Distribution and fractionation of heavy metals in the Tisa (Tisza) River sediments

Introduction In this work, sediments of the River Tisa (Tisza) are studied to assess their environmental pollution levels for some major heavy metals, as well as to predict the investigated elements’ mobility on the basis of their association type with the substrate. The Tisa River catchments area is a subbasin of the River Danube. Part of this river, 166 km long, belongs to the Serbian province of Vojvodina, before it flows into the Danube. It has been chosen for our investigation, because it has been exposed to intense pollution in the last decades. Materials and Methods The river sediment samples were collected at 32 locations. The proportions of sand, silt and clay fractions were determined. The sequential extraction procedure following a modified Tessier method was applied for speciation of the metal forms in the collected samples. The metal concentrations of Zn, Cd, Pb, Ni, Cu, Cr, Fe and Mn in extracts were determined by atomic absorption spectroscopy. Results and Discussion Granulometric analysis showed that some 50% of the Tisa River sediments were silt and clay, while the rest was sand with quartz, as the main constituent. The average metal content of the surface river sediment samples for every fraction of sequential extraction was presented and discussed in relation to pH, Eh and metal fractionation. The average metal content from the Tisa River sediments, obtained as an average of the metal’s concentration released in all five sequential extraction fractions was compared with: average metal contents of the Tisa River sediments in Hungary, metal content in soils formed on the Tisa River alluvium of Vojvodina, average metal content in soils of Vojvodina, and average metal content in soils of Hungary. An assessment of metal pollution levels in Tisa River sediments was made by comparing mean values for obtained results for the Tisa River sediments with the freshwater sediment’s Quality Guidelines as published by US EPA, Environment Canada and soil standards for Serbia. Conclusion According to US EPA and Canadian Quality Guidelines for freshwater sediments, the concentration of heavy metals in Tisa sediments were: (a) much higher than defined concentrations below which harmful effects on river biota are unlikely to be observed, (b) below defined concentrations above which harmful effects on river biota are likely to be observed. The concentration levels of Pb, Ni, Cu and Cr in Tisa River sediments are safe when compared with Serbian MAQ (Maximum Allowed Quantity) standards for soils, but they are unsafe in the case of Zn and Cd. Recommendations and Outlook The quality of sediments in the Tisa River was on the border line between potentially polluted and polluted. This line could very easily be exceeded since the quality of sediments in the Tisa River in Hungary was already worse than in Serbia. These results indicated the need for further monitoring of heavy metals in that locality.     

Levels of PAHs in the soils of Belgrade and its environs

Polycyclic aromatic hydrocarbons (PAHs) were analysed in 39 soil samples (0–10 cm upper layer) collected in Belgrade, the capital of Serbia. The sampling sites were randomly selected from urban, urban/recreational and rural areas; the samples were collected in April and December 2003 and July and October 2004. The sum of the 16 PAHs corresponding to the recreational zone (298 μg/kg) was close to the urban zone (375 μg/kg). Mean soil ΣPAH concentration from rural areas was 18 μg/kg dry weight. Comparing to values observed in the urbanized locations around the world, the overall levels of PAHs in this study are low. The PAH ratios obtained pointed to a domination of pyrogenically formed PAHs in the examined soils. The dominant PAHs in soil samples in urban zones were fluoranthene, benz[a]anthracene, phenanthrene and pyrene, mostly emitted from noncatalyst vehicles which are still in use in Serbia. The total carcinogenic potency for each sampling site was calculated. Regardless of the used carcinogenic activity factors, carcinogenic potency of 7 sites were 3–9 times higher than the reference ones indicating the increased carcinogenic burden of soils from these sites.     

流动注射分光光度法在线分析水中总铁

采用流动注射邻菲哕啉分光光度法在线分析水中总铁,考察了显色剂、消解液、酸度、反应盘管长度、载流流量、注样体积、采样时间等因素对试验的影响。方法在0.100mg／L-10.0mg／L范围内线性良好,检出限为0.04mg／L,实际水样平行测定的RSD≤3.7％,加标回收率为95.0％-96.0％。     

Distribution of heavy elements in urban and rural surface soils: the Novi Sad city and the surrounding settlements, Serbia

