Fathi Zereini

Airborne particulate matter, platinum group elements and human health: a review of recent evidence.

Environmental concentrations of the platinum group elements (PGE) platinum (Pt), palladium (Pd) and rhodium (Rh) have been on the rise, due largely to the use of automobile catalytic converters which employ these metals as exhaust catalysts. It has generally been assumed that the health risks associated with environmental exposures to PGE are minimal. More recent studies on PGE toxicity, environmental bioavailability and concentrations in biologically relevant media indicate however that environmental exposures to these metals may indeed pose a health risk, especially at a chronic, subclinical level. The purpose of this paper is to review the most recent evidence and provide an up-to-date assessment of the risks related to environmental exposures of PGE, particularly in airborne particulate matter (PM). This review concludes that these metals may pose a greater health risk than once thought for several reasons. First, emitted PGE may be easily mobilised and solubilised by various compounds commonly present in the environment, thereby enhancing their bioavailability. Second, PGE may be transformed into more toxic species upon uptake by organisms. The presence of chloride in lung fluids, for instance, may lead to the formation of halogenated PGE complexes that have a greater potential to induce cellular damage. Third, a significant proportion of PGE found in airborne PM is present in the fine fraction that been found to be associated with increases in morbidity and mortality. PGE are also a concern to the extent that they contribute to the suite of metals found in fine PM suspected of eliciting a variety of health effects, especially in vulnerable populations. All these factors highlight the need to monitor environmental levels of PGE and continue research on their bioavailability, behaviour, speciation and associated toxicity to enable us to better assess their potential to elicit health effects in humans.

Geochemical behaviour of platinum-group elements (PGE) in particulate emissions by automobile exhaust catalysts: experimental results and environmental investigations

Abstract The increasing use of automobile catalysts leads to the emission of the platinum-group elements (PGE) platinum, rhodium and palladium into the environment. Experiments were conducted in order to assess the possibility of their mobility caused by species transformation. Soil material was contacted with a ground catalyst and, after varying parameters such as pH, chloride or sulfur concentration, the solubility of platinum and rhodium was measured. Laboratory results were compared with those from different environmental materials (soil, run-off sediments, surface waters, tunnel dust). Analytical techniques were GFAAS (after preconcentration by nickel sulfide fire assay), XRF, ICP-MS, AV, XPS and SIMS. Experimental results show that small, although significant, amounts of platinum and rhodium are adsorbed in soil or soluble in surface waters. Environmental materials exhibit a relatively constant Pt/Rh ratio of 5, which points to a common source, the automobile catalysts. A direct determination of PGE species by surface analysis is still not possible, due to low surface concentrations. As most of the PGE seem to behave in an inert manner and are immobile they do not constitute a hazard to health.

Platinum group elements (Pt, Pd, Rh) in airborne particulate matter in rural vs. urban areas of Germany: Concentrations and spatial patterns of distribution

This study examines platinum group element concentrations (PGE) (i.e. platinum (Pt), palladium (Pd) and rhodium (Rh)) and their spatial distribution in airborne particulate matter fractions (PM) of human health concern in urban and rural areas of Germany. Fractionated airborne dust and PM(10), PM(2.5) and PM(1) samples were collected along a busy road in Frankfurt am Main from July 2008 to April 2010. PM(10) was also sampled in Deuselbach and Neuglobsow between January 2008 and July 2009 to examine their concentrations at rural locations and potential for long-range transport. Pt, Pd and Rh were isolated and pre-enriched in samples using a combination of Te and Hg co-precipitation methods. Concentrations were determined using isotope dilution ICP-Q-MS (in collision mode with He). The highest airborne PGE concentrations were measured in PM(10) from Frankfurt (e.g. 12.4pg Pt/m(3) (mean)), while the rural locations of Deuselbach and Neuglobsow exhibited the lowest levels (e.g. 2pg Pt/m(3) (mean)). PGE concentrations were observed to decline with increasingly smaller PM size fractions from PM(10) to PM(1). All size fractions generally contained higher levels of Pd compared to Pt and Rh, an element of greater concern due to its solubility. PM(2.5) collected in Frankfurt had a mean of 16.1pg Pd/m(3), compared to 9.4pg/m(3) for Pt. PGE concentrations also demonstrated a distinct seasonal relationship, with the greatest levels occurring in winter. Compared to a previous study in 2002, PGE concentrations in fractionated airborne dust have significantly increased over time. Elevated PGE levels were also measured for PM(10) sampled in Neuglobsow and Deuselbach, which could not be attributed to local emission sources. Using the diagnostic meteorological model, CALMET, trajectory analyses confirmed our hypothesis that PGE are being transported over longer distances from other areas of Europe.

