Browsing by Author "Melo, A."
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- Application of chemometric methods to assess the impact of intensive horticulture practices on groundwater content of nitrates, sodium, potassium and pesticidesPublication . Pinto, E.; Melo, A.; Aguiar, A.; Mansilha, C.; Pinho, O.; Ferreira, I.
- Emergence of the Asian lineage of Zika virus in Angola: an outbreak investigationPublication . Hill, S.C.; Vasconcelos, J.; Neto, Z.; Jandondo, D.; Zé-Zé, L.; Aguiar, R.S.; Xavier, J.; Thézé, J.; Mirandela, M.; Micolo Cândido, A.L.; Vaz, F.; Sebastião, C.D.S.; Wu, C.H.; Kraemer, M.U.G.; Melo, A.; Schamber-Rei, B.L.F.; de Azevedos, G.S.; Tanuri, T.; Higa, L.M.; Clemente, C.; da Silva, S.P.; da Silva Candido, D.; Claro, I.M.; Quibuco, D.; Domingos, C.; Pocongo, B.; Watts, A.G.; Khan, K.; Alcantara, L.C.J.; Sabino, E.C.; Lackritz, E.; Pybus, O.G.; Alves, M.J.; Afonso, J.; Faria, N.R.Background: Zika virus infections and suspected microcephaly cases have been reported in Angola since late 2016, but no data are available about the origins, epidemiology, and diversity of the virus. We aimed to investigate the emergence and circulation of Zika virus in Angola. Methods: Diagnostic samples collected by the Angolan Ministry of Health as part of routine arboviral surveillance were tested by real-time reverse transcription PCR by the Instituto Nacional de Investigação em Saúde (Ministry of Health, Luanda, Angola). To identify further samples positive for Zika virus and appropriate for genomic sequencing, we also tested samples from a 2017 study of people with HIV in Luanda. Portable sequencing was used to generate Angolan Zika virus genome sequences from three people positive for Zika virus infection by real-time reverse transcription PCR, including one neonate with microcephaly. Genetic and mobility data were analysed to investigate the date of introduction and geographical origin of Zika virus in Angola. Brain CT and MRI, and serological assays were done on a child with microcephaly to confirm microcephaly and assess previous Zika virus infection. Findings: Serum samples from 54 people with suspected acute Zika virus infection, 76 infants with suspected microcephaly, 24 mothers of infants with suspected microcephaly, 336 patients with suspected dengue virus or chikungunya virus infection, and 349 samples from the HIV study were tested by real-time reverse transcription PCR. Four cases identified between December, 2016, and June, 2017, tested positive for Zika virus. Analyses of viral genomic and human mobility data suggest that Zika virus was probably introduced to Angola from Brazil between July, 2015, and June, 2016. This introduction probably initiated local circulation of Zika virus in Angola that continued until at least June, 2017. The infant with microcephaly in whom CT and MRI were done had brain abnormalities consistent with congenital Zika syndrome and serological evidence for Zika virus infection. Interpretation: Our analyses show that autochthonous transmission of the Asian lineage of Zika virus has taken place in Africa. Zika virus surveillance and surveillance of associated cases of microcephaly throughout the continent is crucial.
- Emerging water contaminantsPublication . Mansilha, C.; Melo, A.; Ferreira, I.; Domingues, V.; Pinho, C.; Rocha, S.; Gameiro, P.
- Groundwater from infiltration galleries used for small public water supply systems: contamination with pesticides and endocrine disruptorsPublication . Mansilha, C.; Melo, A.; Ferreira, I.; Pinho, O.; Domingues, V.; Pinho, C.; Gameiro, P.Infiltration galleries are among the oldest known means used for small public water fountains. Owing to its ancestral origin they are usually associated with high quality water. Thirty-one compounds, including pesticides and estrogens from different chemical families, were analysed in waters from infiltration galleries collected in Alto Douro Demarcated Wine region (North of Portugal). A total of twelve compounds were detected in the water samples. Nine of these compounds are described as presenting evidence or potential evidence of interfering with the hormone system of humans and wildlife. Although concentrations of the target analytes were relatively low, many of them below their limit of quantification, four compounds were above quantification limit and two of them even above the legal limit of 0.1 μg/L: dimethoate (30.38 ng/L), folpet (64.35 ng/L), terbuthylazine-desethyl (22.28 to 292.36 ng/L) and terbuthylazine (22.49 to 369.33 ng/L).
