Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 739
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Ecotoxicol Environ Saf ; 182: 109429, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31323522

RESUMO

Both water and non-water soluble ionic liquids (ILs) may be toxic where ILs soluble in water can be released into aquatic ecosystems. Toxicity of ILs can be determined as effective nominal concentration EC50 because it is important to assess the toxicity of ILs by an inhibition assay, which can evaluate the toxicological danger of ILs. A novel model is introduced for desk calculations of chemical toxicity of ILs based on Vibrio fischeri with more reliance on their answers as one could attach to the more complex outputs. It requires only specific elemental compositions of cations and anions as well as the presence of some molecular fragments in cations with particular anions. The measured values of logEC50(/µM) for 187 ILs corresponding to 250 experimental data were used to derive and test of the new model. For 153 ILs (203 datapoints), where the reported values of logEC50(/µM) as training and test sets by one of the best quantitative structure-activity relationship (QSAR) were available, the new method gives more reliable predictions. The present simple method is also tested with further 34 (47 datapoints), which confirm good forecasting reliability of the new model.


Assuntos
Líquidos Iônicos/toxicidade , Testes de Toxicidade/métodos , Aliivibrio fischeri/efeitos dos fármacos , Ânions , Cátions/química , Líquidos Iônicos/química , Relação Quantitativa Estrutura-Atividade , Reprodutibilidade dos Testes
2.
Chemosphere ; 233: 292-299, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31176130

RESUMO

The exposure reality of chemicals is usually in mixtures, the effects of which are usually extrapolated from individual results. Yet, such extrapolation is challenged by the alteration between monotonic concentration-response curves (CRCs) and non-monotonic hormetic CRCs in individual and mixture effects. In the present study, we aimed to investigate the occurrence of such alterations using 1-alkylimidazolium bromide ([amim]Br) and 1-alkylpyridinium bromide ([apyr]Br) ionic liquids (ILs) as model chemicals. Effects of four [amim]Br, four [apyr]Br, and their quaternary mixtures designed by uniform design were measured on Aliivibrio fischeri in a time-dependent fashion. Results showed that the individual [amim]Br showed monotonic CRCs. Their inhibition increased over the length of the side-chain and decreased over the exposure time. The [amim]Br mixtures showed non-monotonic hormetic CRCs, where the stimulations increased over exposure time. The individual [apyr]Br had non-monotonic hormetic CRCs, and their stimulation increased over the length of the side-chain. Meanwhile, the [apyr]Br mixtures had monotonic CRCs without any stimulation. Notably, the positive contributors to the mixture effects were [emim]Br or [epyr]Br which had the shortest side-chain among the components. The findings can facilitate accurate prediction on the environmental effects of ILs with specific considerations on hormetic and mixture effects.


Assuntos
Aliivibrio fischeri/efeitos dos fármacos , Líquidos Iônicos/toxicidade , Misturas Complexas/química , Misturas Complexas/toxicidade , Hormese/efeitos dos fármacos , Imidazóis/química , Imidazóis/toxicidade , Líquidos Iônicos/química , Testes de Toxicidade/métodos
3.
Ecotoxicol Environ Saf ; 181: 187-193, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31195227

RESUMO

Microbial polysaccharides, due to their unique physiochemical properties, have found application in the food industry, cosmetics, pharmacy and medicine. In the environment, microbes can use polysaccharides to alleviate the adverse effects of heavy metals in their close proximity. This adaptive property shows interesting potential for bioremediation. Herein, the effects of the exopolysaccharides (EPS) levan, produced by the bacterium Bacillus licheniformis NS032 and pullulan, produced by the fungus Aureobasidium pullulans CH-1 in the presence of copper (Cu2+) have been investigated for the first time on antioxidant enzyme activity, respiration and Cu2+ bioaccumulation of Daphnia magna as well as the bioluminescence of Vibrio fischeri. Both EPS decreased toxicity of Cu2+ in the acute test with D. magna. The activity of catalase (CAT) was significantly diminished after acute exposure to Cu2+ in comparison to treatments with Cu2+ and EPS, while in the prolonged acute exposure the CAT activity did not show statistically significant (P ≤ 0.05) differences between treatments with and without the EPS. According to ICP-MS results, during prolonged acute exposure of neonates, the bioaccumulation of Cu2+ in treatments without the EPS was 52.03 µg/g of biomass (wet), while in treatments with EPS, the bioaccumulation was lower by one order of magnitude. The respiration of neonates during acute exposure to Cu2+ with or without the EPS was monitored using the MicroOxymax respirometer, and the results show the EPS can positively effect the respiration. In the case of bacterial bioluminescence, the toxicity of Cu2+ decreased in treatments with EPS (30 min EC10) from 3.54 mg/L to 140.61 mg/L (levan) and 45.00 mg/L (pullulan). This study demonstrates protective effect of EPS against Cu2+ toxicity on D. magna and V. fischeri, and opens the door for further investigation of potential application of levan and pullulan in bioremediation of heavy metals and mitigation of their adverse effects in the aquatic environment.


