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1.
J Hazard Mater ; 416: 125818, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492783

RESUMO

Metal pollution poses a significant threat to ecological security and human health. Current research on the causes, sources and distribution of metal pollution in the Yangtze River plain is lacking. This study investigated the accumulation, risk, distribution, and sources of heavy metals in 62 lakes along the Yangtze River, and analyzed the relationship between river-lake connectivity, economic structure, population and metal diffusion. The mean concentrations of Cr, Cu, Hg, Zn, Cd, Pb and As in the surface sediments of these lakes were 90.8, 60.1, 0.06, 102, 0.89, 42.7, and 6.01 mg/kg, respectively. Most (99%) of the lake sediments were contaminated with Cd, and the lakes in the middle reach and southern bank of the Yangtze River had a higher ecological risk. Cr originated from the natural environment, whereas Zn, Cu, Pb, Cd and As were affected by human activities. The lakes disconnected from the Yangtze River had higher concentrations of Cu, Zn, Pb and As, while the lakes connected to the river had higher concentrations of Cd and Cr. This comprehensive analysis determined the pollution characteristics of heavy metals, illustrated the causes of non-point pollution in the Yangtze River plain, and showed that soil-water erosion is important in metal diffusion.


Assuntos
Metais Pesados , Poluentes Químicos da Água , China , Monitoramento Ambiental , Sedimentos Geológicos , Humanos , Lagos , Metais Pesados/análise , Metais Pesados/toxicidade , Medição de Risco , Rios , Poluentes Químicos da Água/análise
2.
J Hazard Mater ; 416: 125909, 2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492843

RESUMO

Twenty-two water samples from the Thirumanimuthar River course in southern India were collected before COVID-19 lockdown and during COVID-19 lockdown periods and were analyzed for microbiological parameters (fecal coliform bacteria, total coliform bacteria, Escherichia coli, and fecal streptococci) and heavy metals (Fe, Mn, Zn, Cu, Cd, Ni, Pb and Cr). The lockdown has decreased microbial populations and heavy metals. Fe, Cu, Cd, Ni, Pb and Cr exceeded the drinking water limits, respectively, in 77%, 45%, 27%, 18%, 9% and 91% of the pre-lockdown samples. During the lockdown period, Fe, Cu and Cd concentrations in 23% and Cr in 50% of the samples exceeded the limits. Heavy Metal Pollution Index (PI) expressed that 27%, 64% and 9% of the pre-lockdown samples represented 'low', 'medium' and 'high' pollution categories, respectively, but 68% and 32% of the lockdown period samples represented 'low' and 'medium' categories, respectively. The Metal Index (MI) exposed that all samples of pre-lockdown were under the seriously affected category, whereas 54% and 46% of lockdown samples were under strongly and seriously affected categories, respectively. Health risk evaluation predicted that 95%, 91% and 86% of pre-lockdown samples and 45%, 36% and 33% of lockdown period samples were at risk among children, teenagers and adults, respectively. As there is no integrated study on river water quality of COVID-19 lockdown this work is uniquely carried out by combining heavy metal pollution, microbial contamination and human health risk evaluation.


Assuntos
COVID-19 , Metais Pesados , Poluentes Químicos da Água , Adolescente , Adulto , Criança , China , Controle de Doenças Transmissíveis , Monitoramento Ambiental , Sedimentos Geológicos , Humanos , Índia , Metais Pesados/análise , Metais Pesados/toxicidade , Pandemias , Medição de Risco , Rios , SARS-CoV-2 , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
3.
J Hazard Mater ; 416: 125942, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492869

