Accumulation of As, Ag, Cd, Cu, Pb, and Zn by Native Plants Growing in Soils Contaminated by Mining Environmental Liabilities in the Peruvian Andes.

The capability of native plant species grown in polluted post-mining soils to accumulate metals was evaluated in view of their possible suitability for phytoremediation. The study areas included two environmental liabilities in the Cajamarca region in the Peruvian Andes. The content of As, Ag, Cd, Cu, Pb, and Zn was determined in individual plant organs and correlated with soil characteristics. The degree of the pollution depended on the metal with results ranging from uncontaminated (Cd) to moderately (Zn), strongly (As, Cu), and extremely contaminated (Pb, Ag) soils. The metals were mainly present in the fractions with limited metal mobility. The bioaccumulation of the metals in plants as well the translocation into overground organs was determined. Out of the 21 plants evaluated, Pernettya prostrata and Gaultheria glomerate were suitable for Zn, and Gaultheria glomerata and Festuca sp. for Cd, phytostabilization. The native species applicable for Cd phytoremediation were Ageratina glechonophylla, Bejaria sp., whereas Pernettya prostrata Achyrocline alata,Ageratina fastigiate, Baccharis alnifolia, Calceolaria tetragona, Arenaria digyna, Hypericum laricifolium, Brachyotum radula, and Nicotiana thyrsiflora were suitable for both Cd and Zn. None of the studied plants appeared to be suitable for phytoremediation of Pb, Cu, As and Ag.

Evaluation of copper tailing amendments through poultry waste and ammonium nitrate.

In this study, two amendments, poultry waste and ammonium nitrate, were evaluated to condition and stabilize a mine tailing and thus help the vegetation cover settle. Individually, ammonium nitrate was tested as a nitrogen source and chicken bone ash as a phosphate source. For this, laboratory tests were made on soil columns from the area to be remediated. The mobility and availability of metals and nutrients were determined by analyzing their leachates chemically. The results showed that the use of chicken bone ash decreases soluble metal concentrations, particularly in Fe and soluble Mn. On the other hand, experimental conditions proved that the acidification produced by ammonium nitrate nitrification does not significantly increase the lechate metal content. Therefore, its use for fertilization does not involve phytotoxicity risks. Regarding the availability of macronutrients as well as trace elements, the results showed that the concentrations lie within the ranges suitable for plant nutrition. So, the treatments are effective both for fertilization and phytoremediation.

Making Paving Stones from Copper Mine Tailings as Aggregates.

Copper mining, the central axis of Chile's economic development, produces a large number of tailings, which become a potential environmental risk. This study aims to evaluate the mechanical properties resulting from the making of Portland cement mixtures with tailings as aggregates so that they can be eventually used in paving stones for building inactive tailings dams. Tailings coming from two dams at a concentration plant located in Taltal (Chile) were used. Currently, Dam 1 is inactive, while Dam 2 is active. The tailings samples obtained from both dams were granulometrically characterized by sieving. In addition, pH, humidity, Eh, and mineralogical assays (sulfides, oxides, sulfates, carbonates, phosphates, and silicates) were measured. The fines content of the tailings from Dams 1 and 2 with a sieve size of N°200 ASTM were 76.2% and 29.6%, respectively. Therefore, owing to their high percentage of fines, they cannot be as used as concrete aggregates. Aggregates must contain a maximum percentage of fines so that mortars and concrete can meet Chilean standards. In this paper, to comply with a 7% and 15% fines content lower than 0.075 mm, tailings materials were mixed with conventional aggregates containing very little fines. In addition, a reference mixture was made with only tailings aggregates with and without a superplasticizer additive. To measure the mixtures of cement, aggregates, and tailings, bending and compression strength assays were made of the specimens after a 28-day curing, according to the Chilean standard. The results of the study show that the addition of only part of the tailings to the mixture increases bending strength by 26% and compression strength by 180% compared with the reference mortar, with a fines content lower than 0.075 mm in the 7% mixture, thus allowing paving stone manufacture with tailings materials. In addition, it was possible to increase the workability of the reference mixture by using superplasticizers as additives.

Prokaryotic and eukaryotic community structure affected by the presence of an acid mine drainage from an abandoned gold mine.

The acid mine drainage that originates in the abandoned gold mine in San Luis, Argentina, is released into La Carolina stream. The aim of this study was to determine the influence of this mine drainage on the physicochemical parameters of the area studied and on both prokaryotic and eukaryotic community structure. In addition, specific relationships between microbial taxonomic groups and physicochemical parameters were established. The drainage that flows into La Carolina stream acidifies the stream and increases its sulfate, Zn, Cd and Te concentrations. Microbial analysis showed that prokaryotic community structure is mainly affected by pH values. Actinobacteria and Gammaproteobacteria were abundant in samples characterized by low pH values, while Nitrospirae, Chloroflexi, Deltaproteobacteria, Thaumarchaeota and Euryarchaeota were associated with high concentrations of heavy metals. Otherwise, Alphaproteobacteria was present in samples taken in sunlit areas. Regarding eukaryotic community structure, the sunlight had the greatest impact. Inside the mine, in the absence of light, fungi and protists members were the most abundant microorganisms, while those samples taken in the presence of light displayed algae (green algae and diatoms) as the most abundant ones. After receiving the mine drainage, the stream showed a decrease in the diatom abundance and green algae predominated.

La prevención y mitigación de los riesgos de los pasivos ambientales mineros (PAM) en Colombia: una propuesta metodológica

La minería colombiana ha adquirido una gran importancia en la economía del país. No obstante su relevancia, las repercusiones ambientales y sociales no son insignificantes; por el contrario, los alcances del deterioro que genera han exigido la adopción de políticas públicas que los contrarresten. El país está a la zaga en América Latina en política ambiental, particularmente en lo referente a la gestión de los llamados pasivos ambientales mineros y al cierre de minas abandonadas, inactivas, paralizadas o huérfanas, que requieren medidas de mitigación o remediación; además del manejo del riesgo de sus efectos negativos actuales y futuros. Para una adecuada gestión de estos pasivos es conveniente el diseño y aplicación de una matriz de riesgo que incorpore las buenas prácticas mineras, para así mitigar y prevenir mayores daños en el entorno socio-ambiental.

The Colombian mining has acquired an important role in the economy of the country. Despite its relevancy, environmental and social impacts are not insignificant, on the contrary the scope of this deterioration has demanded the adoption of public policies to counteract it. The country is lagging behind in Latin America in environmental policy particularly as regards manage of so called mining environmental liabilities and abandoned, inactive, paralyzed or orphaned mine closure requiring measures to mitigate them or remedy them, in addition to the management of risks of effects both current and future. For a suitable management of these liabilities, it is convenient the design and application of a risk matrix incorporating good mining practices in order to mitigate and prevent further damage to socio-environmental surroundings.

Mineração colombiana tornou-se cada vez mais importante na economia do país. Apesar de sua relevância, impactos ambientais e sociais não são insignificantes; pelo contrário, o alcance da deterioração que gera exigiram a adoção de políticas públicas que neutralizam. O país está ficando para trás na América Latina na política ambiental, particularmente em relação à gestão de passivos ambientais de mineração e fechamento de minas abandonadas, inativos ou órfão paralisadas, exigindo mitigação ou remediação conhecido; além da gestão de riscos de efeitos negativos atuais e futuras. Para uma gestão adequada desses passivos é conveniente para a concepção e implementação de uma matriz de risco para incorporar as boas práticas de mineração, a fim de mitigar e evitar mais danos ao ambiente sócio-ambientais.