Dispersion of metals and arsenic from the tailings of an abandoned mine in Sierra of Madrid

The extraction and processing of minerals produce significant environmental impacts that last long after mining operations have ended. Abandoned mines provide obvious sources of contamination by metals and arsenic in surrounding areas. These areas typically support sparse vegetation, so weather events, typical of Mediterranean environments such as heavy rains, can drag metals and metalloids, in a more or less available form for vegetation, as in solution and suspension to accumulate in lower lands. In this study, the area affected by a copper mine, abandoned early last century in the Sierra de Madrid, was sampled. Soil properties such as pH, EC, total OM and texture were analyzed. Furthermore, the BCR (Bureau Community of Reference) fractionation of metals was carried out in order to evaluate the weathering of the starting materials and the selective movement of different fractions along the slope . Metals and arsenic were detected beyond the mine limits, in areas where water flows in a preferential way. Results showed high concentrations and readily extractable Cu and As, which may suggest potential bioavailability for organisms and may create an environmental risk and potential human exposure what results in a health risk for the population

Physical characterization of growing media using standard methods (CEN)- Limitations of Applicability for pine bark and vermiculite

CEN standards have helped to harmonize analytical methods for substrate analysis.Though, for special substrates or constituents the applicability might be Iimited. In this paper a comparative study of implementation of CEN standards to samples of pine bark and vermiculite has been carried out. For composted pine bark, an elongation of the equilibrium period up to 72 instead of 48 hours might increase the accuracy of determinations physical parameters according to EN 13041. For vermiculite, we suggest pycnometry as a feasible technique for the determination of particle density (PD), as the determination of organic matter (OM) as requested by EN 13041 for the calculation of the PD seems not to be applicable for this kind of material

Effect of magnetite nanoparticles on heavy metals behavior in contaminated soils

The extraction and processing of minerals produce significant environmental impacts that last long after mining operations have ended. Abandoned mines provide obvious sources of contamination by metals and arsenic in surrounding areas. These areas typically support sparse vegetation, so weather events, typical of Mediterranean environments such as heavy rains, can drag metals and metalloids, in a more or less available form for vegetation, as in solution and suspension to accumulate in lower lands. In this study, the area affected by a copper mine, abandoned early last century in the Sierra de Madrid, was sampled. Soil properties such as pH, EC, total OM and texture were analyzed. Furthermore, the BCR (Bureau Community of Reference) fractionation of metals was carried out in order to evaluate the weathering of the starting materials and the selective movement of different fractions along the slope . Metals and arsenic were detected beyond the mine limits, in areas where water flows in a preferential way. Results showed high concentrations and readily extractable Cu and As, which may suggest potential bioavailability for organisms and may create an environmental risk and potential human exposure what results in a health risk for the population

Temporal behavior and processing of the LiDAR signal in fog

The interest in LiDAR imaging systems has recently increased in outdoor ground-based applications related to computer vision, in fields like autonomous vehicles. However, for the complete settling of the technology, there are still obstacles related to outdoor performance, being its use in adverse weather conditions one of the most challenging. When working in bad weather, data shown in point clouds is unreliable and its temporal behavior is unknown. We have designed, constructed, and tested a scanning-pulsed LiDAR imaging system with outstanding characteristics related to optoelectronic modifications, in particular including digitization capabilities of each of the pulses. The system performance was tested in a macro-scale fog chamber and, using the collected data, two relevant phenomena were identified: the backscattering signal of light that first interacts with the media and false-positive points that appear due to the scattering properties of the media. Digitization of the complete signal can be used to develop algorithms to identify and get rid of them. Our contribution is related to the digitization, analysis, and characterization of the acquired signal when steering to a target under foggy conditions, as well as the proposal of different strategies to improve point clouds generated in these conditions.This work was supported by the Spanish Ministry of Science and Innovation (MICINN) under the project PID2020-119484RB-I00. The first author gratefully acknowledges the Universitat Politècnica de Catalunya and Banco Santander for the financial support of her predoctoral research grant.Peer ReviewedPostprint (author's final draft

Phytoextraction of heavy metals from mine soils using hyperaccumulator plants.

