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- Optimization of QuEChERS method for the analysis of organochlorine pesticides in soils with diverse organic matterPublication . Correia-Sá, Luísa; Fernandes, Virgínia C.; Carvalho, Manuela; Calhau, Conceição; Domingues, Valentina F.; Delerue-Matos, CristinaA QuEChERS method has been developed for the determination of 14 organochlorine pesticides in 14 soils from different Portuguese regions with wide range composition. The extracts were analysed by GC-ECD (where GC-ECD is gas chromatography-electron-capture detector) and confirmed by GC-MS/MS (where MS/MS is tandem mass spectrometry). The organic matter content is a key factor in the process efficiency. An optimization was carried out according to soils organic carbon level, divided in two groups: HS (organic carbon>2.3%) and LS (organic carbon<2.3%). Themethod was validated through linearity, recovery, precision and accuracy studies. The quantification was carried out using a matrixmatched calibration to minimize the existence of the matrix effect. Acceptable recoveries were obtained (70–120%) with a relative standard deviation of ≤16% for the three levels of contamination. The ranges of the limits of detection and of the limits of quantification in soils HS were from 3.42 to 23.77 μg kg−1 and from 11.41 to 79.23 μg kg−1, respectively. For LS soils, the limits of detection ranged from 6.11 to 14.78 μg kg−1 and the limits of quantification from 20.37 to 49.27 μg kg−1. In the 14 collected soil samples only one showed a residue of dieldrin (45.36 μg kg−1) above the limit of quantification. This methodology combines the advantages of QuEChERS, GC-ECD detection and GC-MS/MS confirmation producing a very rapid, sensitive and reliable procedure which can be applied in routine analytical laboratories.
- An uncertainty and sensitivity analysis applied to the prioritisation of pharmaceuticals as surface water contaminants from wastewater treatment plant direct emissionsPublication . Morais, Sérgio Alberto; Delerue-Matos, Cristina; Gabarrell, XavierIn this study, the concentration probability distributions of 82 pharmaceutical compounds detected in the effluents of 179 European wastewater treatment plants were computed and inserted into a multimedia fate model. The comparative ecotoxicological impact of the direct emission of these compounds from wastewater treatment plants on freshwater ecosystems, based on a potentially affected fraction (PAF) of species approach, was assessed to rank compounds based on priority. As many pharmaceuticals are acids or bases, the multimedia fate model accounts for regressions to estimate pH-dependent fate parameters. An uncertainty analysis was performed by means of Monte Carlo analysis, which included the uncertainty of fate and ecotoxicity model input variables, as well as the spatial variability of landscape characteristics on the European continental scale. Several pharmaceutical compounds were identified as being of greatest concern, including 7 analgesics/anti-inflammatories, 3 β-blockers, 3 psychiatric drugs, and 1 each of 6 other therapeutic classes. The fate and impact modelling relied extensively on estimated data, given that most of these compounds have little or no experimental fate or ecotoxicity data available, as well as a limited reported occurrence in effluents. The contribution of estimated model input variables to the variance of freshwater ecotoxicity impact, as well as the lack of experimental abiotic degradation data for most compounds, helped in establishing priorities for further testing. Generally, the effluent concentration and the ecotoxicity effect factor were the model input variables with the most significant effect on the uncertainty of output results.
- Assessment of groundwater contamination in an agricultural peri-urban area (NW Portugal): an integrated approachPublication . Barroso, M. Fátima; Ramalhosa, Maria João; Olhero, A.; Antão, M. C.; Pina, M. F.; Guimarães, L.; Teixeira, J.; Afonso, M. J.; Delerue-Matos, Cristina; Chaminé, Helder I.The excessive use of pesticides and fertilisers in agriculture has generated a decrease in groundwater and surface water quality in many regions of the EU, constituting a hazard for human health and the environment. Besides, on-site sewage disposal is an important source of groundwater contamination in urban and peri-urban areas. The assessment of groundwater vulnerability to contamination is an important tool to fulfil the demands of EU Directives. The purpose of this study is to assess the groundwater vulnerability to contamination related mainly to agricultural activities in a peri-urban area (Vila do Conde, NW Portugal). The hydrogeological framework is characterised mainly by fissured granitic basement and sedimentary cover. Water samples were collected and analysed for temperature, pH, electrical conductivity, chloride, phosphate, nitrate and nitrite. An evaluation of groundwater vulnerability to contamination was applied (GOD-S, Pesticide DRASTIC-Fm, SINTACS and SI) and the potential nitrate contamination risk was assessed, both on a hydrogeological GIS-based mapping. A principal component analysis was performed to characterised patterns of relationship among groundwater contamination, vulnerability, and the hydrogeological setting assessed. Levels of nitrate above legislation limits were detected in 75 % of the samples analysed. Alluvia units showed the highest nitrate concentrations and also the highest vulnerability and risk. Nitrate contamination is a serious problem affecting groundwater, particularly shallow aquifers, especially due to agriculture activities, livestock and cesspools. GIS-based cartography provided an accurate way to improve knowledge on water circulation models and global functioning of local aquifer systems. Finally, this study highlights the adequacy of an integrated approach, combining hydrogeochemical data, vulnerability assessments and multivariate analysis, to understand groundwater processes in peri-urban areas.
