Due to its ability to accumulate metals, availability throughout the year and its large biomass, Phragmites australis (common reed) is suitable for biomonitoring studies for the evaluation of load level of water ecosystem with trace metals. The heavy metals concentration in P.australis tissue can be several ten to several thousand times higher than those in the surrounding water. In this study we examined the content of heavy metals (Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn, Sr and V) in sediment, water and different organs of Phragmites australis collected from Lake Skadar, Montenegro, during different seasons of the year 2011. The highest concentrations of Sr were found in the leaves, while the other studied metals showed their highest concentrations in the roots. Thus, P. australis is considered a root bioaccumulation species. For most metals the concentration in roots and stems increases over time until the end of the growing season, and then decreases, while the concentration in leaves increases even after the growing season of the plant. If P. australis is used for phytoremediation purposes, then it should be harvested after the growing season because then the concentration of metals in the aboveground parts is maximal
The aim of this study was to establish correlation of chemical composition and antioxidant activity of bilberry plants from Montenegro. Total phenolic, tannin, flavonoid, procyanidin and anthocyanin contents were determined in fruits and leaves extracts using spectrophotometric methods, while the measurements of metal content was carried out in an Inductively Coupled Atomic Emission Spectrometer. Qualitative and quantitative analyses of major phenolics were achieved by HPLC. In the investigated extracts, the most abundant phenolic was chlorogenic acid, followed by protocatechuic acid, while resveratrol, isoquercetin, quecetin and hyperoside were also present in significant quantities. Antioxidant potential was evaluated using two in vitro assays—FRAP and DPPH—being in the accordance with the cyclic voltammetry tests, performed as well. The results revealed that all the investigated extracts were rich in phenolic and essential mineral constituents, with significant antioxidant activity, depending on the polyphenolic and mineral contents, which was confirmed by principal component analysis.
Lacustrine systems are very complex water systems in terms of the transport of and interaction with heavy metals. Primarily due to its high variability and current chemical parameters, the tissue of macrophytes is a more plausible bio-indicator of the load level of metals within lake ecosystems than are water or sediment analyses. The macrophyte, Ceratophyllum demersum, sampled from the Skadar Lake in Montenegro was used as a bio-indicator. Sediments, water and plants were examined for their contents of ten metals in four different periods of 2011. The concentrations of the metals followed the trend: sediment > leaf C. demersum > stem C. demersum > water. There were differences in the sequences of the metal content in the plant compared to the sequences of their bioaccumulation ability. These differences suggest a different capacity of macrophytes for different metals. The accumulation of Mn was several times higher than the accumulation of the other analyzed metals. The highest ratio of leaf/stem concentrations was recorded for Mn (2.19) and the lowest was for Pb (1.04). The highest contents of Cd, Co, Cr, Pb, V and Sr were found in the tissues of C. demersum at the beginning of the growing season, whereas Ni, Zn, Cu and Mn were found at the end of the vegetative phase.
Arsenic is an ubiquitous element found in natural materials and in industrial products. The range of its concentrations found in the environment is large. Arsenic can occur in several oxidation states and is found in inorganic and organic forms. It is relatively mobile. The presence of arsenic in the environment, even at low levels, has negative effects on human and animal health. The investigation of arsenic content and behaviour in different type of waters and environment is important for chemistry and environmental protection. This paper represents a short review of scientific and expert investigations on the source, characteristics and distribution of arsenic in the environment.
The rate of both spontaneous and polarization assisted formation of oxide films on commercially grade titanium, DIN 3.7025, was studied in concentrated, 1–5M NaOH solutions, with particular attention to the early stages of oxide formation. Simultaneous chemical dissolution of oxides was considered.
The rate of spontaneous oxide formation was examined with cyclic voltammetry as an in‐situ method. The shape of potentiodynamic curves recorded in different alkaline solutions indicated that the electrolyte concentration affects the oxide composition.
Titanium electrodes were covered with oxide films of different thickness, and the time dependence of polarization resistance was measured under a fixed anodic polarization. The polarization resistance may either increase or decrease tending to attain a stationary value, which, for a fixed polarization, depends on both the initial thickness and the NaOH concentration.
In this paper the comparative analysis of different methods for the preparation and analysis of arsenic content in coal and coal ash have been presented. The suggested method is coal digestion method, i.e., coal ash digestion using the mixture of acids: nitric and sulphuric in presence of vanadium-pentoxide as catalyzer. The comparative analysis of different recording techniques (AAS-GH, AAS-GF and ICP-AES) has also been presented. For arsenic recording the suggested technique is AAS-GF technique. The obtained results show that the method of high precision, high sensitivity and high reproductivity has been obtained.
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