Sample Surface Research Articles

Tribological behaviors and wettability evolution of phenolic resin-impregnated graphite materials under water immersion condition

This study investigated the tribological behaviors of two phenolic resin-impregnated graphite samples and one non-impregnated sample under dry and water immersion using a reciprocating testing device. The frictional configuration involved a steel hemisphere sliding against the surface of the graphite samples. The influence of water immersion time before each formal test on friction coefficients was discussed. The wettability evolution during the test processes and the difference in porosity, which could significantly affect water infiltrating into the sample matrix and frictional interfaces, were associated with the variation in tribological behaviors. The worn surface morphology and element analysis results indicated that the shallow valleys and pores on the surface of graphite were gradually filled by wear debris from both the graphite samples and the harder counterpart. Based on these experimental results, a tribological mechanism of the phenolic resin-impregnated graphite materials under water immersion was developed.

Laser-induced breakdown spectroscopy as a method for millimeter-scale inspection of surface flatness

A non-contact method for millimeter-scale inspection of material surface flatness via Laser-Induced Breakdown Spectroscopy (LIBS) is investigated experimentally. The experiment is performed using a planished surface of an alloy steel sample to simulate its various flatness, ranging from 0 to 4.4 mm, by adjusting the laser focal plane to the surface distance with a step length of 0.2 mm. It is found that LIBS measurements are successful in inspecting the flatness differences among these simulated cases, implying that the method investigated here is feasible. It is also found that, for achieving the inspection of surface flatness within such a wide range, when univariate analysis is applied, a piecewise calibration model must be constructed. This is due to the complex dependence of plasma formation conditions on the surface flatness, which inevitably complicates the inspection procedure. To solve the problem, a multivariate analysis with the help of Back-Propagation Neural Network (BPNN) algorithms is applied to further construct the calibration model. By detailed analysis of the model performance, we demonstrate that a unified calibration model can be well established based on BPNN algorithms for unambiguous millimeter-scale range inspection of surface flatness with a resolution of about 0.2 mm.

Influence of riboflavin on the corrosion of X80 pipeline steel by Sulfate reducing bacteria

Abstract The sulfate reducing bacteria(SRB) is commonly attached to the surface of buried pipeline steel, and the electron shuttle in the corrosion medium can promote the release of electrons from iron oxidation through the bacterial cell wall into the cytoplasm to accelerate the corrosion of anode iron. This study investigated the impact of riboflavin (RF) as an endogenous electron shuttle on the corrosion behavior of X80 pipeline steel in SRB system. The findings indicated that while the type of corrosion products remains unchanged in samples under SRB+10mg/L RF system, there was an expansion in both area and depth of corrosion pits on the sample surface, resulting in a corrosion loss rate approximately 3 times higher than that observed in SRB system. Furthermore, the polarization resistance (Rp) value of the sample in SRB system is about 2~5 times that of the sample in SRB+10 mg/L RF system. Additionally, the corrosion current density of X80 pipeline steel samples soaked in SRB and SRB+10 mg/L RF system for 14 days is 9.31×10-6 A·cm-2 and 1.28×10-5 A·cm-2, and the addition of 10 mg/L RF increases the corrosion current density of SRB system by about 37.49%. These results indicated that the reaction resistance of SRB-induced MIC in X80 pipeline steel was significantly reduced due to the presence of RF.

Development of Lead‐Free Defect Brownmillerite Perovskite Ceramic LiBiFeMnO5 Solid Solution for Electronic Devices

This article reports the fabrication (synthesis) and characterizations (structural, microstructural topographic surface, dielectric, transport, impedance, current–voltage, and resistive properties) of a complex lead‐free defect perovskite material of composition LiBiFeMnO5. A preliminary structural investigation of the X‐ray diffraction pattern using N‐TREOR09 methods shows monoclinic symmetry. The scanning electron microscopic spectrum examines the sample's microstructural topographic surface, fractal study, and roughness (using the standard ISO25178). The analysis of Maxwell–Wagner dielectric dispersion, relaxation, and transport mechanisms is investigated utilizing dielectric, impedance, and conductivity spectrum accumulated within the experimental frequency of (1 kHz–1 MHz) at different temperatures (30–500 °C). A nonoverlapping small polaron tunneling conduction mechanism and correlated barrier hopping mechanism in the material have helped to understand its conduction phenomena. The Ohmic and space–charge limited conduction mechanisms are investigated by the slope of the logarithmic electric field (E) and current density (J). The thermistor constant (β) is determined to be 1982.87. The temperature coefficient of resistance is found to be −0.00419, which may be suitable for negative temperature coefficient thermistors, sensors, and other related devices.

