Chemical Characterisation of NIST Silicate Glass Certified Reference Material SRM 610 by ICP-MS, TIMS, LIMS, SSMS, INAA, AAS and PIXE

National Institute of Science and Technology (NIST) silicate glass SRM 610 is widely used as a certified reference material for various micro-analytical techniques such as SIMS or laser ablation ICP-MS. SRM 610 has been nominally doped with sixty one trace elements at the 500 μg g⁻¹ level, but certified concentration data exist for only a few of these elements. This study reports concentration data for fifty nine trace elements obtained by ICP-MS, SSMS, LIMS, TIMS, INAA, AAS, and PIXE analyses of two different SRM 610 wafers. Most elements fall within a 10% band around a median value of about 440 μg g⁻¹. The REE concentrations are shown to be constant to 3% (1 σ), thus emphasizing the value of SRM 610 as a reference material for REE analyses.
Comparison of our values with published data suggests that different SRM 610 wafers are, within errors, chemically identical for most elements. Exceptions to this general rule appear to be restricted to elements which were partly lost during the production of the glass, e.g. Ag and Br. On the basis of six independent determinations of Rb concentrations, which are systematically lower by a few percent than the reported NIST value, we argue that the certified Rb concentration may not be representative for all distributed SRM 610 wafers.     

Geomagnetische Tiefentellurik Teil II: Die Streichrichtung der untergrundstrukturen des elektrischen Widerstandes,erschlossen aus geomagnetischen Variationen

Zusammenfassung In Richtung des Streichens großräumiger Leitfähigkeitsän-derungen entsteht durch die Induktion der zeitlich variablen ionosphärischen Ströme eine Stromdrängung im Untergrund. Dadurch werden orts- und periodenabhängigeZ-Variationen erzeugt. Mit Hilfe einfacher Annahmen kann man demzufolge aus den zeitlichen magnetischen Variationen die Streichrichtung horizontaler Leitfähigkeitssprünge bestimmen. Die Methoden dazu werden auch mit Hilfe derssc undsfe-Auswert-ungen fremder Autoren ausführlich geschildert und die angenäherte statistische Eliminierung der ionosphärischenZ-Variationen in mittleren Breiten dargelegt. Die berechneten Richtungen stehen im Einklang mit dem Streichen großräumiger geologischer Formationen. Die Tiefe der anomalen magnetischen Induktionserscheinungen dürfte zwischen wenigen km bis deka-km liegen.

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Summary The anomalous local behaviour of the vertical magnetic time-variations is due to regional abrupt changes of electric specific resistivity in horizontal direction. Such local differences of vertical magnetic variations are very frequent in contrast to previous published papers. Under certain conditions it is possible to determine the direction of the underground structures by the aid of geomagnetic variations. The ratio of the vertical and the horizontal component is a function of the period and of the horizontal resistivity gradient. The ionospheric part of theZ-variations in middle latitudes is small in the case of bays andssc's. It has hardly an influence in a statistical treatment. Examples in northern Germany and south-east Europe show the usefulness of magnetic variations and their local character for the determination of the direction of regional geological structures.

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Mitteilung Nr. 122 des Geomagnetischen Instituts Potsdam.     

Mineralogical and geochemical patterns of urban surface soils, the example of Pforzheim, Germany

This study presents a combined geochemical and mineralogical survey of urban surface soils. Many studies on urban soils are restricted to purely chemical surveys in order to investigate soil pollution caused by anthropogenic activities such as traffic, heating, industrial processing, waste disposal and many more. In environmental studies, chemical elements are often distinguished as lithogenic and anthropogenic elements. As a novel contribution to those studies, the authors combined the analysis of a broad set of chemical elements with the analysis of the main mineralogical phases. The semi-quantification of mineralogical phases supported the assignment of groups of chemical elements to lithogenic or anthropogenic origin. Minerals are important sinks for toxic elements. Thus, knowledge about their distribution in soils is crucial for the assessment of the environmental hazards due to pollution of urban soils. In Pforzheim, surface soils (0–5 cm depth) from various land use types (forest, agriculture, urban green space, settlement areas of various site densities) overlying different geological units (clastic and chemical sediments) were investigated. Urban surface soils of Pforzheim reflect to a considerable degree the mineral and chemical composition of parent rocks. Irrespective of the parent rocks, elevated concentrations of heavy metals (Zn, Cu, Pb, Sn, Ag) were found in soils throughout the whole inner urban settlement area of Pforzheim indicating pollution. These pollutants will tend to accumulate in inner urban surface soils according to the available adsorption capacity, which is normally higher in soils overlying limestone than in soils overlying sandstone. However, inner urban surface soils overlying sandstone show elevated concentrations of carbonates, phyllo-silicates and Fe and elevated pH values compared with forest soils overlying sandstone. Thus, in comparison to forest soils overlying sandstones, inner urban soils overlying sandstone affected by pollution concurrently possess elevated concentrations of mineral phases typically providing relatively high adsorption capacities for heavy metals.