62 research outputs found

    Long-term TNT and DNT contamination: 1-D modeling of natural attenuation in the vadose zone: case study, Portugal

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    The vadose zone of a trinitrotoluene (TNT) and dinitrotoluene (DNT) contaminated site was investigated to assess the mobility of those explosives under natural conditions. Located in the left margin of the River Tejo Basin, Portugal, the site is located on unconsolidated sediments. Wastewaters associated with the 50-year explosives production were disposed in excavated ponds, from where water would infiltrate and pollute the unsaturated and saturated parts of the local aquifers. Two boreholes were drilled to 9 m depth in such a former waste pond to investigate the contaminant's fate in the vadose zone. Sediment samples were taken every 1-2 m for analysis of the polynitroaromatics (p-NACs) and organic volatile compounds, pH, organic carbon content, cation exchange capacity and grain size analysis. The main contaminant was TNT representing >70 % of the total p-NACs concentration that peaked approximately 7 mg/kg in one borehole, even if the median in both boreholes was of similar to 1 mg/kg. DNT was 4-30 % of the total p-NACs and nitrotoluene (NT), up to 5 %. No other (volatile) organic compound was detected. The predominance of TNT as the main contaminant implies that any natural mass reduction has been inefficient to clean the site. Several 1-D model simulations of p-NACs cleaning of the vadose zone under natural conditions indicated that the most probable scenario of combined advection and partitioning will only remove TNT after 10's of years, whereas DNT and NT will hardly be removed. Such low concentrations and long times for the p-NACs removal, suggest that by now those compounds have been washed-out to a level below standard limits

    HIV Among Indigenous peoples: A Review of the Literature on HIV-Related Behaviour Since the Beginning of the Epidemic

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    Резонанс. 2009. № 38

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    The political, economic and environmental policies of a hegemonic, oligarchic, political-economic international caste are the origin and cause of the ecological and political dystopia that we are living in. An utilitarian, resourcist, anthropocentric perspective guides classical economics and sustainable development models, allowing the enrichment of a tiny part of the world's population, while not impeding but, on the contrary, directly inducing economic losses and environmental destruction for the many. To preserve the integrity of natural systems we must abandon the resourcist anthropocentric ethical fiction that is the current moral foundation underlying our relationship with nature and instead promote the realization of a new developmental landmark for democratic institutions: direct democracy, i.e. democracy truly governed by the people for the people, and ultimately for nature as well
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