Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.220
Filtrar
1.
Chemosphere ; 244: 125579, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32050351

RESUMO

Although Solanum nigrum L. is a phytoremediator for different metals, its growth and physiology are still compromised by toxic levels of zinc (Zn). Thus, the development of eco-friendly strategies to enhance its tolerance, maintaining remediation potential is of special interest. This study evaluated the potential of 24-epibrassinolide (24-EBL) to boost S. nigrum defence against Zn towards a better growth rate and remediation potential. After 24 days of exposure, the results revealed that Zn-mediated inhibitory effects on biomass and biometry were efficiently mitigated upon application of 24-EBL, without affecting Zn accumulation. The evaluation of oxidative stress markers reported that Zn excess stimulated the accumulation of superoxide anion (O2.-), but reduced hydrogen peroxide (H2O2) levels, while not altering lipid peroxidation (LP). This was accompanied by an up-regulation of the antioxidant system, especially proline, superoxide dismutase (SOD) and ascorbate peroxidase (APX) in both organs, and ascorbate in roots of Zn-exposed plants. Foliar application of 24-EBL, however, induced distinctive effects, lowering proline levels in both organs, as well as APX activity in shoots and SOD in roots, whilst stimulating GSH and total thiols in both organs, as well as SOD and APX activity, in shoots and in roots, respectively. Probably due to a better antioxidant efficiency, levels of O2.- and H2O2 in pre-treated plants remained identical to the control, while LP further decreased in shoots. Overall, our results indicate a protective effect of 24-EBL on S. nigrum response to excess Zn, contributing for a better tolerance and growth rate, without disturbing its phytoremediation potential.


Assuntos
Brassinosteroides/metabolismo , Poluentes do Solo/toxicidade , Solanum nigrum/fisiologia , Esteroides Heterocíclicos/metabolismo , Zinco/toxicidade , Antioxidantes/farmacologia , Ascorbato Peroxidases/metabolismo , Ácido Ascórbico/farmacologia , Biodegradação Ambiental , Catalase/metabolismo , Peróxido de Hidrogênio/farmacologia , Peroxidação de Lipídeos , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Raízes de Plantas/metabolismo , Superóxido Dismutase/metabolismo , Zinco/análise
2.
Chemosphere ; 242: 125231, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31704521

RESUMO

A large number of metals is present in aquatic ecosystems, often occurring simultaneously, however, the isolated toxicity of them are better well known than their mixtures. Based on that, for the first time we aimed to test the effects of zinc (Zn) and aluminum (Al) mixtures to the microalgae Raphidocelis subcapitata. Regarding isolated toxicity, the 96 h IC50 of Zn and Al based on specific growth rates occurred, respectively, at 0.40 and 27.40 µM, thus Zn was ≈70-fold more toxic than Al. Both Zn and Al altered the cell size and complexity of R. subcapitata at the highest concentrations, although only during Zn exposure was the chlorophyll a fluorescence significantly diminished. Microalgae exposed to Al produced more ROS than during Zn exposure. Moreover, algae produced less ROS at the highest Zn concentration than in the lower concentrations. According to species sensitivity curves (SSD), R. subcapitata was the most sensitive organism to Zn and one of the most sensitive to Al. With respect to mixture toxicity tests, there were significant deviations for both CA (concentration addition) and IA (independent action) models, although data best fitted the CA model and DL (dose level-dependence) deviation, in which metals showed synergic effects at low concentrations and antagonist effects at higher concentrations.


Assuntos
Alumínio/toxicidade , Ecotoxicologia/métodos , Microalgas/efeitos dos fármacos , Zinco/toxicidade , Clorofila A/metabolismo , Sinergismo Farmacológico , Metais/toxicidade , Espécies Reativas de Oxigênio/metabolismo , Testes de Toxicidade/métodos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
3.
Aquat Toxicol ; 218: 105363, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31783302