RESUMO

A novel Ralstonia Bcul-1 strain was isolated from soil samples that was closest to Ralstonia pickettii. Broad-spectrum resistance was identified to a group of heavy metal ions and tolerance to concentrations of Cd2+ up to 400 mg L-1. Low concentrations of heavy metal ions did not have distinctive impact on heavy metal resistance genes and appeared to induce greater expression. Under exposure to Cd2+, cell wall components were significantly enhanced, and some proteins were also simultaneously expressed allowing the bacteria to adapt to the high Cd2+ living environment. The maximum removal rate of Cd2+ by the Ralstonia Bcul-1 strain was 78.97% in the culture medium supplemented with 100 mg L-1 Cd2+. Ralstonia Bcul-1 was able to survive and grow in a low nutrient and cadmium contaminated (0.42 mg kg-1) vegetable soil, and the cadmium removal rate was up to 65.76% in 9th growth. Ralstonia Bcul-1 mixed with biochar could maintain sustainable growth of this strain in the soil up to 75 d and the adsorption efficiency of cadmium increased by 16.23-40.80% as compared to biochar application alone. Results from this work suggests that Ralstonia Bcul-1 is an ideal candidate for bioremediation of nutrient deficient heavy metal contaminated soil.


Assuntos
Metais Pesados , Poluentes do Solo , Biodegradação Ambiental , Cádmio/toxicidade , Metais Pesados/toxicidade , Ralstonia , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
4.
J Hazard Mater ; 416: 126123, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492917

RESUMO

Toxicity biosensors have recently gained significant attention due to their potential use in online monitoring. However, the effects of toxicants and the influence of dose, exposure time, and type and concentration of respiration substrate (RS) on the performance of a bioreactor are species-specific. Although these factors need to be investigated case-by-case as they can lead either to damage or self-repair of the affected microorganisms, they have seldom been considered in previous studies. Therefore, this work examined, for the first time, the effects of resting time and RS concentration on the performance of the biosensing system for toxicity of Cr6+ in water. In addition, it is also the first time that a novel non-contact fluid delivery system was applied to a toxicity biosensing system to prevent unstable responses. By choosing the best RS concentration and balancing the resting and exposure times, the proposed procedure exhibits promising results in terms of minimum detectable concentration (MDC), limit of detection (LOD), detection range, linearity, sensitivity, reproducibility and accuracy. The recovery time was only a few hours and the coefficients of variation of inhibition and recovery were only 12% and 9.6%, respectively, during six times reuse over one month of storage.


Assuntos
Técnicas Biossensoriais , Metais Pesados , Intoxicação por Metais Pesados , Humanos , Metais Pesados/toxicidade , Reprodutibilidade dos Testes , Água
5.
J Hazard Mater ; 416: 126166, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492942

RESUMO

Heavy metal pollution is one of the primary challenges of water pollution, and the fabrication of highly effective, green and non-toxic adsorbents for heavy metals is urgently required on the basis of environmental and sustainable development strategies. Here, we report a novel fluorescent wood (FW) with effective adsorption ability (maximum theoretical adsorption capacity of 98.14 mg/g for hexavalent chromium [Cr(VI)]), good fluorescence properties (absolute quantum yield of 12.8%), non-cytotoxicity (cell viability of >90%) and high detection sensitivity and selectivity for Cr(VI). The FW was formed using a process involving delignification, infiltration with carbon dots, and free-radical polymerization with acrylic acid. Mechanistic analysis confirmed that the reconstructed 3D porous structure of the FW provided many effective sorption sites, such as amino, hydroxyl and carboxyl groups. This improved the adsorption ability and stabilized the fluorescence signal, which enhanced the detection ability. These factors give the novel FW considerable potential for use in the removal of Cr(VI) ions from wastewater.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Adsorção , Cromo/análise , Cromo/toxicidade , Concentração de Íons de Hidrogênio , Cinética , Metais Pesados/toxicidade , Águas Residuárias , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Madeira/química
6.
Environ Monit Assess ; 193(9): 620, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34476613

