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1.
Environ Pollut ; 265(Pt B): 114993, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32806449

RESUMO

Among the most used non-steroidal anti-inflammatory drugs (NSAIDs), ketoprofen (KTF) assumes an important position. Nevertheless, its ecotoxicological effects in non-target organisms are poorly characterized, despite its use and frequency of occurrence in aquatic matrices. Thus, the aim of this study was to evaluate the possible toxicological effects of KTF contamination, in two freshwater species, Lemna minor and Daphnia magna, by measuring biochemical, physiological and population parameters. To attain this objective, both species were exposed to KTF at the same concentrations (0, 0.24, 1.2, 6 and 30 µg/L). L. minor plants were exposed during 4 d to these levels of KTF, and the enzymatic activity (catalase (CAT), glutathione S-transferases (GSTs) and carbonic anhydrase (CA)), and pigments content (chlorophylls a, b and total and carotenoids) were analyzed to evaluate the toxicity of this drug. D. magna was acutely and chronically exposed to KTF, and enzymatic activities (CAT, GSTs and cyclooxygenase (COX)), the feeding rates, and reproduction traits were assessed. In L.minor, KTF provoked alterations in all enzyme activities, however, it was not capable of causing any alteration in any pigment levels. On the other hand, KTF also provoked alterations in all enzymatic activities in D. magna, but did not affect feeding rates and life-history parameters. In conclusion, exposure to KTF, provoked biochemical alterations in both species. However, these alterations were not reflected into deleterious effects on physiological and populational traits of L. minor and D. magna.


Assuntos
Araceae , Cetoprofeno , Poluentes Químicos da Água , Animais , Daphnia , Água Doce
2.
Water Sci Technol ; 81(9): 1852-1862, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32666940

RESUMO

The kinetics of Se uptake and toxicity to Lemna were studied over a period of 14 days of exposure to Se(IV) or Se(VI). The growth of Lemna stopped immediately after exposure to 5.0 mg/L of Se(IV) or Se(VI). The content of chlorophyll and phaeopigments of Lemna exposed to 5.0 mg/L of Se(IV) was two to three times less than in the control after 3 d exposure. Lemna took up Se rapidly within the first 3 d. The Se content in Lemna along with the exposure time fitted well the two-compartment and the hyperbolic model, which demonstrates that the mechanism of Se(IV) and Se(VI) uptake in Lemna is not only through passive diffusion, but also through other processes such as ion channel proteins or transporters. The kinetic bioconcentration factors (BCFs) were 231 and 42 for 0.5 mg/L Se(IV) and Se(VI) exposure, respectively. The uptake rate of Lemna reached 263 mg/kg/d and 28 mg/kg/d in the Se(IV) and Se(VI) treatments, respectively. This study showed that Se(IV) has a faster accumulation rate than Se(VI), but a higher toxicity, indicating Lemna could be a good candidate to remove Se(IV) from water, producing Se-enriched biomass which may eventually also be considered for use as Se-enriched feed supplement or fertilizer.


Assuntos
Araceae , Selênio , Biomassa , Fertilizantes , Ácido Selênico , Ácido Selenioso
3.
Chemosphere ; 259: 127407, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32593821

RESUMO

The objective of this study was to investigate the impact of two pharmaceuticals, diclofenac and sulfamethoxazole, and their binary mixture on aquatic organisms, marine bacteria Aliivibrio fischeri, crustacean Daphnia magna, and vascular plant Lemna minor. The binary mixture of the drugs showed the highest toxicity towards the model organisms. Diclofenac had an average toxicity which posed a high environmental risk to aquatic organisms, while sulfamethoxazole was characterized by a low toxicity with low environmental risk. The organism most sensitive to diclofenac was A. fischeri (IC50 = 8.72 ± 1.14 mg L-1) and for sulfamethoxazole and the binary mixture, it was L. minor (IC50 = 12.56 ± 4.48 and 4.83 ± 0.43 mg L-1, respectively). The toxicity of the mixture was predicted using the Concentration Addition and Independent Action models, and the results were compared with the experimental data. None of the models suitably predicted the real toxicity of the pharmaceutical mixture. Interactions between the mixture components were confirmed by calculating the mixture toxicity index values which showed that the pharmaceuticals displayed synergistic or partial additive effects which depended on the selected test organism and test duration. When added as a complex matrix to wastewater (at a concentration of 2 mg L-1 each), the pharmaceuticals did not display increased toxicity. This observation confirms that the presence of micro-contaminants in aquatic environments may cause interactions between different compounds, the results of which are difficult to predict and model.


