Natural and anthropogenic sources of chromium, nickel and cobalt in soils impacted by agricultural and industrial activity (Vojvodina, Serbia).

This study reports the contents and sources of chromium, nickel and cobalt, as well as Al, Ca, Mg, K, Fe and Mn in Vojvodina regions Srem and Central Banat area soil samples. Different methods were applied to identify the sources of the studied elements and to classify the latter as geogenic and/or anthropogenic: modified Tessier sequential extraction, calculation ratio of E/Al, XRPD, correlations and cluster analysis. The sampling methodology was according to the GEMAS project. The results show that increasing content of chromium, cobalt and nickel detected in studied soils can be explained by a distribution pattern and the presence of ultramafic and mafic parent rocks, as well as by significant anthropogenic pollution, mainly originating from the industry at some localities. The statistically significant difference between the content of Cr and Ni in soils of Srem and C. Banat is observed. The content of the studied elements is higher in soils of Srem. The normalization to Al indicating a presence of the anthropogenic sources which my significantly affect the content of Cr and Ni in the soils from Beocin, Ruma and Stara Pazova. There is no shown influence of eventual agrochemicals application on the Cr, Ni and Co content.

Assessment of arsenic and mercury contamination in the Tisa River sediments and industrial canal sediments (Danube alluvial formation), Serbia.

The purpose of this study was to examine the levels of As and Hg and mobility of these contaminants in the sediments of the River Tisa and canal sediments (alluvial formation of the Danube River, Serbia), in order to determine the degree to which the ecosystem is harmed by these pollutants. The sequential extraction procedure (modified Tessier method) was used to extract the metals from the sediments. Arsenic is extracted in the second, third and fifth fraction, with dominant extraction in the second fraction. This distribution indicates that As is significantly present in the form of carbonates, whereas the part of As is present in the form of oxides. The most important extraction of Hg is in the fifth stage (extraction with 6M HCl), with over 80 % of extracted element in both types of sediment, indicating a strong association between Hg and Fe crystalline oxides as well as presence of Hg in the form of sulfides. Based on arsenic and mercury content in sediments and results of sequential extraction it can be concluded that on the studied localities there is no significant As and Hg contamination.

Evaluation of heavy metal contamination in sediments using the method of total digestion and determination of the binding forms-Tisa River Basin, Serbia.

This paper describes an approach for the evaluation of metal contamination in sediment, using the determination of binding forms of elements (sequential extraction method), the total element content (digestion method), as well as a comparison of the obtained results with the legislative limits of the EU. Results indicate that silicates are significant substrates for Ni and Cr, whereas Zn, Cd, Pb, and Cu were not dominantly bound to silicates. Mg is present in the form of carbonates and silicates; Fe is in the form of oxides, and Mn is in the form of Mn carbonate and oxides. Zn, Cd, and Cu are dominantly extracted in the labile fractions and because of this they are likely to pose a direct and significant threat to the environment. The results of a comparison with the legislative limits of the EU indicated that in some of the sediments, elevated levels of Zn, Cd, and Cu exist. The contamination was caused by permanent pollution, originating mainly from industrial activities, municipal sewage discharge and agriculture. Results indicate to the significance of the employment both of methods, sequential extraction and total digestion, for metal investigation in sediment. With the aim of protecting the sediment quality of the Tisa River, of importance for Central Europe, the obtained results also indicate the necessity for systematic investigations in all countries through which this river flows.

Trace elements as tracers of environmental pollution in the canal sediments (alluvial formation of the Danube River, Serbia).

The purpose of this study was to examine the levels of trace elements and to discuss the origin and mobility of these contaminants in the canal sediments (alluvial formation of the Danube River). The most significant fractions binding all of the studied elements were oxides and silicates. The high proportion of elements in the residual fraction and the generally low contents of extractable elements reflected the background geochemical conditions. The contents of trace elements (except Hg and As) were dominantly controlled by the presence of Fe and Mn oxides as well as by the grain size and the geochemical composition of the sediment. The studied alluvial sediments were not heavily contaminated; there were only few sites where an anthropogenic influence on the concentrations of some metals (Cu, Cd, Zn, and Pb) was noticed. The results from this study show that impact of Pancevo industrial zone on the quality of the Danube River and its contamination with trace element is minor.

Assessment of heavy metal pollutants accumulation in the Tisza river sediments.

In this study we have worked on the evaluation of heavy metal contamination in the sediments taken from the Tisza River and its tributaries, and thereby used the sequential extraction method, geochemical normalization, the calculation of the enrichment factor (EF), and the methods of statistical analysis. The chemical fractionation of Ni, Cu, Zn, Cr, Pb, Fe, and Mn, carried out by using the modified Tessier method, points to different substrates and binding mechanisms of Cu, Zn and Pb in sediments of the tributaries and sediments of the Tisza River. The similarities in the distributions of Fe and Ni in all types of sediments are the result of geochemical similarity as well as of the fact that natural sources mainly affect the concentration levels of these elements. The calculated enrichment factors (EF, measured metal vs. background concentrations) indicated that metal contamination (Cu, Pb, Zn and Cr) was recorded in the sediments of the Tisza River, while no indications of pollution were detected in the tributaries of the Tisza River and the surrounding pools. The maximum values of the EF were close to 6 for Cu and Pb (moderately severe enrichment) and close to 4.5 for Zn (indicating moderate enrichment). It can be said that the Tisza River is slightly to moderately severely polluted with Cu, Zn, and Pb, and minorly polluted with Cr. It is concluded that sediments of the Tisza serve as a repository for heavy metal accumulation from adjacent urban and industrial areas.