Results Of Chemical Analysis Research Articles

The effect of sodium tartrate and sodium citrate on quality changes of squid (Dosidicus gigas) surimi gel.

The yield of squid has grown gradually; however, the lack of intensive processing has led to the slow development of the squid industry. In a previous study, some organic salts were found to improve the quality of squid surimi gel. Therefore, this research focused on the effects of sodium citrate (SC) and sodium tartrate (ST) on the quality of squid surimi gel. Physical measurements, such as gel texture, water-holding capacity, and color of squid surimi gel, were conducted. The addition of 2.5% SC and ST significantly improved the gel strength by 40.7, 57.0, 22.9, and 58.1%, respectively, of gel strength compared with the addition of: 1.5 SC, 3.5 SC, 1.5 ST, and 3.5% ST alone. Rheological measurements revealed that the addition of 2.5% SC or ST shortened the gel degradation temperature range (i.e., 2.5% SC or ST: 40-53°C; other treatments: 40-60°C) of the squid paste during heating. Results of chemical force analysis showed that the addition of a high quantity of salt accelerated protein aggregation and reduced hydrophobic interactions and disulfide bond formation. Finally, an increase in the number of β-sheets and a decrease in the bulk water content demonstrated that the addition of 2.5% organic salt could form squid gel with a better network structure. The findings provide a scientific basis for the development of high-quality squid surimi gel.

The Content of Cd and Pb in Herbs and Single-Component Spices Used in Polish Cuisine

Spices and herbs play an important role in the human diet, mostly due to the presence of essential oils and high antioxidant activity. Therefore, the toxicity of metals raises concerns about the safety of consumption of spices and herbs. This paper examines the content of Cd and Pb in fresh and dried herbs and single-component spices that are the most popular in Polish cuisine: 100 samples of nine kinds of dried herbs, 184 samples of 15 kinds of fresh herbs and 148 samples of 14 kinds of loose single-component spices. The level of Cd and Pb was determined using the GF AAS method. The safety of herbs and spices for consumption was estimated based on the percentage intake of Cd and Pb compared with the tolerable intake (% TWI, % BMDL), chronic daily intake (CDI), target hazard quotient (THQ), hazard index (HI) and comparisons of the results of chemical analyses with the maximum admissible levels of Cd and Pb in Poland and in the European Union. Calculated per fresh weight of the product, dried herbs on average contained 0.134 ± 0.168 mg of Cd and 0.548 ± 0.161 mg of Pb per kg−1, fresh herbs on average contained 0.004 ± 0.007 mg of Cd and 0.039 ± 0.033 mg of Pb per kg−1, and the mean content of Cd in spices was 0.017 ± 0.019 mg per kg−1 and 0.064 ± 0.050 mg of Pb. The % TWI, % BMDL, CDI, THQ and HI (Cd + Pb) for all the analysed products were lower than 1. The results do not imply a risk due to the supply of Cd and Pb with the diet to the human body, primarily due to the small intake of these products. However, it should be highlighted that the content of Cd in dried coriander and estragon and that of Pb in watercress, jiaogulan, celery, basil and dill exceeded the acceptable limit. Thus, their consumption for people from particularly sensitive groups such as babies, pregnant and breastfeeding women and people should be carefully limited.

SEM-EDS identification of glass groups in Meroitic period and Early Nobadian Nubia

ABSTRACT This article presents the results of chemical analysis using SEM-EDS on 136 vitreous bead and vessel samples found at Faras and Qasr Ibrim (Lower Nubia), and Gabati and Meroe (Upper Nubia) in Sudan dating to the Meroitic (c. 350 BC–AD 350) and Early Nobadian (c. AD 350–600) periods. The results revealed a great variety of chemical groups and types, indicating the presence of glass from multiple origins. Many of these glass samples match the known Mediterranean glass groups to suggest a potential provenance for some of the glasses. However, a number of samples from Gabati did not fit within these groups and the presence of glassy faience at Qasr Ibrim may highlight further nuances of vitreous material production and the potential for more locally based practices.

