Browsing by Author "Costa, Sílvia"
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- Bacteroides spp. and traditional fecal indicator bacteria in water quality assessment – An integrated approach for hydric resources management in urban centersPublication . Teixeira, Pedro; Dias, Deodália; Costa, Sílvia; Brown, Bárbara; Silva, Susana; Valério, ElisabeteAs part of a sustainable water resources management, the Lisbon municipality identified groundwater and treated wastewater use increase as two opportunities for better and sustainable water use, with natural safeguard for public health as a priority. In this context, the aim of our research was to assess the suitability of the human-associated marker gene Bacteroides HF183 and the cattle feces-associated CowM2, in routine water quality monitoring as indicators for water use and reuse, providing a tool to more accurately assess public health risks. To this intent, Real-Time quantitative PCR was used for detection of human-associated marker gene Bacteroides HF183 and the bovine-associated CowM2, in a total of 67 samples - groundwater and wastewater at three different treatment stages of a Waste Water Treatment Plant, in Lisbon. HF183 marker gene was detected in treated and untreated wastewater samples, with significant concentration reductions from untreated (6,07 E+07 copies/mL) to secondary treated effluent (1,86 E+05 copies/mL) and a further decrease in tertiary treatment (5,74 E+04 copies/mL). In groundwater samples, this marker was also detected in concentrations ranging from 2,63 E+02 copies/mL to 2,24 E+03 copies/mL. CowM2 marker gene on the other hand was only detected in wastewater samples, with concentrations ranging from 2,47 E+02 copies/mL to 1,17 E+04 copies/mL. Our research indicates that the use of Bacteroides spp. in association with traditional fecal indicator bacteria (FIB) is advantageous for water managing entities in urban settings, such as Lisbon, were drainage system failures may occur. An integrated approach thus provides crucial and more adequate information towards mitigation and correction measures when fecal contamination is detected in environmental waters.
- Microbiological and chemical quality of ice used to preserve fish in Lisbon marketplacesPublication . Teixeira, Pedro; Brandão, João; Silva, Susana; Babič, Monika Novak; Gunde-Cimerman, Nina; Pires, Joana; Costa, Sílvia; Valério, ElisabeteIce is widely used to preserve fish on markets, playing a major role in the food industry. If manufactured, stored or distributed in inadequate sanitary conditions, it can represent a considerable health risk for both consumers and professionals. The present study characterizes ice used in marketplaces, on microbiological and chemical parameters. The aim was to assess potential risks on occupational exposure and consumer safety and therewith plan orientation guidelines. Sampling took place in 18 marketplaces in Lisbon, with ice samples collected at three different stages— production (n = 29), storage (n = 30), and product-contact (n = 29). No significant contamination was found in production and storage stages, demonstrating that ice production and storage procedures are adequate regarding sanitary conditions. With exception for Salmonella, significantly higher concentrations of microbial parameters were identified in product-contact stages, specifically Total Coliforms (548 MPN/100 mL), Escherichia coli (1 MPN/100 mL), Enterococci (29 MPN/100 mL), Staphylococcus aureus (271 CFU/100 mL), HPC at 5 , 22 , and 37 (>301 CFU/mL). Our study also shows that the majority of samples from ice production and storage comply with national regulations regarding drinking water quality. Yet, occupational health and consumer risks may still exist at the final product-contact stage, as significant contamination was detected.. Practical applications The present study can be used as a model for ice quality monitoring in fish preservation, serving as a tool for quality control and fast contamination detection during the several process stages. This monitoring model is an important contribution for assuring the safety of the preserved products, as well as, occupational health improvement and consumer risk protection.
- Non-potable use of Lisbon underground water: microbiological and hydrochemical data from a 4-year case studyPublication . Teixeira, Pedro; Almeida, Luís; Brandão, João; Costa, Sílvia; Pereira, Susana; Valério, ElisabeteMitigation of global warming scenarios by the United Nations Economic Commission for Europe (UNECE) water convention requires better water use policies by all management parties. One of Lisbon's municipal contributions to target a sustainable urban water cycle has been to assess the microbial and hydrochemical quality of groundwater. The aim is to clarify the possible existence of contaminations and respective sources, seasonality, and to assess non-drinking alternative uses of those waters. To this respect, five water sources over a 4-year period were monitored for physical, chemical, and microbial parameters (temperature, pH, NO2-, NO3-, NO4-, oxidability, conductivity, total hardness, Escherichia coli, total coliforms, enterococci, and heterotrophic plate count at 22 °C and 37 °C). The results show mean values of physical and chemical parameters within the WHO and national drinking water guidelines and regulations. However, microbial parameters exceed these limits, showing no seasonality. Microbial contamination may not necessarily imply the uselessness of groundwater for uses other than for drinking. For routine water quality assessment, a selection of a more adequate group of microbiological indicators is necessary, in order to evaluate potential public health risks, regarding the use of the identified water sources for non-potable purposes like irrigation or street cleaning. This approach is being promoted by the UNECE's protocol for water and health, article 6, 2 (i); in accordance with the scope of the UN's sustainable goals.
- Quantitative PCR Detection of Enteric Viruses in Wastewater and Environmental Water Sources by the Lisbon Municipality: a Case StudyPublication . Teixeira, Pedro; Costa, Sílvia; Brown, Bárbara; Silva, Susana; Rodrigues, Raquel; Valério, ElisabeteCurrent regulations and legislation require critical revision to determine safety for alternative water sources and water reuse as part of the solution to global water crisis. In order to fulfill those demands, Lisbon municipality decided to start water reuse as part of a sustainable hydric resources management, and there was a need to confirm safety and safeguard for public health for its use in this context. For this purpose, a study was designed that included a total of 88 samples collected from drinking, superficial, underground water, and wastewater at three different treatment stages. Quantitative Polimerase Chain Reaction (PCR) detection (qPCR) of enteric viruses Norovirus (NoV) genogroups I (GI) and II (GII) and Hepatitis A (HepA) was performed, and also FIB (E. coli, enterococci and fecal coliforms) concentrations were assessed. HepA virus was only detected in one untreated influent sample, whereas NoV GI/ NoV GI were detected in untreated wastewater (100/100%), secondary treated effluent (47/73%), and tertiary treated effluent (33/20%). Our study proposes that NoV GI and GII should be further studied to provide the support that they may be suitable indicators for water quality monitoring targeting wastewater treatment efficiency, regardless of the level of treatment.