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1.
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
2.
Rev Environ Contam Toxicol ; 249: 153-197, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30900073

RESUMO

Lead (Pb) is an extremely toxic metal for all living forms including plants. It enters plants through roots from soil or soil solution. It is considered as one of the most eminent examples of anthropogenic environmental pollutant added in environment through mining and smelting of lead ores, coal burning, waste from battery industries, leaded paints, metal plating, and automobile exhaust. Uptake of Pb in plants is a nonselective process and is driven by H+/ATPases. Translocation of Pb metal ions occurs by apoplastic movement resulting in deposition of metal ions in the endodermis and is further transported by symplastic movement. Plants exposed to high concentration of Pb show toxic symptoms due to the overproduction of reactive oxygen species (ROS) through Fenton-Haber-Weiss reaction. ROS include superoxide anion, hydroxyl radical, and hydrogen peroxide, which reach to macro- and micro-cellular levels in the plant cells and cause oxidative damage. Plant growth and plethora of biochemical and physiological attributes including plant growth, water status, photosynthetic efficiency, antioxidative defense system, phenolic compounds, metal chelators, osmolytes, and redox status are adversely influenced by Pb toxicity. Plants respond to toxic levels of Pb in varied ways such as restricted uptake of metal, chelation of metal ions to the root endodermis, enhancement in activity of antioxidative defense, alteration in metal transporters expression, and involvement of plant growth regulators.


Assuntos
Chumbo/toxicidade , Fenômenos Fisiológicos Vegetais , Plantas/efeitos dos fármacos , Poluentes do Solo/toxicidade , Antioxidantes , Espécies Reativas de Oxigênio
3.
Sci Total Environ ; 690: 1151-1161, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31470478

RESUMO

Shooting activities is an important source of Pb in contaminated soils. Lead accumulates in superficial soil horizons because of its low mobility, favouring its uptake by plants and representing a high transference risk to the trophic chain. A combination of phytoremediation with nanoremediation techniques can be used to recover firing range soils and decrease the mobility, bioavailability and toxicity of Pb. This study examines in depth the changes in Pb behaviour in firing range soils by adding hydroxyapatite nanoparticles (HANPs). These nanoparticles (NPs) may immobilise Pb and improve the quality of these areas. The use of HANPs and the Pb effects were assessed in three different species (Sinapis alba L., Lactuca sativa L. and Festuca ovina L.), focusing on their germination and early growth, through phytotoxicity assays. Single extractions with CaCl2 (0.01 M) in soils treated with HANPs show that these NPs retained Pb and reduced highly its availability and mobility. HR-TEM and TOF-SIMS were used to determine the interactions between HANPs and Pb, as well as with soil components. According to TOF-SIMS and HR-TEM/EDS analysis, Pb was mainly retained by HANPs but also associated lightly to organic matter, Fe compounds and silicates. Phytotoxicity assays exposed that S. alba, L. sativa and F. ovina were able to germinate and develop in the firing range soils despite the high available Pb contents before adding HANPs. After adding HANPs, Pb retention increased, favouring the germination and the growth of roots in the three species. These results suggest that HANPs can be used to decrease the availability and the toxicity of Pb without negative effects in the species growth. Accordingly, the combination of phytoremediation and nanoremediation techniques can be a great tool to stabilise these soils, avoiding the Pb transfer to nearby areas and its entry in the trophic chain.


Assuntos
Durapatita/química , Recuperação e Remediação Ambiental/métodos , Chumbo/toxicidade , Nanopartículas/química , Plantas/efeitos dos fármacos , Poluentes do Solo/toxicidade , Bioensaio , Solo , Armas
4.
Sci Total Environ ; 690: 1162-1169, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31470479

RESUMO

Perfluorinated compounds (PFCs) have been detected at various concentrations in different environment compartments due to their widespread usage. Nowadays, soil environment has become a prominent sink of PFCs from surface runoff and penetration, but few researches have been conducted in the toxicity of PFCs to soil microorganisms. To address the issue, microcalorimetry was applied to investigate the toxicity of six PFCs with different carbon chain length (4, 8, and 10) and functional group (carboxylic and sulfonic) to microbial activities in three Chinese soils varying widely in soil properties. Adsorption of PFCs by soil matrix was a key factor in controlling the toxicity of PFCs to soil microorganisms. The differences of carbon chain length and functional groups of PFCs have different impacts on soil microbial activity while affecting adsorption progress. Particularly, the sulfonic PFCs expressed higher toxicity than the carboxylic. It is also identified that the longer the chain length, the greater the toxicity of PFCs. Soil pH was another relevant factor of soil adsorption, and with the increase of pH, adsorption capability increased. Soil available P, N and K were essential nutrients in soil, and suggested to improve microbial activity under PFCs stress.