RESUMO

The aquatic environment is continuously under threat because it is the final receptor and sink of waste streams. The development of industry, mining activities and agriculture gave rise to an increase in metal pollution in the aquatic system. Thus a wide occurrence of metal mixtures exists in the aquatic environment. The assessment of mixture stress remains a challenge considering that we can not predict the toxicity of a mixture on the basis of single compounds. Therefore the analysis of the effects of environmentally relevant waterborne mixtures is needed to improve our understanding of the impact of metal pollution in aquatic ecosystems. Our aim was to assess whether 10 % of the concentration of the 96 h LC50 (the concentration that is lethal to 50 % of the population in 96 h) of individual metal exposures can be considered as a "safe" concentration when applied in a trinomial mixture. Therefore, common carp were exposed to a sublethal mixture of Cu 0.07 ±â€¯0.001 µM (4.3 ±â€¯0.6 µg/L), Zn 2.71 ±â€¯0.81 µM (176.9 ±â€¯52.8 µg/L) and Cd 0.03 ±â€¯0.0004 µM (3.0 ±â€¯0.4 µg/L) at 20 °C for a period of one week. Parameters assessed included survival rate, bioaccumulation and physiological biomarkers related to ionoregulation and defensive mechanisms such as MT induction. Our results showed a sharp increase in Cu and Cd concentration in gills within the first day of exposure while Zn levels remained stable. The accumulation of these metals led to a Na drop in gills, liver and muscle as well as a decreased K content in the liver. Biomarkers related to Na uptake were also affected: on the first day gene expression for H+-ATPase was transiently increased while a concomitant decreased gene expression of the Na+/H+ exchanger occurred. A fivefold induction of metallothionein gene expression was reported during the entire duration of the experiment. Despite the adverse effects on ionoregulation all fish survived, indicating that common carp are able to cope with these low metal concentrations, at least during a one week exposure.


Assuntos
Bioacumulação , Cádmio/toxicidade , Carpas/metabolismo , Cobre/toxicidade , Poluentes Químicos da Água/toxicidade , Zinco/toxicidade , Animais , Bioacumulação/genética , Biomarcadores/metabolismo , Cádmio/metabolismo , Carpas/genética , Cobre/metabolismo , Ecossistema , Eletrólitos/metabolismo , Expressão Gênica/efeitos dos fármacos , Homeostase/efeitos dos fármacos , Dose Letal Mediana , Metalotioneína/genética , ATPases Translocadoras de Prótons/genética , Poluentes Químicos da Água/metabolismo , Zinco/metabolismo
4.
Chemosphere ; 240: 124915, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31563105

RESUMO

In animal livestock heavy metals are widely used as feed additives to control enteric bacterial infections as well as to enhance the integrity of the immune system. As these metals are only partially adsorbed by animals, the content of heavy metals in manure and wastewaters causes soil and ground water contamination, with Zn2+ and Cu2+ being the most critical output from pig livestock. Phytoremediation is considered a valid strategy to improve the purity of wastewaters. This work studied the effect of Zn2+ and Cu2+ on the morphology and protein expression in Thelypteris palustris and Typha latifolia plants, cultured in a wetland pilot system. Despite the absence of macroscopic alterations, remodeling of cell walls and changes in carbohydrate metabolism were observed in the rhizomes of both plants and in leaves of Thelypteris palustris. However, similar modifications seemed to be determined by the alterations of different mechanisms in these plants. These data also suggested that marsh ferns are more sensitive to metals than monocots. Whereas toleration mechanisms seemed to be activated in Typha latifolia, in Thelypteris palustris the observed modifications appeared as slight toxic effects due to metal exposure. This study clearly indicates that both plants could be successfully employed in in situ phytoremediation systems, to remove Cu2+ and Zn2+ at concentrations that are ten times higher than the legal limits, without affecting plant growth.


Assuntos
Biodegradação Ambiental/efeitos dos fármacos , Cobre/toxicidade , Traqueófitas/metabolismo , Typhaceae/metabolismo , Eliminação de Resíduos Líquidos/métodos , Zinco/toxicidade , Animais , Parede Celular/efeitos dos fármacos , Parede Celular/metabolismo , Cobre/farmacocinética , Gado , Esterco , Projetos Piloto , Células Vegetais/efeitos dos fármacos , Células Vegetais/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Proteínas de Plantas , Especificidade da Espécie , Suínos , Traqueófitas/efeitos dos fármacos , Typhaceae/efeitos dos fármacos , Águas Residuárias/química , Águas Residuárias/toxicidade , Poluentes Químicos da Água/farmacocinética , Poluentes Químicos da Água/toxicidade , Áreas Alagadas , Zinco/farmacocinética
5.
Chemosphere ; 239: 124720, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31499313

RESUMO

Cathodic protection by galvanic anodes (GACP) is often used to protect immerged metallic structures in harbor environments, especially GACP employing aluminum-based anodes. To follow a previous study that was performed in a laboratory on Al-anode, two monitoring periods were performed in parallel, one in an in situ environment (in the Port of Calais) for 42 months and the other in a laboratory for 18 months, to evaluate the transfer of metals constituting the Al-anode towards the sedimentary compartment. During each monitoring, two conditions of agitation of water (weak and strong) were compared, and different factors of sediment quality were used to assess the enrichment and potential toxic effects of these released metals. The results showed that the dissolution of Al-anode-induced a greater Zn enrichment of sediment than an Al enrichment. This is in contrast with the abundance of these elements present in the composition of the anode and suggested a potential toxic effect for marine organisms with regards to the discovered Zn level, especially in confined areas.


