Human health risks associated with urban soils in mining areas

We thank Ms. I. Martinez Segura and Mr. M.J. Roman Alpiste for their assistance in laboratory work. Additionally, Dr. A. Parviainen acknowledges the `Juan de la Cierva-Incorporaci ' on' fellowship (grant number IJCI-2016-27412); and Dr. J.P. Arrebola acknowledges the Ram ' on y Cajal program (grant number RYC-2016-20155) from the Spanish Ministry of Science, Innovation and Universities. Research performed at the UGR was supported by the Project RTI 2018-094327-B-I00, funded by the Ministry of Science, Innovation and Universities. The European Regional Development Fund (ERFD) and the European Social Fund (ESF) of the European Commission (co)funded the fellowships, research and infrastructure endeavors involved in this research performed at the Instituto Andaluz de Ciencias de la Tierra (UGR-CSIC).We studied the chemical composition of As and Pb in total (<2 mm) and fine fractions (<50 μm) of 52 urban soil samples from Minas de Riotinto (mining area) and Aracena (non-exposed area) in SW Spain. In addition to a soil phytotoxicity bioassay using Lactuca Sativa L., we modelled and performed carcinogenic and non-carcinogenic human health risk assessment, later comparing our data with relative cancer mortality rates reported at the municipal level. This study demonstrates that mineralized bedrock and natural soil-forming processes affect the geochemistry of natural (in-situ) urban soils, which in many cases surpass the regulatory levels for As (36 mg/kg) and Pb (275 mg/kg). Fine fractions of in-situ and mixed urban soils —susceptible of inhalation— are significantly enriched in As and Pb with respect to fine fractions of aggregate materials (ex-situ soils of chalky sands and gravel) in Minas de Riotinto. The soils in Minas de Riotinto are significantly enriched in As (total and fine fractions) and Pb (total fraction) with respect to Aracena. Despite elevated bulk concentrations of As and Pb, only one in-situ sample exhibits phytotoxic effects of the soil-water extracts on Lactuca Sativa L. seeds. Health risk assessment of these towns as exposure areas indicates that the soils of Minas de Riotinto are indeed a health risk to the residents, whereas there is no potential risk in Aracena. The reported relative mortality rates in Minas de Riotinto show a greater mortality of carcinogenic tumors potentially related to As and Pb exposure, including lung cancer. Both soil type and use must be considered when administrators or policy-makers evaluate health risks involved in urbanistic decision-making. To minimize exposure risk and adverse health outcomes, we recommend that insitu soils surpassing regulatory levels for As and Pb in public playgrounds and passing areas should be covered with aggregate materials.'Juan de la Cierva-Incorporacion' fellowship IJCI-2016-27412Spanish Government RYC-2016-20155Ministry of Science, Innovation and Universities RTI 2018-094327-B-I00European Regional Development Fund (ERFD) of the European Commission European Social Fund (ESF) of the European Commissio

Application of biochar for the restoration of metal(loid)s contaminated soils

Biochar has recently aroused great interest for the restoration of contaminated soils since it improves soil properties and induces the immobilization of pollutants. This study evaluates the use of biochar from plant pruning, applied as an amendment, for immobilizing metal(loid)s in a highly contaminated soil as well as for reducing the phytotoxicity of these pollutants by promoting natural revegetation. For this purpose, a bioassay with Trifolium pratense L. was used to test the effectiveness of the soil amendment in greenhouse conditions. Three treatments were carried out including soil contaminated with metal(loid)s (RA), and this soil was amended with biochar at different dosage: 4% (RA4B) and 8% (RA8B). A non-contaminated soil (NC) from a nearby area not affected by contamination was used as a control. The results show that biochar increased soil pH by several units depending on the dose used, 8% being the most effective one. Biochar treatments also reduced soluble and bioavailable forms of Zn and Cu. Likewise, phytotoxicity was significantly reduced, promoting seed germination and biomass with plant growth values similar to the nonpolluted soil. In light of the results obtained, the evaluation of the bioremediation potential of biochar under field conditions can be considere

Effect of parent material and atmospheric deposition on the potential pollution of urban soils close to mining areas

A. Vázquez-Arias was awarded a grant by the Spanish Ministry of Science, Innovation and Universities within the Programa de Formación de Profesorado Universitario (FPU19/01989). Dr. A. Parviainen's fellowship ‘Juan de la Cierva –Incorporación’ (IJCI-2016-27412) was funded by the Spanish Ministry of Science, Innovation and Universities. The research performed at the UGR was also supported by the Research Project RTI 2018-094327-B-I00 (Ministry of Science, Innovation and Universities). Fellowships, research, and infrastructure grants supporting this research performed at the Instituto Andaluz de Ciencias de la Tierra (UGR-CSIC) have been (co)funded by the European Regional Development Fund (ERFD) and the European Social Fund (ESF) of the European CommissionThe aim of this study is to analyse the concentration and determine the sources of potentially toxic elements (PTEs) in urban soils under the influence of mining activities. To this end, topsoil samples were collected in the public parks and green areas in Minas de Riotinto (a town next to one of the largest open pit mines in the world) and Aracena (a nearby town outside the area of influence of the mine). After determining the concentrations of elements of interest single bondCr, Co, Ni, Cu, Zn, As, and Pb— the values were compared in terms of the soil location and origin (in-situ or ex-situ), and with the background and regulatory levels for the region. The elemental concentrations in the fine fraction of the soils (particles <50 μm) were also measured. The concentrations of some PTEs (Cu, As and Pb), also found in the dust from nearby mines, were higher in the in-situ soils of Minas de Riotinto than in those of Aracena. The concentrations of PTEs in ex-situ soils of both towns were much lower than in in-situ soils, and similar between the two locations, revealing the influence of the parent material as a primary source of PTEs. However, the concentrations of As and Cu in the ex-situ soils of Minas de Riotinto were significantly higher than in those of Aracena, while a significant increase of these elements in the fine fraction was seen for both in-situ and ex-situ soils. These two elements are directly related to mining activity, implying that atmospheric deposition of dust from the mines contributes to the greater concentration of PTEs in the soils of Minas de Riotinto. Because these sources lead to soils with potentially dangerous concentrations of pollutants, they should be further studied in relation to their long-term influence on human healthS

Application of Biochar for the Restoration of Metal(loid)s Contaminated Soils

Funding: The work has been supported by funds from the Spanish Ministry of Economy, Industry and Competitiveness through the Project “CTM2017-86504-R”, and by Ministry of Science, Innovation and Universitiesam trought Research Project “RTI2018-094327-B-I00”.Biochar has recently aroused great interest for the restoration of contaminated soils since it improves soil properties and induces the immobilization of pollutants. This study evaluates the use of biochar from plant pruning, applied as an amendment, for immobilizing metal(loid)s in a highly contaminated soil as well as for reducing the phytotoxicity of these pollutants by promoting natural revegetation. For this purpose, a bioassay with Trifolium pratense L. was used to test the effectiveness of the soil amendment in greenhouse conditions. Three treatments were carried out including soil contaminated with metal(loid)s (RA), and this soil was amended with biochar at different dosage: 4% (RA4B) and 8% (RA8B). A non-contaminated soil (NC) from a nearby area not affected by contamination was used as a control. The results show that biochar increased soil pH by several units depending on the dose used, 8% being the most effective one. Biochar treatments also reduced soluble and bioavailable forms of Zn and Cu. Likewise, phytotoxicity was significantly reduced, promoting seed germination and biomass with plant growth values similar to the non-polluted soil. In light of the results obtained, the evaluation of the bioremediation potential of biochar under field conditions can be considered.Ministry of Science, Innovation and Universitiesam trought Research Project RTI2018-094327-B-I00Ministerio de Economía, Industria y Competitividad, Gobierno de España CTM2017-86504-

Gypsum mining spoil improves plant emergence and growth in soils polluted with potentially harmful elements

Purpose Soil pollution is a major problem worldwide. Some anthropogenic activities, such as mining, may exceed soil capacity, causing relevant health and ecosystem hazards. The use of mineral amendments can help reduce soil pollution. Gypsum mining spoil (GS) is a waste material highly produced in gypsum mining industry, which has never been used in soil remediation despite its high potential as amendment of polluted soils. In this study, we carried out an ex-situ experiment to assess for the first time the capacity of GS to both reduce the availability of Potentially Harmful Elements (PHEs) in soils and promote seed emergence. Methods Soils affected by residual pollution after the Aznalcóllar mine spill were collected, treated with GS in three different proportions, and sown with seeds of two non-genetically related species. Seed emergence and biomass production were monitored, and PHE content in soils and plants were analysed. Results We have observed a direct and very positive relation between GS and both the reduction of PHE availability and PHE uptake by plants, and the increase of plant emergence and growth, especially with the addition of the highest doses of the amendment. Conclusion This study highlights the promising results of GS as a novel soil amendment to be used in the remediation of polluted soils and vegetation recovery. Moreover, using GS as soil amendment will bring the opportunity to sustainably manage this waste material and reduce its social and environmental impact parallelly to the mitigation of PHE hazards.KNAUF-GmbHMinistry of Science, Innovation and Universities RTI 2018-094327-B-I00Tatiana-Perez-de-Guzman-el-Bueno Foundation PhD grant Programme 201

Mineralogical association and geochemistry of potentially toxic elements in urban soils under the influence of mining

Polluted soil is an important source of exposure to potentially toxic elements (PTEs) for humans, especially in urban areas. We studied the fate of PTEs in the total (<2 mm) and fine (<50 μm) fractions of urban soils in playgrounds, passing areas, and vacant lots of the historic mining village of Minas de Riotinto in SW Spain. The mineralogical and chemical observations included analysis by scanning electron microscopy, electron backscatter diffraction, X-ray diffraction, chemical analysis of Al, V, Cr, Mn, Co, Ni, Cu, Zn, Rb, Sr, As, Cd, Ba, Tl, and Pb after acid digestion by Inductively Coupled Plasma-Mass Spectrometry and Sb by X-ray fluorescence. The total and fine fractions of natural and mixed (consisting of natural soils and aggregate pavements) urban soils have significantly higher concentrations of sulfide-associated PTEs (Ni, Cu, Zn, As, Sb, and Pb) and Ba in comparison to the aggregate pavements. Most of the natural and mixed urban soils surpass the regulatory levels set by the regional Government for As and Pb to declare a soil as contaminated. This work highlights the mineralogical source of PTEs in the urban soils. Primary geogenic sulfide minerals are prone to oxidation promoting dissolution of PTEs and acid generation in the future. Additionally, for the first time, we have described arsenian plumbojarosite and beudantite in urban soils which are abundant secondary phases under the circumneutral pH conditions, effectively retaining As and Pb. Inhalable small PTE-rich particles (<10 μm) are present in many soils in playgrounds and garden areas potentially posing health risk to residents upon dusting and resuspension in the air

Effect of parent material and atmospheric deposition on the potential pollution of urban soils close to mining areas

The aim of this study is to analyse the concentration and determine the sources of potentially toxic elements (PTEs) in urban soils under the influence of mining activities. To this end, topsoil samples were collected in the public parks and green areas in Minas de Riotinto (a town next to one of the largest open pit mines in the world) and Aracena (a nearby town outside the area of influence of the mine). After determining the concentrations of elements of interest –Cr, Co, Ni, Cu, Zn, As, and Pb— the values were compared in terms of the soil location and origin (in-situ or ex-situ), and with the background and regulatory levels for the region. The elemental concentrations in the fine fraction of the soils (particles <50 μm) were also measured. The concentrations of some PTEs (Cu, As and Pb), also found in the dust from nearby mines, were higher in the in-situ soils of Minas de Riotinto than in those of Aracena. The concentrations of PTEs in ex-situ soils of both towns were much lower than in in-situ soils, and similar between the two locations, revealing the influence of the parent material as a primary source of PTEs. However, the concentrations of As and Cu in the ex-situ soils of Minas de Riotinto were significantly higher than in those of Aracena, while a significant increase of these elements in the fine fraction was seen for both insitu and ex-situ soils. These two elements are directly related to mining activity, implying that atmospheric deposition of dust from the mines contributes to the greater concentration of PTEs in the soils of Minas de Riotinto. Because these sources lead to soils with potentially dangerous concentrations of pollutants, they should be further studied in relation to their long-term influence on human health.Spanish Government IJCI-2016-27412 RTI 2018-094327-B-I00Ministry of Science, Innovation and Universities - European Regional Development Fund (ERFD)European Social Fund (ESF) of the European Commission European Commission FPU19/0198

Validation of a new portable metabolic system during an incremental running test

We tested a new portable metabolic system, the Jaeger Oxycon Mobile (OM) at a range of running speeds. Six subjects carried out, in random order, two incremental tests on a treadmill, one of them using the OM, and the other using the Jaeger Oxycon Pro (OP). There are systematic errors in the measurements of oxygen consumption (VO2) and respiratory exchange ratio (RER) with the OM. Production of CO2 (VCO2) tends to be overestimated by the OM, although the differences are not significant. Ventilation (VE) showed very similar values in both analyzers. Data of VO2 and RER were corrected with a regression equation which minimised the differences among the devices. The portable metabolic system OM makes systematic errors in measurements of VO2 and RER which can be adjusted with a regression analysis to obtain data comparable to those obtained by fixed system

Evolution of the Residual Pollution in Soils after Bioremediation Treatments

This study is focused on one of the most important spills that ever happened in Europe, the Aznalcóllar’s mine spill. The extensive application of phytostabilization in the area led to the implementation of the Guadiamar Green Corridor (GGC). Soil physicochemical properties were analyzed and the total concentration of Pb, As, Zn and Cu was measured by X-ray fluorescence (XRF); bioassay using Lactuca sativa L. was applied to assess potential toxicity. Two decades after the accident, some soils affected by residual contamination continue to appear in the area. According to regulatory levels, Pb and As concentrations are exceeded in around 13%and 70%, respectively, in the uppermost part of the soils (first 10 cm). The change in soil properties after bioremediation treatment positively promoted the reduction in the potential mobility of pollutants by the increase in pH, CaCO3 content and organic carbon. Anyway, the bioassay with Lactuca sativa, indicated that around 25% of the soils showed toxicity by the reduction of the root elongation in relation to the control samples. Our results indicate that monitoring of the GGC is still needed, together with the application of soil recovery measures to reduce the potential toxicity in some sectors of the affected area.This research was funded by the Research Project RTI 2018-094327-B-I00 (Ministry of Science, Innovation and Universities) and the Research Groups RNM-269 and RNM-101 (Junta de Andalucía, Spain)

Human health risks associated with urban soils in mining areas

samples from Minas de Riotinto (mining area) and Aracena (non-exposed area) in SW Spain. In addition to a soil phytotoxicity bioassay using Lactuca Sativa L., we modelled and performed carcinogenic and non-carcinogenic human health risk assessment, later comparing our data with relative cancer mortality rates reported at the municipal level. This study demonstrates that mineralized bedrock and natural soil-forming processes affect the geochemistry of natural (in-situ) urban soils, which in many cases surpass the regulatory levels for As (36 mg/kg) and Pb (275 mg/kg). Fine fractions of in-situ and mixed urban soils —susceptible of inhalation— are significantly enriched in As and Pb with respect to fine fractions of aggregate materials (ex-situ soils of chalky sands and gravel) in Minas de Riotinto. The soils in Minas de Riotinto are significantly enriched in As (total and fine fractions) and Pb (total fraction) with respect to Aracena. Despite elevated bulk concentrations of As and Pb, only one in-situ sample exhibits phytotoxic effects of the soil-water extracts on Lactuca Sativa L. seeds. Health risk assessment of these towns as exposure areas indicates that the soils of Minas de Riotinto are indeed a health risk to the residents, whereas there is no potential risk in Aracena. The reported relative mortality rates in Minas de Riotinto show a greater mortality of carcinogenic tumors potentially related to As and Pb exposure, including lung cancer. Both soil type and use must be considered when administrators or policy-makers evaluate health risks involved in urbanistic decision-making. To minimize exposure risk and adverse health outcomes, we recommend that insitu soils surpassing regulatory levels for As and Pb in public playgrounds and passing areas should be covered with aggregate materials