Assuntos
Cobre/toxicidade , Frutanos/farmacologia , Glucanos/farmacologia , Poluentes Químicos da Água/toxicidade , Aliivibrio fischeri/química , Aliivibrio fischeri/efeitos dos fármacos , Animais , Ascomicetos/metabolismo , Bacillus licheniformis/metabolismo , Catalase/metabolismo , Cobre/farmacocinética , Daphnia/efeitos dos fármacos , Daphnia/enzimologia , Daphnia/crescimento & desenvolvimento , Daphnia/metabolismo , Luminescência , Substâncias Protetoras/farmacologia , Poluentes Químicos da Água/farmacocinética
4.
Environ Int ; 129: 185-193, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31128438

RESUMO

Sulfonamides (SAs), a kind of commonly used antibiotics, have been frequently detected in the environment. Due to their potential threat to the ecological environment, the toxicity of SAs to bacteria have been determined in depth, and the toxic mechanism is found to target dihydropteroate synthase (DHPS). However, other toxic mechanism may also exist for SAs, which is still unclear to us. In this paper, the toxic mechanism of sulfachloropyridazine (SCP, as a representative of SAs) was investigated thoroughly on Aliivibrio fischeri (A. fischeri) from the perspective of quorum sensing (QS). The results reveal that SCP may act on three signaling pathways, i.e., Pathway I, II and III, which triggers, maintains and destroys the homeostasis of A. fischeri respectively. In Pathway I, SCP changes the active form of LitR that regulates the expression of lux-related genes, inducing inhibition on bacterial growth while stimulation on luminescence; in Pathway II, SCP facilitates the production of C6HSL signaling molecules, maintaining the homeostasis in LitR and DHPS proteins; whereas in Pathway III, SCP typically combines with DHPS to inhibit the folate metabolism. This study can provide a deeper and more comprehensive understanding on the toxicity of SAs and help the environmental risk assessment of SAs.


Assuntos
Comunicação Celular/efeitos dos fármacos , Sulfonamidas/farmacologia , Aliivibrio fischeri/efeitos dos fármacos , Percepção de Quorum , Sulfanilamida
5.
Chemosphere ; 230: 258-267, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31108436

RESUMO

The elimination of 2,3,6-trichloroanisole (2,3,6-TCA), which produces a musty-earthy off-odor in water, by an ultraviolet (UV)/H2O2 process was assessed. The removal of 88.1% of 2,3,6-TCA in ultrapure water (UPW) was achieved using an initial 2,3,6-TCA concentration of 1 µg L-1 (4.73 nM), a H2O2 concentration of 20 mg L-1 (0.588 mM), a UV intensity of 1.44 mW cm-2 and a pH of 8.2. The reaction was found to be pseudo first order with a rate constant (kobs) of 0.0340 min-1. Both the removal efficiency and kobs increased significantly upon increasing the H2O2 concentration from 10 to 50 mg L-1. The second order rate constant (kHO·,2,3,6-TCA) in competition kinetic trials was determined to be 8.17 × 107 M-1s-1. Degradation products generated during both the UV photolysis and UV/H2O2 treatment of 2,3,6-TCA solutions were analyzed using ultrahigh resolution gas chromatography/mass spectrometry, and the degradation mechanism was proposed. The toxicities of water solutions during both processes were assessed via a luminescence method in conjunction with Vibrio fischeri. The pH and Cl-, HCO3- and natural organic matter concentrations of the aqueous medium were all found to significantly affect the removal of 2,3,6-TCA. The degradation rates of trichloroanisoles (TCAs) in real-world water samples demonstrated that UV/H2O2 has significant potential with regard to controlling TCAs as pollutants in water.