Assuntos
Alumínio , Eletrodos/efeitos adversos , Monitoramento Ambiental/métodos , Sedimentos Geológicos/análise , Organismos Aquáticos , Sedimentos Geológicos/química , Metais Pesados/análise , Poluentes Químicos da Água/análise , Zinco/análise , Zinco/toxicidade
6.
Chemosphere ; 239: 124814, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31527003

RESUMO

The increasing use of zinc oxide nanoparticles (ZnO NPs) in agriculture renders it necessary to evaluate their impact on soil non-target organisms. This work studies Zn availability to earthworms from the ZnO (NP and bulk) applied to two agricultural soils with a different pH at 20, 225, 500, and 1000 mg Zn kg-1. Zn uptakes and the effects on Eisenia andrei, grown under controlled conditions, were determined. Effects were assessed at three levels: organisms, mortality, growth and reproduction; biochemical, catalase and glutathione S-transferase activities, malondialdehyde (MDA), and protein content; cellular in coelomocytes, reactive oxygen species (ROS) generation, lysosomal membrane alterations (RN) and mitochondrial dysfunction (MTT). Available Zn was 100-fold higher in acidic than in calcareous soil and did not differ among ZnO (NP or bulk). Zn in worms was auto-regulated regardless of the soil Zn concentration, pH and ZnO size. Effects on mortality and weight were observed only in the acidic soil at the highest concentration, ZnO NPs reduced survival and body weight, while ZnO bulk reduced body weight. Reproduction parameters in acidic soil were: EC50 (fecundity) 277 and 256 mg Zn kg-1 and EC50 (fertility) 177 and 179 mg Zn kg-1 for ZnO NPs and bulk, respectively, with no found NP-specific effects. No responses of enzymatic activities, MDA and MTT were detected. ROS and RN were altered in the coelomocyte cells of earthworms in the two soils, but effects depended on ZnO size suggesting nanospecific effects. Soil pH governs toxicity more than ZnO size regardless of body Zn concentration.


Assuntos
Agricultura , Nanopartículas/química , Oligoquetos/efeitos dos fármacos , Solo/química , Óxido de Zinco/química , Zinco/farmacocinética , Animais , Peso Corporal/efeitos dos fármacos , Enzimas/metabolismo , Concentração de Íons de Hidrogênio , Poluentes do Solo/química , Poluentes do Solo/toxicidade , Taxa de Sobrevida , Zinco/química , Zinco/toxicidade , Óxido de Zinco/metabolismo , Óxido de Zinco/toxicidade
7.
Environ Toxicol ; 35(1): 5-14, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31452338

RESUMO

Superoxide dismutase (SOD) acts as the first line of defense against reactive oxygen species (ROS) within cells. In the present study, we determined two novel CuZnSOD genes (designated as CeCSD1 and CeCSD2) from the toxicity-testing freshwater algae Closterium ehrenbergii and examined their structural features, phylogenetic relationships, and gene expression under exposure to different metals. Putative CeCSD1 (204 aa, 20.6 kDa) and CeCSD2 (155 aa, 15.3 kDa) proteins had conserved CuZnSOD family motifs and metal (Cu, Zn) binding sites, but different N-terminus structures, that is, CeCSD1 has a signal peptide to chloroplasts. Phylogenetic analysis of each protein revealed that C. ehrenbergii was well clustered with other green algae and plants. Real-time PCR results showed that the gene expression obviously increased with heavy metal exposure. In addition, excess copper considerably increased the SOD activity and ROS generation but decreased the photosynthetic efficiency in treated cells. These results suggest that CeCSDs are involved in the antioxidant defense system and can be regarded as potential biomarkers for monitoring metal contaminants in aquatic environments.


Assuntos
Closterium/efeitos dos fármacos , Cobre/toxicidade , Água Doce , Expressão Gênica/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Zinco/toxicidade , Antioxidantes/metabolismo , Closterium/enzimologia , Cobre/metabolismo , Estresse Oxidativo/genética , Fotossíntese/efeitos dos fármacos , Fotossíntese/genética , Filogenia , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/genética , Superóxido Dismutase-1/genética , Superóxido Dismutase-1/metabolismo , Zinco/metabolismo
8.
Environ Pollut ; 258: 113488, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31859123

