Changes In Element Concentrations Research Articles

The earliest Badenian Planostegina bloom deposit: reflection of an unusual environment in the westernmost Carpathian Foredeep (Czech Republic)

The Miocene sedimentation history of the Brus denudation relict (the western part of the Carpathian Foredeep, Czech Republic) has been inferred from 20 m of silt/siltstones, sand/sandstones and limestones penetrated by the Brus-1 borehole. Detailed multiproxy lithofacies and biofacies analyses have allowed facies and palaeoenvironment interpretations. The presence of molluscs, brachiopods and fish fauna, as well as large benthic and epiphytic foraminifera indicates a generally shallow, subtropical, marine environment. Despite the scarcity of biostratigraphical markers, the section can be correlated with the lowermost Badenian (~15–16 Ma). In the siltstones in the lower part of the borehole, there are abundant low-salinity foraminifera, which may indicate increased rainfall. Linked to this is the nutrient enrichment of the sea bottom water inferred from the presence of the high-nutrient taxa accompanied by abundant calcareous nannoplankton eutrophic taxa such as Coccolithus pelagicus and eutrophic planktonic foraminifera of the Globigerina bulloides/praebulloides group. The main Planostegina bloom was recorded in a sandstone in the interval 12.5–7 m, and was not influenced by a shift from high-organic content Valvulineria assemblage of small foraminifera to an epiphytic one. The boundary between siliciclastic and carbonate sedimentation (–7.5 m) shows a drop in K and Th concentrations, and in the Th/U ratio, but a rise in the Th/K ratio. This change in radioactive element content may generally indicate a significant decrease in terrestrial sediment input which is further supported by the onset of limestone deposition. Reversal of the deposition regime and a decrease of clastic input into the basin may be related to the changing of the precipitation regime, probably triggered by orbitally-forced cyclicity.

Trace Element Contents in Thyroid Cancer Investigated by Instrumental Neutron Activation Analysis

Background: Thyroid cancer is an internationally important health problem. The aim of this exploratory study was to evaluate whether significant changes in the thyroid tissue levels of Ag, Co, Cr, Fe, Hg, Rb, Sb, Sc, Se, and Zn exist in the malignantly transformed thyroid. Methods: Thyroid tissue levels of ten trace elements were prospectively evaluated in 41 patients with thyroid malignant tumors and 105 healthy inhabitants. Measurements were performed using non-destructive instrumental neutron activation analysis with high resolution spectrometry of long-lived radionuclides. Tissue samples were divided into two portions. One was used for morphological study while the other was intended for trace element analysis. Results: It was found that contents of Ag, Co, Cr, Hg, and Rb were significantly higher (approximately 12.8, 1.4, 1.6, 19.6, and 1.7 times, respectively) in cancerous tissues than in normal tissues. Conclusions: There are considerable changes in trace element contents in the malignantly transformed tissue of thyroid.

Source of Ca, Cd, Cu, Fe, K, Mg, Mn, Mo and Zn in grains of sunflower (Helianthus annuus) grown in nutrient solution: root uptake or remobilization from vegetative organs?

This study investigated the possible source organs delivering several trace elements to seeds (root uptake versus net remobilization), by studying changes in biomass and element contents in the plant organs. Sunflowers were grown in a greenhouse using a nutrient solution enriched with Cd. Four samplings were performed from the early flowering to the seeds physiological maturity. The low grain Ca indicated that phloem was likely the main route for transporting the elements to seeds. Excluding roots, the mass balance of the elements indicated the following contribution of the net remobilization to the total quantities in seeds at maturity: Mg = 50%, Cd = 14%, Cu = 35%, Fe = 29%, Mn = 19%, Zn = 12%. Source organs were mainly the receptacle and the stem. No significant net remobilization was observed for Ca, K and Mo. The amount of trace elements accumulated in vegetative parts can be redistributed to seeds in an extent that depended on the element. Due to the important contribution of root uptake to the content in seeds at maturity, the availability of elements in soil during the reproductive stages is an important point to consider.