Verteilung von Platingruppenelementen (PGE) in den Umweltkompartimenten Boden, Schlamm, Straßenstaub, Straßenkehrgut und Wasser

ZusammenfassungErhöhte Platin-, Rhodium- und Palladium-Konzentrationen in Umweltproben aus der Umgebung von Straßen weisen auf Kraftfahrzeuge mit Abgaskatalysator als Emissionsquelle hin. Der Studie zufolge emittieren pro Katalysator ca. 270 ng/km Platin, wobei die Emission der Platinmetalle überwiegend in partikulärer Form durch mechanischen Abrieb des Katalysatorsmaterials erfolgt. Die Analyse verschiedener Umweltkompartimente verweist auf die geringe Löslichkeit von Platin und Rhodium unter atmosphärischen Bedingungen.Die ermittelten Daten sollen dazu dienen, weitere Konzentrationsveränderungen dieser Elemente zu verfolgen und gleichzeitig die Auswirkungen von Platinmetall-Emissionen auf die Umwelt kurz- und langfristig einzuschätzen.AbstractThe growing use of catalytic converters for exhaust control in automobiles leads to increasing emissions of platinum-group elements (PGE) into the environment. Measurements of soil, mud, dust and sweepings along roadsides were undertaken at the Institute of Geochemistry to quantify these emissions of platinum, rhodium and palladium.When compared to normal geochemical background values, the results reveal elevated PGE concentrations in the vicinity of roads, especially for platinum. An observed positive correlation between the amounts of PGE and the density of traffic provides an indication for the source as stemming from the mechanical abrasion of the materials in catalytic converters. The analysis of various environmental compartments reveals a slight solubility of platinum and rhodium under atmospheric conditions.The data thus obtained will serve to help in monitoring the future developments and as an aid for assessing the long and short-term effects of platinum emissions on the environment.

Konzentration und Verteilung von Platingruppenelementen (PGE) in Böden

ZusammenfassungDer zunehmende Einsatz von Abgaskatalysatoren in Kraftfahrzeugen könnte dazu führen, daß bei Abrieb des Katalysatormaterials eine erhöhte Platinmetall-Emission erfolgt und es damit zu einer Belastung der Umwelt mit Platingruppenelementen kommt.Um die derzeitigen Konzentrationen von Platingruppenelementen (PGE) in Böden zu ermitteln, wurden im Rahmen eines Forschungsprojekts des Instituts für Geochemie, Petrologie und Lagerstättenkunde der J. W. Goethe-Universität Frankfurt mit dem Thema „Bodenbelastung durch Platingruppenelemente entlang der Autobahnstrecke A66 Frankfurt-Wiesbade” systematisch 71 oberflächennahe Bodenproben entnommen und auf ihre PGE-Konzentrationen analysiert.Die Analysenergebnisse zeigen, daß die Platinkonzentrationen im Durchschnitt 10 μg/kg betragen. Sowohl für Palladium als auch für Rhodium liegen die Konzentrationen bei < 2 μg/kg und für Ruthenium bei 3 μg/kg. Ferner wurde festgestellt, daß mit zunehmender Entfernung vom Autobahnrand die PGE-Konzentrationen abnehment und in etwa 20 m Entfernung von der Autobahn mit dem angewandten Analysenverfahren nicht mehr nachzuweisen sind. Die Platingruppenelemente sind ausschließlich oberflächennah in den oberen 20 cm der Böden in meßbaren Konzentrationen vorhanden. Diese Ergebnisse zeigen bereits heute anormale PGE-Konzentrationen in den betroffenen Böden entlang der untersuchten Autobahnstrecke. Sie können dazu dienen, einen zu vermutenden weiteren Anstieg der PGE-Konzentrationen zeitabhängig zu kontrollieren.AbstractIn Germany automobile exhaust control by platinum-group element (PGE) loaded catalysts is now well established. By mechanical or chemical attrition, these catalysts could act as a potential source for a significant increase of PGE abundances in the environment. During a recent research program concentrations and distributions of PGE in different soils were measured along the highway A66 Frankfurt-Wiesbaden. 71 nearsurface soil samples were analysed by graphite furnace atomic absorption spectrometry (GFAAS). The results revealed average abundances of 10 ppb platinum and 3 ppb ruthenium. Palladium as well as rhodium were below the analytical detection limit of 2 ppb. With increasing distance from the highway edge PGE values gradually decreased. Only the upmost soil layer, down to 20 cm depth, contains measurable PGE concentrations. Results: There are irregular PGE concentrations of anthropogenic origin in different soils along the highway A66 Frankfurt-Wiesbaden possibly arising from automobile exhaust catalysts. Further monitoring could help to avoid potential environmental hazards. *** DIRECT SUPPORT *** A00HP020 00002

Palladium Emissions in the Environment

To date the investigations of metal emissions from automotive catalysts has focused mainly on platinum. Since 1993, however, platinum has been increasingly replaced by palladium as the predominant substance in pollution-control catalysts. Now the release of palladium in automotive catalysts is becoming just a critical problem as that of platinum. The editors present the latest research results related to all aspects of palladium emissions in the environment, as well as an assessment of their effects on the environment and health. The book focuses on the following topics: analytical methods; sources of palladium emissions; occurrence, chemical behaviour and fate in the environment; bioavailability and biomonitoring; and health-risk potential.

Traffic-related trace element fate and uptake by plants cultivated in roadside soils in Toronto, Canada

This research examines traffic-related trace element emissions and their uptake by plants grown in urban roadside environments in Toronto, Canada. Oregano (Origanum vulgare), beets (Beta vulgaris) and eggplants (Solanum melongena) were cultivated at four locations with variable traffic-related metal inputs in 2010. The top 30 cm of soil at the medium-traffic location was first replaced with a triple mix soil (topsoil, compost and peat) to control for pre-existing contamination. The same soil was used to cultivate at the two no/low traffic locations. Soil at the heavy traffic location was not remediated. Soil, plant tissue and plant rhizosphere samples were collected for the analysis of a range of traffic-related metal(loids) using ICP-MS, including Cr, Mn, Cu, Ni, Cd, As, Sb and Pb. Samples were digested with HNO(3) and HCl using a microwave-assisted digestion procedure and then treated with HF prior to analysis. Two certified reference materials, San Joaquin soil (NIST 2709a) and trace elements in spinach leaves (NIST 1570a), were used for QA/QC purposes. Metal(loid) concentrations and accumulation over time were highly variable at the medium traffic site where the soil was replaced. Mn (p<0.10), As (p<0.10) and Sb (p<0.01) concentrations significantly increased in bulk soils from May to November 2010, while Ce (p<0.01) and Cd (p<0.10) levels decreased. For instance, median As concentrations increased from 4.39 to 8.40 mg/kg over this period. Metals were found to be more bioaccessible to O. vulgare grown in the new soil at the medium traffic volume site, compared to the aged soil at the heavy traffic location. Several elements, most notably Cd, were also found to accumulate in the root zone of sampled S. melongena. Metal concentrations in S. melongena rhizosphere were better predictors of plant tissue levels, providing evidence that soil quality guidelines based on total metal concentrations for bulk soils are inadequate.

Sources of anthropogenic platinum-group elements (PGE): Automotive catalysts versus pge-processing industries

Soil samples from the area of Hanau (Hessen, Germany) were analyzed for anthropogenic platinum-group elements (PGE). The results confirm the existence of two different sources for anthropogenic PGE: 1. automotive catalysts, and 2. PGE-processing plants. Both sources emit qualitatively and quantitatively different PGE spectra and PGE interelemental ratios (especially the Pt/Rh ratio). Elevated PGE values which are due to automotive catalysts are restricted to a narrow-range along roadside soil, whereas those due to PGE-processing plants display a large-area dispersion. The emitted PGE-containing particles in the case of automotive catalysts are subject to transport by wind and water, whereas those from PGE-processing plants are preferably transported by wind. This points to a different aerodynamic particle size. Pt, Pd, and Rh concentrations along motorways are dependent on the amount of traffic and the driving characteristics.