Concentrations of ten heavy elements (Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn), as well as the pH values, organic matter contents, and electrical conductivities were measured in the surface soil samples collected from 21 sites of urban areas in the city of Novi Sad, the second largest city in Serbia, its suburban settlement and the nearby villages. Range of the heavy element concentrations was from 0.16 mg/kg (for Hg) to 18,994 mg/kg (for Fe). Significantly higher Hg and Mn concentrations were observed in subgroups with rural and market garden samples in comparison to the subgroups with urban and grassland samples, respectively, while the contents of Pb found in the grasslands subgroup were significantly higher than in the subgroup with market garden soils. Only one sample of urban soil exceeded the maximum permissible value for Zn set by the relevant Serbian legislation. According to the Dutch soil quality standard, the Cd and Co concentrations in majority of the examined soils were higher than the target values for unpolluted soil. The content of Hg was above the target value in 52% of the samples, most of them belonging to the subgroup of market garden soils. The results for the Novi Sad city area were compared to the relevant data available for other cities in the Western Balkan Countries. Principal component analysis of data revealed seven outlying samples, while the rest of the analyzed samples were grouped together indicating similar heavy element patterns most probably due to mixed emission sources.     

Phytoplankton abundance and pigment biomarkers in the oligotrophic, eastern Adriatic estuary

Phytoplankton distribution and environmental characteristics were determined in a shallow, highly stratified and oligotrophic estuary (Zrmanja, eastern Adriatic). Samples were collected in two contrasting seasons; winter (February 2000), when river discharge was high, and in summer (July 2003), a period of drought. Phytoplankton distribution was closely related to salinity gradients, nutrient levels, and water residence time. Microscopic analysis revealed that phytoplankton was composed mainly of marine diatoms, dinoflagellates, cryptophytes, green flagellates, and coccolithophorids. The dominant biomarker pigments were fucoxanthin, alloxanthin and 19'-hexanoyloxyfucoxanthin, while lower, but indicative contributions of peridinin and chlorophyll b were also noted. Maximum abundance and biomass were found in the middle estuary in winter and in the upper estuary in summer. The estuary is mostly P-limited. Development of chain-forming marine diatoms was evident in winter. Due to the reduced nutrient input in summer, the biomass accumulated in the upper estuary (1,000 ng chlorophyll a l(-1)) was composed mostly of nanoplanktonic unicellular diatoms, nanoplanktonic marine dinoflagellates, cryptophytes, and chlorophytes. The concentrations of about 200 ng l(-1) hex-fuco, suggested that the contribution of prymnesiophytes to total biomass was comparable to that of diatoms and dinoflagellates. In the middle estuary and coastal sea, PO(4) and TIN were 3.5 times lower, resulting in a fivefold decrease in biomass (<100 ng chlorophyll a l(-1)). The oligotrophic Zrmanja and other karstic rivers discharging in the eastern Adriatic Sea, provide insufficient source of nutrients and low productivity of the eastern Adriatic Sea.     

Fractionation and potential mobility of trace metals in Danube alluvial aquifer within an industrialized zone

Thirty-five alluvial sediments of the River Danube and 12 groundwater samples were taken within the Pan?evo Oil Refinery (Serbia). The results for groundwater samples exceed European primary drinking water standards for Fe (obtained results, >200 μg/l) and Mn (obtained results, >50 μg/l), while the levels of the trace metals are below the thresholds for drinking water quality. Sediments were treated by sequential extraction procedure with five different solutions, each having a higher extraction capacity than the previous one. We also wanted to determine the possible relationships among trace metals and between sediment properties and elemental concentrations. These solutions partitioned metals into CH₃COONH₄ extractable (F1); HCl carbonate extractable and NH₂OH·HCl easily reducible (F2); (NH₄)₂C₂O₄/H₂C₂O₄ moderately reducible (F3); H₂O₂–HNO₃ organic/sulfide extractable fractions (F4); and HCl acid-soluble residue (F5). The sum of trace metals Ni, Pb, Cu, and Zn associated with the first two fractions (exchangeable, carbonate, and easily reducible) is significant and extremely important because it represents the proportion of heavy metals that can be easily remobilized by changes in environmental conditions such as pH, redox potential, salinity, etc. Sediments located nearer the groundwater flow are exposed to stronger groundwater fluctuation and had a higher quantity of amorphous and less stable substrates of trace metals. Principal component analysis was used to understand and visualize the associations between the trace metals and certain geological forms within analyzed sediments. The observed association between Cr with total sulfur and Mn from the acid-soluble residue could indicate that Cr is in the form of reduced, less toxic Cr(III), which is from the ecochemical point of view very important.     