- Air pollution from traffic emissions in Oporto, Portugal: health and environmental implicationsPublication . Slezakova, Klara; Castro, Dionísia; Begonha, Arlindo; Delerue-Matos, Cristina; Alvim-Ferraz, Maria da Conceição M.; Morais, Simone; Pereira, Maria do CarmoAir pollution represents a serious risk not only to environment and human health, but also to historical heritage. In this study, air pollution of the Oporto Metropolitan Area and its main impacts were characterized. The results showed that levels of CO, PM10 and SO2 have been continuously decreasing in the respective metropolitan area while levels of NOx and NO2 have not changed significantly. Traffic emissions were the main source of the determined polycyclic aromatic hydrocarbons (PAHs; 16 PAHs considered by U.S. EPA as priority pollutants, dibenzo[a,l]pyrene and benzo[j]fluoranthene) in air of the respective metropolitan area. The mean concentration of 18 PAHs in air was 69.9±39.7 ng m−3 with 3–4 rings PAHs accounting for 75% of the total ΣPAHs. The health risk analysis of PAHs in air showed that the estimated values of lifetime lung cancer risks considerably exceeded the health-based guideline level. Analytical results also confirm that historical monuments in urban areas act as passive repositories for air pollutants present in the surrounding atmosphere. FTIR and EDX analyses showed that gypsum was the most important constituent of black crusts of the characterized historical monument Monastery of Serra do Pilar classified as “UNESCO World Cultural Heritage”. In black crusts, 4–6 rings compounds accounted approximately for 85% of ΣPAHs. The diagnostic ratios confirmed that traffic emissions were the major source of PAHs in black crusts; PAH composition profiles were very similar for crusts and PM10 and PM2.5.
- Synergistic and antibiofilm properties of ocellatin peptides against multidrug-resistant Pseudomonas aeruginosaPublication . Bessa, Lucinda J; Eaton, Peter; Dematei, Anderson; Plácido, Alexandra; Vale, Nuno; Gomes, Paula; Delerue-Matos, Cristina; Leite, José Roberto Sá; Gameiro, PaulaAim:To test ocellatin peptides (ocellatins-PT2-PT6) for antibacterial and antibiofilm activities and synergy with antibiotics against Pseudomonas aeruginosa. Materials & methods: Normal- and checkerboard-broth microdilution methods were used. Biofilm studies included microtiter plate-based assays and microscopic analysis by confocal laser scanning microscopy and atomic force microscopy. Results: Ocellatins were more active against multidrug-resistant isolates of P. aeruginosa than against susceptible strains. Ocellatin-PT3 showed synergy with ciprofloxacin and ceftazidime against multidrug-resistant isolates and was capable of preventing the proliferation of 48-h mature biofilms at concentrations ranging from 4 to 8× the MIC. Treated biofilms had low viability and were slightly more disaggregated. Conclusion: Ocellatin-PT3 may be promising as a template for the development of novel antimicrobial peptides against P. aeruginosa.
