Browsing by Author "Mansilha, Catarina"
Now showing 1 - 10 of 25
Results Per Page
Sort Options
- Acute and chronic toxicity assessment of haloacetic acids using Daphnia magnaPublication . Melo, Armindo; Ferreira, Cláudia; Ferreira, Isabel M.P.L.V.O.; Mansilha, CatarinaHaloacetic acids (HAAs) are undesirable disinfection by-products (DBPs), released into aquatic ecosystems from various anthropogenic and natural sources. The aim of this study was to examine the ecological risk of exposure to three HAAs commonly detected in water, such as monobromoacetic acid (MBA), monochloroacetic acid (MCA), and trichloroacetic acid (TCA), in in vivo acute and chronic toxicity tests using Daphnia magna as a model. Acute tests showed that MBA was the most toxic of these compounds followed by MCA and TCA as evidenced by immobilization. Aquatic organisms in natural conditions might be exposed simultaneously to numerous compounds; thus, binary mixtures of selected HAAs and a ternary mixture of these were tested. Concentration addition (CA) and independent action (IA) models were used for a predictive assessment of mixture toxicity. Data demonstrated that CA appeared to be the most reliable indicator for HAAs binary and ternary mixtures suggestive of an additive behavior. Median effective concentration (EC50) values from the mixed exposure tests were significantly lower than results obtained from single tests for all three HAAs where an increase of toxicity greater than 50%. Multigenerational chronic tests were also performed exposing daphnids to the ternary mixture of HAAs. A markedly decreased sexual maturity and number of offspring and broods per daphnid especially in the second generation were noted.
- Analysis of Pesticides in Tomato Combining QuEChERS and Dispersive Liquid–Liquid Microextraction Followed by High-Performance Liquid ChromatographyPublication . Melo, Armindo; Mansilha, Catarina; Pinho, Olívia; Ferreira, Isabel M.P.L.V.O.A new sample preparation procedure combining QuEChERS and dispersive liquid–liquid microextraction (DLLME) was optimized for the determination at trace levels of 13 pesticides from different chemical families (i.e. 2,4-D, acetamiprid, bentazone, cymoxanil, deltamethrin, dicamba, diuron, foramsulfuron, mesotrione, metalaxyl- M, methomyl, pyraclostrobin and tembotrione) in tomato by high-performance liquid chromatography with diode array detection. Target pesticides from tomato samples were isolated by liquid partitioning with acetonitrile and salts and cleaned up by dispersive solid-phase extraction (d-SPE); the analytes were concentrated in trichloromethane by the DLLME procedure. The disperser solvent from DLLME was used at the same time as carrier of analytes form extraction in QuEChERS method. The main factors affecting sample cleanup by d-SPE in QuEChERS and DLLME yield were optimized by means of an experimental design.Under the optimum conditions, good linearity was obtained, the recoveries of pesticides in tomato samples at spiking levels between 0.01 and 1.00 mg/kg ranged from 86 to 116 % (for foramsulfuron and cymoxanil, respectively). Precision was within 15.0 % (RSD) except at the LQ for tembotrione, which was 17.4 %. Limits of quantification achieved (ranging from 0.0058 to 0.15 mg/kg) were below the maximum residue limits established by the European Union.
