Bioavailability, Accumulation and Distribution of Toxic Metals (As, Cd, Ni and Pb) and Their Impact on Sinapis alba Plant Nutrient Metabolism

This study presents the behavior of white mustard seedlings Sinapis alba grown for three months in laboratory polluted soil containing As, Cd, Ni and Pb. Four different experiments were performed in which As was combined with the other three toxic metals in different combinations (As, AsCd, AsCdNi, AsCdNiPb), keeping the same concentrations of As and Cd in all tests and following the national soil quality regulations. The effects of these metals were monitored by the analytical control of metal concentrations in soil and plants, bioavailability tests of mobile metal fractions using three different extracting solutions (DTPA + TEA + CaCl2-DTPA, DTPA + CaCl2-CAT, and CH3COONH4 + EDTA-EDTA) and calculation of bioaccumulation and translocation factors. Additionally, micro, and macro-nutrients both in soil and plant (root, stem, leaves, flowers and seeds) were analyzed in order to evaluate the impact of toxic metals on plant nutrient metabolism. Metals were significantly and differently accumulated in the plant tissues, especially under AsCdNi and AsCdNiPb treatments. Significant differences (p < 0.05) in the concentration of both As and Cd were highlighted. Translocation could be influenced by the presence of other toxic metals, such as Cd, but also of essential metals, through the competition and antagonism processes existing in plant tissues. Significantly, more Cd and Ni levels were detected in leaves and flowers. Cd was also detected in seeds above the WHO limit, but the results are not statistically significant (p > 0.05). The extraction of metallic nutrients (Zn, Cu, Mn, Ni, Mg, K, Fe, Ca, Cr) in the plant was not influenced by the presence of toxic metal combinations, on the contrary, their translocation was more efficient in the aerial parts of the plants. No phytotoxic effects were recorded during the exposure period. The most efficient methods of metal extraction from soil were for As-CAT; Cd-all methods; Pb and Ni-DTPA. The Pearson correlations (r) between applied extraction methods and metal detection in plants showed positive correlations for all toxic metals as follows: As-CAT > DTPA > EDTA, Cd-DTPA > CAT > EDTA, Ni-EDTA = DTPA > CAT, Pb-EDTA = DTPA = CAT). The results revealed that Sinapis alba has a good ability to accumulate the most bioavailable metals Cd and Ni, to stabilize As at the root level and to block Pb in soil.

Analysis of cerium oxide by arc atomic emission spectrometry

Materials based on rare earth elements (REE) are of great importance due to their unique chemical and physical properties, but the effectiveness of their use depends on the quality of raw materials. Therefore, further development of the methods of analytical control in relation to rare-earth materials is aimed at increasing the accuracy and sensitivity of the methods, as well as at expanding the nomenclature and concentration range of the determined elements. Cerium oxide is used in glasses, ceramics, catalysts, phosphors, composite and scintillation materials, as well as in medicine. The problem of developing a new arc spectral method is extremely urgent to match modern requirements for the accuracy and sensitivity of the impurity determination for monitoring the purity of cerium oxide. A technique for arc atomic emission analysis of cerium oxide which meets modern requirements for the accuracy and sensitivity of the impurity determination has been developed. The range of impurities to be determined is significantly expanded compared to the standardized technique of the 1970s. The goal of this work is to study and develop a modern method for arc optical emission spectral analysis of cerium oxide using the instrumental capabilities of the atomic emission complex «Grand Globula». To specify compromise conditions for the determination of 15 REE impurities and 19 elements more, analytical lines were selected and the dependence of their intensity on the operating mode of the generator, the shape and size of the electrodes, the interelectrode distance, the ratio of the masses of the analyzed sample and graphite powder, as well as on the presence of various carriers (Ga2O3, NaCl, NaF, KCl, S, GeO) was analyzed. Application of the considered methodological approach to the selection of conditions made it possible to develop a method for spectral analysis of cerium oxide without preliminary dissolution of the sample with an extended range of determinable impurities. When studying the curves of the impurity evaporation, an exposure time was chosen to be sufficient for their complete evaporation (100 – 120 sec). The study has shown the 0promising character and feasibility of the developed arc spectral techniques applicable to the analysis of REE-based materials as an alternative to the methods for analysis of solutions. The metrological characteristics of the proposed procedure for the analysis of cerium oxide were evaluated in comparison with the standardized technique.

Good Practices of Quality Control in the Area Surrounding of Natural Mineral Water Abstraction of São Pedro Do Sul Medical Spa (Portugal)

São Pedro do Sul medical spa is a space with a millenary tradition in providing health services from the natural hot groundwater. The main source of supply of this thermal unit, was along the time, the Traditional Spring, which in the last decades has been controlled, and shows to have constancy in the flow rate, with about 10 L/s, with a temperature of 68.6°C in the origin. From 1999 onwards, with the construction of new abstraction, Well AC1, with 500m deep, with a maximum flow rate of 12.2 L/s, at 67°C, the exploitation potential of this resource increased. Due to the fabulous characteristics of the resource’s potential (hot natural mineral water), there has been over time a great development in the spa medical activity, having already frequented these spa 25450 users per year, reflecting a maximum annual turnover of 5.4 million euros, coming from thermalism alone. Currently, there are two Bathhouses in operation and the resource is used, not only for therapeutic and wellness thermalism but also for geothermal uses and yet in the cosmetic area. This situation becomes the perfect scenario for attracting investment, increasing the circulation of people and goods, but also in the interest of building new bathhouses, hotels and restaurants and subsequently new roads, gardens, public drinking water and sanitation networks. All this pressure causes a lot of potential damage to the environment, including the underground water environment, and could eventually lead to the closure of the medical spa, if the natural mineral water from the abstractions become contaminated. In Portugal, there are several legally imposed defensive mechanisms of the mineral aquifer system, namely the implementation of the Protection Perimeter, but also the analytical control of the natural mineral water, at the abstraction head, both in chemical and microbiological terms, in addition to the orientation to have an automatic, on-line, record system associated to the abstractions, monitoring parameters such as: water level, flow rate, temperature, pH and conductivity of the water captured. However, the Sao Pedro do Sul medical spa go further, implementing an external monitoring system, consisting of: i) double piezometers (to sample groundwater at different depths), ii) street rainwater samplers, and iii) records precipitation and respective quality. Thus, in this paper, after a brief presentation of the importance of the resource and the physical aspects of the place (geology, hydrogeology and quality of the resource), the fundamental elements of the implemented external monitoring system and its main results are presented, showing that precipitation itself is already contaminated, that street rainwater sample presents chemical elements that are highly harmful to public health, and that groundwater sometimes presents very worrying results. Finally, some actions are mentioned that have been implemented to minimize the potential for contamination of natural mineral water from abstractions and the mineral aquifer system.

