Seasonal dependence of the chiral composition of alpha-HCH in coastal deposition at the North Sea.

The environmental pollutant alpha-HCH was analysed in seawater, air and bulk deposition samples from the North Sea. Enantioselective analyses of the sample extracts gave evidence of the change of the direction of net air-water gas transfer of the contaminant in dependence on the season. Due to warmer water surface temperatures during late summer to early autumn the equilibrium of alpha-HCH between air and water is dominated rather by volatilisation than deposition. The volatilisation of non-racemic alpha-HCH, as known to occur from seawater, changes the enantiomeric ratio in air, which is reflected in the observed ratio in rain that passes the air column.

Fast determination of trace elements on aerosol-loaded filters by X-ray fluorescence analysis considering the inhomogeneous elemental distribution.

X-ray fluorescence (XRF) analysis was successfully applied for the determination of Ca, Cu, Fe, Mn, Ni, Pb, V and Zn on aerosol filters with a diameter of 150 mm. Ambient aerosol was collected on quartz-fibre filters by Digitel high-volume samplers. For XRF analysis three small filter pieces with a diameter of 32 mm were cut out of each filter, considering the radial dependence of elemental distribution on the filter. Elemental concentration decreases by 8-10% from the centre to the outer circle for coarse mode elements. Distribution of fine mode elements display only small radial dependence (2-4%). Results of quantitative analysis by XRF were compared with atomic spectrometric methods (GF-AAS, ICP-OES). The good agreement between the methods confirmed the application of XRF spectrometry for routine analysis of filter samples loaded with ambient aerosol.

Online monitoring of aerosols with an energy-dispersive X-ray spectrometer.

A continuously working sampling and analyzing device was developed and tested. It is suitable for monitoring of metals bound to particulate matter in emissions of stack gases. The samples were precipitated on a pure quartz fiber filter tape and analyzed shortly afterwards non-destructively by an energy dispersive X-ray spectrometer (EDXRS). By using this method a wide range of elements with atomic numbers from 19 (K) to 82 (Pb) can be analyzed. New experiments have shown that the novel combined particle sampling and analysis system (X-DUST) could also successfully be used for the monitoring of toxic elements in ambient air.

Stability studies of arsenic, selenium, antimony and tellurium species in water, urine, fish and soil extracts using HPLC/ICP-MS.

The stability of arsenic, selenium, antimony and tellurium species in water and urine (NIST SRM 2670n) as well as in extracts of fish and soil certified reference materials (DORM-2 and NIST SRM 2710) has been investigated. Stability studies were carried out with As(III), As(V), arsenobetaine, monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), phenylarsonic acid (PAA), Se(IV), Se(VI), selenomethionine, Sb(III), Sb(V) and Te(VI). Speciation analysis was performed by on-line coupling of anion exchange high-performance liquid chromatography (HPLC) with inductively coupled plasma mass spectrometry (ICP-MS). Best storage of aqueous mixtures of the examined species was achieved at 3 degrees C whereas at -20 degrees C species transformation especially of selenomethionine and Sb(V) took place and a new selenium species appeared within a period of 30 days. Losses and species transformations during extraction processes were investigated. Extraction of the spiked fish material with methanol/water led to partial conversion of Sb(III), Sb(V) and selenomethionine to two new antimony and one new selenium species. The other arsenic, selenium and tellurium species were almost quantitatively extracted. For soil spiked with MMA, PAA, Se(IV) and Sb(III), recoveries after extraction with water and sulfuric acid (0.01 mol/L) were below 20%.

Comparison of two different approaches to calibrate an energy-dispersive x-ray fluorescence spectrometer for the analysis of aerosol-loaded filters.

The quantitative analysis of aerosol loaded filters by x-ray fluorescence spectroscopy implies the use of calibration curves obtained from synthetic standards. Two preparation methods to obtain these calibration samples are described and compared, showing that matrix and enhancement effects are neglible for membranous filters and that both calibrations lead to acceptable results. Calibration standards produced via an aerosol generator always lead to a greater sensitivity compared to the standard produced with droplets. The filters resist the conditions of replicated measurements.

Production of calibration standards for x-ray fluorescence analysis of aerosol particles precipitated on different filter materials.

Calibration results are presented for a method producing filter standards of two different materials. The first filter type is a membranous filter, the second a quartz fibre filter. Multielement solutions with predetermined elemental concentrations have been produced by an aerosol generator and preciptiated onto the respective filter materials. Additionally, the particle size-distribution in the aerosol generator, depending on the salt concentration in the nebulized solution, is presented.

Substance load in rainwater runoff from different streets in Hamburg.

25 substances were determined in runoff, wet and bulk deposition samples from different sampling sites in Hamburg, (a street in an industrial area, a thoroughfare and a small street in a residential area). The runoff from the industrial road and the main street showed similar pollution levels. The surface water from the industrial area contained higher concentrations of As, whereas the main street showed higher concentrations of Pb, Sb and Zn. The runoff from the residential area was loaded substantially lower. Several elements e.g. Co, Cr, V were found to be almost completely adsorbed to particles, but some more toxical elements e.g. Cd, Cu were found at a high percentage in the soluble phase.