Cristina M. M. Almeida

Photodegradation kinetics and transformation products of ketoprofen, diclofenac and atenolol in pure water and treated wastewater

Pharmaceutical compounds such as ketoprofen, diclofenac and atenolol are frequently detected at relatively high concentrations in secondary effluents from wastewater treatment plants. Therefore, it is important to assess their transformation kinetics and intermediates in subsequent disinfection processes, such as direct ultraviolet (UV) irradiation. The photodegradation kinetics of these compounds using a medium pressure (MP) lamp was assessed in pure water, as well as in filtered and unfiltered treated wastewater. Ketoprofen had the highest time- and fluence-based rate constants in all experiments, whereas atenolol had the lowest values, which is consistent with the corresponding decadic molar absorption coefficient and quantum yield. The fluence-based rate constants of all compounds were evaluated in filtered and unfiltered wastewater matrices as well as in pure water. Furthermore, transformation products of ketoprofen, diclofenac and atenolol were identified and monitored throughout the irradiation experiments, and photodegradation pathways were proposed for each compound. This enabled the identification of persistent transformation products, which are potentially discharged from WWTP disinfection works employing UV photolysis.

Analysis of BTEX and other substituted benzenes in water using headspace SPME-GC-FID: method validation

The analysis of BTEX and other substituted benzenes in water samples using solid phase microextraction (SPME) and quantification by gas chromatography with flame ionization detection (GC-FID) was validated. The best analytical conditions were obtained using PDMS/DVB/CAR fibre using headspace extraction (HS-SPME) at 50 [degree]C for 20 min without stirring. The linear range for each compound by HS-SPME with GC/FID was defined. The detection limits for these compounds obtained with PDMS/DVB/CAR fibre and GC/FID were: benzene (15 ng L(-1)), toluene (160 ng L(-1)), monochlorobenzene (54 ng L(-1)), ethylbenzene (32 ng L(-1)), m-xylene (56 ng L(-1)), p-xylene (69 ng L(-1)), styrene (35 ng L(-1)), o-xylene (42 ng L(-1)), m-dichlorobenzene (180 ng L(-1)), p-dichlorobenzene (230 ng L(-1)), o-dichlorobenzene (250 ng L(-1)) and trichlorobenzene (260 ng L(-1)). This headspace SPME-GC-FID method was compared with a previously validated method of analysis using closed-loop-stripping analysis (CLSA). The headspace SPME-GC-FID method is suitable for monitoring the production and distribution of potable water and was used, in field trials, for the analysis of samples from main intakes of water (surface or underground) and from the water supply system of a large area (Lisbon and neighbouring municipalities).

Analysis of polynuclear aromatic hydrocarbons by SPME-GC-FID in environmental and tap waters

A procedure based on solid phase microextraction (SPME) and gas chromatography with flame ionization detection (GC-FID) was developed and validated in order to determine the sixteen US EPA PAH (polynuclear aromatic hydrocarbons) compounds in water samples. The best analytical conditions were obtained using PDMS 30 µm fibre by direct immersion at 60 oC, 30 min, 1500 rpm and 10% NaCl. The method showed good linearity (R2 > 0.99), repeatability ( 71%). The detection limits were between 0.06 and 0.50 µg L-1. Other studies were also carried out, such as stability studies, repeated analysis on the same sample, intermediate precision and the influence of chlorine concentration in the recovery of the PAHs. This method was applied to several matrices, including tap water and real environmental samples (surface and underground water and rainwater).

Teor de fluoretos em infusões de chá verde (Camellia sinensis)

The aim of this work was to study the influence of green tea consumption on fluoride ingestion. The extraction conditions of fluorides from green tea infusions were defined and nine brands of green tea available in Portugal were analyzed. The quantification of fluorides in the green tea was preceded by the implementation and validation of the potentiometric method (commercial fluoride selective electrode). The concentration of fluorides in the samples ranged from 0. 8 to 2. 0 mg L-1.

Análise de fármacos em águas por SPE-UPLC-ESI-MS/MS

A method was developed for the analysis of 31 pharmaceutical compounds in Lisbons drinking water system, using solid-phase extraction (SPE) and ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). The method was validated through estimation of the linearity range, method detection and quantification limits, matrix effects, precision and accuracy. The method detection and quantification limit ranges were 0.009-10 and 0.03-33 ng/L, respectively. Analytes were quantified in water samples collected from the EPAL (Empresa Portuguesa das Aguas Livres S.A.) supply system. Carbamazepine, atenolol, sulfadiazine, sulfamethazine, sulfapyridine, sulfamethoxazole, acetaminophen, caffeine and erythromycin were quantified in the analysed samples.

Chemical and biochemical characterization and in vivo safety evaluation of pharmaceuticals in drinking water.

The water constituents that are currently subject to legal control are only a small fraction of the vast number of chemical substances and microorganisms that may occur in both the environment and water resources. The main objective of the present study was to study the health impact resulting from exposure to a mixture of pharmaceuticals that have been detected in tap water at low doses. Analyses of atenolol, caffeine, erythromycin, carbamazepine, and their metabolites in blood, urine, feces, fat tissue, liver, and kidney after exposure to a mixture of these pharmaceuticals in treated drinking water were performed. The effects of this exposure were assessed in rats by measuring biochemical markers of organ injury or dysfunction. Simultaneously, the selected pharmaceuticals were also quantified in both physiological fluids and organ homogenates by liquid chromatography-tandem mass spectrometry (performed in multiple reaction monitoring mode and full scan mode). Following exposure of rats to a concentration of a pharmaceutical which was 10 times higher than the concentration known to be present in tap water, trace levels of some pharmaceuticals and their metabolites were detected in biological samples. This exposure did, however, not lead to significant organ injury or dysfunction. Thus, the authors report an experimental model that can be used to characterize the safety profile of pharmaceuticals in treated drinking water using a multiorgan toxicity approach. Environ Toxicol Chem 2016;35:2674-2682.

