Content Of Chemical Elements Research Articles

Monitoring the Level of the Air Contamination by Chemical Elements Impoundment in the Snow Melt of the Snow Blanket

The research on the snow blanket pollution in Chita and its environs has been conducted to determine 29 chemical elements in the snow melt. It has been revealed that there is a direct causality between the pollution degree of the snow aqueous phase and the level of air pollution in the technogenesis environment. While comparing some indicators of chemical elements content and their compounds in snow melt, a critical concentration in the reference sites has been identified. It has been noted that the standard ratios compliance for this phase in the conjoint backgrounds is not always realistic, requires the MPC indicators development for the snow under technogenic impact and consideration of natural geochemical conditions and climatic factors.

Plant-matrix reference materials as a tool for ensuring the uniformity of chemical measurements in geochemistry, ecology, agriculture and pharmacology

The population needs reliable information on the chemical composition of plants and products made from them in order to preserve the environment and its safety. With the increase in cross-border trade, there is a growing demand for traceable results of determining the content of chemical elements in plants and not only proteins, fats, carbohydrates, pesticides, moisture, vitamins, etc., which can affect the quality of human life. An urgent but difficult analytical task is to obtain reliable measurements of the elemental composition of agricultural and wild plants and various products made from them. Reference materials (RMs) are a widely recognized tool for ensuring the uniformity of chemical measurements. They are designed for certification (validation) of existing and new methods (techniques) of chemical analysis, certification studies in the development of reference materials, and professional testing of laboratories. The article lists the reputable manufacturers of plant RMs in which the content of chemical elements is certified. The ratio of certified, reference, and quality control samples of plant-matrix has been assessed. The classification of certified reference materials according to the type of plant material used for their food application is provided. The contribution of different countries to the development of plant CRMs is hown. The selection of plants for the development of new RMs is discussed from two points of view, namely food composition databases (AOAC INTERNATIONAL) and the ‘Reference Plant’ chemical fingerprinting (B. Markert). Based on the consolidation of studies devoted to the development and appliance of plant-matrix reference materials, a list of the most important requirements has been compiled for reference materials that ensure the reliability and comparability of the results of chemical analysis in the fields of biology, geochemistry, ecology, agriculture, medicine, and interdisciplinary research.

Elemental composition of dust aerosols near cement plants based on the study of samples of the solid phase of the snow cover

Abstract This study is focused on the quantification of dust load on snow cover and chemical elements content in the solid phase of snow cover in the impacted areas of cement plants (the south of Western Siberia). Applying the instrumental neutron activation analysis, we identified chemical composition in the samples of the solid phase of snow cover. The results demonstrated that the dust load corresponded to the permissible pollution levels in the living zones. Dust pollution level varied from moderately hazardous to highly hazardous in the north-western impacted zone of the cement plants and raw material open pits. It was found that the predominant chemical element is Ca, as well as a group of rare-earth (Yb, Tb, Sm, La, Ce, etc.) elements in the solid phase of snow cover from the impacted zone of the cement plants.

Phosphorus-Rich Ash from Poultry Manure Combustion in a Fluidized Bed Reactor

The aim of this study was to examine the physico-chemical and phase characteristics of ash obtained in the process of the combustion of Polish poultry manure in a laboratory reactor with a bubbling fluidized bed. Three experiments, differing in the grain size and morphology of the raw material, the method of its dosing and the type of fluidized bed, were carried out. The contents of the main chemical components and trace elements in the obtained ash samples were determined using WDXRF, and the phase composition was examined through the XRD method. The morphology and the chemical composition of grains in a given micro-area using the SEM/EDS method were also investigated. The highest concentration of phosphorus (from 28.07% wt. to 29.71% wt. as P2O5 equivalent), the highest proportion of amorphous substance (from 56.7% wt. to 59.0% wt.) and the lowest content of unburned organic substance (LOI from 6.42% to 9.16%) (i.e., the best process efficiency), was obtained for the experiment in which the starting bed was quartz sand and poultry manure was fed to the reactor in the form of pellets. It has been calculated that in this case, the amorphous phase contains more than half of the phosphorus. The method of carrying out the combustion process has a significant impact on the phase composition and, consequently, on the availability of phosphorus.

