Browsing by Author "Pedro, Paulo"
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- Are the defined substrate-based methods adequate to determine the microbiological quality of natural recreational waters?Publication . Valente, Marta Sofia; Pedro, Paulo; Carmen Alonso, M.; Borrego, Juan J.; Dionísio, LídiaMonitoring the microbiological quality of water used for recreational activities is very important to human public health. Although the sanitary quality of recreational marine waters could be evaluated by standard methods, they are time-consuming and need confirmation. For these reasons, faster and more sensitive methods, such as the defined substrate-based technology, have been developed. In the present work, we have compared the standard method of membrane filtration using Tergitol-TTC agar for total coliforms and Escherichia coli, and Slanetz and Bartley agar for enterococci, and the IDEXX defined substrate technology for these faecal pollution indicators to determine the microbiological quality of natural recreational waters. ISO 17994: 2004 standard was used to compare these methods. The IDEXX for total coliforms and E. coli, Colilert (R), showed higher values than those obtained by the standard method. Enterolert (R) test, for the enumeration of enterococci, showed lower values when compared with the standard method. It may be concluded that more studies to evaluate the precision and accuracy of the rapid tests are required in order to apply them for routine monitoring of marine and freshwater recreational bathing areas. The main advantages of these methods are that they are more specific, feasible and simpler than the standard methodology.
- Assessment of Iodine Deficiency in Sao Tome e Principe ChildrenPublication . Serafim, Angela; Martins-Ferreira, Ana; Serafim, P.; Pedro, Paulo; Rodrigues, Celia; Coutinho, Miguel; Figueiredo, TeresaIntroduction: Iodine deficiency still constitutes one of the major public health problems in the world, having a serious social and economic impact. This global problem involves about 130 countries, including Sao Tome and Principe (STP). The aim of the present study was to determine the prevalence and distribution of iodine deficiency in male children within different host institutions of STP. Material and Methods: A descriptive, cross-sectional observational study was conducted with a non-probabilistic sample (for convenience) of 116 children. Children were aged from 6 to 17 years, with an overall mean age of 11.1 +/- 3.2 years. Iodine intake was evaluated in 6 districts of STP, through two indirect indices: (i) urine iodine (UI) determinations (ii) prevalence of goiter evaluated by cervical ultrasound. Results: The global median UI value was 109 mu g/L (P20: 78.2 mu g/Land P80: 140.3 mu g/L), with 16.4% of children <50 mu g/L and 40.5% <100 mu g/L. Considering children aged 6 - 12 years, 15.6% showed U1 <50 mu g / L, while in group aged 13-17 years this percentage increased to 17.9%. These values fulfill WHO criteria of sufficient region in iodine. On the other hand, the goiter prevalence against age was 29.7% and against Body Surface Area (BSA) was 44.6%, which is much higher than the cut-off established by the WHO (5%). Conclusion: The iodine deficiency and endemic goiter in STP are currently a public health problem. Therefore, it will be necessary to ensure that the interventions carried out are efficiently monitored, in order to eradicate endemic goiter, without risks of hyperthyroidism.
- Influence of particle size on ecotoxicity of low-density polyethylene microplastics, with and without adsorbed benzo-a-pyrene, in Clam Scrobicularia planaPublication . Rodrigues, Ana Rita; Mestre, Nélia; FONSECA, TAINÁ; Pedro, Paulo; Carteny, Camilla C.; Cormier, Bettie; Keiter, Steffen; Bebianno, Maria JoãoThis study investigated the ecotoxicological effects of differently sized (4–6 µm and 20–25 µm) low-density polyethylene (LDPE) microplastics (MPs), with and without adsorbed benzo-a-pyrene (BaP), in clam Scrobicularia plana. Biomarkers of oxidative stress (superoxide dismutase—SOD; catalase—CAT), biotransformation (glutathione-S-transferases—GST), oxidative damage (lipid peroxidation—LPO) and neurotoxicity (acetylcholinesterase—AChE) were analysed in gills and digestive glands at different time intervals for a total of 14 days of exposure. In order to have a better impact perspective of these contaminants, an integrated biomarker response index (IBR) and Health Index were applied. Biomarker alterations are apparently more related to smaller sized (4–6 µm) MPs in gills and to virgin LDPE MPs in the digestive gland according to IBR results, while the digestive gland was more affected by these MPs according to the health index.
