Time filter

Source Type

Pocas A.,National Laboratory for Civil Engineering | Pocas A.,Technical University of Delft | Miranda A.,Empresa Portuguesa de Aguas Livres SA | Paiva J.,Empresa Portuguesa de Aguas Livres SA | And 3 more authors.
Water Science and Technology: Water Supply

Loose deposits (LD) develop and accumulate in drinking water distribution systems' (DWDS) pipes and often lead to discolouration incidents, which are a major reason for customers' complaints. In addition, LD may accumulate contaminants, while discolouration may be accompanied by degradation of the water's microbiological quality. Along with iron oxides, organic compounds are well established as predominant constituents of LD. Even so, the composition and role of the latter remain unknown. Since microbial extracellular polymeric substances (EPS) are components of ironrich flocs from many freshwater environments, the presence of EPS in LD was investigated. This was confirmed by the systematic occurrence of polysaccharides and proteins in LD samples. In addition, microscopic observations and measurements of LD water contents showed that, like their freshwater counterparts, LD have a hydrogel floc nature and fractal morphology. By providing insights on LD origin and behaviour, these findings may be important for the understanding of DWDS water discolouration phenomena.© IWA Publishing 2013 Water Science and Technology: Water Supply. Source

Carvalho A.R.M.,University of Lisbon | Cardoso V.V.,Empresa Portuguesa de Aguas Livres SA | Rodrigues A.,Empresa Portuguesa de Aguas Livres SA | Ferreira E.,Empresa Portuguesa de Aguas Livres SA | And 2 more authors.
Environmental Monitoring and Assessment

This paper presents the study of the occurrence of 10 endocrine-disrupting compounds (EDCs) in 60 water samples using a method for simultaneous quantification and confirmation of the presence of these emerging compounds, using ultra-performance liquid chromatography with electrospray ionization and tandem mass spectrometry (UPLC-ESI-MS/MS). All samples were previously extracted by solid-phase extraction (SPE). Several natural and synthetic hormones (17-β-estradiol, ethinylestradiol, estriol, estrone, progesterone, mestranol, and diethylstilbestrol) and some industrial products (4-n-nonylphenol, 4-tert-octylphenol, and bisphenol A) were chosen for this survey. The analytical limits were calculated for each compound and were used in the identification and quantification of these target compounds in EPAL’s water supply system. In this study, several samples were taken from the main intakes of water (surface and groundwater) used for production of water for human consumption and from different sampling points of the drinking water distribution system (piping, nets, and reservoirs). Some target compounds, such as estriol, 4-tert-octylphenol, mestranol, and nonylphenol, were found in trace amounts in several water samples. However, the studied endocrine-disrupting appeared in very low concentrations when compared with the assessed analytical limits. © 2015, Springer International Publishing Switzerland. Source

Discover hidden collaborations