RESUMO

The townships of Puchuncaví and Quintero, on the coast of central Chile, have soils contaminated by atmospheric deposition of sulfur dioxide and trace elements from the nearby Ventanas Industrial Complex. The purpose of this study was to evaluate potential human health and ecological risks, by determining the spatial distribution of soil total concentrations arsenic (As), copper (Cu), lead (Pb), and zinc (Zn) in these townships. Total concentrations of these elements were determined in 245 topsoil samples, used to generate continuous distribution maps. The background concentrations of Cu, As, Pb, and Zn in the studied soils were 100, 16, 35, and 122 mg kg-1, respectively. The concentrations of Cu, As, and Pb were positively correlated with each other, suggesting that their source is the Ventanas copper smelter. On the other hand, correlations for Zn were weaker than for other trace elements, suggesting low impact of the Ventanas copper smelter on spatial distribution of Zn. Indeed, only 6% of the study area exhibited Zn concentrations above the background level. In contrast, 77, 32 and 35% of the study area presented Cu, As, and Pb concentrations, respectively, above the background level. The carcinogenic risk due to exposure to As was above the threshold value of 10-04 in the population of young children (1-5 years old) on 27% of the study area. These risk values are classified as unacceptable, which require specific intervention by the Chilean government. Based on the estimated concentrations of exchangeable Cu, 10, 15, and 75% of the study area exhibited high, medium, and low phytotoxicity risk, respectively.


Assuntos
Poluentes Atmosféricos/análise , Arsênico/análise , Cobre/análise , Exposição Ambiental/análise , Chumbo/análise , Medição de Risco/métodos , Poluentes do Solo/análise , Solo/química , Zinco/análise , Arsênico/toxicidade , Criança , Pré-Escolar , Chile , Cobre/toxicidade , Exposição Ambiental/efeitos adversos , Monitoramento Ambiental/métodos , Humanos , Indústrias , Lactente , Chumbo/toxicidade , Metais Pesados , Análise Espacial , Zinco/toxicidade
9.
Aquat Toxicol ; 217: 105338, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31711008

RESUMO

Oxidative stress parameters were evaluated during the first 72 h of embryonic development of purple sea urchin Strongylocentrotus purpuratus continuously exposed to control conditions, to cadmium alone (Cd, 30 µg/L), to zinc alone (Zn, 9 µg/L) or to a Cd (28 µg/L) plus Zn (9 µg/L) mixture. These sublethal concentrations represent ∼ 10% of the acute EC50. Bioaccumulation, antioxidant capacity against peroxyl radicals (ACAP), total glutathione (GSH) level, glutathione-S-transferase (GST), glucose-6-phosphate dehydrogenase (G6PDH) and superoxide dismutase (SOD) activity, and lipid peroxidation (LPO) were analyzed at 24 h (blastula), 48 h (gastrula), and 72 h (pluteus) stages of development. Zinc (an essential metal) was well-regulated, whereas Cd (non-essential) bioaccumulated and whole-body [Cd] increased from blastula to pluteus stage in sea urchin larvae. In controls, ACAP progressively declined from 24 h to 72 h, while LPO reciprocally increased, but other parameters did not change. Cd alone was more potent than Zn alone as a pro-oxidant, with the major effects being decreases in SOD activity and parallel increases in LPO throughout development; GST activity also increased at 24 h. Zn alone caused only biphasic disturbances of ACAP. In all cases, the simultaneous presence of the other metal prevented the effects, and there was no instance where the oxidative stress response in the presence of the Cd/Zn mixture was greater than in the presence of either Cd or Zn alone. Therefore the sublethal effects of joint exposures were always less than additive or even protective, in agreement with classical toxicity data. Furthermore, our results indicate that SOD and Zn can play important roles in protecting sea urchin embryos against Cd-induced lipid peroxidation.


Assuntos
Antioxidantes/metabolismo , Cádmio/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Strongylocentrotus purpuratus/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Zinco/toxicidade , Animais , Cádmio/análise , Glutationa/metabolismo , Glutationa Transferase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Strongylocentrotus purpuratus/crescimento & desenvolvimento , Strongylocentrotus purpuratus/metabolismo , Poluentes Químicos da Água/análise , Zinco/análise
10.
Environ Sci Pollut Res Int ; 26(34): 35107-35120, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31679142

RESUMO

In freshwater ecosystem, phototrophic biofilms play a crucial role through adsorption and sequestration of organic and inorganic pollutants. However, extracellular polymeric substance (EPS) secretion by phototrophic biofilms exposed to metals is poorly documented. This work evaluated the physiological responses of phototrophic biofilms by exposing three microorganisms (cyanobacterium Phormidium autumnale, diatom Nitzschia palea and green alga Uronema confervicolum) to 20 and 200 µg L-1 of Cu or 60 and 600 µg L-1 of Zn, both individually and in combination. Analysis of metal effects on algal biomass and photosynthetic efficiency showed that metals were toxic at higher concentrations for these two parameters together and that all the strains were more sensitive to Cu than to Zn. U. confervicolum was the most impacted in terms of growth, while P. autumnale was the most impacted in terms of photosynthetic efficiency. In consequence to metal exposure at higher concentrations (Cu200, Zn600 and Cu200Zn600), a higher EPS production was measured in diatom and cyanobacterium biofilms, essentially caused by an overproduction of protein-like polymers. On the other hand, the amount of secreted polysaccharides decreased during metal exposure of the diatom and green alga biofilms. Size exclusion chromatography revealed specific EPS molecular fingerprints in P. autumnale and N. palea biofilms that have secreted different protein-like polymers during their development in the presence of Zn600. These proteins were not detected in the presence of Cu200 despite an increase of proteins in the EPS extracts compared to the control. These results highlight interesting divergent responses between the three mono-species biofilms and suggest that increasing protein production in EPS biofilms may be a fingerprint of natural biofilm against metal pollutants in freshwater rivers.


