Search Results (1,815)

Material extrusion 3D printing has been widely used in industrial, educational and residential environments. However, the associated emissions and exposure health impacts need to be evaluated, especially for the new and emerging filament materials. This study characterized particle and chemical emissions from 3D printing using five different metal composite filaments, which contain over 90% (by weight) of metal powder blended with polymer binders. The emission characterization was conducted using an exposure chamber following a standard testing method. Real-time particle measurements showed that particle emission rates ranged from 8 × 10⁹ to 2 × 10¹¹ particles/h for particle number and 200 to 1400 µg/h for particle mass. Over 98% of the emitted particles were smaller than 1 µm, which poses an inhalation hazard. Inductively coupled plasma–mass spectrometry analysis detected manganese, copper, zinc, and selenium in emitted particles from all filaments. However, metal powder in raw filaments tended not to be transferred into particle emissions, resulting in the total metals (and metalloids) accounting for 0.07% to 0.95% of emitted particle mass. Sorbent tube sampling and analytical analyses showed various volatile organic compounds emitted during printing, including hydrocarbons, alcohols, aldehydes, and aromatic compounds. Overall, metal composite filaments generated lower levels of volatile organic compounds (VOCs) compared to thermoplastic polymer filaments; in addition, the emitted VOC compositions differed. Organic chemicals associated with metal composite filament emissions included formaldehyde, benzaldehyde, acetaldehyde, naphthalene, and trimethylbenzene, exposure to which may cause irritations or other adverse health impacts. This study estimated personal exposure to hazardous components assuming a person is close to the printer with low ventilation to represent an acute worst-case exposure scenario. Modeled personal exposure to emissions showed potential exceedances of exposure to fine (PM_2.5) and coarse (PM₁₀) particulate matter, arsenic, manganese, formaldehyde, caprolactam, acetaldehyde, and naphthalene compared to reference levels. A modeled office room with ventilation showed reduced exposure levels by up to two orders of magnitude, assuming the same emission source. Users can avoid close proximity to an operating printer and increase dilution through larger room volumes and higher air change rates to reduce potential inhalation exposures at given printing conditions. Full article

Mineral elements affect tea nutritional and flavor quality, but systematic research on their dissolution behavior and links to volatile and taste profiles in Dahongpao tea is lacking, as is evidence regarding contribution to mineral intake for different populations. In this study, nine Dahongpao teas were brewed five times. Eleven elements were measured by inductively coupled plasma mass spectrometry (ICP-MS) with first-order kinetic fitting; volatile profiles were analyzed by electronic nose and taste attributes by electronic tongue; the contribution of tea infusions to dietary reference intakes was estimated from Chinese Dietary Reference Intakes (2023). The results showed that electronic nose analysis revealed distinct variation in volatile compound classes among the nine samples, with broad range and sulfur–organic compounds showing the highest response intensities. Electronic tongue analysis showed clear differences in taste profiles, particularly in astringency, umami, and sweetness, across the nine samples. Regarding dissolution behavior, Mg had the highest dissolution rate (67.24–70.94%), while Fe, Ca, K, and Zn were below 10%; dissolution followed first-order kinetics and total dissolved amounts correlated with total contents except for Fe. Network analysis integrating element data with volatile and taste profiles demonstrated that Mg and Mo contents were positively correlated with multiple volatile classes (e.g., sulfur–organic, broad range), while Ca, Mg, and Fe dissolution rates significantly correlated with richness and aftertaste-A, and Mo inversely correlated with sourness and saltiness. Contribution assessment showed that only Ca, K, Mg, and Se could be marginally supplemented, but the tea amounts needed far exceeded typical intake. In summary, element dissolution in Dahongpao tea is co-regulated by brew count and total content, with complex element–flavor interactions. Tea is not a primary mineral source; consumption should be individualized by age and physiological status. Full article