Assuntos
Anisóis/análise , Peróxido de Hidrogênio/química , Fotólise , Raios Ultravioleta , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Aliivibrio fischeri/efeitos dos fármacos , Anisóis/efeitos da radiação , Anisóis/toxicidade , Cinética , Oxirredução , Testes de Toxicidade Aguda , Poluentes Químicos da Água/efeitos da radiação , Poluentes Químicos da Água/toxicidade
6.
Sci Total Environ ; 677: 1-8, 2019 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-31051379

RESUMO

The ecotoxicological evaluation of combined sewer overflow (CSO) disinfectants, with their degradation products, is important for ensuring safe use. For this form of toxicity, data for organisms representing different trophic levels are needed. We studied the toxicity of the alternative disinfectants peracetic acid (PAA), performic acid (PFA) and chlorine dioxide (ClO2) and their degradation products hydrogen peroxide (H2O2) and chlorite (ClO2-) on Vibrio fischeri and Daphnia magna. ClO2 was more toxic to D. magna (EC50 < 0.09 mg/L) and PFA was most toxic to V. fischeri (EC50 0.24 mg/L). EC50 of PFA, PAA, ClO2, H2O2 and ClO2- on D. magna were 0.85, 0.78, <0.09, 3.46 and 0.36 mg/L, respectively. Similarly, EC50 of PFA, PAA, ClO2, H2O2 and ClO2- on V. fischeri were 0.24, 0.42, 1.10, 5.67 and 30.93 mg/L, respectively. For both PFA and ClO2, the degradation in water was faster than for PAA, H2O2 and chlorite. Using these data together with literature values, we derived environmental quality standards. By combining these with typical concentrations of disinfectants used for CSOs, we estimated the dilution required for discharging CSOs after disinfection, which can be used for quick assessment of the environmental feasibility of disinfection systems at specific CSO sites. Minimal dilutions in the receiving water, in the orders of 44, 70 or 138-fold, are needed for ClO2, PFA and PAA, respectively. This highlights PFA as the most widely applicable disinfectant, taking into account both its efficiency and the lower risk of unwanted environmental effects.


Assuntos
Aliivibrio fischeri/efeitos dos fármacos , Daphnia/efeitos dos fármacos , Desinfetantes/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Cloretos/toxicidade , Compostos Clorados/toxicidade , Desinfecção , Formiatos/toxicidade , Peróxido de Hidrogênio/toxicidade , Óxidos/toxicidade , Ácido Peracético/toxicidade , Esgotos
7.
Ecotoxicol Environ Saf ; 180: 457-465, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31121552

RESUMO

Sludge-based biochars (SBB) were prepared to evaluate their physiochemical properties and safety performance for the possible application in soil amendments in this study. SBB were produced at the temperatures ranging from 300 to 900 °C at 200 °C intervals. Both the solid fraction and the soluble organic fraction of SBB were analyzed. The pyrolysis temperature was found to affect the characteristics of solid fraction of the SBB greatly, in terms of the pH, surface area and functional groups. The content and composition of dissolved organic matter in SBB were influenced evidently by pyrolysis temperatures, which was mainly comprised of humic-like compounds with the molecular weight in a range of 0.13-2.4 × 105 kDa. The safety performance of heavy metals in SBB at different temperatures were analyzed: (i) The bioavailable fractions (F1+F2+F3) of heavy metals significantly decreased from 91.65% to 9.44% for Cu, from 98.82% to 63.34% for Zn, from 97.91% to 52.11% for As, from 55.91% to 4.87% for Pb, from 78.20% to 12.50% for Cd, and from 73.51% to 9.57% for Cr when sludge was pyrolyzed to biochars at 900 °C.; (ii) Acid and alkaline conditions promoted the leaching of heavy metals from SBB. The luminescence inhibition of Vibrio fischeri was significantly decreased from 81.41% to 6.01% with the increasing pyrolysis temperatures. Compared with the raw sludge addition, the shoot length, root length and activities of soil microbes in sandy soil and loamy soil with pyrolyzed sludge under different pyrolysis temperatures were increased by 37.5-53.32%, 66.81-96.45%, 92.31-157.69% and 154.74-195.76%, respectively. The biotoxicity tests indicated the relatively safe and reliable performance of SBB. The study provided significant perspectives on the application of SBB as the potential soil amendments.


Assuntos
Carvão Vegetal/química , Fertilizantes , Metais Pesados/análise , Esgotos/química , Poluentes do Solo/análise , Solo/química , Aliivibrio fischeri/efeitos dos fármacos , Estudos de Viabilidade , Temperatura Alta , Metais Pesados/toxicidade , Pirólise , Poluentes do Solo/toxicidade
8.
Environ Pollut ; 251: 811-820, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31125811

RESUMO

The humic-like substances were the main organic components in most wastewater (e.g. domestic sewage, toilet wastewater and landfill leachate). Two types of actual humic-like substances (fulvic acid (FA) and biologically treated landfill leachate (BTLL)) were selected to describe the changes in the properties of humic-like substances (complexation ability, aromaticity and mobility) during electrochemical oxidation. Meanwhile, the acute cytotoxicity of FA and BTLL was also tested by acute toxicological test of luminescent bacteria. The results showed that the consumption of coordinating groups such as phenolic groups and hydrogen bonds reduced the complexation ability of FA and BTLL. The functional groups were degraded with the removal order of quinone group, phenolic group and aromatic group, and finally realized the molecular saturation and aromaticity decrease for humic-like substances. The mobility of FA and BTLL was decreased because of the enhancement of hydrophobicity during electrolysis process. Furthermore, the available chlorine produced during electrochemical oxidation was the main acute cytotoxicity substance, therefore, it is necessary to remove it before discharge in order to reduce ecological risks. This study provides a basis for understanding and evaluating the electrochemical degradation process of humic-like substances in detail.


