Browsing by Author "Neaman, A."

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    Efficacy of fresh and air-dried biosolids as amendments for remediation of acidic and metal-polluted soils: A short-term laboratory assay
    (2013) Ginocchio, R.; Carcamo, V.; Bustamante, E.; Trangolao, E.; de la Fuente, L. M.; Neaman, A.
    Biosolids have been used as amendments on mine degraded soils for in situ immobilization of metals, neutralization, and improvement of nutritional, microbiological, and physical characteristics to reestablish a self-sustaining plant community. Fresh and air-dried biosolids have been used but dried ones are preferred as they are cheaper to transport, contain less pathogens and are much easier to handle. The same efficacy has been assumed for both biosolids. The study evaluated the effects of fresh and air-dried biosolids on physical, chemical and microbiological characteristics of an acidic and metal/As-rich soil of the Puchuncav valley, central Chile, and on plant yield under laboratory conditions. Two doses of each biosolids were used (50 and 100 ton ha(-1), dry weight). Fresh and air-dried biosolids similarly increased organic matter, total nitrogen (N) and available N and phosphorous contents of study soil. However, air-dried biosolids exhibited lower field capacity and higher wilting point, salinity, higher levels of dissolved organic carbon, concentrations of total dissolved copper and zinc, and lower activity of free Cu2+ ions in pore water. Basal respiration was significantly increased by incorporation of biosolids into soils, irrespective of being fresh or air-dried ones. In terms of aerial plant productivity, fresh biosolids and low doses of air-dried biosolids significantly increased this characteristic. However, high doses of air-dried biosolids limited aerial biomass and root cover, probably due to soil salinity and water stress. Therefore, fresh biosolids are suggested for remediation of this mine degraded soils.
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    Monitoring of Chemical Species in Soils, Waters and Plants Near the Active Copper Mine Tailing Dam Ovejeria (Central Chile)
    (2024) Tapia, Y.; Garcia, A.; Acuna, E.; Salazar, O.; Casanova, M.; Najera, F.; Kremer, C.; Castillo, B.; Joven, A.; Diaz, O.; Pastene, R.; Antilen, M.; Cornejo, P.; Neaman, A.
    Chile, the world's largest copper producer, generates massive amounts of mine tailings that are a source of ongoing environmental concern for local communities. The main objective of this work is to evaluate the concentration of As, Cd, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Zn and SO42- in soils, water and vegetation in the communities surrounding the Cu Ovejeria mine tailings dam, in central Chile. Soils, water and plants samples were collected from the towns of Chacabuco, Huechun, Huertos Familiares, Punta Peuco and Santa Matilde, which are located at 3 to 8 km from the mine tailings site, operated by CODELCO since 1999. The results showed that the levels of metals/metalloids and SO42- in water (pH 6.7-7.9) met both WHO limits and Chilean water quality standards for multiples uses. In soil (pH 7.7-8.4), total and available concentrations of metals/metalloids did not exceed international reference values. Plants with acceptable levels of metals and S were Citrus limon, Eucalyptus, Schinus molle, Prunus persica, Medicago sativa, Citrus sinensis and Ficus carica. The only species with Fe content well above the reference value and with high concentrations of other metals (Cu, Mn, Mo and Pb) was Acacia caven. The concentrations of chemical species determined between 2015 and 2018, in different media and locations near the active Cu tailings dam Ovejeria, in central Chile, allow to conclude that in general the levels are comparable to national and international references and do not indicate contamination.
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    Rising Copper Exposure Effects on Nutrient Uptake in Two Species with Distinct Copper Tolerance
    (2021) Selles, I.; Neaman, A.; Krutyakov, Yu. A.; Ginocchio, R.
    Excessive copper concentrations affect nutrient uptake in sensible species. However, the effects of copper on nutrient uptake in tolerant species have not been studied equally well. Thus, the main objective of this study was to determine the effect of rising Cu exposure on nutrient uptake rates and root/shoot nutrient contents in two species with distinct copper tolerance: Acacia caven (Mol.) Mol. and Helianthus annuus L. To this end, a hydroponic experiment was conducted. Copper treatments were applied at concentrations of 0, 2.0, 3.9, 7.9, and 15.7 mu M. Relative root elongation was chosen as the endpoint for Cu toxicity assessment. The results of our study demonstrate that A. caven and H. annuus differ greatly in their tolerance to Cu. Copper concentration in the solution associated with the calculated EC25 was found to be six times higher in A. caven (15 mu M) than in H. annuus (2.3 mu M). When effective concentrations were instead based on the measured root Cu concentrations, the difference observed was ten times greater (1044 and 98 mg/kg for A. caven and H. annuus, respectively). Both species showed equal Cu uptake kinetics, with root absorbing power (alpha) of 7.5 +/- 0.7 x 10(-6) and 7.8 +/- 0.5 x 10(-6) cm s(-1) for A. caven and H. annuus, respectively. Rising Cu concentrations in the exposure solution progressively diminished the influx of Ca into the roots of H. annuus, whereas no significant effect was noted for A. caven.
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    Root Elongation Method for the Quality Assessment of Metal-Polluted Soils
    (2020) Prudnikova, E. V.; Neaman, A.; Terekhova, V. A.; Karpukhin, M. M.; Vorobeichik, E. L.; Smorkalov, I. A.; Dovletyarova, E. A.; Navarro Villarroel, C.; Ginocchio Cea, Rosanna; Peñaloza, P.
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    Thresholds of copper toxicity to lettuce in field-collected agricultural soils exposed to copper mining activities in Chile
    (2016) Verdejo, J.; Ginocchio Cea, Rosanna; Sauvé, S.; Mondaca, P.; Neaman, A.
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    Use of Zinc Carbonate Spiking to Obtain Phytotoxicity Thresholds Comparable to Those in Field-Collected Soils
    (2020) Grigorita, G.; Neaman, A.; Brykova, R.; Brykov, V. A.; Morev, D. V.; Ginocchio Cea, Rosanna; Paltseva, A. A.; Vidal, K.; Navarro Villarroel, C.; Dovletyarova, E. A.