Evaluation of some techniques for drying conidiated rice culture of the entomopathogenic fungus Beauveria bassiana (Bals.) Vuill. with a bioassay evaluating their eligibility

BackgroundProduction of entomopathogenic fungi on a solid substrate, mostly on rice, is preferred by many producers due to its low technological requirements. Drying may be needed after fermentation to preserve the viability of the conidia until use. This study aimed to introduce some uncomplicated drying techniques and study their effectiveness in terms of drying time and extent, as well as their impact on the quantity of conidia produced and their biological activity. Four techniques were studied, i.e., condensing water vapor (by cooling), desiccant (using NaOH), air drying on a net, and air drying on a solid (impermeable) surface.ResultsCondensing water vapor and desiccant techniques were the fastest and most efficient, resulting in the lowest moisture content, ranging between 12 and 13%. While drying on a solid surface was the slowest and resulted in the highest moisture content of 32.98%. All of the dried samples yielded a lower quantity of conidia compared to the fresh samples. Samples of condensing water vapor, desiccant, and net techniques yielded approximately a similar quantity of conidia, ranging between 74 and 71% of the yield of the fresh sample. The solid surface sample yielded the lowest quantity of conidia, representing 63.78% of the fresh sample yield. A bioassay test on the mite, Tetranychus urticae Koch (Acari: Tetranychidae), showed that conidia dried via condensing water vapor and desiccant techniques kept their pathogenicity similar to the fresh sample, while samples dried on a net and solid surface significantly lost part of their pathogenicity.ConclusionThe condensing water vapor and desiccant techniques were the most efficient regarding the time needed, conidia yield, and pathogenicity. Drying on a solid surface was the least effective regarding the same factors.

16S rRNA amplicon sequencing and antimicrobial resistance profile of intensive care units environment in 41 Brazilian hospitals

IntroductionInfections acquired during healthcare setting stay pose significant public health threats. These infections are known as Healthcare-Associated Infections (HAI), mostly caused by pathogenic bacteria, which exhibit a wide range of antimicrobial resistance. Currently, there is no knowledge about the global cleaning process of hospitals and the bacterial diversity found in ICUs of Brazilian hospitals contributing to HAI.ObjectiveCharacterize the microbiome and common antimicrobial resistance genes present in high-touch Intensive Care Unit (ICU) surfaces, and to identify the potential contamination of the sanitizers/processes used to clean hospital surfaces.MethodsIn this national, multicenter, observational, and prospective cohort, bacterial profiles and several antimicrobial resistance genes from 41 hospitals across 16 Brazilian states were evaluated. Using high-throughput 16S rRNA amplicon sequencing and real-time PCR, the bacterial abundance and resistance genes presence were analyzed in both ICU environments and cleaning products.ResultsWe identified a wide diversity of microbial populations with a recurring presence of HAI-related bacteria among most of the hospitals. The median bacterial positivity rate in surface samples was high (88.24%), varying from 21.62 to 100% in different hospitals. Hospitals with the highest bacterial load in samples were also the ones with highest HAI-related abundances. Streptococcus spp., Corynebacterium spp., Staphylococcus spp., Bacillus spp., Acinetobacter spp., and bacteria from the Flavobacteriaceae family were the microorganisms most found across all hospitals. Despite each hospital particularities in bacterial composition, clustering profiles were found for surfaces and locations in the ICU. Antimicrobial resistance genes mecA, blaKPC-like, blaNDM-like, and blaOXA-23-like were the most frequently detected in surface samples. A wide variety of sanitizers were collected, with 19 different active principles in-use, and 21% of the solutions collected showed viable bacterial growth with antimicrobial resistance genes detected.ConclusionThis study demonstrated a diverse and spread pattern of bacteria and antimicrobial resistance genes covering a large part of the national territory in ICU surface samples and in sanitizers solutions. This data should contribute to the adoption of surveillance programs to improve HAI control strategies and demonstrate that large-scale epidemiology studies must be performed to further understand the implications of bacterial contamination in hospital surfaces and sanitizer solutions.