Assuntos
Diclofenaco/toxicidade , Sulfametoxazol/toxicidade , Poluentes Químicos da Água/toxicidade , Aliivibrio fischeri/efeitos dos fármacos , Animais , Organismos Aquáticos , Araceae/efeitos dos fármacos , Daphnia/efeitos dos fármacos , Águas Residuárias , Poluentes Químicos da Água/análise
4.
Aquat Toxicol ; 225: 105550, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32593114

RESUMO

Plant diversity has important functions in ecosystem productivity overyielding and community stability. Little is known about the mechanism causing productivity overyielding and stability under harsh conditions. This study investigated the photosynthetic response and subcellular distribution of uni- and co-cultured duckweeds (Lemna aequinoctialis and Spirodela polyrhiza) under excess copper (1.0 mg/L) and low temperature (5 °C) conditions. The results showed that the growth of uni-cultured L. aequinoctialis was not different from that of uni-cultured S. polyrhiza across copper treatments at control temperature (25 °C). The growth rate of L. aequinoctialis increased by 55.5 % under excess copper concentration when it coexisted with S. polyrhiza, compared with uni-culture. Subcellular distributions of copper were predominantly distributed in cell walls. S. polyrhiza accumulated more copper in cell walls than L. aequinoctialis under uni-cultured condintion at excess copper concentration. Co-cultured S. polyrhiza increased copper accumulation in cell walls of co-cultured L. aequinoctialis to decrease toxicity at excess copper concentration, compared with L. aequinoctialis. Low temperature increased copper toxicity, with duckweeds having lower growth rate and photosynthetic activities (Fv/Fm). The L. aequinoctialis growth rate in co-culture was higher than in uni-culture under excess copper concentration and low temperature conditions, indicating that S. polyrhiza decreased the copper toxicity for L. aequinoctialis. The photosynthetic activity (Fv/Fm) of co-cultured L. aequinoctialis was higher than that of uni-cultured L. aequinoctialis exposed to excess copper concentration at low temperature. The community that formed by co-culturing S. polyrhiza and L. aequinoctialis produced more biomass by avoiding the toxicity of excess copper through heavy metal compartmentalization and photosynthetic activities.


Assuntos
Resposta ao Choque Frio/fisiologia , Metais Pesados/metabolismo , Poluentes Químicos da Água/toxicidade , Araceae/crescimento & desenvolvimento , Araceae/fisiologia , Biomassa , Cobre/toxicidade , Ecossistema , Metais Pesados/toxicidade , Fotossíntese
5.
Ying Yong Sheng Tai Xue Bao ; 31(2): 608-614, 2020 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-32476355

RESUMO

To solve the yellow colorization in water caused by iron ion, we evaluated the remediation performances of six aquatic plant species (Hygroryza aristata, Myriophyllum verticillatum, Hydrocotyle verticillata, Jussiaea stipulacea, Pistia stratiotes and Rotala rotundifolia) using hydroponic experiment. Effects of iron concentration, pH, plant biomass on iron removal were investigated, and the intensification of removing iron incurred by aeration was also discussed. Results showed that all the examined plant species could improve both divalent iron and total iron removal, but with significant difference in their performance. Divalent iron concentrations were decreased by H. aristata and H. verticillata from 5.0 mg·L-1 to 0.23 and 0.26 mg·L-1 within 24 h, respectively, meeting the standard of supplementary items for the drinking water and surface water sources (divalent iron concentration ≤0.3 mg·L-1), while total iron concentrations declined to 0.84 and 1.21 mg·L-1 with removal efficiency of 83.2% and 75.8%, respectively. Concentrations of divalent iron and total iron of plant treatment plots at pH 5, 6, 7, 8 were not significantly different, with removal efficiency of divalent iron and total iron being among 95.4%-98.4% and 92.2%-94.6%, separately. When initial divalent iron concentration was less than 5.0 mg·L-1, removal efficiency of divalent iron and total iron increased with the increases of divalent iron concentration. The growth of H. aristata was inhibited at divalent iron concentration of 10.0 mg·L-1. Total iron removal was not stable during the trial. Removal efficiency of plant treatment rose only by 7.0% compared with the control, which was much lower than other concentration treatments. The divalent iron concentration was decreased to < 0.3 mg·L-1 in 24 h at plant biomass :300 g, with no difference of removal efficiency among biomass treatments. Both intermittent and continuous aeration enhanced iron removal by H. aristata, but continuous aeration was more favorable for the removal of total iron due to stabilization.


