Jorge Oyarzún

Stakeholder participation within the public environmental system in Chile: Major gaps between theory and practice

The main objective of this paper is to present a critical analysis of the stakeholder participation process within the Environmental Impact Assessment System in Chile, after ca. 14 years of being enforced. This analysis is sustained by the description and analysis of the stakeholder participation possibilities in a representative rural area of North-Central Chile. The Environmental Basis Act 19300, enacted in 1994, considers the participation of the local community in the environmental impact assessment of new projects. However, this possibility is very limited and difficult to exert, often resulting in frustration for the participants. This is due to a number of reasons, such as the imbalance of resources and knowledge among the majority of participating communities and project proponents, the complexity and administrative and legal constraints to participation, and the dominant interest of the Central Government in approving investments, specifically in energy and natural resources related projects, which generate wealth and jobs. Also, the States rush to develop Internet-based communication and management systems has built a barrier for poor, traditional communities. This factor is clearly reflected in the case study considered. Results show that there is generally a significant lack of knowledge about institutions and participation tools. From this base, we intend to raise concern on these selected aspects that could be addressed to improve the effectiveness of the existing framework, both in Chile and in other developing countries, where immature environmental impact assessment and public management systems face similar pressures in relation to the sustainable use of their natural resources. Finally, some basic steps are proposed in order to make the community participation an effective tool for sustainable development.

Application of water quality indices and analysis of the surface water quality monitoring network in semiarid North-Central Chile

Surface water quality has increasing importance worldwide and is particularly relevant in the semiarid North-Central Chile, where agriculture and mining activities are imposing heavy pressure on limited water resources. The current study presents the application of a water quality index in four watersheds of the 29°–33°S realm for the period 1999–2008, based on the Canadian Council of Ministers for the Environment approach and the Chilean regulation for irrigation water quality. In addition, two modifications to the index are tested and a comprehensive characterization of the existing monitoring network is performed through cluster analysis. The basins studied show fairly good water quality in the overall, specially the Limarí basin. On the other hand, the lower index values were obtained for the headwaters of Elqui, associated with the El Indio mining district. The first modification of the indicator (i.e., to consider parameters differentially according to their effect on human health or the environment) did not produce major differences with respect to the original index, given the generally good water quality. The second modification (i.e., to consider as threshold values the more restrictive figures derived from a set of regulations) yielded important differences in the indicator values. Finally, an adequate characterization of the monitoring network was obtained. The results presented spatial coherence and the information can be used as a basis for the optimization of the monitoring network if required.

Contributions of the different water sources to the Elqui river runoff (northern Chile) evaluated by H/O isotopes

We present the results of an isotope (2H and18O) and hydrogeochemical study in order to constrain the origin, recharge, and evolution of the surface and groundwater in the arid Andean realm of the Elqui watershed. The results of2H and18O analyses of water samples obtained during our summer and winter campaigns indicate a generally meteoric origin of the river and spring waters of the watershed. The isotope signature of water of the Elqui river and its tributaries as well as that of groundwater in the coastal region fits the2H‒18O relation of δ2H=7.61δ18O+6.1. A relatively fast discharge and a quasi-closed catchment area can be asserted for water along the river flow path. The tributaries from the more arid coastal area, north of the Elqui river, differ in their isotopic signature due to evaporation and hydrochemically due to interactions with the strongly altered and fractured volcanic rocks of the basement. In the Andean zone, the18O-enriched hydrothermal spring of Baños del Toro exhibits the influence of water–rock interaction processes. The chemistry of the river water changes from sulphate- to chloride-rich along the river course from the high Andean mountains to the coast. The sulphate-rich character of these Andean waters reflects their passage through sulphide-rich rock massifs that were subjected to strong oxidation processes in the near superficial environment. This sulphate signature is enforced by past and present mining of precious metal epithermal deposits (e.g. those of El Indio-Tambo Au–Cu–As district), in which mineralised zones were developed during a series of Miocene magmatic-hydrothermal episodes in the Andean realm. Owing to the proximity of the lower Elqui river waters and its tributaries to the Pacific coast, the chloride character may be induced by agricultural and marine (sea spray, fog) sources. Generally, the main source of the Elqui river water is mainly attributed to surface runoff and less to contributions from the basement fractured aquifer.

