Recovery of rare earth elements from waste phosphors via alkali fusion roasting and controlled potential reduction leaching.

Waste phosphors, which contain the quantity of rare earth and toxic metals, need to be recycled for both environmental protection and the sustainable development of rare earth resources. Due to the magnesium-aluminum spinel structure, it is difficult to extract cerium and terbium from waste phosphors. In this study, a facile process for recovering rare earth elements from waste phosphors was developed. First, the waste phosphors were alkali roasted to destroy the aluminum-magnesium spinel structure in the blue and green powders. NaOH was found to be a more suitable additive than Na2CO3, NaHCO3, and K2CO3 for alkali roasting. Then, the roasted slag was washed with water to remove the aluminum and controlled potential reduction leaching was conducted. FeCl2 was used as the reductant (dosage of 0.04) in the 3 mol·L-1 HCl solution at a leaching temperature of 50 °C for 60 min. The leaching efficiencies of Y, Eu, Ce, and Tb were up to 99.1 %, 99.4 %, 98.6 %, and 98.8 %, respectively. The reduction leaching process obeys the shrinking core model and depends on the diffusion. This process can effectively improve the leaching efficiency of rare earth elements from waste phosphors and provides theoretical and technical support for the recycling of waste phosphors.

Selective recovery of rare earth elements and value-added chemicals from the Dicranopteris linearis bio-ore produced by agromining using green fractionation.

The increasing demand for Rare Earth Elements (REEs) and the depletion of mineral resources motivate sustainable strategies for REE recovery from alternative unconventional sources, such as REE hyperaccumulator. The greatest impediment to REE agromining is the difficulty in the separation of REEs and other elements from the harvested biomass (bio-ore). Here, we develop a sulfuric acid assisted ethanol fractionation method for processing D. linearis bio-ore to produce the pure REE compounds and value-added chemicals. The results show that 94.5% of REEs and 87.4% of Ca remained in the solid phase, and most of the impurities (Al, Fe, Mg, and Mn) transferred to the liquid phase. Density functional theory calculations show that the water-cation bonds of REEs and Ca cations were broken more easily than the bonds of the cations of key impurities, causing lower solubility of REEs and Ca compounds. Subsequent separation and purification led to a REE-oxide (REO) product with a purity of 97.1% and a final recovery of 88.9%. In addition, lignin and phenols were obtained during organosolv fractionation coupled with a fast pyrolysis process. This new approach opens up the possibility for simultaneous selective recovery of REEs and to produce value-added chemicals from REE bio-ore refining.

A review of the application of cerium and lanthanum in phosphorus removal during wastewater treatment: Characteristics, mechanism, and recovery.

Owing to their strong bond with anions, rare earth elements (REEs) are prime contenders in wastewater treatment to meet the stringent phosphorus (P) effluent quality requirements. REEs outcompete traditional metals to abate phosphorus. The application of lanthanides in wastewater treatment is mainly through adsorption, where REEs are incorporated into a carrier matrix to improve the adsorption capacity. As coagulants, information on the performance of lanthanides is lacking. In this review, the performance of major water coagulants (iron and aluminum) is discussed and compared to two lanthanides: cerium and lanthanum. The use of lanthanides as adsorbents and as coagulants is elucidated during P treatment. The recovery of P and REEs is also discussed. Where details were lacking in the literature, experiments were conducted to fill these research gaps. Using REEs as adsorbents limits their P precipitation potential; as coagulants, REE capacity is 520.79 mg P/g La3+ and 469.96 mg P/g Ce3+. In addition, as coagulants, they are not affected by pH (3.0 < pH < 10.0); however, carbonates and sulfate are the major species that can reduce the performance of REEs during P treatment. REE-P precipitation is orchestrated through the formation of an REE-PO4 bond. Unfortunately, this strong bond between lanthanides and phosphate makes phosphate recovery almost impractical. If the goal is to recover REEs and reuse P in other applications like fertilizers, REEs are not the best candidates. We recommend additional research dedicated to understanding lanthanide coagulants in typical wastewater treatment facilities and their release from phosphate precipitates under different environmental conditions.

Rationally designed upconversion nanoparticles for NIR light-controlled lysosomal escape and nucleus-based photodynamic therapy.