CHARACTERISTICS OF Al-Fe SINTERS MADE BY THE POWDER METALLURGY ROUTE

The Al/Fe material was prepared by the powder metallurgy route with an additional intermediate stage which was a centrifuge of powder mixture. The application of the centrifuge stage was applied to obtain circular phase distribution of Al-rich phases in a sintered material. Iron powder with a particle size under 100 μm and aluminum powder with a particle size of about 25 μm, were used as starting materials. To determine the effect of centrifuging time on the distribution of Fe-Al particles, scanning electron microscopy (SEM, EDS) and XRD techniques were used. Microstructure observations show the influence of the centrifuging time on the distribution of Fe particles. It was observed that a longer centrifuging time caused changes in the ratio concentration of elements and allowed the growth of the intermetallic phase at the interface between solid Al and Fe particles.

Trace Element Contents in Thyroid Cancer Investigated by Energy Dispersive X-Ray Fluorescent Analysis

Background: Thyroid cancer is an internationally important health problem. The aim of this exploratory study was to evaluate whether significant changes in the thyroid tissue levels of Br, Cu, Fe, Rb, Sr, and Zn exist in the malignantly transformed thyroid. Methods: Thyroid tissue levels of six trace elements (Br, Cu, Fe, Rb, Sr, and Zn) were prospectively evaluated in 41 patients with thyroid malignant tumors and 105 healthy inhabitants. Measurements were performed using 109Cd radionuclide-induced energy-dispersive X-ray fluorescent analysis Tissue samples were divided into two portions. One was used for morphological study while the other was intended for trace element analysis. Results: It was found that contents of Br, Cu, and Rb were significantly higher (approximately 10, 3.4, and 1.4 times, respectively) and content of Zn were slightly, but significantly, lower (25%) in cancerous tissues than in normal tissues. Conclusions: There are considerable changes in trace element contents in the malignantly transformed tissue of thyroid.

Element content, growth and metabolic changes in Cu- and Cd- stressed Phaseolus vulgaris plants

A large-scale pot experiment was accomplished for investigation of the varied effects of different concentrations of Cu and Cd on certain growth and metabolic attributes of roots and shoots of Phaseolus vulgaris plants, over a period of three weeks. Plants supplemented with Cu and Cd at the concentrations of 10-6 and 10-3 M, showed increased levels of Cu and Cd in both shoots and roots, above those levels in controls. However, Cu or Cd accumulation was lower in shoots than in roots. As compared with control levels, the low (10-6 M) concentration of Cu induced either a significant or an insignificant increase in growth parameters, photosynthetic pigments, PS II activity, glucose, proline and glycine contents in both roots and shoots. Otherwise, insignificant decreases in fructose, sucrose, polysaccharides, total saccharides, total soluble-N, protein –N, DNA and RNA contents, in the same test plant parts, were obtained. A reverse situation was however observed with the high concentration (10-3 M) of Cu as well as with the low and high concentrations (10-3 and 10-6 M) of Cd. In general, the observed adverse effects were more pronounced with Cd at (10-6 M) as compared with those maintained with Cu at the same concentration. Furthermore, the most detrimental adverse effects were apparent upon administration of the high (10-3 M) concentration of Cd. The prominence of the above mentioned changes in growth and metabolism to stress tolerance in common bean is discussed.