Assuntos
Benzopiranos/análise , Recuperação e Remediação Ambiental/métodos , Substâncias Húmicas/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Aliivibrio fischeri/efeitos dos fármacos , Técnicas Eletroquímicas , Substâncias Húmicas/toxicidade , Oxirredução , Poluentes Químicos da Água/toxicidade
9.
Environ Sci Pollut Res Int ; 26(16): 16366-16377, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30980375

RESUMO

The creation of pit lakes is usually an acceptable solution from the landscaping point of view for voids left by discontinued open-pit mines. However, without rehabilitation, these voids represent a potential environmental risk. The aim of the present work was to assess, for the first time, the water quality, i.e., physicochemical characteristics, metal and metalloid (MM) content, and ecotoxicity of the waters of the El Cobre Blue Lagoon, a pit lake formed in an open-pit copper mine in Cuba. Potential effects of rainy season vs. dry season and spatial location (different depths) on water characteristics were considered. Results revealed that water contained was moderately acidic (pH = 4.6 ± 0.2), with high electrical conductivity (EC = 3.02 ± 0.03 mS cm-1), whatever the season. Dissolved oxygen (DO = 9.9 ± 2.0 mg L-1), total dissolved solid (TDS = 7003 ± 245 mg L-1), and sulfate concentration (6556 ± 1410 mg L-1) in the El Cobre Blue Lagoon water were above acceptable limits for sources of surface water as recommended by Cuban standard (NC 1021:2014). High copper (43.6 ± 1.7 mg L-1) and manganese (24.1 ± 1.1 mg L-1) contents were detected. Except for EC, sulfates, chlorides, TDS, nitrates, and phosphates, other physicochemical parameters were stable between dry and rainy seasons (p < 0.05). El Cobre Blue Lagoon waters showed an ecotoxicological impact on Vibrio fischeri. No significant differences were detected between all sampling points in the lake for each parameter monitored for a given time. These first results show the spatial homogeneity but poor quality of waters from El Cobre Blue Lagoon. Remediation processes need to be implemented in order to lessen the human and environmental health risk and favor potential water reuse. We suggest the use of constructed wetlands for water treatment. This preliminary research work can serve to alert Cuban local public authorities to the need to rehabilitate such sites.


Assuntos
Lagos/análise , Mineração , Qualidade da Água , Aliivibrio fischeri/efeitos dos fármacos , Cobre , Cuba , Ecotoxicologia/métodos , Monitoramento Ambiental/métodos , Humanos , Lagos/química , Metais/análise , Nitratos/análise , Estações do Ano , Sulfatos/análise , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
10.
Ecotoxicol Environ Saf ; 177: 25-31, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30954009

RESUMO

Pesticides and medications have adverse effects in non-target organisms that can lead to different modes of action (MOAs). However, no study has been performed to compare the MOAs between different levels of aquatic species. In this study, theoretical equations of interspecies relationship and excess toxicity have been developed and used to investigate the MOAs among fish, Daphnia magna, Tetrahymena pyriformis and Vibrio fischeri for pesticides and medications. The analysis on the interspecies correlation and excess toxicity suggested that fungicides, herbicides and medications share the similar MOAs among the four species. On the other hand, insecticides share different MOAs among the four species. Exclusion of insecticides from the interspecies correlation can significantly improve regression coefficient. Interspecies relationship is dependent not only on the difference in interaction of chemicals with the target receptor(s), but also on the difference in bio-uptake between two species. The difference in physiological structures will result in the difference in bioconcentration potential between two different trophic levels of organisms. Increasing of molecular size or hydrophobicity will increase the toxicity to higher level of aquatic organisms; on the other hand, chemical ionization will decrease the toxicity to higher level organisms. Hydrophilic compounds can more easily pass through cell membrane than skin or gill, leading to greater excess toxicity to Vibrio fischeri, but not to fish and Daphnia magna.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Praguicidas/toxicidade , Poluentes Químicos da Água/toxicidade , Aliivibrio fischeri/efeitos dos fármacos , Animais , Daphnia/efeitos dos fármacos , Peixes/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Praguicidas/metabolismo , Praguicidas/farmacologia , Tetrahymena pyriformis/efeitos dos fármacos , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/farmacologia
11.
Ecotoxicol Environ Saf ; 176: 309-320, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-30951978