Study of the Silicon Carbide Wear Area after Micro-Scratching of Titanium, Zirconium, Niobium and Molybdenum at a Speed of 35 m/s

The authors conducted the study at micro-scratching of titanium, zirconium, niobium and molybdenum alloys. The content of the main element in alloys was from 99.5 to 99.7 %. Micro-cutting was carried out by specially prepared indenters with silicon carbide mono-crystals of a given shape. The state of the relief and the chemical composition of the wear area were studied using a scanning two-beam electron microscope. The micro-scratching speed was 35 m/s without cooling. The condition of the contact surfaces of silicon carbide and metals was studied at a magnification up to 100,000 times with the rotation and tilt of the microscope slide. The content of chemical elements was determined at individual spots of an object by scanning along the line and area. The authors also studied the condition of the wear area after micro-scratching of metals and after removal of metal adhesions by chemical etching. The intensity of metal transfer was determined by the average concentration of metal atoms at the wear area. The article also gives a classification of metals according to the intensity of transfer immediately after grinding and removal of metal adhesions. The influence of metal and the depth of micro-scratching on the morphology of the wear site is shown. It was found that molybdenum, having a low adhesive activity to silicon carbide, is able to penetrate microcracks and other surface defects during micro-scratching. The width of microcracks and the depth of metal penetration were determined

Chemical, physical, and biological attributes in soils affected by deposition of iron ore tailings from the Fundão Dam failure.

Monitoring degraded areas is essential for evaluation of the quality of the rehabilitation process. In this study, we evaluate how the physical and chemical characteristics of the mixture of iron ore tailings with the soil have affected the soil microbial biomass and activity in areas along the Gualaxo do Norte River after the Fundão Dam disaster. Composite soil samples were collected from areas that were impacted (I) and not impacted (NI) by the tailings. The following attributes were evaluated: chemical element content; soil density, porosity, and texture; microbial biomass carbon; basal respiration; and enzyme activity and density of microbial groups (bacteria, actinobacteria, fungi, arbuscular mycorrhizae, phosphate solubilizers, cellulolytic microorganisms, nitrifiers, ammonifiers, and diazotrophs). According to result, the deposition of tailings increased the pH and the soil available P, Cr, Fe, and Mn content and reduced organic matter. The physical and biological attributes were negatively affected, with increases in the silt content and density of the soil, and reduction in macroporosity and in the microbial biomass and activity of the soil (respiration and enzymes) in the impacted area. However, the impacted areas exhibited greater densities of some microbial groups (cellulolytic microorganisms, nitrifiers, and diazotrophic bacteria). Modifications in the organic matter and silt content are the main attributes associated with deposition of the tailings that affected soil microbial biomass and microbial activity. This may affect erosive conditions and the functionality of the ecosystem, indicating an imbalance in this environment. In contrast, the higher density of some microbial groups in the impacted areas show the high rehabilitation potential of these areas.