Phytoextraction is an environmental-friendly and cost-effective technology that uses metal hyperaccumulator plants to remove heavy metals from soils. The metals are absorbed by the roots, transported and accumulated in the aerial parts of the plants, which can be harvested and eliminated. The aim of this work was to study some hyperaccumulator species that could be useful to decontaminate mine soils and also to investigate the bioavailability and uptake of these metals by plants with the addition of organic amendments. Pot experiments were performed with soil samples collected from two mining areas in the north of Madrid, where there was an intense mining activity more than 50 years ago. Three species (Thlaspi arvense, Brassica juncea and Atriplex halimus) were grown under controlled conditions in pots filled with contaminated soils mixed with 0 Mg, 30 Mg and 60 Mg per hectare of two different organic amendments: a commercial compost made of pine bark, peat and wood fiber and other made of horse and sheep manure and wood fiber. Plants were harvested at the end of their crop cycle and were digested in order to measure metal concentration (Zn, Cu and Cd) in roots and shoots. Highest plant metal concentration was observed in pots treated with pine bark amendment and with pure soil due to an increase in metal bioavailability with decreasing pH. Also in those treatments the total plant biomass was lower, even some plants could not germinate. On the contrary, there was a lower metal concentration in plant tissues of pots with manure because its higher pH whereas plant growth was significantly larger so there was an incresing amount of metals removed from soil by plants. Comparing the three species results indicate a higher total metal uptake in A. halimus than B. juncea and T. arvense. In conclusion, results show that pH affects metal bioavailability and uptake by hyperaccumulator plants. Addition of organic amendments could be a successful technique for stabilization of metals in contaminated soils

Diversidad bacteriana en suelos de zonas contaminadas y no contaminadas de una mina de cobre = Bacterial diversity in soils from contaminated and uncontaminated areas of a copper mine

Para entender la dinámica ecológica del suelo es de primordial importancia realizar un esquema de la distribución filogenética de las distintas bacterias que viven en él. Los análisis moleculares, en especial el metagenómico, puede aportar información detallada sobre la diversidad, estructura y funcionamiento de los microorganismos presentes en un suelo, información que pueden servir como base para su manejo y recuperación. El objetivo de este estudio fue evaluar la diversidad de las comunidades bacterianas en dos zonas de un suelo minero ubicado en la comunidad de Madrid. Los muestreos se realizaron en dos zonas de la mina identificadas como zona 1 (suelo no afectado) y zona 3 (zona de escombrera). Se realizaron análisis metagenómicos de las comunidades bacterianas presentes, con muestras de ambas zonas. Del total de secuencias bacterianas evaluadas, sólo el 1% mostró coincidencias en las bases de datos del Centro Nacional para la Información Biotecnológica (NCBI). Los resultados mostraron que el número de secuencias del dominio Bacteria es mayor en la zona 1 que en la zona 3. Aunque no se encontraron diferencias significativas entre los diferentes filos de bacterias por zona, sí se observaron diferencias en cuanto al número de especies dentro de los diferentes filos y entre las zonas de muestreo

Effects of soluble humic acids on the uptake of heavy metals by Vetiveria zizanioides (L.) Nash in contaminated mining soils

In the past, mining wastes were left wherever they might lie in the surroundings of the mine area. Unfortunately, inactive and abandoned mines continue to pollute our environment, reason why these sites should be restored with minimum impact. Phytoextraction is an environmental-friendly and cost-effective technology less harmful than traditional methods that uses metal hyperaccumulator or at least tolerant plants to extract heavy metals from polluted soils. One disadvantage of hyperaccumulator species is their slow growth rate and low biomass production. Vetiveria zizanioides (L.) Nash, perennial species adapted to Mediterranean climate has a strong root system which can reach up to 3 m deep, is fast growing, and can survive in sites with high metal levels (Chen et al., 2004). Due to the fact that metals in abandoned mine tailings become strongly bonded to soil solids, humic acids used as chelating agents could increase metal bioavailability (Evangelou et al., 2004; Wilde et al., 2005) and thereby promote higher accumulation in the harvestable parts of the plant. The objective of this study was to examine the performance of humic acid assisted phytoextraction using Vetiveria zizanioides (L.) Nash in heavy metals contaminated soils

