Spectroscopic Assessment of Platinum Group Elements of PM10 Particles Sampled in Three Different Areas in Jeddah, Saudi Arabia.

Platinum group elements (PGE) including Ru, Rh, Pt and Pd have been quantified in air particulate matter with an aerodynamic diameter equal or less than 10 microns (PM10) using inductively coupled plasma mass spectrometry (ICP-MS). PM10 aerosols have been collected from three sites representing various activities in Jeddah city, Saudi Arabia. These locations are residential site with heavy traffic, industrial site and heavy traffic and a light traffic site outside the city. To obtain reasonable data of the PGE concentrations, a group from 10 to 15 PM10 samples were collected every month. The annual and seasonal variation of the mass concentration of the PGE were demonstrated. In all locations, Pt and Pd were relatively higher than Ru and Rh possibly because their main use is in automobile catalytic converters. Concentrations of observed PGE in PM10 could be arranged in ascending order as: Rh < Ru < Pd < Pt. In case of Ru and Pt, there are clear similarities in terms of the overall mean concentrations at the sampling locations. Due to the high concentration of Ru, Rh and Pd at low traffic site, there are certainly other sources of these elements rather than vehicle catalytic converters. However, at the industrial/heavy traffic location, high concentrations of Ru were detected during February 2015. In addition, high Pt concentrations were also detected at the light traffic site during May 2015. Results indicate that Pt source in PM10 is mainly the automobile catalytic converters.

Applicability of Low-Cost Binders for the Quantitative Elemental Analysis of Urinary Stones Using EDXRF Based on Fundamental Parameter Approach.

The pressed powder sample is a common method for elemental analysis using X-ray fluorescence analysis whereas suitable light hydrocarbon materials should be added to the sample as a binder. The present study demonstrates the applicability of using different commercial binders for elemental analysis of urinary stone samples. In order to confirm the obtained results, a comparison with pure chemical grade binders was presented. Different commercial and pure binders were tested for quantitative elemental analysis of urinary stones, namely, cellulose, starch, wax, and urea. Energy dispersive X-ray fluorescence (EDXRF) was used for elemental analysis. Differential thermal analysis was used to estimate the loss on ignition (LOI) in the urinary stone samples. The signal to background ratios (I/IB) of the different detected elements in the commercial and pure binders were calculated, compared, and studied at eight different photon energies starting from 2.5 up to 37 keV. Standard-less quantitative analysis method based on the fundamental parameter approach was applied for elemental analysis of selected urinary stones. The commercial and low-cost binders could be an excellent alternative binder for urinary stone analysis using energy dispersive X-ray fluorescence. The commercial binders could provide an advantage as pure chemical grade binders or even better especially at photon energy higher than 10 keV. The best commercial binder candidate was found to be the wax. The quantitative analysis results using commercial and pure chemical grade binders give good agreement results, which indicate the applicability of commercial binders for quantitative elemental analysis of urinary stones in the form of pressed powder samples.

An assessment of the inhalation bioaccessibility of platinum group elements in road dust using a simulated lung fluid.

Metal enrichment of road dust is well characterized but available data on the bioaccessibility of metals in particle size fractions relevant to human respiratory health remain limited. The study goal was to investigate the bioaccessibility of platinum group elements (PGE), which are used as catalysts in automotive exhaust converters, in the inhalable fraction of road dust. Street sweepings were provided by the City of Toronto, Canada, collected as part of its Clean Roads to Clean Air program.The particle size relevance of road dust for inhalation exposures was confirmed using a laser diffraction particle size analyzer (mean Dx(50): 9.42 µm). Total PGE were determined in both bulk and inhalable fractions using nickel sulfide (NiS) fire-assay and instrumental neutron-activation analysis (INAA). PGE lung solubility was examined for the inhalable fraction using Gamble's extraction. Sample digests were co-precipitated with Te-Sn, to pre-concentrate and isolate PGE, prior to their measurement using inductively coupled plasma mass spectrometry (ICP-MS).Total PGE concentrations were enriched in the inhalable fraction of road sweepings. Geomean concentrations in the inhalable fraction were: palladium (Pd) (152 µg/kg), platinum (Pt) (55 µg/kg), rhodium (Rh) (21 µg/kg) and iridium (Ir) (0.23 µg/kg). Osmium (Os) concentrations were below the limit of detection (LOD). Bioaccessible PGEs (n = 16) using Gamble's solution were below LOD for Ir and ruthenium (Ru). For the remainder, the geomean % bioaccessibility was highest for platinum (16%), followed by rhodium (14%) and palladium (3.4%). This study provides evidence that PGE in road dust are bioaccessible in the human lung.