Wetsuit Thermal Resistivity Measurements

In recent years, attention to the realization and characterization of wetsuits for scuba diving and other sea sports or activities has increased. The research has aimed to establish reliable and standardized measurement methods to objectively assess wetsuit quality, particularly focusing on their mechanical and thermal properties. In this work, we describe and compare two different measurement methods for the characterization of neoprene wetsuit thermal resistivity. The first method follows the existing regulations in the field, while the second one, which we are originally proposing in this paper, offers an alternative yet accurate way based on a simplified experimental set-up and easier measurements. In both cases, the wetsuit sample under testing was shaped in the form of a cylindrical sleeve of proper dimensions and wrapped around a phantom containing water at a higher temperature and surrounded by water at a lower temperature. The wetsuit’s cylindrical surface allows heat flow from the warmer water on the inside to the colder water on the outside through the wetsuit area. In the first case, a thermal steady state was achieved, with constant heat flow from the phantom to the exterior. This was obtained with a power balance between two homogenous quantities. Electrically supplied thermal heating within the phantom was used to balance the thermal energy naturally flowing through the wetsuit’s surface. In this first case, a stable and fixed temperature difference was obtained between the inner and the outer surfaces of the wetsuit sample. In the second case, a thermal transient was analyzed during the cooling process of the phantom, and the thermal time constant was measured, providing the sample thermal resistance once the phantom thermal capacity was known. In both cases and methods, the heat flow and thermal resistance of other elements than the wetsuit must be evaluated and compensated for if they are not negligible. Finally, the thermal resistivity per unit area of the wetsuit material was obtained with the product of the wetsuit sample’s thermal resistance and the wetsuit area. The measurements, conducted until now by immersing the phantom in a free surface tank, show that both methods—under stationary and under transient temperature conditions—were valid to assess the wetsuit’s thermal resistivity. The stationary method somehow provided better accuracy while involving less well-known parameters but at the expense of a more complicated experimental set-up and additional energy consumption. The transitory method, on the other hand, is quite easy to implement and, after careful characterization of the phantom’s parameters, it provided similar results to the stationary one. An uncertainty budget was evaluated for both methods, and they did provide highly compatible measurement results, with resistivity values of 0.104(9) m2·K/W (stationary method) and 0.095(9) K·m2/W (transient method) for the same wetsuit sample under testing, which is also consistent with the values in the literature. We finally propose that the novel method is a valid alternative for characterization of the thermal insulation properties of a scuba diving wetsuit.

Quantitative prediction of the flammability limits of filter paper in microgravity conditions

Under JAXA's FLARE project, ongoing since May 2022, long-duration microgravity combustion experiments have been conducted using filter paper. These experiments utilize the Solid Combustion Experiment Module (SCEM) in the ISS/Kibo module. The dimensions of the filter paper used were 130 mm in length and either 40 mm or 20 mm in width, with the experiments conducted in an environment of 298 K and 100 kPa. This paper highlights the results of 19 flame spread experiments performed in opposed-flow environments and compares the predetermined flammability limiting curve with the flammability map obtained in orbital experiments. One of the objectives of the FLARE project is to predict the flammability limiting curve in microgravity environments based on the results of tests that can be conducted on the ground. These experiments produced intriguing findings, demonstrating the effects of both radiation loss and blow-off during flame spread, as the opposed flow velocity was incrementally increased from 10 cm/s to 18 cm/s in 2 cm/s steps, within an environment containing 15.5 % oxygen concentration. When comparing with the combustible map obtained from orbital experiments, it was discovered that the original limit curve accurately replicated the blow-off branch but overestimated the flammable region in areas with opposed-flow velocity below 10 cm/s. This discrepancy was attributed to the inadequate consideration of the effect of opposed-flow velocity on the radiation quenching branch. Therefore, by considering the velocity distribution measurement results obtained in orbit and modeling the impact of the effective flow velocity opposing the flame front on both the radiation quenching branch and the blow-off branch, we successfully quantitatively replicated the results of the orbital experiments. These findings indicate that the flammability limits of thin flat plate samples can be accurately predicted by properly assessing the effect of the boundary layer on the sample surface.