Bioinorganic chemical composition of the lens and methods of its investigation

Bioinorganic chemical composition of the lens of human and experimental animals (cows, dogs, rats, rabbits) have been analyzed in various studies. In most cases, the studies employed different methods to determine the gross (total) composition of chemical elements and their concentrations in the examined samples. Less frequently, they included an assessment of the distribution of chemical elements in the lens and correlation of their concentration with its morphological changes. Chemical elements from all groups (series) of the periodic classification system were discovered in the lens substance. Despite similar investigation methods, different authors obtained contradicting results on the chemical composition of the lens. This article presents data suggesting possible correlation between inorganic chemical elements in the lens substance with the development and formation of lenticular opacities. All currently employed methods are known to only analyze limited number of select chemical elements in the tissues and do not consider the whole range of elements that can be analyzed with existing technology; furthermore, the majority of studies are conducted on the animal model lens. Therefore, it is feasible to continue the development of the chemical microanalysis method by increasing the sensitivity of Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS) with the purpose of assessing the gross chemical composition and distribution of the elements in the lens substance, as well as revealing possible correlation between element concentration and morphological changes in the lens.

Early Cretaceous high-Ti and low-Ti mafic magmatism in Southeastern Tibet: Insights into magmatic evolution of the Comei Large Igneous Province

The Dala diabase intrusion, at the southeastern margin of the Yardoi gneiss dome, is located within the outcrop area of the ~132Ma Comei Large Igneous Province (LIP), the result of initial activity of the Kerguelen plume. We present new zircon U-Pb geochronology results to show that the Dala diabase was emplaced at ~132Ma and geochemical data (whole-rock element and Sr-Nd isotope ratios, zircon Hf isotopes and Fe-Ti oxide mineral chemistry) to confirm that the Dala diabase intrusion is part of the Comei LIP. The Dala diabase can be divided into a high-Mg/low-Ti series and a low-Mg/high-Ti series. The high-Mg/low-Ti series represents more primitive mafic magma compositions that we demonstrate are parental to the low-Mg/high-Ti series. Fractionation of olivine and clinopyroxene, followed by plagioclase within the low-Mg series, lead to systematic changes in concentrations of mantle compatible elements (Cr, Co, Ni, and V), REEs, HFSEs, and major elements such as Ti and P. Some Dala samples from the low-Mg/high-Ti series contain large ilmenite clusters and show extreme enrichment of Ti with elevated Ti/Y ratios, likely due to settling and accumulation of ilmenite during the magma chamber evolution. However, most samples from throughout the Comei LIP follow the Ti-evolution trend of the typical liquid line of descent (LLD) of primary OIB compositions, showing strong evidence of control of Ti contents by differentiation processes. In many other localities, however, primitive magmas are absent and observed Ti contents of evolved magmas cannot be quantitatively related to source processes. Careful examination of the petrogenetic relationship between co-existing low-Ti and high-Ti mafic rocks is essential to using observed rock chemistry to infer source composition, location, and degree of melting.

Scarce Occurrence of Calcification in Human Sinoatrial Nodal Arteries in Old Age.

To elucidate age-related changes of the sinoatrial (sinuatrial) nodal (SAN) artery, the authors investigated age-related changes of elements in the SAN artery by direct chemical analysis. In addition, the effects of different arterial origins, arterial sizes, and genders on element accumulation were investigated in the SAN artery. Fifty-nine formalin-fixed adult Thai hearts were dissected, and the following three types of the SAN artery were found: The first type was a single SAN artery arising from the right coronary artery (RCA). The second type was a single SAN artery arising from the proximal segment of the left circumflex artery (LCX). The third type was dual SAN artery arising from both the RCA and the LCX. For element analysis, both 41 single SAN arteries arising from the RCA and the LCX and 18 larger branches of dual SAN artery were used. After the arteries were incinerated with nitric acid and perchloric acid, element contents were determined by inductively coupled plasma-atomic emission spectrometry. It was found that seven element contents such as Ca, P, S, Mg, Zn, Fe, and Na did not change significantly in the SAN arteries with aging. Regarding the relationships among seven elements in the SAN arteries, extremely significant direct correlations were found among P, S, Mg, and Fe contents with one exception. However, no significant correlations were found between Ca and either P or Mg contents in the SAN arteries. To examine an effect of the different arterial origins on element accumulation, the SAN arteries were separated into the RCA and the LCX groups by the arterial origin and age-related changes of element contents were compared between two groups. It was found that there were no significant differences between the RCA and the LCX groups in age-related changes of Ca and P contents. No gender differences were found in age-related changes of Ca and P contents in the SAN arteries. To elucidate whether calcification occurred in the SAN arteries in old age, both the mass ratios of Ca/P and Mg/Ca were estimated in the SAN arteries. The mass ratio of Ca/P increased progressively in the SAN arteries with Ca increase, being not constant. The mass ratio of Mg/Ca decreased gradually in the SAN arteries with Ca increase, but the average mass ratio of Mg/Ca was very high, being 49.4±16.5%. These results indicated that calcification scarcely occurred in the SAN arteries in old age, independently of the arterial origin and gender.