Cell nucleus-based photodynamic therapy is a highly effective method for cancer therapy, but it is still challenging to design nucleus-targeting photosensitizers. Here, we propose the "one treatment, multiple irradiations" strategy to achieve nucleus-based photodynamic therapy using the photosensitizer rose bengal (RB)-loaded and mesoporous silica-coated upconversion nanoparticles with the surface modification of amine group (UCNP/RB@mSiO2-NH2 NPs). After implementation into cancer cells, the rationally designed UCNP/RB@mSiO2-NH2 NPs could be specifically accumulated in the acidic lysosomes due to their amino group-decorated surface. Upon a short-term (3 min) irradiation of 980 nm near-infrared light, the reactive oxygen species produced by RB through the Förster resonance energy transfer between the upconversion nanoparticles and RB molecules could effectively destroy lysosomes, followed by the release of the UCNP/RB@mSiO2-NH2 NPs from the lysosomes. Subsequently, these released UCNP/RB@mSiO2-NH2 NPs could be transferred into the cell nucleus, where a second 980 nm light irradiation was conducted to achieve the nucleus-based photodynamic therapy. The rationally designed UCNP/RB@mSiO2-NH2 NPs showed excellent anticancer performance in both two-dimensional and three-dimensional cell models using the "one treatment, multiple irradiations" strategy.

Apatite matrix substituted with biologically essential rare earth elements as an artificial hard tissue substitute: Systematic physicochemical and biological evaluation.

Hydroxyapatite (HAP) forms the main inorganic component of natural bone and hence has been widely use in implant applications. Ionic substitutions in apatite also gains enormous interest during the recent years due to the crucial role played by these elements in the biological process. In this context, the least investigated elements namely lanthanum (La3+ ) and praseodymium (Pr3+ ) have been selected as a potential substitutions in apatite. The results from the analytical techniques confirm the phase purity of the HAP and its ability holds the substitutions at its lattice. Morphological analysis unveils the presence of agglomerated spheroids notwithstanding the ion concentration of substituents. EDX spectra affirm the presence of La and Pr alongside the determined Ca/P atomic ratio of 1.67. La3+ and Pr3+ presence envisaged the good antibacterial efficiency against the tested microbes and further demonstrated the biocompatibility nature from the cytotoxicity analysis.

Analysis of the absorption and accumulation characteristics of rare earth elements in Chinese tea.

BACKGROUND: Rare earth elements (REEs) played an important role in enhancing the yield and quality of tea, and have been widely used in tea cultivation. In the present study, 3011 tea samples of four tea types, namely black tea, green tea, oolong tea and dark tea, were collected from the mainly tea producing areas in different provinces of China to analyze the contents of 16 REEs by inductively coupled plasma mass spectrometry. RESULTS: The results obtained showed that the higher average content of REEs was 2.960 mg kg-1 in black tea from Henan province, 2.500 mg·kg-1 in green tea from Shanxi province, 3.870 mg·kg-1 in oolong tea from Guizhou province and 2.955 mg·kg-1 in dark tea from Hunan province. The sum percentage of five elements (Sc, Y, La, Ce, and Nd) to total REEs was 84.39% in black tea, 85.07% in green tea, 83.67% in oolong tea and 84.42% in dark tea. In addition, the content of Ce in tea was greatest, regardless of the province of China. The content trend of the five REEs was Ce > La > Sc > Nd > Y in black and green tea, respectively. However, the content trend was Ce > Y > Sc > Nd > La in oolong tea and Ce > Y > La > Nd > Sc in dark tea. CONCLUSION: The tea leaves mainly accumulated light REEs rather than heavy REEs. These results provided an important theoretical basis for investigation of the accumulation characteristics of REEs in Chinese tea. © 2020 Society of Chemical Industry.

Synthesis of Catechin-Rare Earth Complex with Efficient and Broad-Spectrum Anti-Biofilm Activity.