Assuntos
Monitoramento Ambiental , Fluorcarbonetos/toxicidade , Microbiologia do Solo , Poluentes do Solo/toxicidade , Carbono , Solo/química
5.
J Agric Food Chem ; 67(41): 11331-11339, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31529945

RESUMO

Chiral pesticides are often produced and applied without distinguishing the difference of enantiomers, which sometimes leads to overuse and inaccurate risk assessment. Imazalil is a widely used chiral fungicide; its parent and major metabolite R14821 (imazalil-M) are usually detected in environmental and plant samples. The enantioselective bioactivity of imazalil enantiomers to seven typical pathogens (e.g., Fulvia fulva) was explored. S-(+)-Imazalil showed 3.00-6.59 times higher bioactivity than its antipode for selected pathogens. Molecular docking partly explained the mechanism of enantioselectivity in bioactivity. S-(+)-Imazalil had a stronger hydrophobic interaction and lower energy conformation with binding sites than R-(-)-imazalil. The acute toxicity of S-(+)-imazalil was 1.23-fold and 2.25-fold more than R-(-)-imazalil to P. subcapitata and D. magna, respectively. And, S-(+)-imazalil-M had 2.21-fold and 1.70-fold higher toxicity than R-(-)-imazalil-M to P. subcapitata and D. magna, respectively. However, R-(-)-imazalil was 1.21 times more toxic than S-(+)-imazalil to D. rerio. The enantioselective dissipation of imazalil and imazalil-M was explored under greenhouse conditions. High-effective S-(+)-imazalil preferentially enriched in leaf and fruit of tomato and cucumber, and no enantioselective degradation was found in soil. Imazalil-M enantiomers formed in cucumber, leaf of cucumber, and tomato, and the EF values fluctuated between 0.332 and 0.499. The results could provide information for more accurate assessment of imazalil; they implicated that using S-(+)-imazalil could reduce pesticide input and the risk to D. rerio.


Assuntos
Fungicidas Industriais/química , Imidazóis/química , Poluentes do Solo/química , Verduras/química , Poluentes Químicos da Água/química , Animais , Ascomicetos/efeitos dos fármacos , Clorófitas/efeitos dos fármacos , Cucumis sativus/química , Daphnia/efeitos dos fármacos , Estabilidade de Medicamentos , Frutas/química , Fungicidas Industriais/toxicidade , Imidazóis/toxicidade , Lycopersicon esculentum/química , Simulação de Acoplamento Molecular , Solo/química , Poluentes do Solo/toxicidade , Estereoisomerismo , Poluentes Químicos da Água/toxicidade
6.
Ying Yong Sheng Tai Xue Bao ; 30(8): 2767-2774, 2019 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-31418202