Assessment of palladium footprint from road traffic in two highway environments.

Palladium (Pd) is an emerging eco-toxic pollutant from vehicle catalytic converters, emitted worldwide for more than two decades. Nowadays, the spatial extent of Pd fallout is growing along roads, but its subsequent fate in neighboring terrestrial ecosystems has not been extensively addressed yet. Two sites representative of contrasted natural environments (field, forest) but located under similar ambient conditions were selected to isolate and analyze the specific impact of vehicular Pd, along highway A71, France. Pd impregnation was assessed along 200-m-long transects perpendicular to the highway. Contents were measured in soils, earthworms, plant communities of the right of way (ROW), and the neighboring field (crop weeds), as well as in a moss, and bramble and ivy leaves in the forest. The direct impact of Pd fallouts appears to be confined in the grassy verge of the highway: ROW soils ([Pd] = 52-65 ng g(-1)), earthworms ([Pd] = 18-38 ng g(-1)), and plant community ([Pd] = 10-23 ng g(-1)). Pd footprint is pointed out by the accumulation index calculated for earthworms and plant communities even though transfer coefficients indicate the absence of bioaccumulation (TCs < 1). An indirect longer range transfer of Pd is identified, induced by hydric transport of organic matter.

A cost-effective and practical polybenzanthrone-based fluorescent sensor for efficient determination of palladium (II) ion and its application in agricultural crops and environment.

A highly selective and sensitive fluorescent chemosensor suitable for practical measurement of palladium ion (Pd(2+)) in agricultural crops and environment samples has been successfully fabricated using polybenzanthrone (PBA). PBA was facilely electrosynthesized in the mixed electrolyte of acetonitrile and boron trifluoride diethyl etherate. The fluorescence intensity of PBA showed a linear response to Pd(2+) in the concentration range of 5 nM-0.12 mM with a detection limit of 0.277 nM and quantification limit of 0.925 nM. Different compounds existing in agricultural crops and environment such as common metal ions, anions, natural amino acids, carbohydrates, and organic acids were used to examine the selectivity of the as-fabricated sensor, and no obvious fluorescence change could be observed in these interferents and their mixtures. A possible mechanism was proposed that the coordination of PBA and Pd(2+) enhance the aggregation of polymer chains, which led to a significant quenching of PBA emission, and this was further confirmed by absorption spectra monitoring and transmission electron microscopy. The excellent performance of the proposed sensor and satisfactory results of the Pd(2+) determination in practical samples suggested that the PBA-based fluorescent sensor for the determination of Pd(2+) will be a good candidate for application in agriculture and environment.

Experimental measurements and Monte Carlo calculations for (103)Pd dosimetry of the 12 mm COMS eye plaque.

Monte Carlo simulations and TLD dosimetry have been performed to determine the dose distributions along the central axis of the 12 mm COMS eye plaques loaded with IRA1-(103)Pd seeds. Several simulations and measurements have been employed to investigate the effect of Silastic insert and air in front of the eye on dosimetry results along the central axis of the plaque and at some critical ocular structures. Measurements were performed using TLD-GR200A circular chip dosimeters in a PMMA eye phantom. The central axis TLD chips locations were arranged in one central column of eye phantom, in 3 mm intervals. The off-axis TLD chips locations were arranged in three off-axis columns around the central axis column. Version 5 of the MCNP code was also used to evaluate the dose distribution around the plaque. The presence of the Silastic insert results in dose reduction of 14% at 5 mm; also about 7% dose reduction appears at the interface point, due to the air presence and lack of the scattering condition. The overall dosimetric parameters for the COMS eye plaque loaded with new palladium seeds are similar to a commercial widely used seed such as Theragenics200. As the dose calculations under TG-43 assumptions do not consider the effect of the plaque backing and Silastic insert for accurate dosimetry, it's suggested to apply the effect of the eye plaque materials and air on dosimetry results along the central axis of the plaque and at some critical ocular structures.

Monte Carlo calculation of dosimetry parameters for the IR08-103Pd brachytherapy source.

PURPOSE: For the treatment of some cancerous tumors using brachytherapy methods and low-energy photon sources, such as 125I and 103Pd, the American Association of Physicists in Medicine Task Group No. 43U1 report recommends that the dosimetric parameters of a new brachytherapy source must be determined in two experimental and Monte Carlo theoretical methods before using each new source clinically. This study presents the results of Monte Carlo calculations of the dosimetric parameters for IR08-103Pd brachytherapy source design. IR08-103Pd seed has been manufactured at the Agricultural, Medical and Industrial Research School. METHODS: Version 5 of the (MCNP) Monte Carlo radiation transport code was used to calculate the dosimetry parameters around the source. Three geometric models of the seed, based on different locations of beads inside the titanium capsule, were simulated. The seed contains five resin beads of 0.6 mm diameter having 103Pd uniformly absorbed in the bead volume, which were contained within a cylindrical titanium capsule having 0.8 mm outside diameter and 4.8 mm length. RESULTS: The Monte Carlo calculated dose rate constant of the IR08-103Pd seed was found to be 0.695 +/- 0.021 cGyU(-1) h(-1). Also in this study, the geometry function G(r, theta), line and point-source radial dose functions gL(r) and gP(r), and the anisotropy function F(r, theta), have been calculated at distances from 0.25 to 7 cm. The results of these calculations have been compared with measured values for an actual IR08-103Pd seed. CONCLUSIONS: There are no statistical significant dosimetric differences among the three seed orientations in this study (i.e., ideal, vertical, and diagonal). However, the observed differences between the calculated and measured values could be explained by the measurement uncertainty and the configuration of the resin beads within the capsule and capsule orientation.

Platinum-group elements in sewage sludge and incinerator ash in the United Kingdom: assessment of PGE sources and mobility in cities.

Platinum-group element (PGE) concentrations in sewage sludge and incinerator ash compared with average PGE concentrations in road dust show a common pattern, characterized by a negative Rh anomaly. This similarity, found at 9 UK incinerators, suggests that there is a universal characteristic PGE pattern produced by common processes of dispersal of Pt, Pd and Rh derived from automobile catalytic converters. Ninety-one sewage sludge and incinerator ash samples from the sewage treatment facilities in Sheffield, Birmingham and 7 other UK cities were analyzed for PGE. The highest concentrations are 602ppb Pt and 710ppb Pd with lower maximum concentrations of 65ppb Rh, 100ppb Ru, 33ppb Ir and 12ppb Os. Ash from incinerated sewage was found to have higher PGE concentrations compared to the original sludge and the PGE ratios are preserved during incineration. Rh is more mobilized and dispersed than the other PGE as it is transported from roads into the drainage system and into sewage. Pt/Pd ratios of 1.0 in road dust and 0.9 in sewage and incinerator ash suggest that Pd is more mobile than Pt during dispersal. PGE abundances in stored incinerator ash of varying ages appear to have been affected by the variation in use of Pt, Pd and Rh in catalytic converters due to variation in their market prices. Concentrations of Os, Ir and Ru in ashes are greater in Sheffield and London than all the other city sites and may be derived from point industrial sources.

On the re-assessment of the optimum conditions for the determination of platinum, palladium and rhodium in environmental samples by electrothermal atomic absorption spectrometry and microwave digestion.

The experimental conditions for the determination of platinum, palladium and rhodium by graphite furnace atomic absorption spectrometry (GFAAS) are re-assessed. A certified material (BCR-723) was used as a working sample and analyzed using various extraction and atomization procedures in order to find the optimal experimental conditions that enable the quantitative and reproducible detection of platinum, palladium and rhodium in environmental matrices. Evidently, literature observations regarding the atomization conditions were proven fairly adequate. However, the provision of the optimum extraction conditions revealed several parameters that lie behind the reported uncertainties. The appropriate combination between extraction conditions and atomization programs afforded a considerable improvement in the recoveries and analytical features of platinum, palladium and rhodium determination with GFAAS. Cross-examination of the analytical data with various CRMs (certified reference materials) was used to validate the robustness of the method in heterogeneous matrices bearing different element levels. Under the optimum experimental conditions the method permits the determination at concentrations as low as (LOD(3S/N)) 1.9 ng g(-1), 0.45 ng g(-1) and 0.6 ng g(-1) for Pt, Pd and Rh, respectively affording recoveries in the range of 93-101%. The method was successfully applied to the assessment of Pt, Pd and Rh accumulation in real road dust and soil samples in Greece.

Monte Carlo and experimental characterization of the first AMIRS 103Pd brachytherapy source.

TG-43U1 dosimetric parameters of a new brachytherapy (103)Pd source, including dose-rate constant, radial dose function, 2D anisotropy function, 1D anisotropy function and anisotropy constant, have been determined using MCNP4C code and have been verified by measurements in Perspex phantoms, using TLD-100 dosimeters calibrated in (60)Co radiation field. The comparison of calculated and measured dosimetric parameters showed the validity of Monte Carlo calculations and experimental results. The anisotropy constant was calculated as 0.87 in water and 0.88 in Perspex; and measured as 0.92 in Perspex. Comparing dosimetric parameters of the new source with other source models showed acceptable agreement.

Monte Carlo calculations and experimental measurements of dosimetric parameters of the IRA-103Pd brachytherapy source.

This article presents a brachytherapy source having 103Pd adsorbed onto a cylindrical silver rod that has been developed by the Agricultural, Medical, and Industrial Research School for permanent implant applications. Dosimetric characteristics (radial dose function, anisotropy function, and anisotropy factor) of this source were experimentally and theoretically determined in terms of the updated AAPM Task group 43 (TG-43U1) recommendations. Monte Carlo simulations were used to calculate the dose rate constant. Measurements were performed using TLD-GR200A circular chip dosimeters using standard methods employing thermoluminescent dosimeters in a Perspex phantom. Precision machined bores in the phantom located the dosimeters and the source in a reproducible fixed geometry, providing for transverse-axis and angular dose profiles over a range of distances from 0.5 to 5 cm. The Monte Carlo N-particle (MCNP) code, version 4C simulation techniques have been used to evaluate the dose-rate distributions around this model 103Pd source in water and Perspex phantoms. The Monte Carlo calculated dose rate constant of the IRA-103Pd source in water was found to be 0.678 cGy h(-1) U(-1) with an approximate uncertainty of +/-0.1%. The anisotropy function, F(r, theta), and the radial dose function, g(r), of the IRA- 103Pd source were also measured in a Perspex phantom and calculated in both Perspex and liquid water phantoms.

Experimental measurements and Monte Carlo calculations of dosimetric parameters of the IRA1-103Pd brachytherapy source.

This work presents a brachytherapy source having (103)Pd adsorbed onto a cylindrical silver rod that has been developed by Agricultural, Medical and Industrial Research School for permanent implant applications. Dosimetric characteristics (dose-rate constant, radial dose function, anisotropy function and anisotropy factor) of this source were experimentally and theoretically determined in terms of the updated AAPM Task Group 43 (TG-43U1) recommendations. Measurements were performed using TLD-GR200A circular chip dosimeters using standard methods employing thermoluminescent dosimeters in a Perspex phantom. Precision machined bores in the phantom located dosimeters and source in a reproducible fixed geometry providing for transverse-axis and angular dose profiles over a range of distances from 0.5 to 5 cm. The Monte Carlo N-Particle (MCNP) code, version 4C was used to evaluate the dose-rate distributions around this model (103)Pd source in water and Perspex phantoms. The Monte Carlo calculated dose-rate constant of the IRA1-(103)Pd source in water was found equal to Lambda=0.669 cGy/h/U with approximate uncertainties of +/-0.1%. The anisotropy function, F(r, theta), and the radial dose function, g(L)(r), of the IRA1-(103)Pd source were also measured in Perspex phantom and calculated in both Perspex and liquid water phantom.

Monte Carlo dosimetric characterization of the IsoAid ADVANTAGE 103Pd brachytherapy source.

For roughly 25 years, 125I and 103Pd sources have been used in the treatment of various malignant diseases such as prostate cancer. Various new sources have been marketed and produced to meet the demand for new sources to use in treatment. Recently, IsoAID LLC created the ADVANTAGE 103Pd source. Various dosimetric parameters must be determined to facilitate treatment planning using this source. Theoretical determination of dosimetric characteristics, dose rate constant, radial dose function, and anisotropy function for this new source followed the American Association of Physicists in Medicine (AAPM) Task Group 43U1 recommendations. Theoretical calculations were performed in liquid water using the PTRAN Monte Carlo code version 7.44. The radial dose function of the new source was calculated in liquid water at distances up to 10.0 cm, and the anisotropy function, at distances ranging from 0.5 cm to 7.0 cm. The anisotropy factors and anisotropy constant were derived from the anisotropy function. The results in water indicate that the dose rate constant is 0.709 +/- 0.014 cGy x h-1 x U-1 and that the anisotropy constant is 0.880 +/- 0.040. The dosimetric characteristics of this new source compare favorably with those of other commercially available 103Pd sources.

AAPM TG-43U1 formalism adaptation and monte carlo dosimetry simulations of multiple-radionuclide brachytherapy sources.

This paper presents a preliminary study on multiple-radionuclide sources for brachytherapy. An adaptation of the AAPM TG-43U1 formalism is proposed in order to derive the dosimetry parameters of multiple-radionuclide sources from mono-radionuclides. The adapted formalism is applied to a bi-radionuclide case with the help of Monte Carlo calculations (MCNPX 2.5.0). InterSource seed loaded with 103Pd and 125I was chosen. This combination promotes a higher dose rate than InterSource125 (loaded with 125I) and deeper tissue penetration than InterSource103 (loaded with 103Pd) while reducing the dose at long distance (beyond 2.5 cm) relative to InterSource125. In conclusion, this work shows the benefits of combining different radionuclides inside the same seed and proposes an adaptation of the AAPM TG-43U1 formalism for the implementation of multiple-radionuclide sources in current treatment planning systems.

Assessment of workers' exposure to palladium in a catalyst production plant.

Airborne particulate matter was collected and biomonitoring of workers was performed by sampling blood, urine and hair of 84 exposed subjects, 17 occasionally exposed employees, 21 controls from administrative offices and 25 unexposed people (external controls). Determination of Pd was performed using Quadrupole and High Resolution Inductively Coupled Plasma Mass Spectrometry. The Production of Catalysts Department and the Refining Service presented the highest levels of Pd in airborne matter collected by means of an area sampler. The highest level of soluble Pd (1.66 microg m(-3)) was found in the Production of Catalysts Department. The highest concentration of Pd in airborne matter, collected by means of personal devices (7.90 microg m(-3)) was found in the Refining Service. Hair showed a clear distribution pattern among departments, with values ranging from 0.60 to 5.54 microg g(-1). Administrative workers presented blood levels of Pd between 2 and 500 times higher than external controls. Only urine levels correlated with the measurements of airborne Pd collected with personal devices. A very strong association between airborne Pd collected by personal devices and Pd levels in hair (r(2)= 0.569, with p< or = 0.01) and urine (r(2)= 0.684, with p< or = 0.01) was found. On the basis of these findings: (i) blood results appear to be an unsuitable biological marker for occupational exposure to Pd; (ii) urine could be considered as a satisfactorily responsive bio-marker for occupational monitoring; and (iii) hair cannot be considered a good index of time-related exposure.

Dosimetric characteristics of the new RadioCoil 103Pd wire line source for use in permanent brachytherapy implants.

Recently, a novel linear brachytherapy source in the form of a coiled wire has become available for use in interstitial implants of various treatment sites such as prostate gland. This source type employs a design completely different from that of most "seed" sources currently on the market, one which improves upon or eliminates several common problems with such sources. Dosimetric characteristics of these sources with active lengths 0.5 cm to 5.0 cm were determined for clinical application. For 0.5 cm and 1.0 cm active length sources, the dose rate constant, radial dose function, and two-dimensional (2D) anisotropy function were experimentally and theoretically determined following the updated AAPM Task Group 43 (TG-43U1) recommendations. Radial dose functions and/or "along-away" matrix functions were also obtained for sources with active lengths 2.0 cm to 5.0 cm. Measurements were performed with LiF thermoluminescent dosimeters in Solid Water phantoms. Measured data was compared to Monte Carlo simulated data in Solid Water utilizing the PTRAN code, version 7.43. After finding the data to be in agreement, Monte Carlo calculations were performed in liquid water to obtain clinically applicable dosimetric data as per TG-43U1 recommendations. The results indicated the dose rate constant of the 0.5 cm long RadioCoil 103Pd source in Solid Water to be 0.641 cGy h(-1) U(-1) when measured, and 0.636 cGy h(-1) U(-1) when simulated by Monte Carlo. The calculated dose rate constant in liquid water was found to be 0.650 cGy h(-1) U(-1). These values are comparable to other commercially available sources. Complete dosimetric data and simulation results are described in this paper. Per TG-43U1, clinical treatment planning systems should utilize the values reported for liquid water.

Brachytherapy dosimetry parameters calculated for a new 103Pd source.

A new brachytherapy source having 103Pd adsorbed onto silver beads has been designed. The dose distributions of this source have been characterized using version 5 of the MCNP Monte Carlo radiation transport code available from Oak Ridge National Laboratory. These results are presented in terms of the updated AAPM Task Group No. 43 (TG-43U1) formalism, dosimetry parameters, and recommended calculation methodology.

An evaluation of the environmental and health effects of vehicle exhaust catalysts in the UK.

Since 1993, all new gasoline-engine automobiles in the United Kingdom have been supplied with three-way vehicle exhaust catalytic converters (VECs) containing platinum, palladium, and rhodium, to comply with European Commission Stage I limits on emissions of regulated pollutants: carbon monoxide, hydrocarbons, and oxides of nitrogen. We conducted a physical and economic evaluation of the environmental and health benefits from a reduction in emissions through this mandated environmental technology against the costs, with reference to urban areas in Great Britain. We made both an ex post assessment--based on available data to 1998--and an ex ante assessment--projected to 2005, the year when full penetration of VECs into the fleet is expected. Substantial health benefits in excess of the costs of VECs were indicated: By 1998 the estimated net societal health benefits were approximately 500 million British pounds, and by 2005 they were estimated to rise to as much as 2 billion British pounds. We also found through environmental surveys that although lead in road dust has fallen by 50% in urban areas, platinum accumulations near roads have risen significantly, up to 90-fold higher than natural background levels. This rapid accumulation of platinum suggests further monitoring is warranted, although as yet there is no evidence of adverse health effects.