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1.
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
2.
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
3.
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
4.
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
5.
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
6.
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
7.
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
8.
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
9.
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
10.
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
11.
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
12.
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
13.
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
14.
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
15.
Environ Sci Pollut Res Int ; 27(13): 15806-15814, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32088823

RESUMO

Phytoremediation potential of duckweeds (Lemna minuta, Lemna minor) to remove nutrients from simulated wastewater was analyzed. In two separate experiments, the two species were grown for 28 days in waters enriched with nitrate and phosphate to simulate nutrient concentrations of domestic wastewater. Water physical and chemical measurements (temperature, pH, conductivity, oxygen) and plant physiological and biochemical analysis (biomass, relative growth rate-RGR, nutrient and chlorophyll contents, peroxidative damage, bioconcentration factor-BCF) were made to test and compare the phytoremediation capacity of the two Lemna species. L. minuta biomass increased almost tenfold during the time-course of the treatment resulting in a doubling of the mat thickness and a RGR of 0.083 ± 0.001 g/g day. Maximum frond content of phosphate was reached by day 21 (increase over 165%) and nitrate by day 7 (10%). According to the BCF results (BCF > 1000), L. minuta was a hyperaccumulator for both nutrients. On the other hand, L. minor biomass and mat thickness decreased continuously during incubation (RGR = - 0.039 ± 0.004 g/g day). In L. minor fronds, phosphate content increased until day 14, after which there was a decrease until the end of the incubation. Frond nitrate content significantly decreased by day 7, but then remained relatively constant until the end of the experiment. L. minor proved to be hyperaccumulator for phosphates, but not for nitrates. Results indicated L. minuta has a greater potential than L. minor to remove both nutrients by bioaccumulation, especially phosphates, demonstrated also by better physiological and biochemical responses. However, during the incubation, the chlorophyll content of L. minuta mat did continuously decrease and peroxidative damage had increased until day 14, indicating that the system was under some kind of stress. Strategies to avoid this stress were discussed.


Assuntos
Araceae , Poluentes Químicos da Água/análise , Biodegradação Ambiental , Biomassa , Nutrientes , Águas Residuárias
16.
Bull Environ Contam Toxicol ; 104(5): 627-633, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32060589

RESUMO

Phytoremediation of industrial sewage sludge with Eichhornia crassipes, Salvinia molesta and Pistia stratiotes in pilot scale batch fed free water flow constructed wetlands was done in order to assess the suitability of remediated sludge as fertilizer. S. molesta showed the greatest decreases of Zn (36.0%), Fe (26.6%), Cu (32.6%), Cr (58.6%) and Ni, (26.9%) while P. startiotes and E. crassipes, respectively, showed the greatest Cd (27.1%) and Pb (42.4%) decreases. Metals, nutrients (total N and P) and fecal coliform in remediated sludge complied with regulatory standards and P. startiotes showed the greatest electrical conductivity (EC) (65.6%) decrease. The phytotoxicity assay on Lactuca sativa and Brassica oleraceae exhibited more than 50% of germination index from the sludge remediated with S. molesta. The results demonstrate that phytoremediation with hyper accumulators followed by phytotoxicity assay could be used to support decisions for the appropriate use of land disposed industrial sewage sludge.


Assuntos
Metais Pesados/análise , Esgotos/química , Traqueófitas/crescimento & desenvolvimento , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Áreas Alagadas , Araceae/crescimento & desenvolvimento , Biodegradação Ambiental , Eichhornia/crescimento & desenvolvimento , Resíduos Industriais/análise
17.
Sci Total Environ ; 710: 136318, 2020 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-32050368

RESUMO

Silver nanoparticles (AgNPs) are widely applied in several types of products since they act as a biocide. However, their high level of release into the environment can bring risks to ecosystems. Thus, the toxicity of AgNPs toward duckweed (Landoltia punctata) was investigated by monitoring the growth rate inhibition and the effect on the photosynthetic metabolism through morphological and ultrastructural analysis. The AgNPs were characterized by transmission electron microscopy and the effective diameter (dynamic light scattering) and zeta potential were determined. Plants were grown according to the environmental conditions recommended in ISO/DIS 20079 and then exposed to different concentrations of AgNPs. Inhibition of the growth rate was measured based on the EC50 and changes in the morphology, cellular structures and photosynthetic pigments were evaluated along with the silver accumulation. Although the results showed low growth inhibition when compared to other studies, significant damage to the ultrastructure, decreases in the photosynthetic pigments and starch grains, an increase in the phenolic compounds and physiological changes, such as a loss of color, were observed. Moreover, the accumulation of silver ions was noted and this could lead to bioamplification in consumer organisms, since duckweed belongs to the first level of the food chain.