RESUMO

To reveal the physiological effects of rice alleviated by cadmium-tolerant Pseudomonas aeruginosa under cadmium stress condition, the influences of bacterial strian on the root vigor and leaf physiological characteristics were analyzed under a set of hydroponic experiments involving adding bacteria suspension, empty carrier, microbial inoculum with 20 µmol·L-1 Cd. Cadmium-free treatment as control. The results showed that the root vigor was significantly inhibited, leaf photosynthetic rate decreased, and the contents of soluble protein, flavonoid and total phenols in rice leaves were reduced, while the contents of malondialdehyde (MDA) and superoxide anion(O2-·) increased significantly under cadmium stress condition. Compared with cadmium treatment, root vigors of rice were increased by 36.1%-42.5% and 49.4%-53.0% respectively in bacteria suspension and microbial inoculum additions, net photosynthetic rates in leaves were increased by 118.5%-147.1% and 137.6%-156.9%, and the contents of soluble protein were increased by 37.0%-49.3% and 37.7%-72.6%, respectively. For the bacteria suspension treatment, the activities of SOD, POD and CAT in leaves were increased by 25.8%-36.6%, 40.9%-55.9%, 24.0%-29.2%, and the activities of SOD, POD and CAT in leaves under microbial inoculum treatment were increased by 36.9%-42.6%, 82.7%-92.6% and 43.3%-52.2%, respectively, with the stimulative effects on antioxidation enzymes in rice leaves being higher than those of bacteria suspension. Compared with cadmium treatment, the contents of MDA and O2-· in rice leaves were reduced by 44.8%-54.7%, 29.4%-41.9% and 9.9%-10.2%, 3.0%-7.1% in microbial inoculum and bacteria suspension treatments, respectively. In contrast, the contents of flavonoids and total phenols were increased by 125.4%-135.7%, 100.8%-119.4% and 139.4%-146.7%, 115.0%-134.7%, respectively. In summary, P. aeruginosa and the microbial inoculum could promote rice seedling growth by improving root vigor and photosynthetic rate, as well as the contents of flavonoids and total phenols, which led to the fact that P. aeruginosa could significantly alleviate the stress of cadmium on rice.


Assuntos
Cádmio/toxicidade , Oryza/fisiologia , Folhas de Planta/fisiologia , Raízes de Plantas/fisiologia , Pseudomonas aeruginosa/fisiologia , Poluentes do Solo/toxicidade , Oryza/microbiologia , Folhas de Planta/microbiologia , Raízes de Plantas/microbiologia , Plântula , Estresse Fisiológico
7.
J Environ Sci Health B ; 54(7): 539-548, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31264931

RESUMO

Glyphosate (GLP) currently is one of the most widely used herbicides worldwide. The persistence of GLP and its major metabolite, aminomethylphosphonic acid (AMPA) in the environment has been described by other authors. This study was aimed at comparing the GLP and AMPA behavior in sandy and loamy sand soils after spiking with enhanced (445 µg g-1) concentrations of GLP in herbicide KLINIK® (Nufarm, Austria) and bioaugmentation followed by 40 days weathering and a consistent three-stage leaching in a laboratory column experiment. Soil samples were obtained from mineral topsoil (0-10 cm) within former agricultural lands where soil parent material was formed by glacigenic deposits. The total amount of GLP and AMPA collected during three leaching stages was significantly (p<.05) higher from columns with sandy soil, compared to loamy sand soil. Bioaugmentation resulted in considerably lower concentrations of AMPA in leachates, especially in the sets with sandy soil (p=.01). Leachates were tested using FTIR spectroscopy and Daphnia magna. Statistical analysis of the changes in Ntot, Ctot, K+, Mg2+, Al3+, Ca2+, Mn2+ and Fe3+ concentrations in soils after the leaching experiment revealed that the loamy sand soil was likely to be more sensitive to the addition of GLP and bioaugmentation than sandy soil.


Assuntos
Glicina/análogos & derivados , Poluentes do Solo/análise , Solo/química , Agricultura , Animais , Daphnia/efeitos dos fármacos , Glicina/análise , Glicina/química , Glicina/toxicidade , Herbicidas/análise , Herbicidas/química , Isoxazóis/análise , Compostos Organofosforados/análise , Compostos Organofosforados/química , Poluentes do Solo/química , Poluentes do Solo/toxicidade , Espectroscopia de Infravermelho com Transformada de Fourier , Tetrazóis/análise , Testes de Toxicidade
8.
Sci Total Environ ; 691: 605-610, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31325860

