SSS7.6

The spatial variability of hydrocarbon content and the physical and chemical properties of the soil were assessed by combining traditional soil sampling and proximal geophysical survey with the aim of planning a pilot phytoremediation experiment in an agricultural area west of Milan (Lombardy, Italy).

The area, an irrigated arable land of about 1 ha, was affected by a refined oil spillage from an underground pipeline in 2015. Contamination surveys were carried out with a continuous core drilling technique using an hydraulic probe (131 cm diameter core). Heavy (C>12) and light (C<12) alkanes and aromatic compounds (benzene, ethylbenzene, styrene, toluene and xilenes) were measured up to three meters depth. Results showed a predominance of heavy hydrocarbons (C>12) with respect to light hydrocarbons (C<12) and aromatic compounds. A map of heavy hydrocarbons soil concentration was obtained using geostatistical techniques.

In 2019 it was decided to carry out a phytoremediation intervention to reclaim the first meter of contaminated soil where heavy hydrocarbons content ranges from 500 to 5000 mg/kg. The first step of the intervention consists in cultivating a wide variety of vegetal species in experimental plots with different pollution to verify their effectiveness for remediation in the specific environmental condition of that area. For the reclamation of deeper more contaminated layers, enhanced bioremediation have been planned to be used.

Soil properties, which are crucial for planning phytoremediation activities, were investigated using traditional methods and geophysical surveys. Traditional soil survey was performed describing the 23 drilling cores used to monitor pollutants and opening five profiles; the samples were collected from genetic soil horizons and analysed for organic carbon and the main nutrient (nitrogen, phosphorus and potassium) content, total carbonates, texture and pH in water. The distribution of Eutric Luvisols and Cambisols, developed mainly on sandy or sandy skeletal substrate, was represented in a soil map. A proximal geophysical survey was carried out using an electromagnetic induction (EMI) sensor (GSSI Profiler EMP-400) by acquiring multiple frequencies; soil detailed conductivity maps for each frequency (15000, 9000 and 2000 kHz) were obtained. No significant relationships were found between soil electrical conductivity and hydrocarbon concentration, whereas there are relationships with the main soil characteristics: this allowed detailed maps of soil parameters to be obtained.

On the base of both the soil spatial characterization (traditional soil map and detailed soil property maps with geophysical approach) and the contaminant distribution (hydrocarbon map distribution using geostatistical approach), homogeneous areas were identified in which to set up experimental phytoremediation plots to test the most suitable species for reclamation, chosen among the most widespread crops in the region and considering their suitability for biomass and bio-oil production.

How to cite: Ferré, C., Casati, E., Cerutti, G., Gentili, R., Francioli, A., and Comolli, R.: Combining traditional and geophysical soil investigation for phytoremediation planning in a hydrocarbon polluted area, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10808, https://doi.org/10.5194/egusphere-egu21-10808, 2021.

Outdoor shooting ranges provide recreational facilities for millions of people in the world. However, there are many negative effects on the environment and public health arising from this activity.

In particular, potential risks are mostly associated with the residential or agricultural use of decommissioned outdoor ranges, where bullets and targets have been deposited during the shooting activity.

This is the case of an outdoor shooting range in Campania region (Southern Italy), located in an area of historical and naturalistic value, close to the ancient Etruscan village of Suessola (VII century b.C.). Specifically, the study site is located within an agricultural land declared unsuitable for agricultural and forest-pastoral production by the Italian Ministry of Agricultural, Food and Forestry Resources, due to an extensive long term soil contamination associated with Pb, Sb, PAHs, dioxins, PCBs and C> 12 hydrocarbons.

With the purpose of planning a detailed site characterization of the shooting range area, a preliminary environmental survey was carried out by means of field investigations (ultrasonic penetrometry, electromagnetic induction - EMI -  and gamma spectroscopy) and geochemical prospecting.

