J. Pamplona

Geochemistry of rare earth elements in a passive treatment system built for acid mine drainage remediation

Rare earth elements (REE) were used to assess attenuation processes in a passive system for acid mine drainage treatment (Jales, Portugal). Hydrochemical parameters and REE contents in water, soils and sediments were obtained along the treatment system, after summer and winter. A decrease of REE contents in the water resulting from the interaction with limestone after summer occurs; in the wetlands REE are significantly released by the soil particles to the water. After winter, a higher water dynamics favors the AMD treatment effectiveness and performance since REE contents decrease along the system; La and Ce are preferentially sequestered by ochre sludge but released to the water in the wetlands, influencing the REE pattern of the creek water. Thus, REE fractionation occurs in the passive treatment systems and can be used as tracer to follow up and understand the geochemical processes that promote the remediation of AMD.

Metal Uptake by Native Plants and Revegetation Potential of Mining Sulfide-Rich Waste-Dumps

Waste dumps resulting from metal exploitation create serious environmental damage, providing soil and water degradation over long distances. Phytostabilization can be used to remediate these mining sites. The present study aims to evaluate the behavior of selected plant species (Erica arborea, Ulex europaeus, Agrostis delicatula, and Cytisus multiflorus) that grow spontaneously in three sulfide-rich waste-dumps (Lapa Grande, Cerdeirinha, and Penedono, Portugal). These sites represent different geological, climatic and floristic settings. The results indicate distinctive levels and types of metal contamination: Penedono presents highest sulfate and metal contents, especially As, with low levels of Fe. In contrast, at Lapa Grande and Cerdeirinha Fe, Mn, and Zn are the dominant metals. In accordance, each waste dump develops a typical plant community, providing a specific vegetation inventory. At Penedono, Agrostis delicatula accumulates As, Pb, Cu, Mn, and Zn, showing higher bioaccumulation factors (BF) for Mn (32.1) and As (24.4). At Cerdeirinha, Ulex europaeus has the highest BF for Pb (984), while at Lapa Grande, Erica arborea presents high BF for Mn (9.8) and Pb (8.1). Regarding TF, low values were obtained for most of the metals, especially As (TF < 1). Therefore, the results obtained from representative plant species suggest appropriate behavior for phytostabilization measures.

Geochemistry and mineralogy of ochre-precipitates formed as waste products of passive mine water treatment

ABSTRACT Passive systems with constructed wetlands are designed to simulate natural attenuation processes in order to treat mine water in a long-term and cost-effective manner. In this way, they are especially appropriate to treat mine water discharging from abandoned mines. This paper presents geochemical and mineralogical data obtained from a recently constructed passive system in the Jales abandoned mine, north Portugal. It shows the role of fresh ochre-precipitates, formed as waste products from the neutralization process, in the retention of trace elements. Chemical analysis of these waste products revealed strong enrichment factors for metals and arsenic, relative to the water from which they precipitate. The mineralogical study shows that ochre-precipitates are poorly ordered iron-rich material, such as ferrihydrites, that occur as small spherical aggregates (<0.1 μm in diameter). Heating experiments on these precipitates gave rise to hematite and to a crystalline arsenate. This provides evidence for the scavenging of arsenic by means of a precursor arsenic-rich amorphous compound. The results reveal that ochre-precipitates are wastes of environmental concern, which should be taken into account when considering the possibilities for reuse or disposal.

ENVIRONMENTAL BEHAVIOR: A COMPARATIVE STUDY BETWEEN BRAZILIAN AND PORTUGUESE STUDENTS

Although undergraduate students have great access to environmental information, it does not mean that an environmental behavior is being developed. With the use of a scale applied to 1035 university students from Brazil and Portugal, it was examined how the environmental behavior of these students is structured. Using multivariate statistical techniques, it was verified that there is a similarity in the environmental behavior of both groups, with environmental beliefs being manifested by an opposition to the anthropocentric view. The environmental attitudes have the concerns related to the environment as their predecessor. These concerns influence the option to control economic growth, which is reinforced by the ecocentric point of view of the respondents and is manifested by the perspective of a decrease in production and in consumption as well as the promotion of welfare. Although there is a tendency, the option for green consumption is not fully accomplished.

Ductile shear zones

European Union through the European Regional Development Fund, based on COMPETE 2020 (Programa Operacional da Competitividade e Internacionalizacao), project ICT (UID/GEO/04683/ 2013) with reference POCI-01-0145-FEDER-007690 and national funds provided by Fundacao para a Ciencia e a Tecnologia.“Tabular or sheetlike, planar or curviplanar zones in which rocks are more highly strained than rocks adjacent to the zone” are called ductile shear zones. Identification and study of ductile shear zones are important since major plate boundaries are defined by such shear zones. We need to study such zones since along them partially molten rocks can flow. Secondly, viscous dissipation related to such zones has been investigated. The ductile shear sense/sense of movement from such zones can be deciphered mainly from asymmetric sigmoid, parallelogram and lenticular clasts and intrafolial folds. See Passchier and Trouw for review on ductile shear zones. In addition to such shear sense indicators, this chapter also presents near-symmetric clasts that form possibly within shear zones but that do not give the shear sense.