Landscape-geochemical specifics of steppe geosystems in Baikal basin

Landscape-geochemical studies of the steppe geosystems of the Lake Baikal catchment area revealed the spatial regularities of matter differentiation of the geosystem components and the landscape-geochemical features of geosystems at different levels of organization. The steppe geosystems occupy mainly the piedmont plain and the bottoms of the submontane and intermontane depressions. Dry steppe geosystems are confined to the lowest belt in the altitudinal zonality system. Regional and local features of landscape-geochemical differentiation of matter are diagnosed by the ratio of radial and lateral heterogeneity of the distribution of chemical elements. The steppe calcium and subtaiga sour-calcium geosystems are characterized by a weak radial contrast ratio in the content of different chemical elements in soils against the background of a well-pronounced lateral contrast, and at the contact of steppe and subtaiga geosystems. Lateral differentiation of the content of chemical elements is practically absent. Thus, at the contact of many low-mountain and piedmont landscape-geochemical systems (LGS) in the Preolkhon region, ecotones have been formed, which determine very weak differences between the soil parameters of forest and steppe geosystems. This has necessitated the display of types of conjugations (TC) on landscape-geochemical maps for a more correct reflection of the nature of the matter differentiation. In connection with the predominance of heterolithic conjugations in mountainous conditions, for a correct assessment of the lateral migration of matter, it is advisable to single out individual links of conjugated rows of facies formed on homogeneous bedrocks.

FEATURES OF THE CONTENT OF CHEMICAL ELEMENTS IN THE CONIFEROUS LARCH GMELINA IN THE AR-EA OF THE UDOKAN COPPER DEPOSIT

The article presents materials for the study of the content of chemical elements in the coniferous larch Gmelina (Larix gmelinii (Rupr.) Rupr.) family Pinaceae (syn.: Larix dahurica Turcz. ex Trautv., Larix amurensis Beissn.), growing in the high-altitude region of the North of the TRANS-Baikal territory, near the Udokan copper Deposit. The purpose of the research is to assess the concentration of a number of chemical elements in high-altitude and permafrost soils, while preparing the territory of the copper Deposit for exploitation. Selection of larch plant samples was carried out in the types of larch forests widely distributed in the research area, in June 2011. The analysis of pine needles samples was performed according to approved methods using modern instruments and equipment in the laboratory of Institute of Natural Resources, Ecology and Cryology SB RAS. It was found that in General L. Gmelin needles have a low concentration of chemical elements, which are arranged in the following sequence: Mg> Sr> Al> Ba> Fe > Ti> Ni> Cu> Mn> Hg> Zn> V> Ag> Cr> Pb> Cd> Sb> Co> Se> As. At the same time, mercury is the only element whose concentration in larch conifers is much higher, 3.8 times, than that of land plants. The article presents a correlation table of the interaction of chemical elements. The table shows that titanium, aluminum, zinc, and silver have a greater effect on the content of chemical elements in conifers. The results presented in the article were obtained in the studied area for the first time. It is important to use the results of this work to monitor environmental pollution, to take into account when using larch to obtain medicinal substances, and to increase the productivity of forest plantations. Further research in this area may be related to other areas of distribution of larch forests, geochemical assessment of the region.

EFFECT OF AUSTENITIC GRAIN SIZE ON THE PHASE TRANSFORMATION OF A NOVEL 6.5% Cr STEEL FOR FORGED COMPONENTS

In this paper the effect of quenching and tempering (Q&T) thermal treatment on mechanical properties of a novel 6.5% Cr steel for forged components is studied. The main innovation is in the increased hardenability following the higher Cr content with respect to the more common 5% Cr steel allowing to lower the content of other chemical elements aimed to achieve the target mechanical properties. Following to the high intrinsic hardenability of such steel based on the Cr content a poor effect of prior austenite grain size should be expected after quenching. Aim of this work is to evaluate such effect and to analyse the dependence of mechanical properties on it.

The use of smectite kizelgur in diets when rearing calves of the preweaning period