- Biosensor for direct bioelectrocatalysis detection of nitric oxide using nitric oxide reductase incorporated in carboxylated single-walled carbon nanotubes/lipidic 3 bilayer nanocompositePublication . Gomes, Filipa O.; Maia, Luísa B.; Loureiro, Joana A.; Pereira, Maria Carmo; Delerue-Matos, Cristina; Moura, Isabel; Moura, José J.G.; Morais, SimoneAn enzymatic biosensor based on nitric oxide reductase (NOR; purified from Marinobacter hydrocarbonoclasticus) was developed for nitric oxide (NO) detection. The biosensor was prepared by deposition onto a pyrolytic graphite electrode (PGE) of a nanocomposite constituted by carboxylated single-walled carbon nanotubes (SWCNTs), a lipidic bilayer [1,2-di-(9Z-octadecenoyl)-sn-glycero-3-phosphoethanolamine (DOPE), 1,2-di-(9Z-octadecenoyl)-3-trimethylammonium-propane (DOTAP), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol (DSPE-PEG)] and NOR. NOR direct electron transfer and NO bioelectrocatalysis were characterized by several electrochemical techniques. The biosensor development was also followed by scanning electron microscopy and Fourier transform infrared spectroscopy. Improved enzyme stability and electron transfer (1.96 × 10-4 cm.s-1 apparent rate constant) was obtained with the optimum SWCNTs/(DOPE:DOTAP:DSPE-PEG)/NOR) ratio of 4/2.5/4 (v/v/v), which biomimicked the NOR environment. The PGE/[SWCNTs/(DOPE:DOTAP:DSPE-PEG)/NOR] biosensor exhibited a low Michaelis-Menten constant (4.3 μM), wide linear range (0.44-9.09 μM), low detection limit (0.13 μM), high repeatability (4.1% RSD), reproducibility (7.0% RSD), and stability (ca. 5 weeks). Selectivity tests towards L-arginine, ascorbic acid, sodium nitrate, sodium nitrite and glucose showed that these compounds did not significantly interfere in NO biosensing (91.0 ± 9.3%-98.4 ± 5.3% recoveries). The proposed biosensor, by incorporating the benefits of biomimetic features of the phospholipid bilayer with SWCNT's inherent properties and NOR bioelectrocatalytic activity and selectivity, is a promising tool for NO.
- Persistent organic pollutant levels in human visceral and subcutaneous adipose tissue in obese individuals - Depot differences and dysmetabolism implicationsPublication . Pestana, Diogo; Faria, Gil; Sá, Carla; Fernandes, Virgínia C.; Teixeira, Diana; Norberto, Sónia; Faria, Ana; Meireles, Manuela; Marques, Cláudia; Correia-Sá, Luísa; Cunha, Ana; Guimarães, João T.; Taveira-Gomes, António; Santos, Ana Cristina; Domingues, Valentina F.; Delerue-Matos, Cristina; Monteiro, Rosário; Calhau, ConceiçãoBackground: The role of persistent organic pollutants (POPs) with endocrine disrupting activity in the aetiology of obesity and other metabolic dysfunctions has been recently highlighted. Adipose tissue (AT) is a common site of POPs accumulation where they can induce adverse effects on human health. Objectives: To evaluate the presence of POPs in human visceral (vAT) and subcutaneous (scAT) adipose tissue in a sample of Portuguese obese patients that underwent bariatric surgery, and assess their putative association with metabolic disruption preoperatively, as well as with subsequent body mass index (BMI) reduction. Methods: AT samples (n=189) from obese patients (BMI ≥35) were collected and the levels of 13 POPs were determined by gas chromatography with electron-capture detection (GC-ECD). Anthropometric and biochemical data were collected at the time of surgery. BMI variation was evaluated after 12 months and adipocyte size was measured in AT samples. Results: Our data confirm that POPs are pervasive in this obese population (96.3% of detection on both tissues), their abundance increasing with age (RS=0.310, p<0.01) and duration of obesity (RS=0.170, p<0.05). We observed a difference in AT depot POPs storage capability, with higher levels of ΣPOPs in vAT (213.9±204.2 compared to 155.1±147.4 ng/g of fat, p<0.001), extremely relevant when evaluating their metabolic impact. Furthermore, there was a positive correlation between POP levels and the presence of metabolic syndrome components, namely dysglycaemia and hypertension, and more importantly with cardiovascular risk (RS=0.277, p<0.01), with relevance for vAT (RS=0.315, p<0.01). Finally, we observed an interesting relation of higher POP levels with lower weight loss in older patients. Conclusion: Our sample of obese subjects allowed us to highlight the importance of POPs stored in AT on the development of metabolic dysfunction in a context of obesity, shifting the focus to their metabolic effects and not only for their recognition as environmental obesogens.