Cone index data, obtained by ultrasonic penetrometer measurements, indicated the presence of a very dense, hard and impenetrable to hand hauger layer, recognised as travertine rock, from 25 to more than 55 cm of depth, and dipping northward.

Continuous EMI data and gamma spectroscopy (K %, eU ppm, eTh ppm) parameters were acquired in the field in order to identify homogeneous zones in which further geochemical investigations should have been focused. In fact, apparent electrical conductivity (ECa) map, consistently with the gamma ray dose rate distribution map, allowed to highlight three separated singularity areas  N-S oriented.

XRF analyses, carried out through a portable analyzer on soil samples collected along soil profiles digged from topsoil until the travertine layer, showed a high contamination by Pb (greater than 1000 mg/kg) and Sb (greater than 30 mg/kg) in the first 15 cm of depth, at a distance of approximately 90 m from the shooting lanes.

Chemical analyses were also performed on 32 topsoil samples collected on the basis of a regular grid across the study area. Concentrations of 13 PAHs compounds were determined and the highest values were found close to the firing lanes where in soil a huge amount of shooting target fragments are present.

The preliminary results showed how the contamination due to the previous activity in the area produced a spatial distribution of contaminats differentiated on the basis of their source material and their role in the shooting process.

How to cite: Albanese, S., Guarino, A., Aruta, A., Roberto, D. M., Carlo, P., Massimo, F., and Simona, V.: Soil pollution in a decommissioned shooting range: a preliminary survey of the spatial variability of legacy pollutants., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4969, https://doi.org/10.5194/egusphere-egu21-4969, 2021.

Lead is one of the extensively distributed PTEs (potentially toxic elements) in the environment due to wide-scale anthropogenic activities (e.g., mining, vehicular emissions, industries, etc.), its geochemical feature, and natural abundance. The World Health Organization (WHO) defined Pb as 2^nd most dangerous element for health, with particular concern for mental and physical disorders in adults and children. Salgótarján and Ózd cities (Northern Hungary) are two main former heavy industrial cities, with the smelter, steel industry, coal-fired power plant, coal mines, etc., supplied the country with coal and iron and steel products for centuries. The main aim of the research is to obtain a lead distribution map of the region and identify the potential sources by use of stable lead isotopes.

Urban soil samples were collected from each km² of both cities. Additionally, a soil as geochemical background, as well as local slag and coal as suspected major pollution sources were collected. Lead content and stable Pb isotopes of all samples were analyzed by ICP-MS spectrometry.

Obtained results indicate heterogeneous distribution and high lead enrichment in both cities, where the Pb concentration ranged from 8.5 to 1692 ppm in Salgótarján and from 6.6 to 1674 ppm in Ózd. The average lead isotopic ratio in soil samples ranged from 1.146 to 1.240 (²⁰⁶Pb/²⁰⁷Pb) for Salgótarján and from 1.084 to 1.240 for Ózd. Total Pb concentration and isotopic ratios of slag and coal samples depicted notable differences as isotopic ratios for Salgótarján and Ózd coals are ²⁰⁶Pb/²⁰⁷Pb:1.175 and ²⁰⁶Pb/²⁰⁷Pb:1.256, respectively. Meanwhile, the lead content in the Salgótarján fly-ash slag (from the coal-fired power plant) was identified as 14 ppm (²⁰⁶Pb/²⁰⁷Pb:1.175, similar to coal). However, the Ózd smelter slag was characterized by high lead concentration (202 ppm) and lowest isotopic composition (²⁰⁶Pb/²⁰⁷Pb=1.118).

To calculate the relative contribution of anthropogenic sources, suggested binary mixing models were used. It is revealed that in Salgótarján soils average 34 % of Pb enters from industrial sources, 43 % from coal, and 23 % from the natural environment. In contrast, in Ózd, the proportion of anthropogenic lead is estimated on average by 53 % from industries (slag), 38 % from coal, and only 9% from natural input. The proportion of coal and slag in the soil samples was proved by thorough microscopy observations and SEM analysis as well.

In conclusion, based on the comprehensive analysis, local smelter and steel-iron industries were the dominant Pb contamination sources in both cities.

Keywords: Lead pollution, isotopic ratio, source identification, binary mixing model

How to cite: Abbaszade, G., Tserendorj, D., Salazar, N., Zacháry, D., Völgyesi, P., and Szabó, C.: Long-term lead contamination and isotopic source identification in Northern Hungary, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16066, https://doi.org/10.5194/egusphere-egu21-16066, 2021.

Iron and steel works activities are an important industrial source of pollutants that change soil composition with a wide range of substances containing heavy metals. Determination of the multi-element composition of urban soil contributes to an accurate assessment of the quality of the urban environment. Therefore, concentrations of 15 metals (Ti, V, Cr, Mn, Fe, Co, Ni Cu, Zn, Mo, Ag, Sn, Sb, Pb and W) were measured in Ózd, a former industrial city located at the northern part of Hungary. It has been exposed to contaminants for almost two centuries by different anthropogenic activities such as transportation, coal mining, iron and steel works. In this study, 56 urban soil samples were collected from playgrounds, kindergartens, parks and roadsides, as well as 1 local coal, 1smelter slag and 2 steel slags samples.

In this study, we determined cluster distribution of the samples using compositional data analysis clr-transformed (clr-biplot), k-means cluster analysis (CA) and calculates enrichment factors (EF). To observe the relationships among the 15 metals, the clr-biplot was performed in CoDaPack software and k-means in R statistics, following recommendation in the literature [1].  The results of k-means were overlapped on the clr-biplot and plot on a map. Enrichment factors were calculated for every cluster with the formula: EF=[M/Fe]sample/[M/Fe] background, where (M) metals concentration and Fe was used for normalization. Background values were taken from brown forest soil.

The average concentration of 15 elements in (mg kg^-1) for the 57 samples are Fe(27204), Mn(842), Zn(225), Ti (135),  Pb (81), Cr(41,3), Cu(30.2), V(24.2), Ni(21), Co(7.34), Sn(4.22), Sb(1.41), Mo(1.19), W(0.726) and Ag (0.268), respectively.

The optimal number of clusters are 4, where the most samples in the first cluster are distributed on the northwest side of the city where agricultural activity is a common occasion. Samples forming the second cluster are characteristic in the area of the former iron and steel factory. Samples of the third cluster are located at the new industrial park (northeast side of the city). The fourth cluster samples are derived from the surrounding area the new industrial area and covers most of the city south side. The results of average enrichment factor (EF)>5, which represent significant or very significant enrichment are 1^stcluster Ti, 2^ndcluster W>Ti>Sn>Ag>Cr>Pb>Sb>Zn>Cu, 3^rdcluster W>Cr>Ti, and 4^thcluster Ti>W.

The differences between cluster distributions and enrichment of each metallic element show complexity of the study area, which suggested areas with features associations of elements to natural sources, hybrid (natural and anthropogenic) and industrial areas.

How to cite: Salazar, N., Abbaszade, G., Tserendorj, D., Völgyesi, P., Zacháry, D., Szabó, K., and Szabó, C.: Contamination assessment of heavy metals in urban soil of former industrial city (Ózd, Hungary), EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16203, https://doi.org/10.5194/egusphere-egu21-16203, 2021.

Organochlorine pesticides (OCPs) are a group of synthetic molecules, consisting of organic structures containing at least one aromatic ring and one covalently bound chlorine atom, widely used for decades in agriculture (as insecticides and fungicides) and, subordinately, in the medical field.

The study area, corresponding to the Acerra-Marigliano conurbation, is located in the middle sector of the Campania Plain, a wide coastal belt roughly extending from the Garigliano River plain, in the northwest of the Campania region, to the Sarno River basin, southward of the volcanic complex of Mt. Somma-Vesuvius. Most of the study area is occupied by agricultural activities (crops, orchards and vineyard) and, subordinately, by industrial settlements and urbanized areas. A total of 33 surficial composite soil samples were collected across the study area, with an average density of 1 sample per 4 sqkm, to be analyzed for their OCPs content.

Compared to other synthetic organic pesticides, OCPs show greater environmental persistence and are generally characterized by a marked tendency towards bioaccumulation and biomagnification along trophic chains due to their lipophilic character. The covalent bond between carbon and chlorine in OCP molecules is very stable and resistant to microbial degradation, but some organisms and plants, together with some physical factors (including pH, solar radiation and humidity), can encourage their metabolic degradation.

The best-known OCP is certainly the dichloro-diphenyl-trichloroethane (DDT), which is one the OCPs defined as Persistent Organic Pollutants by the Stockholm Convention (2001), synthesized since 1873 and used as an insecticide and pesticide since the 1940s. DDT has been, and still is, used to combat malaria in some sensitive areas, such as Africa, India and South America, but its use has been banned in Italy since 1978. DDT can undergo degradation processes, including volatilization or photolysis, whose products are dichloro-diphenyl-dichloroethane and dichloro-diphenyl-dichloroethylene (DDD and DDE, respectively), two compounds with similar properties and, above all, highly persistent. The USEPA (2015) has classified DDT and its metabolites as probably carcinogenic substances for humans, also responsible for damage to the liver, reproductive system and nervous system.

This study aimed at investigating the local distribution, possible sources and contamination levels of DDT isomers and metabolites in the soils of the study area. In particular, we considered six compounds: p,p′-DDT; o,p′-DDT; p,p′-DDD; o,p′-DDD; p,p′-DDE and o,p′-DDE. Concentration of ΣDDTs (i.e. the sum of the six compounds) ranges from a minimum of 4.13 ng/g to a maximum of 734.75 ng/g.

The Italian decree 46/2019 establishes a guideline value for DDE, DDD and DDT concentrations in agricultural soils of 10 ng/g. This value is largely exceeded in the whole study area as regards p,p′-DDT and p,p′-DDE, for which the average concentration resulted equal to 70.37 ng/g and 75.94 ng/g, respectively.

O,p′-DDD and o,p′-DDE show very low concentrations throughout the study area with average concentrations of 1.44 ng/g and 0.75 ng/g, respectively; o,p′-DDT (mean = 5.67 ng/g) and p,p′-DDD (mean = 6.24 ng/g) overcome the guideline mostly in soils collected in the surrounding areas of the towns of Acerra, Brusciano and Marigliano.

How to cite: Guarino, A., Aruta, A., Ebrahimi, P., Dominech, S., Lima, A., De Vivo, B., Qi, S., and Albanese, S.: Organochlorine pesticides in the soils of the Acerra plain: concentration and distribution of DDT isomers and metabolites, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5739, https://doi.org/10.5194/egusphere-egu21-5739, 2021.

Reducing health risks has been a concern for decades due to anthropogenic activities, especially agricultural, industrial, and landfills. Hazardous pollution can spread to the environment by various routes (surface soil, raw water, groundwater, etc.). However, the behavior of natural elements needs to be concerned in terms of potential sources of pollution, and many countries face high levels of heavy metal problems in surface soils and groundwater. This study focuses on both anthropogenic activity and the presence of natural heavy metals to investigate the actual sources of pollution within the site. The landfill is located at Chachonsao, Thailand, where industrial waste such as industrial dust, sludge, and cement has accumulated, and surface soil and shallow groundwater sample analysis shows that most soil samples have high concentrations of arsenic that exceed global healthy soil standards (30 mg/kg). And shallow groundwater samples have been shown to contain high concentrations of arsenic that exceed the WHO global drinking water standard (0.01 mg/L). High levels of arsenic in surface soils can be interpreted as not only in the area of ​​the site but also in the surroundings where this contaminated situation can be interpreted as being caused by the presence of natural heavy metals. Thus, we investigated and analyzed further details at this site to clarify the risk level of heavy metals and also the effect of the natural source of arsenic.

How to cite: Pongritsakda, T., Sirivithayapakorn, S., Shiratori, T., and Komai, T.: Analysis of potential sources with heavy metals in a landfill site using preliminary data, A case study in Thailand, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10599, https://doi.org/10.5194/egusphere-egu21-10599, 2021.

The transport phenomenon of pollutants in soil is complicated because of the formation of the flow path in soil. In this study, the relationship between the flow path in the soil and the elution behavior of various components was evaluated by the column tests with different filling methods to change the flow path in the column. The flow path in the column was visualized by using potassium iodide aqueous solution and X-ray CT. Our result shows that the elution behavior of the easily eluted components was not significantly affected by the flow path in the column. In addition, the cation more eluted when the flow path spread throughout the column than when the flow path was intensive. This suggests that eluted components may be affected by anions in soil. From these results, it was found that the elution behavior of components is influenced by the flow path in the column and some were not, and when it was influenced, the degree of influence is different depending on the components.

How to cite: Tsuchida, K., Nakamura, K., Kondo, M., Watanabe, N., and Komai, T.: Relationship between the formation of flow paths and elution behavior with water flow through the soil column, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13731, https://doi.org/10.5194/egusphere-egu21-13731, 2021.

High levels of arsenic in drinking water and food materials continue to pose a global health challenge. Over 127 million people alone in Bangladesh (BD) and West Bengal (WB) state of India are exposed to elevated levels of arsenic in drinking water. Despite decades of research and outreach, arsenic awareness in communities continues to be low. Specifically, very few studies have reported arsenic awareness among low-income farming communities. A comprehensive approach to assess arsenic awareness, hence, is a key step in identifying research and development priorities so that appropriate stakeholder engagement may be designed to tackle arsenic menace. In this study, we developed a 12-point comprehensive arsenic awareness index (CAAI) and identified key awareness drivers (KADs) associated with CAAI using hybrid feature selection for analysing the responses from the survey conducted in arsenic-affected areas of WB and BD. The two questionnaire surveys comprised of 73 questions each, covering the health, water and community, and food related aspect of arsenic contamination. Comparison of CAAIs showed that the BD farmers were generally more arsenic-aware (CAAI = 7.7) than WB farmers (CAAI = 6.8). Interestingly, the reverse was true for the awareness linked to arsenic in the food chain. Application of hybrid feature selection identified 15 KADs, which included factors related to stakeholder interventions and cropping practices. Inclusion of Boruta wrapper in the hybrid feature selection aided in discarding the randomly associated chi-square (χ²) significant variables (p < 0.05), which included the commonly perceived socio-economic factors such as age, gender and income. An inter-comparison of KADs revealed the differences in objectives and importance laid on various interventions under different government regimes for tackling arsenic menace. Hence, the CAAI and KADs combination revealed a contrasting arsenic awareness between the two farming communities, albeit their cultural similarities. For analysing the predictive power of the KADs for CAAI, both linear and non-linear machine learning models were deployed. Among ML algorithms, classification and regression trees and single C5.0 tree could estimate CAAIs with an average accuracy of 84%. Both communities agreed on policy changes on water testing and clean water supply, while there was less importance laid by both farming communities in testing food for arsenic concentration. Specifically, our study shows the need for increasing awareness of risks through the food chain in BD, whereas awareness campaigns should be strengthened to raise overall awareness in WB possibly through media channels as deemed effective in BD. Overall, this study addresses the UN sustainable development goals (SDGs) such as clean water and sanitation (SDG6), zero hunger (SDG2), good health and well-being (SDG3), and echoes with the WHO’s comprehensive action plan of involving water testing, awareness-building campaigns, and mitigation options to combat arsenic toxicity menace. 

How to cite: Mishra, D., Das, B. S., and Menon, M.: Hybrid feature selection and machine learning approaches for assessing the arsenic awareness of local farming communities in Bengal Basin, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2485, https://doi.org/10.5194/egusphere-egu21-2485, 2021.

Trace elements are toxic at high concentrations and present long-term persistency in the environment. Biochar, the solid carbonaceous residue produced by pyrolysis of biomass, has been proven to have great potential to adsorb trace elements [1]. Biochar efficiency for trace element adsorption depends on biochar properties, which are affected by feedstock and pyrolysis conditions [2, 3]. Nevertheless, the effect of biochar ageing on trace element immobilization is still not well understood. To fill this gap, a 2-years field experiment was performed next to the Guadiamar River (SW Spain), which was polluted in 1998 due to the breakage of a mining waste pond, causing the dumping of millions of tonnes of toxic sludge. Consequently, the soils studied have acid pH and high concentrations of trace elements (As, Ba, Cu, Pb and Zn). For this experiment, the soils were amended with 8 t ha^-1 of rice husk and olive pit biochars. Additionally, biochars produced from rice husk, olive pit and wood chips were buried in these polluted soils using permeable bags. After 2 years, soil and biochar properties as well as trace element contents (total and extractable) were determined. The ageing process reduced the aryl C signal in biochar samples as revealed by cross polarization magic angle spinning ¹³C nuclear magnetic resonance (CPMAS NMR) analysis. O-containing groups in aged biochar were detected by Fourier Transform mid-Infrared Spectroscopy (FT-IR). Although biochars effectively adsorbed trace elements from the polluted soils, the contents of CaCl₂-extracted trace elements in the soils were not modified. This is probably due to the extremely high total abundance of trace elements in these soils, which permit a quick remobilization of bound metals refilling of the extractable pool, and replacing the heavy metals adsorbed by biochar. Consequently, the content of extractable trace elements in these polluted soils may only be reduced by a periodic application of high amounts of biochars.

References:

[1] Amin, M.T., Alazba, A.A., Shafiq, M., 2018. Chem. Eng. J. Arab. J. Sci. Eng. 43, 5711-5722.

[2] Campos, P., De la Rosa, J.M., 2020. Sustainability 12, 6025.

[3] Campos, P., Miller, A.Z., Knicker, H., Costa-Pereira, M.F., Merino, A., De la Rosa, J.M., 2020. Waste Manag. 105, 256-267.

Acknowledgements: The former Spanish Ministry of Economy, Industry and Competitiveness (MINEICO), AEI/FEDER and CSIC are thanked for funding the project CGL2016-76498-R. J.M. De la Rosa acknowledges MINEICO for funding his “Ramón y Cajal” contract. P. Campos thanks “Fundación Tatiana Pérez de Guzmán el Bueno” for funding her PhD.

How to cite: De la Rosa, J. M., Campos, P., Miller, A. Z., Velasco-Molina, M., Sánchez-Martín, Á., De la Rosa, A., and Knicker, H.: Effects of biochar ageing on the remediation potential of trace-element polluted soils, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-602, https://doi.org/10.5194/egusphere-egu21-602, 2021.

Salinization is one of the major causes of soil degradation and salt-affected soils have been underused due to their physical and chemical properties. Although most conventional crops are non-salt tolerant plants (glycophytes), halophytes can develop under high salinity concentrations and provide food, fodder and other uses, such as remediation and pharmaceuticals. Among them, Suaeda vera can be used for human consumption as forage and in phytoremediation. This study aims to optimize the cultivation of this species by producing a Technosol (TEC) using wastes as amendments to improve the properties of a Fluvisol (FLU). The amendments were constituted by cost-effective wastes: sludge and waste kieselguhr from breweries, medium sand, gravel limestone and biomass obtained from pruning. The FLU used in a microcosm assay was collected in the Tagus Estuary, close to Lisbon, Portugal. The soils properties, plants growth in Fluvisol and Technosol under the estuarine water (Ew) irrigation also collected in Tagus Estuary, were assessed. The microcosm assay was set up with four replicates and the substrata were incubated at 70% of the maximum water-holding capacity for 28 days, in the dark. After, seedlings obtained by germination in wet filter paper with deionised water were transplanted. The amendments, the FLU and the TEC were analysed for: pH, electrical conductivity (EC), concentrations of C_organic, P_extractable, K_extractable and N_total. The chemical characteristics of Ew were also analysed for pH, EC, Cl^–, HCO₃^–, Na, Ca, Mg, and the SAR was calculated. The plant growth parameters like stem length and biomass were determined. The FLU was slightly alkaline (pH 8), with a high EC (5.6 mS/cm) and low values of C_organic (20 g/kg), N_total (1.7 g/kg), P_extractable (1x10^-3 g/kg) and K_extractable (0.9 g/kg). Due to the wastes’ properties, the TEC showed a significant increase in C_organic (28 g/kg), N_total (2.5 g/kg), P and K_extractable (0.1 and 1.2 g/kg, respectively), in comparison with the FLU. The Ew was strongly saline (EC 22.1 mS/cm), had a neutral pH (7.78) and high concentration of Cl^- (7330 mg/L), HCO₃^- (267 mg/L), Na⁺ (4305 mg/L), Ca²⁺ (210 mg/L) and Mg²⁺ (538 mg/L). The Ew SAR value was high (157) but tolerated by halophytes. The individuals grown in the TEC presented a larger stem (18 cm) and a higher fresh biomass value (23 g) than individuals grown in the FLU. These results indicate that the wastes improved the Fluvisol properties being S. vera cultivation favoured if carried out in TEC. In a circular economy perspective, this study reveals that it is possible to cultivate a halophyte species with economic potential from underused resources as saline soils, wastes and brackish water.

How to cite: Cortinhas, A., Ferreira, T. C., Caperta, A. D., and Abreu, M. M.: Valorisation of cost-effective wastes and underused soils through Technosols construction for the Suaeda vera Forssk. ex J. F. Gmel. cultivation: a valued marine halophyte, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6811, https://doi.org/10.5194/egusphere-egu21-6811, 2021.

Mining is a crucial industry worldwide because of its economic and social importance. However, the increasing number of operating mines raises major concerns for health and the environment. The intense mining activity generates large quantities of wastes associated with several environmental problems. For example, the generation of acid mine drainages (AMD) by oxidation of sulphide ores stored in tailings deposits, leachates high concentrations of potentially harmful elements (PHEs), which poses severe pollution problems to the environment (aquatic and terrestrial ecosystems). This study evaluates the acid neutralisation capacity and the removal effectiveness of inorganic PHEs present in an AMD of different waste materials. This study is a first approach to future studies to develop pilot remediation studies using designed waste-derived Technosols. The waste used includes 4 mining wastes (iron oxide and hydroxide sludges [IO], marble cutting and polishing sludge [MS], gypsum spoil [GS], and carbonated waste from a peat extraction [CW]), 3 urban wastes (composted sewage sludge [WS], bio-stabilised material from municipal solid waste [BM], and vermicompost from pruning and gardening [VC]), and 3 agro-industrial wastes (2 solid olive-mill by-products [OW, OL] and composted greenhouse waste [GW]). All waste materials were spiked with the acidic water (AMD_L) prepared in the laboratory from the oxidation of pyritic tailings from the Aznalcóllar mine accident (1998). Afterward, they were stirred for 24 h and filtered, separating the waste (solid phase) from the leachate (liquid phase). In the leachate (AMD_L treated), pH_{(L) 1:5}, EC_{(L) 1:5}, and inorganic PHEs concentrations were measured, the latter by ICP-MS. The acidic water showed a strongly acidic character (pH_(L) ~ 2.89), high salinity (EC_(L) ~ 3.76 dS m^-1), and high concentrations of PHEs. Among them, As, Cd, Cr, Cu, Ni, Pb, Sb, Th, Tl, U, V, Y, and Zn stood out since they far exceed various legal limits widely used worldwide and/or because their high toxicity to humans, animals, plants or microorganisms. The most abundant were Zn (32.21 mg l^-1), Cu (6.24 mg l^-1), As (2.86 mg l^-1), Sb (0.82 mg l^-1), Pb (0.60 mg l^-1), and Cd (0.45 mg l^-1). All wastes were effective in neutralising the acidic pH_(L) of the AMD, as the leachates showed pH_(L) close to 7. In contrast, changes in the EC_(L) have been very irregular among the wastes used. In general, all wastes have been effective in adsorbing the PHEs. Inorganic wastes have been much more effective than organic ones, with adsorption efficiencies above 95% for many of the PHEs (particularly for those in higher concentrations). The waste with the best remediation behaviour were IO, CW, MS, GS, and VC. Conversely, GW and WS were the worst at removing PHEs present in AMD. Therefore, this study shows that many of wastes tested are suitable for the construction of Technosols from these wastes to prevent soil pollution by AMD discharge.

How to cite: Aguilar Garrido, A., Martínez Garzón, F. J., Paniagua López, M., Sierra Aragón, M., Fernández Ondoño, E., and Martín Peinado, F. J.: Potential of mining, agro-industrial, and urban wastes for the remediation of acidic mine water, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7093, https://doi.org/10.5194/egusphere-egu21-7093, 2021.

Cadmium is a metal distributed in low concentrations in the environment without biological function, but it can be toxic at high concentration for plants, animals, and/or humans. This element is one of the major soil pollutant, with high mobility and availability under the conditions of many agricultural soils. The use of nanoremediation techniques can be an effective solution for the in situ recovery of contaminated soils with Cd, although the existing information about the consequences of using nanoparticles in soils is still very scarce. In this context. Hydroxyapatite nanoparticles can be an effective amendment for remediation of soils. Quinoa (Chenopodium quinoa Will) is a seed-producing crop that has been cultivated in the Andes for several thousand years but with a good adaptation to different climatic conditions. Currently, quinoa is an emerging multipurpose crop in other parts of the world, due to its high nutritional potential for both human food and animal feedstock and a good alternative to cereals, leading to significant demand and, consequently, cultivation. In this study, we investigated the capacity of hydroxyapatite nanoparticles for recovering artificially contaminated soils with Cd where grown quinoa. For this, seeds of C. quinoa were sown in two different soil (Arenosol and Anthrosol) artificially contaminated with Cd²⁺ (0; 5, 25 and 50 mg kg^-1) and amended or not with 1% (w/w) of hydroxyapatite nanoparticles. The pot assay was carried out under controlled conditions and in a greenhouse for three months. Initial soils were characterized physicochemically and at the end of the assay multielemental concentrations were determined in soil (total and available fraction and plants (shoots). Germination rate, shoot height and dry biomass were measured, as well as pigments, glutathione, ascorbate and H₂O₂ contents were analysed in plant shoots in order to evaluate plant development and their physiological status. In parallel, a sequential chemical extraction was carried out to determine the Cd distribution in the different geochemical soil phases. Preliminary results indicated that hydroxyapatite nanoparticles have a high capacity to retain Cd. These nanoparticles seem to favour C. quinoa growth even with the highest concentration of Cd added. Therefore, this study will serve as a basis for further scientific research on the potential use of hydroxyapatite in agriculture soils with different characteristics and Cd problems for secure C. quinoa cultivation.

Acknowledgements

This research and postdoc contract from Arenas-Lago D. was supported by the project ED481D 2019/007 (Xunta de Galicia), and Portuguese funds through Fundação para a Ciência e Tecnologia within the scope of the project UID/AGR/04129/2020 (LEAF).

How to cite: Arenas Lago, D., Forján Castro, R., Santos, E. S., Arán, D., and Arias Estévez, M.: Use of hydroxyapatite to reduce Cd pollution in agriculture soils for Chenopodium quinoa cultivation, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10595, https://doi.org/10.5194/egusphere-egu21-10595, 2021.