Eckard Helmers

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.

European hospitals as a source for platinum in the environment in comparison with other sources

The concentration of platinum in the sewage of five European hospitals originating from excreted antineoplastic drugs, cisplatin and carboplatin, was analyzed in a short term study to provide an order of magnitude of Pt emissions from hospitals into aquatic environments. These emissions were compared with a rough estimation of emissions by cars. The average daily concentrations in the hospital effluents were approximately < 10-601 ng l-1 Pt (20-3580 ng l-1 in 2-h mixed samples). As expected from consumption data, the daily average concentrations should range from < 10-710 ng l-1 Pt. Platinum emitted by hospitals is 3.3-12.3% (1.3-14.3 kg per year) the estimated amount emitted by cars equipped with catalytic converters in the different European countries. Compared to platinum emissions from other sources, the effluents of hospitals are a minor source of platinum in municipal sewage, but they should not to be disregarded. Other possible sources for the emission of platinum into the environment should be considered in further investigations.

Distribution of platinum group elements (Pt, Pd, Rh) in environmental and clinical matrices: Composition, analytical techniques and scientific outlook: Status report.

Trace concentrations of the platinum group elements (PGE; here: Pt, Pd and Rh) play an important role in environmental analysis and assessment. Their importance is based on 1. their increasing use as active compartments in automobile exhaust catalysts, 2. their use as cancer anti-tumor agents in medicine. Due to their allergenic and cytotoxic potential, it is necessary to improve selectivity and sensitivity during analytical investigation of matrices like soil, grass, urine or blood.This paper summarizes the present knowledge of PGE in the fields of analytical chemistry, automobile emission rates, bioavailibility, toxicology and medicine.

Comparison of palladium and platinum in environmental matrices: Palladium pollution by automobile emissions?

A new type of automobile catalyst based on an active Pd/Rh-layer is presently being introduced into the European market. Accordingly, in order to establish baseline information, this work attempts to assess the magnitude of Pd emissions by automobile catalysts to date. Thus, a survey is presented on Pd and Pt levels detected in polluted environmental matrices (grass, soil, dust, sludges) as available from the literature. Additionally, Pd data measured by selective preconcentration/GF-AAS-detection in polluted grass, in a time series of sewage sludge ashes back to 1972, in dust, as well as in urban rain are presented. Since the data basis from the literature is partly inconsistent, the possible impact of different analytical attempts on the data is discussed. The relationship between Pt and Pd concentration from most of the results is between 5 and 10 (Pt/Pd). However, relations down to 0.04 are also reported, thus implying anthropogenic Pd input from additional sources.

Hospital effluents as a source for platinum in the environment

Abstract The fact that catalytic converters emit platinum into the environment is well known. Other possible sources such as plastics, fertilizers or tyres are being considered. However, the detectable concentrations of platinum in the environment are higher than those calculated from experiments with isolated engines testing these emissions. Another possible source of platinum is effluents from hospitals which contain platinum from excreted anti-neoplastic drugs, cisplatin and carboplatin. The concentration of platinum in the sewage of various hospitals and hospital departments was determined and the detected concentrations were approximately 110–176 ng/l Pt during the daytime and approximately 38 ng/l Pt at night. As calculated from annual consumption data, the concentrations should range from 110–210 ng/l Pt. Compared to platinum emissions from other sources the effuents of hospitals are not the most important ones, but they should not be disregarded.

Platin in Klärschlammasche und an Gräsern

ZusammenfassungPlatin- und Bleigehalte wurden in Gräsern aus Autobahnnähe gemessen. Platin konnte außerdem in Proben von Klärschlammasche retrospektiv bis zum Jahr 1972 bestimmt werden. Der nach 1987 gefundene Anstieg ließ sich auf Pt-Emissionen aus KFZ-Abgaskatalysatoren zurückführen. Die Größenordnung der Emissionsrate von Katalysator-Fahrzeugen konnte aus dem Vergleich mit Blei abgeschätzt werden.AbstractConcentrations of platinum and lead were measured in common grass sampled near the Autobahn. Additionally, platinum was determined in spot checks of ash from seawage sludge incinerators to 1972. The increase in Pt levels since 1987 was traced back to releases from automobile catalytic converters. The emission rate of a car equipped with a catalytic converter has been estimated by comparison with Pb.

Elements accompanying platinum emitted from automobile catalyst's

Abstract Samples of common grass collected in the vicinity of a motorway were analyzed by ICP-MS in order to identify some elements showing a concentrational increase in parallel to Pt (years 1992 – 1994). The amounts of Al, Ce, La, Nd and Zr increased significantly within the sampling period and were recognized to be part of automobile catalyst emissions. Concentrational behavior of Ce and its relation to Pt were investigated in detail. Conditions for the prediction of Pt concentrations from a corresponding Ce distribution are reported. It is shown that Pt detected along streets should be attributed to catalyst emissions.

