Ecological and Health Risks Attributed to Rare Earth Elements in Coal Fly Ash.

The occurrence and distribution of yttrium and rare earth elements (REYs), along with major elements and heavy metal(loid)s (HMs) in coal fly ash (CFA) from five coal-fired power plants (CFPPs), were analyzed, and the REY-associated ecological and health risks were assessed. The individual REYs in CFA were abundant in the following order: Ce > La > Nd > Y > Pr > Gd > Sm > Dy > Er > Yb > Eu > Ho > Tb > Tm > Lu. The total REY content ranged from 135 to 362 mg/kg, averaging 302 mg/kg. The mean light-to-heavy REY ratio was 4.1, indicating prevalent light REY enrichment in CFA. Significantly positive correlations between the REYs suggested that they coexist and share similar origins in CFA. REYs were estimated to pose low to moderate ecological risks, with risk index (RI) values ranging from 66 to 245. The hazard index (HI) and target cancer risk (TCR) of REYs from CFA, estimated to be higher for children (HIc = 0.15, TCRc = 8.4 × 10-16) than for adults (HIa = 0.017, TCRa = 3.6 × 10-16), were well below the safety limits (HI = 1, TCR = 1.0 × 10-6). However, the danger to human health posed by HMs in the same CFA samples (HIc = 5.74, TCRc = 2.6 × 10-4, TCRa = 1.1 × 10-4) exceeded the safe thresholds (excl. HIa = 0.63). The mean RI and HI attributed to REYs in CFA were 14% and 2.6%, respectively, of the total risks that include HMs.

Acetamiprid's degradation products and mechanism: Part II - Inert atmosphere and charge storage.

Reuse and/or recycling of spent adsorbents is taking a central role in modern thinking and catalyzed carbonization is the way forward. Herein we explore the carbonization of adsorbed acetamiprid, in an inert atmosphere, as a way of recycling and producing nitrogen-rich carbon material for potential use in supercapacitors. Added value material and the reuse of the adsorbent were achieved by carbonization at 700 °C under argon. The formation of a nitrogen-doped carbon layer as an active material on the adsorbent, bonded through a C-Si linkage, has been conclusively verified through elemental composition quantification using XPS and EDX measurements. Two-stage catalytic decomposition and condensation of the adsorbed pesticide is followed by TGA and TPD-MS. Attained carbon-based materials give stable Faradaic capacitance with a slight dependency on the number of adsorbing cycles. Capacitance calculated with respect to the adlayer carbon material reaches values as high as 610 F g-1. Galvanostatic Charge/Discharge measurement confirmed the stability of explored materials with a slight increase in capacitance over 1000 cycles. The presented results envisage electroactive materials preparation from environmental pollutants, adding value to spent adsorbents.

Prediction of Drug Stability Using Deep Learning Approach: Case Study of Esomeprazole 40 mg Freeze-Dried Powder for Solution.

A critical step in the production of Esomeprazole powder for solution is a period between the filling process and lyophilization, where all vials, partially closed, are completely exposed to environmental influences. Excessive instability reflects in pH value variations caused by oxygen's impact. In order to provide pH control, which consequently affects drug stability, Esomeprazole batches, produced in the same way, were kept in partially closed vials for 3 h at temperatures of 20 °C and -30 °C, after which they were lyophilized and stored for long-term stability for 36 months. The aim of the presented study was to apply a deep-learning algorithm for the prediction of the Esomeprazole stability profile and to determine the pH limit for the reconstituted solution of the final freeze-dried product that would assure a quality product profile over a storage period of 36 months. Multilayer perceptron (MLP) as a deep learning tool, with four layers, was used. The pH value of Esomeprazole solution and time of storage (months) were inputs for the network, while Esomeprazole assay and four main impurities were outputs of the network. In order to keep all related substances and Esomeprazole assay in accordance with specifications for the whole shelf life, the pH value for the reconstituted finish product should be set in the range of 10.4-10.6.

Distribution of polyphenolic and sugar compounds in different buckwheat plant parts.

The aim of this study was to provide information on the phenolic and sugar profiles of different parts of the buckwheat plant, which can define that buckwheat is a functional food, with a high nutritional value and very useful for human health. Therefore, the extracts of buckwheat leaf, stem, and flower, as well as buckwheat grain were analysed for the content of polyphenol and antioxidant tests. The identification of a notable number of phenolic compounds and quantification of sugars in different parts of buckwheat indicates that buckwheat is a highly valuable plant. A total of 60 phenolic compounds were identified (18 cinnamic acid derivatives, 14 flavonols, 13 flavan-3-ols (including proanthocyanidins), 10 hydroxybenzoic acid derivatives, and 5 flavones) using ultra-high-performance liquid chromatography (UHPLC), coupled with a hybrid mass spectrometer which combines the Linear Trap Quadrupole (LTQ) and OrbiTrap mass analyzer. The highest number of phenolic compounds was found in the analysed buckwheat flower sample, and then in the leaf, followed by the grain and the stem. In addition, the sugar profile of buckwheat leaf, stem, flower and grain, as well as the buckwheat pollen and the nectar was analysed. Hence, 16 sugars and 5 sugar alcohols were detected by the high-performance anion exchange chromatography (HPAEC) with a pulsed amperometric detector (PAD). Sucrose was found in a significant amount with the highest content in buckwheat leaf. Trisaccharides had similar accumulation in the sample extracts, while disaccharides dominated in buckwheat leaf, followed by nectar and pollen. The sugar alcohols showed the highest content in buckwheat grain, where erythritol was predominant. The obtained results show that buckwheat is very rich in phenolic compounds and sugars. In addition to grain, the other parts of the buckwheat plant can be used as a very good source of different classes of phenolic compounds. This study provides useful information on the distribution of phytochemicals in different parts of the buckwheat plant, which contribute to the maintaining of the status of buckwheat as a functional food.

Characterization of PM2.5 sources in a Belgrade suburban area: a multi-scale receptor-oriented approach.

Designated as the most harmful for health, PM2.5 aerosol fraction was a subject of our study. It was collected for all four seasons during 2014/15 in the suburban area of Belgrade (Serbia) and analysed for Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, As, Ba and Pb elements and for NH4+, NO3- and SO42- ions by particle-induced X-ray emission and ion chromatography techniques, respectively. Obtained concentrations have been treated by a combination of several receptor-oriented models to reveal source contributions to the suburban PM2.5 at different spatial scales. Applied positive matrix factorization analysis indicated five main groups of emission sources: biomass burning (14.5%), traffic (3.9%), regional combustion/secondary sulphates (28.8%), local combustion/secondary nitrates (29.7%) and soil (5.4%). Local heating units had been pointed out as dominant contributors by long-range transport and ground-wind circulation analyses. Air masses circulating over the Balkan Peninsula denoted regional emissions as responsible for the high concentrations of secondary sulphates. Local and long-range transport analyses combined suggested that the BB and the LC/NO3 originated from the wider urban area. Several Saharan dust episodes were detected as well. Presented results might be a basis for the development of air pollution mitigation strategies in the continental Balkan area, considered one of the most polluted and under-investigated European regions.

Polyphenol profile of buckwheat honey, nectar and pollen.