RESUMO

The potential for bioaccumulation and associated genotoxicity of nonextractable residues (NERs) of polycyclic aromatic hydrocarbon (PAHs) in long-term contaminated soils have not been investigated. Here we report research in which earthworms, Eisenia fetida, were exposed to a soil containing readily available benzo[a]pyrene (B[a]P) and highly sequestered B[a]P NERs aged in soil for 350 days. B[a]P bioaccumulation was assessed and DNA damage (as DNA single strand breaks) in earthworm coelomocytes were evaluated by comet assay. The concentrations of B[a]P in earthworm tissues were generally low, particularly when the soil contained highly sequestered B[a]P NERs, with biota-soil accumulation factors ranging from 0.6 to 0.8 kgOC/kglipid. The measurements related to genotoxicity, that is percentage (%) of DNA in the tails and olive tail moments, were significantly greater (p < 0.05) in the spiked soil containing readily available B[a]P than in soil that did not have added B[a]P. For example, for the soil initially spiked at 10 mg/kg, the percentage of DNA in the tails (29.2%) of coelomocytes after exposure of earthworms to B[a]P-contaminated soils and olive tail moments (17.6) were significantly greater (p < 0.05) than those of unspiked soils (19.6% and 7.0, for percentage of DNA in tail and olive tail moment, respectively). There were no significant (p > 0.05) differences in effects over the range of B[a]P concentrations (10 and 50 mg/kg soil) investigated. In contrast, DNA damage after exposure of earthworms to B[a]P NERs in soil did not differ from background DNA damage in the unspiked soil. These findings are useful in risk assessments as they can be applied to minimise uncertainties associated with the ecological health risks from exposure to highly sequestered PAH residues in long-term contaminated soils.


Assuntos
Benzo(a)pireno/toxicidade , Oligoquetos/fisiologia , Poluentes do Solo/toxicidade , Animais , Benzo(a)pireno/metabolismo , Ensaio Cometa , Dano ao DNA , Poluentes do Solo/metabolismo
9.
Ecotoxicol Environ Saf ; 182: 109399, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31279281

RESUMO

Soil washing with chelators, a viable method for treating soils contaminated with potentially toxic metals, has drawn increasing attentions. The objective of this study was to determine a new generation of mixed degradable chelating agents from N, N-bis (carboxymethyl) glutamic acid (GLDA), [S, S]-stereoisomer of ethyleneiaminedisucc--inic acid (EDDS), nitrilotriacetic acid (NTA), and citric acid (CA), and to evaluate its effectiveness and feasibility to reduce toxic metals contamination in two different agricultural soils. A comparative leaching test conducted on the four individual degradable chelating agents showed that the capacity of single chelator in mobilizing copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) varied significantly. Using a combination of GLDA and NTA was more advantageous than using a single chelating agent in extracting potentially toxic metals. The removal efficiencies of Cu, Zn, Cd, and Pb reached 38.2, 9.8, 71.4, and 19.5% for soil 1, and 25.0, 5.2, 59.7, and 18.5% for soil 2, respectively, at mixed chelator (MC) concentrations of 3 mmol/L (GLDA) and 2 mmol/L (NTA), pH of 6.0, and a contact time of 4.0 h. The effects of washing conditions, chelator concentration, pH values, and contact time on the removal efficiencies of target toxic metals were investigated. The results showed that the combined chelating agent has a lower pH dependence, making it feasible for a wider range of applications. The effects of the chelating agents on the morphological distribution of potentially toxic metals and the soil enzyme activity before and after the treatments were also studied. After washing, the content of the water-soluble, acid-soluble, reducible, and oxidizable target metals showed a certain degree of decrease. Although the activities of catalase, urease, and invertase appeared to be inhibited during a short period of time, their activities were stimulated and later promoted with the degradation of the chelating agent. In general, the chelating agent combination has a great potential for toxic metals leaching.


Assuntos
Metais Pesados/química , Poluentes do Solo/química , Cádmio , Quelantes/química , Ácido Cítrico/química , Metais Pesados/análise , Metais Pesados/toxicidade , Solo/química , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Zinco
10.
Ecotoxicol Environ Saf ; 182: 109421, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31301592

RESUMO

The environmental contamination of soil by metal oxide nanomaterials is a growing global concern because of their potential toxicity. We investigated the effects of Mg doped ZnO (Mg-nZnO) nanoparticles on a model soil microorganism Bacillus subtilis. Mg-nZnO exhibited only a moderate toxic effect on B. subtilis vegetative cells but was able to prevent biofilm formation and destroy already formed biofilms. Similarly, Mg-nZnO (≤1 mg/mL) was moderately toxic towards Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Salmonella enterica, Saccharomyces cerevisiae and murine macrophages. Engineered Mg-nZnO produced H2O2 and O2•- radicals in solutions of various salt and organic molecule compositions. A quantitative proteomic analysis of B. subtilis membrane proteins showed that Mg-nZnO increased the expression of proteins involved in detoxification of ROS, translation and biofilm formation. Overall, our results suggest that Mg-nZnO released into the environment may hinder the spreading, colonization and biofilm formation by B. subtilis but also induce a mechanism of bacterial adaptation.


