Browsing by Author "Bustamante, Elena"

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    Importance of water quality on plant abundance and diversity in high-alpine meadows of the Yerba Loca Natural Sanctuary at the Andes of north-central Chile
    (2008) Ginocchio, Rosanna; Hepp, Josefina; Bustamante, Elena; Silva, Yasna; Maria De La Fuente, Luz; Francois Casale, Jean; Paul De La Harpe, Jean; Urrestarazu, Paola; Anic, Vinka; Montenegro, Gloria
    Porphyry Cu-Mo deposits have influenced Surface water quality in high-Andes of north-central Chile since the Miocene. Water anomalies may reduce species abundance and diversity in alpine meadows as acidic and metal-rich waters are highly toxic to plants The study assessed the importance of surface water quality on plant abundance and diversity in high-alpine meadows at the Yerba Loca Natural Santuary (YLNS), central Chile (33 degrees 15' S, 70 degrees 18' W). Hydrochemical and plant prospecting were carried out on Piedra Carvajal, Chorrillos del Plomo and Lit Lata meadows the growing seasons of 2006 and 2007. Direct gradient analysis was performed through canonical correspondence analysis (CCA) to look for relationships among water chemistry and plant factors. High variability in water chemistry was found inside and among meadows, particularly for pH, sulphate, electric conductivity, hardness, and total dissolved Cu, Zn, Cd, Ph and Fe. Data oil species abundance and water chemical factors suggests that pH and total dissolved Cu are very important factor determining changes in plant abundance and diversity in study meadows. For instance, Festuca purpurascens, Colobanthus quitensis, and Arenaria rivularis are abundant in habitats with Cu-rich waters while Festuca magellanica, Patosita clandestina, Plantago barbata, Werneria pygmea, and Erigeron andicola are abundant in habitats with dilute waters.
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    SOIL ACIDIFICATION AS A CONFOUNDING FACTOR ON METAL PHYTOTOXICITY IN SOILS SPIKED WITH COPPER-RICH MINE WASTES
    (WILEY, 2009) Ginocchio, Rosanna; Maria de la Fuente, Luz; Sanchez, Pablo; Bustamante, Elena; Silva, Yasna; Urrestarazu, Paola; Rodriguez, Patricio H.
    Pollution of soil with mine wastes results in both Cu enrichment and soil acidification. This confounding effect may be very important in terms of phytotoxicity, because pH is a key parameter influencing Cu solubility in soil solution. Laboratory toxicity tests were used to assess the effect of acidification by acidic mine wastes on Cu solubility and on root elongation of barley (Hordeum vulgare L.). Three contrasting substrates (two soils and a commercial sand) and two acidic, Cu-rich mine wastes (oxidized tailings [OxT] and smelter dust [SmD]) were selected as experimental materials. Substrates were spiked with a fixed amount of either SmD or OxT, and the pH of experimental mixtures was then modified in the range of 4.0 to 6.0 and 7.0 using PIPES (piperazine-1,4-bis(2-ethanesulfonic acid)), MES (2-(N-morpholino) ethanesulfonic acid), and MOPS (3-(N-Morpholino)-propanesulfonic acid) buffers. Chemical (pore-water Cu and pH) and toxicological (root length of barley plants) parameters were determined for experimental mixtures. Addition of SmD and OxT to substrates resulted in acidification (0.11-1.16 pH units) and high levels of soluble Cu and Zn. Neutralization of experimental mixtures with MES (pH 6.0) and MOPS (pH 7.0) buffers resulted in a marked decrease in soluble Cu and Zn, but the intensity of the effect was substrate-dependent. Adjustment of soil pH above the range normally considered to be toxic to plants (pH in water extract, > 5.5) significantly reduced metal toxicity in barley, but phytotoxicity was not completely eliminated. The present results stress the importance of considering confounding effects on derivation of toxicity thresholds to plants when using laboratory phytotoxicity tests.