Assuntos
Biofilmes/crescimento & desenvolvimento , Cobre/toxicidade , Zinco/toxicidade , Biofilmes/efeitos dos fármacos , Biomassa , Cobre/análise , Cianobactérias/metabolismo , Diatomáceas/metabolismo , Ecossistema , Matriz Extracelular de Substâncias Poliméricas , Água Doce , Metais/análise , Fotossíntese , Rios , Zinco/análise
11.
Environ Sci Pollut Res Int ; 26(36): 36820-36831, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31745774

RESUMO

The adverse effects of heavy metals, such as cadmium, zinc, and copper, occur due to the generation of reactive oxygen species (ROS). The use of Caenorhabditis elegans for the purposes of conservation and biomonitoring is of great interest. In the present study, ROS, malondialdehyde (MDA), and citric acid levels and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities in a model organism were tested to study toxicity. C. elegans was exposed to three different concentrations of cadmium (CdCl2, 5, 10, 50 µM), zinc (ZnSO4, 10, 100, 500 µM), and copper (CuSO4, 10, 100, 500 µM) for 3 days. ROS levels increased by 1.3- to 2.1-fold with increasing metal concentrations. The MDA content increased by approximately 7-, 5-, 2-fold after exposure to high concentrations of cadmium, zinc, and copper, respectively. Furthermore, the citric acid content increased by approximately 3-fold in the cadmium (Cd, 5 µM), zinc (Zn, 10 µM), and copper (Cu, 100 µM) treatment groups compared to that in untreated C. elegans. Therefore, citric acid may play an important role in heavy metal detoxification. Excess citric acid also slightly increased the LC50 by 1.3- to 2.0-fold, basic movements by 1.0- to 1.5-fold, decreased the ROS content by 2.4- to 2.1-fold, the MDA content by 4- to 2-fold, the SOD activity by 9- to 3-fold, the GPx activity by 4.0- to 3.0-fold, and the mRNA expression levels of GPxs by 3.2- to 1.8-fold after metals treatment. And it is most significantly in the alleviation of citric acid to cadmium. This study not only provides information to further understand the effects of heavy metal exposure on ROS, MDA, GPx, SOD, and citric acid in worms but also indicates that supplemental citric acid can protect animals from heavy metal stress and has broad application prospects in decreasing oxidative damage caused by heavy metals.


Assuntos
Antioxidantes/metabolismo , Caenorhabditis elegans/fisiologia , Ácido Cítrico/metabolismo , Metais Pesados/toxicidade , Animais , Cádmio/toxicidade , Caenorhabditis elegans/efeitos dos fármacos , Cobre/toxicidade , Malondialdeído/metabolismo , Oxirredução , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo , Zinco/toxicidade
12.
Environ Sci Pollut Res Int ; 26(32): 33541-33554, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31583521

RESUMO

Lead and zinc are usually found at the same occupational places and occur as co-contaminants. Effects of lead toxicity are detrimental on human health as it is probable carcinogen and impairs normal growth and development. On the other hand, zinc is an important nutritional element, the deficiency of which causes debilitating effects on growth and development. The purpose of this study was to examine the possible association of blood lead and zinc levels and any influence of zinc over DNA damage, blood cell membrane aberration and oxidative stress among lead and zinc co-exposed workers. Atomic absorption spectroscopy was used for lead and zinc measurement and comet assay for DNA damage assessment. Haematological aberrations were studied using light and electron microscopy (LM and EM) followed by electron density X-ray spectroscopy (EDS) and elemental mapping. Occupational exposure was observed to cause significant elevation in blood lead levels among workers. This elevation in lead levels and associated DNA damage among workers was significantly high in comparison to controls. Further light and electron micrographs of red blood cells revealed significant morphological alterations associated with increased lead ions in workers. It was clear from SEM-based elemental maps and EDS graphs that elevated lead levels were associated with low levels of zinc. The results suggest that lead absorption is highly influenced due to zinc levels in body which has an impact over DNA damage, blood cell aberration and oxidative stress caused by lead exposure. Efforts are going on to understand the role of other trace metals on lead toxicity in order to develop a sustainably nutrition-based therapeutic intervention. Graphical abstract.


