The Experts below are selected from a list of 225 Experts worldwide ranked by ideXlab platform

Julio A. Camargo - One of the best experts on this subject based on the ideXlab platform.

  • contribution of spanish american Silver Mines 1570 1820 to the present high mercury concentrations in the global environment a review
    Chemosphere, 2002
    Co-Authors: Julio A. Camargo
    Abstract:

    In this review I evaluate the contribution of Spanish-American Silver Mines during the period 1570-1820 (a Spanish colonial period of 250 years) to the present high mercury concentrations in the global environment. The evaluation is based upon the following bibliographic information: (1) total amount of mercury consumed in Spanish-American Silver Mines between 1570 and 1820; (2) percentage of the total amount of mercury consumed in Spanish-American Silver Mines that may have been emitted to the atmosphere; (3) global natural input of mercury to the atmosphere; (4) worldwide anthropogenic emissions of mercury to the atmosphere; (5) residence time of mercury in the atmosphere; and (6) capacity of mercury to be deposited in the sediments of aquatic systems. From all this information, and owing to the relatively long time that has passed since Spanish-American Silver Mines were operational, I conclude that most of the mercury lost during the refining of Silver via the patio amalgamation process is now sequestered into the sediments of aquatic systems, mainly in marine sediments. The high mercury concentrations now being reported in the global environment essentially are a consequence of the huge pollution caused by human activities during the past 20th century.

  • Contribution of Spanish–American Silver Mines (1570–1820) to the present high mercury concentrations in the global environment: a review
    Chemosphere, 2002
    Co-Authors: Julio A. Camargo
    Abstract:

    Abstract In this review I evaluate the contribution of Spanish–American Silver Mines during the period 1570–1820 (a Spanish colonial period of 250 years) to the present high mercury concentrations in the global environment. The evaluation is based upon the following bibliographic information: (1) total amount of mercury consumed in Spanish–American Silver Mines between 1570 and 1820; (2) percentage of the total amount of mercury consumed in Spanish–American Silver Mines that may have been emitted to the atmosphere; (3) global natural input of mercury to the atmosphere; (4) world-wide anthropogenic emissions of mercury to the atmosphere; (5) residence time of mercury in the atmosphere; and (6) capacity of mercury to be deposited in the sediments of aquatic systems. From all this information, and owing to the relatively long time that has passed since Spanish–American Silver Mines were operational, I conclude that most of the mercury lost during the refining of Silver via the patio amalgamation process is now sequestered into the sediments of aquatic systems, mainly in marine sediments. The high mercury concentrations now being reported in the global environment essentially are a consequence of the huge pollution caused by human activities during the past 20th century.

Hans Toni Ratte - One of the best experts on this subject based on the ideXlab platform.

  • bioaccumulation and toxicity of Silver compounds a review
    Environmental Toxicology and Chemistry, 1999
    Co-Authors: Hans Toni Ratte
    Abstract:

    A eview of the literature revealed that bioaccumulation of Silver in soil is rather low, even if the soil is amended with Silver-containing sewage sludge. Plants grown on tailings of Silver Mines were found to have Silver primarily in the root systems. In marine and freshwater systems, the highest reported bioconcentration factors (BCFs) were observed in algae (>105), probably because of adsorption of the dissolved Silver (<0.45 μm fraction) to the cell surface. In herbivorous organisms (e.g., zooplankton and bivalves), the BCF was lower by about two orders of magnitude. Low amounts of Silver were assimilated from food with no substantial biomagnification. In carnivores (e.g., fish), the BCF was also lower by one order of magnitude with no indication of biomagnification. Toxicity of Silver occurs mainly in the aqueous phase and depends on the concentration of active, free Ag+ ions. Accordingly, many processes and water characteristics reduce Silver toxicity by stopping the formation of free Ag+, binding Ag+, or preventing binding of Ag+ to the reactive surfaces of organisms. The solubility of a Silver compound, and the presence of complexing agents (e.g., thiosulfate or chloride), dissolved organic carbon, and competing ions are important. In soil, sewage sludge, and sediments, in which Silver sulfide predominates, the toxicity of Silver, even at high total concentrations, is very low. The highly soluble Silver thiosulfate complex has low toxicity, which can be attributed to the Silver complexed by thiosulfate. Silver nitrate is one of the most toxic Silver compounds. The toxic potential of Silver chloride complexes in seawater is and will be an important issue for investigation. Aquatic chronic tests, long-term tests, and tests including sensitive life stages show lower toxicity thresholds (˜1 μg Ag+/L). The organisms viewed as most sensitive to Silver are small aquatic invertebrates, particularly embryonic and larval stages.

  • Bioaccumulation and toxicity of Silver compounds: A review
    Environmental Toxicology and Chemistry, 1999
    Co-Authors: Hans Toni Ratte
    Abstract:

    A eview of the literature revealed that bioaccumulation of Silver in soil is rather low, even if the soil is amended with Silver-containing sewage sludge. Plants grown on tailings of Silver Mines were found to have Silver primarily in the root systems. In marine and freshwater systems, the highest reported bioconcentration factors (BCFs) were observed in algae (>105), probably because of adsorption of the dissolved Silver (

Jürgen Heckes - One of the best experts on this subject based on the ideXlab platform.

  • Remote Sensing Study of the Ancient Jabali Silver Mines (Yemen): From Past to Present
    Satellite Remote Sensing, 2011
    Co-Authors: Jean-paul Deroin, Florian Téreygeol, Jürgen Heckes
    Abstract:

    Archaeological research into the ancient Jabali Silver Mines in northern Yemen is a multidisciplinary project linking archaeologists, historians, and geologists, supported by remote satellite-based sensing. Mining companies are considering the development of the Jabali deposit for zinc ore. Some of the facilities, including a large open pit, will have a destructive impact on the old pits. Multispectral (Landsat TM, Terra ASTER, ALOS-AVNIR-2, etc.) and very high spatial resolution images such as QuickBird have been widely used for the geological setting and detail mapping of the different archaeological sites. The remote sensing data also provides a solid basis when it comes to detecting current operational sites.

  • evaluation of very high to medium resolution multispectral satellite imagery for geoarchaeology in arid regions case study from jabali yemen
    Journal of Archaeological Science, 2011
    Co-Authors: Jean-paul Deroin, Florian Téreygeol, Jürgen Heckes
    Abstract:

    Abstract Archaeological research of the ancient Jabali Silver Mines (7th to 14th centuries ad ) in northern Yemen is a multidisciplinary project covering scientific disciplines traditionally related to archaeology, a geological approach and new technologies such as very high resolution remote sensing. Mining companies envisage the development of the Jabali deposit for zinc ore. Some of the planned facilities, particularly a large open pit, will have a destructive impact on the old pits and processing heaps, already damaged by recent works. In the present study, remote sensing is used for a detailed survey of the impact of preliminary mining works from the early 1980’s with the aim to establish archaeological remains and to prioritize areas for future ground surveys, as well as for geological mapping. Results indicate that mapping using remote sensing in the visible to short wave infrared range has a great potential for the identification of gossans (iron caps) possibly related to archaeological remains. The phases of work in Jabali are clearly put into light by the study of a time series of Landsat data. Very high resolution QuickBird imagery appears particularly relevant for mapping most of the archaeological remnants, iron caps, as well as the 3D visualization of the mining site when drapped over a detailed digital elevation model.

F.s. Nordrum - One of the best experts on this subject based on the ideXlab platform.

B.i. Berg - One of the best experts on this subject based on the ideXlab platform.