Biofilm is the crucial reason of clinical infections. Herein, green tea based polyphenol (catechin) and rare earth (RE) metal ions were employed for the preparation of catechin-RE complexes with significant anti-biofilm properties. The complexes were characterized by FT-IR, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS), which suggested that catechin coordinated with RE3+ through its ortho phenolic hydroxy groups. The prepared catechin-RE showed significant effects in anti-biofilm growth against P. aeruginosa (Gram-negative bacteria), S. sciuri (Gram-positive bacteria), and A. niger (fungi), which significantly exceeded the utilization of catechin or RE3+ . Morphological observations indicated that catechin supplied cell affinity to transfer RE3+ and helped to damage cell membrane, which act as a carrier to exert cytotoxicity of RE3+ to realize anti-biofilm. Differential gene expression analysis described gene expression changes induced by catechin-RE, including 56, 272 and 2160 downregulated genes for P. aeruginosa, S. sciuri and A. niger, respectively, which suggested critical changes in cellular metabolism, growth and other processes. These results illustrate the outstanding superiority of catechin-RE complexes in anti-infection aspect, i. e., the green tea based rare earth complexes are promising candidates for anti-biofilm applications to address serious challenges in the prevention of multiple infections.

Control synthesis, subtle surface modification of rare-earth-doped upconversion nanoparticles and their applications in cancer diagnosis and treatment.

Rare earth doped upconversion nanoparticles (UCNPs) are a new class of luminescent materials that can absorb long-wavelength near-infrared photons and emit short-wavelength UV-visible photons. UCNPs have little damage to biological tissues, have deep tissue penetration ability, have no background fluorescence noise interference, have high imaging sensitivity, and have no photobleaching effect. In the field of biomedicine, especially in the field of diagnosis and treatment of cancer, a wide range of research interests has arisen. In this paper, we briefly introduce the luminescent principle of rare-earth doped UCNPs, discuss several widely used control synthesis and modification methods, and focus on the research progress of UCNPs in detection of cancer cells, photodynamic therapy (PDT) and photothermal therapy (PTT) field. We also summarize the application of UCNPs as a diagnostic and therapeutic integrated nanoplatform in the diagnosis and treatment of cancer. At last, we explore the application challenge and prospect of UCNPs in oncology field.

Simple Preparation of LaPO4:Ce, Tb Phosphors by an Ionic-Liquid-Driven Supported Liquid Membrane System.

In this work, LaPO4:Ce, Tb phosphors were prepared by firing a LaPO4:Ce, Tb precipitate using an ionic-liquid-driven supported liquid membrane system. The entire system consisted of three parts: a mixed rare earth ion supply phase, a phosphate supply phase, and an ionic-liquid-driven supporting liquid membrane phase. This method showed the advantages of a high flux, high efficiency, and more controllable reaction process. The release rate of PO43- from the liquid film under different types of ionic liquid, the ratio of the rare earth ions in the precursor mixture, and the structure, morphology, and photoluminescence properties of LaPO4:Ce, Tb were investigated by inductively coupled plasma-atomic emission spectroscopy, X-ray diffraction, Raman spectra, scanning electron microscopy, and photoluminescence emission spectra methods. The results showed that a pure phase of lanthanum orthophosphate with a monoclinic structure can be formed. Due to differences in the anions in the rare earth supply phase, the prepared phosphors showed micro-spherical (when using rare earth sulfate as the raw material) and nanoscale stone-shape (when using rare earth nitrate as the raw material) morphologies. Moreover, the phosphors prepared by this method had good luminescent properties, reaching a maximum emission intensity under 277 nm excitation with a predominant green emission at 543 nm which corresponded to the 5D4-7F5 transition of Tb3+.

THERMOLUMINESCENCE SPECTRA AND DOSE RESPONSES OF SrSO4 PHOSPHORS DOPED WITH RARE EARTHS (Eu, Dy, Tm) AND PHOSPHORUS.

The thermoluminescence (TL) spectra and dose responses of strontium sulphate doped with rare earth ions show that the SrSO4:Eu2+ phosphor might reasonably be assumed a isoelectronic trap sample which has unique TL characteristics: there is only one obvious glow peak at 385 nm, 489 K in the TL 3D emission spectra and its TL dose response is linear-sublinear. However, there are several elementary glow peaks in the TL 3D emission spectra and their TL dose responses are linear-supralinear for SrSO4:RE3+ (RE = Dy, Tm). These TL peaks occurred from low to high temperature indicate that the traps are distributed in different energy levels. When a suitable amount of other impurities co-doped into these SrSO4:RE3+, such as phosphorus, the relative intensities of these elementary glow peaks are changed significantly, especially the TL peak ~500 K is enhanced while the peaks at lower temperature are suppressed. The enhanced peak of SrSO4:RE3+,P is attributed to the deep traps. Their dose responses remain in nonlinearity when co-doped phosphorus. The above results and the luminescence properties of other sulphate doped rare earths impurities illustrate that the TL characteristics depend on the structure of defect complexes which can be assumed the basic elements in the TL multi-stage processes.

