"Wetlands: Water Living Filters?",

Human societies have indirectly used natural wetlands as wastewater discharge sites for many centuries. Observations of the wastewater depuration capacity of natural wetlands have led to a greater understanding of the potential of these ecosystems for pollutant assimilation and have stimulated the development of artificial wetlands systems for treatment of wastewaters from a variety of sources. Constructed wetlands, in contrast to natural wetlands, are human-made systems that are designed, built and operated to emulate wetlands or functions of natural wetlands for human desires or needs. Constructed wetlands have recently received considerable attention as low cost, efficient means to clean-up not only municipal wastewaters but also point and non-point wastewaters, such as acid mine drainage, agricultural effluents, landfill leachates, petrochemicals, as well as industrial effluents. Currently, untreated wastewater discharge in the natural wetlands sites is becoming an increasingly abandoned practice whereas the use of constructed wetlands for treatment of wastewater is an emerging technology worldwide. However, natural wetlands still play an important role in the improvement of water quality as they act as buffer zones surrounding water bodies and as a polishing stage for the effluents from conventional wastewater treatment plants, before they reach the receiving water streams. In fact, one of the emerging issues in environmental science has been the inefficiency of wastewater treatment plants to remove several xenobiotic organic compounds such as pesticides and pharmaceutical residues and consequent contamination of the receiving water bodies. Recent studies have shown that wetlands systems were able to efficiently remove many of these compounds, thus reaffirming the importance of the role which can be played by wetlands in water quality preservation. The aim of this work is to present a review on the application of wetlands as “living” filters for water purification, with special emphasis focused in the removal of micropollutants, especially xenobiotic organic compounds such as pharmaceuticals and pesticides residues, which are not efficiently removed by conventional wastewater treatment plants. Furthermore, the role of wetlands as protection zones which contribute to the improvement of the aquatic ecosystems’ quality will be discussed

Colóquio: Novos desafios alimentares para os países da CPLP: diagnóstico prospetivo

No âmbito do curso de Mestrado em Ciências do Consumo Alimentar (MCCA)/DCeT decorreu o Colóquio intitulado: "Novos desafios alimentares para os países da CPLP: diagnóstico prospetivo", contando com a participação do representante da FAO Portugal/CPLP, e da Ordem dos Nutricionistas, tendo sido parcialmente emitido na Emissão UAb n.º 110 (minutos:15:11-17:42 )N/

Role of microRNAs in the regulation of cardiovascular diseases : focus on remodelling

MicroRNAs (miRNAs) are a large class of noncoding RNAs that regulate the expression of protein-coding genes at the post-transcriptional level . They are recognized as regulators of biological processes underlying cardiovascular disorders including hypertrophy, ischemic heart disease, valvular disease and arrhythmias. Particularly, circulating miRNAs are promising biomarkers of cardiovascular pathology (1). MiRNAs are small, noncoding, RNA molecules with approximately 22 nucleotides in length, which act as post-transcriptional regulators of gene expression. Individual miRNAs have been demonstrated to negatively regulate the expression of multiple gene transcripts by the cleavage or suppression of translation of a target mRNA. Conversely, the expression of individual genes can be regulated by multiple miRNAs. Since their experimental description in 1993 (2), a large number of miRNAs known by their gene-regulatory roles in different biological processes, have been catalogued. In fact, miRNAs are known to regulate approximately one third of all coding gene transcripts in mammals, showing their importance as key process modulators (3). Regarding cardiovascular diseases, miRNAs have been identified as key regulators of complex biological processes linked to several conditions as presented above, including left ventricular remodelling, atherosclerosis and myocardial infarction, heart failure, hypertension and arrhythmias (1). miRNAs are expressed in the cardiovascular system, but their role in cardiovascular diseases has not yet been entirely clarified. Moreover, since the discovery that miRNAs are present in the circulation, they have been investigated as novel biomarker as presented bellow. Only 3% of the human genome codes for proteins. Nevertheless, while noncoding RNAs will not act for coding into proteins they modulate all genomic functions. These noncoding RNAs include short miRNAs with approximately 22 nucleotides) and longer, with >200 nucleotides, long noncoding RNAs (lncRNAs) with important biological functions (4) since they are now clearly recognised to play key roles in gene regulation and may simultaneously represent diagnostic and prognostic biomarkers in cardiovascular diseases. (5,6) there are in excess of 2000 human miRNAs (catalogued in mirBase (http://www.mirbase.org) (7). Of note, the key feature of the mechanism of action of miRNAs is that a single miRNA can regulate the expression of several genes, depending on the specificity of the target sequence. On the other side, individual genes can be regulated by different miRNAs particularly if they involve complementary sequences for more than one miRNA. These factors lead to a highly complex regulatory mechanism, often difficult to understand. (8,9). In the healthy adult heart, data from a large sequencing project and other sequential studies, has identified a number of miRNAs that are highly expressed in healthy cardiac tissue and thus expected to play a key role in both normal cardiac function and disease. (10,11) These include miR-1, miR-16, miR-27b, miR-30d, miR-126, miR-133, miR-143, miR-208 and the let-7 family. However, many others have been identified and are now under study. The concept of miRNA-based therapeutics has been emerging and under development, with synthetic antagonists of miRNAs (antagomiRs or antimirs) and very promising in animal models but awaiting new advances in phase II human trials, still in its infancy (12,13). miRNAs clearly intervene in physiological and pathological processes in the cardiovascular diseases. We will review miRNA biology and its role on LV remodeling in myocardial infarction, heart failure, hypertension and aortic stenosis as additionally a note will be provided on the potential of miRNAs for therapeutics.info:eu-repo/semantics/publishedVersio

