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In this work, the Fenton technology was applied to decolorize methylene blue (MB) and to inactivate Escherichia coli K12, used as recalcitrant compound and bacteria models respectively, in order to provide an approach into single and combinative effects of the main process variables influencing the Fenton technology. First, Box&ndash, Behnken design (BBD) was applied to evaluate and optimize the individual and interactive effects of three process parameters, namely Fe2+ concentration (6.0 &times, 10&minus, 4, 8.0 &times, 4 and 1.0 &times, 3 mol/L), molar ratio between H2O2 and Fe2+ (1:1, 2:1 and 3:1) and pH (3.0, 4.0 and 5.0) for Fenton technology. The responses studied in these models were the degree of MB decolorization (D%MB), rate constant of MB decolorization (kappMB) and E. coli K12 inactivation in uLog units (IuLogEC). According to the results of analysis of variances all of the proposed models were adequate with a high regression coefficient (R2 from 0.9911 to 0.9994). BBD results suggest that [H2O2]/[Fe2+] values had a significant effect only on D%MB response, [Fe2+] had a significant effect on all the responses, whereas pH had a significant effect on D%MB and IuLogEC. The optimum conditions obtained from response surface methodology for D%MB ([H2O2]/[Fe2+] = 2.9, [Fe2+] = 1.0 &times, 3 mol/L and pH = 3.2), kappMB ([H2O2]/[Fe2+] = 1.7, [Fe2+] = 1.0 &times, 3 mol/L and PH = 3.7) and IuLogEC ([H2O2]/[Fe2+] = 2.9, [Fe2+] = 7.6 &times, 4 mol/L and pH= 3.2) were in good agreement with the values predicted by the model.

The use of constructed wetlands as a wastewater treatment system is a feasible solution for rural areas. However, these systems do not efficiently eliminate pathogenic microorganisms. Therefore, it is necessary to implement disinfection systems such as ultraviolet (UV) disinfection systems in constructed wetlands. To evaluate the behavior of a UV system, a pilot system of artificial wetlands connected to one such disinfection system was operated. The results show that when the total suspended solids (TSS) of the influent (already treated by the system of constructed wetlands) reached values of 26.7 mg/L, a reduction of 2.03 uLog in fecal coliforms was obtained. However, when the TSS increased to 34.7 mg/L, the reduction was only 0.33 uLog. In addition to the influence of the TSS on the fecal coliform reduction efficiency, there is a direct relationship between the transmittance and the sizes of the particles present in the influent. After UV treatment, the microorganisms showed a peak in photoreactivation of 27.8% at 4 h after irradiation with visible radiation, while under conditions of darkness, no reactivation was observed.

The green synthesis of nanoparticles allows for obtaining nanomaterials using plant extracts, avoiding the use of toxic and dangerous chemical compounds. The aim of this study was to evaluate the effect of phenolic compounds in plant extracts on the synthesis of iron oxide nanoparticles (FexOy-NPs) with photocatalytic activity. Accordingly, the phenolic content in 11 plant extracts was evaluated by the Folin–Ciocalteu (F–C) method, and the iron-reducing capacity was evaluated by the ferric-reducing antioxidant power method (FRAP). From the F–C and FRAP analyses, the Luma apiculata (LAL), Phragmites australis (PAL) and Eucalyptus globulus (EGL) extracts were selected and analyzed by HPLC coupled with a diode array detector (DAD) to identify and quantify the phenolic compounds. Using the three selected extracts, FexOy-NPs were synthesized, which were then characterized by UV–Vis spectroscopy, FTIR, DLS, zeta potential, SEM-EDX, and Raman and diffuse reflectance spectroscopy. The SEM-EDX, DLS and zeta potential analyses showed that the FexOy-NPs were spherical, stable and nanosized. The FRAP, F–C and FTIR analyses indicated the role of phenolic compounds in the formation and stabilization of FexOy-NPs. It was possible to establish a direct relationship between the composition of the phenolic compounds and the reducing capacity of the extracts. In addition, it was found that phenolic compounds and their concentrations are associated with the size and type of FexOy-NPs obtained. Furthermore, it was proposed that types of phenolic compounds influence the formation of different phases of FexOy-NPs. The photocatalytic activity of the FexOy-NPs was demonstrated by diffuse reflectance spectroscopy and decolorization of a dye under visible radiation.

