1,721,214 research outputs found
Investigations of polyoxometalates in aqueous solutions. I. The formation of Al13(OH)327+ cation
No full textInvestigations of polyoxometalates in aqueous solutions. I. The formation of Al13(OH)327+ cation
No full textCopper Release in Drinking Water Due to Internal Corrosion of Distribution Pipes
No full textThe present paper deals with water quality modification during its stagnation in copper distribution pipes caused by electrochemical corrosion processes. Copper is chosen as plumbing material because of its wide use in drinking water distribution systems all around the world, and because of its recognized toxicity at high dosages. Several experiments are developed, varying water composition and stagnation length, to ascertain the dependence of copper release on both parameters. The effect of different concentrations of bicarbonates, sulphates and phosphates on metal release is studied, assuming stagnation periods ranging from 15 to 90 minutes. The corrosion potential of the metal surface during stagnation episodes is also monitored to verify the existence of a direct correlation between this potential at the end of each stagnation episode, and the corresponding total dissolved copper concentration in the stagnating water. The correlation allows to quantify copper release in drinking water, measuring the corrosion potential, drastically reducing, in this way, the cost of water quality monitoring
Caratterizzazione di malte di interesse archeologico: il caso studio del Rione Terra di Pozzuoli
No full text
The mineral springs of the Scrajo spa (Sorrento peninsula, Italy): a case of “natural” seawater intrusion
No full textThis paper deals with the mineral springs feeding the Scrajo spa in the Sorrento peninsula southeast of Naples, approximately six km from Castellamare di Stabia, another spa location. The Scrajo mineral water is sulfureous, salt-bromine-iodic and CO2 - rich. The two hydromineral areas fall within the groundwater basin of Mt. Faito formed chiefly by limestones. Due to the high permeability of the limestones there is considerable rainwater infiltration which recharges a basal fresh groundwater resting on denser seawater. This groundwater body feeds the mineral springs of the Scrajo spa, the springs of Castellammare di Stabia and some submarine springs.
All the data gathered for the Scrajo springs led to propose the following mineralisation scheme:
• the basal fresh groundwater of Mt. Faito (on underlying seawater) receives endogenous contributions of CO2 and H2S which cause a “natural” seawater intrusion within the fresh groundwater;
• the upwelling of gases would appear to occur via the major faults which bound Sorrento peninsula to the NW;
• during the year the chemistry of the springs changes according to the different degree of seawater intrusion: the minimum occurs in June and the maximum in November.
The close interaction between the sea and the Scrajo’s mineral waters (but also those of Castellammare di Stabia) highlights their particular vulnerability not only to over-extraction of groundwater but also to climate change. Finally, a hypothesis is presented explain the connection between the mineral waters rich in CO2 and H2S and the concentration of karst phenomena observed in the Scrajo area
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