Pilot-scale study on the removal of pharmaceuticals by LECA based SSF-constructed wetlands

In recent years, the occurrence and fate of pharmaceutically active compounds (PhACs) in the aquatic environment has been recognized as one of the emerging issues in environmental chemistry. Some compounds are just resistant to degradation in the sewage treatment plants (STPs) while others, although suffering partial degradation, still end up in receiving water bodies due to the large inputs received in STPs [1]. Clofibric acid (a metabolite from a series of widely used blood lipids lowering agents), ibuprofen (an anti-inflamatory non-prescription drug) and carbamazepine (an anticonvulsant and mood stabilizing drug) are some of the most frequently found PhACs in environmental monitoring studies [1]. Wastewater treatment by sub-surface flow constructed wetland systems (SSF-CWs) is a low-cost technology that has shown some capacity for removal of several organic xenobiotic pollutants, but fewer studies exist on pharmaceuticals behavior. The aim of the present work was to evaluate the efficiency of a pilot SSF-CW assembled with the plants cattail (Typha spp.) and a clay material (LECA 2/4) as support matrix, for the removal of three pharmaceuticals, namely ibuprofen (IB), carbamazepine (CB) and clofibric acid (CA), from contaminated wastewaters. Four beds were planted with pre-grown cattails (density of 80 plants/m2) and four were left unplanted to be used as controls. Experiments were conducted both in batch and in continuous mode with a flooding rate of 100%. Pharmaceutical concentrations were quantified by HPLC with UV detection at 210 nm (CB), 222 nm (IB) and 230 nm (CA). Solid phase extraction was used for sample pre-concentration whenever the measured pharmaceutical concentrations fell under the limit of quantification of the analytical method. The physico-chemical characterization of the support matrix material, LECA, involved the determination of properties such as pH, point of zero charge, electrical conductivity, apparent porosity, bulk density and hydraulic conductivity. In order to shed some light on the tolerance mechanisms developed by Typha spp. in the presence of these pharmaceuticals, biochemical and physiological parameters were evaluated. Typha spp. showed good tolerance to the presence of CA, CB and IB concentrations of 1 mg L-1, which is a value much higher than those usually reported in wastewaters. LECA alone was able to remove about 90% of the initial amounts of CB and IB in solution, and 50% of CA. IB was very susceptible to microbial degradation and up to 80% of the initial concentration could be removed by the microbial population present in the wastewater used. Overall, the CWS shows a higher removal performance for CA, CB and IB than any of its individual components (plants, support matrix, microorganisms) considered separately. CA proved to be the most resilient compound, which comes in agreement with other published data. However, this system enabled the removal of substantially higher amounts of CA than has previously been reported in other studies. The use of systems of this kind for the removal of pharmaceuticals from wastewaters seems like a promising alternative to the less efficient processes of conventional wastewater treatment