Controlled Synthesis of Tb3+/Eu3+ Co-Doped Gd2O3 Phosphors with Enhanced Red Emission.

(Gd0.93-xTb0.07Eux)2O3 (x = 0⁻0.10) phosphors shows great potential for applications in the lighting and display areas. (Gd0.93-xTb0.07Eux)2O3 phosphors with controlled morphology were prepared by a hydrothermal method, followed by calcination at 1100 °C. XRD, FE-SEM, PL/PLE, luminescent decay analysis and thermal stability have been performed to investigate the Eu3+ content and the effects of hydrothermal conditions on the phase variation, microstructure, luminescent properties and energy transfer. Optimum excitation wavelength at ~308 nm nanometer ascribed to the 4f8-4f75d¹ transition of Tb3+, the (Gd0.93-xTb0.07Eux)2O3 phosphors display both Tb3+and Eu3+ emission with the strongest emission band at ~611 nm. For increasing Eu3+ content, the Eu3+ emission intensity increased as well while the Tb3+ emission intensity decreased owing to Tb3+→Eu3+ energy transfer. The energy transfer efficiencies were calculated and the energy transfer mechanism was discussed in detail. The lifetime for both the Eu3+ and Tb3+ emission decreases with the Eu3+ addition, the former is due to the formation of resonant energy transfer net, and the latter is because of contribution by Tb3+→Eu3+ energy transfer. The phosphor morphology can be controlled by adjusting the hydrothermal condition (reaction pH), and the morphological influence to the luminescent properties (PL/PLE, decay lifetime, etc.) has been studied in detail.

Spatial variability and geochemistry of rare earth elements in soils from the largest uranium-phosphate deposit of Brazil.

The Itataia uranium-phosphate deposit is the largest uranium reserve in Brazil. Rare earth elements (REEs) are commonly associated with phosphate deposits; however, there are no studies on the concentrations of REEs in soils of the Itataia deposit region. Thus, the objective of the research was to evaluate the concentration and spatial variability of REEs in topsoils of Itataia phosphate deposit region. In addition, the influence of soil properties on the geochemistry of REEs was investigated. Results showed that relatively high mean concentrations (mg kg-1) of heavy REEs (Gd 6.01; Tb 1.25; Ho 1.15; Er 4.05; Tm 0.64; Yb 4.61; Lu 0.65) were found in surface soils samples. Soil properties showed weak influence on the geochemical behavior of REEs in soils, except for the clay content. On the other hand, parent material characteristics, such as P and U, had strong influence on REEs concentrations. Spatial distribution patterns of REEs in soils are clearly associated with P and U contents. Therefore, geochemical surveys aiming at the delineation of ore-bearing zones in the region can benefit from our data. The results of this work reinforce the perspective for co-mining of P, U and REEs in this important P-U reserve.

The Photoluminescence Properties of CaYAI3O7:Ce³âº, Tb³âº, Sm³âº Prepared by the Sol-Gel Process.

This paper reports the synthesis and luminescence properties of rare earth doped CaYAI3O7 prepared via a sol-gel process. The phosphors have intense luminescence. In Ce³âº/Tb³âº co-doped materials, there is energy transfer from Ce³âº to Tb³âº that enhances the luminescence of Tb³âº. These materials may find applications in solid state lighting and radiation detection.

Quantifying Aflatoxin B1 in peanut oil using fabricating fluorescence probes based on upconversion nanoparticles.

Rare earth doped upconversion nanoparticles convert near-infrared excitation light into visible emission light. Compared to organic fluorophores and semiconducting nanoparticles, upconversion nanoparticles (UCNPs) offer high photochemical stability, sharp emission bandwidths, and large anti-Stokes shifts. Along with the significant light penetration depth and the absence of autofluorescence in biological samples under infrared excitation, these UCNPs have attracted more and more attention on toxin detection and biological labelling. Herein, the fluorescence probe based on UCNPs was developed for quantifying Aflatoxin B1 (AFB1) in peanut oil. Based on a specific immunity format, the detection limit for AFB1 under optimal conditions was obtained as low as 0.2ng·ml(-1), and in the effective detection range 0.2 to 100ng·ml(-1), good relationship between fluorescence intensity and AFB1 concentration was achieved under the linear ratios up to 0.90. Moreover, to check the feasibility of these probes on AFB1 measurements in peanut oil, recovery tests have been carried out. A good accuracy rating (93.8%) was obtained in this study. Results showed that the nanoparticles can be successfully applied for sensing AFB1 in peanut oil.