RESUMO

The pollution by industrial and municipal effluents are major sources of concerns. Fish cell cultures were applied in different strategies of the evaluation of effluents, particularly whole toxicity, toxicity identification evaluation and mode of action studies based in adverse outcome pathways. Whole effluent toxicity was evaluated using a battery of five model systems from four trophic levels: Daphnia magna was the most sensitive system, followed by the hepatoma fish cell line PLHC-1, the bacterium Allivibrio fischeri, the fibroblastic fish cell line RTG-2 and the algae Chlorella vulgaris, detecting a risk of eutrofization. The uptake of neutral red was more sensitive than the content of protein assay. The main morphological alterations observed were cell loss, hydropic degeneration, and a general loss of lysosomes and of their perinuclear distribution. The toxicity was characterized in PLHC-1 cells through toxicity identification evaluation, in which a partial reduction with graduation at pH 11, filtration, aeration and addition of thiosulfate or EDTA was shown; on the other hand, a low sorption in solid phase extraction suggested that the main responsible were not organic compounds. Consequently, it was not necessary to apply an effect directed analysis HPLC fractionation. In the chemical identification phase, Zn, Cd, As, Cu and Pb were quantified in decreasing concentrations. In the toxicity confirmation phase, a reconstituted sample and individual solutions, presented decreasing toxicity: Zn > Pb > As+5 > Cd > Cu > As+3, the global toxicity being explained by response addition. In the last step, the mode of action was investigated using five specific biomarkers. While metallothionein and succinate dehydrogenase activity were increased, no changes occurred for lysosomal function, acetylcholinesterase and EROD activities, the responsibility of the toxicity for the elements found being confirmed.


Assuntos
Monitoramento Ambiental/métodos , Fibroblastos/efeitos dos fármacos , Peixes , Poluentes Químicos da Água/toxicidade , Acetilcolinesterase/metabolismo , Aliivibrio fischeri/efeitos dos fármacos , Animais , Biomarcadores/metabolismo , Técnicas de Cultura de Células , Linhagem Celular , Chlorella vulgaris/efeitos dos fármacos , Daphnia/efeitos dos fármacos , Fibroblastos/metabolismo , Peixes/metabolismo , Metalotioneína/metabolismo , Vermelho Neutro/metabolismo , Testes de Toxicidade
12.
Sci Total Environ ; 671: 270-279, 2019 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-30928756

RESUMO

Electro-oxidation (EO) by using graphite anode and at relatively low current densities was successfully applied for the degradation of commercial naphthenic acids (NAs) mixture in water samples. At current densities of 0.5, 2.5, and 5 mA/cm2, acid extractable fraction (AEF) was removed by 42.2%, 57.0% and 67.9%, respectively, while classical NAs were degraded by 76.9%, 77.6% and 82.4%, respectively. EO reactivity towards NAs increased with increasing the carbon number (n) and was higher for cyclic NAs compared to the acyclic component. Oxidized NAs containing O3 and O4 were also degraded effectively during EO. The biodegradability of organics in the NA mixture was clearly improved by 1.7, 2.5 and 2.7 folds when the samples were pre-treated with EO at current densities of 0.5, 2.5, and 5 mA/cm2, respectively. The aromatic fraction in the commercial NA mixture consisted mainly of single-ring aromatics and was degraded effectively by EO. Biodegradation alone was able to reduce the toxicity of the commercial NA mixture towards Vibrio fischeri; however, the combination of EO with biodegradation resulted in a complete removal of the toxicity, showing a synergistic effect of combining these two processes. Coupling EO with aerobic biodegradation can result in an effective and energy-efficient treatment option for NA-bearing waters such as oil sands process water (OSPW) and refinery effluents.


Assuntos
Aliivibrio fischeri/efeitos dos fármacos , Ácidos Carboxílicos/análise , Grafite/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Biodegradação Ambiental , Técnicas Eletroquímicas , Eletrodos , Oxirredução
13.
J Environ Sci Health B ; 54(5): 432-440, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30821587