RESUMO

Potential toxic metals from natural and anthropogenic sources accumulate in soil and plants, and represent important environmental contamination challenges. The ecological and human health risks of the potential toxic metals in rice grain, paddy soil, and rice plants of Omor rice field were assessed. The total metal concentration from the four sampling sections (mg/kg) were soil-Zn (29.51 ± 2.23), Mn (55.27 ± 8.10), Cd (5.49 ± 2.24), Cu (2.94 ± 1.47), Pb (14.35 ± 6.54), and Cr (27.06 ± 8.31); rice grain-Zn (21.70 ± 5.44), Mn (3.30 ± 0.21), Cd (00.14 ± 0.11), Cu (2.80 ± 0.34), Pb (11.98 ± 0.58), and Cr (15.86 ± 2.79); and for rice plant-Zn (5.24 ± 1.93), Mn (4.68 ± 1.91), Cd (0.21 ± 0.11), Cu (4.88 ± 0.61), Pb (15.24 ± 6.16), and Cr (46.5 ± 6.05). The estimated daily intakes for adult showed that Cd and Pb exceeded the safe limit by 1% and 93%, respectively. The metal hazard quotients (Zn-0.0007, Mn-0.00019, Cd-0.16, Cu-0.19, and Cr-0.0000077) were less than 1 indicating no probable health risk originating from their exposure. The total hazard index (0.35) also suggests no probable health risk connected with the rice consumption. The metals' ecological risk indices of the soil showed low-risk (< 40), except Cd in some sections of the rice field which indicated moderate potential ecological risk (40-80).


Assuntos
Metais Pesados , Oryza , Poluentes do Solo , Adulto , China , Monitoramento Ambiental , Humanos , Metais Pesados/análise , Metais Pesados/toxicidade , Nigéria , Medição de Risco , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
7.
Chemosphere ; 282: 131048, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34470147

RESUMO

Antimicrobial resistance (AMR), as well as the development of biofilms in drinking water distribution systems (DWDSs), have become an increasing concern for public health and management. As bulk water travels from source to tap, it may accumulate contaminants of emerging concern (CECs) such as antibiotics and heavy metals. When these CECs and other selective pressures, such as disinfection, pipe material, temperature, pH, and nutrient availability interact with planktonic cells and, consequently, DWDS biofilms, AMR is promoted. The purpose of this review is to highlight the mechanisms by which AMR develops and is disseminated within DWDS biofilms. First, this review will lay a foundation by describing how DWDS biofilms form, as well as their basic intrinsic and acquired resistance mechanisms. Next, the selective pressures that further induce AMR in DWDS biofilms will be elaborated. Then, the pressures by which antibiotic and heavy metal CECs accumulate in DWDS biofilms, their individual resistance mechanisms, and co-selection are described and discussed. Finally, the known human health risks and current management strategies to mitigate AMR in DWDSs will be presented. Overall, this review provides critical connections between several biotic and abiotic factors that influence and induce AMR in DWDS biofilms. Implications are made regarding the importance of monitoring and managing the development, promotion, and dissemination of AMR in DWDS biofilms.


Assuntos
Água Potável , Metais Pesados , Antibacterianos/toxicidade , Biofilmes , Farmacorresistência Bacteriana , Humanos , Metais Pesados/toxicidade
8.
Environ Monit Assess ; 193(9): 584, 2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34406496

RESUMO

Microalgae are rich source of protein containing necessary amino acids at different levels. The present study was designed to assess stimulatory and/or inhibitory impact of five different concentrations (5, 10, 15, 20, and 25 mg/L) of three essential heavy metals (nickel, zinc, and copper) on protein content (soluble, insoluble, and total) of the marine unicellular green alga Dunaliella tertiolecta. Further, geospatial analyses were used to assess the suitability of Qaroun Lake for D. tertiolecta proliferation. The experimental results showed a gradual increase in protein content of D. tertiolecta with low concentrations of the three investigated heavy metals. However, increasing levels of heavy metals led to inhibitory effect on protein synthesis in alga with different grades. Ni, Zn and Cu levels in Qaroun lake were found suitable for the proliferation of Dunaliella (Lower than 5 mg/L). The present study highly recommends the necessity to encourage site selection of optimal marine environments suitable for the proliferation of marine algae rich in protein content.