- Perfluorooctane sulfonic acid (PFOS) adsorbed to polyethylene microplastics: accumulation and ecotoxicological effects in the clam Scrobicularia planaPublication . Islam, Naimul; FONSECA, TAINÁ; Vilke, Juliano Marcelo; Gonçalves, Joanna M.; Pedro, Paulo; Keiter, Steffen; Cunha, Sara C.; Fernandes, José O.; Bebianno, Maria JoãoMicroplastics are widespread in the marine environment, whereby organisms’ uptake these tiny particles, presenting adverse biological responses. Plastic debris also act as a vector of many contaminants which intensify their effects to marine organisms that depend on type, size, shape and chemical properties. This study aimed to assess the accumulation and potential toxicity of different sizes of microplastics with and without adsorbed perfluorooctane sulfonic acid (PFOS) in the clam Scrobicularia plana. Clams were exposed to 1 mg L-1 of virgin and PFOS (70.2 ± 12.4 μg g−1) contaminated lowdensity polyethylene microplastics of two different sizes (4-6 and 20-25 μm) over 14 days. Microplastic and PFOS accumulation and filtration rate were determined along with a multi biomarker approach to access the biological effects of microplastics accumulation. Biomarkers include oxidative stress (superoxide dismutase, catalase, glutathione peroxidases), biotransformation enzymes (glutathione-S-transferases) activity, neurotoxicity (acetylcholinesterase activity), oxidative damage and apoptosis. Microplastics and PFOS accumulated were microplastic size dependent but not PFOS dependent and filtration rate was reduced at the end of the exposure. Reactive oxygen species in gills and digestive gland were generated as a result of exposure to both types of microplastics, confirming the disturbance of the antioxidant system. Larger microparticles lead to stronger impacts, when compared to smaller ones which was also supported by Integrated Biomarker Responses index calculated for both tissues. An anti-apoptotic response was detected in digestive glands under exposure to any of the MPs treatments as a probable mechanism associated to carcinogenic responses derived from MPs uptake.
- Photocatalytic composite nanomaterial and engineering solution for inactivation of airborne bacteriaPublication . Danilenko, Igor; Gorban, Oksana; Pedro, Paulo; Viegas, Joao; Shapovalova, Olesya; Akhkozov, Leonid; Konstantinova, Tetyana; Lyubchyk, SvitlanaIn this study we propose a new composite material with an enhanced bactericidal action that utilises the complex interactions with bacteria: mechanical interactions of the bacteria with ZnO tetrapod spikes, a photocatalytic process on ZnO nanoparticles, and disinfection by Ag nanoparticles. ZnO and Ag nanoparticles were immobilised on a single-crystalline ZnO tetrapod by the ultrasonic mixing method. The XRD, TEM, SEM and EDS analyses showed the tetrapod-like crystals covered by ZnO and Ag nanoparticles. This complex photocatalytic material, deposited on a grid support, was tested in the UV purifier air system in the AR Diagnostic company. The active microbial monitoring of the indoor air showed a decrease in the concentration of bacteria in the air of the meeting room, with the door open, at 90% for a duration of 30-40 min. A simple variant of the design of an air purifier system, which can be mounted in different types of air channels and compartments, is proposed.
- Postglacial sea-level rise in South Portugal as recorded in Guadiana EstuaryPublication . Boski, T.; Moura, Delminda; Camacho, Sarita; Duarte, Duarte; Scott, David; Veiga-Pires, C.; Pedro, Paulo; Santana, PauloThe Guadiana River Estuary is located in the terminal part of a deeply incised river valley, which accumulated several tens of meters of sediments during the Holocenic transgression. Five cored boreholes (see Fig.1 for localisation) that reached the pre-Holocenic substratum were drilled recently in order to recognize the architecture of sedimentary facies and to quantify the accumulation of organic carbon trapped in sediments during the valley infilling by marine waters. It was assumed that due to structural constraints imposed by Palaeozoic and Mezozoic substratum, the main estuarine channel did not change its position significantly. Consequently borehole locations were chosen in order to represent different sedimentary environments in the estuary: proximity to the main channel (CM1 and CM3), external sea facing (CM4) and lagoonal (CM2 and CM5) environments.
- Preenchimento sedimentar em três estuários do Algarve durante o HolocénicoPublication . Boski, T.; Moura, Delminda; Veiga-Pires, C.; Duarte, Duarte; Santana, Paulo; Pedro, PauloAs bacias hidrográficas são distintas quer do ponto de vista hidrológico quer na forma e àrea de captação.
- A subida do nível do mar durante o Holocénico no Golfo de Cadiz – tendência regional e diferenças locaisPublication . Moura, Delminda; Boski, T.; Duarte, Duarte; Veiga-Pires, C.; Pedro, Paulo; Lourenço, Nuno; Diniz, FilomenaIn Guadiana River Estuary, the Holocene sequence is underlain by pebbly delta fan formed in two stages, prior to 5E and 3 highstands. The Holocene sedimentary sequence was lain either directly on gravels or on top of fluvial sands deposited between 11000 and 10000 yr. BP. An accelerated phase of infilling of the estuary by clayey sediments, containing marsh foraminifer Trochammina, began at ca. 9800 yr. BP when the sea level was about 39 m below the present.At ca. 7000 BP the central part of the estuary started to accommodate coarser sediments, partially introduced from the shelf. The first phase of the Holocene sea level rise at a rate of 0.85 m/century terminated at ca 6500yr. BP. Since then, the lagoonal bodies in the vicinity of estuary started to enclose behind sand spits and predominantly sandy sedimentation initiated within the estuary. After the second phase of a slower rise at the rate of 0.3 m/century, which lasted until ca. 5000 yr.BP, the sea approached the present level. Data from Guadalete Estuary published in Spain set the beginning of Holocene transgression at shallower level (ca 10m)than in Guadiana Estuary.This discrepancy may be explained by isostatic uplift of Betic Cordillera or slumping of Guadiana terrace on which the Holocene sediments are lain. Since 7500 yr. BP the data from Odiel-Tinto, Guadalete and Guadiana are in a relatively good agreement.