Supplementary information for the article: Sakan, S.; Mihajlidi-Zelić, A.; Škrivanj, S.; Frančišković-Bilinski, S.; Đorđević, D. An Integrated Approach in the Assessment of the Vlasina River System Pollution by Toxic Elements. Frontiers in Environmental Science 2022, 10. https://doi.org/10.3389/fenvs.2022.909858.

Increasing pollutant levels in surface water are a very important problem in developing countries. In Serbia, the largest rivers are transboundary rivers that cross the border already polluted. Taking this into account, evaluation of the distribution characteristics, ecological risk, and sources of toxic elements in river water and surface sediments in the watercourses of the Vlasina watershed is of great significance for the protection of water resources in Serbia. A total of 17 sediment and 18 water samples were collected and analyzed by Inductively Coupled Plasma—Optical Emission spectrometry (ICP-OES) and Inductively Coupled Plasma—Mass spectrometry (ICP-MS) to determine micro- and macroelements contents. The geo-accumulation index (Igeo) was applied to determine and classify the magnitude of toxic element pollution in this river sediment. The contents of the studied toxic elements were below water and sediment quality guidelines. For studied river water, results of principal component analysis (PCA) indicated the difference in behavior of Cr, Mn, Ni, Cu, and As and V, respectively. Cluster analysis (CA) classified water samples according to As and Cu content. The PCA results revealed that lead in river sediments had different behavior than other elements and can be associated mainly with anthropogenic sources. According to the degree of Igeo, the majority of sediments in the Vlasina region were uncontaminated regarding studied toxic elements. The origin of elements is mostly from natural processes such as soil and rock weathering.Related to published version: [https://cherry.chem.bg.ac.rs/handle/123456789/5501]Related to accepted version: [https://cherry.chem.bg.ac.rs/handle/123456789/5501

An Integrated Approach in the Assessment of the Vlasina River System Pollution by Toxic Elements

Increasing pollutant levels in surface water are a very important problem in developing countries. In Serbia, the largest rivers are transboundary rivers that cross the border already polluted. Taking this into account, evaluation of the distribution characteristics, ecological risk, and sources of toxic elements in river water and surface sediments in the watercourses of the Vlasina watershed is of great significance for the protection of water resources in Serbia. A total of 17 sediment and 18 water samples were collected and analyzed by Inductively Coupled Plasma—Optical Emission spectrometry (ICP-OES) and Inductively Coupled Plasma—Mass spectrometry (ICP-MS) to determine micro- and macroelements contents. The geo-accumulation index (Igeo) was applied to determine and classify the magnitude of toxic element pollution in this river sediment. The contents of the studied toxic elements were below water and sediment quality guidelines. For studied river water, results of principal component analysis (PCA) indicated the difference in behavior of Cr, Mn, Ni, Cu, and As and V, respectively. Cluster analysis (CA) classified water samples according to As and Cu content. The PCA results revealed that lead in river sediments had different behavior than other elements and can be associated mainly with anthropogenic sources. According to the degree of Igeo, the majority of sediments in the Vlasina region were uncontaminated regarding studied toxic elements. The origin of elements is mostly from natural processes such as soil and rock weathering.Supplementary material: [https://cherry.chem.bg.ac.rs/handle/123456789/5503

Problemi u životnoj sredini i po zdravlje prouzrokovani proizvodnjom energije u Srbiji

Still, now the main energy production in Serbia (70%) is from low-caloric lignite of Kolubara and Kostolac basins which contain harmful elements: As, Be, Co, Mo, Mn, Ni, Pb, Se, Sb, V, U, Th, Ra, Rn etc. Six Serbian CFPPs generate about 6,000,000 t/year of ash enriched by toxic elements which are being deposited on fertile arable land and emitted in ambient air. About 1600 hectares of fertile soil is permanently contaminated with toxic elements from ash disposals endangering surface and underground waters. An increased carcinogenic risk was observed due to arsenic in ambient air, contained in the respiratory particles of the finest fraction. CFPPs are identified as their emission sources. In recent years, small hydropower plants have been installed on last mountains clean rivers in Serbia based on decades old echnical projects and old water data, which do not include the climate change factors. Our research has shown the consequence on Vlasina River, making it the swamp quality water and enhanced erosion processes. Particularly dangerous in mountainous areas is of landslides and torrential floods induced by enormous precipitation due to climate change. Problems of the water supply of Vlasotince municipality are already evident. Serbia has many other possibilities for clean and low carbon energy production: 1) biogas production from biomass with which Serbia is globally one of the richest countries, 2) in summer period Serbia is country with Mediterranean climate and solar energy is easy to use, 3) Serbia is rich with underground geothermal waters that are not used for domestic and public heating, 4) energy production from methane from farms and waste disposal, 5) wind energy etc. The most important approach must be towards energy efficiency in the public and domestic sector and to prosumers concept. With this approach, Serbia does not need any CFPPs and especially small hydro power plants.International scientific conference Environmental impact of illegal construction, poor planning and design IMPEDE 2019, 10 – 11 October 2019, Belgrade, Serbi