Fabricating a novel label-free aptasensor for acetamiprid by fluorescence resonance energy transfer between NH2-NaYF4: Yb, Ho@SiO2 and Au nanoparticles.

Rare earth-doped upconversion nanoparticles have promising potential in the field of pesticide detection because of their unique frequency upconverting capability and high detection sensitivity. This paper reports a novel aptamer-based nanosensor for acetamiprid detection using fluorescence resonance energy transfer (FRET) between NH2-NaYF4: Yb, Ho@SiO2 (UCNPs) and gold nanoparticles (GNPs). Herein, GNPs as acceptors efficiently quench the fluorescence of UCNPs and acetamiprid specifically interacts with acetamiprid binding aptamer (ABA), causing the conformation changes of ABA from random coil to hairpin structure. Accordingly, ABA no longer stabilizes the GNPs in salt solution, leading to the varying aggregation extent of GNPs. Thus, the fluorescence of UCNPs are proportionally recovered. Under the optimized conditions, the enhancement efficiency was observed to increase linearly with the concentration of acetamiprid from 50 nM to 1000 nM, resulting in a relatively low limit of 3.2 nM. Additionally, the aptasensor demonstrated high selectivity to similar structure pesticides such as imidacloprid and chlorpyrifos, and further confirmed its application capacity in adulterated tea samples.

Characterization of PM2.5 and PM10 fugitive dust source profiles in the Athabasca Oil Sands Region.

UNLABELLED: Geological samples were collected from 27 representative locations in the Athabasca Oil Sands Region (AOSR) in Alberta, Canada. These samples were resuspended onto filter substrates for PM2.5 and PM10 size fractions. Samples were analyzed for 229 chemical species, consisting of elements, ions, carbon, and organic compounds. These chemical species are normalized to gravimetric mass to derive individual source profiles. Individual profiles were grouped into six categories typical of those used in emission inventories: paved road dust, unpaved road dust close to and distant from oil sand operations, overburden soil, tailings sands, and forest soils. Consistent with their geological origin, the major components are minerals, organic and elemental carbon, and ions. The sum of five major elements (i.e., Al, Si, K, Ca, and Fe) and their oxidized forms account for 25-40% and 45-82% of particulate matter (PM) mass, respectively. Si is the most abundant element, averaging 17-18% in the Facility (oil sand operations) and 23-27% in the Forest profiles. Organic carbon is the second most abundant species, averaging 9-11% in the Facility and 5-6% in the Forest profiles. Elemental carbon abundance is 2-3 times higher in Facility than Forest profiles. Sulfate abundance is ~7 times higher in the Facility than in the Forest profiles. The ratios of cation/anion and base cation (sum of Na+, Mg2+, K+, and Ca2+)/nitrogen- and sulfur-containing ions (sum of NH4+, NO2-, NO3-, and SO4(2-)) exceed unity, indicating that the soils are basic. Lead (Pb) isotope ratios of facility soils are similar to the AOSR stack and diesel emissions, while those of forest soils have much lower 206Pb/207Pb and 208Pb/207Pb ratios. High-molecular-weight n-alkanes (C25-C40), hopanes, and steranes are more than an order of magnitude more abundant in Facility than Forest profiles. These differences may be useful for separating anthropogenic from natural sources of fugitive dust at receptors. IMPLICATIONS: Several organic compounds typical of combustion emissions and bitumen are enriched relative to forest soils for fugitive dust sources near oil sands operations, consistent with deposition uptake by biomonitors. AOSR dust samples are alkaline, not acidic, indicating that potential acid deposition is neutralized. Chemical abundances are highly variable within emission inventory categories, implying that more specific subcategories can be defined for inventory speciation.

Luminescent and transparent nanopaper based on rare-earth up-converting nanoparticle grafted nanofibrillated cellulose derived from garlic skin.

