonad sources, rather than macroscopic sources (vascular plants and algal mats). Bacterial amino acid biomarkers were positively correlated with amino acid degradation indices and organic P (Po), respectively suggesting that microbial abundance is associated with less degraded OM, and that further investigation into relationships between microbial biomass and Po is warranted. Overall, this multi-biomarker approach can elucidate the relative degradation of OM pools, identify sources of OM, and highlight the importance of water column processes in shallow water wetlands.


Assuntos
Purificação da Água , Áreas Alagadas , Biomarcadores , Plantas , Solo
10.
J Environ Manage ; 253: 109706, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31634743

RESUMO

Copper bioremoval efficiency and bioaccumulation capacity of Pseudomonas stutzeri LA3 isolated from copper contaminated soil were investigated. P. stutzeri LA3 removed about 50% of Cu (II) at 50 mg l-1 of concentration and accumulated a maximum of 1.62 mg of Cu g-1 biomass dry weight. Bioremediation by P. stutzeri LA3 partially depended on the production of extracellular polymeric substances, composed of proteins and carbohydrates. Cell surface alterations were observed on the Cu (II) treated biomass through a scanning electron microscope (SEM). Energy dispersive spectrometer (EDX) investigation of Cu (II) treated biomass showed clear signals of Cu, confirming the presence of copper ions on the cell surface. Fourier transform infrared spectroscopy (FTIR) showed the contribution of functional groups such as hydroxyl (-OH), carboxyl (-COOH), amide and amine (-NH2) in the remediation process. Based on the results, the isolated strain P. stutzeri LA3 could serve as a potential candidate for copper due to its significant copper removal effeciency.


Assuntos
Cobre , Pseudomonas stutzeri , Adsorção , Biodegradação Ambiental , Concentração de Íons de Hidrogênio , Mineração , Solo , Espectroscopia de Infravermelho com Transformada de Fourier
11.
J Environ Manage ; 253: 109584, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31634747

RESUMO

The environmental impacts of biosynthesized nanoparticles on the soil bacterial community assemblage and functions are not sufficiently understood. Given the broad application of silver nanoparticles (AgNPs), the present study aims to reveal the effects of biosynthesized AgNPs (~12 nm) on the soil bacterial community structure and functions. Specifically, we used a quantitative real-time PCR (qPCR) approach to quantify the relative abundance of bacterial taxon/group and representative functional genes (AOA, AOB, NirK, NirS, NosZ, and PhoD). Results showed high relative abundance of Actinobacteria (1.53 × 107, p = 0.000) followed by Alphaproteobacteria (1.18 × 106, p = 0.000) and Betaproteobacteria (2.01 × 106, p = 0.000) in the soil exposed to biosynthesized AgNPs (100 mg/kg soil) after 30 days of treatment. Bacteroidetes group was observed to be negatively affected by AgNPs treatment. In the case of functional genes abundance, more pronounced impact was observed after 30 days of application. The biosynthesized AgNPs treatment accounted for significant increase in the relative abundance of all targeted functional genes except NirS. We conclude that the biosynthesized AgNPs did not cause toxic effects on nitrifiers, denitrifiers and organic phosphorus metabolizing bacterial community. While AgNO3 caused higher toxicity in the soil bacterial community structure and function. Based on our findings, we propose two key research questions for further studies; (i) is there any adaptation strategy or silver resistance embraced by the soil microbial community? and (ii) are biosynthesized nanoparticles environmentally safe and do not pose any risk to the soil microbial community? There is a necessity to address these questions to predict the environmental safety of biosynthesized AgNPs and to apply appropriate soil management policies to avoid nanotoxicity. Since this study provides preliminary evidence for the positive response of the soil bacterial community structure and functions to biosynthesized AgNPs, additional investigations under different soil conditions with varying soil physico-chemical properties are required to authenticate their environmental impact.