- Analysis of total extractable hydrocarbons in environmental water samples. Implementation and validation of a FT-IR methodPublication . Pinho, Carina; Melo, Armindo; Mansilha, Catarina; Gameiro, Paula
- Avaliação da Qualidade de águas subterrâneas: estudo de alguns parâmetros físico-químicosPublication . Mansilha, Catarina; Rebelo, HelenaA água subterrânea é um recurso natural valioso que, enquanto tal, deve ser protegido da deterioração e da poluição química. Essa proteção é particularmente importante no que respeita aos ecossistemas dela dependentes e à sua utilização para o abastecimento de água destinada ao consumo humano1. O sector do abastecimento de água em Portugal é um serviço público essencial e insubstituível com grande impacte no bem-estar geral dos cidadãos, na saúde pública, nas atividades económicas e na proteção do ambiente. Serve atualmente cerca de 94% da população portuguesa2, sendo caracterizado por uma grande diversidade em termos dos modelos de gestão, com uma entrada crescente de operadores e de capital estrangeiro3. Atendendo, no entanto, à atual conjetura económica do país e ao panorama tarifário no setor da água e do saneamento, tem vindo a aumentar o consumo de água subterrânea por parte das populações, principalmente em zonas rurais, que recorrem cada vez com maior frequência a furos e poços, bem como a águas de minas e nascentes, para uso doméstico. De acordo com o estudo “Água e Saneamento em Portugal: o Mercado e os Preços” apresentado em Novembro de 2012 pela APDA, e noticiado no jornal Público de 28/11/2012, nos últimos três anos tem vindo a diminuir o consumo de água comprada às empresas ou serviços de abastecimento. Tal tendência tem sido igualmente verificada nos nossos Laboratórios de análise de águas do Porto e Lisboa, verificando-se um aumento do número de pedidos de análise de águas subterrâneas destinadas a consumo humano por particulares. Têm surgido igualmente, com alguma frequência, amostras de poços e furos de captações ilegais e ainda amostras resultantes da mistura de água não tratada com água da rede pública. Torna-se portanto essencial avaliar a potabilidade destas águas, preferencialmente através de análises regulares, uma vez que, mesmo sem sinais visíveis de contaminação a água pode estar poluída, em especial se entre os locais de captação e consumo existem zonas agrícolas, industrializadas ou com fossas séticas, constituindo a ausência de controlo um problema real, capaz de gerar situações muito complexas de saúde pública. Em termos Regulamentares, a qualidade da água para consumo humano segue o disposto no Decreto-Lei n.º 306/2007 de 27 de Agosto, que tem por objetivo proteger a saúde humana dos efeitos nocivos resultantes da eventual contaminação da água e assegurar a disponibilização tendencialmente universal de água salubre, limpa e desejavelmente equilibrada. No respeitante à água subterrânea, o Decreto-Lei n.º 208/2008 de 28 de Outubro estabelece o regime de proteção das águas subterrâneas contra a poluição e deterioração, transpondo para a ordem jurídica interna a Diretiva n.º 2006/118/CE, do Parlamento Europeu e do Conselho, de 12 de Dezembro, relativa à proteção da água subterrânea contra a poluição e deterioração, e regulamenta o artigo 47.º da Lei n.º 58/2005, de 29 de Dezembro (Lei da Água) referente à avaliação do estado químico da água subterrânea. Refere este Decreto que tendo em conta a necessidade de obter níveis de proteção da água subterrânea, dever-se-ão cumprir os critérios já fixados para 2 poluentes (nitratos e pesticidas) e estabelecer normas de qualidade e limiares para um conjunto de outros parâmetros pertinentes (poluentes, grupos de poluentes e indicadores de poluição) que contribuem para que as massas de águas subterrâneas corram o risco de não cumprirem os objetivos da Diretiva-Quadro da Água4. Neste último caso, o estabelecimento de valores numéricos a nível comunitário não foi considerado uma opção viável, devido à grande variabilidade natural de substâncias presentes nas águas subterrâneas (em função das condições hidrogeológicas, das concentrações de fundo geoquímico, dos trajetos dos poluentes e das interações com diversos compartimentos ambientais), exigindo-se que os Estados-Membros estabeleçam as suas próprias normas de qualidade, tendo em conta os riscos identificados e a lista de poluentes/indicadores constante do anexo II da Diretiva 2006/118/CE5. Da lista mínima de poluentes e dos respetivos indicadores para os quais os Estados-Membros têm de considerar a fixação de limiares constam: (a) Substâncias ou iões, ou indicadores, que podem ocorrer naturalmente ou como resultado de atividades humanas (Arsénio, Cádmio, Chumbo, Mercúrio, Azoto amoniacal, Cloreto, Sulfato); (b) Substâncias sintéticas artificiais (Tricloroetileno; Tetracloroetileno) e (c) Parâmetros indicativos de intrusões salinas ou outras (Condutividade / Cloreto, Sulfato). Alguns países estabeleceram já limiares, tendo fundamentalmente por base os padrões de água potável previstos na Diretiva UE (98/83/CE) ou respetivas normas nacionais.Este trabalho objetivou uma avaliação global da qualidade das águas subterrâneas, rececionadas nos nossos Laboratórios do Porto e Lisboa entre os anos de 2010 e 2012, no que respeita a alguns dos poluentes/indicadores referidos (nitratos, sulfatos, cloretos, azoto amoniacal, condutividade e pH) e sua adequação para fins domésticos. Foram analisadas um total de 1518 amostras provenientes de 17 distritos do País, e realizados estudos comparativos referentes a variações geográficas e sazonais.
