Reference Soil Samples Research Articles

Sensitivity and energy resolution of the Balqarad clover detector

Abstract This study investigates operational modes and veto techniques using the Balqarad clover system, focusing on energy resolution parameters like Full Width at Half Maximum (FWHM) and Full Width at Tenth Maximum (FWTM). Comparing with the GAMMA-X detector, clover consistently shows lower FWHM values (e.g., 1.08 keV vs. 1.45 keV for 133Ba), highlighting its higher precision. The clover system also achieves lower Minimum Detectable Activity (MDA) values (ranging from 1.19 to 1.56 Bq for 60Co and 137Cs in direct and addback modes), underscoring its enhanced performance compared to literature data. Practical MDA calculations using a reference soil sample reinforce the advantage of addback mode over direct mode in achieving more accurate measurements. These findings stress the critical importance of selecting the right measurement system for precise applications like radiation monitoring and nuclear safety assessments.

Measurement of ultra-trace level 237Np in soil and sediment by triple-quadrupole inductively coupled plasma-mass spectrometry with different mass modes combined with chemical separation

Long-lived trans‑uranium nuclides such as 237Np, may reside in the environment for long period and result in ecological impact and human health threat. Accurate measurement of 237Np in the environment is important for the risk assessment and ecological evaluation. However, the spectral peak tailing and polyatomic ions interference greatly limit the measurement of 237Np with triple quadrupole ICP-MS (ICP-MS/MS), which have been successfully used for analysis of ultra-trace level 239,240Pu and 241Am. The novel methods for 237Np measurement with ICP-MS/MS in both on-mass and mass-shift modes were examined in this paper. When helium was used as the collision gas for the ICP-MS/MS measurement with on-mass mode, the interference contribution to the counts for 237Np (at m/z 237) as low as 4 × 10−8 was observed only from Hg, while no measurable interference from Tl and Pb was observed. Moreover, when the mass-shift mode is employed with O2/He and He as the collision/reaction gas, the interference contributions from Hg, Tl and Pb were all negligible. The detection limit of 237Np was reduced to 0.014 fg/g and 0.019 fg/g for on-mass and mass-shift mode, respectively. The novel methods were demonstrated to enable accurate determination of 1.0 fg/g level 237Np in the emulated sample solutions with a 237Np/238U atomic ratio as low as 10−9. Combined with appropriate chemical separation procedure, the developed methods were verified with certified reference materials and soil samples.

In vitro bioaccessibility round robin testing for arsenic and lead in standard reference materials and soil samples.

In this study, we assessed the suitability of using a standard reference material (SRM) other than National Institute of Standards and Technology (NIST) 2710a or NIST 2711a in USEPA Method 1340 to determine arsenic (As) and lead (Pb) in vitro bioaccessibility (IVBA) and the capabilities of Canadian-based laboratories to perform the method. Five laboratories participated in an initial round robin study and analyzed NIST 2710a, NIST 2711a, BGS119, and Enviromat SS-2. Intra- and inter-laboratory variability were generally acceptable with percentage relative standard deviations (RSD) of less than 20%. The mean total As and Pb concentrations obtained for BGS119 (332 and 936 mg/kg, respectively) and the mean IVBA values (As = 14.3% and Pb = 78.1%) suggested it may be a suitable and acceptable SRM, whereas the concentration of As in Enviromat SS-2 as received (3.2 mg/kg) was deemed too low. Ten soil samples from sites with varying land use were analyzed in a follow-up round robin study using the modified IVBA method that included BGS119 as SRM. The concentrations of As and Pb in the IVBA extracts reported by the participating laboratories were comparable. The mean As IVBA values for the field-collected samples ranged from 0.1% to 56.4%; for Pb, they ranged from 7.0% to 121%. The lowest IVBA values were measured in mine site samples; the highest values were associated with smelter-affected soils. The low IVBA values correlated with high iron content. Intra- and interlaboratory reproducibility were acceptable (RSD < 30%). Based on the findings of the study, laboratories can use the modified method to provide reproducible and comparable As and Pb IVBA data. The use of BGS119 as an alternative SRM to assess contaminated sites in the province of British Columbia for regulatory purposes is recommended, as it is representative of As and Pb concentrations in contaminated soils in British Columbia. Integr Environ Assess Manag 2024;20:1486-1495. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Metals Contained in Various Formulations of Mineral Nitrogen Fertilizers Determined Using Portable X-ray Fluorescence