Assuntos
Araceae , Poluentes Químicos da Água , Purificação da Água , Biodegradação Ambiental , Ferro , Água
6.
Sci Total Environ ; 739: 139715, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32534307

RESUMO

Salicylic acid (SA) is a pharmaceutical drug that may exert toxic effects by its own; however, simultaneous exposure of plants to SA and to other substances, often results in the significant changes in the patterns of toxic response/resistance to these other sources of chemical stress. Thus, the aim of this work was to investigate the capacity of SA of modulating Lemna minor responses co-exposed to the pharmaceutical drug, diclofenac - DCF. To attain this objective, L. minor was exposed for 7 days, to DCF alone, and to combinations of DCF with SA. After exposure, biochemical, physiological and population endpoints were analyzed as follows: catalase (CAT) and glutathione S-transferases (GSTs) activities, pigments content (chlorophyll a (Chl a), b (Chl b) and total (TChl), carotenoids (Car) and [Chl a]/[Chl b] and [TChl]/[Car] ratios), and growth specific rate, fresh weight and root length. Single exposures to DCF were capable of causing effects in all analyzed endpoints. However, co-exposure of DCF with SA partially reverted these effects. Finally, we may suggest that SA is capable to prevent the toxicity of DCF in macrophytes, by modulating the toxic response of exposed plants.


Assuntos
Araceae , Poluentes Químicos da Água , Antioxidantes , Clorofila , Clorofila A , Diclofenaco , Ácido Salicílico
7.
Environ Sci Pollut Res Int ; 27(21): 26103-26114, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32358747

RESUMO

The intensive development of medical science has led to an increase in the availability and use of pharmaceutical products. However, nowadays, most of scientific attention has been paid to the native forms of pharmaceuticals, while the transformation products (TPs) of these substances, understood herein as metabolites, degradation products, and selected enantiomers, remain largely unexplored in terms of their characterization, presence, fate and effects within the natural environment. Therefore, the main aim of this study was to evaluate the toxicity of seven native compounds belonging to different therapeutic groups (non-steroidal anti-inflammatory drugs, opioid analgesics, beta-blockers, antibacterial and anti-epileptic drugs), along with the toxicity of their 13 most important TPs. For this purpose, an ecotoxicological test battery, consisting of five organisms of different biological organization was used. The obtained data shows that, in general, the toxicity of TPs to the tested organisms was similar or lower compared to their parent compounds. However, for example, significantly higher toxicity of the R form of ibuprofen to algae and duckweed, as well as a higher toxicity of the R form of naproxen to luminescent bacteria, was observed, proving that the risk associated with the presence of drug TPs in the environment should not be neglected.


Assuntos
Araceae , Poluentes Químicos da Água/análise , Anti-Inflamatórios não Esteroides , Ecotoxicologia , Ibuprofeno , Naproxeno
8.
Ecotoxicology ; 29(5): 571-583, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32342293

