Fluorine contamination, mobility, and risks in soils at a phosphate-gypsum waste landfill: a new analytical method and comparison with previous methods.

This study used a new X-ray fluorescence (XRF)-based analytical method with better precision and sensitivity to evaluate the fluorine concentrations in soil. It was hypothesized that the XRF method with a pellet-synthesizing procedure may effectively analyze the fluorine concentrations in soil with ease and reliability. The total fluorine concentrations determined using XRF were compared with those determined using three different types of analytical protocols-incineration/distillation, alkaline fusion, and aqua regia extraction procedures. Among the three procedures, the incineration/distillation procedure did not show reliable precision and reproducibility. In contrast, the total fluorine concentrations determined using the XRF analysis were linearly correlated with those determined using the alkaline fusion and aqua regia extraction procedures. Based on the results of the Korean waste leaching procedure and toxicity characteristics leaching procedure, the leachability of fluorine from soil and waste was not directly related to total fluorine concentrations in soil. Risk assessment also revealed that the fluorine-rich soils did not show non-carcinogenic toxic effects, despite exceeding the regulation level (800 mg/kg) in South Korea for total fluorine concentrations in soil. Our results suggest that XRF analysis in combination with the newly developed pretreatment method may be a promising alternative procedure for easily and rapidly determining the total fluorine concentration in soil. However, further efforts are needed to evaluate fluorine leachability and its associated risks in fluorine-contaminated soils.

Unexpected Dioxin Formation During Digestion of Soil with Oxidizing Acids.

Dioxins, such as polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs), are among the most toxic unintentionally produced persistent organic pollutants, and their emission is of great concern. Herein, we discovered abundant dioxin formation in soil and various organic carbon-containing matrices after digestion with aqua regia. Σ17PCDD/Fs concentrations were in the range of 66.6-142,834 pg/g dw (5.6-17,021 pg WHO2005-TEQ/g dw) in 19 soil samples after digestion with aqua regia for 6 h. Σ17PCDD/Fs concentration was significantly and positively correlated with soil organic carbon content (R2 = 0.89; p < 0.01). Compared with cellulose and lignin, humic acid served as an important organic matter component that was converted to PCDD/Fs during soil digestion. Strong oxidation and production of reactive chlorine by aqua regia may be the key factors in the formation of PCDD/Fs. The yearly emission of PCDD/Fs due to digestion with strong acids by the inspection and testing industry was estimated to be 83.8 g TEQ in China in 2021 based on the highest level, which was ∼0.9% of the total dioxin inventory in China. Great attention should be paid to unexpected dioxin formation during digestion processes considering the potential risk of release from laboratories and enterprises.

Targeting of platinum capture under 1+1 aqua regia using robust and recyclable polymeric polyamine resin: Adsorption performance and mechanism.

The targeted capture of platinum from complex and harsh acidic digests such as those platinum-containing secondary resources is essential from the perspectives of green development. Here, a polyamine chelating resin (CMPs-PEI) with excellent selectivity and acid resistance was prepared by a nucleophilic substitution reaction using chloromethylated polystyrene as the parent and polyethyleneimine as the modifier. The experimental results revealed that the adsorbent showed excellent adsorption effect on platinum under different acidities, and its maximum adsorption capacity was up to 337 mg/g at pH 2. More impressively, a rather high capacity of 162.41 mg/g was achieved in 1 + 1 aqua regia (pH -0.7), which was much higher than other adsorbent materials under the same conditions. In addition, the recovery of platinum by CMPs-PEI in practical platinum-containing iron concentrate abatement solution was 100 %. Mechanistic studies showed that the protonated amine groups on CMPs-PEI bound PtCl62- and partially reduced PtCl42- by electrostatic attraction. Meanwhile, the excellent regeneration performance of CMPs-PEI indicated that it showed great potential for green and economic recovery of precious metal ions.

Revealing XRF data quality level, comparability with ICP-ES/ICP-MS soil PTE contents and similarities in PTE induced health risk.