- Impact of intensive horticulture practices on groundwater content of nitrates, sodium, potassium, and pesticidesPublication . Melo, A.; Pinto, E.; Aguiar, A.; Mansilha, C.; Pinho, O.; Ferreira, I.A monitoring program of nitrate, nitrite, potassium, sodium, and pesticides was carried out in water samples from an intensive horticulture area in a vulnerable zone from north of Portugal. Eight collecting points were selected and water-analyzed in five sampling campaigns, during 1 year. Chemometric techniques, such as cluster analysis, principal component analysis (PCA), and discriminant analysis, were used in order to understand the impact of intensive horticulture practices on dug and drilled wells groundwater and to study variations in the hydrochemistry of groundwater. PCA performed on pesticide data matrix yielded seven significant PCs explaining 77.67% of the data variance. Although PCA rendered considerable data reduction, it could not clearly group and distinguish the sample types. However, a visible differentiation between the water samples was obtained. Cluster and discriminant analysis grouped the eight collecting points into three clusters of similar characteristics pertaining to water contamination, indicating that it is necessary to improve the use of water, fertilizers, and pesticides. Inorganic fertilizers such as potassium nitrate were suspected to be the most important factors for nitrate contamination since highly significant Pearson correlation (r = 0.691, P < 0.01) was obtained between groundwater nitrate and potassium contents. Water from dug wells is especially prone to contamination from the grower and their closer neighbor's practices. Water from drilled wells is also contaminated from distant practices.
- In vitro bioacessibility and transport across Caco-2 monolayers of haloacetic acids in drinking waterPublication . Melo, A.; Faria, M.A.; Pinto, E.; Mansilha, C.; Ferreira, I.M.P.L.V.O.Water disinfection plays a crucial role in water safety but it is also a matter of concern as the use of disinfectants promotes the formation of disinfection by-products (DBPs). Haloacetic acids (HAAs) are one of the major classes of DBPs since they are frequently found in treated water, are ubiquitous, pervasive and have high water solubility, so a great concern emerged about their formation, occurrence and toxicity. Exposure to HAAs is influenced by consumption patterns and diet of individuals thus their bioavailability is an important parameter to the overall toxicity. In the current study the bioacessibility of the most representative HAAs (chloroacetic acid - MCAA, bromoacetic acid - MBAA, dichloroacetic acid - DCAA, dibromoacetic acid - DBAA, and trichloroacetic acid - TCAA) after simulated in vitro digestion (SIVD) in tap water and transport across Caco-2 monolayers was evaluated. Compounds were monitored in 8 points throughout the digestion phases by an optimized LC-MS/MS methodology. MCAA and MBAA were not bioaccessible after SIVD whereas DCAA, DBAA and TCAA are highly bioaccessible (85 ± 4%, 97 ± 4% and 106 ± 7% respectively). Concerning transport assays, DCAA and DBAA were highly permeable throughout the Caco-2 monolayer (apparent permeability and calculated fraction absorbed of 13.62 × 10(-6) cm/s and 90% for DCAA; and 8.82 × 10(-6) cm/s and 84% for DBAA), whereas TCAA showed no relevant permeability. The present results may contribute to efficient risk analysis studies concerning HAAs oral exposure from tap water taking into account the different biological behaviour of these chemically similar substances.