Assessment of microplastics pollution level on clam farming and bathing beaches: a case study of Thanh Phu in Ben Tre, Vietnam

ABSTRACT This study focused on the investigation microplastics (MPs) with a size of ≤1.0 mm in sand samples from Thanh Phu beach, Ben Tre, Vietnam. MPs in sand from the clam beach (from 39.67 ± 6.67 to 92.00 ± 12.93 items kg−1 dried sand) were higher than those from the bathing beach (from 21.33 ± 8.76 to 51.67 ± 16.11 items kg−1 dried sand), indicating a direct contribution of MPs from coastal aquaculture. For the clam beach, MPs in surface samples (0–4 cm) were lower than in deep samples (4–6 cm). In contrast, MPs in surface samples (0–2 cm) from the bathing beach were higher than deep samples (2–5 cm). A combination of microscopy and Fourier-transform infrared spectroscopy methods confirmed that 62.5% of the representative MPs samples or 18.9% of the suspected MPs samples were plastics. Low-density polyethylene, polypropylene and polyethylene terephthalate were the largest in abundance. Further studies are needed to assess the environmental risk of MPs accumulation.

Addition of a Novel Qualitative Technique to Standard Quantitative Practices for Evaluation of Hazardous Drug Exposure in a Canadian Hospital Setting.

Current recommendations from regulatory authorities suggest quantitative surface sampling for detection of hazardous drugs at least once every 6 months. A more frequent and efficient process for hazardous drug testing might reduce the safety risks associated with exposure to these agents. The primary objective was to assess the findings of surface testing based on traditional quantitative sampling methods relative to the findings of qualitative surface sample testing with the BD HD Check system. The secondary objectives included assessment of the ease of integrating qualitative sampling into pharmacy protocols and identification of opportunities to enhance patient and staff education and safety. Samples from 23 unique surfaces were tested concurrently once a month for 5 months using a quantitative surface sampling method and the qualitative BD HD Check system on adjacent 12 inch × 12 inch (30.5 cm × 30.5 cm) surface areas. The presence or absence of cyclophosphamide, methotrexate, and/or doxorubicin contamination was assessed by each of the 2 testing methods. The BD HD Check system was also assessed for ease of use and efficiency. Ten areas of contamination were identified over the 5-month period. Nine were detected by the BD HD Check system and one by the quantitative system. The BD HD Check system was easy to use, with results available in less than 10 minutes per area tested. The BD HD Check system allows for more timely identification of surface contamination with hazardous drugs than the standard sampling protocol. The discrepancy in results between the 2 methods of hazardous drug surface sampling requires further investigation.

Surface segregation phenomena encountered during solid carbon active screen plasma nitrocarburizing of AISI 316L

Plasma nitrocarburizing of an austenitic stainless steel AISI 316L was performed in an N2-H2 atmosphere (50 % H2 and 50 % N2) with a carbon-fiber reinforced carbon (CFC) active screen. The experimental concept of a plasma-discharged CFC active screen in conjunction with a substrate holder at floating potential ensures that no charged particles are present on the sample surface and no sputtering occurs. As a result, carbon contaminations are formed on the surface which were studied in detail with a combination of scanning electron microscopy (SEM) and secondary ion mass spectrometry (SIMS). The results indicate that a layer of about 25–50 nm of carbon is formed. At the same time, a strong segregation of Mn, Ni and Cr is observed below the coating within the steel substrate. Both effects progress with treatment time and there exists a clear correlation between the formation of the carbon layer and the segregation effect.