The use of grain feed mixtures in the diets of young cattle at an early age does not fully meet their need for minerals, because of which other nutrients cannot be used eff ectively enough. In this regard the current situation determines the need to use and develop recipes for grain feed mixtures with the inclusion of relatively inexpensive natural mineral additives in their composition from the early age of calves. The purpose of the work was to experimentally substantiate the inclusion in the grain feed mixture of different doses of smectite kizelgur and their effect on the productivity of young cattle during the preweaning period with its summer and winter housing. The doses of inclusion of smectite kizelgur in the composition of grain feed mixture for calves of the preweaning period and their effect on productivity and energy consumption per unit of growth have been studied. The most effective doses of smectite kizelgur in the composition of grain feed mixture for calves during the preweaning growing period under the conditions of their summer and winter maintenance have been established. In the experiment the content of vital chemical elements from different parts of the calves’ body in the hair has been studied as an indicator of the mineral status of their body when feeding smectite kizelgur in the grain feed mixture. It has been found during the research that when rearing calves in the preweaning period the use of different doses of smectite kizelgur in the diet has the positive effect on their growth and development, interior indicators and increases the economy of the industry. The inclusion of 20 g/head/day in the grain mixture in the summer period, and 30 g/head/day in the winter period of smectite kizelgur is the most economically justified.

Combinability Model of Chemical Compositions of Steel upon Adjustment of Chemical Element Content

Combinability Model of Chemical Compositions of Steel upon Adjustment of Chemical Element Content

The content of the main chemical elements in sweet cherry fruits of different ripening periods

The level of biochemical composition of sweet cherry fruits of different ripening periods was investigated. It has been established that the content of chemical elements in sweet cherry fruits depends on a number of factors. Fruits ripening period is listed frstaming the features of the pomological variety. Weather conditions during the formation and ripening of sweet cherry fruits have a signifcant effect on the content of chemicals. The variety Melitopolskaya krapchastaya was revealed to have a high content of dry soluble substances among all the studied varieties. In the group of late-ripening varieties, the smallest difference in the amount of acidifed acids in fruits between varieties is observed. The high content of organic acids was recorded for the Donetsk Ember variety, and the lowest one for the Turquoise variety. On average, for the varieties of different ripening periods, the highest content of organic acids was noted for early ripening varieties, and the lowest one for late ripening varieties. Having considered all the studied varieties as a whole, it can be asserted that the content of titratable acids was the highest in the fruits of the mid-ripening variety Alenushka, in relation to all other varieties; the lowest amount of organic acids was recorded for the late-ripening varieties Amazonka. The sugar content in the fruits of late-ripening sweet cherry varieties exceeded the average values of the groups of early-ripening and mid-ripening varieties. The mid-ripening variety Mirage was characterized by a high content of vitamin C, and the lowest value of this component of the chemical composition was obtained for the early-ripening variety Mlievskaya yellow. Taste qualities and biochemical composition of fruit and berry crops largely depend on the characteristics of the variety and climatic conditions of cultivation.The early ripening varieties Dar Mliyeva and Zoryana received the maximum tasting assessment. In the group of mid-ripening varieties, the Melitopolskaya krapchastaya variety was highly appreciated, and among the late-ripening varieties, the Turyuza variety. Key words: cherry varieties, dry soluble substances, sugars, organic acids, vitamin C, sugar-acid coefcient.

Influence of External Action on the Internal Structure of Continuously Cast Slab Produced from Tube Steel

The paper compares the internal structure of two continuously cast slabs with a section of 300 × 2600 mm from a tube steel of the strength class K60, one of which is molded with a soft reduction, and the other is without external influence. A comparative analysis of the structure of two templates showed that the location of areas with an increased metal pickle ness in the axial part of the templates varies. On the template from a slab cast without reduction, this section is below the geometric center of the work-piece in thickness, at a distance of 49.2% from the underside, that is, the "lower" asymmetry of the slab structure is observed. On the template from the slab cast off with soft reduction, the area with an increased pickle-ness is located above the middle of the work-piece: at a distance of 51.7% of the side of the large radius, an "upper" asymmetry of the slab structure is formed. Consequently, as a result of the external action on the cast work-piece, the location of the axial sponginess, relative to the geometric centre of the slab, is changed by moving from the lower to the upper half of the work-piece. The metal of the axial part of the reduced slab has a denser structure, the degree of development of axial looseness in the metallographic evaluation is reduced by an average of 0.5 points. The work shows the change in the content of chemical elements along the thickness of slabs. In the reduced metal, the maximum value of the degree of zonal inhomogeneity of the most impurities is higher than in the metal without external influence. This is explained by the fact that, as a result of reduction, the zone of location of the axial chemical heterogeneity in the slab becomes smaller in width.