RESUMO

Degradation of atrazine by catalytic ozonation in the presence of iron scraps (ZVI/O3) was carried out. The key operational parameters (i.e., initial pH, ZVI dosage, and ozone dosage) were optimized by the batch experiments, respectively. This ZVI/O3 system exhibited much higher degradation efficiency of atrazine than the single ozonation, ZVI, and traditional ZVI/O2 systems. The result shows that the pseudo-first-order constant (0.0927 min-1) and TOC removal rate (86.6%) obtained by the ZVI/O3 process were much higher than those of the three control experiments. In addition, X-ray diffraction (XRD) analysis indicates that slight of γ-FeOOH and Fe2O3 were formed on the surface of iron scrap after ZVI/O3 treatment. These corrosion products exhibit high catalytic ability for ozone decomposition, which could generate more hydroxyl radical (HO•) to degrade atrazine. Six transformation intermediates were identified by liquid chromatography-mass spectrometry (LC-MS) analysis in ZVI/O3 system, and the degradation pathway of atrazine was proposed. Toxicity tests based on the inhibition of the luminescence emitted by Photobacterium phosphoreum and Vibrio fischeri indicate the detoxification of atrazine by ZVI/O3 system. Finally, reused experiments indicate the approving recyclability of iron scraps. Consequently, the ZVI/O3 system could be as an effective and promising technology for pesticide wastewater treatment.


Assuntos
Atrazina/química , Atrazina/toxicidade , Ferro/química , Ozônio/química , Testes de Toxicidade Aguda/métodos , Aliivibrio fischeri/efeitos dos fármacos , Catálise , Cromatografia Líquida , Corrosão , Radical Hidroxila/química , Espectrometria de Massas , Oxirredução , Photobacterium/efeitos dos fármacos , Águas Residuárias/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/toxicidade , Purificação da Água/métodos , Difração de Raios X
14.
Chemosphere ; 222: 789-796, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30739063

RESUMO

Explosives, pesticides, and pharmaceuticals contain toxic nitroaromatic compounds that may form even more toxic azo compounds if they encounter reducing conditions in the environment. We investigated the mechanism by which 4,4'-dimethoxyazobenzene forms in anaerobic sludge incubations of 4-nitroanisole, an analog for the insensitive munitions compound 2,4-dinitroanisole (DNAN). Because studies have reported the mechanism to involve the coupling of reduced nitroaromatic intermediates, specifically aromatic amines and nitrosoaromatics, by nucleophilic processes, we abiotically paired 10 mM 4-aminoanisole with 2 mM 4-nitrosoanisole in nitrogen-flushed microcosms. However, only 7 µM of 4,4'-dimethoxyazobenzene had formed after 24 h. We identified the major product to be 4-methoxy-4'-nitrosodiphenylamine. Repeating this experiment in phosphate buffer at pH 5.1, 7.1, and 8.6 demonstrated that the formation of this unexpected product is acid catalyzed. We found that 4-methoxy-4'-nitrosodiphenylamine is more toxic than 4,4'-dimethoxyazobenzene to the bioluminescent bacterium Aliivibrio fischeri, with IC50 values of 0.1 µM and 0.5 µM, respectively. Both products are several orders of magnitude more toxic than reduced 4-nitroanisole intermediates 4-aminoanisole and 4-nitrosoanisole, as well as DNAN and its aromatic amine metabolites. Six-fold more 4,4'-dimethoxyazobenzene formed when we incubated 4-nitrosoanisole with ascorbic acid, a reducing agent, than when we incubated 4-nitrosoanisole with 4-aminoanisole in the absence of ascorbic acid. We therefore suspect that 4-hydroxylaminoanisole, the first reduction product of 4-nitrosoanisole, is a better nucleophile than 4-aminoanisole and couples more readily with 4-nitrosoanisole. Slightly basic and reducing conditions can prevent the formation and persistence of toxic coupling products on sites contaminated with nitroaromatics, i.e. DNAN-contaminated firing ranges.


Assuntos
Anisóis/química , Aliivibrio fischeri/efeitos dos fármacos , Aminas/química , Anisóis/toxicidade , Compostos Azo/química , Substâncias Explosivas/química , Substâncias Explosivas/toxicidade , Oxirredução , Esgotos/química
15.
Ecotoxicol Environ Saf ; 172: 556-565, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30776578

