Spatial pattern of recent rainfall trends in Serbia (1961–2009)

This paper examines a spatial pattern of annual, seasonal and monthly rainfall trends in Serbia. The study used data from 63 weather stations between the period of 1961–2009. The rainfall series was examined by applying the nonparametric method of the Mann–Kendall test and Sen’s method to determine the significance and magnitude of the trends. Significant trends have not been detected for the whole country at an annual scale. Seasonal trends at the confidence level of 97.5 %, however, indicate a slight decrease in winter (5 stations out of 63) and spring (7 stations out of 63) precipitation and an increase in autumn precipitation (10 stations out of 63). Results for monthly rainfall trends also generally showed a nonsignificant trend with the exception of a negative trend in May (6 stations out of 63) and positive trend for October (9 stations out of 63). Calculated global autocorrelation statistics (Moran’s I) indicate a random spatial pattern of rainfall trends on annual, seasonal and monthly timescales with exceptions for March, June and November. Overall, results suggest that only weak, mostly nonsignificant trends are present in Serbia in the period 1961–2009.     

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.     

Determination of O3, NO2, SO2, CO and PM10 measured in Belgrade urban area

O(3), NO(2), SO(2), CO and PM(10) concentrations, simultaneously determined for the first time in Belgrade urban area in the autumnal period of 2005, are presented. The obtained results display similar behaviour of SO(2), NO(2), CO, PM(10) opposite from that of O(3). The weekend effect was also investigated showing diminution of average daily concentrations of SO(2), NO(2), PM(10) and CO for 72, 40, 37 and 42% respectively, and increase of the average daily concentration of O(3) for 56%. Influence of meteorological conditions on observed concentration levels was studied, too. The observed influence of wind speed on the O(3) nightly concentration levels was analyzed pointing to the phenomena of O(3) transport during episodic measurements. To make an identification of possible pollution sources and analyse the influence of meteorological parameters on pollution levels, air back trajectories for high level concentrations episodes were calculated and analysed. A multivariate receptor modelling (Principal Component Analysis, Cluster Analysis) has been applied to a set of data in order to determine the contribution of different sources. It was found that the main principal components, extracted from the air pollution data, were related to gasoline combustion, oil combustion and ozone transport.     

n-Octyl esters of long-chain fatty acids are not anthropogenic pollution markers

n-Octyl esters of higher fatty acids have been reported as markers of urban wastewater in sediments, polychaeta, fish, crabs and oysters (Chaler et al. in J Chromatogr A 1046:203–210, 2004)). However, up to date, there were no subsequent studies to confirm this claim. Likewise, Chaler and co-workers did not consider that the mentioned compounds might occur naturally in the environment. Here we found seven n-octyl straight-chain alkanoates, from C-20 to C-26, in the wild-growing plant Heracleum sphondylium L., Apiaceae, from 14 locations. Those plant metabolites were unambiguously identified by gas chromatographic co-injection of the synthesized esters with the inflorescence washings. All identified octyl esters represent new natural compounds, except for octyl docosanoate. Since we have demonstrated that n-octyl esters occur naturally, and in abundance, they cannot be recognized any longer as wastewater markers. Additionally, here we provide evidences that the compounds identified by Chaler et al. (2004) are in fact 2-ethylhexyl esters, mistakenly identified as n-octyl esters.     

Multidimensional Approaches to Calculation of Design Floods at Confluences—PROIL Model and Copulas

Environmental Modeling & Assessment - In confluence areas, where river flow slowdowns can be substantial, the selection of design flows for the purpose of designing a flood control system...     

Measurement and evaluation of the environmental noise levels in the urban areas of the city of Nis (Serbia)

The environmental noise level represents one of the key factors of life quality in urban areas of modern cities. A continuous monitoring of the noise levels and the analysis of results have become a necessity when we discuss a possible recovery of those areas with high levels of noise pollution, and particularly, those zones which were designed for specific activities, e.g., areas around hospitals and schools. The city of Nis, Serbia, owing to the permanent long-term noise monitoring, possesses a database containing figures related to the noise levels at relevant locations in the city, which can serve as a basis for an analysis of the change of conditions, their tendencies in the future, and recognizing factors which influence the danger of noise pollution. The paper involves an analysis of the environmental noise level collected during the previous years.     

Cadmium and mercury accumulation in European hare (Lepus europaeus): age-dependent relationships in renal and hepatic tissue

A total of 63 European hares have been collected from five Serbian agricultural regions. The hares assayed were divided into four age groups (3–6 months, 12 months, 12–24 months, and 24–36 months) and investigated upon presence at cadmium (Cd) and mercury (Hg) in the kidney and liver. The positive significant correlation (Ps—Pearson’s coefficient) between Cd concentrations in the kidney and liver within age group the 3–6 months was found (Ps?=?0.81, p?p?p?>?0.05). Statistically significant differences were registered between Hg content in the liver of the hares aged 24–36 and 12 months (p?p?>?0.05). The strong statistically significant associations were registered between Cd and Hg content in the liver (Cd L/Hg L) in the age group 3–6 and 12–24 months (Cd L/Hg L, Ps?=?0.94; p?Ps?=?0.91; p?相似文献   

Determination of toxic elements in meat products from Serbia packaged in tinplate cans

Environmental Science and Pollution Research - This work aimed to examine the influence of the storage period on the content of toxic elements (As, Cd, Hg, and Pb) in five types of canned meat...     

Modelling of dissolved oxygen content using artificial neural networks: Danube River, North Serbia, case study

The aims of this study are to create an artificial neural network (ANN) model using non-specific water quality parameters and to examine the accuracy of three different ANN architectures: General Regression Neural Network (GRNN), Backpropagation Neural Network (BPNN) and Recurrent Neural Network (RNN), for prediction of dissolved oxygen (DO) concentration in the Danube River. The neural network model has been developed using measured data collected from the Bezdan monitoring station on the Danube River. The input variables used for the ANN model are water flow, temperature, pH and electrical conductivity. The model was trained and validated using available data from 2004 to 2008 and tested using the data from 2009. The order of performance for the created architectures based on their comparison with the test data is RNN > GRNN > BPNN. The ANN results are compared with multiple linear regression (MLR) model using multiple statistical indicators. The comparison of the RNN model with the MLR model indicates that the RNN model performs much better, since all predictions of the RNN model for the test data were within the error of less than ±10 %. In case of the MLR, only 55 % of predictions were within the error of less than ±10 %. The developed RNN model can be used as a tool for the prediction of DO in river waters.