Determination of the mineral composition of copper ores by X-Ray methods

One of the most difficult tasks of the analytical control of copper ores is the determination of the mineral forms of copper. Currently, for this purpose, iodometric and atomic absorption methods are used with preliminary leaching of various mineral forms. The disadvantage of those methods is a rather complicated sample preparation procedure and significant time of analysis. The most universal method for determining the mineral composition of solid samples is the X-ray diffraction method. However, significant variations in the phase composition of copper ores, overlapping reflections of different phases, the presence of an amorphous phase and structural defects necessitate the development of special approaches. In this work, the presence of an amorphous phase is taken into account by direct calculation of the mass fractions of crystalline phases by the G-factor method. The total copper content is determined by the X-ray fluorescence method. Methodological approaches based on using only X-ray methods are proposed, which exclude the procedures of leaching and dissolution of samples and provide determination of primary and secondary copper sulfides using calibration characteristics (3 min), and gaining data on the complete phase composition at the stage of routine analysis (10 – 15 min) and for research purposes (15 – 20 min).

Contribution of the generalized nonunique inverses to the minimum-energy control theory: The inverse model control investigation

The innovative analytical approach to the minimum-energy design problem of the inverse model control (IMC) state-space structures is presented in this work. Following the recent papers, it should be concluded that the optimal behavior of the IMC strategy cannot longer be associated with the application of the well-known Moore–Penrose minimum-norm inverse. However, the minimum-energy IMC-oriented scheme has only be obtained through heuristic methods. Nevertheless, in the recent authors’ work, it has been proven for the first time that such an issue can be considered in an analytical manner. Yet, the obtained results have only been valid for the second-order state-space systems. Therefore, the motivation instance proposed in the manuscript, confirming the possibility of extending such paradigm to higher-order plants, will certainly contribute to the introduction of the new unified minimum-energy IMC theory canon. Since the nonunique σ and H inverses can successfully be employed in the robustification of the discussed control strategy, they can also be helpful in the case of our essential considerations. Thus, from now on the yet unexplored research area can now be investigated in the analytical manner, what has never been seen before in the modern IMC-originated control theory and practice. The predefined methodology clearly fills the gap in the analytical control design procedures and opens a new chapter in the knowledge related to the well-known and broadly accepted multivariable control canons.

Food safety: modern methods of multicomponent determination of pesticides

Introduction. Analytical control of chemical contamination is essential in ensuring the safety of food products manufactured using pesticides. The development and testing of new methodological techniques for multicomponent measurement of the levels of residual amounts of biologically active ingredients are constantly in the field of view of analysts. Research objectives. To assess the suitability of the QuEChERS methodological approaches for the determination of a wide range of pesticides of various structures and physicochemical properties (up to 50 names of active substances) in food products and food raw materials of various compositions and origins (fruits, vegetables, cereals, rice, tea, coffee, milk, eggs and their derivatives, meat, offal). Material and methods. The measurements were carried out by tandem liquid chromatography-mass spectrometry and gas chromatography with a mass-selective detector, focused on screening and quantifying trace amounts of pesticides. The sample preparation procedure for analysis was carried out according to the QuEChERS method. Results. Multimethods have been created for the determination of residual amounts of pesticides in cereal grains (40 substances), fruits of vegetables and fruits (27 compounds), fruits of citrus crops (50 ingredients), 2,4-D acid in milk, eggs and by-products, fipronil and its toxic metabolite - sulfone in eggs, products of their processing (melange, dry egg white), muscle tissue and offal. The developments have supplemented the list of certified measurement methods included in the unified information fund of measurement methods of the Russian Federation. Conclusions. The unification of analytical methods for preparing samples of food products of various composition and origin for analysis, instrumentation of analytical laboratories with liquid and gas chromatography-mass spectrometry systems expand the possibilities of introducing group methods, ensure the readiness of testing centres to perform multi-purpose tests to identify and measure pesticide levels.

Methods gas chromatography, capillary electrophoresis, chromatography-mass spectrometry in analytical control of alcoholic beverages

Разработаны, внедрены в практику аналитического контроля и применены в научных исследованиях инструментальные экспрессные методики определения химического состава продуктов, полупродуктов и отходов спиртового и ликероводочного производства. Получены новые экспериментальные данные, и выявлены закономерности кинетики биотехнологических процессов. Developed, implemented in the practice of analytical control and applied in scientific research instrumental express methods for determining the chemical composition of products, intermediates and waste of alcohol and distillery production. New experimental data are obtained and the regularities of the kinetics of biotechnological processes are revealed.