- Influence of dietary patterns on contaminants bioaccessibility and intestinal transport by in vitro assaysPublication . Faria, M.A.; Melo, A.; Ferreira, Isabel I.M.P.L.V.O.Food contaminants are usually studied as isolated molecules, not considering the overall meal components. Notwithstanding, contaminants are not ingested individually, therefore their risks should be assessed in the context of the overall diet. In the present study the influence of three well known dietary patterns, Western (W), Mediterranean (M) and vegetarian (V), on the bioaccessibility and intestinal transport of polycyclic aromatic hydrocarbons (PAHs) (benzo[a]pyrene (BaP) and benzo[b]fluoranthene (BbF)), heterocyclic aromatic amines (HAAs) (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-Amino-9H-pyrido[2,3-b]indole (AAC)) and mycotoxins (MY) (aflatoxin B2 (AB2) and ochratoxin A (OTA)) was evaluated. Whole meals representative of W, M and V patterns were spiked with 100 µg kg-1 of each contaminant and subjected to the Infogest in vitro digestion method. Intestinal transport was performed using Caco-2 cells in apical/basolateral inserts. Contaminants were quantified by QuEChERS/HPLC/Fluorescence analysis. The dietary pattern itself influenced significantly the bioaccessibility of some contaminants, since higher bioaccessibility of HAAs (PhIP and AAC) was observed for V diet, while higher bioaccessibility of PAHs (BBF and BAP) and the MY (OTA) was observed for W diet. Concerning intestinal transport, the effect of the diet matrices was less noticed. Notwithstanding, AAC transport increased with W diet, while AB2s transport increased with the V diet. Regarding PAHs the three patterns either blocked (BbF) or reduced (BaP) the transport. Besides the well known nutritional, protective or deleterious effects of the different dietary patterns, the increased bioaccessibility or intestinal transport of some food contaminants, can have an additional influence on the global health impact.
- Optimisation of a solid-phase microextraction/HPLC/Diode Array method for multiple pesticide screening in lettucePublication . Melo, A.; Aguiar, A.; Mansilha, C.; Pinho, O.; Ferreira, I.A new method was developed for the determination of 10 pesticides widely used in lettuce production (acetamiprid, azoxystrobin, cyprodinil, fenhexamid, fludioxonil, folpet, iprodione, metalaxyl, pirimicarb, and tolyfluanid) using solid-phase microextraction (SPME) and liquid chromatography (HPLC) with diode-array detection (DAD). The extraction performance of four different SPME coatings, polydimethylsiloxane (PDMS), PDMS/divinylbenzene (PDMS/DVB), carbowax/templated resin (CW/TPR), and polyacrylate (PA) was evaluated using an interface SPME–HPLC. CW/TPR fibre was selected as the most appropriate for the extraction of majority of these pesticides. Three variables (pH, NaCl% and extraction time) were considered key factors in the optimisation process. Interactions between these analytical factors and their optimal levels were investigated by response surface methodology based on central composite design. The method allowed the determination of azoxystrobin, cyprodinil, fenehexamid, fludioxonil, folpet, iprodione, and tolyfluanid in lettuce at concentrations between 0.8 and 25.6 mg/kg, i.e., bellow the maximum residues levels allowed for those compounds in lettuce. Lettuce samples that suffered pesticide treatments with folpet and fenehexamid were analysed during days to harvest to study the dissipation behaviour of the pesticides used. Concentration of folpet was 92.8; 53.4; 22.9; 17.9; 7.45; 1.85 mg/kg and concentration of fenhexamid was 158.1; 76.2; 31.0; 27.3; 7.24; 0.87 mg/kg, respectively for t0, t1, t3, t6, t7, t9 days, and not detected at t14 days for the two pesticides.
- Quantification of endocrine disruptors and pesticides in water by gas chromatography-tandem mass spectrometry. Method validation using weighted linear regression schemesPublication . Mansilha, C.; Melo, A.; Rebelo, H.; Ferreira, I.M.; Pinho, O.; Domingues, V.; Pinho, C.; Gameiro, P.A multi-residue methodology based on a solid phase extraction followed by gas chromatography-tandem mass spectrometry was developed for trace analysis of 32 compounds in water matrices, including estrogens and several pesticides from different chemical families, some of them with endocrine disrupting properties. Matrix standard calibration solutions were prepared by adding known amounts of the analytes to a residue-free sample to compensate matrix-induced chromatographic response enhancement observed for certain pesticides. Validation was done mainly according to the International Conference on Harmonisation recommendations, as well as some European and American validation guidelines with specifications for pesticides analysis and/or GC-MS methodology. As the assumption of homoscedasticity was not met for analytical data, weighted least squares linear regression procedure was applied as a simple and effective way to counteract the greater influence of the greater concentrations on the fitted regression line, improving accuracy at the lower end of the calibration curve. The method was considered validated for 31 compounds after consistent evaluation of the key analytical parameters: specificity, linearity, limit of detection and quantification, range, precision, accuracy, extraction efficiency, stability and robustness.
- Quantification of endocrine disruptors and pesticides in water using weighted linear regression schemesPublication . Melo, A.; Mansilha, C.; Pinho, O.; Ferreira, I.