The plastisphere critically modulates interactions among microplastics (MPs), biofilms, and trace metals under environmentally realistic conditions, governing the interfacial reactivity of plastisphere-coated microplastics. Here, we investigated cobalt (Co) adsorption onto large polypropylene (PP) primary microplastics (~4 mm) exposed for 28 days in a flow-through riverine mesocosm across a gradient of Co concentrations (0–60 µg·L⁻¹). A multi-technique analytical approach was employed, combining inductively coupled plasma mass spectrometry (ICP-MS), laser ablation ICP-MS (LA-ICP-MS), quantitative PCR (qPCR), and scanning electron microscopy (SEM). Cobalt accumulation increased linearly with time, consistent with apparent first-order dependence on aqueous Co concentration under constant exposure, reaching 38 ± 3 mg·kg⁻¹ after 28 days at 60 µg·L⁻¹, with no saturation observed. The concentration-dependent Co accumulation was well described by an empirical power-law model (Q = KC₀ⁿ), with the empirical coefficient K increasing linearly over time, reflecting the progressive increase in Co accumulation at a given aqueous concentration. Microbial colonization developed rapidly on MPs, with 16S and 18S rRNA gene copy numbers stabilizing after 14 days, while surface-normalized Co signals increased sharply after day 21, indicating a time-dependent modification of biofilm properties influencing Co retention. SEM confirmed complex microbial structures, including diatom-like cells. No cobalt adsorption was observed under sterile conditions, confirming the key role of biofilm presence. These findings highlight the dynamic role of the plastisphere as a chemically and biologically active interface under environmentally realistic riverine conditions, with implications for contaminant fate, bioavailability, and risk assessment in freshwater systems affected by plastic pollution. Full article

Ti-35Nb-2Ta-3Zr (TNTZ) β-titanium alloy is attractive for biomedical applications because of its relatively low elastic modulus and composition based on nominally non-cytotoxic alloying elements; however, its surface hardness and intrinsic bioactivity remain limited. In this study, Zn nanoparticles were incorporated into the near-surface region of TNTZ by friction stir processing (FSP), followed by compression plasma flow (CPF) treatment in nitrogen. Cross-sectional scanning electron microscopy and energy-dispersive X-ray spectroscopy, X-ray diffraction, microhardness testing, and inductively coupled plasma mass spectrometry after 60 days of immersion in simulated body fluid were used to characterize the modified layers. CPF treatment produced a distinct surface-modified layer approximately 10–15 μm thick, increased the Zn signal within the upper approximately 11 μm, and generated diffraction peaks assigned to Ti₂N. The fitted β-phase lattice parameter decreased with nominal X-ray penetration depth, and tensile residual stresses were calculated for all CPF-treated conditions. Sample 1 exhibited the highest microhardness at the lowest applied load. After 60 days of immersion, the mean Zn concentration was 261.87 ± 0.0031 μg/L for FSP and 102.41 ± 0.0063 μg/L for FSP + CPF, corresponding to an approximately 60.9% lower mean cumulative Zn concentration after CPF treatment. Electrochemical, tribological, and biological testing is still required to establish corrosion, wear, and biological performance. Full article

Eastern Croatia includes settlements with historically elevated arsenic (As) concentrations in drinking water. Of 488 recruited adults, nine were excluded solely because no questionnaire was available; the exclusion was independent of measured arsenic concentrations, and the harmonised analytical cohort therefore comprised 479 adults from eight settlements. Total As concentrations in drinking water, hair, serum, and urine were measured in samples collected in June 2015 by inductively coupled plasma mass spectrometry. Kidney cancer data (ICD-10 C64) for 2000–2018 were obtained from the Croatian National Cancer Registry and analysed ecologically. MDCK1 cells were exposed to As₂O₃ at 10–200 µg/L for 48, 72, and 96 h, and acetylcholinesterase (AChE) activity was measured in human erythrocytes. Čepin had the highest median As concentrations in drinking water (191.75 µg/L) and urine (68.14 µg/L). Across all eight settlements, drinking-water As was strongly associated with urinary As (slope = 0.537; 95% CI, 0.352–0.722; R² = 0.894; p < 0.001). However, in a sensitivity analysis excluding Čepin and using the seven non-Čepin settlement means reported, the association weakened (r = 0.740; R² = 0.548; slope = 1.246; 95% CI, −0.054 to 2.547; p = 0.057), indicating substantial influence of the Čepin hotspot. Associations with hair As (R² = 0.294; p = 0.165) and serum As (R² = 0.239; p = 0.219) were not statistically significant. In a multivariable Gamma generalized linear model, residence in Čepin was associated with higher expected urinary As than residence in Vladislavci (adjusted mean ratio, 2.90; 95% CI, 1.90–4.42; p < 0.001), while female sex was associated with a lower expected concentration (adjusted mean ratio, 0.80; 95% CI, 0.66–0.97; p = 0.024). No statistically significant effect of As₂O₃ on MDCK1 viability or erythrocyte AChE activity was observed. The findings support urinary total As as a biomarker of recent environmental exposure, but do not establish causal associations with kidney toxicity or kidney cancer. Full article

This study investigates how lithological origin influences the engineering performance, stripping resistance, and multi-scale material characteristics of aggregates used in asphalt pavement applications. Three representative aggregate systems—carbonate limestone from Cebeci (Istanbul), siliciclastic sandstone from Arnavutköy (Istanbul), and mafic volcanic basalt from the Karatepe Formation (Çorlu, Tekirdağ)—were comparatively evaluated. The experimental program included physical and mechanical tests, X-ray diffraction, inductively coupled plasma optical emission spectroscopy, inductively coupled plasma mass spectrometry, thin-section petrography, and stripping resistance testing. Physical, mechanical, and durability test results were evaluated using replicate measurements and are reported as mean ± standard deviation where applicable. Basalt showed the best mechanical and durability performance, with the lowest flakiness index, Los Angeles abrasion value, and magnesium sulfate soundness loss, but exhibited the lowest unmodified retained coating. Limestone showed a higher inferred binder-affinity potential, interpreted from its calcite-dominated mineralogy, whereas sandstone displayed higher sensitivity related to particle shape, mineralogical heterogeneity, phyllosilicate-bearing components, and petrographic pore/microvoid characteristics. The addition of 0.5% CL 90 S hydrated lime produced an intermediate improvement in stripping resistance, increasing retained coating values to 75–80% for all aggregates, whereas 1.0% hydrated lime further improved retained coating to 80–85%. Higher lime contents of 1.5% and 2.0% did not provide additional improvement under the applied laboratory conditions. These results indicate that 1.0% CL 90 S hydrated lime represents the most effective dosage among the tested conditions. Overall, the results demonstrate that aggregate performance is governed by coupled lithological controls involving mineralogy, petrography, geochemistry, inferred surface-related interaction potential, mechanical durability, stripping resistance, and anti-stripping additive response. The proposed framework should therefore be interpreted as a comparative multi-scale assessment rather than a direct predictive model. Full article

The Dilaqiu pegmatite-type rare-metal deposit lies in the southeastern part of the Ke’eryin orefield, within the Central Songpan–Ganzi orogenic belt. It is a large, recently discovered lithium-dominated deposit with associated tin, niobium, and tantalum resources. Detailed petrographic observations were combined with electron probe microanalysis (EPMA), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) trace element analysis and U−Pb dating of cassiterite from albite–spodumene pegmatite. The mineralogical, EPMA major element, and LA-ICP-MS trace element data indicate that cassiterite is genetically linked to the rare-metal pegmatite rather than to a later hydrothermal event. Cassiterite U−Pb dating yielded an age of 194.8 ± 1.2 Ma (n = 28, MSWD = 0.94), which is interpreted to indicate Early Jurassic mineralization associated with early Yanshanian magmatism. Comparison with rare-metal deposits elsewhere in the Songpan–Ganzi orogenic belt further indicates broadly similar metallogenic ages and mineralization types and a shared post-orogenic extensional setting. Full article