Portable X-ray fluorescence spectroscopy (XRF) was recognized as an efficient and promising tools to study the contents of chemical elements in various media including soils under the impact of anthropogenic activities. However, the quality of data and the equality of chemical elements with other common analytical methods such as aqua-regia extraction vary depending on site, sample conditions, and analysis time. In this study, we examine the adequacy of XRF and ICP-ES/ICP-MS aqua-regia extractable (AR) results obtained for lab-type pretreated samples (N = 15) for Ti, Fe, Mn, Co, V, Pb, Zn, Cu, Cr, Mo, Sr, and As contents in soils under the impact of copper smelter and assess the equality of PTE contents induced health risk. The obtained results suggested that XRF reached definitive data quality level for As, Zn, and Mn and screening (quantitative) data quality level established for Cu, Pb, Fe, Mo, Cr, V, and Ti. Moreover, in some cases (i.e., for Ti) XRF overperformed AR indicating the high efficiency of XRF application when sparingly soluble mineral matrices are presented. At the same time, PTE induced health risk assessment at the established data quality level showed that equality of non-carcinogenic children health risk was observed for As, Zn, Cu, Pb, Mn, and V. The latter indicating the applicability of XRF to generate reliable base for risky sites identification and characterization.

Sulfur analyses and mineralogical data in the preliminary mine waste characterization.

The objective of this study was to investigate the use of the acid production potential (AP) calculation factor and seven different S analysis methods in the preliminary mine waste characterization by analyzing and comparing 48 Finnish mine waste samples. Special attention was paid on mineralogical aspects and data produced in the exploration phase of a mining project.According to our results, the abundance of sulfide species other than pyrite in Finnish mine waste suggests that the factor to calculate the AP should be considered based on mineralogy and would often be below 31.25. Therefore, the mineralogy-based determination of S should be preferred. However, the determination of S based on scanning electron microscope (SEM) mineralogy includes some uncertainties. Underestimation of S content may appear if not all S-bearing mineral particles have been detected, or if the amount of S is low in general. This uncertainty appears to be especially related to the samples containing elevated (> 9 wt%) amounts of serpentine, diopside, augite, and/or hornblende. Risk of overestimating AP is related to samples containing high amounts (> 4.13 wt%) of S-bearing minerals. These uncertainties can be reduced by inspecting that the SEM mineralogy-based S concentrations are in line with the energy dispersive X-ray spectrometer data. The aqua regia extractable S concentrations, which are often available in the exploration phase, appeared to be usable in the preliminary waste rock AP assessment and often comparable with the analytical total S values in the Finnish waste rock samples, especially when the samples did not contain any sulfate minerals. In contrast, the analytical sulfide S and the X-ray fluorescence methods may lead to an underestimation of AP.

Crystal Structure Dependent Dissolution of Non-Cubic Au Crystallites in Aqua Regia.

Properties of metal crystallites are governed by their morphologies and inherent crystal structures. In this work, bipyramidal Au microcrystallites hosting non-cubic lattices, body-centered orthorhombic and tetragonal (together termed as bc(o,t)), are investigated for their stability in aqua regia. Specifically, microcrystallites comprising 92 % of bc(o,t) have been subjected to aqua regia of different concentrations and the changes in morphology and lattice phases have been monitored using scanning electron microscopy and X-ray diffraction techniques. The dissolution process was found to be crystal structure dependent and begin at the bipyramidal tips enriched with fcc lattice while retaining the bc(o,t) rich body. Interestingly, with increasing the reaction times, the remaining core was found to be highly reluctant to dissolution and instead, transformed to tetragonal lattices which with increasing treatment, exhibited lattice parameters closer to that of fcc. The study reveals the presence of a bc(o,t)-fcc core-shell structure with the tips enriched with fcc.

Environmental impact of high-value gold scrap recycling.

PURPOSE: The gold routes satisfying the global gold supply are mining (74%), recycling of high-value gold (23%), and electronic scraps (3%). Besides its applications in the investment, jewelry, and industrial sector, gold also has a bad image. The gold production in industrial as well as artisanal and small-scale mines creates negative impacts such as resource depletion, extensive chemical use, toxic emissions, high energy consumption, and social concerns that are of great importance. On the other hand, almost all gold is recycled and has historically always been. In common life cycle assessment (LCA) databases, there is no data on recycling of high-value gold available. This article attempts to answer the question what the ecological benefits of this recycling are. METHOD: In this study, we were able to collect process data on the most commonly used high-value gold scrap recycling process, the aqua regia method, from several state-of-the-art German refineries. With this data, life cycle inventories were created and a life cycle model was produced to finally generate life cycle impacts of high-value gold scrap recycling. RESULTS: This study contains the corresponding inventories and thus enables other interested parties to use these processes for their own LCA studies. The results show that high-value gold scrap recycling has a considerably lower environmental impact than electronic gold scrap recycling and mining. For example, high-value gold scrap recycling in Germany results in a cumulative energy demand (CED) of 820 MJ and a global warming potential (GWP) of 53 kg-CO2-Eq. per kg gold. In comparison, common datasets indicate CED and GWP levels of nearly 8 GJ and 1 t-CO2-Eq. per kg gold, respectively, for electronic scrap recycling and levels of 240 GJ and 16 t-CO2-Eq. per kg gold, respectively, for mining. CONCLUSION: The results show that buying gold from precious metal recycling facilities with high technological standards and a reliable origin of the recycling material is about 300 times better than primary production.