According to the Scopus database, over the last five years, 91 scientific papers with the keyword “pXRF” (portable X-ray fluorescence) were published in indexed journals in the domain of environmental science and agricultural science, which indicates more frequent applications of this technique in scientific research. The pXRF method is characterized by speed, precision, accuracy, and the possibility of a simultaneous analysis of a large number of elements, albeit with higher limits of detection (LODs) as a major disadvantage. The presence of metals in certain phosphate fertilizers is well established, though not to the same extent as in mineral nitrogen fertilizers. The aim of this research was to determine the metal content (As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Si, Sr, Th, U, Zn, Zr, and Y) in thirteen commercial mineral nitrogen fertilizers via the pXRF method. Six straight fertilizers (ammonium nitrate, ammonium sulphate nitrate, limestone ammonium, nitrate, and urea) and seven complex fertilizers (various NPK formulations), which are different even according to their production technology, produced in Croatia were analyzed using the handheld Vanta C (Olympus) XRF analyzer according to the loose powder method and “point and shoot” technique. Data quality control was performed by analyzing the reference fertilizer samples and certified and reference soil samples. The results revealed that the determined contents of Cd, Mn, and Th were relatively higher in the single-component fertilizers, while the contents of As, Cr, Fe, Ni, Si, Sr, Zn, Zr, Y, and U were relatively higher in the complex fertilizers. Due to the higher LODs of Co and Pb (3 mg/kg) and Mo (2 mg/kg), the pXRF method was not appropriate for the determination of these metals in the analyzed fertilizers. The quantified metal content in the analyzed fertilizers varied as follows: 2.0–8.0 mg As/kg; 11.5–31.3 mg Cd/kg; 29.8–118.5 mg Cr/kg; 7.8–26.3 mg Cu/kg; 16.5–2209 mg Fe/kg; 20.3–5290 mg Mn/kg; 6.2–27.8 mg Ni/kg; 1156–4581 mg Si/kg; 2.0–469.8 mg Sr/kg; 3.0–35.3 mg Th/kg; 2.0–82.8 mg U/kg; 1.4–166 mg Zn/kg; 9.7–15.3 mg Zr/kg; and 16.5–128.0 mg Y/kg. The results indicated that the pXRF method is particularly suitable for measurement and metal detection in complex nitrogen mineral fertilizers with higher amounts of metals, but it is not suitable for the detection and quantification of the lower amounts of As, Zr, Y, Cu, Ni, and Cr in single-component nitrogen fertilizers. Compared to all of the investigated fertilizers, the highest amounts of As, Cr, Cu, Fe, Ni, U, Zn, and Zr were quantified in the NPK 7-20-30 formulation.

Comparison between Rock-Eval® and temperature-programmed pyrolysis/mass spectrometry for the analysis of environmental and geological samples

Natural organic matter (OM) has a complex structure whose complete structural and chemical description remains a challenge. Rock-Eval® device constitutes a rapid and affordable method for obtaining key quantitative and qualitative parameters on OM. Previous studies on soil samples proposed to deconvolute or to split into temperature slices Rock-Eval® S2 pyrograms in order to distinguish and quantify chemical fractions of increasing thermal lability. In order to provide support for such an assumption, this work proposes a methodological approach based on coupling a temperature-programmed pyrolyser to a standard mass spectrometer (Py-MS). In this manuscript, we compare results acquired by Rock-Eval® pyrolysis with those from Total Ion Current (TIC) traces obtained by Py-MS on a set of reference soil samples, completed by dissolved OM, source rock and coal samples, in order to test the extent to which this approach can be generalized. Our results show good quantitative and qualitative agreements between the two methods. This comparison is a prerequisite before going further and addressing the molecular significance of S2 pyrograms deconvolution through the examination of m/z fragments abundance curves.

Ultrasensitive determination of mercury by ICP-OES coupled with a vapor generation approach based on solution cathode glow discharge

We herein proposed a sample introduction technique based on solution cathode glow discharge (SCGD) of a portable design for inductively coupled plasma-optical emission spectrometry (ICP-OES) and its application in sensitive determination of mercury. The products from SCGD containing mercury vapor, were transported by an Ar flow to ICP spectrometer for detection. A gas liquid separator (GLS) and a dryer were used to condense and remove most of the accompanying moisture, which greatly improved both the stability and sensitivity of the signal. The detection limit (DL) acquired by this developed method was 0.22 µg/L (194.1 nm), which was nearly 82 times lower than that obtained by pneumatic nebulization (PN). The relative standard deviation (RSD) was 1.4% (n = 14) for a 50 µg/L standard. Blank solution (HNO3, pH 1) can effectively elute mercury residue. Its accuracy and practicality were also demonstrated by the determination of GBW10029 (fish) certified reference material, shrimp, crawfish, soil and human hair samples. The results showed good consistency with the certified values and the values obtained using inductively coupled plasma−mass spectrometry.

Direct prediction of site-specific lime requirement of arable fields using the base neutralizing capacity and a multi-sensor platform for on-the-go soil mapping

Liming agricultural fields is necessary for counteracting soil acidity and is one of the oldest operations in soil fertility management. However, the best management practice for liming in Germany only insufficiently considers within-field soil variability. Thus, a site-specific variable rate liming strategy was developed and tested on nine agricultural fields in a quaternary landscape of north-east Germany. It is based on the use of a proximal soil sensing module using potentiometric, geoelectric and optical sensors that have been found to be proxies for soil pH, texture and soil organic matter (SOM), which are the most relevant lime requirement (LR) affecting soil parameters. These were compared to laboratory LR analysis of reference soil samples using the soil’s base neutralizing capacity (BNC). Sensor data fusion utilizing stepwise multi-variate linear regression (MLR) analysis was used to predict BNC-based LR (LRBNC) for each field. The MLR models achieved high adjusted R2 values between 0.70 and 0.91 and low RMSE values from 65 to 204 kg CaCO3 ha−1. In comparison to univariate modeling, MLR models improved prediction by 3 to 27% with 9% improvement on average. The relative importance of covariates in the field-specific prediction models were quantified by computing standardized regression coefficients (SRC). The importance of covariates varied between fields, which emphasizes the necessity of a field-specific calibration of proximal sensor data. However, soil pH was the most important parameter for LR determination of the soils studied. Geostatistical semivariance analysis revealed differences between fields in the spatial variability of LRBNC. The sill-to-range ratio (SRR) was used to quantify and compare spatial LRBNC variability of the nine test fields. Finally, high resolution LR maps were generated. The BNC-based LR method also produces negative LR values for soil samples with pH values above which lime is required. Hence, the LR maps additionally provide an estimate on the quantity of chemically acidifying fertilizers that can be applied to obtain an optimal soil pH value.

X-ray fluorescence spectroscopic analysis of trace elements in soil with an Adaboost back propagation neural network and multivariate-partial least squares regression

Poisonous elements such as lead (Pb), arsenic (As), cadmium (Cd), and chromium (Cr) are commonly observed in polluted soil but hard to detect due to low concentration. Currently, the quantitative content of elements can be determined by an x-ray fluorescence (XRF) analyzer if the limit of detection (LOD) is known. However, to ensure that elements with extremely low content can be detected, the LOD needs to be reduced and determined. Firstly, the authors utilized the traditional method detection limit (MDL) formula to calculate the LOD for benchmark purposes. Secondly, in order to improve the signal to noise ratios of the characteristic peaks, the wavelet threshold denoising method and iterative discrete wavelet transform algorithm were utilized for spectral denoising and background noises deduction of XRF spectra based on 57 certified reference soil samples. Thirdly, a novel Adaboost back propagation neural network model was proposed to reduce and determine the values of LOD. The results showed that the LODs of trace elements determined from the proposed algorithm decreased greatly compared to the traditional MDL method. Finally, the calibration curve of elemental concentration versus counting rate was established and regressed using the proposed multivariate partial least squares model. The goodness of fit (R 2) was significantly increased. Therefore, the proposed algorithm is effective to determine the LOD and can yield optimal performance in instrument calibration of trace elements in soil.