The evolution of microstructure and mechanical properties of Inconel 625 alloy fabricated by laser powder bed fusion via novel hybrid scanning strategy

Four innovative hybrid scanning strategies (0° + 67°, 45° + 67°, 67° + 67° and 90° + 67°) of laser powder bed fusion (LPBF) have been proposed to tailor the microstructure and mechanical properties of Inconel 625 alloy for the first time. The experiment results revealed in sample I (0° + 67°) and sample IV (90° + 67°) a gradient structure is formed, progressing from randomly textured slender columnar crystals (001) to randomly textured equiaxial fine crystals, and finally to equiaxial and fine columnar crystals. In samples II (45° + 67°) and III (67° + 67°), isometric and columnar crystals are uniformly distributed throughout the sample. The tensile strengths of samples treated via hybrid scanning strategy in LPBF (sample I: 1270 ± 8 MPa, sample II: 1400 ± 6 MPa, sample III: 1390 ± 5 MPa and sample IV: 1360 ± 5 MPa) surpassed those of conventionally manufactured samples, including Inconel 625 alloy fabricated by LPBF using a single scanning strategy. This superiority can be attributed to the presence of fine grains, elevated residual stress levels, and the formation of stacking faults. The results of the nanoscratch test reveal that the bottom surface of samples I and IV demonstrates superior abrasion resistance in comparison to the top surface, which can be attributed to the higher relative density, finer grain size, lower elastic modulus and lower Schmidt factors in the bottom surface. These findings hold significant implications for tailoring the microstructure and properties of Inconel 625 alloy, especially in the realm of additively manufactured materials featuring heterogeneous structures.

NIR-triggered arsenic-loaded layered double hydroxide-based films for localized thermal synergistic chemotherapy

Portal vein tumor thrombus (PVTT) formed by cancer cell invasion is a major cause of high mortality in hepatocellular carcinoma (HCC), and the formation of thrombus will be accelerated by bacterial colonization on the surface of the implant after surgery. In this work, Polypyrrole-coated arsenic-loaded layered double hydroxide films were in situ constructed on the nickel-titanium alloy for the efficient killing of tumour cells by thermo-therapeutic synergistic chemotherapy. The good near-infrared photothermal conversion ability of polypyrrole enables the sample surface temperature to be raised to about 51 °C at a low photothermal power (0.5 w/cm2), while the elevated temperature could further accelerate the release of drug arsenic. In addition, when NIR light is not applied, the polypyrrole coating also cleverly acts as a “barrier layer” to reduce the natural release of arsenic in normal tissues to avoid toxicity issues. In vivo and in vitro experiments have demonstrated that the platform exhibits excellent antitumor and antibacterial abilities. In contrast to the systemic toxicity issues associated with systemic circulation of nanotherapeutic drugs, this in situ functional film is expected to be used in localised interventions for precise drug delivery, and is also more suitable for surgical treatment scenarios in PVTT surgeries.

Step-by-step in-situ preparation of magnesium-aluminum layered double hydroxide film to improve the corrosion resistance of AZ31 magnesium alloy

In this study, a hydrothermal method was employed to cultivate Mg(OH)2 precursor layers on the surface of AZ31 magnesium alloy samples. Subsequently, Mg-Al LDHs films were successfully synthesized through an in-situ growth approach. The phase composition of the films were analyzed using X-ray diffraction and infrared spectroscopy. The growth process and surface morphology of the films at the microstructure level were examined and interpreted using scanning electron microscopy and EDS. The corrosion resistance of the films was assessed through potentiodynamic polarization curves, electrochemical impedance spectroscopy, and hydrogen evolution tests. The findings indicate that the Mg(OH)2 precursor effectively mitigates defects in the Mg-Al LDHs films and improves the LDHs microstructure. Moreover, the precursor synthesized at a pH range of 10–12 better enhances the corrosion resistance of the Mg-Al LDHs film.