Changes in Inorganic Element Concentrations of Drained Nutrient Solution and Leaves in Compliance with Numerical Increment of Fruiting Node during Hydroponic Cultivation of Cherry Tomato

Changes in Inorganic Element Concentrations of Drained Nutrient Solution and Leaves in Compliance with Numerical Increment of Fruiting Node during Hydroponic Cultivation of Cherry Tomato

Element content of Yemeni honeys as a long-time marker to ascertain honey botanical origin and quality

This work was aimed at studying variations in the element content of five famous Yemeni honeys of different floral origin. For this purpose, samples of honey were collected over three years from four mono-floral and one multi-floral honey. Element levels were determined by ICP-AES. Results show a highly reproducible level of element for each honey type and a significant change in element content in honey as a function of the floral source. In addition to demonstrating the impact of the floral origin on Yemeni-honey mineral content, our compiled values will be highly useful to ascertain honey quality once Yemen will return to less-trouble times.

Strontium isotope fractionation during strontianite (SrCO3) dissolution, precipitation and at equilibrium

In this study we examine the behavior of stable Sr isotopes between strontianite [SrCO3] and reactive fluid during mineral dissolution, precipitation, and at chemical equilibrium. Experiments were performed in batch reactors at 25°C in 0.01M NaCl solutions wherein the pH was adjusted by bubbling of a water saturated gas phase of pure CO2 or atmospheric air. The equilibrium Sr isotope fractionation between strontianite and fluid after dissolution of the solid under 1atm CO2 atmosphere was estimated as Δ88/86SrSrCO3-fluid = δ88/86Sr SrCO3−δ88/86Srfluid=−0.05±0.01‰. On the other hand, during strontianite precipitation, an enrichment of the fluid phase in 88Sr, the heavy isotopomer, was observed. The evolution of the δ88/86Srfluid during strontianite precipitation can be modeled using a Rayleigh distillation approach and the estimated, kinetically driven, fractionation factor αSrCO3-fluid between solid and fluid is calculated to be 0.99985±0.00003 corresponding to Δ88/86SrSrCO3-fluid = −0.15‰. The obtained results further support that under chemical equilibrium conditions between solid and fluid a continuous exchange of isotopes occurs until the system approaches isotopic equilibrium. This isotopic exchange is not limited to the outer surface layer of the strontianite crystal, but extends to ∼7–8 unit cells below the crystal surface. The behavior of Sr isotopes in this study is in excellent agreement with the concept of dynamic equilibrium and it suggests that the time needed for achievement of chemical equilibrium is generally shorter compared to that for isotopic equilibrium. Thus it is suggested that in natural Sr-bearing carbonates an isotopic change may still occur close to thermodynamic equilibrium, despite no observable change in aqueous elemental concentrations. As such, a secondary and ongoing change of Sr isotope signals in carbonate minerals caused by isotopic re-equilibration with fluids has to be considered in order to use Sr isotopes as environmental proxies in aquatic environments.