Micrometeorological conditions of the soloteca of Embrapa Solos -Rio de Janeiro, Brazil

Soloteca is the term used in Brazil to refer to the place where reference soil samples are stored. The Soloteca of Embrapa Solos-RJ, for example, stores soil samples from different regions of Brazil, and these samples need to be stored in conditions that preserve their intrinsic characteristics. In this context, the objective of this work was to determine the air temperature and relative humidity conditions in the Soloteca of Embrapa Solos-RJ. The data were collected by three Thermo hygrometers, installed inside and outside the place where the samples are stored, in the period from December 1, 2016, to March 31, 2017, corresponding to summer 2016/17. The difference between the mean and variance of the data for each environment/height was evaluated at the 5% level, respectively, by the t-Student and Snedecor's F tests. The other statistical analyses were presented by boxplots. It was observed that the air temperature, on average, did not differ between the indoor and outdoor environments at a height of 1.6 meters, but there was a difference with the sensor installed near the surface (0.5 meters). On the other hand, the dispersion of the data attested by the variance and the coefficient of variation in the external environment was greater than those recorded internally.

Calibration methods for measuring the color of moist soils with digital cameras

The study of soil color is important for soil classification and as a diagnostic criterion reflecting a range of soil processes and soil properties. Field measurements of soil colors are affected by moisture content and other environmental and lighting condition. Here we evaluated calibration procedures to obtain colorimetrically corrected soil profile images on field moist soils using a gray card or histogram of reference soil images. In the laboratory, we further evaluated the colorimetric calibration methods on moist soil samples with varying moisture content and texture using an external scale (color scale with air-dry soil standards with known colors) or an internal scale (moist reference soil samples). The colors measured by a spectrometer were used as true colors of moist soil samples. The CIE L*a*b* color difference (ΔEab*) was used to evaluate the colorimetric accuracy between colors obtained from different devices. The results showed that the soil colors were greatly affected by soil moisture content. With the decrease in soil moisture, a significant increase in lightness (L*) and yellowness (b*) was observed. The field experiment showed that the colorimetrically accurate soil profile images at natural moist condition cannot be obtained by calibrating the digital image using a gray card or using the image of another camera. The laboratory experiments showed that colorimetrically accurate images can be obtained for sandy loam soil at a moisture content of less than 12% using the external standard. For soils with different texture, color characteristics, and moisture content (5–40%), colorimetrically accurate images of the samples can be obtained by using the internal scale. We conclude that the proposed calibration methods can be used to obtain colors of moist soils.

Steroids aid in human decomposition fluid identification in soils of temporary mass graves from World War II

Steroids are widely used for the detection of faecal matter and also – in recent years – for characterising human decomposition in the terrestrial environment. Until now it was not clear whether all commonly used faecal (i.e. 5β-stanols, 5β-stanones and bile acids) and tissue derived steroids (i.e. cholesterol, 5α-cholestanol and 5α-cholestanone) could reveal the presence of human decomposition products in temporary graves. In this study, soil was sampled from three putative mass graves where concentration camp prisoners were temporarily buried for 10 months at the end of World War II (1944 – 45). We hypothesised that soil from the putative temporary mass graves exhibits elevated concentrations of faecal and tissue steroids compared to reference samples, thereby reflecting the former input of human decomposition products. Steroids (Δ5-sterols, 5β-stanols, 5α-stanols, stanones and bile acids) from soil samples from three soil pits suspected to be putative mass graves, as well as reference soil samples, were extracted and analysed with gas chromatography-mass spectrometry (GC–MS). Cholesterol, 5α-cholestanol and 5α-cholestanone were ubiquitously present in all soil pits and reference samples and therefore not indicative for the former input of human decomposition products. Compared to the reference, increased concentrations of selected faecal steroids (coprostanol, 5β-stigmastanol, 5β-cholestanone, lithocholic acid, isolithocholic acid) provided a strong indication of the former input of human decomposition products for one soil pit (pit 2). Additionally, epicoprostanol and isolithocholic acid were unique components for soil pit 2 as they were found neither in the other pits nor in the reference soil. In combination with earlier findings, steroid and bile acid patterns indicate an input of faecal and tissue constituents from former buried bodies in at least one of the three soil pits.