Assessment of the trace element distribution in soils in the parks of the city of Zagreb (Croatia).

This paper presents the results of the preliminary testing of the selected trace elements in the soils of several parks in the city of Zagreb, Republic of Croatia. In each park, the samples were taken from several points-at various distances from the roads. The samples were taken at two different depths: 0-5 and 30-45 cm. Composite samples were done for each sampling point. Microwave-assisted wet digestion of the soil samples was performed and the determination by ICP-AES technique was done. Results obtained for Al, As, Ba, Mn, Ti, V, and K are in a good agreement with the results published in the scientific literature so far. The mass fraction values of Cd, Cr, Cu, Ni, Pb, and Zn are somewhat higher than the maximum values given in the Croatian Directive on agricultural land protection against pollution. Be, Mo, Sb, Se, and Tl in the samples were present in the concentrations that are lower than their method detection limit values.

Nobler than the Noblest: Noncubic Gold Microcrystallites.

Conventional gold comprising the cubic lattice is universally known for its stability. However, well known to chemists and metallurgists, this nobility is challenged by reagents such as aqua regia, which dissolve gold to form a salt solution. Among metals, mercury blends with gold to form amalgam, otherwise transition metals such as copper tend to interact with gold surfaces in electrochemical media. Herein, we report a combined experimental and theoretical investigation of the stability of Au microcrystallites bearing unconventional crystal lattices that exhibit enhanced stability towards Hg and aqua regia and practically no interaction with Cu during electroless plating. The unconventional gold is undoubtedly nobler.

Relationship between heavy metals and minerals extracted from soil clay by standard and novel acid extraction procedures.

Strong acid digestions are commonly used to determine heavy metal (HM) contents in soils. In order to understand more fully the acid digestion processes, a logical step is to determine the extent of dissolution of mineral phases. The aims of this study were to compare the efficiency of extraction of HM by different acid digestions and to monitor the associated dissolution of the clay fraction. The context of the study was to develop a milder chemical extraction method (microwave-assisted 1 mol L-1 HNO3 closed system (NACS)), which recovers more reactive HM and with little dissolution of minerals. The different acid digestion methods dissolved different amounts of minerals from the clay fraction. Both aqua regia (AR) and EPA 3051 dissolved all of the Fe and Al oxides, and the dissolution of kaolin was limited to thinner particles (c dimension), smaller particles in a and b dimensions and grains with lower crystallinity. The lower recovery of HM for AR compared with EPA 3051 was related to the large amount of short-range order phases formed during the AR extraction as these phases have the capacity to re-adsorb HM. The new method (NACS) has the potential to replace other methods of determining bioavailable forms of HM, such as AR and EPA 3051. The contents of Pb, As, Co, Zn, and Cu determined by EPA 3051 and EPA 3052 were quite close.

Low carrier density epitaxial graphene devices on SiC.

The transport characteristics of graphene devices with low n- or p-type carrier density (∼10(10) -10(11) cm(-2) ), fabricated using a new process that results in minimal organic surface residues, are reported. The p-type molecular doping responsible for the low carrier densities is initiated by aqua regia. The resulting devices exhibit highly developed ν = 2 quantized Hall resistance plateaus at magnetic field strengths of less than 4 T.

A simple and accurate method for the determination of Rh, Pd, and Pt in e-waste and spent automotive catalysts using HR-CS FAAS for assessing the value of secondary raw materials.

