Publications by authors named "I Diaz-Frances"

An extensive study on Po was conducted at Castillos Lagoon, a shallow brackish lagoon on the east coast of Uruguay, aiming to determine the activity concentrations of Po in various compartments and to derive the activity fluxes among them. The activity concentration of Po was determined in water, sediments, six different species of fishes, crabs, shrimps, phytoplankton, and zooplankton. Po was determined using alpha spectrometry, performing radiochemical separation and self-deposition on silver disc.

View Article and Find Full Text PDF

This paper presents the levels and distribution of Po in different compartments of a coastal lagoon on the east coast of Uruguay (South America). Activity concentrations of Po have been obtained in different matrices, such as water, superficial sediments, clams (Diplodon sp.), freshwaters snails (Pomacea sp.

View Article and Find Full Text PDF

The mining activities performed in the Iberian Pyrite Belt (south of Spain) have generated since long-time acid mining drainage (AMD) inputs to the Odiel River and its tributaries. These inputs are continuing nowadays, with origin mostly in the abandoned mines that cover the area, provoking a steady-state situation where the river waters present very low pH and very high concentrations of different heavy metals. In this work, the behavior of several natural radionuclides (Po, Th- and U-isotopes) in water and sediment samples collected in the Odiel River and its tributaries have been analyzed and their levels determined looking for assessing the radiological environmental impact of the AMD.

View Article and Find Full Text PDF

A radiological evaluation associated to the future mining of grey monazite nodules enriched in light rare-earths, from a modest superficial deposit located in the centre of Spain, has been performed at pre-operational level, and the main results are shown in this paper. Although the monazite nodules in the deposit are clearly enriched in radionuclides from the uranium and thorium series with activity concentrations higher than 1 Bq/g, the size of these nodules (in the 0.5 mm-2 mm grain size interval), its refractory behaviour that prevents the leaching or dissemination of natural radionuclides to waters or other ecosystem compartments and consequently the impact in the food chain, and its presence quite diluted in the deposit at concentrations of 2.

View Article and Find Full Text PDF
Article Synopsis
  • - Mining activities can increase metal mobility and availability in the environment by speeding up the dissolution of minerals and generating acid mine drainage (AMD), which enhances metal dissolution in mining areas.
  • - A study evaluated the behavior and transfer factors of uranium (U), thorium (Th), and polonium (Po) in plants (soybean, wheat, pine, eucalyptus) near a coal mine in southern Brazil, finding that Po accumulates the most in plant leaves, while pine and eucalyptus had the highest transfer factors for U.
  • - The research noted deviations from natural U isotopic ratios in the plants, suggesting industrial contamination, highlighting the need for safety assessments of soil and radionuclide accumulation in areas used for agriculture, especially in tropical
View Article and Find Full Text PDF