Study of the influence of chemical anti-icing materials on frost heaving of the roadbed soils

This work examines the influence of chemical anti-icing materials on the frost resistance of the road pavement. Methods and technologies for introducing salt additives into the soil are considered. The preparation of soil with salt additives for testing for frost heaving is described. The kinetics of frost heaving processes of the reference soil sample and soil treated with salt additives was investigated. The influence of type and concentration of the salt additive on the degree of frost heaving of soils was investigated. The negative impact of chemical anti-icing additives on the indicators of frost heaving of soils, especially with uneven salinity, was registered.

Potential of Bacopa monnieri (L.) Wettst and Sesuvium verrucosum Raf. as an agronomic management alternative to recover the productivity of saline soils

Water scarcity and increasing salinity are the main limiting environmental factors directly affecting the establishment and development of agroecosystems. The objective of this study was to assess the capacity of the halophytes Bacopa monnieri (L.) Wettst and Sesuvium verrucosum Raf., to improve the chemical properties of a saline soil during a 240-day period in the field so as to subsequently examine their potential to associate with Zea mays in the previously desalinated surface. The treatments proposed were [T1 (reference soil sample), T2 (soil + B. monnieri), T3 (soil + S. verrucosum), and T4 (soil + B. monnieri + S. verrucosum)]. The results showed that the association of the species B monnieri and S. verrucosum has the potential to enhance the chemical characteristics of the severely saline and clayey soil, showing ECe reductions of 11.13–7.97 dS/m and pH of 7.84–7.42, as well as increase in soil porosity from 54.71% to 57.23%. It was also found that the association of these plants have a phytodesalination capacity of 1.21 t Na+ ha−1, this served to prepare the conditions for the growth of the Z. mays and generate yields of 8.5 t ha−1.

Direct photoimmobilization of extraction disks on “green state” 3D printed devices

Post-curing is essential to improve the mechanical properties of 3D printed parts fabricated by stereolithography (SLA), since right after 3D printing they remain in a “green state”. It means that the 3D printed parts have reached their final shape, but the polymerization reaction has not been yet completed. Herein, we take advantage of the tacky partially polymerized surface of “green state” SLA 3D printed parts to immobilize extraction disks and miniature magnets, which after UV post-curing, become permanently attached to the 3D printed part resulting in a rotating-disk sorptive extraction device (RDSE). The developed “stick & cure” procedure is reagent-free and does not require any additional preparation time, specialized skills, or instrumentation. As proof of concept, 3D printed RDSE devices with immobilized chelating disks have been applied to the simultaneous extraction of 14 trace metals prior to ICP-OES determination, featuring LODs between 0.03 and 1.27 μg L−1, and an excellent device-to-device reproducibility (n = 5, RSD = 2.7–8.3%). The developed method was validated using certified wastewater and soil reference samples, and satisfactory spiking recoveries were obtained in the analysis of highly polluted solid waste treatment plant leachates (89–110%). In addition, exploiting the versatility of 3D printing, nine RDSE devices with different shapes were fabricated. Their performance was evaluated and compared for the fast extraction of the highly toxic Cr (VI) as its 1,5-diphenylcarbazide complex in reversed-phase mode, showing different extraction performance on depending on the shape of the 3D printed RDSE device.

