Risk analysis of technological hazards: Simulation of scenarios and application of a local vulnerability index.

The potential impact of a technological accident can be assessed by risk estimation. Taking this into account, the latent or potential condition can be warned and mitigated. In this work we propose a methodology to estimate risk of technological hazards, focused on two components. The first one is the processing of meteorological databases to define the most probably and conservative scenario of study, and the second one, is the application of a local social vulnerability index to classify the population. In this case of study, the risk was estimated for a hypothetical release of liquefied ammonia in a meat-packing industry in the city of La Plata, Argentina. The method consists in integrating the simulated toxic threat zone with ALOHA software, and the layer of sociodemographic classification of the affected population. The results show the areas associated with higher risks of exposure to ammonia, which are worth being addressed for the prevention of disasters in the region. Advantageously, this systemic approach is methodologically flexible as it provides the possibility of being applied in various scenarios based on the available information of both, the exposed population and its meteorology. Furthermore, this methodology optimizes the processing of the input data and its calculation.

Cu(II) acute toxicity to the rotifer Brachionus calyciflorus, as affected by fulvic acids of freshwater origin.

Natural fulvic acids (FA) from the Rio Santiago, an affluent of the Rio de la Plata estuary, were isolated by adsorption on XAD-2 at pH 2, and were then characterized by IR and fluorescence spectra, acidity and complexing capacity to Cu(II). The effect of the interaction between FA and Cu(II) on the acute toxicity of this heavy metal was assayed with the rotifer Brachionus calyciflorus in standardized in-vitro tests. A CuSO(4).5H(2)O concentration of 0.080 ppm produced 89.2% mortality in the absence of FA. At FA/Cu ratios >/= 1 no mortality was observed. Based on the values of the FA-Cu binding parameters and acute toxicity inhibition, it was possible to predict the effect of dissolved organic matter on the toxicity of copper in this surface freshwater body.