Short- and long-term exposure to imidacloprid disturbs the elemental composition and free amino acid profile in muscles of Labeo rohita

Imidacloprid [1-(6-chloro-3-pyridylmethyl)-N-nitro-imidazolidin-2-ylideneamine] is among the most extensively used pesticide in Pakistan. The aim of this investigation was to report the changes in concentration of different elements and amino acid in the muscle of Labeo rohita upon imidacloprid exposure. Juvenile Labeo rohita (N = 480) were treated with 120mgL−1 imidacloprid under short and long-term experimental conditions. At the end of each experiment, fish muscle was used for elemental concentration (determination by an atomic absorption spectrophotometer) and amino acid estimation (by high-performance liquid chromatography (HPLC)). Our results indicated that sodium, potassium, calcium, magnesium, iron, aluminum, and lead concentrations were significantly different (P < 0.05) when compared between imidacloprid-treated and untreated L. rohita and changes were more pronounced in short-term experimental groups. HPLC-generated data analysis showed that proline, isoleucine, and glycine concentrations increased while the levels of phenylalanine, alanine, and leucine decreased significantly (P < 0.05) in muscles of fish exposed to imidacloprid under short-term conditions. On the other hand, serine, arginine, and glycine increased significantly and alanine decreased significantly in L. rohita exposed to pesticide under long-term experimental conditions. It is concluded that imidacloprid (120 mg L−1) exposure to L. rohita for a variable duration has significantly changed the elemental composition and studied amino acid concentrations in fish muscles making it unsuitable for human consumption.

Detecting changes of soil environmental parameters by statistics and GIS: A case from the lower Changjiang plain, China

The changes of the important soil environmental parameters in the lower Changjiang plain were investigated by means of statistics and geographical information system (GIS) using data from a soil survey carried out in 2004 and 150 samples collected in 2014. Box plots and the t-test were used to detect changes in parameters and/or elemental concentrations. An increasing trend of total organic carbon (TOC), N, P, Cd, Pb, and Se concentrations was found with the decrease of soil pH and As concentration. Compositional errors induced by sampling and analysis were assessed by the nugget value (C0) based on semi-variogram as the basis of change detection of the spatial variables. We found that the variables near normal distributions are suitable to denote their changes spatially by the differences (minus) of the two dates' data, while their ratios (division) or the log transformed differences, are expected to be used for those near log-normal distributions. The study area has the problem of soil acidification with the pH decrease of ~8.6%, and increasing heavy metal pollutions with medians of Cd and Pb concentrations increased by 18.2% and 6.9% respectively. Soil fertility has been improved with TOC, N, and P concentrations increased by ~42.8%, ~16.9%, and ~13.4% respectively. However, soil arsenic (As) has a trend of depletion with the median of its concentration decreased by 11.0%.

Chemostratigraphic insights into fluvio-lacustrine deposition, Yanchang Formation, Upper Triassic, Ordos Basin, China

A chemostratigraphic study of a 300 m long core recovered from the southeastern central Ordos depocenter reveals thick ([Formula: see text]) intervals of fine-grained, organic-rich lacustrine strata, interpreted to represent deepwater deposition under meromictic conditions (incomplete watermass overturn) during lake highstand phases, interspersed with thick (10–30 m) intervals of arkosic sandstones, reflective of fluvio-deltaic deposition during lake lowstand phases. Along with elevated concentrations of %Al, traditionally a proxy for clay content, maximum total-organic-carbon (TOC) values in the deepwater lacustrine facies reach 8%, with average values of approximately 3%. The fine-grained, organic-rich facies is also characterized by elevated S (up to 6%) and As concentrations, both proxies for pyrite, an indicator of more stagnant, reducing conditions in the hypolimnion (the volume of the lake below the surface mixing zone) during lake highstand phases. Enrichment factors for redox-sensitive trace elements (RSTEs) are not significantly elevated throughout the TOC-rich intervals, but they are punctuated in thinner intervals. Punctuated enrichments in RSTEs reflect episodes of enhanced suboxia/anoxia in the hypolimnion during lake highstand phases resulting from sustained meromixis (protracted episodes of incomplete watermass turnover). Although dramatic shifts between fluvio-deltaic and deepwater lacustrine deposition are recorded in the Yanchang strata, no evidence indicates that the lacustrine system ever built up a significant salt concentration, suggesting that an outlet was maintained throughout much of the depositional history. A chemofacies framework for the Yanchang Formation is developed based on hierarchical cluster analysis and ranking of major element chemostratigraphic results. The outcome of chemofacies analysis is similar to the lithofacies analysis, subdividing the stratigraphic record of calcite-cemented sandstone/siltstone lithologies (fluvio-deltaic facies) and silty to finer grained mudstone lithologies (deep-water lacustrine facies) based on changes in elemental concentrations that equate to shifts in the relative abundance of mineral contents (e.g., clays, quartz, feldspars, pyrite, and carbonates).