Dynamic imaging provides novel insight into the shape and stability of soil aggregates

Soil structural traits provide links between soil structure and ecosystem functioning. The size and stability of soil aggregates are assumed to provide information on aggregate formation and turnover. A standard method to analyse these traits is to determine the mass distribution on sieves. The major drawback of this method is the small size resolution because of a small number of size classes. A promising, yet still unexplored, method for size distribution analysis in soil science, is dynamic image analysis, which foremost allows a much larger diameter resolution and the assessment of both size and shape distributions. The aim of our study was to validate the applicability of dynamic digital image analysis in combination with sonication to characterize the size and shape distribution and the stability of aggregates. We used two different heterogeneous reference materials and three different soil samples with different aggregate stabilities to test this method. The soil samples were chosen based on increasing clay, humus and calcium carbonate contents. The method yielded reproducible results for diameter and shape distributions for both reference materials and soil samples. The most important improvement compared to well‐established methods was the extremely large size resolution. This allows specification of the pattern of diameter‐dependent breakup curves by relating them to specific soil properties. The information on sphericity adds supplementary information on the aggregates released. We found much lower sphericity of 1‐mm aggregates mobilized from topsoil samples formed from the activity of living organisms than aggregates mobilized from subsoil samples formed mainly by physicochemical processes.Highlights Our aim was to validate dynamic digital image analysis to characterize soil aggregates. Dynamic image analysis allows high resolution and shape analysis compared to established methods. The method yielded reproducible results for diameter and shape distributions. We established high‐resolution disruption patterns of aggregates enabling new approaches in future research.

Replicability of aggregate disruption by sonication—an inter‐laboratory test using three different soils from Germany

AbstractSonication is widely used for disruption of suspended soil aggregates. Calorimetric calibration allows for determining sonication power and applied energy as a measure for aggregate disrupting forces. Yet other properties of sonication devices (e.g., oscillation frequency and amplitude, sonotrode diameter) as well as procedure details (soil‐to‐water ratio, size, shape, and volume of used containers) may influence the extent of aggregate disruption in addition to the applied energy. In this study, we tested potential bias in aggregate disruption when different devices or procedures are used in laboratory routines. In nine laboratories, three reference soil samples were sonicated at 30 J mL−1 and 400 J mL−1. Aggregate disruption was estimated based on particle size distribution before and after sonication. Size distribution was obtained by standardized submerged sieving for particle size classes 2000–200 and 200–63 µm, and by dynamic imaging for particles &lt; 63 µm. Despite differences in sonication devices and protocols used by the participants, only 16 in 216 tests of samples of the size fractions 2000–200 and 200–63 µm were identified as outliers. For the size fraction &lt; 63 µm, fewer outliers were detected (8 in 324 tests). Four out of nine laboratories produced more than two outliers. In these laboratories, sonication devices differed from the others regarding oscillation frequencies (24 or 30 kHz compared to 20 kHz), sonotrode diameters (10 and 14 mm compared to 13 mm), and sonication power (16 W compared to &gt; 45 W). Thus, these sonication device properties need to be listed when reporting on sonication‐based soil aggregate disruption. The overall small differences in the degree of disruption of soil aggregates between different laboratories demonstrate that sonication with the energies tested (30 and 400 J mL−1) provides replicable results despite the variations regarding procedures and equipment.

ANALYTICAL PERFORMANCE OF MICROWAVE-ASSISTED SOLVENT EXTRACTION (MASE) FOR THE ROUTINE DETERMINATION OF PAHs IN POLLUTED SOILS BY GAS CHROMATOGRAPHIC-MASS SPECTROMETRY (GC-MS)

The extraction of PAHs from polluted soil samples using Microwave Assited Solvent Extraction (MASE) with subsequent determination by Gas Chromatography-Mass Spectrometry (GC-MS) was investigated. Optimum conditions for the extraction are established and after the cleansing of extracts, those pollutants were quantified by GC-MS. Detection limits for the 16 US-EPA members of the family, analysis time, precision and linear range of the analysis have been also established. The proposed extraction methodology was compared with the most conventional Soxhlet extraction technique, and validated by applying the MASE to a reference soil sample. Good recoveries for the majority of PAHs (when calibrations were carried out by using internal standards), significant shortening time of analysis and reduction of volume of solvent used were observed. Thus, the MASE sample preparation methodology constitutes a very good alternative to extraction of PAHs from soil samples before the final determination by GC-MS.