Magnetic methods applied in environmental research in Serbia for investigation of Vlasina region sediments and soils

Vlasina is a beautiful plateau in the south-east of Serbia. It is a natural protected area, known due to unspoiled nature, clean springs and Vlasina Lake, which is the largest artificial lake in Serbia, located at 1.213 m a.s.l. Vlasina River has its spring under the Vlasina Lake dam and it is about 70 km long tributary of South Morava River. Because of its location in a sparsely inhabited mountain region and because of lack of industrial pollutants in this area, Vlasina is considered to be one of the cleanest Serbian rivers. We aim to introduce the relatively new, fast and cheap method of magnetic susceptibility (MS) in environmental research in Serbia, in addition to usually used geochemical and mineralogical methods. Until recently MS measurements have not been used for this purpose in the broader region around Serbia, e.g. first such measurements in Croatia were performed by Francišković-Bilinski (2008) on the samples from Kupa River watershed. ´ Measured MS values in Vlasina samples are mostly very low, with several locations where values are a bit higher; they range from 0.02 x 10-3 to 1.113 x 10-3 SI units. Statistical boxplot analysis of anomalies has shown that 3 extremes (anomalies of higher degree) and 1 outlier (anomaly of lower degree) exist. Correlation analysis between MS and measured chemical elements has shown that strong correlations do not exist. From that it could be concluded that in Vlasina samples there is no significant anthropogenic influence. In the case of Vlasina strongest correlation was observed with Mo (0.43), then with Ag (0.29). Correlations > 0.10 are determined between MS and following elements: Zn (0.17); Cu (0.12); Pb (0.17); Ba (0.13); Mn (0.10); Ti (0.20); V (0.21); In (0.16); Sn (0.16); Tm (0.10); Lu (0.12); Hg (0.16); Bi (0.13); Th (0.15) and U (0.24). Those correlations support our hypothesis about natural (geogene) origin of those elements from metamorphic rocks, which prevail in this region. Q-mode cluster analysis was also performed. It also supports our claim that in Vlasina region there is no significant anthropogenic influence. Cluster 1 from Vlasina is correlated with carbonates, as mean Ca value in this cluster is 8 times higher than in Cluster 2. Cluster 1 contains samples from 4 locations, which are located in the area where carbonate rocks (mainly limestones) are present. On those locations also statistical anomalies of Ca were found using boxplot method. In this carbonate cluster concentrations of majority of heavy metals are lower than in Cluster 2, also MS value is lower, what is due to the fact that in carbonates metal concentrations are naturally lower.European Geosciences Union (EGU) General Assembly 2019, Vienna, Austria, April 7-12, 201

Toxic elements in soils from Vlasina region

In this research, the optimized three-step sequential extraction procedure for the fractionation of micro- and macroelements, proposed by Commission of European Communities of reference (BCR) has been applied to the soils from Vlasina region. Element concentrations in the extracts were determined using ICP OES. Magnetic susceptibility (MS) was measured using magnetic susceptibility meter. The index of geoaccumulation (Igeo) has been applied to assess trace elements distribution and contamination in studied soils. An assessment of toxic element levels in the studied soils is made by comparing the total contents of the extracted elements with the limit values determined by Serbian Regulation. Metal fractionation showed that easily mobile form is dominant for lead and manganese. Other elements (Zn, Ni, Cr, Co, As, Cu, Cd, and V), found dominantly in the residual fraction indicate that these elements may be an indicator for natural sources input. Obtained results indicated that the soils from Vlasina region were not contaminated with toxic elements and the origin of elements is mostly from natural processes such as soil and rock weathering

Magnetic properties as indicators of toxic elements pollution in surface sediments of the Vlasina River (Serbia) and Kupa River (Croatia)