RESUMO

In the present study, single and mixture effects of cadmium (Cd) and zinc (Zn) on Lemna gibba were analyzed and compared using growth parameters, based on frond number and fresh weight, and biochemical parameters, such as pigment, protein content and activity of antioxidant enzymes. Plants were exposed for 7 days to these metals in nutrient solution. Single and mixture exposures affected plant growth and the biomarkers of the antioxidant response. Considering the growth parameters, Cd was found to be much more toxic than Zn. IC50-7d, based on growth rate calculated on frond number, were 17.8 and 76.73 mg/L, and on fresh weight were 1.08 and 76.93 mg/L, for Cd and Zn respectively. For Cd, LOEC values were obtained at 2.06 and 1.03 mg/L, for frond number and fresh weight respectively; while for Zn, at 20.1 and 74.6 mg/L. A high toxicity effect, considering the same response variables, was observed in plants exposed to the mixtures. Three fixed ratios, based on toxic units (TU) were assayed, ratio 1: 2/3 Cd-1/3 Zn, ratio 2: 1/2 Cd-1/2 Zn and ratio 3: 1/3 Cd-2/3 Zn. Ratio 3 (where Zn was added in higher proportion) was the less toxic. All concentrations of Ratio 1 and 2 significantly inhibited plant growth, showing a 100% inhibition of growth rate at the highest concentrations when based on frond number. Catalase (CAT; EC 1.11.1.6), ascorbate peroxidase (APOX; EC 1.11.1.11) and guaiacol peroxidase (GPOX; EC 1.11.1.7) activities in single metals assays were higher than controls. In mixture tests, the activity of APOX and GPOX was significantly stimulated in plants exposed to all evaluated combinations, while CAT was mainly stimulated in Ratio 3. It was observed that the activity of the enzymes was increased in the mixtures compared with similar concentrations evaluated individually. APOX activity was observed to fit the CA model and following a concentration-response pattern. The response of this antioxidant enzyme could serve as a sensitive stressor biomarker for Cd-Zn interactions. Frond number in Cd-Zn mixtures was not well predicted from dissolved metal concentration in solution using concentration addition (CA) as reference model, as results showed that toxicity was more than additive, with an average of ΣTU = 0.75. This synergistic effect was observed up to 50 mg Zn/L in the mixture, but when it was present in higher concentrations a less than additive effect was observed, indicating a protective effect of Zn. A synergistic and dose-ratio deviations from CA model were also observed.


Assuntos
Araceae/fisiologia , Cádmio/toxicidade , Poluentes Químicos da Água/toxicidade , Zinco/toxicidade , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Catalase/metabolismo , Peroxidase/metabolismo
9.
Environ Sci Pollut Res Int ; 27(18): 22735-22748, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32323236

RESUMO

In this research, several biochemical variations in plant of Lemna minor L. were investigated to reflect Ag+ toxicity. Lemna minor L. changed colorless AgNO3 to colloidal brown at doses equal to and greater than 1 mg L-1. Optical and fluorescence microscopy revealed the presence of bright spots in roots of tested plant related to Ag/Ag2O-NPs. Photosynthetic pigment contents of Lemna minor L. declined upon exposure to Ag+ with an evidently higher decrease in chlorophyll a than in chlorophyll b. Similarly, Ag+ treatment caused an evident reduction in the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). The reduction in antioxidase activity was significantly higher in POD than in SOD and CAT. Ag+ treatment resulted in a significant increment in the level of malondialdehyde (MDA) content as the judging criteria of cellular injury which showed sign of dose-related. The alterations occurred in RAPD profiles of treated samples following Ag+ toxicity containing loss of normal bands, appearance of new bands, and variation in band intensities compared with the normal plants. In addition, morphological character and biomass of Lemna minor L. subjected to increasing Ag+ concentrations were evaluated to reveal Ag+ toxicity. Our study demonstrated that Lemna minor L. have a high sensitivity to indicate fluctuation of water quality. It would be beneficial that modulating the genotype of Lemna minor L. to bear high proportion of contaminates.


Assuntos
Araceae , Prata , Clorofila , Clorofila A , Biomarcadores Ambientais , Técnica de Amplificação ao Acaso de DNA Polimórfico , Superóxido Dismutase
10.
PLoS One ; 15(4): e0231652, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32298342

RESUMO

Lemna species have been used in the food, feed, and pharmaceutical industries, as they are inexpensive sources of proteins, starches, and fatty acids. In this study, we treated L. paucicostata with different concentrations (0.05, 0.1, 0.2, 0.5, or 1 mM) of ethephon. The total dry weight decreased in all ethephon-treated groups compared to the control group. We also investigated the alteration of metabolic profiles induced by ethephon treatment by using gas chromatography-mass spectrometry. This analysis identified 48 metabolites, and the relative levels of most of alcohols, amino acids, fatty acids, and phenols increased by the ethephon treatment, whereas levels of organic acids and sugars decreased. Among these, the highest production of γ-aminobutyric acid (GABA, 5.041 ± 1.373 mg/L) and ferulic acid (0.640 ± 0.071 mg/L) was observed in the 0.5 mM and the 0.2 mM ethephon treatment groups, respectively. These results could be useful for large-scale culture of L. paucicostata with enhanced GABA and ferulic acid content for utilization in the food, feed, cosmetic, and pharmaceutical industries.


Assuntos
Araceae/crescimento & desenvolvimento , Ácidos Cumáricos/metabolismo , Compostos Organofosforados/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Ácido gama-Aminobutírico/metabolismo , Araceae/metabolismo , Metaboloma
11.
Chemosphere ; 254: 126752, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32335436

RESUMO

In the literature, there is a lack of data on the effect of gentian violet (GV) and congo red (CR) dyes on the biosynthesis pathway of biogenic amines (BAs) in Lemna minor L. (common duckweed). This plant species is an important link in the food chain. Both dyes inhibited growth, biomass yield and the biosynthesis of chlorophyll a in common duckweed. The predicted toxic units demonstrated that GV had a more toxic effect on the growth rate and biomass yield of common duckweed than CR. Decarboxylase activity in the biosynthesis of BAs in common duckweed is also a useful indicator for evaluating the toxicity of both dyes. Gentian violet also exerted more phytotoxic effects on the analyzed biochemical features of common duckweed because it changed the putrescine (Put) biosynthesis pathway, increased tyramine content 1.6 fold, inhibited the activity of S-adenosylmethionine decarboxylase by 40% and the activity of ornithine decarboxylase (ODC) by 80%. Tyrosine decarboxylase (TDC) was most active in plants exposed to the highest concentration of GV. Similarly to control plants, in common duckweed exposed to CR, Put was synthesized from ornithine; however, spermidine content was 86% higher, Put content was 51% lower, and ODC activity was 86% lower.


Assuntos
Araceae/fisiologia , Vermelho Congo/toxicidade , Violeta Genciana/toxicidade , Poluentes Químicos da Água/toxicidade , Araceae/efeitos dos fármacos , Aminas Biogênicas , Biomassa , Vias Biossintéticas , Clorofila A , Violeta Genciana/metabolismo
12.
Sci Total Environ ; 724: 138357, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32272417

RESUMO

Poly- and perfluoroalkyl substances (PFAS) are surfactants. Leveraging their surface active feature, this work investigated using aeration to remove perfluoroalkyl acids (PFAAs) from aqueous solutions. Eight PFAAs were spiked to either deionized water or Hoagland solution at three pHs. After 7 h of aeration, removals of perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA), perfluorobutanesulfonic acid (PFBS), and perfluorohexanoic acid (PFHxA) were marginal and much lower than those of and perfluoroheptanoic acid (PFHpA), perfluorohexanesulfonic acid (PFHxS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS). In deionized water, close to 80% of PFOA and PFOS at 200 ppb were removed when the pH was 2.3. The Hoagland solution at pH 2.3 and 5.0 benefited removal of long-chain PFAS at 2 ppb, but not at 200 ppb. With duckweed growing on the Hoagland solution surface, >95% of PFHpA, PFHxS, PFOA, and PFOS at 200 ppb were removed after 2 weeks. Aeration enhanced duckweed uptake of PFHxS, PFOA, and PFOS at 2 ppb significantly. Specific to PFOS, duckweed accumulated 14.4% of this compound initially spiked at 2 ppb in 2 weeks. These results demonstrated that aeration plus duckweed could be a viable and scalable remediation solution for surface water contaminated by PFAS.