Assuntos
Bacillus subtilis/efeitos dos fármacos , Nanopartículas/toxicidade , Poluentes do Solo/toxicidade , Óxido de Zinco/toxicidade , Animais , Biofilmes , Escherichia coli/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Camundongos , Óxidos/metabolismo , Proteômica , Solo , Microbiologia do Solo , Staphylococcus aureus
11.
Ecotoxicol Environ Saf ; 182: 109418, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31327493

RESUMO

Cigarette filters (butts) are currently the most abundant form of anthropogenic litter on the planet, yet we know very little about their environmental impacts on terrestrial ecosystems, including plant germination and primary production. When discarded, filters contain a myriad of chemicals resulting from smoking tobacco and some still contain unsmoked remnants. A greenhouse experiment was used to assess the impacts of discarded filters of regular or menthol cigarette, either from unsmoked, smoked, or smoked cigarettes with remnant tobacco, on the growth and development of Lolium perenne (perennial ryegrass) and Trifolium repens (white clover). After 21 days, shoot length and germination success were significantly reduced by exposure to any type of cigarette filter for the grass and clover. Although total grass biomass was not measurably affected, the root biomass and root:shoot ratio were less in the clover when exposed to filters from smoked regular cigarettes and those with remnant tobacco. Cigarette filters caused an increase in chlorophyll-a in clover shoots and an increase in chlorophyll-b in grass shoots. Accordingly, whilst the chlorophyll a:b ratio was increased in the clover exposed to cigarette filters, it was decreased in grass. This study indicates the potential for littered cigarette filters to reduce growth and alter short-term primary productivity of terrestrial plants.


Assuntos
Lolium/efeitos dos fármacos , Poluentes do Solo/toxicidade , Produtos do Tabaco/toxicidade , Trifolium/efeitos dos fármacos , Clorofila A , Ecossistema , Fabaceae , Lolium/crescimento & desenvolvimento , Poaceae , Fumaça , Tabaco , Trifolium/crescimento & desenvolvimento
12.
Ecotoxicol Environ Saf ; 182: 109431, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31301593

RESUMO

The objective of this study was to examine the response of soil archaeal communities to saline stress in different types of Cd-contaminated soils from the North China Plain. Increased soil salinity by addition of 0.5% sodium salts (NaCl: Na2SO4: NaHCO3: Na2CO3 = 1:9:9:1) increased available Cd concentration, resulting in decreased ratios of Cd2+/CdT and CdSO4/CdT and increased ratios of CdCln2-n/CdT in soil solution. Soil saline stress decreased archaeal abundance and diversity and changed major soil archaeal taxa. For example, increased saline stress enriched taxa in the archaeal phyla Thaumarchaeota and Euryarchaeota, and these enriched tolerant taxa had much stronger correlations with soil properties, such as soil pH, EC or Na+. In addition, some microbes with low abundances like Bathyarchaeia (no rank) and Candidatus Nitrosotenuis were found to closely correlate with soil pH, EC, Na+, and Cl-, indicating they might play disproportionate roles in regulating ecological functions in stressed habitats. These results suggest that saline stress modified the effect of Cd toxicity on soil archaeal communities in different types of Cd-contaminated soils.


Assuntos
Archaea/efeitos dos fármacos , Cádmio/toxicidade , Estresse Salino , Microbiologia do Solo , Poluentes do Solo/toxicidade , Archaea/fisiologia , Cádmio/química , China , Solução Salina , Salinidade , Cloreto de Sódio , Solo/química , Poluentes do Solo/química
13.
Ecotoxicol Environ Saf ; 182: 109430, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31306921