Effects of sewage sludge compost on the growth and element uptake of Neolamarckia cadamba seedlings

Sewage sludge compost (SSC) is rich in organic matter and nutrient elements indispensable to plant growth. Utilizing SSC as seedling growing substrate is generally recognized as a new ecological method for utilization of sewage sludge. We investigated impacts of SSC treatments including 0% (CK), 25% (T1), 50% (T2), 75% (T3), and 100% (T4) on the growth and nutrient uptake of Neolamarckia cadamba seedlings in a 7-month pot experiment. The changes in element contents in substrate after pot experiment were also addressed. Results showed the SSC treatments had significant impacts on the growth of N. cadamba seedlings. The seedlings in T4 treatment grew abnormally and all died in two weeks after transplanting. Seedling height, ground diameter and biomass in T1, T2 and T3 treatments were significantly higher than CK, with those in T2 being the best among all treatments. Seedlings in T2 and T3 treatments took up significantly more N, P, K, Cu, Zn, Pb and Cd, while those in T1 treatment absorbed significantly more N and Pb than CK. The heavy metal uptake amount of each treatment exhibited the order of Zn＞Cu＞Pb＞Cd. At the end of the pot experiment, the contents of organic matter, N, P and K in growing substrate were still relatively high, and a certain portion of heavy metals still remained in the substrate, but with lower contents than the standards set for agricultural usage-oriented sewage sludge, indicating that the post-experiment substrate may be reused.

Origin of the volcanic rocks erupted in the eastern Manus Basin: Basaltic andesite-andesite-dacite associations

There has been much recent interest in the origin of intermediate lava and several hypotheses are: 1) direct melting of the mantle under water-saturated conditions, 2) partial melting of altered crust, 3) fractional crystallization of parent magma, and 4) magma mixing of mafic magmas with dacitic/rhyolitic magmas. Volcanic rocks series ranging from basaltic andesite to dacite (SiO2 ranges from 53.8 to 63.0 wt.%) from the eastern Manus Basin were detected for major and trace element compositions to understand their origin. Low H2O contents, positive correlations of La-SiO2 and Yb-SiO2, oxygen isotope data and the indistinct change of trace element concentrations in oscillatory zoning of plagioclase phenocrysts rule out the models in which silicic lava results from direct melting of hydrous mantle, partial melting of altered oceanic crust or gabbros, and magma mixing, respectively. Besides, the geochemical data of whole rock and melt inclusions indicate that fractional crystallization plays a dominant role in generating the intermediate lava with subduction features.