Microstructural analysis of ex-service neutron irradiated stainless steel nuclear fuel cladding by high-speed AFM

Fuel cladding in advanced gas-cooled nuclear reactors is made of an austenitic stainless steel referred to as 20Cr/25NiNb. This material can undergo microstructural changes in these extreme environments through a combination of thermal effects and radiation damage. In this work, the microstructures present in an ex-service irradiated 20Cr/25Ni-Nb sample are studied using correlated high-speed atomic force microscopy (HS-AFM) and electron microscopy techniques for the first time. Correlated topographic, crystallographic, and chemical information from the sample surface enabled identification of secondary phase precipitates (SPPs) including M23C6, sigma phase, NbC, and G phase. These SPPs can have adverse effects on the material properties. HS-AFM analysis showed surface textures unique to each SPP. Voids formed due to irradiation were also identified across the surface by HS-AFM. These voids were found to be larger in size and depth along grain boundaries. Further analysis identified a relationship between void size and frequency and grain boundary misorientation and SPP presence.

Microstructural Analysis of Ex-Service Neutron Irradiated Stainless Steel Nuclear Fuel Cladding by High-Speed AFM

Fuel cladding in advanced gas-cooled nuclear reactors is made of an austenitic stainless steel referred to as 20Cr/25NiNb. This material can undergo microstructural changes in these extreme environments through a combination of thermal effects and radiation damage. In this work, the microstructures present in an ex-service irradiated 20Cr/25Ni-Nb sample are studied using correlated high-speed atomic force microscopy (HS-AFM) and electron microscopy techniques for the first time. Correlated topographic, crystallographic, and chemical information from the sample surface enabled identification of secondary phase precipitates (SPPs) including M23C6, sigma phase, NbC, and G phase. These SPPs can have adverse effects on the material properties. HS-AFM analysis showed surface textures unique to each SPP. Voids formed due to irradiation were also identified across the surface by HS-AFM. These voids were found to be larger in size and depth along grain boundaries. Further analysis identified a relationship between void size and frequency and grain boundary misorientation and SPP presence.

Biosynthesis, Structural, Spectroscopic, Photoluminescence, and Antifungal Activity of Ni-doped CeO2 Nanoparticles.

Pedalium Murex leaf extract was used in this study to create Nickel-doped Cerium oxide (Ni-CeO2) nanoparticles at 3mol% and 5mol% molar concentrations. The biosynthesized process was applied for the fabrication of Ni-CeO2 NPs. The X-ray diffraction method was used to identify their crystal structure. The XRD measurements showed that the Ni-CeO2 NPs crystallized into the face-centred cubic system. Fourier transform infrared spectral study was applied to explore the molecular vibrations and chemical bonding. The surface texture and chemical ingredients of Ni-CeO2 NPs were studied using field-emission scanning electron microscopy and energy-dispersive X-ray analysis. The EDX mapping spectra illustrate the uniform dispersal of Ce, Ni, and O atoms over the sample's surface. X-ray photoelectron spectroscopy (XPS) was conducted to confirm the chemical state of the Ni-CeO2 NPs. UV-Vis spectrum study was performed to ascertain the photon absorption, bandgap, and Urbach edge of Ni-CeO2 NPs. Photoluminescence (PL) research has been used to study the light-emitting characteristic of Ni-CeO2 NPs. The emissive intensity transition corresponding to Ni-CeO2 NPs was found to increase with the dopant level. The CIE 1931 chromaticity map was plotted to find the aptness of the samples for optical uses.The antifungal ability of Ni-CeO2 NPs was evaluated against the fungi candida albicans and candida krusein with the agar well-diffusion process. The fungicidal activity of the 3mol% Ni doped CeO2 nanoparticles has shown a maximum zone of inhibition. The experimental findings illustrate the utility of Ni-CeO2 NPs for optical and antifungal applications.

Topographic analysis of fiber posts after surface disinfection with different methods