RESUMO

Agronomic strategies as intercropping might be applied to reduce plant-available copper (Cu) in Cu-contaminated soils. Thus, our aim was to characterize two different oat cultivars, Avena sativa L. cv. Fronteira and cv. Perona for their ability to tolerate and/or phytostabilize Cu. Copper toxicity reduced plant biomass of both cultivars. The exudate analysis revealed the presence of phenolic compounds and phytosiderophores, yet with a different pattern between the cultivars: cv. Fronteira showed a Cu-concentration and time-dependent release of phenolic compounds, while cv. Perona down-regulated this release during the second week of treatment. Copper concentration increased linearly in all the tissues analysed with increasing Cu concentration showing yet a different compartmentalization: cv. Fronteira and cv. Perona preferentially accumulated Cu in the apoplasm and symplast, respectively. This higher accumulation of Cu in the apoplasm strongly reduces the available binding sites, leading to a competitive absorption with other macro-and micronutrients (e.g. Ca, Mn, Zn). Furthermore, in both cultivars Cu toxicity led to a significant reduction of shoot phosphorus content. The ionomic profile and compartmentalization of Cu together with the root activities demonstrate the different tolerance mechanism towards Cu toxicity of the two oat cultivars. In particular, cv. Fronteira seems to adopt an exclusion strategy based on accumulating Cu in the apoplasm and on the exudation of phenolic compounds. Thus, this cultivar could reduce the mobility and the consequent soil bioavailability of Cu playing an important role as phytostabilizer plant in intercropping systems in Cu-contaminated vineyards or orchards.


Assuntos
Avena/efeitos dos fármacos , Cobre/toxicidade , Poluentes do Solo/toxicidade , Avena/química , Disponibilidade Biológica , Biomassa , Cobre/análise , Poluição Ambiental/análise , Raízes de Plantas/metabolismo , Solo/química , Poluentes do Solo/análise
14.
Ying Yong Sheng Tai Xue Bao ; 30(6): 2049-2055, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31257778

RESUMO

The effects of single and combined pollution of enrofloxacin and Cu on the digestive enzymes of earthworms were studied, based on the actual pollution of caused by the application of livestock feces in farmland soil. Results showed that single enrofloxacin (0.1-4 mg·kg-1, 28 d) did not affect protease, but inhibited cellulase and alkaline phosphatase, with an induced effect on acid phosphatase. Single Cu pollution (20-200 mg·kg-1, 28 d) had inhibitory effects on the four digestive enzymes in earthworms. The effects of combined exposures on the digestive enzymes were mainly negative, showing a synergistic increasing character of toxicity in cellulase and acid phosphatase activities. The response dynamics of digestive enzymes to exposure duration was regulatory response (3 d)-intense response (7 d)-reaction recovery (14 d)-chronic exposure (28 d). Chronic exposure results showed that the combined treatments containing high-dose pollutant (200 mg·kg-1 Cu or 4 mg·kg-1 ENR) had more ecological risk.


Assuntos
Cobre/toxicidade , Enrofloxacina/toxicidade , Oligoquetos/enzimologia , Poluentes do Solo/toxicidade , Animais , Metais Pesados , Oligoquetos/fisiologia , Solo
15.
Ecotoxicol Environ Saf ; 182: 109433, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31319244

RESUMO

In order to explore the effects of pH and accompanying ions on divalent cobalt (Co(II)) toxicity to the wheat root elongation, an improved biotic ligand model (BLM) to predict Co(II) toxicity was developed in solution culture. The results showed that the Co(II)-toxicity decreased with the increases of K+, Ca2+ and Mg2+ activities, and the activity of Na+ had no impact on the Co(II)-toxicity. High H+ activity reduced the Co(II)-toxicity by the competitive effect of H+, while low H+ activity affected the toxicity by the change in the type of Co(II) in culture medium. Co2+ and CoOH+ were toxic to wheat root elongation, and Co(OH)2 was not. On the basis of BLM theory, the conditional equilibrium constants for Co2+, CoOH+, H+, Mg2+, Ca2+, K+ were obtained: logKCoBL = 4.65, logKCoOHBL = 6.62, logKHBL = 4.53, logKMgBL = 3.65, logKCaBL = 2.36 and logKKBL = 2.17. Free Co2+ and CoOH+, and the competitions of K+, Mg2+ and Ca2+ were suggested to be considered when developing the Co(II)-BLM.