In Vitro Investigations of Platinum, Palladium, and Rhodium Mobility in Urban Airborne Particulate Matter (PM10, PM2.5, and PM1) Using Simulated Lung Fluids

Environmental concentrations of platinum group elements (PGE) have been increasing since the introduction of automotive catalytic converters to control harmful emissions. Assessments of the human health risks of exposures to these elements, especially through the inhalation of PGE-associated airborne particulate matter (PM), have been hampered by a lack of data on their bioaccessibility. The purpose of this study is to apply in vitro methods using simulated human lung fluids [artificial lysosomal fluid (ALF) and Gambles solution] to assess the mobility of the PGE, platinum (Pt), palladium (Pd), and rhodium (Rh) in airborne PM of human health concern. Airborne PM samples (PM(10), PM(2.5), and PM(1)) were collected in Frankfurt am Main, Germany. For comparison, the same extraction experiments were conducted using the standard reference material, Used Auto Catalyst (monolith) (NIST 2557). Pt and Pd concentrations were measured using isotope dilution ICP-Q-MS, while Rh was measured directly with ICP-Q-MS (in collision mode with He), following established matrix separation and enrichment procedures, for both solid (filtered residues) and extracted sample phases. The mobilized fractions measured for PGE in PM(10), PM(2.5), and PM(1) were highly variable, which can be attributed to the heterogenic nature of airborne PM and its composition. Overall, the mobility of PGE in airborne PM samples was notable, with a mean of 51% Rh, 22% Pt, and 29% Pd present in PM(1) being mobilized by ALF after 24 h. For PM(1) exposed to Gambles solution, a mean of 44% Rh, 18% Pt, and 17% Pd was measured in solution after 24 h. The mobility of PGE associated with airborne PM was also determined to be much higher compared to that measured for the auto catalyst standard reference material. The results suggest that PGE emitted from automotive catalytic converters are likely to undergo chemical transformations during and/or after being emitted in the environment. This study highlights the need to conduct bioaccessibility experiments using samples collected in the field to enable an adequate assessment of risk.

Climatic changes and water resources in the Middle East and North Africa

Global Climate Changes - Sources and Impacts on the Water Cycle.- Climate Change and Water Cycle - Some Lessons from the Geological Past.- Climate Change and the Water Cycle - Some Information Concerning Precipitation Trends.- Moroccan Climate in the Present and Future: Combined View from Observational Data and Regional Climate Scenarios.- Impact of Climate Change on Water Availability in.- Climatic Changes in Lebanon, Predicting Uncertain Precipitation Events - Do Climatic Cycles Exist?.- Impact of Climate Change on Water Resources.- Water Resources Management in the Middle East under Aspects of Climatic Changes.- Virtual Water Trade as an Adaptation Demand Management of Climate Change Impact on Water Resources in the Middle East.- The Impacts of Climate Change on Water Resources in Jordan.- Impact of Climate Change on Water Resources of Lebanon: Indications of Hydrological Droughts.- The Impact of Global Warming on the Water Resources of the Middle East: Past, Present, and Future.- Decadal Precipitation Variances and Reservoir Inflow in the Semi-Arid Upper Draa Basin (South- Eastern Morocco).- Management Options for a Sustainable Groundwater Use in the Middle Draa Oases under the Pressure of Climatic Changes.- Water Resources and Water Management.- A Decision Support System (DSS) for Water Resources Management, - Design and Results from a Pilot Study in Syria.- Management Strategies of Water Resources in the Arid Zone of South-Eastern Morocco.- The Role of Groundwater During Drought in Tunisia.- The Evolution of Groundwater Exploration Methods in the Moroccan Oases through History, and Managing Ecological Risk of their Present Pollution.- Investigating Unconsolidated Aquifers in an Arid Environment - A Case Study from the Lower Jordan Valley/Jordan.- Water Resources Protection Efforts in Jordan and their Contribution to a Sustainable Water Resources Management.- Model Investigations on the Groundwater System in Jordan - A Contribution to the Resources Management (National Water Master Plan).- Seawater Intrusion in Greater Beirut, Lebanon.- Long Term (1970 - 2001) Eco-Hydrological Processes in Lake Kinneret and its Watershed.- Transfer of the Concepts of the European Water Framework Directive to Arid and Semiarid Regions.- Seal Formation Effects on Soil Infiltration and Runoff in Arid and Semiarid Regions under Rainfall and Sprinkler Irrigation Conditions.- Restoring the Shrinking Dead Sea - The Environmental Imperative -.- Groundwater in the Shallow Aquifer of the Jericho Area, Jordan Valley - Noble Gas Evidence for Different Sources of Salinization.- The Interaction of Population Dynamics and Transformations in Water Supply Systems in the Jordan River Basin.