The relationships between magnetic susceptibility (MS) and elemental variations have been the focus of considerable study in the fields of environmental assessment. The aim of this study was to apply a rapid and inexpensive, low-field magnetic susceptibility method to stream sediments from Vlasina (Serbia) and Kupa (Croatia) river basins, and discuss the relationships between MS and content of 26 studied elements using statistical approaches. In this research, magnetic susceptibility was measured using SM30, a small magnetic susceptibility meter with a very high sensitivity of 1 × 10-7 SI. Inductively Coupled Plasma Optical Emission Spectroscopy was used to determine the concentration of the studied elements, after sequential extraction procedure (Sakan et al., 2016). Total concentrations of each element were determined as the sum of concentrations determined in each fraction. The Kupa River basin, occupies the west-central part of Croatia and is shared by two neighboring countries (Slovenia, Bosnia and Herzegovina). The Kupa itself is a tributary to the Sava River and meets the latter at Sisak after traversing a distance of 294 km. The river basin is one of the most significant water resources in Croatia (Frančišković-Bilinski et al., 2012). Vlasina River Basin covers an area of 1061.72 km² and covers the south eastern part of Serbia. The total length of Vlasina River is 65.9 km. The largest part of the geological base of the Vlasina River Basin belongs to the Serbo-Macedonian mass, formed in the Palaeozoic (Carbon-Perm) (Durlević et al., 2019). Correlation analysis was performed to reveal statistical correlations between MS and 26 elements analyzed by ICP-OES in Kupa sediment samples. Ten of them showed negative correlation (As, B, Ba, Fe, K, Li, Mg, Na, P, S), while other elements showed positive. Chromium showed excellent correlation with MS (0.91) and is element with the highest correlation to MS, what could indicate its anthropogenic origin. Element with strongest correlation to MS after Cr is vanadium (0.62), followed by Mn (0.52), Al (0.52) and Cd (0.50). All other elements have rather weak correlation with MS, among which highest are those of Sr (0.45), Zn (0.35), Be (0.28), Co (0.27), Pb (0.27) and Ti (0.26). Measured MS values in Vlasina samples are mostly very low, with several locations where values are a bit higher; they range from 0.02 x 10-3 to 1.113 x 10-3 SI units. The strongest correlation was observed with Mo (0.43), then with Ag (0.29). Correlations > 0.10 are determined between MS and following elements: Zn (0.17); Cu (0.12); Pb (0.17); Ba (0.13); Mn (0.10); Ti (0.20); V (0.21); In (0.16); Sn (0.16); Tm (0.10); Lu (0.12); Hg (0.16); Bi (0.13); Th (0.15) and U (0.24). Correlation analysis between MS and measured chemical elements has shown that strong correlations do not exist. From that it could be concluded that in Vlasina samples there is no significant anthropogenic influence

Characterisation of the chemical composition in geothermal hot springs in Iceland and Serbia

Geothermal hot springs are located in various tectonic environment proving environmentally friendly energy source to fulfil energy demand. The geothermal energy sources are often associated with divergent tectonic plate boundaries as in the Icelandic case or in orogeny geological settings as in the Serbian case. The chemical composition of a hot spring is a signature of the sub-surface geology and its chemical composition. Hence, the comparison of the chemical composition of geothermal sources can help us provide more detailed information prior to sub-surface exploration. In order to assess the suitability of geothermal sources we analysed the chemical composition in Icelandic and Serbian geothermal sources. For this purpose we collected samples from various hot springs in Iceland and in Serbia and analysed them using ion chromatography (IC) to determine anion concentrations and using inductively coupled plasma-optical emission spectrometry (ICP – OES) to determine cation and other element concentrations. The preliminary results reveal that chemical composition reflects differences between locations of sampling as well as the depths from which the fluid was extracted. Preliminary data obtained from the chemical analysis from sources located near to the Ocean in Iceland indicate a high concentration of Na+, K+ and Cl- ions, revealing an inflow of sea water. The data from the chemical analysis of the samples obtained from sources in Serbia, however, shows a high concentration of Na+, Ca2+ and Mg2+. These results reveal that Serbian geothermal sources are characterized by very hard water and accordingly have to be used with precaution. Further analysis of the temporal evolution of the chemical composition is advisable before sub-surface exploration.European Geosciences Union (EGU) General Assembly 2019, Vienna, Austria, April 7-12, 201