Trace element accumulation by soils and plants in the North Caucasian geochemical province

Long-term studies of the North Caucasian geochemical province allowed to establish regional abundances and calculate accumulation (dispersion) factors for chemical elements in rocks, soils, and plants. Certain natural regional patterns characterize the province. Associations of elements in high and low concentrations are often determined by the predominant composition of rocks: carbonate-terrigenous, terrigenous, and igneous. The study of the average contents of several chemical elements in the soils of the province showed that the association of accumulated elements includes metals with different migration characteristics. Thus, despite the rather close values of the ionic radii, Pb, Zn, Cu, and Li (judging by the ionic potential) are characterized by the formation of cations, while Mn, Mo, and Zr form complex ions. Such elements as Zn, Cu, and Pb are mainly accumulated on hydrosulfuric barriers, while Mo, Co, and Mn are stopped by oxygenous barriers. For Cu, Zn, Mo, and Co, biogenic accumulation plays a significant role, while for Pb and Ni it is practically absent. The absolute dispersion of the elements did not reach environmentally hazardous values, although it indicates a fairly intensive migration. In woody plants, Ba, Nb, Sc, Sr, and Zn are accumulated most intensively.

Comparative evaluation of the milk composition of dairy cows in the Volgograd region

The article presents the results of determining the indicators of milk productivity of dairy cows in the Volgograd region. The studies processed the data of monthly control milking of five large agricultural enterprises of the region (LLC JV “Donskoe” Kalachevsky district, PZK “Put Lenina” Surovikinsky district, “Vostok” Nikolaevsky district, “PZK named after Lenin” Surovikinsky district, FSUE “Irrigated” Sovetsky district ). A comparative characteristic of the milk yield of the presented breeds of cattle in different periods of the year is given. Physicochemical definitions of milk quality indicators were carried out according to generally accepted methods - fat content (GOST R ISO 2446-2011) and protein (GOST 23327-98). A comparative analysis of the fat and protein content in the milk of dairy cows by periods of the year is presented. To analyze the chemical composition of milk samples by inductively coupled plasma mass spectrometry (ICP-MS), a Nexion 300D quadrupole mass spectrometer (Perkin Elmer, USA) was used. The determination of the chemical composition of milk samples by inductively coupled plasma atomic emission spectrometry (ICP AES) was carried out using an Ortima 2000DV atomic emission spectrometer (Perkin Elmer, USA). The results obtained showed the content of chemical elements in the milk of cows in the summer period within the limits of permissible concentrations, including the content of heavy metals (cadmium, mercury, lead, arsenic). Studies carried out with milk samples obtained from animals from all experimental farms have shown that the controlled indicators of milk quality, the content of chemical elements correspond to regulatory documents and raw milk of all farms is recommended for use in the production of all types of fermented milk and dairy products.

Elemental composition of salt sediments of drinking water in Northern Kazakhstan (the case of Akmolа and Northern Kazakhstan regions)