Using clay materials to remove pharmaceuticals from waters

Pharmaceutical active compounds (PhACs) have an important role in the treatment and prevention of disease in both human and animals. Ingested drugs are only partially absorbed by the organisms and studies have shown that the excreted compounds are only partially removed in the sewage treatment plants (STPs) [1]. Contaminated effluents are being released from the STPs and trace amounts of PhACs have been detected in wastewaters, surface and groundwaters worldwide [1]. Acidic pharmaceuticals like diclofenac, ibuprofen and clofibric acid are some of the most frequently detected compounds [1]. The concentrations detected are low (ng/L - μg/L) but, due to the very nature of these compounds, studies have shown damaging effects on the aquatic ecosystems [1]. Several different processed natural materials can be used as filter media in water and wastewater treatment systems. Some of these materials can additionally present functions which extend beyond the simple process of filtration. Their surface areas can constitute a support for microbial population growth in biofilters as well as support matrix for the development of macrophytes in sub-surface flow constructed wetland systems (SSF-CWS) [2] which are increasingly being used in sewage tertiary treatment. The efficiency of these biological systems in the removal of xenobiotics can be significantly enhanced by a greater capability of the support matrix to retain contaminants by sorption phenomena, ionic exchange or other physico-chemical processes [2]. The aim of the present work was to evaluate the efficiency of two different materials namely, Light Expanded Clay Aggregates [LECA] (in two different particle sizes) and sand, for the removal from water of three acidic PhACs, clofibric acid, diclofenac and ibuprofen. In addition, relationships were established between the compounds removal efficiencies and the physico-chemical properties of each material. A series of batch essays were carried out to study the sorption capacities of the different materials for the 3 chemical compounds. The influence of some experimental conditions, such as the contact time, the initial PhACs concentrations (1 mg/L up to 50 mg/L) and LECA particle size, were investigated. The media were sterilized before use in order to minimize any microbial development on the matrix and experiments were conducted in the dark to avoid any photocatalytic degradation reactions. The mineralogical composition of the materials was determined by X-ray diffraction and some physico-chemical properties were characterized. Samples of the contaminants’ aqueous solutions were collected over a range of contact times with the support matrix and the remaining concentrations in solution were determined by UV/Vis spectrophotometry. The results show that LECA has a good sorption capacity for acidic compounds. In contrast, sand does not exhibit any sorption capacity for any of the compounds tested. Not surprisingly, LECA with smaller particle sizes show higher efficiencies that larger grade LECA, due to a larger available surface area. However, the use of these smaller particle media at upper scales may present problems with hydraulic conductivities. From the results obtained, it can be concluded that expanded clay presents important advantages as a CWS support matrix or as a filter medium, because it has a good sorption capacity, a pH buffer capacity and an excellent control of hydraulic permeability. On the other hand, sand does not exhibit any sorption capacity that might enhance the performance of filters and CWS in the treatment of water contaminated with this type of contaminants

Sorption behavior of granular matrices for application in pharmaceutical removal by SSF constructed wetlands

In recent years, the occurrence and fate of pharmaceutically active compounds (PhACs) in the aquatic environment has been recognized as one of the emerging issues in environmental chemistry. Clofibric acid, ibuprofen and carbamazepine are some of the most frequently found PhACs in environmental monitoring studies. Some xenobiotics have already been successfully removed from contaminated waters using constructed wetlands (CW). Depuration of wastewaters in CWs is achieved by the concerted action between plant rhizomes, microorganisms and matrix component. CWs efficiency can be significantly improved by careful selection of the matrix, plants and microorganism used. Among several physico-chemical phenomena, sorption by the matrix plays an important role in the PhACs removal mechanism. It is important to select a matrix with a high sorption capacity, which depends on the physico-chemical properties of the material chosen. Previous studies carried out by the authors showed that expanded clay (LECA) presents a high sorptive affinity by clofibric acid [1]. The aim of the present work was to evaluate the capacity of LECA to remove other PhACs, namely ibuprofen and carbamazepine, and compare the results obtained with these pharmaceuticals with those obtained previously with clofibric acid. In addition, other materials were tested for the removal of clofibric acid and the results were compared with those obtained with LECA. The ultimate objective of this work will be to optimize the performance of this component in the overall performance of a constructed wetlands system designed for the removal of PhACs from wastewaters

Removal of pharmaceuticals in constructed wetlands using Typha and LECA. A pilot-scale study.

An ever-increasing number of xenobiotic compounds are getting detected in environmental samples worldwide. Serious concern about the contamination of water resources and drinking water supplies has aroused from the prevalence of pharmaceutical residues in the aquatic ecosystems. Some pharmaceuticals such as ibuprofen, carbamazepine and clofibric acid are frequently detected in waters [1]. These compounds are generally quantified at low concentrations (at the ng/L or mg/L range) but, due to their persistence in the environment and to potentially cumulative effects in the organisms, studies have shown that these compounds can have some damaging effects on the aquatic ecosystems [1]. Several xenobiotic organic compounds have already been removed from contaminated waters using constructed wetlands (CW) where the processes occurring in natural wetlands can be optimized in engineered man-made ecosystems, specifically designed for wastewater treatment. Among several physico-chemical phenomena, sorption by the support matrix plays an important role in the contaminant removal mechanisms. It is important to select a matrix with a high sorption capacity, which will depend on the physico-chemical properties of the material chosen. Previous studies have shown that expanded clay (LECA) is capable to remove, by sorption, this type of substances from water [2]. CWs also take advantage of the ability of plants to adsorb, uptake and concentrate pollutants, as well as to release root exudates that enhance compound biotransformation and degradation. Wetland species such as the cattail (Typha spp.) have already been tested and found suitable for the removal of several organic compounds from wastewaters, being commonly used in CWs [3]. The aim of the present work was to evaluate the efficiency of a subsurface flow constructed wetland assembled with the plants Typha spp. and LECA as support matrix, for the removal of three pharmaceuticals, namely ibuprofen, carbamazepine and clofibric acid, from contaminated waters

