Ivan Anđelković

Aqua regia extracted metals in sediments from the industrial area and surroundings of Pančevo, Serbia.

Surface and buried sediments were analyzed for Ba, Ca, Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn and V, as well as for total carbon and hydrogen to assess the distribution of sediment pollution due to the vicinity of the petrochemical complex. The samples, collected from 20 locations within the petrochemical complex and from 16 locations outside the complex, were aqua regia extracted and analyzed by ICP/OES. Metals were determined with an acceptable accuracy for certified metals of 82-113%. The precision for the aqua regia extraction was satisfactory, less than 20%, except for Cd where it was 28%. Comparison of the data from the petrochemical with those from the non-petrochemical areas showed different distributions of the metals. Metals that exceeded the baseline range; Ba, Cd, Cu, Zn and Pb, were detected in higher concentrations in sediments that were under the influence of the chlor-alkali plant within the petrochemical complex. Comparison with data from the petrochemical complex and its surroundings and their distribution demonstrated that the metal compositions of the sediments were modified by anthropogenic activities.

Evaluation of sediment contamination with heavy metals: the importance of determining appropriate background content and suitable element for normalization

In the present study, concentrations of heavy metals (Cd, Cu, Co, Mn, Cr, Ni, Pb, and Zn) were determined at 35 river sediments in Serbia. The anthropogenic heavy metals input and quantification of the metal enrichment degree in sediments were estimated by calculating geo-accumulation indices (Igeo) and enrichment factors (EF). These pollution indices have been calculated using different background values (continental crust and local background values) and different element used for normalization (Al and Fe), followed by result comparison. The EF values calculated with continental crust as background (minor to extremely severe enrichment) were higher than when regional background values were used (minor to moderate enrichment). Significant influence of background values on the Igeo values is observed. Values of geo-accumulation index (<2) revealed that studied river sediments are remaining unpolluted to moderately polluted with Co, Mn, Cr, and Ni. Significant pollution in the sediments was observed for Cd, Cu, Pb, and Zn elements. The results of this study confirm the relevance of precise and accurate determining of local background concentrations while assessing sediment pollution. The values of EFs for studied elements were more influenced by the choice of background values than selection of element used for normalization. Our recommendation would be to use the local and regional background content in quantification of metal contamination in sediments, since these values differ and are site and region dependent.

Risk assessment of trace element contamination in river sediments in Serbia using pollution indices and statistical methods: a pilot study

To effectively manage potential environmental and human health impacts of contaminated river sediments, it is important that information about the source (anthropogenic vs geogenic), variability and environmental risks associated with the contamination are well understood. The present study was carried out to assess the source and severity of contamination and to undertake a risk assessment for selected elements (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn) in river sediments in Serbia. The estimate of the anthropogenic component of contamination was derived by determining the total element content and the background values for elements in sediments, and the severity of pollution was assessed by calculating a number of pollution indices including the contamination factor, the enrichment factor, the index of geoaccumulation, the ecological risk factor, the potential ecological risk index, the pollution load index, the combined pollution index, the modified degree of contamination and the toxic unit factor. This analysis indicates that river sediments in Serbia are primarily polluted with Zn, Cu and Cd. The most contaminated river systems are the Ibar, Pek, West Morava and Great Morava rivers. Mining activities were found to have a significant influence on sediment. Multivariate analyses suggested anthropogenic origins for Pb, Zn, Cd, As, Ni and Cu, whilst Fe, V, Mn, Co and Cr appear to have a mixed origin (both lithogenic and anthropogenic sources). A geochemical approach, with a calculation of pollution indices and statistical methods, is recognised as useful for the risk management of trace elements in sediments around the world.

Investigation of mechanism and critical parameters for removal of arsenic from water using Zr–TiO2 composite

ABSTRACT Using the microwave-hydrothermal method for the synthesis of composite, high surface density of hydroxyl groups, as an active adsorption sites for arsenic, was obtained. Adsorption mechanisms of As(III) and As(V) onto zirconium-doped titanium dioxide (Zr–TiO2) were investigated and proposed using macroscopic and microscopic methods. Obtained results are suggesting inner-sphere and outer-sphere adsorption mechanisms for As(III) and As(V), respectively. This allowed us to identify parameters that are critical for the successful removal of arsenic from water, which is essential information for further optimization of the removal process. The composite was further applied for the removal of As(III) and As(V) from water in a dynamic flow through the reactor. Column study proved that the removal of both arsenic species below the value recommended by WHO can be achieved. Elution of As(III) and As(V) from the composite can be done by using small amounts of 0.01 M NaOH solution resulting in preconcentration of arsenic species and possible multiple usage of composite.

Size-segregated trace elements in continental suburban aerosols: seasonal variation and estimation of local, regional, and remote emission sources

We have measured trace element contents in suburban aerosols from six size fractions in the range of PM0.27–16 from a background station in Belgrade (Serbia). The distribution and concentration of elements were determined within each of the investigated Dp fractions with emphasis on the fine and coarse modes. Fine/coarse mode ratios of element can provide information regarding their anthropogenic or natural origin. Analysis of seasonal variations of element contents in fine and coarse mode show that Cd, Co, K, and V have higher concentrations in the fine mode during heating season, while Fe contents are lower. In the coarse mode, Cu and V have higher concentrations during the heating season, while Al, Fe, Mg, Mn, and Sb contents are lower. We also apply a distribution probability model (normal, log-normal, and three-parameter Weibull) as new approach to estimate the distances of emission sources that can contribute to pollutant contents in particulate matter of the investigated location.