The relevance of the work is due to the possibility of using drinking water scale as an indicator of water quality. The results of studies of salt deposits (scale) of drinking water in Akmola and North Kazakhstan regions, obtained by the method of instrumental neutron activation analysis in a certified laboratory of Tomsk Polytechnic University, are presented. The contents of the following 28 chemical elements are determined: Na, Ca, Sc, Cr, Fe, Co, Zn, As, Br, Rb, Sr, Ag, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Yb , Lu, Hf, Ta, Au, Th, U.  Based on the results of the analysis, the calculation of the statistical parameters of the content of chemical elements in the scale in Northern Kazakhstan was carried out. The data on the scale content relative to the average value for the Akmola region, which showed the accumulation of scandium, arsenic, silver, antimony, cesium, barium, neodymium, samarium, terbium, ytterbium and lutetium, and for the North Kazakhstan region of sodium, chromium, lanthanum and uranium. Geochemical series have been constructed and the following specific elements have been identified in terms of the concentration coefficient in the studied territories: Sc, Fe, Co, Ag, Cs, Hf, Ta, Th, Nd, Sm, Sr, Sb. The presence of these elements in the salt deposits of drinking water in Northern Kazakhstan can be explained by the peculiarities of the geological structure of the territories and anthropogenic load. Key words: chemical elements, indicator, salt deposits, scale, instrumental neutron activation analysis, Northern Kazakhstan.

Pollen and Chemical Content of Beebreads from Serpentine Areas in Albania and Bulgaria.

Beebread from serpentine localities in Albania and Bulgaria were characterized based on their pollen and chemical element content (macroelements K, Ca, Mg, P and microelements Cd, Co, Cr, Cu, Fe, Mn, Na, Ni, Pb, Zn) aiming to (1) evaluate the effect of serpentine soil on the quality of beebread; (2) compare elemental concentrations in samples from serpentine areas in Albania and Bulgaria; and (3) compare the differences in pollen spectra. Chemical element content was determined using microwave digestion of beebread samples followed by ICP-OES measurements. The analytical procedure developed was validated by added/found method. Analytical figures of merit of analytical method proposed were presented. The melissopalynological analysis was applied for pollen characterization. The results demonstrate clear difference in the pollen spectra between the two sets of samples, confirming differences in local serpentine flora in both countries, but specific pollen type is difficult to be suggested. The pollen content is related to the flowering period, climatic conditions, and bees forage preferences. The samples vary in their elemental concentrations depending on the pollen type and year of collection. The highest average concentrations found for K, Ca, Mg, and P are close to values reported in the literature. However, elevated concentrations observed for Ni, Cr, Mn, and Fe in beebread, especially from Albania, are in line with the serpentine characteristics of studied areas. The concentrations of Cd and Pb for all beebread samples are below permissible limits. The results should be taken into consideration in future specific food safety regulations at national and international level.

Влияние пробиотического штамма Bifidobacterium longum на содержание химических элементов в биологических тканях цыплят-бройлеров при минералдефицитной диете

Abstract. The study is aimed at studying the effect of the probiotic strain Bifidobacterium longum on the content of chemical elements in the biological tissues of broiler chickens against the background of a mineral-deficient diet. Methods. The research was conducted on cross Arbor-Icers broiler chickens between the ages of 7 and 42 days old. From the 21-day-old age of chickens, two groups of 15 heads each were formed by the method of analogs, the studied bird was kept on a mineral-deficient diet. Poultry of the experimental group received a liquid probiotic preparation “Soy-bifidum” in a dosage of 0.7 ml/kg of feed. Features of the exchange of chemical elements were determined by studying the content of the elemental composition of the liver, thoracic and femoral muscles on 25 indicators. Results and practical significance. The additional inclusion of the probiotic strain in the diet contributes to the maximum elimination of toxic elements, thereby reducing the intoxication of the entire body. Thus, the probiotic strain Bifidobacterium longum contributed to a significant decrease of aluminium in the liver by on 34 % (p = 0.048), lead – 50 % (p = 0.008), tin – 67 % (p = 0.0064), aluminium in the thoracic muscles by 54.6 % (p = 0.005), and cadmium by 55.6 % (p = 0.005), cadmium in the femoral muscles by 50 % (p = 0.006), lead by 75 % (p = 0.001), strontium – 50 % (p = 0.013) compared to such values in the control group. Scientific novelty. There were described the features of elemental metabolism by 25 indicators of broiler chickens with the introduction of probiotic drugs against the background of a mineral-deficient diet for the first time.

