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    Blowin’ in the Wind: Mapping the Dispersion of Metal(loid)s From Atacama Mining
    (2024)
    Nicolás C. Zanetta‐Colombo
    ;
    Carlos A. Manzano
    ;
    Dagmar Brombierstäudl
    ;
    FLEMING, ZOE LOUISE  
    ;
    Eugenia M. Gayo
    <jats:title>Abstract</jats:title><jats:p>The Atacama Desert’s naturally elevated metal(loid)s pose a unique challenge for assessing the environmental impact of mining, particularly for indigenous communities residing in these areas. This study investigates how copper mining influences the dispersion of these elements in the wind‐transportable fraction (&lt;75 μm) of surface sediments across an 80 km radius. We employed a multi‐pronged approach, utilizing spatial modeling to map element distributions, exponential decay analysis to quantify concentration decline with distance, regime shift modeling to identify dispersion pattern variations, and pollution assessment to evaluate impact. Our results reveal significant mining‐driven increases in surface concentrations of copper (Cu), molybdenum (Mo), and arsenic (As). Notably, within the first 20 km, concentrations peaked at 1,016 mg kg⁻<jats:sup>1</jats:sup> for Cu, 31 mg kg⁻<jats:sup>1</jats:sup> for Mo, and a remarkable 165 mg kg⁻<jats:sup>1</jats:sup> for As. Cu and Mo displayed significant dispersion, extending up to 50 km from the source. However, As exhibited the most extensive reach, traveling up to 70 km downwind, highlighting the far‐reaching ecological footprint of mining operations. Mineralogical analyses corroborated these findings, identifying mining‐related minerals in surface sediments far beyond the immediate mining area. Although pollution indices based on the proposed Local Geochemical Background reveal significant contamination across the study area, establishing accurate pre‐industrial baseline values is essential for a more reliable assessment. This study challenges the concept of “natural pollution” by demonstrating that human activities exacerbate baseline metal(loid)s levels. Expanding monitoring protocols is imperative to comprehensively assess the combined effects of multiple emission sources, including mining and natural processes, in safeguarding environmental and human health for future generations.</jats:p>
    Scopus© Citations 1  2
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    Microbial Community and Enzyme Activity of Forest Plantation, Natural Forests, and Agricultural Land in Chilean Coastal Cordillera Soils
    (2023)
    Yessica Rivas
    ;
    Humberto Aponte
    ;
    RIVERA SALAZAR, DIEGO ANDRÉS  
    ;
    Francisco Matus
    ;
    Oscar Martínez
    <jats:p>Despite the global expansion of forest plantations in Chile, their effect on biology properties of soil has still been only scarcely studied. Land use change in the Chilean Coastal Cordillera (36° to 40° S) is mainly attributed to the conversion of native forest to agriculture and forest plantations (Eucalyptus globulus and Pinus radiata de Don). The aim of this paper was to evaluate the changes in microbial composition (PCR-DGGE) and enzyme activity after the substitution of a native forest (e.g., Nothofagus spp.) by fast-growing exotic species and cropping. The most important factors that influence the abundance and diversity of bacteria and the fungi community were the soil organic matter (SOM) content, phosphorous (P-Olsen), calcium (Ca), boron (B), and water-holding capacity. These variables can better predict the microbial community composition and its enzymatic activity in the surface Ah horizon. Land use change also affected chemical soil properties of biogeochemical cycles. However, to deeply understand the connection between chemical and physical soil factors and microbial community composition, more research is needed. On the other hand, the expansion of forest plantations in Chile should be subject to legislation aimed to protect the biological legacy as a strategy for forest productivity as well as the soil microbial biodiversity.</jats:p>
      2Scopus© Citations 5
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    Static and Dynamic Loads on a Shallow Circular Tunnel: Practical Design Considerations
    (2023)
    MEDINA MOLINA, LUIS FELIPE
    ;
    GUTIÉRREZ VEGA, CARLOS
    ;
    LYON AUSENSI, BENJAMÍN
    ;
    CANDIA AGUSTI, GABRIEL ALFONSO  
      7
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    Geotechnical Aspects of the 2015 M<sub>w</sub> 8.3 Illapel Megathrust Earthquake Sequence in Chile
    (2017)
    CANDIA AGUSTI, GABRIEL  
    ;
    Gregory P. de Pascale
    ;
    Gonzalo Montalva
    ;
    Christian Ledezma
    <jats:p> The 2015 Illapel earthquake sequence in Central Chile, occurred along the subduction zone interface in a known seismic gap, with moment magnitudes of M<jats:sub> w</jats:sub> 8.3, M<jats:sub> w</jats:sub> 7.1, and M<jats:sub> w</jats:sub> 7.6. The main event triggered tsunami waves that damaged structures along the coast, while the surface ground motion induced localized liquefaction, settlement of bridge abutments, rockfall, debris flow, and collapse in several adobe structures. Because of the strict seismic codes in Chile, damage to modern engineered infrastructure was limited, although there was widespread tsunami-induced damage to one-story and two-stories residential homes adjacent to the shoreline. Soon after the earthquake, shear wave measurements were performed at selected potentially liquefiable sites to test recent V<jats:sub> S</jats:sub>-based liquefaction susceptibility approaches. This paper describes the effects that this earthquake sequence and tsunami had on a number of retaining structures, bridge abutments, and cuts along Chile's main highway (Route 5). Since tsunami waves redistribute coastal and near shore sand along the coast, liquefaction evidence in coastal zones with tsunami waves is sometimes obscured within minutes because the tsunami waves entrain and deposit sand that covers or erodes evidence of liquefaction (e.g., lateral spread or sand blows). This suggests that liquefaction occurrence and hazard may be under estimated in coastal zones. Importantly, the areas that experienced the greatest coseismic slip, appeared to have the largest volumes of rockfall that impacted roads, which suggests that coseismic slip maps, generated immediately after the shaking stops, can provide a first order indication about where to expect damage during future major events. </jats:p>
    Scopus© Citations 17  2
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    Scopus© Citations 31  1
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    Scopus© Citations 9  8
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    Scopus© Citations 10  4