A focus of research in recent years is the comparison of honey as the final product of bees with pollen and nectar of the plant from which the honey originates, as the main food source for bees. Buckwheat honey is recognized as a nutritionally valuable product, which provides a scientifically proven health benefit and is confirmed as a functional food. The quality of this type of honey is attributed to high levels of phytochemicals in buckwheat. The purpose of this study was the examination of similarity between buckwheat honey and buckwheat nectar and pollen, as well as simultaneous investigation of their chemical profiles and the origin of the honey. The phenolic profile of buckwheat pollen showed a lower number of flavonoids and phenolic acids than those of nectar and honey samples, but confirmed the presence of the most characteristic polyphenols derived from the buckwheat plant. The notable difference was found to be the presence of (epi)catechin units, its galloylated derivatives and procyanidin dimers, which were not present in honey. Honey polyphenols displayed a pronounced correlation with those of nectar, but not with those of pollen. Finally, by comparing the polyphenolic profiles of honey, nectar and pollen sharing the same geographical origin, new data could be provided for a potential assessment of the botanical origin of buckwheat honey.

Physicochemical analysis and phenolic profile of polyfloral and honeydew honey from Montenegro.

The research subject of this paper was a detail physicochemical analysis of 28 honey samples from the northern part of Montenegro. The honey from Montenegro has not been previously studied in such detail. Differentiation between samples, such as honeydew honey and polyfloral honey, was based on electrical conductivity, which was higher than 0.8 mS cm-1 for honeydew honey, as was expected. Other investigated physicochemical parameters (water content, free acids, diastase activity, hydroxymethylfurfural (HMF) content and sugar content) have shown great similarity for all honey samples. The main interest of this study was the identification and quantification of phenolic compounds using ultra-high performance liquid chromatography (UHPLC) with mass spectrometry detection. The results show that honey samples are very rich in phenolic compounds, especially quercetin. Among the 31 quantified phenolic compounds, the most dominant were phenolic acids. The highlight was based on p-hydroxybenzoic acid, p-coumaric acid, caffeic acid and ferulic acid. Considering polyphenolic compounds and sugar content, a high nutritional value can be observed in all samples, with an emphasis on polyfloral honeys, as was confirmed with principal component analysis (PCA). In addition, all honey samples were tested for total phenolic content (TPC) and radical scavenging activity (RSA). The results indicate the higher antioxidant ability of honeys from Montenegro in comparison to some honey samples from other countries in the region.

Tritium concentration analysis in atmospheric precipitation in Serbia.

Tritium activity concentration were monitored in monthly precipitation at five locations in Serbia (Meteorological Station of Belgrade at Zeleno Brdo, Vinca Institute of Nuclear Sciences, Smederevska Palanka, Kraljevo and Nis) over 2005, using electrolytic enrichment and liquid scintillation counting. The obtained concentrations ranged from 3.36 to 127.02 TU. The activity values obtained in samples collected at Zeleno Brdo were lower or close to the minimum detectable activity (MDA), which has a value of 3.36 TU. Significantly higher tritium levels were obtained in samples collected in Vinca Institute of Nuclear Sciences compared with samples from the other investigated locations. Amount of precipitation were also recorded. A good linear correlation (r = 0.75) for Zeleno Brdo and VINS between their tritium activity was obtained. It was found that the value of the symmetrical index n (which indicates the magnitude of tritium content changes with time (months) through its second derivative) is the highest for Vinca Institute of Nuclear Sciences compared to other locations, which is in accordance with the fact that the highest concentrations of tritium were obtained in the samples from the cited place.

Headspace solid phase microextraction method for determination of triazine and organophosphorus pesticides in soil.

A headspace solid phase microextraction method (HS-SPME) for simultaneous determination of five pesticides belonging to triazine and organophosphorus pesticide groups in soil samples was developed. Microextraction conditions, such as temperature, extraction time and sodium chloride (NaCl) content were investigated and optimized using 100 microm polydimethyl-siloxane (PDMS) fiber. Detection and quantification were done by gas chromatography-mass spectrometry (GC-MS). Relative standard deviation (RSD) and recovery values for multiple analysis of soil samples fortified at 30 microg kg(- 1) of each pesticide were below 13 % and higher than 70 %, respectively. Limits of detection (LOD) for all the compounds studied were less than 3.2 microg kg(- 1). The proposed method was applied in the analysis of some agricultural soil samples.