This work presents a simple and accurate method for the fast sequential determination of Rh, Pd, and Pt in spent automotive catalysts and e-wastes using high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). Extensive research was carried out in model systems on the impact of potential interfering substances on analyte's signals measured in two types of flame (air-C2H2 and N2O-C2H2). Mutual analyte interactions were also taken into account. Different background corrections offered by the HR-CS AAS spectrometer were tested to obtain interference-free analyte signals and the best detectability. Using an air-C2H2 flame and 1 % La solution as a spectrochemical buffer provided good sensitivity and accurate determinations of Rh, Pd, and Pt using a simple calibration graph. Microwave-assisted leaching of PGE from waste samples with aqua regia at 240 °C for 60 min efficiently leached all target metals, which significantly simplified and shortened the sample preparation step. The detectability of the method (detection limit of 0.4, 0.6, and 5 mg kg-1 for Rh, Pd, and Pt, respectively) and precision (< 7 %) were satisfactory. The accuracy of the method was confirmed by analysis of certified reference materials (spent automotive catalyst (ERM-EB504), electronic scrap (BAM-M505a)), and calculated zeta score values. The recoveries for Rh, Pd, and Pt in ERM-EB504 were 93, 101, and 96 %, respectively, and for Pd in BAM-M505a, 97 %. The developed method can be used to assess the value of secondary raw materials, such as various types of spent catalysts and e-waste containing Rh, Pd, and Pt.

Evaluation of asphalt film thickness and heavy metal leaching of oxidizing slag used as an aggregate material in dense-graded asphalt concrete.

Electric-arc-furnace (EAF) steelmaking uses scrap iron and steel as raw materials. Scrap iron and steel originate from complex sources and may contain heavy metal components which can leach into the environment over time due to wear-and-tear. A by-product of the EAF steelmaking process is oxidizing slag, and approximately 1.2 million metric tons is produced every year in Taiwan alone. This study investigated substitution of natural aggregates with oxidizing slag in dense-graded asphalt concrete. We evaluated the water resistance and asphalt film thickness of the oxidizing slag substituted asphalt concrete and further explored the performance of oxidizing slag as paving material. We determined the dissolved and total amounts of heavy metals in the oxidizing slag, comparing these results with current regulatory controls to assess the environmental compatibility of the oxidizing slag. We found that due to the complicated sources of oxidizing slag, the basic properties should be analyzed on a batch-to-batch basis. Furthermore, we recommend trial mixing before upscaling the production of oxidizing slag substituted dense-graded asphalt concrete to confirm the mixing time required to achieve uniformity. The results also show that in comparison to natural aggregates used in asphalt concrete, oxidizing slag exhibits superior performance in terms of increased asphalt film thickness and improved water resistance. Furthermore, oxidizing slag as an aggregate material was associated with decreased heavy metal leaching and reduced environmental pollution. The results of the toxicity characteristic leaching procedure (TCLP) met regulatory requirements. However, the microwave-assisted aqua-regia digestion procedure showed heavy metal concentrations exceeding the monitoring standards for food crops. Considering environmental compatibility, it is recommended that controlling the total amount of heavy metals in oxidizing slag should be included in regulatory requirements. Furthermore, we should prohibit the use of materials such as oxidizing slag and other steel furnace slag in the roadways adjacent to edible crop farmlands.

Cleaning deteriorated elements of ammunition: Development of a procedure applied to cartridge cases from the Second World War.

Deteriorated elements of ammunition can be found while investigating different types of events. Exposure to adverse environmental conditions may lead to metal alteration (corrosion) or organic material deposition (contaminations) on the exposed elements of ammunition. From a forensic perspective, both types of deterioration pose challenges when observing marks left by the firearms used to discharge the corresponding ammunition (e.g. firing pin, extractor). The longer the time of exposure to the adverse environmental conditions, the more challenging the observation of such marks. A literature review highlighted three previously published restorative methods used to clean deteriorated elements of ammunition. The aim of this research is to develop a cleaning procedure applicable to cartridge cases exposed to adverse environmental conditions, while avoiding the degradation of marks left by the firearms used to discharge the corresponding ammunition. A first batch of 21 brass cartridge cases dating back to the Second World War (WWII) was used to develop a cleaning sequence involving the three methods. The efficiency of each restorative method was qualitatively assessed using optical macroscopy and the Evofinder® ballistic identification system. The developed sequence relies on successive applications of Tickopur® TR 7 (a diluted soft metal cleaner), sulfuric acid and finally Aqua Regia (HCl 37% and HNO3 75%), all of them involving ultrasonic baths. The resulting cleaning sequence was subsequently applied to three batches of Second World War cartridge cases discovered in France and Russia. This sequential procedure allows the effective cleaning of WWII brass cartridge cases while highlighting different marks left by firing pins, extractors, ejectors, and breech faces. Applying a forensic analysis and comparison process to the marks highlighted on these elements of ammunition can support the verification of historical facts when reconstructing events which took place more than seventy years ago.