- Avaliação da qualidade de águas subterrâneas: estudo de alguns parâmetros físico-químicosPublication . Mansilha, Catarina; Rebelo, Helena
- Bathing waters: new directive, new standards, new quality approachPublication . Mansilha, Catarina; Coelho, Carla; Heitor, Ana; Amado, João; Martins, Joaquim; Gameiro, PaulaBathing water quality is an important public health issue, mainly because of fecal contamination. In 2006, the European Commission (EC) adopted a new directive with respect to recreational bathing waters that calls for stricter standards and reduces the number of laboratory tests done in routine beach monitoring from nineteen to two bacterial indicators, namely, Escherichia coli and intestinal enterococci, replacing policies of the EC Bathing Water Directive that have existed since 1976. Our practice in Portugal is in line with this international development, and this study demonstrates the equivalency of the new bacteriological parameters with the old. The water quality of 25 coastal beaches was surveyed using both new and old microbiological indicators of fecal contamination. Statistical analysis demonstrated equivalency of the results obtained for fecal coliforms with Escherichia coli and for fecal streptococci with intestinal enterococci.
- Bisphenol A migration from plastic materials: direct insight of ecotoxicity in Daphnia magnaPublication . Mansilha, Catarina; Silva, Poliana; Rocha, Sónia; Gameiro, Paula; Domingues, Valentina; Pinho, Carina; Ferreira, IsabelBisphenol A (BPA) is an endocrine disrupting chemical (EDC) whose migration from food packaging is recognized worldwide. However, the real overall food contamination and related consequences are yet largely unknown. Among humans, children exposition to BPA contamination has been emphasized because the immaturity of their biological systems. The main aim of this study was to assess the reproductive burden of BPA leached from commercially available plastic containers used or related to child nutrition, performing ecotoxicological tests using the biomonitoring specie Daphnia magna. Acute and chronic tests, as well as single and multigenerational tests were done. Migration of BPA from several baby bottles and other plastic containers evaluated by GC-MS indicated that a broader range of foodstuff may be contaminated when packed in plastics. Ecotoxicological tests results performed using defined concentrations of BPA were in agreement with literature, although a precocious maturity of daphnids was detected at 3.0 mg/L. Curiously, an increased reproductive output (embryos per female) was observed when daphnids were bred in the polycarbonate (PC) containers (145.1±4.3% to 264.7±3.8%), both in single as in multigenerational tests, in comparison with the negative control group (100.3±1.6%). A strong correlated dose-dependent ecotoxicological effect was observed, providing evidence that BPA leached from plastic food packaging materials act as functional estrogen in vivo at very low concentrations. In contrast, embryo production by daphnids cultured in polypropylene and non-PC bottles, was slightly but not significantly enhanced (92.5±2.0% to 118.8±1.8%). Multigenerational tests also revealed magnification of the adverse effects, not only on fecundity but also on mortality, which represents a worrying trend for organisms that are chronically exposed to xenoestrogens for many generations. Two plausible explanations for the observed results could be given: a non-monotonic dose-response relationship or a mixture toxicity effect.