- Towards a reliable technology for antioxidant capacity and oxidative damage evaluation: Electrochemical (bio)sensorsPublication . Barroso, M. Fátima; de-los-Santos-Álvarez, N.; Delerue-Matos, Cristina; Oliveira, M. Beatriz P. P.To counteract and prevent the deleterious effect of free radicals the living organisms have developed complex endogenous and exogenous antioxidant systems. Several analytical methodologies have been proposed in order to quantify antioxidants in food, beverages and biological fluids. This paper revises the electroanalytical approaches developed for the assessment of the total or individual antioxidant capacity. Four electrochemical sensing approaches have been identified, based on the direct electrochemical detection of antioxidant at bare or chemically modified electrodes, and using enzymatic and DNA-based biosensors.
- Multiplexed electrochemical immunosensor for detection of celiac disease serological markersPublication . Neves, Marta M. P. S.; González-García, María Begoña; Delerue-Matos, Cristina; Costa-García, AgustínCeliac disease (CD) is a gluten-induced autoimmune enteropathy characterized by the presence of antibodies against gliadin (AGA) and anti-tissue transglutaminase (anti-tTG) antibodies. A disposable electrochemical dual immunosensor for the simultaneous detection of IgA and IgG type AGA and antitTG antibodies in real patient’s samples is presented. The proposed immunosensor is based on a dual screen-printed carbon electrode, with two working electrodes, nanostructured with a carbon–metal hybrid system that worked as the transducer surface. The immunosensing strategy consisted of the immobilization of gliadin and tTG (i.e. CD specific antigens) on the nanostructured electrode surface. The electrochemical detection of the human antibodies present in the assayed serum samples was carried out through the antigen–antibody interaction and recorded using alkaline phosphatase labelled anti-human antibodies and a mixture of 3-indoxyl phosphate with silver ions was used as the substrate. The analytical signal was based on the anodic redissolution of enzymatically generated silver by cyclic voltammetry. The results obtained were corroborated with commercial ELISA kits indicating that the developed sensor can be a good alternative to the traditional methods allowing a decentralization of the analyses towards a point-of-care strategy.
- From soil to cosmetic industry: Validation of a new cosmetic ingredient extracted from chestnut shellsPublication . Pinto, Diana; de la Luz Cádiz-Gurrea, María; Garcia, Juliana; Saavedra, Maria José; Freitas, Vitor; Costa, Paulo; Sarmento, Bruno; Delerue-Matos, Cristina; Rodrigues, FranciscaSustainability arises as a challenge in the last decades and the cosmetic field is not an exception. The search for new cosmetic active principles extracted from food byproducts through eco-innovative technologies has emerged as a novel concept. However, the European Regulation is very restrictive and different assays should be performed to guarantee the products' efficacy and safety. Considering a multidisciplinary approach, this paper aims to compare chestnut shell extracts prepared by three different green techniques – Subcritical Water Extraction (SWE), Ultrasound-Assisted Extraction (UAE) and Supercritical Fluids Extraction (SFE) – regarding antimicrobial activity, hyaluronidase and elastase inhibitory activities, in-vitro cytotoxicity on dermal cells (HaCaT and HFF-1) and skin permeation (using Franz cells coupled to human skin). The best extract was tested on skin and ocular 3D models and through an in-vivo patch test to evaluate its irritancy and safety. The results demonstrated the antimicrobial properties of the extracts (particularly against Staphylococcus aureus) as well as the capacity to inhibit the hyaluronidase (IC50 = 0.76–54.36 mg/mL) and elastase (33.56–82.70% at 0.4 mg/mL) activities. Regarding in-vitro cell assays, UAE and SWE extracts revealed the best outcomes. Between 0.1 and 100 μg/mL, none of the extracts conducted to a decrease of cell viability in both cell lines (HaCaT and HFF-1). The ex-vivo assay proved that SWE extract led to a higher polyphenol's permeation (1061.6 μg/g dw), being selected for further assays. Ellagic acid was the major polyphenol that permeated the human skin (732.1–847.0 μg/g dw). The 3D skin and ocular models evidenced absence of irritation by SWE extract, without decreasing cell viability and releasing IL-1α. Finally, an in-vivo patch test confirmed the absence of irritation in humans based on the acute irritation index of 0.50 achieved 24 h after the patch removal. To the best of our knowledge, this is the first study that validated by in-vitro and in-vivo assays, and in accordance with the European Regulation 1223/2009, a new cosmetic ingredient extracted from chestnut shells.