Assuntos
Ácidos Alcanossulfônicos , Fluorcarbonetos/análise , Poluentes Químicos da Água/análise , Araceae
13.
An Acad Bras Cienc ; 92 Suppl 1: e20180519, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348414

RESUMO

Contamination of water sources due to herbicide is of great concern. Clomazone is a pesticide with a high contamination potential which could possibility lixiviate to water streams. Changes caused by residual herbicide include flora modifications which are generally detrimental for some species. The lack of morphological studies performed in aquatic plants exposed to herbicide-contaminated environments has encouraged the development of our research. For the first time, we present a study that aimed to evaluate leaf injuries visible to the naked eye as well as microscopical effects which may be caused by clomazone on Pistia stratiotes. Pistia stratiotes was subjected to five concentrations of clomazone. Our analysis showed leaf injuries, especially after 15 days of clomazone application. Hormesis was observed when the water lettuce was subjected to the lower concentrations. Total leaf area showed increase following by reduction while injured until reaching the highest concentration. Although the concentrations of clomazone tested in our study are not lethal to water lettuce, such herbicide have still caused morphoanatomical damages on leaves which advocates for the use of P. stratiotes as a bioindicator of the presence of herbicides such as clomazone in water.


Assuntos
Araceae/efeitos dos fármacos , Herbicidas/toxicidade , Isoxazóis/toxicidade , Oxazolidinonas/toxicidade , Resíduos de Praguicidas/toxicidade , Poluentes Químicos da Água/toxicidade
14.
Environ Sci Pollut Res Int ; 27(15): 17804-17814, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32162222

RESUMO

Plants can improve indoor air quality, and affect the work efficiency and subjective perceptions. However, the conclusions of existing experiments regarding how plants affect work efficiency are not uniform. To further explore this subject, this study designed five different working conditions, and selected a variety of "general tasks" and "tasks requiring concentration" as operational tasks. The effects of the plant arrangement and quantity on work efficiency were studied by analyzing the performance of subjects in different working conditions. The effects of the plants on the subjective perceptions were investigated using questionnaires. The experimental results show that the effects of plants on work efficiency were related to the nature of the work, the placement of the plants, and the number of plants. Plants had no effect on the efficiency of general tasks such as "symmetry breadth," but had a positive impact on the efficiency of general tasks such as "operational breadth." Moreover, by changing the arrangement and quantity of plants, the efficiency of general tasks could be increased by up to 19.1%. In contrast, plants placed within a coincident view had a negative impact on the efficiency of "tasks requiring concentration," and the work efficiency could be reduced by up to 12.4%. In addition, plants could increase enthusiasm and willingness to work by 12.5% and 11.8%, respectively.


Assuntos
Poluição do Ar em Ambientes Fechados , Araceae , Eficiência , Inquéritos e Questionários
15.
Chemosphere ; 251: 126366, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32145575

RESUMO

In this study, the effects of excess nickel (Ni) (100 µM and 200 µM) on growth, antioxidant production, fatty acid, organic and amino acids profiles were examined in Lemna minor L. After 7 days of Ni treatment, chlorosis, growth inhibition and ROS overproduction were observed, accompanied by Ni accumulation. Interestingly, decreased malondialdehyde (MDA) levels were recorded in fronds upon Ni exposure. Fatty acid profiles in Ni-treated L. minor were characterized by increases in saturated- and decreases in unsaturated fatty acids. Ni excess increased the activities of antioxidant enzymes such as superoxide dismutase (SOD), guiacol peroxidase (GPX), and glutathione reductase (GR), and non-enzymatic antioxidants such as glutathione (GSH) and ascorbic acid (AsA); however, deactivation of ascorbate peroxidase (APX) and catalase (CAT) activities were also observed. Disruption of amino acid metabolism in Ni-exposed fronds was evidenced by the accumulation of cysteine, arginine, threonine, valine, isoleucine, leucine, lysine and phenylalanine, as well as reduced levels of tyrosine, alanine, aspartate and proline. Approximately 299%-396%, 139%-254% and 56%-97% concentration increments in citric, malic and oxalic acids, respectively, were concomitantly observed with significant decreases in tartaric, acetic, and fumaric acids in fronds subjected to Ni stress. Taken together, these results indicated that Ni stress induced negative effects on plant physiological, biochemical and morphological processes; however, it is likely that the coordination of metabolites and antioxidants may ameliorate the damaging effects of Ni accumulation.