Stripping propensity detection of HMA Mixes: With focus on image processing method

• The incorporation of anti- Stripping in hot mix asphalt was investigated. • The effects of anti- Stripping agents on the specimens by image processing were evaluated. • The performance of specimens under different working conditions was analyzed. • Anti-stripping agent improved of adhesive property of HMA asphalt mixtures. Infiltration of water into Hot Mix Asphalt (HMA) can cause performance degradation and service life reduction of the asphalt concrete pavements. Moreover, it can lead to adhesion failure at the binder-aggregate interface and/or cohesion failure within the binder or binder-filler mastic. In this paper, three aggregate types, three anti-stripping additives, and one bitumen type were selected to study this phenomenon. Based on the results of chemical analysis, selected aggregates were categorized into two groups: non-stripping and stripping aggregates. Then, the stripping propensity of loose and compacted mixes was assessed through boiling water, retained compressive strength, and indirect tensile tests. The chemical analysis was showed the importance of amphoteric and alkaline oxides in moisture sensitivity in silicate rocks. The results emphasize the detrimental effect of moisture in HMA mixes even in the non-stripping mix. All selected anti-stripping additives improve the tensile strength ratio (TSR) of specimens, however, the stripping propensity of some treated mixes was maintained. In the next step, cohesion loss and adhesion loss surfaces of loose mixes and ITS specimens was determined under the wet conditions by the image processing technique in ENVI and MATLAB software packages. Based on image processing results, the higher retained bitumen coating in loose mixes leads to less stripping propensity of compacted specimens and the tensile strength ratio of modified Lottman specimens is decreased by an increase in the percentage of broken aggregates and adhesion loss. Image processing data were subjected to nonlinear regression and multiple analysis of variance (MANOVA) to investigate this phenomenon.

Ақтөбе қаласының топырағының ауыр металдармен ластануын экологиялық бағалау

This article discusses the results of chemical analysis of mobile forms of chemical elements (Cu, Ni, Pb, Zn, Co, Cd, Mb, Cr, Fe) in the soils of Aktobe city. Soil samples from 7 test plots in the territory of Aktobe city are studied. The concentrations of chemical elements are determined, and the concentration coefficients and the total index of soil pollution with heavy metals (Zc ) are calculated. The calculation results show that the level of soil pollution with heavy metals in 4–8 micro-districts and the area “Aviagorodok” is within Zc = 19.4–22.2 (16 < Zc < 33 is an average, moderately dangerous level), while in other studied zones it shows Zc < 16, i.e. low pollution.

CHARACTERISTICS OF MILK CARAMEL CANDY WITH THE ADDITION OF STEVIA (STEVIA REBAUDIANA BERTONI) EXTRACT LEAF POWDER

The aime of this study was to determine the characteristics of milk caramel candy with the addition of stevia extract leaf powder (Stevia rebaudiana Bertoni) based on the physical, chemical properties, and level of acceptance of the panelists for milk caramel candy. The addition of stevia extract leaf powder to the milk caramel candy was expected to be reduce the value. This study used a completely randomized design (CRD) with 5 treatments and 3 replications. Data analysis using ANOVA and further testing of DNMRT at a 5% significance level. The treatments in this study were the level of addition of stevia extract leaf powder is A (0%), B (0.1%), C (0.2%), D (0.3%), and E (0.4%). The results showed that the addition of different stevia extract leaf powders in milk caramel candy was significantly different at the 5% level on the analysis of the water content, protein content, energy, antioxidant activity, color analysis, organoleptic tests (color, and taste) and the level of addition of stevia extract leaf powder was not significantly different at the 5% level on ash content, fat content, reducing sugar, hardness analysis and organoleptic (aroma and texture) analysis. The best treatment in this study was addition of 0.2% stevia extract leaf powder, the results of chemical analysis showed that the average water content was 9.28%, ash content was 1.87%, protein was 13,91%, fat was 9,69%, reducing sugar was 8.21%, energy value (calories) 403,86 cal/g, antioxidant activity 43.04%, physical analysis of hardness 89.40 N/cm2, color 126.88 ºHue, and organoleptic test results were color 4.35 (like), aroma 3.65 (like), taste 4.25 (like), and texture 3.85 (like).