Water Quality Assessment of the Mining-Impacted Elqui River Basin, Chile

Multivariate data analysis techniques were used to identify the interrelationships between the physical–chemical analyses of 22 parameters sampled monthly from 1991 to 2007 at 16 monitoring stations along the Elqui river and its tributaries to characterize the scale of the geogenic and anthropogenic impacts on the river’s water quality. Principal component analysis was used to identify the differences and similarities between variables in the watershed. Factorial indices, computed to highlight the sections of the river and tributaries more influenced by hydrothermal, mining or agricultural activities, made it possible to synthesize groups of parameters with similar characteristics into a single value.ZusammenfassungVon 1991 bis 2007 wurden an 16 Beobachtungstationen entlang des Elqui-Flusses und seinen Zuflüssen monatlich 22 physiko-chemische Parameter gemessen. Der Grad geogener und anthropogener Einflüsse auf die Wasserqualität wurde mit multivariaten Analysen untersucht. Hauptkomponentenanalyse wurde angewendet, um Unterschiede und Ähnlichkeiten zwischen Variablen in dem Wassereinzugsgebiet zu identifizieren. Um Abschnitte des Flusses und seiner Zuflüsse mit stärkerem Einfluß hydrothermaler, bergaulicher oder landwirtschaftlicher Aktivitäten hervorzuheben, wurden faktorielle Kennzahlen berechnet. Damit war es möglich, Gruppen von Parametern ähnlicher Besonderheiten in einen Einzelwert zusammenzuführen.ResumenSe utilizaron técnicas de análisis multivariante para identificar las relaciones entre los análisis de 22 parámetros fisicoquímicos obtenidos mensualmente desde 1991 hasta 2007 en 16 estaciones de monitorio a lo largo del Río Elqui y sus tributarios, en función de caracterizar de la escala de los impactos geogénicos y antropogénicos sobre la calidad del agua del río. El análisis de componentes principales (PCA) fue usado para identificar las diferencias y similitudes entre variables de la cuenca. Los índices factoriales, estimados para destacar las zonas del río y sus tributarios más influida por las actividades minerales, hidrotérmicas o agrícolas, permitieron reunir grupos de parámetros con similares características dentro de un solo valor.抽象化学水质监测指标之间的关系,以研究地质成因和人类活动作用对流域水质的影响程度。利用主成分分析法(PCA)识别了流域内各变量之间的差异与相似性。利用因子分析突出了埃尔基河及其支流受热液、采矿和农业活动的影响程度,使具有相似特征的多元变量转化为单一变量成为可能。

Massive Volcanism in the Altiplano-Puna Volcanic Plateau and Formation of the Huge Atacama Desert Nitrate Deposits: A Case for Thermal and Electric Fixation of Atmospheric Nitrogen

The origin of the giant nitrate deposits of the Atacama Desert (Chile) is a controversial issue. At a global scale, the Atacama Desert nitrates constitute a rare singularity because no equivalent deposits are found anywhere else. Previous hypotheses for origin of the Chilean nitrates have failed to recognize the importance of the 70,000 km2 Late Miocene to present Altiplano-Puna volcanic plateau (APVP), only 50-200 km eastward from the nitrate deposits. We argue that the extrusion of a volume of over 104 km3 of pyroclastic rocks at the APVP may have created the conditions to induce thermal and electric fixation of an estimate of 2800 Mt of atmospheric nitrogen in the form of NO3. This figure exceeds the amount of nitrogen required to account for the Atacama Desert nitrate deposits. Thus, the origin of the nitrate deposits may be found in an unusual combination of hyper-arid conditions (vital for the final stabilization and preservation of the NaNO3 mineral phase) and massive volcanism (key to fixation of large amounts of atmospheric nitrogen). Volcanic eruptions have far more environmental implications than usually assumed, decisively contributing to the global cycles of many chemical elements and compounds. For example, nitrogen fixation by volcanic activity could also explain the current excess of NOx compounds in the pristine marine atmosphere of the mid-Pacific, a realm conspicuously surrounded by the worlds largest concentration of active volcanoes.

Natural factors and mining activity bearings on the water quality of the Choapa basin, North Central Chile: insights on the role of mafic volcanic rocks in the buffering of the acid drainage process.

This contribution analyzes water chemical data for the Choapa basin, North Central Chile, for the period 1980–2004. The parameters considered are As, Cu Fe, pH, EC, SO

Strong metal anomalies in stream sediments from semiarid watersheds in northern chile: when geological and structural analyses contribute to understanding environmental disturbances.

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Evaluating piezometric trends using the Mann-Kendall test on the alluvial aquifers of the Elqui River basin, Chile

, Cl − 1, and HCO

Surface water quality in a sulfide mineral‐rich arid zone in North‐Central Chile: Learning from a complex past, addressing an uncertain future

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Plate Interactions, Evolving Magmatic Styles, and Inheritance of Structural Paths: Development of the Gold-Rich, Miocene El Indio Epithermal Belt, Northern Chile

, from samples taken in nine monitoring stations throughout the basin. Results show rather moderate contents of As, Cu, and Fe, with the exception of the Cuncumén River and the Aucó creek, explained by the influence of the huge porphyry copper deposit of Los Pelambres and by the presence of mining operations, respectively. When compared against results obtained in previous researches at the neighboring Elqui river basin, which host the El Indio Au–Cu–As district, a much reduced grade of pollution is recognized for the Choapa basin. Considering the effect of acid rock drainage (ARD)-related Cu contents on the fine fraction of the sediments of both river basins, the differences recorded are even more striking. Although the Los Pelambres porphyry copper deposit, on the headwaters of the Choapa river basin, is between one and two orders of magnitude bigger than El Indio, stream water and sediments of the former exhibit significantly lower copper contents than those of the latter. A main factor which may explain these results is the smaller degree of H + -metasomatism on the host rocks of the Los Pelambres deposit, where mafic andesitic volcanic rocks presenting propylitic hydrothermal alteration are dominant. This fact contrast with the highly altered host rocks of El Indio district, where most of them have lost their potential to neutralize ARD.Ces pages resument les resultats d’une decennie de recherches geochimiques dans les trois bassins-versants de la region de Coquimbo (centre-nord du Chili). L’extraction miniere et l’agriculture en sont les principales activites economiques. Les etudes concernent la geochimie des eaux et des sediments fluviaux et les mesures de mercure atmospherique. Les principaux resultats indiquent les concentrations elevees des ions cuivre, arsenic et zinc dans la fraction fine des sediments fluviaux du bassin-versant du rio Elqui (le plus au nord), concentrations qui atteignent des moyennes de l’ordre de 0,1 a 0,2 % dans le cas du cuivre. Ces chiffres sont en mettre en relation avec le drainage acide du secteur minier de El Indio (or, cuivre, arsenic), situe tout a fait a l’amont du bassin et entoure par une zone d’alteration hydrothermale et argilique avancee. Y contribue egalement l’erosion des deblais miniers laisses sur les flancs des vallees par une activite miniere cuprifere a petite et moyenne echelle. La plus grande exploitation miniere de la region de Coquimbo, Los Pelambres, qui exploite un gisement porphyrique de cuivre-(molybdene) de classe mondiale, est situee a l’amont du bassin-versant du rio Choapa, le plus meridional. Un resultat inattendu fut que les eaux et les sediments fins du Choapa ne presentent aucune anomalie concernant les ions cuivre et les ions molybdene. Ceci peut etre explique par le fait que les roches de ce secteur sont de caractere magmatique basique et n’ont ete que faiblement affectees que par une alteration hydrothermale, ce qui a permis la neutralisation d’un drainage acide.