RESUMO

A library of 24 pyridinium-, imidazolium-, and cholinium-based ionic liquids (ILs) with varying alkyl chain from C2 to C16 was toxicologically profiled using naturally luminescent marine bacteria Vibrio fischeri. The toxicity (30-min EC50) of studied ILs to Vibrio fischeri ranged from 7.82 µM (4.2 mg/L) (PyC12Phe) to 3096 µM (1227 mg/L) (ImidC2Phe), i.e. from "toxic" (EC50 1-10 mg/L) to "not harmful" (EC50 > 100 mg/L). Inhibition of the bacterial luminescence upon 30-min exposure to ILs correlated well with bacterial viability (exposure for 4 h). The toxicity of studied ILs was largely driven by the length of the alkyl chain (hydrophobicity) and not the type of cationic part of the IL: starting from C10 all the ILs irrespective of the cationic part proved "toxic". The toxicity of the studied ILs was increasing in parallel to their hydrophobicity up to log Kow = 1 (C8-C10) and then levelling up, being consistent with the previously obtained analogous data sets. The "cut-off" effect reported in this study for longer chain length members of the ILs series leads to the "limit" toxicity level for this type of ILs to be ca. 8 mM. Two open-access online tools (www.molinspiration.com and www.vcclab.org) have been applied for the calculation of the Kow values for the 24 ILs reported in this study and 21 ILs reported in the literature. This lead to plotting two nonlinear monotonic correlations between the values of experimental log (1/EC50) and calculated log Kow. The limitation of the online tools and an effect of the ILs structure on the "cut-off" effect have been discussed. The challenge of developing low microbial toxicity surface active ILs remains a significant task to overcome. Our results shed light on the new approaches for designing environmentally benign ILs and functional surfactants. As the hydrophobicity of the ILs significantly correlated with the toxicity, the Vibrio fischeri assay could be considered a powerful tool in providing toxicity data for building and evaluating the QSAR toxicity models for ILs.


Assuntos
Aliivibrio fischeri/efeitos dos fármacos , Imidazóis/toxicidade , Líquidos Iônicos/toxicidade , Fenilalanina/toxicidade , Compostos de Piridínio/toxicidade , Cátions , Determinação de Ponto Final , Interações Hidrofóbicas e Hidrofílicas , Medições Luminescentes , Viabilidade Microbiana/efeitos dos fármacos , Testes de Toxicidade
16.
Chemosphere ; 222: 381-390, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30711727

RESUMO

This paper discusses the impact of two nitrofuran-derived drugs, namely furazolidone and nitrofurantoin on growth of oat and common radish as well as their impact on bacteria Allivibrio fischeri and crustaceans Heterocypris incongruens. Results indicated that both compounds were highly phytotoxic for radish (R. sativus) being simultaneously nearly not harmful for oat (A. sativa). Growing inhibition of shoots, roots, fresh matter and photosynthetic pigments is correlated with growing concentration of drugs in soil. Ecotoxicological impact of both compounds on model luminescence bacteria Aliivibrio fischeri and freshwater crustaceans Heterocypris incongruens as a representative organisms of two different level of food chain, is also reported herein, and the obtained data show significant toxicity against these two organisms. Basing on obtained results, it was concluded that both nitrofuran drugs in case of distribution through environment, by improper utilisation after use or unplanned environmental intoxication with unused drugs may cause serious environmental problems and therefore both should be handled with a reasonable care at any step of their production or utilisation.


Assuntos
Ecotoxicologia , Furazolidona/toxicidade , Nitrofuranos/toxicidade , Nitrofurantoína/toxicidade , Aliivibrio fischeri/efeitos dos fármacos , Animais , Antibacterianos/toxicidade , Avena/efeitos dos fármacos , Avena/crescimento & desenvolvimento , Crustáceos/efeitos dos fármacos , Nitrofuranos/química , Raphanus/efeitos dos fármacos , Raphanus/crescimento & desenvolvimento , Poluentes do Solo/toxicidade
17.
Artigo em Inglês | MEDLINE | ID: mdl-30642109

RESUMO

This work introduces the potential synergistic toxicity of binary mixtures of pesticides and pharmaceuticals, which have been detected in substantial amounts in major river basins in South Korea. Different dose-response curve functions were employed in each experimental toxicity dataset for Aliivibrio fischeri. We tested the toxicity of 30 binary mixtures at two effect concentrations: high effect concentration [EC50] and low effect concentration (EC10) ranges. Thus, the toxicological interactions were evaluated at 60 effected concentration data points in total and based on model deviation ratios (MDRs) between predicted and observed toxicity values (e.g., three types of combined effects: synergistic (MDR > 2), additive (0.5 ≤ MDR ≤ 2), and antagonistic (MDR < 0.5)). From the 60 data points, MDRs could not be applied to 17 points, since their toxicities could not be measured. The result showed 48%-additive (n = 20), 40%-antagonistic (n = 17), and 12%-synergistic (n = 6) toxicity effects from 43 binaries (excluding the 17 combinations without MDRs). In this study, EC10 ratio mixtures at a low overall effect range showed a general tendency to have more synergistic effects than the EC50 ratio mixtures at a high effect range. We also found an inversion phenomenon, which detected three binaries of the combination of synergism at low concentrations and additive antagonism at high concentrations.