- Dispersive Liquid–Liquid Microextraction for the Simultaneous Determination of Parent and Nitrated Polycyclic Aromatic Hydrocarbons in Water SamplesPublication . Borges, Bárbara; Melo, Armindo; Ferreira, Isabel M.P.L.V.O.; Mansilha, CatarinaA new method for simultaneous extraction and quantification of 6 nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) and 16 parent polycyclic aromatic hydrocarbons (PAHs) in water matrices was optimized and validated. The extraction procedure was based on dispersive liquid-liquid microextraction technique, followed by gas chromatography-mass detection. The optimum conditions of extraction (volume of the extraction solvent, dispersive solvents and amount of salt) were selected using central composite design. The best results were found by using 200 μL of acetonitrile as dispersive solvent, 60 μL of chloroform as extraction solvent, and 10% (w/v) NaCl. Excellent linearity was observed in the range of 10–150 ng L−1 with correlation coefficients (r2) ranging between 0.9996 and 0.9999 for nitro-PAHs and in the range of 5–150 ng L−1 with r2 ranging from 0.9998 to 1.000 for PAHs. The limits of detection for the nitro-PAHs studied ranged from 0.82 to 3.37 ng L−1, whereas for PAHs ranged from 0.62 to 3.48 ng L−1. The intra- and inter-day precisions for nitro-PAHs were in the range of 0.45 to 19.54% and 0.43 to 19.62%, respectively, and for PAHs ranged between 0.45 to 17.42% and 0.38 to 18.97%, respectively. The proposed method was successfully applied in analyses of groundwater, sea, rain water and river water, being appropriate for routine analyses.
- Environmental impact of intensive horticulture practices on groundwater content of nitrates, sodium, potassium and pesticidesPublication . Pinto, Edgar; Melo, Armindo; Mansilha, Catarina; Ferreira, Isabel
- Impact of forest fires on PAH levels in groundwater from mountain areasPublication . Mansilha, Catarina; Marques, Jorge; Carvalho, Alexandra; Guimarães, PedroWildfires, both natural and manmade, are a major environmental hazard with significant short-term and long-term effects on human health and environment. Independently of fire type and intensity, the combustion process generates huge amounts of carbon dioxide and several groups of pollutants such as dioxins, dibenzofurans and polycyclic aromatic hydrocarbons (PAHs). Due to their potential adverse effects on humans and wildlife, PAHs are registered on European and American lists of priority pollutants that must be monitored in environment 1. Several PAHs compounds can increase the incidence of cancer, and are also referred to as endocrine disruptor compounds, with the most well-known marker being benzo[a]pyrene 2,3. Regarding water quality, PAHs were firstly considered priority hazardous substances (those presenting a significant risk to or via the aquatic environment) by the Decision nº2455/2001/EC of the European Parliament and of the Council, which becomes Annex X of the Water Framework Directive (2000/60/EC). This list was then replaced by Annex II of the Directive 2008/105/EC, known as the Priority Substances Directive, subsequently reviewed by the Commission in 2012 (COM(2011) 876 final. Until now, there are still substantial knowledge gaps about the water quality impacts of forest fires concerning PAHs contamination 3. The aim of this study was to analyse groundwater samples from two granitic mountain regions located in protected areas: Serra da Estrela (Central Portugal) and Serra do Gerês (North Portugal). The sampling networks were established in order to include springs from water table aquifers in areas affected by wildfires which took place in different years in order to determine contents of 16 priority PAHs. All the selected sampling points keep flowing throughout the year (in order to avoid temporary springs supplied by interflow) and are located upstream from roads (so that PAHs originated by road traffic are not present). The contribution of wildfires to the content of PAHs in water was demonstrated, as well as the effect of the influence of the time elapsed since the last fire. The PAHs naphthalene, fluorene, anthracene, dibenzo(a,h)antracene, benzo(ghi)perylene and indene(1,2,3-cd)pyrene appear to be the major ones produced. Naphtalene, anthracene and indene(1,2,3-cd)pyrene levels were remarkably high comparing to the control water sample and still remain in water several years after the last fire event.
- «
- 1 (current)
- 2
- 3
- »