Assuntos
Chumbo/toxicidade , Exposição Ocupacional/análise , Zinco/toxicidade , Adulto , Ensaio Cometa , Dano ao DNA , Eritrócitos , Humanos , Chumbo/metabolismo , Intoxicação por Chumbo , Masculino , Estresse Oxidativo/efeitos dos fármacos , Espectrofotometria Atômica , Oligoelementos/farmacologia , Zinco/metabolismo
13.
Bull Environ Contam Toxicol ; 103(6): 802-807, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31587082

RESUMO

In this work, we assessed the toxic effects of ZnO nanoparticles (NPs; 1, 10, and 50 mg L-1) and the corresponding dissoluble Zn ions (0.71, 8.66, and 35.59 mg L-1) on Microcystis aeruginosa. After chronic exposure (28 days), significantly higher growth inhibition was observed under ZnO NPs at 1 mg L-1 (47%) than under Zn ions at 0.71 mg L-1 (-15%). The opposite effect pattern was observed for ZnO NPs at 10 (71% vs. 80%) and 50 mg L-1 (73% vs. 95%) compared to Zn ions at the corresponding concentrations. After 7 days of exposure, ZnO NPs at 10 and 50 mg L-1 led to an increase of 83 and 53% in malondialdehyde content, as well as an increase of 106 and 61% in superoxide dismutase activity, respectively. However, Zn ions at the corresponding concentrations showed negligible impacts on the two parameters. The different results indicate that the insoluble NPs during the initial exposure mostly account for lipid peroxidation, which further lead to microalgal antioxidant response. During the subsequent exposure, the contributors of ZnO NP toxicity shift with the concentration and exposure time of ZnO NPs. In conclusion, the study presents new insights into the different contributions of insoluble NPs and dissoluble metallic ions to metallic NP toxicity.


Assuntos
Nanopartículas Metálicas/toxicidade , Microcystis/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Óxido de Zinco/toxicidade , Zinco/toxicidade , Antioxidantes/metabolismo , Relação Dose-Resposta a Droga , Íons , Peroxidação de Lipídeos/efeitos dos fármacos , Malondialdeído/metabolismo , Microcystis/metabolismo
14.
Ecotoxicol Environ Saf ; 185: 109677, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31563747

RESUMO

The aim of this study was to develop a new method, using a vibration sensor, to address the drawbacks of preexisting methods for monitoring soil ecological toxicity. A novel method was designed by inspiration from seismometers, which record signals originating from the ground motion caused by earthquake events. Similarly, the newly developed method using a vibration sensor detects the signals generated by earthworm activity, which reflects the soil ecological toxicity. To establish the new method, a stepwise approach was adopted: (1) the effects of operational conditions on the overall performance of the system were evaluated, and (2) the feasibility of the method was tested by an application study. A number of crucial factors influencing the overall performance of the method were evaluated. These were categorized based on three features: soil, tested organism, and instrumentation. The soil properties evaluated included soil type (artificial and natural), moisture content, and bulk density. In terms of the organism, the effect of the number of earthworms was investigated. Finally, with regard to instrumentation, appropriate soil chamber specifications and monitoring duration were identified. The most effective conditions for each factor were determined based on a comparative evaluation of changes in the activity levels and body weights of the earthworms. After the first step of the study, an application study was carried out to demonstrate the feasibility of the proposed method. Zinc (Zn)-contaminated soils were tested under the most efficient operational conditions identified in the preceding study. The results of the study confirm that the method is applicable to natural soils, and the best performance was achieved under soil conditions of 50-60% maximum water holding capacity and 0.95 g/cm3 bulk density. Furthermore, the optimal number of earthworms was found to be five, which corresponds 19.84 g soil per earthworm. With respect to the instrumental conditions, the most efficient specification was a cylindrical soil chamber with a diameter of 94 mm and height of 54 mm. Additionally, the most relevant monitoring duration was found to be 7 days. The results indicate that the method can shorten the testing period, reduce the soil amount and earthworm number required, and facilitate the real-time monitoring of mortality. Based on the results of the application study, we validated the proposed vibration sensor-based method for characterizing earthworm behavior in terms of its feasibility for monitoring the ecological toxicity of soil. The results indicate that dermal contact and feeding activity of earthworms decreased significantly with increasing Zn concentrations in the soil. The EC50 value of Zn calculated based on the earthworm behavior was 340.97 mg/kg. Based on the results, it is concluded that the proposed method cannot only overcome the shortcomings of traditional test methods using earthworms, but also enable real-time ecotoxicity in soil environments.