Can sensory boar taint levels be explained by fatty acid composition and emitted volatile organic compounds in addition to androstenone and skatole content?

This study aimed at understanding which molecules were responsible for the differences existing in boar taint sensory evaluation. The latter was therefore linked to the results of skatole and androstenone chemical analyses, fatty acid composition and VOC profiles of heated backfat. This study confirmed that some discrepancy exists between chemical analysis and sensory evaluation of tainted backfats. Significant correlations between human nose scores and fatty acid composition were not revealed. Strong correlations between emissions and contents in skatole and androstenone were found. Oxidation products of polyunsaturated fatty acids, with fatty odor descriptors, were found to be more present in the VOC profiles of boar fat considered untainted through the human nose methodology. Weak coefficient of determination for partial least square regression indicates that other factors, yet unknown, are responsible for sensory evaluation outcomes. These findings hence support the idea that high human nose score is mainly due to boar taint compounds rather than general differences in VOC profiles.

Yield and Nitrogen Status of Maize (Zea mays L.) Fertilized with Solution of Urea—Ammonium Nitrate Enriched with P, Mg or S

UAN is a popular nitrogen fertilizer, broadly used in world agriculture. Research concerning the effects of this fertilizer is just as common. Contrarily, studies on the combined application of UAN with P, Mg or S are lacking. This fact has stimulated our study, undertaken in order to evaluate the effects of maize grown for grain and fertilized with UAN enriched with the macronutrients (P, Mg and S) on the crop’s yields and nitrogen metabolism. The following nitrogen fertilizers were applied: UAN 32%N, UAN + S—26% N + 3% S, UAN + P (Medium)—26% N and 11% P2O5, UAN + P (Starter)—21% N and 18% P2O5, UAN + Mg—20% N + 4% Mg. Based on the results of chemical analyses and yields of maize, the following indicators of nitrogen use efficiency (NUE) were calculated: agricultural efficiency (AE), physiological efficiency (PE), internal N utilization efficiency (IE), reciprocal internal N utilization efficiency (RIE), grain share in N accumulation (HIN), recovery of N from mineral fertilizers (RN) and partial nitrogen balance (PNB). The highest grain yields were harvested after the application of UAN + S/UAN + Mg, and after the pre-sowing and top-dressing application of UAN or UAN + P (Medium). Values of all calculated nitrogen use efficiency indicators were more strongly dependent on the weather conditions, which determined volumes of maize yields in a given year, than on the applied fertilization.

Properties of soils of different lithology in the humid tropics of southeastern nigeria