Highly flexible, transparent, and luminescent nanofibrillated cellulose (NFC) nanopaper with heterogeneous network, functionalized by rare-earth up-converting luminescent nanoparticles (UCNPs), was rapidly synthesized by using a moderate pressure extrusion paper-making process. NFC was successfully prepared from garlic skin using an efficient extraction approach combined with high frequency ultrasonication and high pressure homogenization after removing the noncellulosic components. An efficient epoxidation treatment was carried out to enhance the activity of the UCNPs (NaYF4:Yb,Er) with oleic acid ligand capped on the surface. The UCNPs after epoxidation then reacted with NFC in aqueous medium to form UCNP-grafted NFC nanocomposite (NFC-UCNP) suspensions at ambient temperature. Through the paper-making process, the assembled fluorescent NFC-UCNP hybrid nanopaper exhibits excellent properties, including high transparency, strong up-conversion luminescence, and good flexibility. The obtained hybrid nanopaper was characterized by transmission electron microscopy (TEM), atomic force microscope (AFM), Fourier transform infrared spectroscopy (FTIR), field emission-scanning electron microscope (FE-SEM), up-conversion luminescence (UCL) spectrum, and ultraviolet and visible (UV-vis) spectrophotometer. The experimental results demonstrate that the UCNPs have been successfully grafted to the NFC matrix with heterogeneous network. And the superiorly optical transparent and luminescent properties of the nanopaper mainly depend on the ratio of UCNPs to NFC. Of importance here is that, NFC and UCNPs afford the nanopaper a prospective candidate for multimodal anti-counterfeiting, sensors, and ion probes applications.

Rare earth elements recycling from waste phosphor by dual hydrochloric acid dissolution.

This paper is a comparative study of recycling rare earth elements from waste phosphor, which focuses on the leaching rate and the technical principle. The traditional and dual dissolution by hydrochloric acid (DHA) methods were compared. The method of dual dissolution by hydrochloric acid has been developed. The Red rare earth phosphor (Y0.95Eu0.05)2O3 in waste phosphor is dissolved during the first step of acid leaching, while the Green phosphor (Ce0.67Tb0.33MgAl11O19) and the Blue phosphor (Ba0.9Eu0.1MgAl10O17) mixed with caustic soda are obtained by alkali sintering. The excess caustic soda and NaAlO2 are removed by washing. The insoluble matter is leached by the hydrochloric acid, followed by solvent extraction and precipitation (the DHA method). In comparison, the total leaching rate of the rare earth elements was 94.6% by DHA, which is much higher than 42.08% achieved by the traditional method. The leaching rate of Y, Eu, Ce and Tb reached 94.6%, 99.05%, 71.45%, and 76.22%, respectively. DHA can decrease the consumption of chemicals and energy. The suggested DHA method is feasible for industrial applications.

Effects of exogenous rare earth elements on phosphorus adsorption and desorption in different types of soils.

Phosphorus (P) is an important biogeochemical element and the environmental fate of P receives increasing attention. Through batch equilibration experiments, the adsorption and desorption of P in the absence and presence of exogeneous rare earth elements (REEs) were investigated in five types of agricultural soil samples collected from China. The results showed that the addition of different doses of REEs had influences on P adsorption processes in the soils, and there were differences in different soil types and different P concentrations of the P solutions. The amount of P adsorption tended to decline when the five types of soils were amended with low concentrations of REEs. The characteristics of P adsorption were more complicated when high concentrations of REEs were added to the different soils. Affected by the high concentrations of REEs, when the P concentration of the P solution added to soils was less than 20 mg L(-1), the rate of P adsorption tended to increase in all the five types of soils. However, when the P concentration of the P solution added to soil was greater than 30 mg L(-1), the rate of P adsorption tended to decrease. The Langmuir equation fitted P adsorption in all the five types of soils well. Compared with the control, when soil samples were amended with REEs, the P desorption rates of the five types of soils increased.

An experimental study on using rare earth elements to trace phosphorous losses from nonpoint sources.

Controlling phosphorous (P) inputs through management of its sources and transport is critical for limiting freshwater eutrophication. In this study, characteristics of exogenous rare earth elements (REEs) and P and their losses with surface runoff (both in the water and sediments) during simulated rainfall experiments (83 mm h⁻¹) were investigated. The results revealed that on average most REEs (La, 94%; Nd, 93%; Sm, 96%) and P (96%) transported with sediments in the runoff. The total amounts of losses of REEs and P in the runoff were significantly correlated, suggesting the possibility of using REEs to trace the fate of agricultural nonpoint P losses.