Fluoride content of soft drinks, nectars, juices, juice drinks, concentrates, teas and infusions marketed in Portugal

A potentiometric method using a fluoride combination ion-selective electrode was validated and used to analyse 183 samples, including soft drinks, juices, nectars, juice drinks, concentrates, teas and infusions marketed in Portugal. The fluoride levels were higher in extract-based soft drinks, juice drinks and juice, with fluoride values of 0.86 ± 0.35, 0.40 ± 0.24 and 0.37 ± 0.11 mg l−1, respectively. The lowest fluoride concentration was found in infusion samples (0.12 ± 0.01 mg l−1), followed by teas and carbonated soft drinks with fluoride concentrations of 0.16 ± 0.12 and 0.18 ± 0.07 mg l−1, respectively. Nectars, concentrates and juice-based drinks had similar fluoride concentrations of 0.33 ± 0.16, 0.29 ± 0.12 and 0.25 ± 0.14 mg l−1, respectively. The fluoride concentrations in all these samples would only contribute intakes below the acceptable daily intake (ADI = 0.05 mg kg−1 body weight day−1), indicating that, individually, these beverages cannot induce fluoride toxicity in the population group of children.

Optimization and validation of FTIR method with tetrachloroethylene for determination of oils and grease in water matrices

O desenvolvimento de metodologias para a determinacao de oleos e gordura (OG) apresenta inumeras dificuldades e desafios para laboratorios analiticos, principalmente na analise de agua potavel devido ao seu baixo valor parametrico. O metodo de FTIR apos extracao com tetracloroetileno foi desenvolvido para o monitoramento e controle de OG em varios tipos de agua, tais como aguas naturais (agua superficial, agua subterrânea e agua de banho), efluentes e agua potavel. O metodo foi validado apos aplicacao de testes estatisticos e calculo da estimativa de incertezas, e provou ser uma boa alternativa ao Freon 113. Os resultados referentes aos estudos de linearidade, recuperacao, precisao, limites de deteccao, limites de quantificacao e estimativa de incerteza sao apresentados e discutidos. O metodo validado foi aplicado as varias matrizes de agua e demonstrou ser adequado ao monitoramento de oleos e gordura nestas matrizes em concentracoes maiores que 0,01 mg L -1 . The development of methods for oils and grease (OG) determination presents several difficulties and challenges for analytical laboratories, mainly for drinking water analysis regarding its low parametric value. FTIR method with tetrachloroethylene was developed for OG monitoring and control in several water matrices, such as natural waters (surface water, groundwater and bathing water), wastewaters and drinking water. The method was validated through the application of statistical tests and calculus of the uncertainty of the analytical assay, and proved to be a good alternative to Freon 113. Results regarding the calibration, linearity, OG recovery, precision, limits of detection and quantification, and uncertainty estimation are presented and discussed. The validated method was applied for the analysis of water samples from all studied matrices and was found to be appropriate for monitoring oil and grease in these matrices at levels higher than 0.01 mg L -1

Presence of nitrates in baby foods marketed in Portugal

Abstract This study was carried out to determine the current levels of nitrates in baby foods marketed in Lisbon, Portugal to estimate the toxicological risk associated with their intake. The nitrate content was determined in bottled baby foods of four varieties: vegetable-based foods, meat-based foods, fish-based foods, and fruit-based foods. A total of 39 samples were analyzed over the period 2010–2011. Average and median levels of nitrate in baby foods were lower than the maximum limits established by European Union legislation (200 mg kg−1). Median nitrate values in baby foods were 61, 30, 39, and 15 mg kg−1 w/w for vegetable-based baby foods, meat-based baby foods, fish-based baby foods, and fruit-based baby foods, respectively. The estimated nitrate daily intake through bottled baby foods for infants indicate that individually, these foods are not able to induce nitrate toxicity in the children population.

Contaminantes emergentes - fármacos: monitorização, avaliação do risco ambiental e do risco para a saúde humana

The impact of pharmaceutical active compounds (PhACs) on aquatic ecosystems is still unclear and the data on biodegradation, toxicity and environmental fate are scarce. Consequently, the potential chronic adverse effects on human health are subject of concern. Therefore and in the context of a PhD thesis, an ultra performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) using solid phase extraction (SPE) as the sample’s preparation method for analysis of PhACs in water samples were optimized and validated. A monitoring program in 2013 analysed 34 PhACs in 243 water samples (surface water, groundwater and drinking water) sorting by 20 sampling points along EPAL’s water supply system. Only 16 were quantified in the analysed samples, with maximum concentrations ranging from 0.46 to 46 ng/L in the water sources and 0.09 e 46 ng/L in drinking water. The environmental risk assessment performed suggests that only one pharmaceutical, erythromycin, has a risk quotient (RQ) higher than 1, indicating a high risk for the environment. The results of the human health risk assessment indicate that the occurrence of adverse effects in the consumer ́s health are unlikely, as none of the pharmaceuticals presented RQ values higher than 1 or 0.1.