Assuntos
Monitoramento Ambiental , Locomoção/efeitos dos fármacos , Oligoquetos/efeitos dos fármacos , Poluentes do Solo/toxicidade , Solo/química , Animais , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos , Poluentes do Solo/análise , Fatores de Tempo , Vibração , Zinco/análise , Zinco/toxicidade
15.
Plant Sci ; 287: 110201, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31481218

RESUMO

Nowadays, Zinc (Zn) deficiency is the most widespread micronutrient deficiency but simultaneously Zn toxicity is produced due to environmental pollution. A potential method to alleviate Zn deficiency and to reduce Zn concentration in soils is through the generation of plants with enhanced capacity for Zn accumulation and higher tolerance. This could be achieved through the modification of HMA4 transporter. BraA.hma4a-3 is a TILLING mutant plant that presents one modification in HMA4 transporter. Thus, in this study we analyzed the potential of BraA.hma4a-3 for Zn accumulation and Zn deficiency and toxicity tolerance. BraA.hma4a-3 and parental R-o-18 plants were grown with different Zn doses: 1 µM ZnSO4 (Control), 0.01 µM ZnSO4 (Zn deficiency) and 100 µM ZnSO4 (Zn toxicity). Parameters of biomass, Zn concentration, photosynthesis, oxidative stress, N metabolism and amino acids (AAs) were measured. BraA.hma4a-3 did not affect plant biomass but did increase Zn accumulation in leaves under an adequate Zn supply and Fe under control and Zn deficiency doses. Regarding stress tolerance parameters and N metabolism, BraA.hma4a did not produce alterations under control conditions. In addition, under Zn toxicity, parameters suggest a greater tolerance. Briefly, the obtained results point to BraA.hma4a-3 as a useful mutant to increase Zn accumulation.


Assuntos
Brassica rapa/fisiologia , Nitrogênio/metabolismo , Zinco/metabolismo , Aminoácidos/metabolismo , Biodegradação Ambiental , Biofortificação , Biomassa , Brassica rapa/genética , Brassica rapa/crescimento & desenvolvimento , Mutação , Estresse Oxidativo , Fotossíntese , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Solo/química , Zinco/deficiência , Zinco/toxicidade
16.
Bull Environ Contam Toxicol ; 103(4): 636-641, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31473776

RESUMO

Livestock and poultry manure containing high levels of copper and zinc have led to contamination of farmland and products which could have an impact on human health. Biochar is an inexpensive and efficient heavy metal absorbent. In the present study, we have used biochar to mitigate the effects of heavy metals on the growth of wheat seedlings. The study showed that the effects of heavy metals on wheat seedlings growth were mitigated by increasing exposure to biochar. Compared to the control group, the germination potential, germination rate, germination index and vigor index of wheat seedlings with supplemented biochar increased significantly. Moreover, the specific activity of catalase, peroxidase, superoxide dismutase decreased and chlorophyll contents increased, which promote wheat growth and suggests that the addition of biochar could reduce the effects of heavy metals on wheat seedlings.


Assuntos
Carvão Vegetal/química , Cobre/toxicidade , Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/toxicidade , Triticum/fisiologia , Zinco/toxicidade , Catalase , Clorofila , Grão Comestível/química , Germinação , Esterco , Metais Pesados/análise , Oryza , Plântula/efeitos dos fármacos , Solo , Poluentes do Solo/análise , Triticum/efeitos dos fármacos , Triticum/enzimologia
17.
Artigo em Inglês | MEDLINE | ID: mdl-31491979

RESUMO

Vegetable contamination in mining and smelting areas has resulted in high dietary intakes of heavy metals, which pose potential health risks to local residents. In this study, paired soil-vegetable samples were collected around Pb/Zn smelters in Southwest China. Probabilistic risks to local residents via vegetable consumption were evaluated with a Monte Carlo simulation. The mean concentrations of As, Cd, Cu, Pb, and Zn in the soils were 116.76, 3.59, 158.56, 196.96, and 236.74 mg/kg, respectively. About 38.18%, 58.49%, and 52.83% of the vegetable samples exceeded the maximum allowable concentrations for As, Cd, and Pb, respectively. The daily dietary intake of As, Cd, and Pb exceeded the provisional tolerable daily intakes for local residents, with children showing the highest intake via vegetable consumption. The percentages of the target hazard quotients of As, Cd, and Pb for local residents exceeding the safe value of one were about 95%, 50%, and 25%, respectively. The 95th percentiles of the hazard index for children, adolescents, and adults were 15.71, 11.15, and 9.34, respectively, indicating significant risks to local residents, especially children. These results highlight a need to develop effective strategies to reduce heavy metal contamination and exposure to protect human health.