Assuntos
Aliivibrio fischeri/efeitos dos fármacos , Praguicidas/toxicidade , Medicamentos sob Prescrição/toxicidade , Rios/microbiologia , Poluentes Químicos da Água/toxicidade , Relação Dose-Resposta a Droga , Interações de Medicamentos , Praguicidas/farmacologia , República da Coreia , Poluentes Químicos da Água/farmacologia
18.
Chemosphere ; 221: 640-646, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30669109

RESUMO

The widespread use of diesel as a transportation fuel and the introduction of biodiesel into the world energy matrix increase the likelihood of aquatic contamination with these fuels. In this case, it is important to know the environmental impacts caused by water-soluble fraction (WSF) of these fuels, since it is the portion that can result in long-term impacts and affect regions far away from the location of a spill. Therefore, we evaluated and compared the aquatic ecotoxicity of the WSF of biodiesel and diesel through acute ecotoxicity tests with the aquatic microcrustacean Daphnia magna and the marine bacteria Aliivibrio fischeri, as well as chronic ecotoxicity tests with D. magna. The WSF of diesel was 2.5-4 folds more toxic than the WSF of biodiesel in acute ecotoxicity tests. Similarly, a comparison of the chronic ecotoxicity demonstrated that the WSF of diesel was more toxic than the WSF of biodiesel. WSF of diesel causes chronic effects on reproduction, longevity and growth of D. magna (NOEC was 12.5, 12.5, 6.25%, respectively), while WSF of biodiesel did not present significantly different results compared to the control for any of the parameters evaluated in any of the dilutions tested (NOEC> 25%). To the best of our knowledge, this is the first study that compares the chronic ecotoxicity of WSF of diesel and biodiesel on D. magna.


Assuntos
Biocombustíveis/toxicidade , Gasolina/toxicidade , Poluentes Químicos da Água/análise , Aliivibrio fischeri/efeitos dos fármacos , Animais , Daphnia/efeitos dos fármacos , Daphnia/crescimento & desenvolvimento , Ecotoxicologia/métodos
19.
Ecotoxicol Environ Saf ; 169: 918-927, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30597792

RESUMO

Extensive commercial use of aromatic hydrocarbons results with significant amounts of these chemicals and related by-products in waters, causing a severe ecological and health threat, thus requiring an increased attention. This study was aimed at developing models for prediction of the initial toxicity of the aromatic water-pollutants (expressed as EC50 and TU0) as well as the toxicity of their intermediates at half-life of the parent pollutant (TU1/2). For that purpose, toxicity toward Vibrio fischery was determined for 36 single-benzene ring compounds (S-BRCs), diversified by the type, number and position of substituents. Quantitative structure-activity relationship (QSAR) methodology paired with genetic algorithm optimization tool and multiple linear regression was applied to obtain the models predicting the targeted toxicity, which are based on pure structural characteristics of the tested pollutants, avoiding thus additional experimentation. Upon derivation of the models and extensive analysis on training and test sets, 4-, 4- and 5-variable models (for EC50 and TU0, TU1/2, respectively) were selected as the most predictive possessing 0.839

Assuntos
Aliivibrio fischeri/efeitos dos fármacos , Hidrocarbonetos Aromáticos/toxicidade , Modelos Teóricos , Raios Ultravioleta , Poluentes Químicos da Água/toxicidade , Meia-Vida , Hidrocarbonetos Aromáticos/química , Hidrocarbonetos Aromáticos/efeitos da radiação , Cinética , Valor Preditivo dos Testes , Relação Quantitativa Estrutura-Atividade , Poluentes Químicos da Água/química , Poluentes Químicos da Água/efeitos da radiação
20.
Chemosphere ; 215: 793-799, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30352376

RESUMO

Hormesis is a biphasic dose-response model with low-dose stimulation and high-dose inhibition. The mechanism for hormesis remains inconclusive, although it is becoming a central concept in toxicology. In this paper, the hormetic mechanism of sulfachloropyridazine (SCP) on Aliivibrio fischeri (A. fischeri) luminescence was explored by investigating into the interference of SCP with the bacterial quorum sensing (QS) communications. It was revealed that the SCP-induced hormesis on luminescence was due to its action on LitR - a key protein that connects lux and ain QS communications in A. fischeri. It was suggested SCP acted on LitR proteins to change its active forms, which subsequently induced hormetic effects on luxR (QS signal receptor) and thereby the luminescence. It is the first time that the hormetic mechanism based on bacterial QS was proposed, which provides a novel insight into the essence of the hormesis on A. fischeri luminescence.


Assuntos
Aliivibrio fischeri/efeitos dos fármacos , Proteínas de Bactérias/metabolismo , Comunicação Celular/efeitos dos fármacos , Hormese/efeitos dos fármacos , Luminescência , Percepção de Quorum/efeitos dos fármacos , Sulfonamidas/farmacologia , Aliivibrio fischeri/crescimento & desenvolvimento , Relação Dose-Resposta a Droga , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA