Metal Exposure Assessment Research Articles

Metals accumulation affects bone and muscle in osteoporotic patients: A pilot study

Osteoporosis is the most common bone disease, characterized by decreased bone mineral density (BMD) and often associated to decreased muscle mass and function. Metal exposure plays a role in the pathophysiology of osteoporosis and affects also muscle quality. The aim of this study was to assess the association between metal levels in bone and muscle samples and the degeneration of these tissues. A total of 58 subjects (30 male and 28 female) was enrolled and classified in osteoporotic (OP, n = 8), osteopenic (Ope, n = 30) and healthy (CTR, n = 20) subjects, according to BMD measures. Femoral head bone samples and vastus lateralis muscle samples were collected during hip arthroplasty surgeries. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis showed increased levels of Al, Cd and Pb in OP and Ope bone tissue compared to CTR subjects (p = 0.04, p = 0.005 and p = 0.01, respectively). Whereas, increased levels of Co, Cd and Pb were measured in OP and Ope muscle tissues, compared to CTRs (p < 0.001, p = 0.02 and p = 0.01, respectively). In addition, Al, Cd and Pb levels in bone and Cd and Co levels in muscle were negatively correlated with BMD. A negative association among Co, Cd, Cr and Hg levels and muscle fibers diameter was also observed in muscle tissues. This study assessed that metal exposure can affects bone and muscle tissue quality and may contribute to the onset and progression of musculoskeletal diseases such as osteoporosis. Therefore, it is important to implement metal exposure assessment and their impact on disease development, in order to manage and prevent metal accumulation effects on bone and muscle quality.

Whey Protein Dietary Supplements: Metal Exposure Assessment and Risk Characterization.

Protein supplements (PS) are trendy foods, especially those made from whey. In addition to providing protein, these products are a source of metals, providing essential elements (Na, K, Mg, Ca, Mo, Mn, Fe, Co, Cu, and Zn) and other potentially toxic elements (Al, B, Sr, V Ba, and Ni). In this study, 47 whey PS samples were analyzed for mineral elements by ICP-OES, and their dietary exposures were assessed for three consumption scenarios. Elements found in higher concentrations were K (4689.10 mg/kg) and Ca (3811.27 mg/kg). The intake of 30 g PS (average recommended amount/day) provides about 20% of the established reference value (NRI) for Cr (18.30% for men and 25.63% for women) and Mo (26.99%). In a high daily consumption scenario (100 g PS/day) and when the maximum concentrations are considered, Cr, Zn, Fe, Mo, and Mg dietary intakes of these metals exceed the daily recommended intakes and could pose a risk. The daily intake of 30, 60, and 100 g of whey PS for 25 years does not pose a health risk since the hazard index (HI) is less than one in these consumption scenarios, and the essential elements contributing most to HI are Co, followed by Mo and Cr. It is recommended to improve the information to the consumers of these new products. Furthermore, to help in the management and prevention of these potential health risks, it would be advisable to improve the regulation of these dietary supplements and their labeling.

Reliability of low mass toenail samples as biomarkers of chronic metal exposure.

Toenails are a promising matrix for chronic metal exposure assessment, but there are currently no standard methods for collection and analysis. Questions remain about sample mass requirements and the extent to which metals measured in this matrix are representative of chronic body burden. This study proposes a method to maximize sample conservation for toenail metals analysis using inductively coupled plasma mass spectrometry (ICP-MS). We demonstrate the reliability of an ~25 mg toenail sample (typically 1-2 clippings) for metals analysis and evaluate the intra-individual variability of multiple metals in this matrix over time in men from the Gulf Long-term Follow-up (GuLF) Study. Toenail samples from 123 GuLF Study participants were collected at two visits 3 years apart and analyzed for 18 elements using ICP-MS. Participants with samples exceeding 200 mg at the first visit (n = 29) were selected for triplicate sub-sample analysis. Kendall's coefficient of concordance (W) was used to assess sub-sample reliability and Spearman's correlation coefficients (ρ) were used to evaluate fluctuations in elemental concentrations over time. Results were not reported for Cd, Co, Mo, Sb, and V (detected in <60% of the samples). There was strong agreement among triplicate samples (Kendall's W: 0.72 (Cu)-0.90 (Cu)) across all elements evaluated, moderate correlations of elemental concentrations (Spearman's ρ: 0.21-0.42) over 3 years for As, Ca, Cr, Fe, Pb, Mn, and Zn, and strong correlations (>0.50) for Se, Cu, and Hg. This toenail reliability study found that a low-mass (~25 mg) toenail sample (1-2 clippings) is suitable for the determination of most elements using ICP-MS and helps to increase the analytical capacity of limited toenail biospecimens collected in cohort studies. The results highlight differences in the suitability of toenails for chronic metal exposure assessment by element and underscore the need to consider intra-person variability, especially when comparing results across studies. We also provide recommendations for analytical standardization and the partitioning of the total collected toenail sample into multiple analytic sub-samples for future studies using toenail biospecimen for multiple assays.

Assessment of metal exposure (uranium and copper) in fatty acids and carbohydrate profiles of Calamoceras marsupus larvae (Trichoptera) and Alnus glutinosa leaf litter.

Physiological changes were explored in fatty acids (FA) and carbohydrate (CHO) composition in the shredder Calamoceras marsupus larvae (Trichoptera) and leaf litter (C. marsupus food) exposed to copper and uranium under natural and experimental conditions. We measured FA and CHO content in leaf litter and larvae specimens from reference and impacted streams, and exposed for 5 weeks to four realistic environmental concentrations of copper (35 μg L-1 and 70 μg L-1) and uranium (25 μg L-1 and 50 μg L-1). Regarding FA, (1) leaf litter had a reduced polyunsaturated FA (PUFA) content in metal treatments, s (14 to 33% of total FA), compared to natural conditions (≥39% of total FA). Leaf litter exposed to uranium also differed in saturated FA (SFA) composition, with lower values in natural conditions and higher values under low uranium concentrations. (2) C. marsupus had/showed low PUFA content under Cu and U exposure, particularly in high uranium concentrations. Detritivores also decreased in PUFA under exposure to both metals, particularly in high uranium concentrations. On the other hand, (1) microorganisms of the biofilm colonizing leaf litter differed in CHO composition between natural (impacted and reference) and experimental conditions, with glucose and galactose being consistently the most abundant sugars, found in different amounts under copper or uranium exposure; (2) CHO of detritivores showed similar high galactose and fucose concentrations in contaminated streams and high copper treatments, whereas low copper treatment showed distinct CHO profiles, with higher mannose, glucose, arabinose, and fucose concentrations. Our study provides evidence of metal exposure effects on FA and CHO contents at different trophic levels, which might alter the quality of food flow in trophic webs.

Efficiency of metal bioaccumulation in acanthocephalans, gammarids and fish in relation to metal exposure conditions in a karst freshwater ecosystem

BackgroundEach of the bioindicator organisms studied, such as fish, crustaceans, or parasites, have certain advantages when used in the assessment of metal exposure. In this research, special attention was given to intestinal parasites, acanthocephalans, as effective metal bioaccumulators with the main aim of estimating and comparing metal accumulation in all organisms involved in their life cycle and testing their usage as sensitive bioindicators in metal exposure assessments. MethodsEfficiency of metal accumulation was evaluated in fish intestine (brown trout, Salmo trutta Linnaeus, 1758), gammarids (Gammarus balcanicus Schäferna, 1922) and acanthocephalans (Dentitruncus truttae Sinzar, 1955) in the Krka River at site threatened by industrial and municipal wastewaters (Town of Knin) and reference site (Krka River source) in two seasons (autumn and spring). All samples were digested in a drying oven at 85 °C for 3.5 h using nitric acid and hydrogen peroxide. Samples were diluted with ultrapure water and total concentrations of 15 trace and macroelements were measured by HR ICP-MS. ResultsHigher concentrations of Co, Cu, Fe and Mn at the contaminated than at the reference site were recorded in all bioindicator organisms. Additionally, Se, Sr, Zn, Ca, K and Mg were elevated at the contaminated site in acanthocephalans, Cs, Pb, Zn and K in gammarids and Se, Sr and Ca in fish intestine. Opposite, concentrations of Cd, Cs and Rb were mostly higher in organisms from the reference than wastewater impacted site, which did not coincide with waterborne metal exposure but indicated importance of assessing dietary metal uptake. ConclusionMore effective metal accumulation was confirmed in acanthocephalans than fish and gammarids, especially of Cd and Pb in respect to gammarids, and of Cd, Cu, Pb, Mn and Sr in respect to fish intestine. Thus, both fish intestine and whole body of D. truttae were confirmed as sensitive indicators of low environmental metal exposure, reflecting site-specific differences, which proved their potential to be used in monitoring programmes and metal exposure assessment in real environmental situations.

Variability, Clearance, and Concentration of Multiple Metals and Risk of Kidney Function Abnormality: A New Integrative Metal Exposure Assessment Approach

Variability, Clearance, and Concentration of Multiple Metals and Risk of Kidney Function Abnormality: A New Integrative Metal Exposure Assessment Approach

Exploring a new method for the assessment of metal exposure by analysis of exhaled breath of welders

PurposeAir monitoring has been the accepted exposure assessment of toxic metals from, e.g., welding, but a method characterizing the actual dose delivered to the lungs would be preferable. Sampling of particles in exhaled breath can be used for the biomonitoring of both endogenous biomarkers and markers of exposure. We have explored a new method for the sampling of metals in exhaled breath from the small airways in a study on welders.MethodsOur method for particle sampling, Particles in Exhaled Air (PExA®), is based on particle counting and inertial impaction. We applied it on 19 stainless steel welders before and after a workday. In parallel, air monitoring of chromium, manganese and nickel was performed as well as blood sampling after work.ResultsDespite substantial exposure to welding fumes, we were unable to show any significant change in the metal content of exhaled particles after, compared with before, exposure. However, the significance might be obscured by a substantial analytical background noise, due to metal background in the sampling media and possible contamination during sampling, as an increase in the median metal contents were indicated.ConclusionsIf efforts to reduce background and contamination are successful, the PExA® method could be an important tool in the investigations of metals in exhaled breath, as the method collects particles from the small airways in contrast to other methods. In this paper, we discuss the discrepancy between our findings and results from studies, using the exhaled breath condensate (EBC) methodology.

Urban mosquitoes and filamentous green algae: their biomonitoring role in heavy metal pollution in open drainage channels in Nairobi industrial area, Kenya

BackgroundIndustrial wastewater is a human health hazard upon exposure. Aquatic organisms in contaminated wastewater may accumulate the toxic elements with time. Human population living in informal settlements in Nairobi industrial area risk exposure to such toxic elements. Biomonitoring using aquatic organisms in open drainage channels can be key in metal exposure assessment. Levels of Mercury (Hg), Lead (Pb), Chromium (Cr), Cadmium (Cd), Thallium (Tl), and Nickel (Ni) were established in samples of wastewater, filamentous green algae (Spirogyra) and mosquitoes obtained from open drainage channels in Nairobi industrial area, Kenya.ResultsPb, Cr, & Ni levels ranged from 3.08 to 15.31 µg/l while Tl, Hg, & Cd ranged from 0.05 to 0.12 µg/l in wastewater. The Pb, Cr, Ni, & Cd levels were above WHO, Kenya & US EPA limits for wastewater but Hg was not. Pb, Cr, Tl, & Ni levels in assorted field mosquitoes were 1.3–2.4 times higher than in assorted laboratory-reared mosquitoes. Hg & Cd concentrations in laboratory-reared mosquitoes (0.26 mg/kg & 1.8 mg/kg respectively) were higher than in field mosquitoes (0.048 mg/kg & 0.12 mg/kg respectively). The levels of Pb, Cr, & Ni were distinctively higher in field mosquito samples than in wastewater samples from the same site. Pb, Cr, Ni, Cd & Hg levels in green filamentous Spirogyra algae were 110.62, 29.75, 14.45, 0.44, & 0.057 mg/kg respectively. Correlation for Pb & Hg (r (2) = 0.957; P < 0.05); Cd & Cr (r (2) = 0.985; P < 0.05) in algae samples was noted. The metal concentrations in the samples analyzed were highest in filamentous green algae and least in wastewater.ConclusionWastewater, mosquitoes, and filamentous green algae from open drainage channels and immediate vicinity, in Nairobi industrial area (Kenya) contained Hg, Pb, Cr, Cd, Tl, and Ni. Mosquitoes in urban areas and filamentous green algae in open drainage channels can play a role of metal biomonitoring in wastewater. The potential of urban mosquitoes transferring heavy metals to human population from the contaminated wastewater should be investigated.

Quantitative skin exposure assessment of metals: A case study

This article provides guidance into the quantitative risk assessment of skin exposures to metals. The use of wipe sampling methodologies has been shown to be standardised and effective for skin exposure assessment to metals. However, there is a lack of guidance documents and frameworks available to evaluate the level of health risk to workers from skin exposures to metals. Adverse health effects from exposures to metals have been described in the literature (Fernández-Nieto et al. 2006; Herman et al. 2006; Kreiss et al. 1996). Monitoring of workplace exposures typically focuses on the assessment of respiratory exposures. To provide a safe workplace there is a need to ensure all routes of exposure are risk assessed and controlled. The goal of this article was to develop skin (surface) exposure limits to metals, using the construction industry as a test environment, to quantitatively assess worker health risk of skin exposures to metals. This research concluded it was not feasible to establish single quantitative skin exposure limits to metals due to the many assumptions surrounding dermal exposures. A range of acceptable exposure limits are presented.

Exposure assessment of treated greywater reused for irrigation

Abstract The aim of the study was to assess the risk of exposure of treated greywater reused for irrigation. It consisted of untreated and treated greywater quality analysis and heavy metal exposure assessment. After treatment with a local conventional stabilization pond, parameters such as BOD, COD, Zn, and Pb dropped to 35.63, 9.95, 0.011, and 0.001 mg/L, respectively. Total coliform and fecal coliform decreased to 23,417 and 5,666 MPN/100 mL, respectively. These results showed almost all detected contaminants in treated greywater were minimized and did not exceed Thailand's standard and World Health Organization guidelines. After that, treated greywater was reused for irrigation. There were three vegetable plots: treated greywater, tap water with fertilizer, and tap water. There were seven edible plants, four leafy and three fruiting vegetables, cultivated in each plot. Zn, Pb, Cd, Cu, and Hg were detected depending on the kind of plant; for example, the maximum concentration was found in leafy vegetables. However, the concentrations of contaminants did not exceed the Codex standard for contaminants and toxins in foods and Thailand's standard. Risk characterization showed no risk with a hazard quotient far less than 1. Therefore, treated greywater reuse could be considered to promote sustainable water management in the community.

Intestine of invasive fish Prussian carp as a target organ in metal exposure assessment of the wastewater impacted freshwater ecosystem

The application of invasive fish Prussian carp (Carassius gibelio Bloch, 1782) as bioindicator organism, using intestine as bioindicator tissue of anthropogenic influence in the lowland Ilova River was estimated. Intestinal tissue enables the investigation of dietborne metal uptake, so the first record on intestinal metal levels in Prussian carp was presented, as total and cytosolic fraction, which indicates the proportions of potentially toxic and bioavailable metals. Pollution impact was also estimated by analyses of biomarkers of oxidative stress (malondialdehyde), antioxidative capacity (catalase and glutathione) and of metal exposure (metallothioneins). All analyzed parameters were compared in the intestine of fish from the reference site and contaminated site impacted by technological and municipal wastewaters in two seasons. Both total and cytosolic As, Ca, Cd, Cs, Cu, Mg, Na and Rb levels were significantly higher at contaminated than the reference site in at least one season, whereas Mn and V had higher concentrations at the reference site. Despite differences in concentrations, average proportions of total metal levels in cytosolic fraction were comparable at two sites, i.e. over 70% for Na, K, Rb, Se, Cd, Cs, As and Mo, indicating their high possibility of binding to important biomolecules. In addition, higher levels of malondialdehyde in both seasons and enhanced catalase activity in spring, indicated disturbed environmental conditions near the contaminated site and need of continuous monitoring of this region. Finally, our research represents successful application of widely distributed invasive species in ecotoxicological studies, whereas intestine was shown as a suitable bioindicator tissue, clearly reflecting dietary metal uptake.

Quantitative skin exposure assessment of metals: a systematic literature review of current approaches for risk assessment using the construction industry as an exposure scenario.

This article summarises a systematic literature review of skin exposure assessment methods and concepts for deriving skin (dermal) exposure limits for metals, using the construction industry, where there is a high prevalence of occupational skin exposures as a test environment. A systematic literature review was undertaken across ten databases key to Occupational Health and Safety. Articles were considered for inclusion if they evaluated skin or surface exposure to metals or discussed the feasibility of establishing skin or surface exposure limits in an occupational setting. Only full text, peer-reviewed articles were retrieved. All publications up to 30/06/2019 were considered. The quality of evidence was evaluated based on methodology. A total of 71 studies were selected for inclusion in the review with 49 on skin exposure assessment methods for metals and 22 relating to the derivation of skin exposure limits. The use of wipe sampling methodologies was shown to be standardised and effective for sampling skin exposures to metals. In contrast, there was no scientific consensus on the concept of quantitative skin exposure limits. There was greater strength of evidence that wipe methods for the measurement of metals would work well. A research gap with respect to the development of health-based skin exposure limits for metals was identified. Frameworks currently proposed for devising quantitative skin exposure limits are provided. These approaches could be adapted to improve the risk assessment of skin exposures to surface metal contaminants.

Health Risks Assessment of Metal Exposure from a Tropical Semi-urban Soil

ABSTRACTThe concentrations of metals (Cr, Pb, Zn) in the suburban soil of Jengka, Malaysia and their potential risks to human health have been determined. This study estimated both carcinogenic and non-carcinogenic risks using the hazard index (HI) and lifetime cancer risk (LCR). The mean concentrations of metal were dominated by Zn (85.91 mg/kg), followed by Pb (38.50 mg/kg) and Cr (26.24 mg/kg). The enrichment factor (EF) and geo-accumulation index (Igeo) suggested the enrichment of Cr, despite its lowest mean concentration. The HI values of metal for non-carcinogenic risks were in the order of Cr>Pb>Zn. For cancer risk, the LCR values for Cr of Jengka semi-urban soil were slightly higher (6.16E-4) than the acceptable LCR limits (1E-5). Dermal contact was the main route for both cancer and non-cancer risks. Cement work from construction sites and road dust were found to be having high metal exposure in corresponding to health risk assessments, particularly for sampling point adjacent to the entrance of residential construction areas. Therefore, preventive actions are necessary to minimize the health risks in the long term, especially for construction areas.

Dynamics of Lead Bioavailability and Speciation in Indoor Dust and X-ray Spectroscopic Investigation of the Link between Ingestion and Inhalation Pathways.

Lead (Pb) exposure from household dust is a major childhood health concern because of its adverse impact on cognitive development. This study investigated the absorption kinetics of Pb from indoor dust following a single dose instillation into C57BL/6 mice. Blood Pb concentration (PbB) was assessed over 24 h, and the dynamics of particles in the lung and gastro-intestinal (GI) tract were visualized using X-ray fluorescence (XRF) microscopy. The influence of mineralogy on Pb absorption and particle retention was investigated using X-ray absorption near-edge structure spectroscopy. A rapid rise in PbB was observed between 0.25 and 4 h after instillation, peaking at 8 h and slowly declining during a period of 24 h. Following clearance from the lungs, Pb particles were detected in the stomach and small intestine at 4 and 8 h, respectively. Analysis of Pb mineralogy in the residual particles in tissues at 8 h showed that mineral-sorbed Pb and Pb-phosphates dominated the lung, while organic-bound Pb and galena were the main phases in the small intestines. This is the first study to visualize Pb dynamics in the lung and GI tract using XRF microscopy and link the inhalation and ingestion pathways for metal exposure assessment from dust.

Thallium accumulation in different organisms from karst and lowland rivers of Croatia under wastewater impact

Environmental contextDespite thallium’s high toxicity, water solubility and bioaccumulation tendency, its ecotoxicological relevance is largely unknown. We investigated thallium concentrations in fish, amphipods and parasitic worms from a karst freshwater ecosystem, and estimated total and cytosolic thallium concentrations in intestine of fish from the karst and lowland rivers impacted by wastewater inflow. The study provides the first data on dietary thallium accumulation in the intestine of freshwater fishes. AbstractThe aim of the present research was to investigate the bioaccumulation of thallium (Tl), a technology-critical element, in fish intestine and muscle, gammarids and the fish intestinal parasites, acanthocephalans, and to evaluate their potential as indicators of metal exposure in aquatic environments. Moreover, total and cytosolic (metabolically available and potentially toxic fraction) Tl concentrations were measured and compared between the intestines of brown trout (Salmo trutta Linnaeus, 1758) from the karst Krka River and Prussian carp (Carassius gibelio Bloch, 1782) from the lowland Ilova River. Since there is a scarcity of information on subcellular metal partitioning in the fish intestine, the results of Tl concentrations in acid digested intestinal tissue, homogenate and cytosol represent preliminary data on Tl diet-borne uptake in salmonid and cyprinid fish. In both rivers, samplings were performed upstream (reference site) and downstream (contaminated site) of the wastewater impact in autumn and spring. Total Tl concentrations were much higher in brown trout than Prussian carp, and higher proportions of cytosolic Tl concentrations were observed in the intestinal tissue of brown trout (45–71%) compared with that of Prussian carp (32–47%). Therefore, both indicators showed species- and site-specific differences. Considering different bioindicator organisms, the most effective Tl accumulation was evident in acanthocephalans compared with the fish tissues and gammarids, which confirmed the potential of fish parasites as bioindicators of metal exposure. Trends of spatial and temporal Tl variability were mostly comparable in all indicator organisms and for total and cytosolic Tl concentrations in the intestine of salmonid and cyprinid fish species, which confirmed their application as useful biological tools in metal exposure assessment.

A Dosimetry Study of Portable X-ray Fluorescence in Vivo Metal Measurements.

Portable x-ray fluorescence devices have grown in popularity for possible metal exposure assessment using in vivo measurements of bone and toenail. These measurements are accompanied by a small radiation dose, which is typically assessed by radiation safety committees to be minimal. However, an understanding of precise dose under different instrument conditions is still needed. This study set out to do a thorough investigation of the exact dose measurements using optically stimulated dosimeters, thermoluminescent dosimeters, and simulation with a Monte Carlo N-Particle transport code to assess the skin and total-body effective dose typical of portable x-ray fluorescence devices. We showed normal linear relationships between measurement time, x-ray tube current, and radiation dose with the device, and we showed a second order polynomial relationship with increasing voltage and radiation dose. Dose was quantified using thermoluminescent dosimeters, optically stimulated dosimeters, and simulations, which gave similar dose estimations. Skin dose for a standard 50-kV, 40-μA measurement for bone and toenail in vivo was 48.5 and 28.7 mSv, respectively, according to simulation results. Total-body effective dose was shown as 3.4 and 2.0 μSv for in vivo bone and toenail measurements, respectively, for adults using the portable x-ray fluorescence device.