This study evaluated the properties of soils developed on diverse parent materials in Ogoja Local Government Area. Five profile pits on five different parent materials were dug, morphologically delineated and described. The five parent materials were basement complex (BC), mudstone (MS), sandstone (SS), shalestone (SH) and limestone (LS). Morphologically, the soils were deep with varying color, structure, texture and consistency. The results of chemical analyses revealed that the soils have acid pH with means of 5.4, 5.4, 5.4, 5.3 and 5.4 in BC, MS, SS, SH and LS. Organic carbon was low (<15g/kg) across the parent materials while total N was slightly higher in MS, SS and LS with means of 0.04 g kg-1, 0.10 g kg-1, 0.04 g kg-1, 0.10 g kg-1 and 0.20 g kg-1 in BC, MS, SS, SH and LS accordingly. Available P was low (<8mg/kg) across the parent materials with slightly higher value recorded in SH than in other parent materials. Calcium and sodium were the dominant and the least bases respectively with mean values of 3.2 cmol/kg, 3.93 cmol/kg, 3.65 cmol/kg, 3.3 cmol/kg and 3.95 cmol/kg and 0.25 cmol/kg, 0.10 cmol/kg, 0.08 cmol/kg, 0.08 cmol/kg, 0.08 cmol/kg in BC, MS, SS, SH and LS respectively. Exchangeable bases were higher in MS than other soils. Both Al3+ and H+ contributed at the same level to acidity of the soils. Correlation analysis showed that sand correlated negatively and significantly with clay (-0.81), OC (-0.41), TN (-0.42), and Al+++ (-0.78) and positively and significantly with pH (0.72), Ca2+ (0.7), Mg2+ (0.64), K+ (0.56), ECEC (0.71) and BS (0.70). Correlation between pH and exchangeable bases, available P (0.83), ECEC (0.9) and base saturation (0.83) was significant and positive. However, most properties had negative and non-significant correlation with each other.

Ferromagnetism in defective yttria-stabilized zirconia

Significant research attention has been devoted to identifying and synthesizing new magnetic materials via doping of non-magnetic materials. The material defects offer an approach to stabilize ferromagnetism in non-magnetic materials such as oxygen-deficient HfO2 and oxygen-deficient ZrO2. In this study, we demonstrated room-temperature ferromagnetism via nitrogen ion implantation on yttria-stabilized zirconia (YSZ) single crystals. The results of structural and chemical analyses indicate the formation of a distinct surface layer through the implantation of nitrogen ions and potential oxygen vacancies. The lattice constant in this surface layer increased by 0.6% compared to the bulk value. Nitrogen ions were observed in this region, and their concentration was estimated to be 2.32 atoms per unit cell. In contrast to the lack of magnetic hysteresis in a YSZ single crystal, ferromagnetic hysteresis was observed in the ion-implanted YSZ crystals, owing to defects—nitrogen ions and oxygen vacancies in the surface layer.

The chondrite breccia of Antonin (L4‐5)—A new meteorite fall from Poland with a heterogeneous distribution of metal

AbstractOn July 15, 2021, a huge fireball was visible over Poland. After the possible strewn field was calculated, the first and so far only sample, with a mass of 350 g, was discovered 18 days after the fireball event. The Antonin meteorite was found August 3, 2021, on the edge of a forest close to a dirt road near Helenow, a small suburb of the city of Mikstat. The rock is an ordinary chondrite breccia and consists of equilibrated and recrystallized lithologies. The boundaries between different fragments are difficult to detect, and the lithologies are of petrologic type 5 and type 4. The rock is moderately shocked (S4) and contains local impact melt areas and thin shock veins. The low‐Ca pyroxene and olivine are equilibrated (Fs20.6and Fa24.0, respectively), typical of L chondrites. The L chondrite classification is also supported by O isotope data and the results of bulk chemical analysis. The Ti isotope characteristics confirm that Antonin is related to the noncarbonaceous (NC) meteorites. One of the studied thin sections shows an unusual metal–chondrule assemblage, perhaps indicating that the metal in the chondrite is heterogeneously distributed, which is, however, not clearly visible in the element abundances.

Экологический мониторинг загрязнения почв нефтью и нефтепродуктами, приуроченных к нефтяным месторождениям Удмуртии

This article discusses the problem of soil contamination with oil and petroleum products from one of the oil fields of the Udmurt Republic. Environmental monitoring of soil pollution was carried out at the license area of the oil field under study. The assessment of the soil condition was obtained during the survey at specially designated points 1 (bush 2), 2 (well 221), 3 (bush 17), 4 (bush 14), 5 (UPN), 6 (bush 16) according to the developed environmental monitoring program. The conducted environmental studies, as well as environmental monitoring data for the reporting period 2014-2017, allowed us to identify patterns of growth in concentrations of oil and petroleum products depending on the season of the year and soil sampling points. It is noted that on the territory of the oil treatment plant, the content of pollutants reaches maximum values. In general, the content of petroleum products varies from 5.7 mg/kg to 810 mg/kg. Based on the results of quantitative chemical analyses of soil samples, it was revealed that the level of oil pollution of the territory of the studied field is within acceptable values. Keywords: OIL POLLUTION, SOILS, MONITORING, OIL, PETROLEUM PRODUCTS, DEPOSIT

Quantitative risk assessment and risk reduction of integrated acid gas enrichment and amine regeneration process using Aspen Plus dynamic simulation

Dynamic simulation provides a novel tool in risk assessment that is capable of predicting process behavior in different situations, quantifying unsafe process boundaries and examining the propagation of deviations through the process. This study investigated the most frequent disturbances in the integrated acid gas enrichment and amine regeneration process in the natural gas refinery including disturbances in amine regeneration column temperature, feed flow rate, pressure, and gas leakage from the top product stream. Using Aspen Plus dynamics simulations, the consequences of various deviation scenarios and a detailed analysis of the reasons for the occurrence of the consequences were elaborated. The calculated propagation time from the beginning of each disturbance to the occurrence of an accident makes it possible for the operators to plan the necessary arrangements and effective measures based on the available response time. Furthermore, the consequences of flooding and weeping leading to changes in product quality are numerically ranked to facilitate comparing and prioritizing these consequences. Finally, based on the simulation results, new protective layers were designed to prevent various high-risk consequences. The complexity of the integrated process evaluated in this study illustrates the generalizability of the HAZOP dynamic method to achieve new results in chemical process hazard analysis thus serving as a useful tool for process safety specialists.

Incident Precipitation, Throughfall and Stemflow chemistry in <i>Pinus wallichiana</i> A.B. Jack. stand in Dal Lake catchment, Srinagar, J & K, India

The paper presents the results of chemical analysis of stem flow, throughfall and incident precipitation under Pinus wallichiana stand located in Dal Lake catchment in Kashmir Himalayas. The maximum values of Na (10.6 mg l -1), Cl (7.0 mg l -1) and K (2.3 mg l -1) were found in throughfall followed by stemflow (Na = 7.2 mg l -1; Cl = 4.6 mg l -1; K = 1.4 mg l - 1) and incident rainfall (Na = 4.8 mg l -1; Cl = 3.0 mg l -1; K = 1.0 mg l -1). In case of phosphorus however, the maximum values (1.5 mg l -1) were found in incident rainfall and minimum (0.8 mg l -1) in throughfall. The values of all four nutrients varied significantly (P < 0.05) during the course of the study. General trend of increase in nutrients in stemflow, throughfall and incident rainfall was in the order of Na > Cl > K > P. All four nutrients of the stemflow were significantly (P < 0.05) and positively correlated with the diameter at breast height (DBH), and inversely correlated with tree height, however this relationship was not significant. In case of throughfall, Na (r = 0.46), Cl (r = 0.60), K (r = 0.57) and P (r = 0.59) were significantly (P < 0.01) correlated with the crown area.

Study of Natural Cellulose Fiber’s Characters in Holoptelea integrifolia Tree Bark

ABSTRACT Natural fibers removed from the bark of Holoptelea integrifolia were characterized by chemical testing, FTIR spectroscopy, XRD, thermal analysis, and FESEM and EDAX morphological analysis. The results of chemical analysis show 65.30% cellulose, 1.36 g/cc density, and 14.69% moisture content. The results of XRD studies show 37.42% crystallinity index and 5.48 nm crystallinity size of the tested samples. Thermal studies show that after 235°C, fiber degradation occurs. SEM results prove the existence of cellulose fibrils and accumulation of polysaccharides over the fiber surface. EDAX shows an O/C ratio of 0.5419. The above results prove that Holoptelea integrifolia can be utilized as a promising reinforcement in polymers for making weightless components.

Impacts of cyanobacterial biomass and nitrate nitrogen on methanogens in eutrophic lakes

Methanogenesis is a key process in carbon cycling in lacustrine ecosystems. Knowledge of the methanogenic pathway is important for creating mechanistic models as well as predicting methane emissions. Due to low concentrations of methyl substrates in freshwater lakes, the proportion of methylotrophic methanogenesis is believed to be negligible in such environments. However, the high abundance of methylotrophic methanogens previously detected in Dianchi Lake suggests that methylotrophic methanogenesis may be underestimated in eutrophic lakes, whereas their influencing factors and mechanisms are not yet clear. In this study, the effects of cyanobacteria biomass (CB) or/and nitrate nitrogen on methanogenesis, especially methylotrophic pathway, in eutrophic lakes were investigated using microcosm simulation experiments combined with chemical analysis and high-throughput sequencing techniques. The results showed that either CB or nitrate nitrogen had significant effects on methane flux, the archaeal diversity and community structure of methanogens. Functional prediction, together with the result of chemical analysis, revealed that CB could promote methylotrophic methanogenesis by providing methyl organic substrates, while nitrate nitrogen increased the relative abundance of obligate methylotrophic methanogens by competitively inhibiting the other two methanogenic pathways. In eutrophic lake where both CB and nitrate present at a high concentration, methylotrophic methanogenesis could play a much more important role than previously believed.

Fortification of Red Tilapia Bone Flour as a Source of Calcium on Doughnut Preference Level

This research aims to determine the percentage of addition of red tilapia bone flour as a source of calcium in the most preferred doughnut. The research was conducted on January until February 2022 at the Fishery Product Processing Laboratory, Faculty of Fisheries and Marine Sciences, Universitas Padjadjaran and the Test Services Laboratory, Faculty of Agricultural Industrial Technology, Universitas Padjadjaran. The research method used was experimental method, that made doughnuts with different levels of addition of red tilapia bone flour, which consists of 5 treatments (0%; 2.5%; 5%; 7.5%; and 10%) with 20 panelists semi-trained as a test to determine the preference level of the panelists to doughnuts. Observations were made on organoleptic tests and chemical tests. The most preferred fortification of red tilapia bone flour on doughnut was the 5% treatment with the value of the preference level on appearance, texture, and aroma being 7 (preferred) and taste was 9 (very preferred). The results of chemical test analysis on 5% treatment for moisture content is 18,91%, ash content is 2,97%, protein content is 6,29%, fat content is 27,95%, carbohydrate content is 43,88%, and calcium content is 0,1007% or 1006,60 mg/kg.

Combining eDNA and morphological approaches to reveal the impacts of long-term discharges of shale gas wastewaters on receiving waters

The potential threats of shale gas wastewater discharges to receiving waters is of great concern. In this study, chemical analyses and biomonitoring were performed three times in a small river that received treated wastewater over a two-year period. The results of chemical analyses showed that the concentrations of chloride, conductivity, barium, and strontium increased at the discharge site, but their concentrations decreased considerably farther downstream (≥500 m). The concentrations of toxic organic compounds (16 US EPA priority polycyclic aromatic hydrocarbons and 6 priority phthalates), trace metals (strontium, arsenic, zinc, copper, chromium, lead, cadmium, nickel, and neodymium), and natural radionuclides (40K, 238U, 226Ra, and 232Th) were comparable to the corresponding background values or did not exhibit obvious accumulation in sediments with continued discharge. Morphological and environmental DNA approaches were used to reveal the potential effects of wastewater discharges on aquatic ecosystems. The results showed that the community structure of benthic invertebrates was not altered by the long-term discharges of shale gas wastewaters. However, the biodiversity indices (richness and Shannon) from the two approaches showed inconsistencies, which were caused by multiple reasons, and that substrates had a strong influence on the morphological biodiversity indices. A multimetric index was proposed to further analyze morphological and environmental DNA data, and the results showed no significant difference between the upstream and downstream sites. Generally, the chemical and biological results both demonstrated that the discharges of shale gas wastewaters had limited impacts on river ecosystems within two years.