БРОМ В ЛИСТЬЯХ ТОПОЛЯ УРБАНИЗИРОВАННЫХ ТЕРРИТОРИЙ: ПРИРОДНЫЕ И АНТРОПОГЕННЫЕ ИСТОЧНИКИ ПОСТУПЛЕНИЯ

Актуальность исследования. Бром является толассофильным, органофильным и эссенциальным элементом. Сочетание природно-антропогенных источников рассеяния этого элемента обуславливает комплексность и многофакторность его поступления в окружающую среду, оказывает влияние на особенности накопления и распределения галогена в природных средах. Основное внимание в работе сосредоточено на урбанизированных территориях локального и регионального уровней исследования с источниками эмиссии Br. Пути миграции и биогеохимической аккумуляции брома остаются слабо изученными вопросами. Цель: определить количественные содержания Br в листьях древесных растений рода тополь (Populus L.), произрастающих на урбанизированных территориях юго-востока Евразии, и на основе принципов биогеохимического районирования выявить ореолы Br нагрузки, определить главные факторы их формирования. Объект и методы. Объектом исследования являлись листья тополя (Populus L.). Отбор проб проведен в августе 2015–2018 гг. на территории 50 городов по равномерной сети с шагом 1×1 и 2×2 км. Средний объем выборок в городах составил 30 проб. Всего отобрано 1686 проб листьев тополя. Озоление листьев проводилось методом сухой минерализации в муфельной печи при температуре 450 °С в течение 5 час. Принимались во внимание литературные данные о том, что потери Br в золе, полученной при 400 °С, составляют не более 20 % от расчетной величины. Определение содержания Br и других химических элементов в золе листьев тополя проводилось методом инструментального нейтронно-активационного анализа в ядерно-геохимической лаборатории на исследовательском учебном ядерном реакторе (ИРТ-Т) в Томском политехническом университете. Результаты анализов обработаны методами описательной статистики, кластерного и дискриминантного анализов. Результаты. Среднее содержание Br в золе листьев тополя урбанизированных территорий составило 56,5±2,1 мг/кг, при разбросе от 0,3 до 1730,1 мг/кг. Медиана – 30,6 мг/кг. Нижнее аномальное содержание Br составило 103,4 мг/кг. Выявлены две сопряженные аномальные бромные биогеохимические области: Кулундинская – природного генезиса, и Северо-Казахстанская – природно-техногенного генезиса. Области объединены в бромную биогеохимическую субпровинцию, впервые описываемую в данной работе.

Energy Potential of Agri Residual Biomass in Southeast Asia with the Focus on Vietnam

Southeast Asia currently faces a huge increase in energy consumption and serious environmental issues. A widely underutilized and still unexplored potential of these countries lies in residual biomass. In the present research, the production quantities and energy yields of the most abundant agricultural byproducts in Vietnam, i.e., rice straw, rice husks, sugarcane bagasse and sugarcane trash, were calculated. Total crop yield, residues ratio and net calorific values of the wet basis biomass served as input parameters for the calculations. Moreover, the results were found for individual regions and provinces of the country. The findings show that the production of paddy rice straw is an enormous 97 million tons per year with an energy potential of over 380 TWh, as well as another 9 million tons yearly and 35 TWh in the case of rice husks. More than half of rice biomass production is concentrated in the Mekong River Delta region. Harvesting and processing of sugarcane annually generates about 5 million tons of bagasse and over 3.5 million tons of sugarcane trash with the total energy potential of about 27 TWh, which is primarily available in the central regions of Vietnam. The detailed laboratory determination of fuel-energy properties of studied materials, such as gross and net calorific value, volatile matter, ash and moisture content and contents of chemical elements was also carried out. Based on the research results and literature analysis, the possibilities of biofuel production and energy utilization of the above-mentioned residues are discussed.