Human biomonitoring in environmentally complex regions requires not only matrices that are easy to collect but also careful consideration of external contamination, non-detects, and analytical uncertainty. Inductively coupled plasma mass spectrometry (ICP–MS) was used to measure the concentrations of 24 elements in occipital scalp-hair samples from 134 adults living in Campania, southern Italy (67 women and 67 men; age range: 20–72 yr). Continuous models were restricted to elements detected in at least 70% of adults and were fitted using HC3 heteroskedasticity-consistent standard errors, with Benjamini–Hochberg correction for the false discovery rate (FDR). Ca, Zn, Mg, K and Cu were the most abundant elements in the hair profile. The most consistent adjusted association was lower concentrations of Ca, Mg, Cu, Cr and Zn in men. Pb showed a strongly right-skewed distribution, whereas Cd was detected in only 22.4% of adults; this low detection frequency did not support a population-level elevation claim. Spatial summaries and clustering were retained for exploratory purposes: Kruskal–Wallis tests indicated a zone-level difference only for Zn, whereas patterns in Pb, Cr, As, Cd, and V were interpreted as priorities for confirmatory sampling rather than as evidence of territorial risk. Sensitivity analyses based on the limit of detection (LOD) supported retaining As and Cd as descriptive outcomes; V associations were not promoted to primary findings because the V detection frequency was below the pre-specified threshold. These findings support the use of hair biomonitoring as a non-invasive screening approach in mixed geogenic–anthropogenic settings, provided that sex, sample mass, non-detects, outliers, and external contamination are considered explicitly and that confirmatory matrices are used where appropriate. Full article

Iron beneficiation tailings from the Bayan Obo West Mine constitute a low-grade secondary rare-earth resource in which rare-earth minerals are finely disseminated and intricately intergrown with gangue. This study quantified the modes of occurrence of rare-earth minerals and assessed an integrated flowsheet comprising screening, magnetic separation, and flotation. The feed contained 1.32 wt.% rare-earth oxides (REOs), as determined by X-ray fluorescence spectrometry (XRF) and inductively coupled plasma optical emission spectrometry (ICP-OES). X-ray diffraction (XRD), scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), and automated mineralogy (AMICS) further showed that monazite and bastnäsite hosted 47.39% and 39.19% of the total REOs, respectively. Screening at 74 μm rejected 32.60% of the feed as a coarse fraction containing 0.65 wt.% REOs. Subsequent wet high-intensity magnetic separation reduced the mass entering flotation to 54.35% of the original feed while retaining 74.94% of the feed REOs and increasing the REO grade to 1.82 wt.%. Closed-circuit flotation with one rougher and three cleaner stages yielded a concentrate containing 51.99 wt.% REOs at an overall recovery of 52.38%. Rare-earth minerals accounted for 82.55 wt.% of the concentrate, including 41.65 wt.% monazite and 33.96 wt.% bastnäsite. This study thus demonstrated the feasibility of producing a high-grade rare-earth concentrate from the low-grade, fine-grained iron beneficiation tailings of the Bayan Obo West Mine characterized by complex mineral intergrowths, providing a practical basis for further rare-earth beneficiation and flowsheet optimization. Full article

Inappropriate concentrations of elements in formulae for infants may lead to adverse health effects. Selenium (Se) is a trace element essential for the proper development of infants. It is naturally present in human milk and is also added to infant formulae. However, both insufficient and excessive Se intake may be harmful. The aim of this study was to determine Se concentrations and chemical forms in 148 formulae for infants available on the Polish market and to assess their nutritional safety. Se concentrations were determined using inductively coupled plasma mass spectrometry (ICP-iCRC-MS). Se speciation was performed using a HPLC system coupled to ICP-iCRC-MS. The Se concentrations in most analyzed formulae were in good agreement with the recommended EU limits (median 4.5 µg/100 kcal, range 0–15.6 µg/100 kcal). However, the estimated daily intake for 6-month-old infants exceeded the tolerable upper intake level in six formulae, indicating a potential health risk. Speciation analysis showed that the dominant Se forms were sodium selenite and sodium selenate, and their levels were mostly consistent with the manufacturers’ declarations. Additionally, trace amounts of selenometionine (SeMet) and methyloselenocysteine (MeSeCys) were detected. Therefore, regular monitoring of the composition of infant formulae remains necessary. The detection of SeMet and MeSeCys provides new avenues for research on Se content and Se speciation in formulae intended for infants. Full article