Characteristics and origin of the hydrogen sulphide spring water from the Split spa (Southern Croatia)

The objective of this paper is to study the hydrological characteristics and origin of the hydrogen sulphide spring water from the Split spa in Southern Croatia in 1987, 1988 and 2003. This paper presents the results of monitoring the content of chlorides and hydrogen sulphide as well as the temperature of the hydrogen sulphide spring water. Since the hydrogen sulphide content during the dry periods significantly differs from the hydrogen sulphide content during rainy periods, this paper also compares the results obtained for those two periods. Under the influence of great quantities of rainfall during cold periods (winter and the beginning of spring) the ratio between seawater and surface water changes and thus the reduction of chlorides and other minerals occurs. The lowered temperature also reduces hydrogen sulphide which can disappear completely. The concentration of 12‰ chlorides (76–94.4% days/year) and 12 mg/L hydrogen sulphide (66.7–88.9% days/year) has been taken as a limit value between water with a normal typical content and water in cold rainy periods. According to the monitoring results it can be concluded that hydrogen sulphide spring water consists of seawater and hydrogencarbonate surface water with a fairly constant content during dry periods while the hydrogencarbonate content increases during rainy periods.     

Analysis of mosses and topsoils for detecting sources of heavy metal pollution: multivariate and enrichment factor analysis

In order to assess the contribution of emission sources to the pollution of areas remote from industrial facilities, a combined approach of enrichment factor analysis and multivariate statistics was used for detecting the origin of heavy metal pollution in the Zlatibor ecosystem, in Serbia. Samples of moss (Pleurozium schreberi, Hylocomium splendens, Scleropodium purum, Hypnum cupressiforme and Thuidum delicatulum) and of topsoil (0-5 cm) were collected in 2005. The concentrations of seven heavy metals (Cd, Cr, Cu, Mn, Ni, Pb and Zn) were determined in moss and soil samples by atomic absorption spectrometry. The results obtained by enrichment factor analysis and two multivariate statistical methods, principal component analysis and cluster analysis, enabled discrimination of the lithologic and anthropogenic sources of heavy metals in the mosses. Enrichment factors, calculated to evaluate the contribution to the metal content in moss from anthropogenic sources, revealed pollution of the investigated area by Cd and Pb, originating from long-range transport and fossil fuel burning.     

Trampling impact on vegetation of embryonic and stabilised sand dunes in Montenegro

Trampling is one of the human activities that are harmful for plant species and communities of sand dune ecosystems. The aim of this study was to compare the vegetation of embryonic and shifting Ammophila sand dunes with and without fencing to limit trampling. Fenced sand dunes appeared to be richer in species but differences were more prominent in embryonic sand dunes. Some species (Cakile maritima, Pancratium maritimum) were missing on trampled embryonic dunes. The positive impact of trampling exclusion on embryonic sand dunes was indicated by a lowered slope in a Whittaker graph as well as by rarefaction curves that showed higher species richness on the lower slope. Changes in the vegetation of more stabilised shifting Ammophila sand dunes due to trampling are not evident, although species composition is also impoverished. Fencing of parts of sand dunes proved to be an effective measure for vegetation conservation. In addition to physical exclusion of visitors, fences can also have symbolic value for raising public awareness.     

Sugar beet ( L.) growth reduction caused by hydrochar is related to nitrogen supply

Hydrothermal carbonization allows rapid conversion of biomass into a carbon-rich, lignite-like product (hydrochar). It is assumed to have beneficial effects on soil properties and plant growth, but detailed studies are lacking, especially in the field. The objective of our study was to investigate the effect of hydrochar incorporated into arable soils on soil mineral nitrogen (N) content and sugar beet growth. In 2010-2011, a field and a pot trial were conducted. Hydrochars (field: 10 Mg ha; pot: equivalent to 30 Mg ha) processed from sugar beet pulp (HSP) and beer draff (HBD) were tested against an untreated control. As a second factor, mineral nitrogen (N) fertilizer level (field: 0, 50, 100, 150 kg N ha; pot: 0, 100, 200 mg N kg soil) was varied. In both trials, hydrochars reduced initial sugar beet growth, especially when hydrochar with a high C/N ratio (38, HSP) was combined with a low N fertilizer level; high N supply partly compensated for the reduced seedling growth. Without N fertilization, no extractable N was present at the end of the pot trial in the HSP treatment, whereas in HBD even more N was extracted than in the control. This suggests remineralization of previously immobilized N when hydrochar with a low C/N ratio was applied (16, HBD). In the field, beet yield was equal at the high N fertilizer level in HSP and at all N levels in HBD treatment. Our results suggest that hydrochar can decrease plant-available N due to N immobilization. Other potential causes for the observed early growth reduction need to be studied more in detail.