In recent decades, the alteration of coastal food webs (via aquaculture, fishing, and leisure activities), nutrient loading, and an expansion of monitoring programs have prompted an apparent worldwide rise in Harmful Algae Blooms (HABs). Over this time, a parallel increase in HABs has also been observed in the Chilean southern austral region (Patagonia fjords). HAB species like Alexandrium catenella—responsible for Paralytic Shellfish Poisoning (PSP)—are of great public concern due to their negative socioeconomic impacts and significant northward geographical range expansion. Many toxic dinoflagellate species (like A. catenella) produce benthic resting cysts, yet a holistic understanding of the physical-chemical and biological conditions influencing the distributions of cysts in this region is lacking. In this study, we measured a combination of hydrographic (temperature, salinity, and dissolved oxygen) and sediment physical-chemical properties (temperature, pH and redox potential), in addition to meiofaunal abundances –as sediment bioturbators and potential cyst predators– to determine the factors influencing dinoflagellate cyst distribution, with emphasis on A. catenella in and around a “hotspot” area of southern Chile. An analysis of similarities (ANOSIM) test revealed significant differences (p

Amitriptyline (AMT) is the most widely used tricyclic antidepressant and is classified as a recalcitrant emergent contaminant because it has been detected in different sources of water. Its accumulation in water and soil represents a risk for different living creatures. To remove amitriptyline from wastewater, the Advanced Oxidation Processes (AOPs) stands up as an interesting option since generate highly oxidized species as hydroxyl radicals ( OH) by environmentally friendly mechanism. In this work, the oxidation and mineralization of AMT solution have been comparatively studied by 3 Electrochemical AOPs (EAOPs) where the OH is produced by anodic oxidation of H2O (AO-H2O2), or by electro-Fenton (EF) or photoelectro-Fenton (PEF). PEF process with a BDD anode showed the best performance for degradation and mineralization of this drug due to the synergistic action of highly reactive physiosorbed BDD ( OH), homogeneous OH and UVA radiation. This process achieved total degradation of AMT at 50 min of electrolysis and 95% of mineralization after 360 min of treatment with 0.5 mmol L−1 Fe2+ at 100 mA cm−2. Six aromatic intermediates for the drug mineralization were identified in short time of electrolysis by GC-MS, including a chloroaromatic by-product formed from the attack of active chlorine. Short-chain carboxylic acids like succinic, malic, oxalic and formic acid were quantified by ion-exclusion HPLC. Furthermore, the formation of NO3− ions was monitored. Finally, the organic intermediates identified by chromatographic techniques were used to propose the reaction sequence for the total mineralization of AMT.

This study reports on the kinetics of the early steps that mediate the reactions of substituted 1,2-dihydroxybenzenes (1,2-DHB) with Fe3+. The rate constants of the three processes identified by means of the stopped-flow technique are affected by the electron-withdrawing or electron-donating abilities of the substituent. The fastest process is assigned to the formation of a 1:1 complex between Fe3+ and the 1,2-DHB, which is accompanied by proton loss. The second process involves the inner-sphere electron transfer from the ligand to Fe3+ and the slowest step is related to the deprotonation of one of the oxygen atoms bonded to the metal. A reaction mechanism is proposed on the basis of the experimental data and density functional theory (DFT) calculations on mono- and bidentate species with different degrees of protonation. Fil: Salgado, Pablo. Universidad de Concepción; Chile Fil: Contreras, David. Universidad de Concepción; Chile Fil: Mansilla, Héctor D.. Universidad de Concepción; Chile Fil: Márquez, Katherine. Universidad de Concepción; Chile Fil: Vidal, Gladys. Universidad de Concepción; Chile Fil: Cobos, Carlos Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina Fil: Martire, Daniel Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina

The dinoflagellate Alexandrium catenella is responsible for paralytic shellfish poisoning and negative socioeconomic impacts on the fishing industry and aquaculture. In Chilean Patagonia, the reasons underlying the significant increase in the geographical extension (from south to north) of A. catenella blooms during the last five decades are not well understood. To assess the potential spreading risk of A. catenella during an intense austral summer bloom, we conducted an in situ experiment in a "hotspot" of this dinoflagellate in southern Chile. The objective was to assess the accumulation of A. catenella resting cysts in passive (fishing nets) and active (mussels) dispersal agents during the phase of bloom decline. Large numbers of resting cysts were detected in fishing nets (maximum of 5334 cysts net−1 per month) at 5 m depth and in mussels (maximum of 16 cysts g−1 of digestive gland) near Vergara Island. The potential of these vectors to serve as inoculum sources and the implications of our findings for A. catenella population dynamics are discussed.