Cadmium (Cd), a widespread pollutant, is primarily absorbed via diet and smoking. Chronic Cd exposure has been associated with various adverse health effects, including renal tubular and skeletal damage. Urinary Cd concentration accurately reflects cumulative Cd exposure owing to its strong correlation with renal cortical Cd levels. This study evaluated the accuracy of estimated lifetime Cd intake by examining its correlation with urinary Cd levels after soil remediation, an aspect unreported even in the Kakehashi River Basin. A total of 565 men and 450 women were included. Lifetime Cd intake (g) was estimated using an established exposure assessment model that incorporated individual residential history, rice Cd concentrations, and dietary assumptions. Urinary Cd concentrations were determined using inductively coupled plasma mass spectrometry. Linear regression analyses were conducted between lifetime cadmium intake and urinary cadmium concentration. The obtained standardized regression coefficients were 0.49 for men and 0.54 for women (both p < 0.001), indicating strong associations. Despite possible exposure misclassification, these findings support the utility of lifetime cadmium intake as a useful surrogate indicator of cumulative cadmium exposure and provide further evidence for its application in risk assessment and the derivation of tolerable cadmium intake values. Full article

Coffee is deeply embedded in Saudi culture and is among the most consumed beverages worldwide. However, contamination by toxic heavy metals may represent an underrecognized public health concern, particularly in regions already burdened by diabetes mellitus and cardiovascular disease. This study evaluated concentrations of lead (Pb), cadmium (Cd), arsenic (As), chromium (Cr), and nickel (Ni) in 21 commercial coffee samples representing seven product categories marketed in Saudi Arabia. Samples were prepared using EPA Method 3050B acid digestion and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Health risks were assessed through estimated daily intake (EDI), hazard quotient (HQ), hazard index (HI), and incremental lifetime cancer risk (ILCR) using USEPA exposure parameters and Saudi-specific coffee consumption data. All metals were detected in every sample. Mean concentrations (mg/kg dry weight) were 1.638 for Pb, 0.560 for Cd, 0.622 for Cr, 0.536 for Ni, and 0.034 for As. Cadmium exceeded the European Union maximum limit for roasted coffee in all samples, while elevated Pb levels were observed in dark roast and Yemeni coffees. Although the overall non-carcinogenic risk remained below the accepted threshold (HI = 0.438), the combined ILCR for As, Cd, and Pb was 5.84 × 10⁻⁵. Inclusion of a conservative screening-level chromium contribution, calculated by assuming that all measured total Cr was present as Cr(VI), increased the upper-bound total ILCR to 9.38 × 10⁻⁵. This value remained within, but approached the upper boundary of, the risk-management range applied in this study. These findings highlight the need for strengthened monitoring and regulatory control of coffee products in Saudi Arabia. Full article

Nanomaterials have been extensively incorporated and are commonly used in everyday life. Rising human exposure to risks has highlighted the carcinogenic hazards from prolonged exposure, prompting the development of “Nanogenotoxicology” as a distinct academic field. However, conventional in vitro micronucleus assay systems cannot ensure adequate contact between nanomaterials and cellular genetic material, which prevents an accurate assessment of the clastogenic risk posed by nanomaterials. In this study, the p53-competent human cell line TK6 and the karyotypically stable conventional cell line CHL were used to conduct a cytokinesis-block micronucleus assay (CBMN), and the cytoskeleton inhibitor cytochalasin B was added to the culture system after nanomaterial exposure. Ag40 (40 nm silver nanoparticles) and polystyrene microspheres were employed as the nanoscale positive and negative controls, respectively. Prior to this study, hyperspectral imaging and inductively coupled plasma mass spectrometry were used to verify that the cellular association of Ag40 was not markedly affected by the addition of rat liver S9 mixture and cytochalasin B. Our results showed that, under exposure periods of 4 h (with or without rat liver S9 mixture), 24 h, 48 h and 72 h, Ag40 at concentrations ranging from 5 to 40 µg/mL significantly increased the micronucleus frequency up to 6%, while polystyrene microspheres showed negative results. Therefore, Ag40 and polystyrene microspheres were identified as the respective nanoscale positive and negative controls for CBMN. The established method was further validated in two independent laboratories using a nano-silver burn wound dressing, and both chemical and nanoscale controls were included. The methodology developed in the present study provided a foundational basis for the development of the standard YY/T 1897-2023 in China. Full article

Elevated potentially toxic element (PTE) contents in soils can pose important environmental concerns, particularly in regions where natural metal enrichment associated with ultramafic and mineralized geological settings overlaps with potential anthropogenic inputs. This study evaluates the distribution, enrichment, and probable controls of As, Ni, Co, Cu, Cr, Pb, and Zn in 35 geo-referenced soil samples from the Ortaklar region, Türkiye, with the aim of providing a geochemical basis for environmental monitoring and sustainable land management. PTE contents were determined by ICP-MS (inductively coupled plasma mass spectrometry), and their degree of enrichment was evaluated using the geo-accumulation index (I_geo), contamination factor (CF), and pollution load index (PLI), supported by correlation analysis and multivariate statistical approaches. Mean contents decreased in the order Ni (1972 mg kg⁻¹) > Cr (924 mg kg⁻¹) > Cu (290 mg kg⁻¹) > Zn (188 mg kg⁻¹) > Co (122 mg kg⁻¹) > As (15.9 mg kg⁻¹) > Pb (6.8 mg kg⁻¹). Ni exhibited the highest degree of enrichment and was the dominant contributor to the overall PTE load, while Cr, Cu, and Co also showed substantial enrichment. Mean I_geo values indicated moderate to heavy enrichment for Ni (2.65) and As (2.36), and moderate enrichment for Cr (1.45) and Co (1.02). The mean PLI value of 6.99 indicates a substantial cumulative enrichment of PTEs relative to the adopted reference values. Strong associations among Ni, Cr, and Co are consistent with a dominant geogenic contribution from ultramafic/serpentinitic parent materials and their weathering products, whereas the distributions of As, Cu, and Zn suggest more complex controls involving lithology, mineralization, and potentially localized agricultural or other anthropogenic inputs. However, these statistical relationships indicate probable controls rather than definitively establishing elemental sources. The elevated total PTE contents and contamination indices identify the Ortaklar soils as requiring continued geochemical monitoring; nevertheless, they do not constitute direct evidence of human-health risk because metal speciation, mobility, bioavailability, and exposure pathways were not investigated. The findings provide a regional geochemical framework for distinguishing natural PTE enrichment from anthropogenic influences and for guiding future mineralogical, bioavailability, and spatial investigations in ultramafic and mineralized soil environments. Full article

Afghanistan’s Panjshir Valley is an important emerald-producing region in Asia. In this study, emeralds from Kamar Safid in Southeastern Panjshir were investigated by Fourier-transform infrared (FTIR), Raman spectroscopy, ultraviolet–visible–near-infrared (UV-Vis-NIR) spectroscopy, and laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS). These Kamar Safid emeralds are generally small, light-green-to-green crystals. Microscopic observations revealed abundant acicular and tubular three- or two-phase fluid inclusions, with transparent feldspar-group mineral inclusions. Solid phases in the fluid inclusions commonly consist of carbonate crystals or several transparent halite daughter crystals. FTIR spectra of samples indicated that the absorption of type II H₂O was higher than type I H₂O in the emeralds from Kamar Safid. The UV-Vis-NIR spectra are characterized by Cr- and V-related absorption bands, which are stronger than Fe-related absorptions. LA-ICP-MS results indicate slightly higher V contents and lower Cr contents than emeralds from other Panjshir mining areas. The relatively low total Cr and V contents of Kamar Safid emeralds account for the overall lighter color, suggesting that Cr and V are the principal chromophores, whereas Fe secondarily modifies hue. Rb, Cs, and Sc contents are 6.2–24.3 ppm, 11.9–141.6 ppm, and 92–1461 ppm, with total alkali contents of 4903.10–14,257.18 ppm. Cs-Rb, Cs-Sc, Li-Cs, and Li-Sc binary logarithmic diagrams indicate enrichment in Sc and Rb and depletion in Li and Cs. Full article