Electric cars: technical characteristics and environmental impacts

BackgroundElectric vehicles have been identified as being a key technology in reducing future emissions and energy consumption in the mobility sector. The focus of this article is to review and assess the energy efficiency and the environmental impact of battery electric cars (BEV), which is the only technical alternative on the market available today to vehicles with internal combustion engine (ICEV). Electricity onboard a car can be provided either by a battery or a fuel cell (FCV). The technical structure of BEV is described, clarifying that it is relatively simple compared to ICEV. Following that, ICEV can be ‘e-converted’ by experienced personnel. Such an e-conversion project generated reality-close data reported here.ResultsPracticability of todays BEV is discussed, revealing that particularly small-size BEVs are useful. This article reports on an e-conversion of a used Smart. Measurements on this car, prior and after conversion, confirmed a fourfold energy efficiency advantage of BEV over ICEV, as supposed in literature. Preliminary energy efficiency data of FCV are reviewed being only slightly lower compared to BEV. However, well-to-wheel efficiency suffers from 47% to 63% energy loss during hydrogen production. With respect to energy efficiency, BEVs are found to represent the only alternative to ICEV. This, however, is only true if the electricity is provided by very efficient power plants or better by renewable energy production. Literature data on energy consumption and greenhouse gas (GHG) emission by ICEV compared to BEV suffer from a 25% underestimation of ICEV-standardized driving cycle numbers in relation to street conditions so far. Literature data available for BEV, on the other hand, were mostly modeled and based on relatively heavy BEV as well as driving conditions, which do not represent the most useful field of BEV operation. Literature data have been compared with measurements based on the converted Smart, revealing a distinct GHG emissions advantage due to the German electricity net conditions, which can be considerably extended by charging electricity from renewable sources. Life cycle carbon footprint of BEV is reviewed based on literature data with emphasis on lithium-ion batteries. Battery life cycle assessment (LCA) data available in literature, so far, vary significantly by a factor of up to 5.6 depending on LCA methodology approach, but also with respect to the battery chemistry. Carbon footprint over 100,000 km calculated for the converted 10-year-old Smart exhibits a possible reduction of over 80% in comparison to the Smart with internal combustion engine.ConclusionFindings of the article confirm that the electric car can serve as a suitable instrument towards a much more sustainable future in mobility. This is particularly true for small-size BEV, which is underrepresented in LCA literature data so far. While CO2-LCA of BEV seems to be relatively well known apart from the battery, life cycle impact of BEV in categories other than the global warming potential reveals a complex and still incomplete picture. Since technology of the electric car is of limited complexity with the exception of the battery, used cars can also be converted from combustion to electric. This way, it seems possible to reduce CO2-equivalent emissions by 80% (factor 5 efficiency improvement).

Wet deposition of metals to the tropical North and the South Atlantic ocean

Abstract The dominance of wet trace element deposition to the tropical North Atlantic Ocean over dry input is proven by analysis results of rain samples from shipboard sampling. Concentrations of Al, Ca, Cd, Co, Cu, Fe, Mg, Mn, Na, Ni, Pb, Tl and Zn were measured in 9 rain samples from the equatorial Atlantic Ocean and 4 rain samples from the South Atlantic Ocean. The results include some of the first data for trace metal concentrations in South Atlantic precipitation. Elemental concentrations from seawater samples taken in parallel are introduced to allow for an estimation of recycling rates of seasalt components. This revealed a net trace metal flux from the atmosphere into the ocean in the vicinity of the intertropical convergence zone (ITCZ). Recycling rates of Al, Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn ranged from a minimum of 7 × 10−4% (Co) to a maximum of 75% (Al). Higher values were found in the southwest Atlantic. Trace metal concentrations in southwestern Atlantic precipitation also seem to be connected to anthropogenic sources, as implied by enrichment factors relative to the earth crust. Data on trace metal flux by wet deposition are given on an annual scale for the ITCZ, further allowing for an estimation of elemental residence times in surface seawater.

Trace metals in suspended particulate matter of Atlantic Ocean surface water (40 °N to 20 °S)

In this synoptic study the distribution and trace element composition of oceanic suspended particulate matter (SPM) are presented. SPM was extracted from up to 1000 I of surface seawater by a continuous flow technique at 34 transects along the Atlantic Ocean. With an overall average of 27 μg/l, concentrations of SPM ranged from less than 1 μg/l in the southwestern Atlantic to a maximum of 115 μg/l in the open ocean off West Africa. Particulate concentrations of Al, Cd, Cu, Fe, Mn and Pb and distribution of particulate organic carbon (POC) were determined revealing significant and surprising spatial and seasonal variations: although sampling was performed on two cruises at different longitudes and seasons, particulate Al, Fe, Mn and Pb concentrations were very similar. Unlike these four elements, distinct seasonal differences in particulate Cd concentration were found and traced back to biological activity. Clearly distinguished peak concentrations for Al (7.1 nM) and Fe (2.5 nM) were found in the Intertropical Convergence Zone (ITCZ), while maxima for Cd (7.6 pM), Cu (24 pM) and Pb (1.1 pM) were located further north in the subtropics. A significant correlation between POC and all six metals is further reported. SPM investigated in this study was found to consist mainly of phytoplankton. Corresponding dissolved Al, Cd, Cu and Pb concentrations in surface seawater are reported. Comparison with the particulate fraction shows that more than 90% of Cd, Cu and Pb and more than 80% of Al are localized in the dissolved state.