Assuntos
Nanopartículas Metálicas , Solo , Bactérias , Prata , Microbiologia do Solo
12.
J Environ Manage ; 253: 109720, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31654932

RESUMO

Inclusion of cement in fly ash and slag mixed soils could potentially alter the leaching behavior of elements. This study investigated the leaching characteristics of calcium (Ca), magnesium (Mg), sulfur (S), manganese (Mn), barium (Ba) and chromium (Cr) from cement activated soil-fly ash, soil-slag mixtures and soil, fly ash, steel slag and cement alone. Batch water leach tests, acid neutralization capacity and pH-dependent leach tests were performed. Test results indicated that, effluent concentrations of Ca and Ba increased, while Mg concentrations decreased with cement additions. No consistent trend was observed between S concentrations and cement content. The leaching of Cr and Mn remained unaffected by cement incorporation. Results of this study showed that the solution pH had the greatest influence on the leaching behaviors of the elements. Ca, Mg, S and Mn followed cationic leaching patterns, whereas Ba showed both cationic and amphoteric leaching patterns. The highest concentrations of Cr were observed at extreme acidic conditions, followed by a concentration plateau at the pH range of 5.5-10, and subsequent decrease and increase in concentrations at pH of 11.5 and 13, respectively. Geochemical modeling results suggested that except for Cr, the leaching mechanisms of the elements were controlled by their sulfate and (hydr)oxide minerals. The leaching of Cr was possibly controlled by BaCrO4 and CaCrO4. It was observed that the presence of carbonate minerals did not play a significant role on the leaching mechanisms of the elements, when cement was used as an activator.


Assuntos
Cinza de Carvão , Poluentes do Solo , Cromo , Materiais de Construção , Solo
13.
J Environ Manage ; 253: 109717, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31655462

RESUMO

In the present study, the impact of different soil surface mulching, fertilization on phosphorus mineralization and bio-availability of spring maize at various growth stages and soil layers (0-20 and 20-40 cm soil layer) were evaluated. The results indicated that the contents of total P and Olsen-Phosphorus (Olsen-P) in the soils of 0-20 cm soil layer were significantly higher than those in the 20-40 cm soil layer at different stages. The addition of organic fertilizer significantly increased the soil total P and Olsen-P content in the 0-20 cm soil layer. The different surface mulching, no mulching (NM), gravel mulching (GM) and film mulching (FM) were significantly affected by the content of Olsen-P in both soil layers during the critical growth period of spring maize. The Ca10-P contents in both soil layers were the maximum in terms of the inorganic phosphorus content in soils with different surface mulching and different fertilization. Surface mulching significantly affected the transformation of inorganic phosphorus in different soil layers of dry-land farmland, and accelerated the increase of Ca2-P content (first phosphorus source) in 0-20 cm soil layer by GM and FM. In addition, phosphorus combined with inorganic nitrogen fertilizer increased Ca8-P (second Olsen-P source) to a certain extent, and reduced the relative content of Ca2-P (first phosphorus source). Compared with phosphate (P), nitrogen and phosphorus (NP) treatments, manure and nitrogen and phosphorus (MNP) treatments increased the contents of Ca2-P (first phosphorus source) and Ca8-P (second effective phosphorus source), while it reduced the insoluble phosphorus source (O-P) content.


Assuntos
Fertilizantes , Fósforo , Agricultura , China , Fazendas , Esterco , Nitrogênio , Solo
14.
J Environ Manage ; 253: 109719, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31666214

RESUMO

This study sought to evaluate the cumulative effect of the implementation of green space depressions to promote disconnection of impervious areas within residential lots on runoff generation and temporal patterns in a small urban area characterized by high imperviousness. Three hypothetical scenarios were proposed with variations in the disconnection rate (α) within the lot, the soil infiltration conditions, and the rainfall patterns. Simulations were performed using the Storm Water Management Model (SWMM) with the implementation of a high spatial resolution model which allowed the explicit representation of the routing runoff between distinct surfaces. The results revealed a linear relationship trend between the total amount of rainfall (P) and total runoff (q), with identification of a possible precipitation threshold above the point at which a more critical condition of runoff generation is established. The value of this threshold was shown to be dependent on the degree of efficiency of the receptor permeable areas, which is associated with the disconnection rate and infiltrability of the soil. The results also showed that for a very high disconnection rate and lower infiltrability, runoff can increase substantially, with significant changes in the hydrographs simulated for longer storm events.


Assuntos
Chuva , Movimentos da Água , Solo , Água
15.
J Environ Manage ; 253: 109746, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31666216

RESUMO

Horizontal silage bunkers produce leachate that contains contaminants that can be detrimental to the environment if released untreated. Vegetated filter strips are used to treat silage bunker runoff to prevent contamination of surface waters via infiltration, however increased infiltration poses risks to groundwater, particularly for nitrate (NO3-). Vegetated filter strip plots with a sandy loam soil, half of which are amended with biochar, were investigated to assess the treatment of silage bunker runoff over 20 application events. The subsurface effluent biological oxygen demand (BOD5), chemical oxygen demand (COD), and total phosphorus (TP) were reduced on average by 40%, 46%, and 75%, respectively, and there was no statistical difference between treatments. The total nitrogen (TN) was reduced by 49 and 64% for control and biochar plots, respectively, which was significantly different between treatments. Biochar significantly reduced nitrate nitrogen (NO3--N) leaching by 40% compared to the control, however, the NO3--N concentration in leachate was still high ranging from 0.19 to 191.04 mg NO3--N L-1 and 0.18-108.89 mg NO3--N L-1 for control and biochar plots, respectively. A mass balance suggests the primary mechanism for a decrease in TN and NO3--N leaching from biochar amended plots was greater retention of NO3--N and organic N (ORG-N) within the soil/biochar matrix. The development of oxygenated functional groups and/or formation of organomineral layer on the biochar surface likely enhanced N retention.


Assuntos
Carvão Vegetal , Silagem , Nitrogênio , Solo
16.
J Environ Manage ; 253: 109745, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31671323

RESUMO

Mowing is a common practice in grassland management. It removes the majority of current year's aboveground plant biomass and thus substantial amounts of nutrients residing in plant tissues. The responses of plant aboveground biomass and nutrients to mowing stubble height is of great importance for developing sustainable mowing regimes, however, they are not well understood. We studied the effects of 4-year annual mowing at different height on plant aboveground biomass, plant N, P and N:P ratio, and soil nutrients in an Inner Mongolian steppe. Six stubble heights were set respectively at 14 cm (M14), 12 cm (M12), 10 cm (M10), 8 cm (M8), 6 cm (M6) and less than 0.3 cm (M0) height to ground surface. A no-mowing treatment (CK) was also included, making seven treatments. The results show that plant biomass production increased under light mowing (stubble height  > 12 cm) but decreased under heavy mowing (stubble height  < 6 cm), and the optimal stubble height for sustainable mowing was 6-12 cm. Plant N and P concentrations increased with mowing intensity (i.e. with the decrease of mowing stubble height). Plant N:P ratio decreased for some species, but no a directional change was detected in plant N:P ratio at the community level, nor in soil organic carbon and nutrient concentrations across the stubble height treatments. Our results indicate that plant biomass and N & P respond quickly to mowing height, whereas the response of soil chemical properties is insignificant over the 4-year period. To elucidate variation of species compensatory growth along mowing intensity gradient and the mutual feedback mechanism of soil-plant in mowing grassland, long-term study at permanent sites with changing stubble heights should be strengthened.


Assuntos
Carbono , Solo , Biomassa , Pradaria , Nitrogênio , Nutrientes , Poaceae
17.
J Environ Manage ; 253: 109636, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31678688

RESUMO

Dibutyl phthalate (DBP) is a frequently detected farmland contaminant that is harmful to the environment and human health. In this study, a DBP-degrading endophytic Bacillus siamensis strain T7 was immobilized in rice husk-derived biochar for bioremediation of DBP-polluted agricultural soils. The effects of this microbe-biochar composite on the soil prokaryotic community and the mechanism by which it regulates DBP degradation, were also investigated. A supplement of T7-biochar composite not only significantly boosted DBP biodegradation in soil by raising the DBP degradation rate constant and half-life from 0.1979 d-1 and 2.3131 d to 0.2434 d-1 and 2.1062 d, respectively, but also impeded DBP uptake by leafy vegetables. The general bioremediation effect of T7-biochar alliance excelled pure T7 suspensions and biochar, by trapping more DBP and boosting its complete degradation in soil. Besides, the combination of strain T7 and biochar can increase the proportion of some beneficial bacteria and boost the functional diversity of soil prokaryotic community, then to a certain extent may reverse the negative effect of DBP pollution on the agricultural soils. These results indicate that the rice-husk-derived biochar is a proper media when utilizing functional microbes into environmental treatment. Overall, T7-biochar composite is a promising soil modifier for soil bioremediation and the production of DBP-free crops.


Assuntos
Bacillus , Poluentes do Solo , Biodegradação Ambiental , Carvão Vegetal , Dibutilftalato , Humanos , Solo , Verduras
18.
Rev Environ Contam Toxicol ; 249: 1-27, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30725190

RESUMO

Metals are major abiotic stressors of many organisms, but their toxicity in plants is not as studied as in microorganisms and animals. Likewise, research in plant responses to metal contamination is sketchy. Candidate genes associated with metal resistance in plants have been recently discovered and characterized. Some mechanisms of plant adaptation to metal stressors have been now decrypted. New knowledge on microbial reaction to metal contamination and the relationship between bacterial, archaeal, and fungal resistance to metals has broadened our understanding of metal homeostasis in living organisms. Recent reviews on metal toxicity and resistance mechanisms focused only on the role of transcriptomics, proteomics, metabolomics, and ionomics. This review is a critical analysis of key findings on physiological and genetic processes in plants and microorganisms in responses to soil metal contaminations.


Assuntos
Adaptação Fisiológica/fisiologia , Ecossistema , Metais/toxicidade , Plantas , Microbiologia do Solo , Poluentes do Solo/toxicidade , Animais , Fungos , Metais Pesados , Solo
19.
Rev Environ Contam Toxicol ; 249: 29-70, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30806801

RESUMO

In recent times there has been remarkable development in the field of soil ecotoxicology and risk assessment (RA) models. It is, however, debatable if these RA models are robust representatives for worldwide relevance. In order to investigate this, the current overview aims to address heavy metal threats to soil life in southern Africa by investigating present knowledge and consequences for RA using research in southern Africa as a case. To this end, the focus is on southern African soils, soil life and living conditions. To critically discuss these issues, we report on extensive research conducted in the southern African context and looked how comparable these findings are to RA models employed in the western world. This is done by providing an inventory of selected studies focused on the ecotoxicity of metals towards soil life. It is concluded that there is a dearth of information on southern African soil life, most of which are laboratory-based studies carried out by a handful of researchers. Future research incorporating the available information into a soil ecosystem assessment procedure is paramount. It is recommended that a starting point to tackle this might be the development of holistic sight-specific guidelines for ecological risk assessment at larger spatial scales (km2) which takes into cognizance landscapes, vegetation and faunal characteristics.


Assuntos
Monitoramento Ambiental , Metais Pesados/análise , Poluentes do Solo/análise , África Austral , Medição de Risco , Solo
20.
Rev Environ Contam Toxicol ; 249: 71-131, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30806802

RESUMO

Environmental contamination due to heavy metals (HMs) is of serious ecotoxicological concern worldwide because of their increasing use at industries. Due to non-biodegradable and persistent nature, HMs cause serious soil/water pollution and severe health hazards in living beings upon exposure. HMs can be genotoxic, carcinogenic, mutagenic, and teratogenic in nature even at low concentration. They may also act as endocrine disruptors and induce developmental as well as neurological disorders, and thus, their removal from our natural environment is crucial for the rehabilitation of contaminated sites. To cope with HM pollution, phytoremediation has emerged as a low-cost and eco-sustainable solution to conventional physicochemical cleanup methods that require high capital investment and labor alter soil properties and disturb soil microflora. Phytoremediation is a green technology wherein plants and associated microbes are used to remediate HM-contaminated sites to safeguard the environment and protect public health. Hence, in view of the above, the present paper aims to examine the feasibility of phytoremediation as a sustainable remediation technology for the management of metal-contaminated sites. Therefore, this paper provides an in-depth review on both the conventional and novel phytoremediation approaches; evaluates their efficacy to remove toxic metals from our natural environment; explores current scientific progresses, field experiences, and sustainability issues; and revises world over trends in phytoremediation research for its wider recognition and public acceptance as a sustainable remediation technology for the management of contaminated sites in the twenty-first century.


Assuntos
Biodegradação Ambiental , Metais Pesados , Poluentes do Solo , Plantas , Solo
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