Calibration and Validation of X-Ray Fluorescence Measurements for Non-Destructive Metal Exposure Assessment of Toenail Clippings from Nigeria

Calibration and Validation of X-Ray Fluorescence Measurements for Non-Destructive Metal Exposure Assessment of Toenail Clippings from Nigeria

Assessment of metal exposure (uranium and copper) by the response of a set of integrated biomarkers in a stream shredder

Environmental pollution with toxic trace metals is of great concern for the environment and for public health. Here we assess the response of the shredder caddisfly Calamoceras marsupus to sub-lethal exposures to copper and uranium. As endpoints we used growth, feeding and growth efficiency, and a set of enzyme biomarkers (oxidative stress: glutathione-S-transferase and catalase; respiration: lactate dehydrogenase; and the activities of acetylcholinesterase and Na+/K+-adenosine triphosphatase). We found that survival, growth, feeding and growth efficiency were not affected by any of the copper (0, 35 and 70μgL−1) or uranium (0, 25 and 50μgL−1) conditions. However, catalase activity increased with increased copper concentration, from 0.20 to 0.85nmolmin−1mg−1 protein (mean±SE; p<0.0001). Na+/K+ ATPase activity decreased with increased U concentration (from 0.16±0.01 to 0.11±0.01; mean±SE; p<0.001). The activities of LDH, GST and AChE enzymes did not differ across treatments. We concluded that CAT and Na+/K+-ATPase were the most sensitive biomarkers for copper and uranium respectively, at concentrations below levels that would affect growth and feeding.

Development, validation and testing of a skin sampling method for assessment of metal exposure.

Nickel, cobalt and chromium are frequent skin sensitizers. Skin exposure results in eczema in sensitized individuals, the risk being related to the skin dose. To develop a self-sampling method for quantification of skin exposure to metals, to validate the method, and to assess its feasibility. Defined metal doses (0.01-5 µg) were applied to the fingers of 5 participants. Skin areas (2 cm2 ) were sampled with 1% HNO3 , either as 0.1 ml on a swab, or as 0.5 ml on a wipe. Furthermore, 17 participants performed self-sampling by swab after 2 h of leisure activity. Samples were extracted in 1% HNO3 and analysed by inductively coupled plasma mass spectrometry. The sampling efficiency by swab was 46%, as compared with 93% for acid wipe sampling, for all tested doses. Most metal from the skin dose was detected in the first swab (33-43%). Despite lower sampling efficiency by swab, skin doses of metals following 2 h of leisure activity without hand washing were quantified in all participants, and ranged from 0.0016 to 0.15 µg/cm2 , from 0.00014 to -0.0020 µg/cm2 and from 0.00048 to -0.027 µg/cm2 for nickel, cobalt, and chromium, respectively. The results indicate a future potential of skin sampling by swab to detect and monitor metals on skin by self-sampling. This will contribute to better knowledge of metal skin exposure among dermatitis patients, workers, and the general population.

Theoretical modeling of a portable x-ray tube based KXRF system to measure lead in bone

Objective. K-shell x-ray fluorescence (KXRF) techniques have been used to identify health effects resulting from exposure to metals for decades, but the equipment is bulky and requires significant maintenance and licensing procedures. A portable x-ray fluorescence (XRF) device was developed to overcome these disadvantages, but introduced a measurement dependency on soft tissue thickness. With recent advances to detector technology, an XRF device utilizing the advantages of both systems should be feasible.Approach. In this study, we used Monte Carlo simulations to test the feasibility of an XRF device with a high-energy x-ray tube and detector operable at room temperature.Main Results. We first validated the use of Monte Carlo N-particle transport code (MCNP) for x-ray tube simulations, and found good agreement between experimental and simulated results. Then, we optimized x-ray tube settings and found the detection limit of the high-energy x-ray tube based XRF device for bone lead measurements to be 6.91 µg g−1 bone mineral using a cadmium zinc telluride detector.Significance. In conclusion, this study validated the use of MCNP in simulations of x-ray tube physics and XRF applications, and demonstrated the feasibility of a high-energy x-ray tube based XRF for metal exposure assessment.