Aims: This study aims to comprehensively examine the surface morphology of fiber posts after undergoing various disinfection methods, utilizing scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Materials and Methods: Twenty-one fiber posts were randomly allocated into seven experimental groups, each consisting of three samples. The disinfection methods employed were as follows: GC - no disinfection treatment; GAL - immersion in 70% alcohol, following the manufacturer's recommended protocol; GHP - soaking in 2.5% sodium hypochlorite for a duration of 10 minutes; GCL - soaking in 2% chlorhexidine gluconate for a period of five minutes; GAC - 30-second etching with 35% phosphoric acid; GPH - soaking in 10% hydrogen peroxide for a duration of 20 minutes; and GSL - autoclave sterilization. Following the disinfection procedures, SEM was employed to scrutinize the surface topography of the posts, while EDX was utilized to identify the chemical elements present on the sample surfaces. Subsequently, a descriptive analysis was conducted on the SEM images and EDX data. Results: SEM analysis revealed that all groups exhibited regions with epoxy resin-coated fibers alongside sections with exposed glass fibers. Analysis of the EDX data indicated that there were no significant differences in the predominant chemical elements across the groups. Carbon (C) and oxygen (O) registered the highest peaks, followed by silicon (Si), zirconium (Zr), sodium (Na), aluminum (Al), and calcium (Ca). Conclusions: The disinfection methods under investigation did not induce substantial alterations in the surface morphology of the fiber posts.

Temporal Analysis of Pharmaceuticals as Emerging Contaminants in Surface Water and Wastewater Samples: A Case Study

Pharmaceuticals in the environment are a global concern, with studies in all continents highlighting their widespread occurrence and potential ecological impacts, revealing their presence, fate, and associated risks in aquatic ecosystems. Despite typically occurring at low concentrations (ranging from ng/L to µg/L), advancements in analytical methods and more sensitive equipment have enabled the detection of a higher number of pharmaceuticals. In this study, surface and wastewater samples were extracted using solid phase extraction and analyzed using ultra-high-performance liquid chromatography with tandem mass spectrometry. Among the therapeutic classes investigated, nonsteroidal anti-inflammatory drugs/analgesics, antibiotics, and psychiatric drugs showed a higher number of detected pharmaceuticals. Concentrations ranged from below method detection limit (<MDL) to 3.20 µg/L (caffeine) and <MDL to 639 µg/L (hydroxyibuprofen) in 2018, and from <MDL to 0.848 µg/L (diclofenac) and <MDL to 53.0 µg/L (caffeine) in 2019 for river water and wastewater samples. Temporal analysis showed an increase in the sum of pharmaceutical concentrations over the study years, highlighting the importance of monitoring pharmaceuticals in the environment and their potential accumulation over time.

Detecting element migration from ore systems: A laser ablation ICP-MS method for the in-situ measurement of element contents and 207 Pb/ 206 Pb values on rough fracture coatings

In-situ elemental content and 207 Pb/ 206 Pb values in three rough fracture coatings within drill cores from the McArthur River unconformity-related uranium deposit, Athabasca Basin, Canada were measured using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) image mapping. Fracture coating samples were located proximal and distal to the ore deposit. Samples required minimal preparation in this method, with areas (∼500 by 500 μ m) targeted in a cell spaced grid pattern using a 50- μ m spot, spaced 200 μ m on the x- and y-axis with an offset of 100 μ m, to overcome sample surface topography. A five second (s) acquisition time was applied to elemental content measurements and a 2-s acquisition time was applied to 207 Pb/ 206 Pb measurements. These parameters increased the spatial resolution, analytical sensitivity, and minimized the contribution of the host rock underlying the fracture surface to the geochemical signal in comparison to extended acquisition times. In addition, laser ablation temporal profiles allow for the interpretation of the timing of element/isotope migration and fixation on the rough fracture coating. Rasterized maps generated in Iolite TM v.4 demonstrate the chemical distribution of elements and 207 Pb/ 206 Pb values on the rough fracture coatings, allowing for the identification of mineral phases hosting pathfinder elements, pathfinder element associations, and the generation of bulk in-situ or specific mineralogy geochemical values. Bulk in-situ values calculated using an integration of the 2D image data and targeting the ∼500 by 500 μ m surface of the fracture coating compared to previous bulk geochemical methods obtained by sampling the fracture coating with a micro drill (i.e., modified aqua regia (HCl: HNO 3 : H 2 O), weak acid leach (WAL) (2% HNO 3 )), highlights that in-situ analysis greatly improved detection of pathfinder elements on the fracture surface. This study is the first application of in-situ LA-ICP-MS for measuring element contents and 207 Pb/ 206 Pb values on rough fracture coatings and demonstrates its importance as a new geochemical tool to the mining industry for future mineral exploration.