Size distributed aerosol mass concentration and chemical composition in Belgrade during summer-autumn 2008

Physical and chemical characterizations of the atmospheric aerosol were carried out in urban area of Belgrade. This work focuses on the size-segregated aerosol chemical composition observed during the summer-autumn 2008th. Aerosol samples were submitted to gravimetric and chemical analyses. Mean random uncertainties associated with determination of Na+ , NH4 +, K+, Mg2+, Ca2+, Cl-, NO3- and SO42- were assessed

Trace elements in size-segregated urban aerosol in relation to the anthropogenic emission sources and the resuspension

Size segregated particulate samples of atmospheric aerosols in urban site of continental part of Balkans were collected during 6 months in 2008. Six stages impactor in the size ranges: Dp ≤ 0.49 μm, 0.49 < Dp ≤ 0.95 μm, 0.95 < Dp ≤ 1.5 μm, 1.5 < Dp ≤ 3.0 μm, 3.0 < Dp ≤ 7.2 μm, and 7.2 < Dp ≤ 10.0 μm was applied for sampling. ICP-MS was used to quantify elements: Al, As, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, K, Li, Na, Ni, Mg, Mn, Pb, Sb, V, and Zn. Two main groups of elements were investigated: (1) K, V, Ni, Zn, Pb, As, and Cd with high domination in nuclei mode indicating the combustion processes as a dominant sources and (2) Al, Fe, Ca, Mg, Na, Cr, Ga, Co, and Li in coarse mode indicating mechanical processes as their main origin. The strictly crustal origin is for Mg, Fe, Ca, and Co while for As, Cd, K, V, Ni, Cu, Pb, and Zn dominates the anthropogenic influence. The PCA analysis has shown that main contribution is of resuspension (PC1, σ2 ≈ 30 %) followed by traffic (PC2, σ2 ≈ 20 %) that are together contributing around 50 % of elements in the investigated urban aerosol. The EF model shows that major origin of Cd, K, V, Ni, Cu, Pb, Zn, and As in the fine mode is from the anthropogenic sources while increase of their contents in the coarse particles indicates their deposition from the atmosphere and soil contamination. This approach is useful for the assessment of the local resuspension influence on element’s contents in the aerosol and also for the evaluation of the historical pollution of soil caused by deposition of metals from the atmosphere

An interlaboratory comparison of aerosol inorganic ion measurements by ion chromatography : Implications for aerosol pH estimate

Water-soluble inorganic ions such as ammonium, nitrate and sulfate are major components of fine aerosols in the atmosphere and are widely used in the estimation of aerosol acidity. However, different experimental practices and instrumentation may lead to uncertainties in ion concentrations. Here, an intercomparison experiment was conducted in 10 different laboratories (labs) to investigate the consistency of inorganic ion concentrations and resultant aerosol acidity estimates using the same set of aerosol filter samples. The results mostly exhibited good agreement for major ions Cl-, SO2-4, NO-3, NHC4 and KC. However, F-, Mg2C and Ca2C were observed with more variations across the different labs. The Aerosol Chemical Speciation Monitor (ACSM) data of nonrefractory SO2-4, NO-3 and NHC4 generally correlated very well with the filter-analysis-based data in our study, but the absolute concentrations differ by up to 42 %. Cl-from the two methods are correlated, but the concentration differ by more than a factor of 3. The analyses of certified reference materials (CRMs) generally showed a good detection accuracy (DA) of all ions in all the labs, the majority of which ranged between 90 % and 110 %. The DA was also used to correct the ion concentrations to showcase the importance of using CRMs for calibration check and quality control. Better agreements were found for Cl-, SO2-4, NO-3, NHC4 and KC across the labs after their concentrations were corrected with DA; the coefficient of variation (CV) of Cl-, SO2-4, NO-3, NHC4 and KC decreased by 1.7 %, 3.4 %, 3.4 %, 1.2 % and 2.6 %, respectively, after DA correction. We found that the ratio of anion to cation equivalent concentrations (AE/CE) and ion balance (anions-cations) are not good indicators for aerosol acidity estimates, as the results in different labs did not agree well with each other. In situ aerosol pH calculated from the ISORROPIA II thermodynamic equilibrium model with measured ion and ammonia concentrations showed a similar trend and good agreement across the 10 labs. Our results indicate that although there are important uncertainties in aerosol ion concentration measurements, the estimated aerosol pH from the ISORROPIA II model is more consistent