Search results for " metal"

Mercury gas emissions from La Soufrière Volcano, Guadeloupe Island (Lesser Antilles)

2009

Abstract Quantifying mercury (Hg) emissions from active volcanoes is of particular interest for better constraining the global cycle and environmental impact of this highly toxic element. Here we report on the abundance of total gaseous (TGM = Hg 0 (g)  + Hg II (g) ) and particulate (Hg (p) ) mercury in the summit gas emissions of La Soufriere andesitic volcano (Guadeloupe island, Lesser Antilles), where enhanced degassing of mixed hydrothermal-magmatic volatiles has been occurring since 1992 from the Southern summit crater. We demonstrate that Hg in volcanic plume occurs predominantly as gaseous mercury, with a mean TGM/Hg (p) mass ratio of ~ 63. Combining the mean TGM/H 2 S mass ratio of …

Application and evaluation of biomagnetic and biochemical monitoring of the dispersion and deposition of volcanically-derived particles at Mt. Etna, …

2010

article i nfo Article history: Received 6 August 2009 Accepted 4 January 2010 Available online xxxx Biomagnetic monitoring, using tree leaves as passive surfaces for particle collection, has been shown to be a promising technique for assessing the dispersion and deposition of particles in the context of anthropogenic pollution. By comparing leaves' magnetic properties with trace metal levels measured in the leaves, we here assess the utility of the biomagnetic technique as a sensitive, fast and inexpensive method for assessment of volcanic plume deposition. Samples of sweet chestnut leaves (Castanea sativa) were collected from the area surrounding Mt. Etna volcano in Sicily during the 2008 …

Trace metal modeling of groundwater–gas–rock interactions in a volcanic aquifer: Mount Vesuvius, Southern Italy

2005

We report a detailed study of trace metals in groundwaters from the Somma-Vesuvius volcanic complex and present a model of the chemical processes that control the fate of these components during gas–water–rock interactions. Trace metal concentrations in Vesuvian groundwaters range from 0.01 to 0.1 Ag/l for ultra-trace elements (Sb, Cs, Co, Cd, and Pb) up to 0.1–10 mg/l for minor elements (Fe and Sr), leading to water–rock ratios from ~0.5 to 10 � 9 when normalized to trace element concentrations in the host rocks. Our results indicate non-isochemical dissolution of local volcanic rocks by groundwaters, during which mobile trace elements (As, Se, Mo, V, Li) are enriched and elements such as …

Degassing of trace volatile metals during the 2001 eruption of Etna

2003

This paper provides new data on sulfur, halogens, and minor and trace metal contents in airborne particulate matter from the Mt. Etna volcanic plume. Aerosol samples were collected by conventional filtration techniques before and during the summer 2001 eruption, in order to investigate relations between plume chemistry and volcano dynamics. Data analysis reveals that abundances of trace metals in the plume result from mixing of erosive and volatile components. The former is responsible for the contents of rare earth elements (REE), Ca, Ba, Sr, Ti, Sc, Y, Hf and Th; the latter contributes significantly to the abundance of Cs, Rb, Na and K, probably transported in the plume as metal halides, …

Kompleksy metali przejściowych z zasadami Lewisa jako prekursory katalizatorów polimeryzacji olefin. Cz. I. Postęp w komputerowym modelowaniu procesu…

2001

A review with 35 references covering molecular modeling in coordination polymerization over homogeneous and heterogeneous Ziegler-Natta catalysts. The study includes supports, cocatalysts, Lewis bases and solvents. Recent progress in elucidating the mechanisrn of elementary polymerization steps is presented against the background of rapidly deveIoping computational methods and available computational power. Theoretical studies on polymerization mcchanisms and structure of active centers are described (egns. 1-4). Authors own calculations are used to compare [MtC14(THF)2] complex-based (Mt = Ti, Hf or Zr) heterogeneous catalysts. The geometrical characteristics of precursors is presented (Ta…

Materiali tradizionali per una nuova arte orafa mediterranea

2010

Do Volcanic Eruptions Solve Global Atmospheric Mercury Pollution?

2011

Besides human activities, volcanoes also introduce significant quantities of potentially harmful chemical compounds into the environment, mainly in the forms of gases and particles. High-temperature emissions from persistently degassing volcanoes are a known source of trace metal emissions to the atmosphere which may have important environmental consequences. Among these metals, mercury (Hg) is of particular interest since it is a toxic volatile metal found at elevated concentrations in remote regions of the world. Many natural Hg pathways include a recycled component of anthropogenic material. The anthropogenic contribution to the global atmospheric Hg budget is now well constrained, with …

Use of algae in active biomonitoring of Surface waters

2014

Przeprowadzono badania biomonitoringowe trzech zbiorników retencyjnych położonych na terenie województwa opolskiego (południowa Polska): Zbiornika Turawa, Zbiornika Nysa i Zbiornika Otmuchów. W glonach słodkowodnych Spirogyra sp. i morskich Palmaria palmata (Linnaeus) Weber & Mohr, eksponowanych w badanych wodach, oznaczono metodą absorpcyjnej spektrometrii atomowej (AAS) przyrosty stężeń: Mn, Fe, Cu, Zn, Cd i Pb. W wodach oznaczano także pH, konduktywność oraz stężenie Mn i Fe. Stężenia Cu, Zn, Cd i Pb w badanych wodach były mniejsze od granicy oznaczalności metody. Badania prowadzono od czerwca do lipca 2014 r. Wskazano na różnice w przyrostach stężeń metali ciężkich w próbkach glonów eks…

The oocyte derived growth factors, GDF9 and GDF9B, and their biological activities in 'in vitro' cell models

2007

Biokumulacja pierwiastków w grzybach wielkoowocnikowych - przegląd wybranej literatury

2017

Celem pracy było dokonanie analizy bibliometrycznej wybranych publikacji dotyczących akumulacji pierwiastków w grzybach wielkoowocnikowych (ektomikoryzowych i saprofitycznych) występujących na terenie Europy. Analizie poddano wybrane publikacje z lat 2001-2016 dostępne poprzez serwisy, np.: Springer, Science Direct i Web of Science. Przeanalizowano m.in. akumulowane mikro- i makropierwiastki, miejsca prowadzenia badań oraz typ badań (m.in. badania in situ, badania laboratoryjne). W wyniku przeprowadzonych badań literaturowych stwierdzono, że temat translokacji pierwiastków do grzybów wielkoowocnikowych jest nadal aktualny i cieszy się dużym zainteresowaniem naukowców z wielu krajów europejs…