Effect of Using Azolla as A protein Source on Cuts and Carcass Characteristics of Awassi Lambs

This study was conducted in the animal field of the College of Veterinary Medicine - Tikrit University, for the period from 13-10-2021 to 12-1-2022 preceded by a preliminary period of 10 days, where 15 Awassi lambs were used, ages ranged between 5-6 months, with a starting weight of 20. 13 ± 0.56 kg The lambs were randomly distributed to three treatments (T1) A ration free of azolla plants (T2) Replacement of 3% of wheat bran with azolla from the dry matter of the ration (T3) Replacement of 5% of wheat bran with azolla of the dry matter of the ration. The results in this study indicated the following: 1- Significant differences were found between the treatments in some results where the second and third treatments were significant over the first treatment in carcass characteristics for the traits (empty body weight, hot carcass weight and cold carcass weight), slaughtering residues, where the second and third treatments were significant over the first treatment in carcass traits for the traits ( Empty body weight, hot carcass weight and cold carcass weight), the results of chemical analysis of the carcass, where the third treatment outperformed the first and second treatments with a difference of (3.607 and 5.177) % for the first and second treatments, respectively, in moisture content. Also, the second treatment outperformed the first and third treatments with a difference of (1.57 and 5.177)% for the first and third treatments, respectively, in the percentage of dry matter, and the second treatment exceeded the first and third treatments with a difference of (1.563 and 2.603)% for the first and third treatments, respectively, in the percentage of protein. There were also arithmetic differences, where the second treatment outperformed in the percentage of weight of the main pieces (thigh, shoulder) compared to the rest of the treatments. The first treatment gave the highest percentage of weight for the ribs and cotton compared to the rest of the treatments. 2- There were no significant differences for each of the secondary cuts of the carcass (chest, flank and ulna), as well as the neck and buttocks, the area of the ocular muscle and the thickness of the fat layer, slaughter residues (head, limbs, skin, heart, heart fat, liver, lungs and trachea, full rumen, Full intestine, belly fat and digestive system contents), physical separation of the proportions (meat, fat and bone) of the ribs, (grooming ratio based on hot carcass weight, dressing ratio based on cold carcass weight and carcass weight loss percentage), chemical analysis results (ratio fat, ash and carbohydrates).

Distribution of Rare Earth Elements and Yttrium in Sediments From the Clarion‐Clipperton Fracture Zone, Northeastern Pacific Ocean

AbstractDeep‐sea sediments enriched in rare earth elements and yttrium (REY) are attracting scientific and exploration attention as a new REY resource. In the Clarion‐Clipperton Fracture Zone (CCFZ) of the northeastern Pacific, sedimentary units with high REY contents (average REY content >700 ppm) occur sporadically at only a few decimeters beneath the sediment surface covered with polymetallic nodules. Here we report the results of bulk chemical and sequential extraction analyses of sediment cores containing these units, collected from the southeastern part of the CCFZ. Correlations between element contents and shale‐normalized REY patterns suggest that the REY are associated primarily with calcium phosphates. Sequential extraction to determine the contribution from different sedimentary components confirms that calcium phosphates contain >70% of trivalent REY in REY‐enriched units. Despite the study location being favorable for nodule formation and subject to distal hydrothermal plume fallout, only subordinate amounts of REY are hosted by Mn‐ and Fe‐(oxyhydr)oxides. Hydrothermal Fe‐(oxyhydr)oxides may have played a more important role in accumulating REY, as evidence suggest that large amounts of Fe‐(oxyhydr)oxides have been transformed into Fe‐rich smectite during early diagenesis of REY‐enriched units.