CO2-Induced Changes in Wheat Grain Composition: Meta-Analysis and Response Functions

Elevated carbon dioxide (eCO2) stimulates wheat grain yield, but simultaneously reduces protein/nitrogen (N) concentration. Also, other essential nutrients are subject to change. This study is a synthesis of wheat experiments with eCO2, estimating the effects on N, minerals (B, Ca, Cd, Fe, K, Mg, Mn, Na, P, S, Zn), and starch. The analysis was performed by (i) deriving response functions to assess the gradual change in element concentration with increasing CO2 concentration, (ii) meta-analysis to test the average magnitude and significance of observed effects, and (iii) relating CO2 effects on minerals to effects on N and grain yield. Responses ranged from zero to strong negative effects of eCO2 on mineral concentration, with the largest reductions for the nutritionally important elements of N, Fe, S, Zn, and Mg. Together with the positive but small and non-significant effect on starch concentration, the large variation in effects suggests that CO2-induced responses cannot be explained only by a simple dilution model. To explain the observed pattern, uptake and transport mechanisms may have to be considered, along with the link of different elements to N uptake. Our study shows that eCO2 has a significant effect on wheat grain stoichiometry, with implications for human nutrition in a world of rising CO2.

Environmental Geochemistry of Mine Tailings Soils in the Artisanal Gold Mining District of Betare -Oya, Cameroon

Changes in trace element concentrations in mine tailings (dry and wet) were investigated in the gold mining area of Bétaré-Oya, Eastern Cameroon. Forty-one surface sediment samples were analyzed using ICP-MS for heavy metals and pollution was assessed using Enrichment Ratio and Geo Accumulation Index (Igeo); using a sample from a remote area as control.Trace elements in mine tailings show significant increase compared to the background (control) values, with the exception of Sr and Nb. It is suggested that allochtonous deposition may account for Sr distribution. A strong correlation is observed between the lithophile elements; Y, Nb, Ce, La, and Pb. Their association with each other is also strong, i.e. Nb/Ce (.73) and La/Ce (.63). The close association of these elements in the samples may be an indication of the effect of resistant heavy minerals from felsic rocks (mainly granites and gneisses). Cu, Zn, Sr and Ba distribution is associated with mineralisation of sulphide-bearing minerals and clay formation from weathering of mica schist. Cu, Zn, As, W, Mo and Ag have been identified as potential pollutants. Compared to the Dutch soil quality guidelines, these elements are above the target values and below the intervention levels. Arsenic is considered to be the most threatening element, with regards to its potency. The distribution of As in this area appears to be controlled by mining activities.

Matrix Effects in Quantitative Analysis of Laser-Induced Breakdown Spectroscopy (LIBS) of Rock Powders Doped with Cr, Mn, Ni, Zn, and Co.

Obtaining quantitative chemical information using laser-induced breakdown spectroscopy is challenging due to the variability in the bulk composition of geological materials. Chemical matrix effects caused by this variability produce changes in the peak area that are not proportional to the changes in minor element concentration. Therefore the use of univariate calibrations to predict trace element concentrations in geological samples is plagued by a high degree of uncertainty. This work evaluated the accuracy of univariate minor element predictions as a function of the composition of the major element matrices of the samples and examined the factors that limit the prediction accuracy of univariate calibrations. Five different sample matrices were doped with 10-85 000 ppm Cr, Mn, Ni, Zn, and Co and then independently measured in 175 mixtures by X-ray fluorescence, inductively coupled plasma atomic emission spectrometry, and laser-induced breakdown spectroscopy, the latter at three different laser energies (1.9, 2.8, and 3.7 mJ). Univariate prediction models for minor element concentrations were created using varying combinations of dopants, matrices, normalization/no normalization, and energy density; the model accuracies were evaluated using root mean square prediction errors and leave-one-out cross-validation. The results showed the superiority of using normalization for predictions of minor elements when the predicted sample and those in the training set had matrices with similar SiO2 contents. Normalization also mitigates differences in spectra arising from laser/sample coupling effects and the use of different energy densities. Prediction of minor elements in matrices that are dissimilar to those in the training set can increase the uncertainty of prediction by an order of magnitude. Overall, the quality of a univariate calibration is primarily determined by the availability of a persistent, measurable peak with a favorable transition probability that has little to no interference from neighboring peaks in the spectra of both the unknown and those used to train it.