Assuntos
Clorófitas , Metais Pesados , Microalgas , Monitoramento Ambiental , Metais Pesados/toxicidade , Zinco
9.
Ecotoxicol Environ Saf ; 223: 112578, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34352573

RESUMO

Heavy metal (HM) stress in plants has received considerable global attention as it threatens sustainable growth in agriculture worldwide. Hence, desperate efforts have been undertaken for combating the effects of this stress in plants. Interestingly, the use of phytohormones in reducing the impact of HM toxicity has gained much momentum in the recent past. Phytohormones act as chemical messengers that improve the HM stress resistance in plants, thus allowing them to retain their growth and developmental plasticity. Their exogenous application as well as manipulation of endogenous levels through precise targeting of their biosynthesis/signaling components is a promising approach for providing a protective shield against HM stress in plants. However, for the successful use of phytohormones for field plants exposed to HM toxicity, in-depth knowledge of the key pathways regulated by them is of prime importance. Hence, the present review mainly summarizes the key conceptual developments on the involvement of phytohormones in the mitigation of HM stress in plants. The role of various genes, proteins, and signaling components involved in phytohormones associated HM stress tolerance and their modulation has also been discussed. Thus, this update will pave the way for improving HM stress tolerance in plants with the advent of phytohormones for sustainable agriculture growth in the future.


Assuntos
Metais Pesados , Reguladores de Crescimento de Plantas , Agricultura , Metais Pesados/toxicidade , Plantas , Estresse Fisiológico
10.
Ecotoxicol Environ Saf ; 223: 112582, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34365209

RESUMO

Heavy metal pollution in the environment is mostly manifested as a multi-elemental compound pollution. The effect of the long-term exposure to heavy metal pollution on the gut microbes of insects has remained unknown. For the current work, the population of Eucriotettix oculatus living in mining areas around the Diaojiang River with a history of hundreds of years of pollution, was selected along with the similar species living in non-mining areas to conduct a comparative study of their gut microbes. The microbial communities were analyzed using 16S rRNA amplicon sequencing. The results showed Proteobacteria to be dominant among gut microbes of E. oculatus, but the abundance of Proteobacteria was significantly increased when the insects were exposed to the environment with heavy metal pollution. The symbiotic bacteria belonging to genus Wolbachia were found to be dominant among the insect population from the non-mining area group, while the pathogenic bacteria belonging to Aeromonas were dominant among the insect population of the mining area group. The diversity analysis showed that the gut microbial community diversity of E. oculatus was reduced in the heavy metal pollution habitat. The analysis of the differences in the gut microbial population and metabolic pathways of the two groups showed that the heavy metal pollution caused the increase in pathogenic bacteria among the gut microbes of E. oculatus, which might have a negative impact on the health of the host. At the same time, probiotics and the beneficial metabolism pathways were also found to increase and enhance, helping the host to resist the damage caused by heavy metal stress. This might be one of the strategies used by E. oculatus to adapt to heavy metal pollution.


Assuntos
Gafanhotos , Metais Pesados , Microbiota , Poluentes do Solo , Animais , Metais Pesados/análise , Metais Pesados/toxicidade , RNA Ribossômico 16S/genética , Solo , Microbiologia do Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
11.
J Environ Sci (China) ; 107: 150-159, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34412778

RESUMO

The black soldier fly larvae (BSFL) have been successfully applied to treat various organic wastes. However, the impacts of heavy metals on antibiotic resistance in the BSFL guts are poorly understood. Here, we investigated the effect of copper (exposure concentrations of 0, 100 and 800 mg/kg) on the antibiotic and metal resistance profiles in BSFL guts. A total of 83 antibiotic resistance genes (ARGs), 18 mobile genetic elements (MGEs) and 6 metal resistance genes (MRGs) were observed in larval gut samples. Exposure to Cu remarkably reduced the diversity of ARGs and MGEs, but significantly enhanced the abundances of gut-associated ARGs and MRGs. The levels of MRGs copA, czcA and pbrT were dramatically strengthened after Cu exposure as compared with CK (increased by 2.8-13.5 times). Genera Enterococcus acted as the most predominant potential host of multiple ARG, MGE and MRG subtypes. Meanwhile, high exposure to Cu aggravated the enrichment of potential pathogens in BSFL guts, especially for Escherichia, Enterococcus and Salmonella species. The mantel test and procrustes analysis revealed that the gut microbial communities could be a key determinant for antibiotic and metal resistance. However, no significant positive links were observed between MGEs and ARGs or MRGs, possibly suggesting that MGEs did not play a crucial role in shaping the ARGs or MRGs in BSFL guts under the stress of Cu. These findings extend our understanding on the impact of heavy metals on the gut-associated antibiotic and metal resistome of BSFL.


Assuntos
Dípteros , Metais Pesados , Animais , Cobre/toxicidade , Resistência Microbiana a Medicamentos/genética , Genes Bacterianos , Incidência , Larva , Metais Pesados/toxicidade
12.
Artigo em Inglês | MEDLINE | ID: mdl-34444410

RESUMO

The structural changes of microorganisms in soil are the focus of soil indicators research. The purpose of this study was to investigate the changes in the composition of the soil bacterial community in heavy metal-contaminated soil. A total of six soil samples (two sampling times) were collected from contaminated farmland at three different depths (surface, middle, and deep layer). The pH value was measured. The concentrations of heavy metals (Cr, Ni, Cu, Zn, Cd, and Pb) and the soil bacterial community were analyzed using ICP-OES and 16S rRNA gene sequencing. The results of the two samplings showed that the pH value in the deep layer decreased from 6.88 to 6.23, and the concentrations of Cu, Zn, Cd, and Pb, with a smaller ion radius, increased by 16-28%, and Shannon, Chao1 increased by ~13%. The bacteria community composition at the three depths changed, but Proteobacteria, Acidobacteria, and Actinobacteria were the dominant phyla. In the copper and zinc tolerance test, the isolated bacterium that was able to tolerate copper and zinc was Bacillus sp. We found that, the longer the heavy metal pollution was of concern, the higher the tolerance. These results can be used as references for the microbial remediation of heavy metal-contaminated farmland.


Assuntos
Metais Pesados , Poluentes do Solo , Bactérias/genética , China , Monitoramento Ambiental , Fazendas , Metais Pesados/análise , Metais Pesados/toxicidade , RNA Ribossômico 16S/genética , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
13.
BMC Plant Biol ; 21(1): 386, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34416873

RESUMO

BACKGROUND: The abiotic stress such as soil salinization and heavy metal toxicity has posed a major threat to sustainable crop production worldwide. Previous studies revealed that halophytes were supposed to tolerate other stress including heavy metal toxicity. Though HMAD (heavy-metal-associated domain) was reported to play various important functions in Arabidopsis, little is known in Gossypium. RESULTS: A total of 169 G. hirsutum genes were identified belonging to the HMAD gene family with the number of amino acids ranged from 56 to 1011. Additionally, 84, 76 and 159 HMAD genes were identified in each G. arboreum, G. raimondii and G. barbadense, respectively. The phylogenetic tree analysis showed that the HMAD gene family were divided into five classes, and 87 orthologs of HMAD genes were identified in four Gossypium species, such as genes Gh_D08G1950 and Gh_A08G2387 of G. hirsutum are orthologs of the Gorai.004G210800.1 and Cotton_A_25987 gene in G. raimondii and G. arboreum, respectively. In addition, 15 genes were lost during evolution. Furthermore, conserved sequence analysis found the conserved catalytic center containing an anion binding (CXXC) box. The HMAD gene family showed a differential expression levels among different tissues and developmental stages in G. hirsutum with the different cis-elements for abiotic stress. CONCLUSIONS: Current study provided important information about HMAD family genes under salt-stress in Gossypium genome, which would be useful to understand its putative functions in different species of cotton.


Assuntos
Adaptação Fisiológica/genética , Estudo de Associação Genômica Ampla , Genótipo , Gossypium/genética , Gossypium/fisiologia , Metais Pesados/toxicidade , Filogenia , Produtos Agrícolas/genética , Produtos Agrícolas/fisiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Variação Genética , Família Multigênica
14.
Environ Pollut ; 284: 117533, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34261227