Selective recovery of gold from dilute aqua regia leachate of waste printed circuit board by thiol-modified garlic peel.

Garlic peel (GP) was chemically modified by using thiourea under hydrothermal treatment, which could selectively adsorb gold ions from the 1/10 dilute aqua regia media directly without needing the dangerous evaporation operation. The synthetic chloroauric solution and practical leach liquor of the waste PCB (printed circuit board) powder in dilute aqua regia were employed to assess the adsorption performance on the thiol-GP and the commercial quaternary ammonia anion resin of D201, respectively. It was experimentally confirmed that the adsorption efficiency of gold onto the thiol-GP and D201 resin both reached 100%, and the maximum adsorption capacity of thiol-GP gel was evaluated as 42.59 mg Au/g that was much larger than that of D201 resin (3.33 mg Au/g). The thiol-GP gel adsorption efficiency of other coexisting base metal ions like Cu2+, Ni2+, Al3+, and Fe3+ from dilute aqua regia leach liquor of the waste PCB powder was near zero, and only gold could be enriched by selective adsorption onto the thiol-GP gel. At least 3 cycles of adsorption/elution could be obtained without decreasing the adsorption efficiency drastically. The adsorbed gold on the thiol-GP was able to be eluted effectively by using the mixture solution of 0.1 M thiourea and 0.1 M hydrochloric acid, and finally the solid gold could be recovered by sodium borohydride through a reduction process. This study demonstrated a green, environmentally friendly, low-cost, and efficient method for selective recovery of gold from the dilute leach liquor (aqua regia) of waste circuit boards.

Sediment quality of the Ridracoli fresh water reservoir in Italy: Insights from aqua regia digestion and sequential extractions.

The inter-element relationships and the forms in which metals exist strongly influence their mobility and, in turn, have a signature on the environment and human health. Located in the northern Apennines within the Emilia-Romagna region, the Ridracoli artificial lake is one of Italy's most important reservoirs that provides drinking water for about one million people. This work characterized the reservoir sediments by ICP-MS after aqua regia digestion (ARD), comparing the limits by law to assess environmental compliance and XRF data from the same sample-set taken as total concentrations. The Degree of Extraction (DE) from pseudo-total concentrations of ARD analysis allows assessing elements mobility and the associated environmental risk. Principal Component Analysis (PCA) on the obtained data helped to investigate inter-element relationships better; for example, we observed carbonate-sourced sediments, many trace elements (e.g., Ni, Zn) linked to FeMn oxyhydroxides, the importance of the grain size in elements distribution, and the central role of the organic matter in element partitioning. In addition, a Sequential Extraction Procedure (SEP) was applied to the sediment samples to understand the partitioning of many analytes, including Potentially Harmful Elements (PHE) such as Fe, Mn, Cu, Cr, Ni, Pb, and Zn. The results indicated that the most easily mobilized forms were predominant in the area near the dam, in correspondence to sediments affected by the formation of a seasonal anoxic layer.

Heavy metal contents, mobility and origin in agricultural topsoils of the Galápagos Islands.

While the Galápagos Islands have been renowned for their unique flora and fauna since the time of Charles Darwin, the soils of the isolated island chain have been mostly overlooked and little information on their heavy metal contents is available. The aim of this study was therefore to examine the total heavy metal (Cd, Co, Cr, Cu, Ni, Pb, U, Zn) contents of soils from the agricultural areas on islands Isabela, Santa Cruz and San Cristóbal, and identify trends with duration of exposure to weathering processes. Additionally, the mobility of these elements was assessed using ammonium nitrate extraction. In general, levels of Cd, Co, Cr, Cu, Ni and Zn were high compared to other world locations, while Pb levels were low and U levels were similar. Ni, Co, Cr, and to a lesser extent Pb and U tended to accumulate with increasing weathering duration. Soil concentrations of Cd, Zn, Cu, and possibly Pb and U, may have been influenced by use of agrochemicals, particularly on Santa Cruz Island. Mobility of Cd displayed an increasing trend with soil age, while Ni mobility decreased. Many soils had total contents of Cd, Co, Cr, Cu, Ni and Zn above threshold values indicating possible ecological or health risks. Systematic examination of trace element contents in soils from pristine national park areas would further assist in the delineation of background levels and the development of soil quality standards to ensure crop quality, animal and human health on this unique island chain.

Aqua regia digestion cannot completely extract Hg from biochar: A synchrotron-based study.

Mercury (Hg) is commonly extracted from solid phase samples using aqua regia for total Hg (tHg) analysis. However, uncertainties exist regarding the complete extraction of Hg by aqua regia, especially from carbonaceous materials. To investigate whether aqua regia can completely extract Hg from biochars, batch-style experiments were carried out to evaluate extraction efficiency of aqua regia with respect to Hg-loaded biochar and to characterize the residual Hg speciation and spatial distribution. Different types of biochars (raw, FeCl3-modified, and FeSO4-modified, prepared at different temperatures) were reacted with Hg-spiked solution before the digestion experiments. Adsorption analyses indicate the biochars were successfully loaded with Hg and that the Hg content was higher in biochars pyrolyzed at higher temperature (900 versus 300 or 600 °C). The results of digestion experiments indicate Hg could not be completely extracted from the biochars tested, with a greater percentage of residual Hg in biochars pyrolyzed at 600 (60 ± 15%) and 900 (75 ± 22%) than 300 °C (7 ± 2%). Furthermore, the fraction of residual Hg in FeSO4-modified biochars after aqua regia digestion was significantly lower than in FeCl3-modified and unmodified biochars. Confocal micro-X-ray fluorescence imaging (CMXRFI) showed residual Hg in biochars is concentrated on surfaces prior to digestion, but more homogeneously distributed after digestion, which indicates Hg on biochar surface is more easily digested. Hg extended X-ray absorption fine structure (EXAFS) spectra modelling showed residual Hg in biochars mainly exists as Hg(II)-Cl. These results indicate extra caution should be paid for tHg determinations using aqua regia digestion method in soil (especially in forest), sediment, and peat samples containing black carbon, activated carbon, or biochar.

Highly Active AuCu-Based Catalysts for Acetylene Hydrochlorination Prepared Using Organic Aqua Regia.

Development of a sustainable process for designing and synthesising an active and stable catalyst for hydrochlorination of acetylene is challenging, yet crucial, for industrial vinyl chloride monomer (VCM) production. Herein, direct synthesis of bimetallic AuCu catalysts using organic aqua regia (OAR) preparation methods was investigated. In comparison with conventional aqua regia (AR), bimetallic AuCu catalysts synthesised from OAR exhibit enhanced activity and stability. After careful characterisation of the catalyst samples using X-ray diffraction patterns (XRD), Scanning transmission electron microscopy (STEM), X-ray photoelectron spectroscopy (XPS), and Temperature-programmed desorption (TPD), this observation was justified for the following reasons: 1) the existence of sulphur and nitrogen atoms stabilised the cationic Au active sites, and 2) OAR helped to sustain the function of the Cu promotor by stabilising it. Advanced understanding on the importance of promoter stability has unveiled new perspectives for this research area.

Quick Analysis of Organic Amendments via Portable X-ray Fluorescence Spectrometry.

The determination of heavy metals in soils and organic amendments, such as compost, manure, biofertilizer, and sludge, generally involves the digestion of samples with aqua regia, and the determination of those in the solution using various techniques. Portable X-ray fluorescence (PXRF) has many advantages in relation to traditional analytical techniques. However, PXRF determines the total elemental content and, until now, its use for the analysis of organic amendments has been limited. The objective of this work is the calibration of a PXRF instrument to determine the aqua regia-soluble elemental contents directly in solid samples of organic amendments. Our proposal will avoid the digestion step and the use of other laboratory techniques. Using a training set of samples, calibration functions were obtained that allow the determination of the aqua regia-soluble contents from the PXRF readings of total contents. The calibration functions (obtained by multiple linear regression) allowed the quantitative determination of the aqua regia-soluble contents of Fe, K, P, S, Zn, Cu, Pb, Sr, Cr, and Mn, as well as the organic matter content and a semi-quantitative assessment of Al, Ca, V, Ba, Ni, and As contents. The readings of Si, Fe, Al, Ca, K, or S were used as correction factors, indicating that the calibrations functions found are truly based on the chemical composition of the sample matrix. This study will allow a fast, cheap, and reliable field analysis of organic amendments and of other biomass-based materials.