Browsing by Author "Neaman, Alexander"

Now showing 1 - 7 of 7
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    Assessment of revegetation of an acidic metal(loid)-polluted soils six years after the incorporation of lime with and without compost
    (2018) Pardo, Javier; Mondaca, Pedro; Celis-Diez, Juan Luis; Ginocchio Cea, Rosanna; Navarro-Villarroel, Claudia; Neaman, Alexander
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    Comparison of exposure to trace elements through vegetable consumption between a mining area and an agricultural area in central Chile
    (2018) Aguilar, Marcelo; Mondaca, Pedro; Ginocchio Cea, Rosanna; Vidal, Kooichi; Sauve, Sebastien; Neaman, Alexander
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    Copper bioavailability and phytotoxicity in Chilean agricultural soils. Implications for sustainable fruit production
    (2024) Ginocchio Cea, Rosanna; Aponte, Humberto; Neaman, Alexander; Fuente Karlezi, Luz María de la; Schoffer, J. Tomas
    Central Chile's lowland valleys constitute a major fruit-producing region, but they face soil copper (Cu) contamination originating from Cu mining in the nearby Andes Mountains as well as the historical and ongoing use of Cu- based pesticides. This study investigated the potential toxicity of Cu to plants (phytotoxicity) in a representative fruit-growing valley. To assess this risk, soil samples were collected from 12 agricultural sites with documented Cu contamination and one uncontaminated site to serve as a baseline. A short-term bioassay was conducted using perennial ryegrass ( Lolium perenne) to evaluate the effects of Cu on plant growth. The results demonstrated that elevated Cu levels significantly reduced both the shoot length and dry mass of the ryegrass plants. However, other soil properties, such as the presence of soluble zinc, organic matter, available nitrogen, and clay content, could mitigate these negative effects. Interestingly, the estimated concentration of Cu causing a 50% reduction in plant growth (EC50) was greater than the values reported in previous studies. This may be because Cu binds to soil organic matter (SOM), which reduces its bioavailability and immediate toxicity to plants. While this binding to SOM can initially reduce the negative effects of Cu, the eventual breakdown of SOM over time may release Cu back into the soil, posing long-term risks to both crops and the wider soil ecosystem. To fully understand these potential long-term impacts, further research is needed and should include studies with other soil organisms, such as earthworms and microorganisms, to gain a more comprehensive understanding of the ecological consequences of Cu contamination in these vital agricultural systems.
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    Evaluation of connected clonal growth of Solidago chilensis as an avoidance mechanism in copper-polluted soils
    (2019) Lillo, Felipe; Ginocchio, Rosanna; Ulriksen, Christopher; Dovletyarova, Elvira A.; Neaman, Alexander
    Plant resistance to metals can be achieved by two strategies, tolerance and avoidance. Although metal tolerance has been broadly studied in terrestrial plants, avoidance has been less considered as a strategy to cope with soil metal pollution. Avoidance may be an effective alternative in herbaceous plants with connected clonal growth in environments having high heterogeneity in soil micro-spatial distribution of available metals and other soil conditions (i.e. organic matter). In this study, we performed a laboratory experiment on clonal growth of Solidago chilensis when exposed to copper-spiked soils (800 mg kg(-1)) at different depths (0, 2, 5 and 8 cm depth), with (20%) and without addition of organic matter to mimic contrasting microhabitats found at smelter hinterlands (i.e. open bare ground and microhabitats below shrubs). Results showed that plants grown in the 2 cm-depth Cu-spiked soils were able to growth and produce ramets and rhizomes. However, increased Cu uptake of plants determined phytotoxic effects and a reduction in clonal spread in the 5 cm- and 8 cm-depth Cu-spiked soils. Addition of organic matter to the Cu-spiked soil layers allowed clonal spread. Considering that ramet and rhizome production is decreased but not inhibited when copper pollution is restricted to the uppermost soil layer (2 cm depth) and that organic matter eliminated soil copper toxicity allowing normal clonal spread, connected clonal growth may be an effective avoidance mechanism of Solidago chilensis, particularly in environments with high heterogeneity in micro-spatial distribution of metals and organic matter in the soil profile and between microhabitats. (C) 2019 Elsevier Ltd. All rights reserved.
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    Global issues in setting legal limits on soil metal contamination: A case study of Chile
    (2022) Tapia-Gatica, Jaime; Selles, Ivan; Bravo, Manuel A.; Tessini, Catherine; Barros-Parada, Wilson; Novoselov, Alexey; Neaman, Alexander
    The establishment of legal limits for soil contamination with trace elements is a global issue that has not yet been resolved. However, the resolution of any global problem begins at the national level. In this vein, we present the case of Chile, the world's leading copper producer, where soil contamination by trace elements in mining areas has been severe. We evaluated the magnitude of the ecological and human health risks from exposure to arsenic (As), copper (Cu), zinc (Zn), and lead (Pb) in soils of the La Ligua and Petorca basins, two important mining areas in Chile. Contrary to what might be expected in soils affected by Cu mining activities, As was identified as the most hazardous element in the studied soils, both in terms of ecological and human health risks. On the other hand, Chile does not currently have specific legislation establishing legal limits on soil contamination with trace elements. Since Chile is geochemically similar to New Zealand, Mexico, and Italy, we used the limits of these three countries as benchmarks. We determined the background concentrations of As, Cu, Zn, and Pb in the soils of the two river basins under study and found that they tend to exceed the limits established by foreign laws. We also found that the differences in background elemental concentrations in the studied soils were primarily due to the varied lithology of soil-forming rocks. This means that absolute "one-limit-fits-all" values of element concentrations may not be adequate to regulate the level of soil contamination in areas affected by mining. As a fundamental first step, it is necessary to establish background soil concentrations of trace elements in each river basin in Chile. It is clear that Chile urgently needs to move from rubber-stamping foreign laws to the development of national legislation on soil metal contamination.
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    The downside of copper pesticides: An earthworm's perspective
    (2024) Schoffer, Jorge Tomas; Solari, Fiama; Petit-dit-Grezeriat, Lucas; Pelosi, Celine; Ginocchio, Rosanna; Yanez, Carolina; Mazuela, Pilar; Neaman, Alexander
    The widespread use of copper-based pesticides, while effective in controlling plant diseases, has been identified as a major source of copper contamination in soils. This raises concerns about potential adverse effects on earthworms, key players in soil health and ecosystem function. To inform sustainable pesticide practices, this study aimed to establish copper toxicity thresholds for earthworm avoidance in agricultural soils impacted by copper-based pesticides. We collected 40 topsoil samples (0-5 cm) from orchards and vineyards in the O'Higgins Region of central Chile, and 10 additional soils under native vegetation as background references. A standardized avoidance bioassay using Eisenia fetida assessed the impact of copper-based pesticides on the soils. Total copper concentrations ranged between 23 and 566 mg kg-1, with observed toxic effects on earthworms in certain soils. The effective concentration at 50% (EC50) for total soil copper, determined by Eisenia fetida's avoidance response, was 240 mg kg-1, with a 95% confidence interval of 193-341 mg kg-1. We further compared our EC50 values with existing data from agricultural soils impacted by mining activities. Interestingly, the results revealed a remarkable similarity between the thresholds for earthworm avoidance, regardless of the source of copper contamination. This observation underscores the universality of copper toxicity in agricultural ecosystems and its potential impact on soil biota. This study provides novel insights into copper toxicity thresholds for earthworms in real-world, pesticide-contaminated soils.
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    Thresholds of copper phytotoxicity in field-collected agricultural soils exposed to copper mining activities in Chile
    (2015) Verdejo, José; Ginocchio Cea, Rosanna; Sauvé, Sébastien; Salgado, Eduardo; Neaman, Alexander