Permeable reactive barriers for the remediation of groundwater in a mining area: results for a pilot-scale project

The Sierra Minera of Cartagena-La Union is located in the Region of Murcia, Southeast of Spain. This zone presents high levels of heavy metals due to natural, geogenic reasons. In addition, the prolonged mining activity, and subsequent abandonment of farms, has had consequences on the environment, including severe affectation of the groundwater in the area. To remediate this situation, the Permeable Reactive Barrier (PRB) technology was assayed, which required in addition to the hydro-geological study of the zone, a careful optimization study for the design and construction of PRBs. For such a purpose a pilot-scale project was developed, and this communication reports some of the most relevant findings obtained after a four-years monitorization period. The selected reactive material for the PRBs was limestone filler. The filler is a waste material produced in many factories in the zone. These residues have good adsorption properties, high alkalinity, low cost and high availability, which make them suitable for use in remediation. The PRB was constituted by a 50% limestone filler and 50% sand, a proportion optimized by means of independent batch experiments. A layer of gravel was placed at the top, and on it a layer of natural soil. The barrier was designed in the form of a continuous trench, because the level of the contaminated groundwater was not very deep. In this way, the barrier could be prepared with standard excavation equipment. Parallel to the barrier, 6 wells where arranged downstream for sample collection. The pH and conductivity of the samples was measured directly in situ, and the content of Zn, Cd, Cu, Fe, and Pb were analyzed in the laboratory. All the samples collected after the PRB was constructed had basic pH values between 7.5 and 8. The conductivity was between 5 and 11 mS / cm except for the well 4, which had a value of 3.70 mS / cm. The concentration values of trace elements were below the detection limit (atomic absorption measurement) in most of cases, or showed values below normal levels of the area. Our results prove that limestone filler is suitable as the active component of PRBs barriers for sites polluted by trace elements. Following this relatively simple technology, there is no risk for human health or ecosystem, and a big cost-saving can be obtained in projects focused to the remediation of areas affected by mining activities

La mineralogía del suelo como indicador para el análisis de riesgos en zonas críticas mineras abandonadas

Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Uptake of potentially toxic elements by edible plants in experimental mining Technosols: preliminary assessment

A study was carried out to evaluate the absorption of potentially toxic elements from mining Technosols by three types of vegetable plants (broccoli (Brassica oleracea var. italica), lettuce (Lactuca sativa) and onion (Allium cepa)), the different parts of which are intended for human and farm animal consumption (leaves, roots, edible parts). The preliminary results obtained highlight the importance of the design of the mining Technosols used for agricultural purposes, obtained from soils and sediments of mining origin and amended with residues of high calcium carbonate concentrations (limestone filler and construction and demolition wastes). The experiment was carried out in a greenhouse, and the total metal(loid)s concentration (As, Pb, Cd, Cu, Fe, Mn and Zn) of the soil, rhizosphere, aqueous leachates and plant samples was monitored, the translocation and bioconcentration factors (TF and BCF, respectively) being calculated. The characterization of the soils included a mobilization study in media simulating different environmental conditions that can affect these soils and predicting the differences in behavior of each Technosol. The results obtained showed that the levels of potentially toxic elements present in the cultivated species are within the range of values mentioned in the literature when they were cultivated in soils with calcareous amendments. However, when the plants were grown in contaminated soils, the potentially toxic elements levels varied greatly according to the species, being higher in onions than in lettuce. Experiments with the use of lime filler or construction and demolition wastes for soil remediation result in crops that, in principle, do not present health risks and are similar in development to those grown on non-contaminated soil

Assessment of risk from lead intake in mining areas: proposal of indicators

This study discusses an estimate of the risk associated with the intake of soil contaminated by lead, based on the nature of the source, through a detailed study of the parameters that can influence the bioaccessibility of the element from soil intake. Statistical variables that are related to the solubility and bioavailability of lead are used for this purpose. This includes considering the values of pH, electrical conductivity, particle size, mineralogical composition and the bioaccessibility/bioasimilability of lead. Obtaining an algorithm, represented by different probability distributions of the parameters considered, needs a thorough knowledge of the source materials, which may allow estimating/evaluating the intake health risk provided by the concentration of the metal present. The selected materials are from sites affected by mining activities in the Region of Murcia (SE of Spain) and soils in nearby areas, using a total of 186 samples. Soil samples, once screened and homogenized, were parameterized by determining pH, electrical conductivity, granulometry, both total and water-extractable Pb content. Oral bioaccessibility tests were also performed, and a detailed mineralogical analysis by X-ray diffraction was carried out

DataSheet_2_Immunometabolic involvement of hepcidin genes in iron homeostasis, storage, and regulation in gilthead seabream (Sparus aurata).pdf

Iron is essential for all living things, especially marine organisms, due to its low availability in the marine environment. Iron regulation is key in all vertebrates and is controlled by hepcidin–ferroportin. To improve the knowledge of iron homeostasis in fish, an iron overload was induced in gilthead seabream (Sparus aurata), which was chosen as a study species because of its high interest in Mediterranean aquaculture. The amount of iron in different tissues was measured to determine its biodistribution and/or bioaccumulation. Since the liver is directly involved in iron metabolism, the morphological changes induced in this organ as a consequence of the iron increase were studied. The bactericidal activity of fish skin mucus was also determined, observing that it decreased in fish with high iron levels compared to control fish. In addition, to better understand iron regulation, the gene expression of hepcidin, ferroportin, transferrin, and ferritin was evaluated in the head kidney (the main hematopoietic organ in this species) and in the liver. Special interest was taken in the study of the multiple copies of the hamp2 gene present in the gilthead seabream genome. Bioinformatic analysis of the protein sequences derived from these hepcidin genes allowed us to determine the presence of one type I hepcidin and 12 type II hepcidins, all of them with antimicrobial potential. This number of mature hepcidin sequences found in gilthead seabream is the highest within Eupercaria described to date. All the results obtained indicate that the modulation of iron in seabream seems to be much more complicated than in other vertebrates, probably due to the possible involvement of the different hepcidins as mediators between iron metabolism and host immune response.</p

DataSheet_1_Immunometabolic involvement of hepcidin genes in iron homeostasis, storage, and regulation in gilthead seabream (Sparus aurata).pdf

Iron is essential for all living things, especially marine organisms, due to its low availability in the marine environment. Iron regulation is key in all vertebrates and is controlled by hepcidin–ferroportin. To improve the knowledge of iron homeostasis in fish, an iron overload was induced in gilthead seabream (Sparus aurata), which was chosen as a study species because of its high interest in Mediterranean aquaculture. The amount of iron in different tissues was measured to determine its biodistribution and/or bioaccumulation. Since the liver is directly involved in iron metabolism, the morphological changes induced in this organ as a consequence of the iron increase were studied. The bactericidal activity of fish skin mucus was also determined, observing that it decreased in fish with high iron levels compared to control fish. In addition, to better understand iron regulation, the gene expression of hepcidin, ferroportin, transferrin, and ferritin was evaluated in the head kidney (the main hematopoietic organ in this species) and in the liver. Special interest was taken in the study of the multiple copies of the hamp2 gene present in the gilthead seabream genome. Bioinformatic analysis of the protein sequences derived from these hepcidin genes allowed us to determine the presence of one type I hepcidin and 12 type II hepcidins, all of them with antimicrobial potential. This number of mature hepcidin sequences found in gilthead seabream is the highest within Eupercaria described to date. All the results obtained indicate that the modulation of iron in seabream seems to be much more complicated than in other vertebrates, probably due to the possible involvement of the different hepcidins as mediators between iron metabolism and host immune response.</p

New insights into the genetic etiology of Alzheimer’s disease and related dementias

Characterization of the genetic landscape of Alzheimer’s disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/‘proxy’ AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

New insights into the genetic etiology of Alzheimer’s disease and related dementias

Characterization of the genetic landscape of Alzheimer’s disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/‘proxy’ AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele