Search results for " Mercury"

Gaseous Elemental Mercury (GEM) from mining areas and volcanic and geothermal systems in some Mediterranean areas: a preliminary study

2013

The pseudostationary mercury electrode

1998

Abstract A detailed study of the pseudostationary mercury electrode is presented, based on its use in LSV. Delay times ( t 1 ) as short as 20 ms can be employed; the drop area is still given by its classical expression, and minimization of the ohmic drop allows sweep rates of a few thousands of volts per second to be used. The conditions for pseudostationarity are given; the lower sweep rates utilizable are of the order of few tenths of volt per second. Reactant adsorption is considered, and zones where rehomogenization near the electrode surface is practically either 100 or 0% are defined in a plane log t 1 /log b O ( b O is the adsorption coefficient); the diffusional or surface character…

The relativity experiment of MORE: Global full-cycle simulation and results

2015

BepiColombo is a joint ESA/JAXA mission to Mercury with challenging objectives regarding geophysics, geodesy and fundamental physics. In particular, the Mercury Orbiter Radio science Experiment (MORE) intends, as one of its goals, to perform a test of General Relativity. This can be done by measuring and constraining the parametrized post-Newtonian (PPN) parameters to an accuracy significantly better than current one. In this work we perform a global numerical full-cycle simulation of the BepiColombo Radio Science Experiments (RSE) in a realistic scenario, focussing on the relativity experiment, solving simultaneously for all the parameters of interest for RSE in a global least squares fit …

Geothermal mercury output at Nisyros Volcano (Greece)

2019

Nisyros (Greece) is an active volcano in the eastern part of the South Aegean Active Volcanic Arc (SAAVA), hosting a high-enthalpy geothermal system. On June 2013, an extensive survey on Hg concentrations in different types of matrices (fumarolic fluids, atmosphere, soils and plants) was carried out at Lakki plain, an area affected by widespread soil degassing and fumarolic manifestations. To investigate the spatial distribution of mercury emission and its possible relationships with diffuse degassing of hydrothermal fluids, Hg concentrations in soils were related to their physicochemical parameters (e.g. temperature, soil-pH, hydrothermal gases and elemental C, N and S concentrations). Fur…

Renal and neurologic effects of cadmium, lead, mercury, and arsenic in children: evidence of early effects and multiple interactions at environmental…

2006

We read with great interest the article by de Burbure et al. (2006) on health effects in children who live near nonferrous smelters in France, the Czech Republic, and Poland. We were especially interested in the inverse relationship found between levels of urinary mercury and serum prolactin. We found a similar result in an Italian multicenter crosssectional survey with adult subjects (Alessio et al. 2002) using a different statistical approach based on regression analysis with mixed linear models. We found that serum prolactin decreased as a function of both urinary mercury and occupational exposure to inorganic mercury (Lucchini et al. 2003). In another study (Carta et al. 2003), our grou…

The sea–air exchange of mercury (Hg) in the marine boundary layer of the Augusta basin (southern Italy): Concentrations and evasion flux

2013

Abstract The first attempt to systematically investigate the atmospheric mercury (Hg) in the MBL of the Augusta basin (SE Sicily, Italy) has been undertaken. In the past the basin was the receptor for Hg from an intense industrial activity which contaminated the bottom sediments of the Bay, making this area a potential source of pollution for the surrounding Mediterranean. Three oceanographic cruises have been thus performed in the basin during the winter and summer 2011/2012, where we estimated averaged Hg atm concentrations of about 1.5 ± 0.4 (range 0.9–3.1) and 2.1 ± 0.98 (range 1.1–3.1) ng m −3 for the two seasons, respectively. These data are somewhat higher than the background Hg atm …

Bioindication of volcanic mercury (Hg) deposition around Mt. Etna (Sicily)

2012

Mt. Etna is a major natural source of Hg to the Mediterranean region. Total mercury concentrations, [Hg] tot, in Castanea sativa (sweet chestnut) leaves sampled 7-13km from Etna's vents (during six campaigns in 2005-2011) were determined using atomic absorption spectroscopy. [Hg] tot in C. sativa was greatest on Etna's SE flank reflecting Hg deposition from the typically overhead volcanic plume. [Hg] tot also showed Hg accumulation over the growing season, increasing with leaf age and recent eruptive activity. [Hg] tot in C. sativa was not controlled by [Hg] tot in soils, which instead was greatest on Etna's NW flank, and was correlated with the proportion of organic matter in the soil (% O…

Gas-Phase Photolysis of Hg(I) Radical Species: A New Atmospheric Mercury Reduction Process

2019

The efficient gas-phase photoreduction of Hg(II) has recently been shown to change mercury cycling significantly in the atmosphere and its deposition to the Earth's surface. However, the photolysis of key Hg(I) species within that cycle is currently not considered. Here we present ultraviolet-visible absorption spectra and cross-sections of HgCl, HgBr, HgI, and HgOH radicals, computed by high-level quantum-chemical methods, and show for the first time that gas-phase Hg(I) photoreduction can occur at time scales that eventually would influence the mercury chemistry in the atmosphere. These results provide new fundamental understanding of the photobehavior of Hg(I) radicals and show that the …

Polarographic and voltammetric methods for the determination of elements

1978

Measurements of the correlations between current, voltage and time, when microelectrodes are used, yield qualitative and quantitative information on the elemental composition of the solution investigated, if the method of measurement is properly chosen. Instrumental development today makes it possible, even at electrodes which make measurement difficult, such as the classical dropping mercury electrode, to obtain more reliable information on detection limits and number of elements detectable, by taking into account the functional interdependence of interference parameters and signal generation. Simultaneous determination of several components is possible, especially with non-linear a. c. po…

Active Moss biomonitoring of mercury in the mine-polluted area of Mt. Amiata (Central Italy)

2015

In the winter 2013, mercury concentrations in air from the mine-polluted area of Mt. Amiata (1738 m a.s.l.), in southern Tuscany (Central Italy), were measured by active moss biomonitoring. This area is part of the geologic anomaly of Hg in the Mediterranean basin, which contains about 65 % of the world’s cinnabar (HgS). Mt. Amiata covers some 400 km2 and is drained by several rivers. Esploitation activity at Abbadia S. Salvatore, in the SE sector of the mountain, sprang up during the 19th century as one of the largest mercury mining and smelting plants in Europe, after those of Almaden Spain. In this area, Sphagnum moss bags were exposed for about two months, from October to December 2013.…