Assuntos
Chumbo/análise , Metais Pesados/toxicidade , Probabilidade , Medição de Risco , Poluentes do Solo/toxicidade , Verduras/química , Zinco/análise , Adolescente , Adulto , Criança , Pré-Escolar , China , Humanos , Chumbo/toxicidade , Pessoa de Meia-Idade , Mineração , Adulto Jovem , Zinco/toxicidade
18.
Microsc Res Tech ; 82(12): 2014-2025, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31471999

RESUMO

To estimate trace element bioaccumulation in Armadillo officinalis, specimens were collected from Ghar El Melh lagoon then exposed for 3 weeks in contaminated sediments with copper, zinc, and cadmium. From the first week until the end of the experiment, a decrease in A. officinalis growth related to the increase of Cd concentration in the sediment was recorded. However, a mass gain was highlighted under Cu and Zn exposures. At the end of experiment, body metal concentrations were measured using flame atomic emission spectrometry. Results of the bioaccumulation factor showed that the species could be considered as a macroconcentrator of copper (BAF > 2) and a deconcentrator of zinc (BAF < 2). Microscopy observations of hepatopancreas cells showed morphological and histological changes even at the lowest concentration. They consisted in the microvillus border destruction, lipid droplets modifications, trace element accumulation, and the condensation of the majority of cellular organelles. The degree of these alterations was found to be dose-dependent. Through these results, the isopod A. officinalis could be used as relevant monitor organisms for soil metal contamination.


Assuntos
Bioacumulação , Cádmio/farmacocinética , Cobre/farmacocinética , Isópodes/química , Oligoelementos/análise , Zinco/farmacocinética , Animais , Cádmio/toxicidade , Cobre/toxicidade , Poluição Ambiental/análise , Sedimentos Geológicos/química , Hepatopâncreas/química , Hepatopâncreas/citologia , Isópodes/ultraestrutura , Tunísia , Zinco/toxicidade
19.
Chemosphere ; 237: 124501, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31398612

RESUMO

Several evidences from the literature showed that the coexistence of nickel and zinc in polluted waters is related to the similarity in their geogenic and anthropogenic factors. Although most environmental exposures to metals do not occur singly, there is a paucity of scientific knowledge on the effects of zinc and nickel co-exposure on mammalian reproductive health. The present study investigated the influence of co-exposure to nickel and zinc on male reproductive function in rats. Experimental rats were co-exposed to environmentally relevant concentrations of waterborne nickel (75 and 150 µg NiCl2 L-1) and zinc (100 and 200 µg ZnCl2 L-1) for 45 successive days. Subsequently, reproductive hormones were assayed whereas the hypothalamus, epididymis and testes of the rats were processed for the assessment of oxidative stress and inflammation indices, caspase-3 activity and histology. Results indicated that co-exposure to nickel and zinc significantly (p < 0.05) abolished nickel-mediated diminution of antioxidant defense mechanisms while diminishing levels of reactive oxygen and nitrogen species and lipid peroxidation in the hypothalamus, epididymis and testes of the exposed rats. Additionally, co-exposure to zinc abated nickel-mediated diminutions in luteinizing hormone, follicle-stimulating hormone, serum and intra-testicular testosterone with concomitant enhancement of sperm production and quality. Further, zinc abrogated nickel-mediated elevation in inflammatory biomarkers including nitric oxide, tumor necrosis factor alpha, interleukin-1 beta as well as caspase-3 activity. The protective influence of zinc on nicked-induced reproductive toxicity was well supported by histological data. Overall, zinc ameliorated nickel-induced reproductive dysfunction via its anti-oxidant, anti-inflammatory, anti-apoptotic and spermato-protective activities in rats.


Assuntos
Níquel/toxicidade , Poluentes Químicos da Água/toxicidade , Zinco/toxicidade , Animais , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Epididimo/efeitos dos fármacos , Hormônio Foliculoestimulante/sangue , Peroxidação de Lipídeos/efeitos dos fármacos , Hormônio Luteinizante/sangue , Masculino , Oxidantes/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Wistar , Reprodução/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos , Testículo/efeitos dos fármacos , Testosterona/sangue
20.
Mar Pollut Bull ; 149: 110493, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31442865

RESUMO

Melanisation of muscle, observed as black pigmentation of the normally white flesh, has been reported in sand flathead from Tasmania and investigated in this study. There was a significant difference in the presence of melanised muscle in sand flathead from two sites within the Tamar Estuary (northern Tasmania), with higher proportion of sand flathead from Deceitful Cove with this condition. Presence of melanisation was not related to length or weight of the fish. No parasitic infections were detected in the muscles of the affected sand flathead. However, concentration of zinc in melanised regions of muscle in the affected fish was significantly higher, about 1.7 to 1.8 times, than non-melanised regions of muscle in the same fish. Furthermore, the concentration of zinc in melanised regions of affected fish was on average about 2.0 times higher when compared to muscle of unaffected fish that had no melanised spots.


Assuntos
Músculos , Perciformes , Zinco , Animais , Estuários , Músculos/química , Areia , Tasmânia , Poluentes Químicos da Água/análise , Zinco/toxicidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA