Geochemical investigations of potentially toxic trace elements in urban sediments of Idrija

Urban areas and associated human activities (industry, traffi, processes of mining and ore extracting, etc.) have induced anthropogenic emissions of potentially toxic trace elements (PTTE), which can present risk to living organisms and ecosystems in case of enriched levels. An example of such area in Slovenia is the Idrija town, the central part of the second largest Hg mining district in the world, which is heavily contaminated with Hg in all environmental compartments. The knowledge about levels and distribution of other PTTE in Idrija is very limited due to the outstanding Hg related problems. In this study the geochemical investigation of PTTE (As, Cd, Co, Cr, Cu, Mo, Ni, Pb and Zn) was performed in urban stream and road sediments of Idrija town for the fist time. In addition, solid phases of PTTE were observed using SEM/EDS and their potential sources were assessed. The results show that the levels of PTTE in urban stream and road sediments are mostly below international guidelines, except for Cu some high values were measured in road sediments. The highest Cu level was determined in the vicinity of a commutator production industry. The associations of Cu with other elements in solid phases are very diverse, which is why the analyses could not reveal the specifi source of high Cu levels

Geochemical baseline for chemical elements in top- and subsoil of Idrija

This study is a continuation of our previous study (Bavec et al., 2015), where the geochemical baseline levels of potentially harmful elements (As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb and Zn) in Idrija top- and subsoil (0-10 cm and 10-20 cm) at 45 locations were reported. Here we summarise our previous work and present baseline levels of additional 33 elements (Ag, Al, Ba, Be, Bi, Ca, Ce, Cs, Fe, Ga, Hf, In, K, La, Li, Mg, Mn, Nb, P, Rb, S, Sb, Sc, Se, Sn, Sr, Th, Ti, Tl, U, V, Y and Zr) in order to round off the fist systematic geochemical survey of soil in Idrija town and establish a data set of soil elements, which will serve as a baseline for monitoring future changes in the soil chemical composition of the studied area. The baseline levels were determined after aqua regia digestion, their statistical distribution was examined and the medians were compared to the recently established European grazing land and Maribor urban soil medians. To investigate relationships between elements, a correlation-matrix-based hierarchical clustering method was performed and the spatial distribution of their highest levels was examined. The results showed that in general, the median levels of elements in Idrija soil are mostly similar or slightly higher than in European and Maribor soil, with exception of Hg. Elements Al, Bi, Ca, Ce, Co, Cr, Cs, Fe, Ga, Hf, La, Li, Mg, Mn, Nb, Ni, Rb, S, Sc, Th, Ti, Tl, V, Y and Zr are enriched in the rural surroundings, while elements Ag, Ba, Cu, Hg, P, Pb, Se, Sb, Sn and Zn are enriched only partly in the rural surroundings, but mostly in the urban part of the study area. It is assumed that elements, which are enriched only in the rural surroundings, are of natural origin, while elements, which are enriched also in the urban area, are to a certain extent inflenced by anthropogenic activities

The environmental impact of historical Pb-Zn mining waste deposits in Slovenia

Mining waste deposits (MWDs) represent significant and constant pollution source for the environment worldwide, thus it is very important to identify and diminish their environmental impacts. The aim of this study was to determine long-term environmental impacts and their temporal variations of MWDs in Pb–Zn mining districts in Slovenia and assess stability of potentially harmful element (PHE)-bearing phases in stream water. The results showed that investigated MWDs are important source of PHEs in stream sediments and that PHEs mostly occur as fine-grained and liberated PHE-bearing ore minerals. MWDs have generally stronger impact on sediments of smaller streams draining MWDs and main streams close to their confluences, however, fine-grained PHE-bearing material is transported along major watercourses over long distances causing regional pollution. Main ore minerals are mostly soluble in stream water. However, measured PHE leaching potential of MWDs is negligible. PHE levels in stream waters are thus low, demonstrating that drainage of MWDs predominantly contributes to PHE pollution in solid particulate form. Possible long-term remediation solution that would reduce environmental impact is recovery of metals from fine grain size fractions of MWDs, which could become an effective practice in sustainable management of historical MWDs. However, further studies of MWDs’ secondary resource potential, processing technology and evaluation of environmental aspects of extraction are needed

Analiza vpliva vgrajenega sanacijskega materiala na rekultivacijo opuščenega peskokopa

For the rehabilitation and reclamation of abandoned sandpit in Drtija (Moravče), construction composites are used as rehabilitation materials. Construction composites are produced by mixing of recycled non-hazardous waste and natural materials. In the presented study, the chemical composition of the rehabilitation materials, which are already built-in on abandoned surfaces and impact analysis on recultivation of the upper layer, was evaluated. For this purpose, the rehabilitation materials were sampled at 3 locations with test pit excavations up to a depth of 3 m, surrounding topsoils (0-10 cm) at 2 locations and leachate at 1 location. The results show that the in-built rehabilitation materials are burdened with metals (Cd, Cr, Cu, Ni, Pb, Zn), which are, however, poorly soluble under the given conditions. The latter is also indicated by the concentrations of metals in the leachate, which are within the lower limit of quantification (LOQ) area. Regarding organic substances, the presence of phenol and formaldehyde was found in the leachate. In rehabilitation materials only phenol was found in two samples. Considering that the rehabilitation materials will be covered with a layer of clay and humus and will be tilled or afforested as part of the final rehabilitation step, the impact of rehabilitation materials on the reclaimed soil is not expected. According to results of this study recultivaton of the upper layer with planting of woods is recommended.V okviru sanacije opuščenega peskokopa Drtija (Moravče) se kot sanacijski material uporabljajo gradbeni kompoziti, ki se proizvajajo z mešanjem nenevarnih in inertnih odpadkov ter naravnega avtohtonega materiala (kremenov pesek, glina). V prispevku smo ugotavljali kemično sestavo že vgrajenih sanacijskih materialov ter vpliv le-teh na rekultivacijo površinskih vrhnjih plasti. V ta namen smo z bagrskimi izkopi vzorčili sanacijski material na 3 lokacijah do globine 3 m, okoliška površinska tla (0-10 cm) na dveh lokacijah ter izcedno vodo na 1 lokaciji. Rezultati kažejo, da so vgrajeni sanacijski materiali obremenjeni s kovinami (Cd, Cr, Cu, Ni, Pb, Zn), ki pa so v danih razmerah slabo topne. Slednje nakazujejo tudi koncentracije kovin v izcedni vodi, ki se pojavljajo znotraj območja spodnje meje določanja (LOQ). Od organskih snovi so v izcedni vodi prisotne povečane vsebnosti fenola in formaldehida, ki pa v sanacijskem materialu nista zaznavna, z izjemo fenola v dveh vzorcih. Vgrajeni sanacijski materiali bodo v sklopu končne sanacije prekriti s plastjo gline in humusa ter zatravljeni ali pogozdeni, zato ugotavljamo, da vpliv sanacijskih materialov na rekultivacijo vrhnje plasti ni pričakovan. Glede na rezultate je najbolj smiselna rekultivacije vrhnje plasti s pogozditvijo

Contents of potentially toxic elements in sediments and waters of the Meža river and its tributaries draining mine waste deposits

Predstavljeni so rezultati spremljanja vsebnosti potencialno strupenih elementov (PSE) v sedimentih (v letih 2013, 2017, 2020) in vodah (v letih 2017, 2020) reke Meže ter njenih pritokov, ki odvodnjavajo odlagališča rudarskih odpadkov. Skupno 13 vzorčnih mest je vzpostavljenih v vzorčni shemi, ki omogoča dolgoročno opazovanje vpliva odlagališč rudarskih odpadkov. V sedimentih so zaradi vplivov več kot 300-letnega delovanja rudarsko-predelovalne industrije močno povečane vsebnosti PSE, predvsem Pb, Zn, Cd, Mo in As, ki s časom precej nihajo. Razlike v vsebnostih na istih lokacijah v različnih letih so najbolj izrazite v pritokih reke Meže, ki drenirajo odlagališča rudarskih odpadkov. Na vsebnosti imajo pomemben vpliv hidrološki pogoji, saj so ob višjem vodostaju in višjem pretoku vsebnosti PSE večje. Vodna erozija odlagališč ima pomemben vpliv na dotok onesnaženega materiala v vodotoke. V nasprotju s pritoki, v zgornjem toku reke Meže nismo opazili večjega vpliva višjega vodostaja in pretoka na vsebnosti PSE v sedimentih. Dolvodno od Žerjava so nihanja vsebnosti med posameznimi leti oz. različnimi hidrološkimi pogoji tudi v Meži večja. Predstavljeni rezultati kažejo, da so v sedimentih reke Meže in njenih pritokov vsebnosti Pb, Zn, Cd, Mo in As zelo velike ter krepko presegajo zakonsko določeno kritično vrednost za tla. V površinski vodi so vsebnosti PSE lokalno povečane in se s časom bistveno ne spreminjajo. Glede na primerjavo z zakonodajnimi smernicami, so v obravnavanih vodah lokalno presežene koncentracije Pb, Cd in Zn. Ocenjujemo, da je dinamika obremenjenosti sedimentov reke Meže s PSE vzdolž krajev Črna na Koroškem, Žerjav in Mežica zelo kompleksna. Poleg odlagališč rudarskih odpadkov na vsebnosti PSE v sedimentih in vodah vplivajo tudi razpršeni viri v okolju, kot so onesnažena tla in poplavne ravnice ter njihova različna stopnja onesnaženosti, saj je okolje obremenjeno zaradi dolgoletnih rudarskih in talilniških dejavnosti. Dodaten okoljski vpliv ima morda tudi sedanja industrijska dejavnost v dolini reke Meže.The results of the monitoring of the contents of potentially toxic elements (PTE) in sediments (2013, 2017, 2020) and waters (2017, 2020) of the Meža River and its tributaries, which drain mining waste deposits, are presented. A total of 13 sample sites were established in a sample scheme that enables long-term observation of the impact of mining waste deposits. In the sediments, the content of PTE, especially Pb, Zn, Cd, Mo and As, is greatly elevated and fluctuates with time. The study area is affected by more than 300 years of mining and ore processing industry. The differences in the contents in various years are most pronounced in the Meža River tributaries, which drain the mining waste dumps. Hydrological conditions have a significant influence on the contents in sediments, as PTE content increases with higher water level and higher water flow. Water erosion of mining waste dumps has a significant impact on the discharge of contaminated material into watercourses. In contrast, in the upper part of the Meža River, we did not observe strong influence of higher water level on the content of PTE in the sediments. Fluctuations in the content between individual years and fluctuations between various hydrological conditions are higher again in the middle part of the the Meža river, downstream from Žerjav. The presented results demonstrate that the contents of Pb, Zn, Cd, Mo and As in the sediments of the Meža River and its tributaries are very high and that they by far exceed the legislative critical value for the soil. PTE contents in the surface water are elevated in some locations and do not change significantly over time. The local concentrations of Pb, Cd and Zn exceed the legislative guidelines. We estimate that the dynamics of the sediment load in the Meža River along the towns of Črna na Koroškem, Žerjav and Mežica is very complex. In addition to mining waste deposits, the content of PTE in sediments and waters is also affected by scattered sources in the environment, such as contaminated soil and floodplains and their varying degrees of pollution, as the environment has been burdened by long-term mining, ore processing and smelting activities. Current industrial activity may also have an additional environmental impact

Overview of existing information on important closed (or in closing phase) and abandoned mining waste sites and related mines in Slovenia

The presented work provides a comprehensive inventory of data on closed (or in closing phase) and abandoned underground and surface mines and mining waste sites in Slovenia, collected within the framework of the Geological Survey of Slovenia (GeoZS) over the last two decades. Furthermore, a detailed overview of information on closed and abandoned mining waste sites in Slovenia is given. In order to establish the inventory, a definition of the work methodology, a comprehensive research of the archived and published literature, and the harmonisation and management of the collected data was carried out. Based on a selected methodology, the inventory contains information on 33 metal mines, 43 coal mines, 51 non-metallic mineral resource mines, 156 waste sites from metal mines and 18 waste sites from coal mines. The inventory is in the open access Google Earth file. It provides a basis for further research into the environmental impact of mining waste, which has been carried out since the EU Directive on the management of waste from extractive industries (Directive 2006/21/EC hereafter) was adopted into national law. In general, about 11,621,333 m3 of waste sites from metal mines and 76,188,000 m3 of waste sites from coal mines are covering about 678 hectares of Slovenian territory. More than half (64 %) of the waste from metal mines was produced in the Mežica lead and zinc mine, while the other two mines with a still significant share of produced waste were the Idrija mercury mine (18 %) and the Žirovski vrh uranium mine (15 %). Among the closed coal mines, the largest amount (46 %) of waste was generated by the coal mine Trbovlje-Hrastnik, while the other two coal mines with still significant share of waste produced were Kočevje (28 %) and Kanižarica (17 %)

Koroška Bela alluvial fan – The result of the catastrophic slope events; (Karavanke Mountains, NW Slovenia)

The Koroška Bela alluvial fan deposits were investigated to determine the genesis of the fan and the source area of sediments. The alluvial fan is composed of a sequence of diamicton layers, and related subaeric sediments that were deposited by multiple mass flow events, in some cases certainly by debris flows. The predominant sources ofsediments are tectonically deformed clastic and partly carbonate Carbonifferous and Permian rocks. In diamictons also pebbles of other rocks from the hinterland are present. These were eroded from the channel of Bela during the mass flow events. We estimate the future debris flow hazard along Bela stream as high

Geochemical background and threshold for 47 chemical elements in Slovenian topsoil

Geochemical background and threshold values need to be established to identify areas with unusually high concentrations of elements. High concentrations are caused by natural or anthropogenic processes. The <2 mm fraction of 817 collected topsoil (0 – 10 cm) samples at a 5 × 5 km grid on the territory of Slovenia was analysed. Results are used here to establish the geochemical background variation and threshold values, derived statistically from the data set, in order to identify unusually high element concentrations for these elements in the soil samples. Geochemical threshold values were determined following different methods of calculation for (1) whole of Slovenia and (2) for 8 spatial units determined on the base of geological structure, lithology, relief, climate and vegetation. Medians and geochemical thresholds for whole of Slovenia were compared with data for Europe and for southern Europe separately, since large differences in the spatial distribution of many elements are observed between northern and southern Europe. Potentially toxic elements (PTEs), namely As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, and Zn, are of particular interest. Medians of these PTE elements are all higher in Slovenia than in southern Europe. Medians of Pb and Mo are 1.5 times higher and medians of Hg and Cd are even more than 2 times higher in Slovenia. Geochemical thresholds for As, Cr, Co, Ni, Sb and Zn are of similar values in both Slovenia and southern Europe and some lower for Cu and Ni. Up to 1.5 times higher are tresholds in Slovenia for Mo and Pb and more than 2.5 times higher for Cd and Hg. These values were then compared to existing Slovenian soil guideline values for these elements

ORAMA Project - D6-6 Technical Final Report and Recommendations

Securing the sustainable access to and supply of raw materials, and particularly of Critical Raw Materials (CRM), is of high importance for the European economy. Complex primary and secondary resources contain many different raw materials. The inability to easily produce reliable statistics about reserves, resources, stocks, and flows of raw materials limits the understanding of global trends in resource availability and hampers formulation of mineral and waste policies. This ultimately affects supply chain security and strategic decisions by industry. Hence, it is an issue of great concern for the European Commission (EC) and many other stakeholders. The ORAMA project (Optimising quality of information in RAw MAterial data collection across Europe) seeks to contribute to better supply of raw materials by improving the quality of harmonised raw materials data collection and information sharing among the different levels within the European Union (EU).Data collection practices for primary and secondary raw materials (PRM and SRM) face specific challenges in EU Member States (MS). For PRM data, the main concerns are related to data availability, geographical coverage, accessibility, harmonisation, interoperability, quality, and thematic coverage. The reporting of primary mineral resources and reserves statistics is currently carried out by a wide variety of systems, standards or codes which are not directly comparable. Hence, it is currently impossible to produce reliable pan-European figures for resources for any mineral commodity. ORAMA addresses these issues by recommending a single standard for reporting of resource data, the United Nations Framework Classification (UNFC), a framework for reporting mineral resource data developed by the UN. To enable and encourage data providers to adopt this standard for European PRM data, the ORAMA project has developed resources in the form of a range of training materials and good practice examples.The ORAMA project demonstrates that the analysis of various classifications and reporting systems that sit within the INSPIRE (Infrastructure for Spatial Information in the European Community) concept and data services, are not opposing but rather integral elements of the proper European level data collection and production of information for PRM and SRM. The use of UNFC/UNRMS (United Nations Resource Management System) in the framework of the INSPIRE compliant data service can significantly contribute to sustainable resource management taking into account not only geological knowledge and raw materials potential but also environmental and social issues, based on using the national/regional legislative elements for exploration and exploitation as well.In the case of SRM, the challenges are somewhat different. Regarding mining waste (MIN), the lack of information on deposit characteristics (composition, volumes, and suitable processing technology) is a huge barrier in the identification of recovery potential of the valuable materials that remain in the waste. Furthermore, the lack of a single reporting standard commonly accepted at EU level has created a dispersion of existing information in various systems and project deliverables. In the case of electrical and electronic equipment (EEE) and batteries, beyond the lack of harmonisation, substantial data gaps exist for the market inputs, materials consumption and stocks, and for waste electrical and electronic equipment (WEEE) for unaccounted flows ending up being scavenged, metal scrap and export channels. For vehicles, huge amounts of data, both on stocks and flows and on composition, are systematically collected by authorities and the manufacturing industry, but are only publicly available in a somewhat too aggregated form (placed on market (POM), stock, waste flows) or not at all (composition data).Even when collected, the reporting of the composition of these flows on a product, component and materials level are currently poorly described across all MS, and when actually ending up in recycling processes, the recovery efficiency for all elements and CRMs, in particular, is disappointing. In order to improve the data collection and reporting practices for SRM a structured review and inventory were made followed by a data gap analysis which resulted in the developments of recommendations and subsequently the selection of 6 case studies. The SRM case studies tackle the main data gaps encountered in the analysis and developed tools that will enable the improvement and harmonisation of collection and reporting practices in MS, treatment facilities, data providers, academia among others.The ORAMA project recommends to establish more structured and continuous funding for realising and maintaining a European data infrastructure for tracking both PRM and SRM. The current project-by-project based financing is insufficient and not sustainable to properly track and understand Europe’s strengths and weaknesses in the early resource intensive stages of global supply chains