Use of leonardite humic acids for metals extraction in mine soils

Mine soils usually exhibit high levels of metal contamination. Phytoextraction is an environmental friendly and cost-effective technique for soil remediation, which consists of removal of metals from soil by plant roots and their translocation to aerial parts. Humic substances used as soil amendments could enhance metal mobility and uptake by plants due to formation of soluble complexes. This study aimed to evaluate the effects of a commercial humic acid derived from leonardite added at different rates and pH to a contaminated soil from an abandoned copper mine in Colmenarejo (Madrid, Spain) on metal mobility. The objective was to assess its potential as soil amendment for phytoextraction. Soil samples (10 g) were sequentially extracted 6 times with 20 mL of solution containing humic acid at: 0 (control), 0.25, 1, and 5 g L-1. Solutions were previously adjusted to pH: 4, 6.1 (natural soil pH) and 8. Extracts were analyzed for pH, electrical conductivity, metal concentrations (Cu and Zn) and ratio of absorption at 465 to 665 nm (E4/E6) as an indirect measure of soluble organic matter content. Results showed that addition of higher doses of humic acid increased soluble organic matter content, and therefore extracted a higher concentration of Zn and particularly Cu, due to formation of soluble humic complexes. At higher pH humic acid became more soluble and managed to extract increasing amounts of metals, except in the highest humic acid treatment due to its precipitation or flocculation. The use of this humic acid as soil amendment could promote metal phytoextraction by tolerant plants in contaminated mine soils, but it should be applied at proper pH and other soil conditions to avoid risk of metal leaching to groundwate

Analysis of the performance of a polarized LiDAR imager in fog

This paper focuses on exploring ways to improve the performance of LiDAR imagers through fog. One of the known weaknesses of LiDAR technology is the lack of tolerance to adverse environmental conditions, such as the presence of fog, which hampers the future development of LiDAR in several markets. Within this paper, a LiDAR unit is designed and constructed to be able to apply temporal and polarimetric discrimination for detecting the number of signal photons received with detailed control of its temporal and spatial distribution under co-polarized and cross-polarized configurations. The system is evaluated using different experiments in a macro-scale fog chamber under controlled fog conditions. Using the complete digitization of the acquired signals, we analyze the natural light media response, to see that due to its characteristics it could be directly filtered out. Moreover, we confirm that there exists a polarization memory effect, which, by using a polarimetric cross-configuration detector, allows improvement of object detection in point clouds. These results are useful for applications related to computer vision, in fields like autonomous vehicles or outdoor surveillance where many variable types of environmental conditions may be present.Agència de Gestió d’Ajuts Universitaris i de Recerca (2021FI_B2 00068, 2021FI_B2 00077); DSTL (DSTLX1000145661); Ministerio de Ciencia e Innovación (PDC2021-121038-I00, PID2020-119484RB-I00).Peer ReviewedPostprint (author's final draft

Implantación de metodologías de aprendizaje y evaluación continua en la docencia de la Edafología en el ámbito de la ingeniería agronómica

[SPA] El objetivo fundamental de este trabajo es la evaluación de la implantación de metodologías de enseñanza-aprendizaje en la materia de Edafología en diferentes grados del ámbito agronómico y analizar los resultados académicos obtenidos en cada uno de los grados. El Grupo de Innovación edu-SOIL (UPM) aprovechando los recursos de las TIC, con materiales interactivos de consulta y apoyo de Webquest para elaborar un trabajo de curso, ha establecido un proceso de enseñanza aprendizaje acorde con los sistemas metodológicos previstos en el EEES. Se presentan en el trabajo, además de una breve recopilación de la metodología aplicada, la evolución de las tasas de eficiencia y éxito a lo largo de 2-3 años desde la implantación de los planes de estudio. Se pone de manifiesto la influencia de la estructura de cada plan de estudios en los resultados alcanzados así como la influencia del número de ECTS en la impartición de la materia. [ENG] The main objective of this study was to evaluate the implementation of teaching-learning methodologies in the field of Soil Science in different degrees of the agronomic ambits and to analyze the results obtained in each degree. The edu-SOIL Innovation Group (UPM) taking advantage of TIC resources, using interactive course material and using a Webquest for a class project has established a process of teaching and learning in line with the methodological systems under the European system. This work presents a brief description of the methodology used along with the evolution of efficiency and success rates over 2-3 years since the implementation of the curriculum. The study shows the influence of the structure of each curriculum in the results achieved and also the effect of the number of ECTS in teaching the subject