Assuntos
Cobalto/toxicidade , Raízes de Plantas/efeitos dos fármacos , Poluentes do Solo/toxicidade , Triticum/efeitos dos fármacos , Cátions/farmacologia , Ligantes , Modelos Biológicos , Sódio/toxicidade , Testes de Toxicidade , Triticum/fisiologia
16.
Ecotoxicol Environ Saf ; 182: 109436, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31325808

RESUMO

Copper (Cu) is an essential yet toxic metal, which holds the ability to induce production of reactive oxygen species (ROS) in living cells resulting in severe abiotic stress. Therefore, the aim of our current study was to investigate the effects of extrinsically added ascorbic acid (AA) on oxidative stress indicators and redox homoeostasis remediators in 7-day-old seedlings and 60-day-old plants of Brassica juncea L. (hyper-accumulator species) subjected to Cu (II) stress. Our findings showed that seed germination ballooned by 55.4% in Cu (II) stressed seedlings upon addition of 50 mg l-1 AA. Copper content accelerated in stressed seedlings and plants; however, a negative interaction was seen upon addition of AA. Both seedlings and plants exposed to Cu (II) accumulated free radicals such as H2O2 and superoxide anion, however, the addition of AA in the growth media decreased H2O2 and superoxide anion generation indicating ROS detoxification. Confocal microscopy also revealed improved cell viability and reduced H2O2 content because of enhanced antioxidant activity upon addition of AA as a protective chelate. Antioxidants such as ascorbate, flavonoids and glutathione rose significantly in Cu (II) stressed seedlings and plants in the presence of AA. Protein content increased by 51.3% and 47.5% in seedlings and plants growing in a binary combination of 100 mg l-1 Cu and AA (75 mg l-1 and 25 mg l-1), respectively. Sharp peaks for stress indicator amino acids such as cysteine and proline were seen in spectral analysis of B. juncea seedlings exposed to Cu (II). Protein thiols increased in plants grown in various binary doses Cu (II) and AA. This study provides sufficient evidence regarding the protective role of ascorbic acid (AA) against ROS and its suggested use as a soil amendment against Cu (II) toxicity in B. juncea.


Assuntos
Ácido Ascórbico/metabolismo , Cobre/toxicidade , Mostardeira/fisiologia , Poluentes do Solo/toxicidade , Antioxidantes/metabolismo , Cobre/metabolismo , Glutationa/metabolismo , Peróxido de Hidrogênio/metabolismo , Mostardeira/efeitos dos fármacos , Oxirredução , Estresse Oxidativo/fisiologia , Prolina/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Plântula/efeitos dos fármacos , Superóxido Dismutase/metabolismo
17.
Environ Pollut ; 253: 939-948, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31351302

RESUMO

The continued increase in the global demand for oil, which reached 4,488 Mtoe in 2018, leads to large quantities of petroleum products entering the environment posing serious risks to natural ecosystems if left untreated. In this study, we evaluated the impact of co-contamination with lead on the efficacy of two bioremediation processes, natural attenuation and biostimulation of Total Petroleum Hydrocarbons (TPH) as well as the associated toxicity and the changes in the microbial community in contaminated soils. The biostimulated treatment resulted in 96% and 84% reduction in TPH concentration in a single and a co-contamination scenario, respectively, over 28 weeks of a mesocosm study. This reduction was significantly more in comparison to natural attenuation in a single and a co-contamination scenario, which was 56% and 59% respectively. In contrast, a significantly greater reduction in the associated toxicity of in soils undergoing natural attenuation was evident compared with soils undergoing biostimulation despite the lower TPH degradation when bioassays were applied. The earthworm toxicity test showed a decrease of 72% in the naturally attenuated toxicity versus only 62% in the biostimulated treatment of a single contamination scenario. In a co-contamination scenario, toxicity decreased only 30% and 8% after natural attenuation and biostimulation treatments, respectively. 16s rDNA sequence analysis was used to assess the impact of both the co-contamination and the bioremediation treatment. NGS data revealed major bacterial domination by Nocardioides spp., which reached 40% in week 20 of the natural attenuation treatment. In the biostimulated soil samples, more than 50% of the bacterial community was dominated by Alcanivorax spp. in week 12. The presence of Pb in the natural attenuation treatment resulted in an increased abundance of a few Pb-resistant genera such as Sphingopyxis spp. and Thermomonas spp in addition to Nocardioides spp. In contrast, Pb co-contamination completely shifted the bacterial pattern in the stimulated treatment with Pseudomonas spp. comprising approximately 45% of the bacterial profile in week 12. This study confirms the effectiveness of biostimulation over natural attenuation in remediating TPH and TPH-Pb contaminated soils. In addition, the presence of co-contaminants (e.g. Pb) results in serious impacts on the efficacy of bioremediation of TPH in contaminated soils, which must be considered prior to designing any bioremediation strategy.