Removing pharmaceutical residues from contaminated wastewaters using expanded clay aggregates

Pharmaceutical compounds (PhCs) are ingested in large quantities by humans in treatment and prevention of disease, but they are only partially absorbed by the organisms being excreted together with their metabolites. The sewage treatment plants (STP) are only able to partially remove some of these compounds and, despite the low concentrations present in the wastewaters (ng-μg/L), these xenobiotics can still pose a serious threat to the aquatic environments. Sub-surface flow constructed wetland systems (SSF-CWS) are biological systems used in wastewater treatment, and clay materials can be used as support matrices for these systems. Clay materials act not only as filters but they also can potentially remove organic pollutants due to its sorption properties. In this study a processed clay material, light expanded clay aggregates (LECA), was tested for their sorption capacity towards three widespread water polluting pharmaceuticals, namely clofibric acid (CA), ibuprofen (IB) and carbamazepine (CB). Sorption assays were done with aqueous solutions of the individual compounds and with their mixture at different concentrations from 1.0 to 50.0 mg L-1. The sorptive properties of LECA were also investigated using wastewater spiked with a mixture of the three compounds at the same concentrations tested for the aqueous solutions. Reversed phase HPLC with UV-Vis detection at 210, 222 and 227 nm for CB, IB and CA respectively was used to measure the compounds concentrations. For the single-compound solutions the HPLC analyses were performed in isocratic mode with a mobile phase composed by 75:25 acetonitrile:water with 0.1% (v/v) phosphoric acid. For the solutions containing the three compounds, the separation was performed using the same elution solvents and a gradient program. The total run time was 8 minutes, the flow rate was 1.0 mL min-1 and the injection volume was 20 µL. Calibration curves were constructed for standard solutions of CB, IB and CA individually, as well as solutions containing the three mixed compounds. The average areas of the compounds’ peaks were plotted against the standards concentrations resulting in linear correlations with R2 equal to or higher than 0.999 in every calibration curve. Whenever the measured concentrations were below the method’s LOQs of 0.27 mg L-1, 0.39 mg L-1 and 0.13 mg L-1 for CB, IB and CA respectively, the samples were pre-concentrated on LiChrolut® RP-18. All data were analyzed by the analysis of variance method (ANOVA, single factor) at different significance levels. Results for the individual compounds in aqueous solutions have shown that LECA presents higher removal rates for IB and CB (44 – 92% and 60 – 95% respectively) whereas for CA the removal rates are moderate but still significant (30– 58%). In any case, and for all the studied compounds, the % removal decreased with the increasing load, the lower % removal still correspond to increasing absolute amounts sorbed. When the three compounds are put simultaneously in contact with LECA there are evidences of competitive sorption among the studied compounds, with CB being the less affected compound of the three. When all the compounds were dissolved in wastewater, there was a slight loss of removal efficiency, probably due to an increased solubility in the aqueous media owing to the organic matter present in the wastewater or to competitive sorption effects. Considering the hydraulic and physico-chemical properties of LECA which make this material suitable for constructed wetlands applications, its sorption properties evidenced in this work make it especially interesting for applications aiming at the removal of this kind of pollutants from wastewaters

Study on the use of Typha spp. for the phytotreatment of water contaminated with ibuprofen

Several studies on phytotoxic effects caused by organic xenobiotics and their removal from water by macrophytes have already been performed to evaluate the usefulness of these plants for phytoremediation technologies. In this context, a study was conducted to assess Typha spp.’s ability to withstand and remove, from water, the non-steroidal anti-inflammatory drug ibuprofen. For an initial ibuprofen concentration of 20 mgL 1, Typha removed nearly 60% of it within the first 24 h, attaining over 99% removal by the end of the assay (21 days). Exposure to higher ibuprofen concentrations did affect Typha’s growth but, by the end of the assays, plants’ growth as well as photosynthetic pigments approached normal values. An alteration in antioxidant enzymes activities (superoxide dismutase, catalase, guaiacol peroxidase) indicated that both roots and leaves were affected by the xenobiotic. Eventually, Typha seemed able to cope with ibuprofen’s induced oxidative damage suggesting its ability for phytotreatment of waters contaminated with ibuprofen