Spatial distribution of multielements including lanthanides in sediments of Iron Gate I Reservoir in the Danube River

Recent studies show that lanthanides (Ln) are becoming emerging pollutants due to their wide application in new technologies,but their environmental fate, transport, and possible accumulation are still relatively unknown. This study aims to determinemajor and trace elements including Ln in the Danube River sediment which either belong or close to the Iron Gate Reservoir. TheIron Gate Reservoir is characterized by accumulation of sediments as an effect of building hydropower dam Iron Gate I. Thesurface sediments were collected on the Danube River—1141 to 864 km and three tributaries along this waterway. Two samplesof deep sediments were used for comparison. The results indicate the significant upward enrichment of Zn, Sb, Cr, Nd, and Dy insediments belongs to the Iron Gate Reservoir. The sample 4-Smed is labelled as a hot spot of contamination with Zn, Cr, As, Sb,Nd, and Dy. Also, a trend of increasing concentration in the time period from 1995 to 2016 was found for elements Zn, Cr, and Niin sediment samples in the Iron Gate Reservoir. Chemometric analysis shows the grouping of sample sites into clusters charac-terized by the following properties: (i) increased concentration of all measured elements (samples within the Iron Gate Reservoir);(ii) increased Cu concentration (11-Pek); and (iii) lower concentrations of the measured elements (deep sediments). The datapresented hereby contribute to the monitoring of pollution of the River Danube sediments and give the first view of Ln profile inthe studied sediments

Instrumental neutron activation for analysis of spatial distribution of heavy metals in surface sediments of the Danube River

In this paper, the spatial distribution of the heavy metals including technology-critical elements (TCE) in the surface river sediments was investigated. The surface sediments of the Danube River in the Republic of Serbia, as well as three tributaries were analysed. Instrumental neutron activation analysis (INNA) has been applied for quantification of the selected element in the samples. The main featues of INAA are: simultaneously determining more than 40 elements with high sensitivity and low detection limit, high selectivity due to specific nuclear reaction for each element, the nondestructive method, the sample stays intact and no chemical separation treatment is involved, simple sample preparation step, especially solid samples, a small quantity of sample (≈ 200 μg) and determination of the total element concentration independent of chemical species, real total analysis since the test portion does not have to be dissolved. The heavy metal concentration in the sediments connected with hydropower dam and accumulation of sediments in the reservoir systems Iron gate I and Iron gate II were discussed. Surface river sediments were collected from the river bottom at the central and the deepest part using an Ekman grab sampler and air-dried in a thin layer in the dark at room temperature (23 ± 1 °C). Also, deep river sediments (1.5 and 7 m) were collected and used for comparison purpose. After drying, the samples were homogenized using a pestle and mortar and sieved through a 1-mm sieve to ensure sample homogeneity. INAA were used to quantify following elements: Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Ga, As, Se, Yr, Ag, Cd, Sb, La, Ce. Nd, Sm, Eu, Gd, Tb, Dy, Tm, Yb, Th, Hf, Ta, W, Au, Hg and U. Irradiations were performed at the pulsed reactor IBR 2 (Frank Laboratory of Neutron Physics, JINR, Dubna, Russian Federation) using epithermal neutrons. Principal Component Analysis (PCA) and Power transformation as a pretreatment method were applied for analysis of experimental data. It was found that the increase in the amount of sediment in the reservoir prior to the dam Iron gate I was accompanied by an increase in the concentration of the following metals: antimony, arsenic, chromium, europium, neodymium and samarium.VII International Conference on Radiation in Various Fields of Research : RAD 2019 : book of abstracts; June 10-14, 2019; Herceg Novi, Montenegr

On the Geochemistry of the Danube River Sediments (Serbian Sector)

To determine the nature and origin of the unconsolidated bottom sediments, as well as to demonstrate and quantify the presence of Presumably Contaminating Elements (PCE) in the Serbian Danube River, as a novelty, the mass fractions on nine major elements as oxides—SiO2, TiO2, Al2O3, FeO, MnO, MgO, CaO, Na2O, and K2O, as well as Sc, V, Cr, Co, Ni, Cu, Zn, As, Rb, Sr, Zr, Sb, Cs, Ba, La, Hf, Ta, W, Th, and U were determined by Instrumental Neutron Activation Analysis (INAA) in 13 sediment samples collected between Belgrade and Iron Gate 2 dam. INAA was chosen for its ability to perform elemental analysis without any preliminary sample treatment that could introduce systematic errors. The distribution of major elements was relatively uniform, with the sampling locations having less influence. Concerning the trace elements, excepting the PCE Cr, Ni, Cu, Zn, As, and Sb, their distributions presented the same remarkable similarity to the Upper Continental Crust (UCC), North American Shale Composite (NASC), Average Bottom Load (ABL), and Average Dobrogea Loess (AVL), and were in good concordance with the location of the Serbian Danube River in the Pannonian Plain. In the case of considered PCE, both Enrichment Factor and Pollution Load Index showed values higher than the pollution threshold, which pointed towards a significant anthropogenic contamination, and rising concern to what extent the water quality and biota could be affected