Exposure of white wine to oxygen can cause detrimental effects, such as loss of sensorial characteristics. New antecedents, to the oxidation of wine, establish the importance of the formation of metallic complexes with compounds with adjacent hydroxyls. These complexes could reduce iron, promoting the formation of radicals through the Fenton reaction. The formation of hydroxyl radical (OH) induced by air was found in all 18 white wines analysed by electronic paramagnetic resonance (EPR) spectroscopy. The variation in the OH production was related to the phenolic composition of the wines. The amount of these radicals was linearly related to 5 phenolic compounds (caffeic acid, protocatechuic acid, p-coumaric acid, gentisic acid and syringic acid). Therefore, in this study, the relationship between certain phenolic compounds and the induction and amplification of the OH production was established and was postulated to be a chemical oxidation pathway to the Fenton reaction.

12 pages, 5 figures, 1 table.-- This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited, The family Ceratocoryaceae includes the genera Ceratocorys, Protoceratium, and Schuettiella, whose phylogenetic relationships are poorly known. Here, the new non-yessotoxin-producing species of the genus Ceratocorys, Ceratocorys mariaovidiorum sp. nov., previously reported as the toxic Protoceratium reticulatum, is described from examinations by light and scanning electron microscopy, molecular phylogeny, and toxin analyses. The species description is made from culture samples of strains CCMP1740 and CCMP404 from USA waters. Ceratocorys mariaovidiorum is globular and has thick and strongly reticulated plates with one pore within each reticule, just like P. reticulatum, but the key difference between the two species is the presence of five precingular plates in C. mariaovidiorum instead of six as in P. reticulatum. The thecal plate formula is Po, 40, 0a, 5″, 6c, ~7s, 5‴, 0p, 20000. The apical pore plate is oval with a k-shaped pore. The first apical plate is narrow with a ventral pore on the right anterior side; it contacts the apical pore plate and its contact with the anterior sulcal plate is slight or absent. The fourth precingular plate of other Gonyaulacales is absent. Ceratocorys mariaovidiorum may have small spines on the second antapical plate. A phylogenetic study based on internal transcribed spacer/5.8SrDNA supports the morphological classification of C. mariaovidiorum as a new species of Ceratocorys and in a different clade from P. reticulatum, The present study is a contribution of the Unidad Asociada “Microalgas Nocivas” (CSIC–IEO) that was carried out at the Instituto Espa~nol de Oceanograf ıa (IEO) in Vigo and funded by the CCVIEO project, the Spanish National Project CICAN (CGL2013-40671-R) and CIGUATROP Spanish project funded by Fundaci on Biodiversidad. This article will be part of the doctoral thesis of Pablo Salgado and is within the doctoral program “Marine Science, Technology and Management” (DO*MAR) of the University of Vigo. P. Salgado is a researcher at the Instituto de Fomento Pesquero (IFOP), which has provided financial support for his doctoral stay at the IEO in Vigo

Asexual and sexual life cycle events were studied in cultures of the toxic marine dinoflagellate Protoceratium reticulatum. Asexual division by desmoschisis was characterized morphologically and changes in DNA content were analyzed by flow cytometry. The results indicated that haploid cells with a C DNA content occurred only during the light period whereas a shift from a C to a 2C DNA content (indicative of S phase) took place only during darkness. The sexual life cycle was documented by examining the mating type as well as the morphology of the sexual stages and nuclei. Gamete fusion resulted in a planozygote with two longitudinal flagella, but longitudinally biflagellated cells arising from planozygote division were also observed, so one of the daughter cells retained two longitudinal flagella while the other daughter cell lacked them. Presumed planozygotes (identified by their longitudinally biflagellated form) followed two life-cycle routes: division and encystment (resting cyst formation). Both the division of longitudinally biflagellated cells and resting cyst formation are morphologically described herein. Resting cyst formation through sexual reproduction was observed in 6.1% of crosses and followed a complex heterothallic pattern. Clonal strains underwent sexuality (homothallism for planozygote formation and division) but without the production of resting cysts. Ornamental processes of resting cysts formed from the cyst wall under an outer balloon-shaped membrane and were fully developed in