Assuntos
Araceae , Nanopartículas Metálicas/química , Ecossistema , Fotossíntese , Prata
18.
PLoS One ; 15(2): e0228595, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32027708

RESUMO

Acid orange 74 (AO74) is a chromium-complex monoazo acid dye widely used in the textile industry. Due to being highly toxic and non-biodegradable, it must be removed from polluted water to protect the health of people and the environment. The aim of this study was two-fold: to evaluate the biosorption of AO74 from an aqueous solution by utilizing HCl-pretreated Lemna sp. (HPL), and to examine dye desorption from the plant material. The maximum capacity of AO74 biosorption (64.24 mg g-1) was reached after 4 h at the most adequate pH, which was 2. The biosorption capacity decreased 25% (to 48.18 mg g-1) during the second biosorption/desorption cycle and remained essentially unchanged during the third cycle. The pseudo-second-order kinetics model concurred well with the experimental results of assays involving various levels of pH in the eluent solution and distinct initial concentrations of AO74. NaOH (0.01 M) was the best eluent solution. The Toth isotherm model best described AO74 biosorption equilibrium data. FTIR analysis confirmed the crucial role of HPL proteins in AO74 biosorption. SEM-EDX and CLSM techniques verified the effective biosorption/desorption of the dye during the three cycles. Therefore, HPL has potential for the removal of AO74 dye from wastewaters.


Assuntos
Araceae/metabolismo , Compostos Azo/isolamento & purificação , Biodegradação Ambiental , Corantes/isolamento & purificação , Adsorção , Compostos Azo/toxicidade , Corantes/toxicidade , Ácido Clorídrico , Concentração de Íons de Hidrogênio , Cinética , Indústria Têxtil , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Poluentes Químicos da Água/toxicidade
19.
PLoS One ; 15(2): e0228560, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32027711

RESUMO

Culture-independent characterization of microbial communities associated with popular plant model systems have increased our understanding of the plant microbiome. However, the integration of other model systems, such as duckweed, could facilitate our understanding of plant microbiota assembly and evolution. Duckweeds are floating aquatic plants with many characteristics, including small size and reduced plant architecture, that suggest their use as a facile model system for plant microbiome studies. Here, we investigated the structure and assembly of the duckweed bacterial microbiome. First, a culture-independent survey of the duckweed bacterial microbiome from different locations in New Jersey revealed similar phylogenetic profiles. These studies showed that Proteobacteria is a dominant phylum in the duckweed bacterial microbiome. To observe the assembly dynamics of the duckweed bacterial community, we inoculated quasi-gnotobiotic duckweed with wastewater effluent from a municipal wastewater treatment plant. Our results revealed that duckweed strongly shapes its bacterial microbiome and forms distinct associations with bacterial community members from the initial inoculum. Additionally, these inoculation studies showed the bacterial communities of different duckweed species were similar in taxa composition and abundance. Analysis across the different duckweed bacterial communities collected in this study identified a set of "core" bacterial taxa consistently present on duckweed irrespective of the locale and context. Furthermore, comparison of the duckweed bacterial community to that of rice and Arabidopsis revealed a conserved taxonomic structure between the duckweed microbiome and the terrestrial leaf microbiome. Our results suggest that duckweeds utilize similar bacterial community assembly principles as those found in terrestrial plants and indicate a highly conserved structuring effect of leaf tissue on the plant microbiome.


Assuntos
Araceae/microbiologia , Microbiota , Filogenia , Folhas de Planta/microbiologia , Arabidopsis/microbiologia , Bactérias/genética , New Jersey , Oryza/microbiologia , Proteobactérias , RNA Ribossômico 16S/análise , Águas Residuárias/microbiologia
20.
Water Res ; 172: 115522, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32006774

RESUMO

Selenium (Se) and zinc (Zn) are essential micronutrients that are often lacking in the diet of humans and animals, leading to deficiency diseases. Lemna and Azolla are two aquatic plants with a substantial protein content, which offer the possibility of utilizing them to remove Se and Zn from (waste)water while producing micronutrient-enriched dietary proteins and fertilizers. In this study, we explored interaction effects occurring between Se and Zn when these micronutrients are taken up by Azolla and Lemna. The two aquatic plants were grown on hydroponic cultures containing 0-5.0 mg/L of Se (Se(IV) or Se(VI)) and Zn. The Se and Zn content of the plants, growth indicators, bioconcentration factor (BCF) and Se/Zn removal efficiency from the water phase were evaluated. The results demonstrated that Se(IV) is more toxic than Se(VI) for both plant species, as evidenced by the remarkable decrease of biomass content and root length when exposed to Se(IV). Both aquatic plants took up around 10 times more Se(IV) than Se(VI) from the medium. Moreover, the Se accumulation and removal efficiency increased by 66-99% for Se(IV) and by 34-59% for Se(VI) in Lemna when increasing Zn dosage from 0 to 5.0 mg/L in the medium, whereas it declined by 13-26% for Se(IV) and 21-35% for Se(VI) in Azolla, suggesting a synergetic effect in Lemna, but an antagonistic effect in Azolla. The maximum BCF of Se in Lemna and Azolla were 507 and 667, respectively. The protein content in freeze-dried Lemna and Azolla was approximately 17%. The high tolerance and accumulation of Se and Zn in Lemna and Azolla, combined with their rapid growth, high protein content and transformation of inorganic to organic Se species upon Se(IV) exposure make Lemna and Azolla potential candidates for the production of Se(IV)- and Zn-enriched biomass that can be used as crop fertilizers or protein-rich food/feed supplements or ingredients. Accordingly, by growing the Azolla and Lemna on wastewater, a high-value product can be produced from wastewater while recovering resources.


Assuntos
Araceae , Selênio , Oligoelementos , Animais , Humanos , Micronutrientes , Zinco
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