RESUMO

The Pearl River Estuary (PRE) is the largest estuary in southern China and under high metal stress. In the present study, we employed an integrated method of transcriptomics and proteomics to investigate the ecotoxicological effects of trace metals on the Hong Kong oyster Crassostrea hongkongensis. Three oyster populations with distinct spatial distributions of metals were sampled, including the Control (Station QA, the lowest metal levels), the High Cd (Station JZ, the highest Cd), and the High Zn-Cu-Cr-Ni (Station LFS, with the highest levels of zinc, copper, chromium, and nickel). Dominant metals in oysters were differentiated by principal component analysis (PCA), and theirgene and protein profiles were studied using RNA-seq and iTRAQ techniques. Of the 2250 proteins identified at both protein and RNA levels, 70 proteins exhibited differential expressions in response to metal stress in oysters from the two contaminated stations. There were 8 proteins altered at both stations, with the potential effects on mitochondria and endoplasmic reticulum by Ag. The genotoxicity, including impaired DNA replication and transcription, was specifically observed in the High Cd oysters with the dominating influence of Cd. The structural components (cytoskeleton and chromosome-associated proteins) were impaired by the over-accumulated Cu, Zn, Cr, and Ni at Station LFS. However, enhanced tRNA biogenesis and exosome activity might help the oysters to alleviate the toxicities resulting from their exposure to these metals. Our study provided comprehensive information on the molecular changes in oysters at both protein and RNA levels in responding to multi-levels of trace metal stress.


Assuntos
Crassostrea , Metais Pesados , Poluentes Químicos da Água , Animais , China , Monitoramento Ambiental , Estuários , Hong Kong , Metais Pesados/análise , Metais Pesados/toxicidade , Proteômica , Transcriptoma , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
15.
Arch Environ Contam Toxicol ; 81(2): 272-284, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34272567

RESUMO

Soil, a connecting link between biotic and abiotic components of terrestrial ecosystem, receives different kinds of pollutants through various point and nonpoint sources. Among different sources of soil pollution, contaminated irrigation water is one of the most prominent sources affecting soils throughout the globe. The irrigation water (both surface and groundwater) is increasingly getting polluted with contaminants such as metal(loid)s due to various anthropogenic activities. The present study was conducted to analyze metal(loid) contents in agricultural soil samples (N = 24) collected from fields along the banks of rivers Beas and Sutlej flowing through Punjab state of India, using wavelength-dispersive X-ray fluorescence (WDXRF) spectroscopy. The soil samples were also analyzed for their genotoxic potential using Allium cepa root chromosomal aberration assay. The rivers Beas and Sutlej are contaminated with municipal and industrial effluents in different parts of Punjab. The soil samples analyzed were found to have higher contents of arsenic, cobalt and chromium in comparison with the reference values given by various international agencies. Pollution assessment using different indices like index of geo-accumulation, enrichment factor and contamination factor revealed that the soil samples were highly polluted with cobalt and arsenic. The Allium cepa assay revealed that maximum genotoxicity was found in soil samples having higher contents of As and Co. Pearson's correlation analysis revealed strong positive correlation between the different metal(loid)s which indicated common sources of these metal(loid)s. Therefore, efforts must be taken to reduce the levels of these metal(loid)s in these agricultural soils.


Assuntos
Metais Pesados , Poluentes do Solo , Dano ao DNA , Ecossistema , Monitoramento Ambiental , Metais Pesados/análise , Metais Pesados/toxicidade , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
16.
J Environ Manage ; 297: 113315, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34298350

RESUMO

The bacterial communities are challenged with oxidative stress during their exposure to bactericidal antibiotics, metals, and different levels of dissolved oxygen (DO) encountered in diverse environmental habitats. The frequency of antibiotic resistance genes (ARGs) and metal resistance genes (MRGs) co-selection is increased by selective pressure posed by oxidative stress. Hence, study of resistance acquisition is important from an evolutionary perspective. To understand the dependence of oxidative stress on the dissemination of ARGs and MRGs through a pathogenic bacterial population, 12 metagenomes belonging to gut, water and soil habitats were evaluated. The metagenome-wide analysis showed the chicken gut to pose the most diverse pool of ARGs (30.4 ppm) and pathogenic bacteria (Simpson diversity = 0.98). The most common types of resistances found in all the environmental samples were efflux pumps (13.22 ppm) and genes conferring resistance to vancomycin (12.4 ppm), tetracycline (12.1 ppm), or beta-lactam (9.4 ppm) antibiotics. Additionally, limiting DO level in soil was observed to increase the abundance of excision nucleases (uvrA and uvrB), DNA polymerase (polA), catalases (katG), and other oxidative stress response genes (OSGs). This was further evident from major variations occurred in antibiotic efflux genes due to the effect of DO concentration on two human pathogens, namely Salmonella enterica and Shigella sonnei found in all the selected habitats. In conclusion, the microbial community, when challenged with oxidative stress caused by environmental variations in oxygen level, tends to accumulate higher amounts of ARGs with increased dissemination potential through triggering non-lethal mutagenesis. Furthermore, the genetic linkage or co-occurrence of ARGs and MRGs provides evidence for selecting ARGs under high concentrations of heavy metals.


Assuntos
Metais Pesados , Microbiota , Antibacterianos/farmacologia , Resistência Microbiana a Medicamentos/genética , Genes Bacterianos , Humanos , Metais Pesados/toxicidade , Estresse Oxidativo
17.
Artigo em Inglês | MEDLINE | ID: mdl-34205068

RESUMO

Concentrations of potentially toxic elements (PTEs) (Al, As, Cd, Cr, Cu, Ni, Pb, and Zn) were measured in topsoil samples collected from parks in the cities of Salzburg (Austria), Thessaloniki (Greece), and Belgrade (Serbia) in order to assess the distribution of PTEs in the urban environment, discriminate natural (lithogenic) and anthropogenic contributions, identify possible sources of pollution, and compare levels of pollution between the cities. An assessment of the health risks caused by exposure to PTEs through different pathways was also conducted. The study revealed that, with the exception of Pb in Salzburg, levels of PTEs in the soils in polluted urban parks were higher than in unpolluted ones, but still lower than those recorded in other European soils. Results of sequential analyses showed that Al, Cr, and Ni were found in residual phases, proving their predominantly lithogenic origin and their low mobility. In contrast, the influence of anthropogenic factors on Cu, Pb, and Zn was evident. Site-dependent variations showed that the highest concentrations of As, Cu, Pb, and Zn of anthropogenic origin were recorded in Salzburg, while the highest levels of Al, Cr, and Ni of lithogenic origin were recorded in Belgrade and Thessaloniki, which reflects the specificity of the geological substrates. Results obtained for the health risk assessment showed that no human health risk was found for either children or adults.


Assuntos
Metais Pesados , Poluentes do Solo , Adulto , Áustria , Criança , Cidades , Monitoramento Ambiental , Grécia , Humanos , Metais Pesados/análise , Metais Pesados/toxicidade , Medição de Risco , Sérvia , Solo , Poluentes do Solo/análise
18.
Sci Total Environ ; 794: 148629, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34217090

RESUMO

Coal is the main energy source in China, with 4.5 billion metric tons of coal gangue accumulating near the mining areas in the process of coal mining. The objectives of the present study were to identify the health risks to children from soil pollution caused by coal gangue accumulation and to clarify the possible developmental neurotoxicity caused by this accumulation using zebrafish (Danio rerio) as a model. The results reveal that As and seven other heavy metals in soil samples from the gangue dumping area to the downstream villages exhibited distance-dependent concentration variations and posed substantial potential non-carcinogenic risks to local children. Additionally, soil leachate could affect the key processes of early neurodevelopment in zebrafish at critical windows, mainly including the alterations of cytoskeleton regulation (α1-tubulin), axon growth (gap43), neuronal myelination (mbp) and synapse formation (sypa, sypb, and psd95), eventually leading to hypoactivity in the zebrafish larvae. These findings suggest the possible health risks of soil pollution in the coal gangue stacking areas to children, particularly affecting their early neurodevelopment.


Assuntos
Minas de Carvão , Metais Pesados , Poluentes do Solo , Animais , Criança , China , Carvão Mineral/análise , Monitoramento Ambiental , Humanos , Larva , Metais Pesados/análise , Metais Pesados/toxicidade , Medição de Risco , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Peixe-Zebra
19.
Sci Total Environ ; 794: 148611, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34225150

RESUMO

Water scarcity is becoming an alarming issue in the Mediterranean countries. Therefore, using the treated wastewater in the irrigation is considered as a valuable option. However, uncontrolled and long-term irrigation by wastewater leads to human health and environmental damages, mainly related to some specific pollutants. The assessment of the availability and toxicity of the heavy metals after long term irrigation, under semi-arid climate, is not yet well documented. In this study, physicochemical properties, genotoxicity (Vicia faba micronucleus test), total and available (CaCl2-extractable) concentrations of Cr, Pb, Cu, Zn, Co and Cd in eight soils of peri-urban farms irrigated with wastewater were examined to evaluate their accumulation. The results indicated that long-term irrigation with wastewater induced significant increase of electrical conductivity, organic matter, calcium carbonate equivalent and nutrient availability. Total and available concentration of heavy metals were significantly higher (P < 0.05) in irrigated soils by wastewater. The total concentrations of Zn, Pb, Cu, Cr, Cd and Co in irrigated soils by wastewater at 0-40 cm depth were 85.69, 43.94, 34.86, 14.62, 9.94 and 7.17 mg kg-1, respectively. Furthermore, the increase of the available metal fraction in irrigated soils by wastewater at 0-40 cm depth followed the following order: Co (1270.1%) > Cd (914.5%) > Cu (881.5%) > Cr (471.2%) > Pb (230.8%) > Zn (223.8%). The micronucleus assay indicated significant increase of micronucleus frequencies (41.25‰, 35.48‰, 21.66‰, 16.23‰ and 13.62‰ respectively for P1, P2, P3, P4 and P7) which were higher than the negative control (0‰) and the irrigated soil by fresh water (3.29‰). The micronucleus induction was significantly correlated with the high available fraction of Cd, Co and Zn at P1, P2 and P7. The genotoxicity can be a powerful test to assess the ecological effects associated with the interactions of heavy metals with other pollutants.


Assuntos
Metais Pesados , Poluentes do Solo , Irrigação Agrícola , Dano ao DNA , Monitoramento Ambiental , Humanos , Metais Pesados/análise , Metais Pesados/toxicidade , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Águas Residuárias/análise
20.
Environ Res ; 200: 111730, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34293315

RESUMO

Phytoremediation has been increasingly used as a green technology for the remediation of heavy metal contaminated soils. Microorganisms could enhance phytoremediation efficiency by solubilizing heavy metal and improve plant growth by producing phytohormones in the heavy metal contaminated soils. In this study, we investigated the abundance and composition of soil microbial communities in heavy metal contaminated soils. Furthermore, we identified a Cd-resistant fungal strain Penicillium janthinellum ZZ-2 and assessed its potential in improving plant growth, Cd accumulation and Cd tolerance in bermudagrass. The results indicated that long-term heavy metal pollution decreased microbial biomass and activity by inhibiting microbial community diversity, but did not significantly affect community composition. Mainly, the relative abundance of some specific bacterial and fungal taxa, such as Actinobacteria, Chloroflexi, Bacteroidetes, Ascomycota and Basidiomycota, changes under metal pollution. Furthermore, at genus level, certain microbial taxa, such as Pseudonocardiaceae, AD3, Latescibacteria, Apiotrichum and Paraboeremia, only exist in polluted soil. One Cd-resistant fungus ZZ-2 was isolated and identified as Penicillium janthinellum. Further characterization revealed that ZZ-2 had a greater capacity for Cd2+ absorption, produced indole-3-acid (IAA), and facilitated plant growth in the presence of Cd. Interestingly, ZZ-2 inoculation significantly increased Cd uptake in the stem and root of bermudagrass. Thus, ZZ-2 could improve plant growth under Cd stress by reducing Cd-toxicity, increasing Cd uptake and producing IAA. This study suggests a novel fungus-assisted phytoremediation approach to alleviate Cd toxicity in heavy metals contaminated soils.


Assuntos
Metais Pesados , Poluentes do Solo , Biodegradação Ambiental , Cádmio/toxicidade , Cynodon , Metais Pesados/análise , Metais Pesados/toxicidade , Penicillium , Solo , Microbiologia do Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
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