A planktonic-benthic relationship has been described for many dinoflagellate species as part of their ecological strategy to overcome highly variable aquatic environments. Here, the phylogenetically and morphologically related marine dinoflagellates Protoceratium reticulatum and Ceratocorys mariaovidiorum were studied in relation to an unknown benthic life form. In vivo and fixed samples from cultures were analyzed in detail by light and scanning electron microscopy. In both species, a cell type with a morphology different from that of vegetative cells was observed in cultures grown until stationary phase. This cell type was always benthic, swimming sporadically only when it was disturbed. Its main feature included a strong dorsoventral compression. These cells originated from vegetative cells whose protoplasm underwent a progressive flattening, resulting in a gradual detachment of the reticulate and thick thecal plates and the formation of very thin non-reticulated new plates with pores. When returned to fresh full-strength medium, the cells recovered their spherical vegetative-like morphology, including new reticulated thick plates and subsequent cell divisions. The kinetics of flattened cell formation showed that in both species, this cell type increased exponentially until the onset of the culture stationary phase and then decreased. The results of this study are discussed in the context of the planktonic–benthic coupling in dinoflagellate life cycles, including those newly appreciated to be well adapted to the benthic environment.

Fenton systems are interesting alternatives to advanced oxidation processes (AOPs) applied in soil or water remediation. 1,2-Dihydroxybenzenes (1,2-DHBs) are able to amplify the reactivity of Fenton systems and have been extensively studied in biological systems and for AOP applications. To develop efficient AOPs based on Fenton systems driven by 1,2-DHBs, the change in reactivity mediated by different 1,2-DHBs must be understood. For this, a systematic study of the reactivity of Fenton-like systems driven by 1,2-DHBs with different substituents at position 4 was performed. The substituent effect was analyzed using the Hammett constant (σ), which has positive values for electron-withdrawing groups (EWGs) and negative values for electron-donating groups (EDGs). The reactivity of each system was determined from the degradation of a recalcitrant azo dye and hydroxyl radical (HO·) production. The relationship between these reactivities and the ability of each 1,2-DHB to reduce Fe(III) was determined. From these results, we propose two pathways for HO· production. The pathway for Fenton-like systems driven by 1,2-DHBs with EDGs depends only on the Fe(III) reduction mediated by 1,2-DHB. In Fenton-like reactions driven by 1,2-DHBs with EWGs, the Fe(III) reduction is not primarily responsible for increasing the HO· production by this system in the early stages.

Quistes de resistencia del dinoflagelado potencialmente toxico Lingulodinium polyedrum (Stein) Dodge son registrados por primera vez en sedimentos costeros del Mar Interior de Chiloe. Se entrega informacion de abundancia, distribucion, descripcion y fotomicrografias de la especie. Se confirma la presencia de L. polyedrum en aguas costeras del sur de Chile.

19 páginas, 6 tablas, 4 figuras.-- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited, Alexandrium ostenfeldii is present in a wide variety of environments in coastal areas worldwide and is the only dinoflagellate known species that produces paralytic shellfish poisoning (PSP) toxins and two types of cyclic imines, spirolides (SPXs) and gymnodimines (GYMs). The increasing frequency of A. ostenfeldii blooms in the Baltic Sea has been attributed to the warming water in this region. To learn more about the optimal environmental conditions favoring the proliferation of A. ostenfeldii and its complex toxicity, the effects of temperature and salinity on the kinetics of both the growth and the net toxin production of this species were examined using a factorial design and a response-surface analysis (RSA). The results showed that the growth of Baltic A. ostenfeldii occurs over a wide range of temperatures and salinities (12.5–25.5°C and 5–21, respectively), with optimal growth conditions achieved at a temperature of 25.5°C and a salinity of 11.2. Together with the finding that a salinity > 21 was the only growth-limiting factor detected for this strain, this study provides important insights into the autecology and population distribution of this species in the Baltic Sea. The presence of PSP toxins, including gonyautoxin (GTX)-3, GTX-2, and saxitoxin (STX), and GYMs (GYM-A and GYM-B/-C analogues) was detected under all temperature and salinity conditions tested and in the majority of the cases was concomitant with both the exponential growth and stationary phases of the dinoflagellate’s growth cycle. Toxin concentrations were maximal at temperatures and salinities of 20.9°C and 17 for the GYM-A analogue and > 19°C and 15 for PSP toxins, respectively. The ecological implications of the optimal conditions for growth and toxin production of A. ostenfeldii in the Baltic Sea are discussed, This work is a contribution of the Unidad Asociada "Microalgas Nocivas" (CSIC-IEO) and was financially supported by the CCVIEO project and CICAN-2013-40671-R (Ministry of Economy and Competitiveness). P. Salgado is a researcher at IFOP, which has provided financial support for his doctoral stay