Assuntos
Biodegradação Ambiental/efeitos dos fármacos , Chumbo/toxicidade , Microbiologia do Solo , Poluentes do Solo/toxicidade , Bactérias/metabolismo , Ecossistema , Hidrocarbonetos/análise , Petróleo/análise , Petróleo/metabolismo , Pseudomonas/metabolismo , Solo , Poluentes do Solo/análise , Poluentes do Solo/metabolismo
18.
Environ Pollut ; 253: 959-965, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31351304

RESUMO

Application of Zinc (Zn) is considered an effective measure to reduce Cadmium (Cd) uptake and toxicity in Cd-contaminated soils for many plant species. However, interaction between Zn and Cd in rice plant is complex and uncertain. In this study, four indica rice cultivars were selected to evaluate the effect of Zn exposure in an EGTA-buffered nutrient solution under varying Zn activities and a field level of Cd activity to characterize the interaction between Zn and Cd in rice. Severe depression in shoots' biomass, tiller number, and SPAD (Soil and Plant Analyzer Development) value were found at both Zn deficiency and Zn phytotoxicity levels among four tested rice cultivars. There existed a strong antagonism interaction between Zn and Cd in both shoot and root from Zn deficiency to Zn phytotoxicity. The reduction of Cd accumulation in roots and shoots could be explained by the competition between Zn and Cd as well as the dilution effect of increasing biomass. The conflicting effect of Zn supply on Cd uptake may be attributed to the increasing transfer ratio of Cd from root to shoot with the increasing Zn2+ activities and the strong depression of Fe and Mn in shoots with the increasing Zn2+ activities as well as the variation of genotypes. Balance between Zn and Cd should be considered in field application.


Assuntos
Cádmio/metabolismo , Oryza/fisiologia , Poluentes do Solo/metabolismo , Zinco/metabolismo , Transporte Biológico/efeitos dos fármacos , Biomassa , Cádmio/análise , Poluição Ambiental , Oryza/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
19.
Bull Environ Contam Toxicol ; 103(3): 421-427, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31342131

RESUMO

In most laboratory studies with oral exposure of terrestrial invertebrates to metals an artificial food, which is easy to handle, is used. The bioavailability of metals from this artificial food may, however, be much higher than from more field relevant food sources. Such differences may affect toxicokinetic processes in different tissues. To test the effect of bioavailability of Cd in food on Cd toxicokinetics and internal distribution in terrestrial invertebrates, we performed the experiment using the ground beetle Pterostichus oblongopunctatus exposed to Cd via food differing in their soluble Cd pool. We showed that in carabids Cd accumulation and elimination pattern in different tissues is not governed by the metal availability in food.


Assuntos
Cádmio/toxicidade , Besouros/fisiologia , Poluentes do Solo/toxicidade , Animais , Disponibilidade Biológica , Cádmio/metabolismo , Metais , Poluentes do Solo/metabolismo , Toxicocinética
20.
Bull Environ Contam Toxicol ; 103(3): 416-420, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31342133

RESUMO

This study aimed at determining the competition of cadmium (Cd), lead (Pb), zinc (Zn) and copper (Cu) on their assimilation, on the food consumption and the growth of terrestrial isopod Porcellio laevis. Individuals were exposed to artificially contaminated litter of Quercus for 4 weeks and were weekly weighed. At the end of the experiment, the concentration of Cd, Pb, Zn and Cu in individuals were measured by atomic absorption spectrometry. Biological parameters such as growth, and bioaccumulation factor (BAF) were calculated and results from the various treatments were compared. Depending on metals, weight loss or gain were recorded for isopods during the four weeks of exposure. A weight loss was measured on individuals exposed to Cd-contaminated litter whereas a weight gain was highlighted for those exposed to the Zn-contaminated litter. BAF values revealed that P. laevis was macroconcentrator of Zn and Cu and deconcentrator of Cd and Pb.


Assuntos
Isópodes/fisiologia , Metais Pesados/toxicidade , Poluentes do Solo/toxicidade , Animais , Cádmio/análise , Cádmio/toxicidade , Cobre/toxicidade , Metais Pesados/análise , Zinco/análise , Zinco/toxicidade
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