Application of portable X-ray fluorescence spectrometry in environmental investigation of heavy metal-contaminated sites and comparison with laboratory analysis

In this study, portable X-ray fluorescence spectrometry (pXRF) was used to measure the heavy metal contents of As, Cu, Cr, Ni, Pb and Zn in the soils of heavy metal-contaminated sites. The precision, accuracy and system errors of pXRF were evaluated and compared with traditional laboratory methods to examine the suitability of in situ pXRF. The results show that the pXRF analysis achieved satisfactory accuracy and precision in measuring As, Cr, Cu, Ni, Pb, and Zn in soils, and meets the requirements of the relevant detection technology specifications. For the certified reference soil samples, the pXRF results of As, Cr, Cu, Ni, Pb, and Zn show good linear relationships and coefficients of determination with the values measured using the reference analysis methods; with the exception of Ni, all the measured values were within the 95% confidence level. In the soil samples, the coefficients of determination between Cu, Zn, Pb, and Ni concentrations measured laboratory pXRF and the values measured with laboratory analysis all reach 0.9, showing a good linear relationship; however, there were large deviations between methods for Cr and As. This study provides reference data and scientific support for rapid detection of heavy metals in soils using pXRF in site investigation, which can better guide the practical application of pXRF.

On the gamma spectrometry efficiency of reference materials and soil samples

The relative discrepancies between the gamma spectrometry efficiency of RGU, RGTh, RGK reference materials and some soil samples have been studied using a MCNP model of a real HPGe detector. It has been shown that, in a specified geometry, efficiencies differences depend on the sample elemental composition. The elemental compositions of RGU-1, RGTh-1 reference materials and a soil sample have been evaluated using X-Ray fluorescence (XRF) method and used in the MCNP simulation along with RGK-1 and six other soil samples with different elemental compositions to calculate their efficiencies in different gamma ray energies. To estimate the maximum relative efficiencies differences between soil samples and reference materials, five soil samples with higher attenuation properties were selected from a large data set of soils elemental compositions. The results show that the efficiency differences between soil samples and reference materials are almost ignorable for more than 100 KeV gamma energies. It strongly depends on the sample attenuation factor in the lower energies, so use of a self-attenuation correction is essential for radionuclide counting in low energies gamma rays. Results show about 8 percent discrepancy between RGU and two soil samples efficiencies in 63.2 KeV energy.

Field sampling of loose erodible material: A new system to consider the full particle-size spectrum

A new system is presented to sample and enable the characterization of loose erodible material (LEM) present on a soil surface, which may be susceptible for entrainment by wind. The system uses a modified MWAC (Modified Wilson and Cooke) sediment sampler connected to a corded hand-held vacuum cleaner. Performance and accuracy of the system was tested in the laboratory using five reference soil samples with different textures. Sampling was most effective for sandy soils, while effectiveness decreases were found for soils with high silt and clay contents in dry dispersion. This effectiveness decrease can be attributed to loose silt and clay-sized particles and particle aggregates adhering to and clogging a filter attached to the MWAC outlet. Overall, the system was found to be effective in collecting sediment for most soil textures and theoretical interpretation of the measured flow speeds suggests that LEM can be sampled for a wide range of particle sizes, including dust particles. Particle-size analysis revealed that the new system is able to accurately capture the particle-size distribution (PSD) of a given sample. Only small discrepancies (maximum cumulative difference <10% at 63 μm) were found between the PSDs before and after vacuuming for all test soils. Despite limitations of the system, it is an advance toward sampling the full particle-size spectrum of loose sediment available for entrainment with the overall goal to better understand the mechanisms of dust emission and their variability.