Assuntos
Araceae/metabolismo , Níquel/metabolismo , Antioxidantes/metabolismo , Araceae/efeitos dos fármacos , Ascorbato Peroxidases/metabolismo , Ácido Ascórbico/farmacologia , Catalase/metabolismo , Ácidos Graxos/metabolismo , Glutationa/metabolismo , Glutationa Redutase/metabolismo , Malondialdeído/metabolismo , Oxirredução , Peroxidase/metabolismo , Peroxidases/metabolismo , Prolina/metabolismo , Superóxido Dismutase/metabolismo
16.
Ecotoxicol Environ Saf ; 194: 110361, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32126411

RESUMO

Mediterranean forests are highly susceptible to wildfires, which can cause several impacts not only within burnt areas but also on downstream aquatic ecosystems. The ashes' washout from burnt areas by surface runoff can be a diffuse source of toxic substances, such as metals, when reaching the nearby aquatic systems, and can be noxious to aquatic organisms. The present work aimed at assessing the ecotoxicological effects of post-fire contamination on two aquatic producers (the microalgae Raphidocelis subcapitata and the macrophyte Lemna minor) through in-situ bioassays, validating the obtained results with the outcomes of laboratory bioassays with surface water collected simultaneously. Four distinct sites were selected in a basin partially burnt (Ceira river basin; Coimbra district, Portugal) for bioassay deployment: one site upstream the burnt area in the Ceira river (RUS); three sites located under the influence of the burnt area, one immediately downstream of the burnt area in the Ceira river (RDS) and the other two in tributary streams within the burnt area (BS1 and BS2). The in-situ bioassays lasted for 13 days and began following the first post-fire major rain events. Results showed that the microalgae growth rate was able to distinguish the three sites within and downstream of the burnt area (BS1, BS2, RDS) from the site upstream (RUS). By contrast, the macrophytes growth rate only allowed to differentiate between the sites within the burnt area (BS1 and BS2) and those up- and downstream of the burnt area (RUS and RDS). The in-situ results for both species were corroborated with the results of the laboratory experiments, supporting the use of laboratory surrogates for a screening assessment of wildfire impacts in aquatic ecosystems. Direct causal relationships between the observed ecotoxicological effects on R. subcapitata and L. minor and the physical-chemical parameters of the water samples were difficult to establish, although the results suggest (i) a role of differential major and trace metal load in explaining species growth variation; (ii) interaction between metals and/or between metals and other field parameters are likely to modulate the biological responses to the challenges deriving from wildfire runoff.


Assuntos
Organismos Aquáticos/fisiologia , Bioensaio , Monitoramento Ambiental/métodos , Incêndios Florestais , Araceae/efeitos dos fármacos , Ecossistema , Ecotoxicologia , Fogo , Florestas , Água Doce/química , Metais/farmacologia , Portugal , Chuva , Rios/química , Oligoelementos/farmacologia
17.
Sci Total Environ ; 722: 137854, 2020 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-32197162

RESUMO

In Vietnam, swine wastewater is generally treated using anaerobic processes. Nevertheless, the level of pollutants in effluent after anaerobic treatment remains very high, thereby necessitating further treatment. This research was conducted to assess the applicability of duckweed (Lemna minor) for purifying wastewater collected from a household swine wastewater treatment system in Hanoi, Vietnam. After the anaerobically treated wastewater was diluted 10-fold, it was fed continuously to lab-scale stabilization ponds with and without planted duckweed at a hydraulic retention time of 5 days under ambient conditions. The chemical oxygen demand (COD), total nitrogen (T-N), and total phosphorus (T-P) concentrations in the influent were, respectively, 260-290 mg/L, 24-28 mg/L, and 1.4-1.8 mg/L. The COD, T-N, T-P removals in the pond with duckweed (74%, 84%, and 84%) were much higher than in the pond without duckweed (71%, 55%, and 58%). The duckweed greatly enhanced the first-order removal rates by 1.4, 2.0, and 3.2 times, respectively, for COD, T-N, and T-P in the ponds. Although the primary purification mechanisms in the ponds were sedimentation and adsorption, the duckweed grown with the relative growth rate of 0.07-0.16 d-1 showed nutrient uptake activity from the wastewater. Biofilms formed on the duckweed roots apparently promoted COD removal and degradation of organic nitrogen into ammonia. Stabilization ponds planted with duckweed are anticipated for use as co-beneficial systems for wastewater treatment and biomass production.


