1,721,048 research outputs found
Genesi e caratteri sedimentologici dei Travertini. I depositi di Travertino di Rapolano Terme
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Antimony and arsenic contents in fresh waters and stream sediments of the Monti Romani area (Southern Tuscany, Italy)
No full textA geochemical study of the distribution of antimony and arsenic in stream waters and sediments was carried out in the Monti Romani region (southern Tuscany, Italy) to assess the environmental impact of past mining activities. Significant and widespread Sb-(As) anomalies were detected near the main mining centers of the Monti Romani region. The Tafone and Macchia Casella-Poffio Fuoco mining areas have the highest enrichment levels of Sb and As in stream waters and sediments. In these zones, pollution can be ascribed to drainage and erosion of heavy element-contamined mine dumps. In the upper Chiarone stream (Mt. Capita zone), the anomalous values of antiomny in fresh waters are likely related to the natural circulation of meteoric waters through silicized and stibnite-mineralized carbonitic rocks
Environmental levels of antimony, arsenic and mercury in the Tafone mining area (Southern Tuscany, Italy)
No full textA geochemical survey on mine wastes, fresh waters and biota, carried out in the Monti Romani zone, reveals heavy Sb-(As-Hg) pollution in an area between the Tafone and Chiarone fluvial basins. In the Tafone stream there is a steep increase of the antimony content in water downstream of mine wastes as far as the mouth, with peak levels of the dissolved element. The waters of Tafone Lake also exhibit heavy antimony pollution and ichthyofauna have high levels of both Sb and Hg in muscle tissue. Wild and cultivated species of plants, collected in the neighborhood of mining areas, often present anomalous contents of these heavy elements. The environmental damage turns out to be closely linked to the wastes of mining and smelting activities and can be attributed largely to the cessation of mining works without any appropriate reclamation program
Chemical and biological methods to evaluate the availability of heavy metals in soils of the Siena urban area (Italy)
Full text linkA biogeochemistry field study was conducted in the Siena urban area (Italy) with the main objective of establishing the relationship between available amounts of heavy metals in soil assessed by a chemical method (soil fractionation) and bioavailability assessed by a biological method (bioaccumulation in earthworm tissues). The total content of traffic-related (Cd, Cu, Pb, Sb, Zn) and geogenic (Co, Cr, Ni, U) heavy metals in uncontaminated and contaminated soils and their concentrations in soil fractions and earthworms were used for this purpose. The bioavailability of heavy metals assessed by earthworms did not always match the availability defined by soil fractionation. Earthworms were a good indicator to assess the bioavailability of Pb and Sb in soil, while due to physiological mechanisms of regulation and excretion, Cd, Cu and Zn tissue levels in these invertebrates gave misleading estimates of their bioavailable pool. No relationship was identified between chemical and biological availability for the geogenic heavy metals, characterized by a narrow range of total contents in soil. The study highlighted that chemical and biological methods should be combined to provide more complete information about heavy element bioavailability in soils
Potentially toxic element contamination in soil and accumulation in maize plants in a smelter area in Kosovo
Full text linkA biogeochemical field study was carried out in the industrial area of Kosovska Mitrovica in northern Kosovo, where agricultural soils were contaminated by potentially toxic elements due to smelting activity. Total and bioavailable contents of As, Cd, Co, Cu, Pb, Sb, U and Zn in soil and their concentrations in maize roots and grains were determined. Soil contamination by As, Cd, Cu, Pb, Sb and Zn was variable from slightly to highly contaminated soils and influenced both the bioavailable fraction and accumulation of these potentially toxic elements in maize tissues. The comparison between potentially toxic element concentrations in roots and grains indicated that maize is able to limit the transfer of non-essential elements to edible parts. The plant-to-soil bioconcentration indices suggested that the transfer of potentially toxic elements from soil to plant was predicted better by bioavailable concentrations than by the total contents. These indices further identified some competitions and interactions among these elements in root uptake and root-to-grain translocation
Il Parco Nazionale Tecnologico e Archeologico delle Colline Metallifere Grossetane: un parco multitematico tra natura, geologia, geotermia, miniere ed archeologia mineraria ed industriale
No full textMercury content of the rocks of Tuscany. A geochemical contribution to geology of Hg-ores
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