Assuntos
Araceae , Purificação da Água , Animais , Nitrogênio , Nutrientes , Tanques , Suínos , Vietnã , Eliminação de Resíduos Líquidos , Águas Residuárias
18.
Sci Total Environ ; 722: 137607, 2020 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-32213435

RESUMO

Nanoparticle capping agents are critical for controlling the growth, oxidation state, and final particle size during aqueous synthesis. However, despite the known phytotoxicity of cetyltrimethylammonium bromide (CTAB) to plants, it is used to synthesize metal oxide nanoparticles of uniform size and with mesoporous structure. Among the few studies that have investigated how CTAB influences nanoparticle toxicity, CTAB has never been identified as the primary cause of nanoparticle toxicity in environmental systems; rather nanoparticle surface charge or morphology was identified as the driver of toxicity in environmentally relevant systems. In the current study, CTAB release from CTAB surface modified Cu2O nanoparticles (SM-Cu2O NPs) inhibited duckweed (Landoltia punctata) growth, even when administered at subtoxic Cu concentrations. Organic ligands, such as humic acid (HA) and ethylenediaminetetraacetic acid (EDTA), lessened growth inhibition associated with exposure to SM-Cu2O NPs, likely through electrostatic and hydrophobic interactions with CTAB. Such results highlight the need for a more holistic approach to nanoparticle surface modification and improved communication between toxicologists and synthetic chemists to develop green alternatives for nanoparticle synthesis.


Assuntos
Araceae , Cobre , Nanopartículas Metálicas , Tamanho da Partícula
19.
Int J Phytoremediation ; 22(11): 1097-1109, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32102549

RESUMO

The objective of this study was to investigate the reduction of phosphorus from rice mill wastewater by using free floating aquatic plants. Four free floating aquatic plants were used for this study, namely water hyacinth, water lettuce, salvinia, and duckweed. The aquatic plants reduced the total phosphorus (TP) content up to 80% and chemical oxygen demand (COD) up to 75% within 15 days. The maximum efficiency of TP and COD reduction was observed with water lettuce followed by water hyacinth, duckweed, and salvinia. The study also aims to predict phosphorus removal by three modeling techniques, for example, linear regression (LR), artificial neural network (ANN), and M5P. Prediction has been done considering hydraulic retention time (HRT), hydraulic loading rate (HLR), and initial concentration of phosphorus (Cin) as input variables whereas the reduction rate of TP (R) has been considered as a predicted variable. ANN shows promising results as compared to M5P tree and LR modeling. The model accuracy is analyzed using three statistical evaluation parameters which are coefficient of determination (R2), root mean square error (RMSE), and means absolute error (MAE).


Assuntos
Araceae , Eichhornia , Oryza , Poluentes Químicos da Água/análise , Biodegradação Ambiental , Alface , Fósforo , Eliminação de Resíduos Líquidos , Águas Residuárias
20.
Int J Phytoremediation ; 22(10): 1019-1027, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32064901

RESUMO

Two greenhouse experiments were carried out to evaluate the phytoremediation potential, physiological responses and zinc (Zn) uptake kinetics of water lettuce (Pistia stratiotes L.). The phytoextraction experiment evaluated four doses of Zn (0.7 mg L-1 - represented the Zn in the nutrient solution, 1.8, 18 and 180 mg L-1 - corresponded to ten, hundred and a thousand times, respectively, the maximum permitted content for fresh water) at four different culture times (24, 48, 72 and 168 h). The Zn uptake kinetics of water lettuce were evaluated at two concentrations of Zn (1.8 and 18 mg L-1). The water lettuce attained the highest percentage removal at the lowest evaluated doses (0.7 and 1.8 mg L-1), reaching a maximum value of approximately 72% removal (when cultivated in 1.8 mg L-1 of Zn after 168 h of culture). The Zn uptake increased with culture time, increasing the synthesis of carotenoids at all doses evaluated. The highest doses of Zn resulted in a reduction in photosynthetic efficiency. The results showed a high potential of water lettuce to absorb and tolerate Zn, accumulating preferably in the roots, demonstrating that these plants are able to absorb large quantities of Zn in contaminated solution.


Assuntos
Araceae , Poluentes Químicos da Água/análise , Biodegradação Ambiental , Cinética , Zinco
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