Suchergebnisse

In this work, the concentrations of three rare trace elements, antimony (Sb), selenium (Se), and vanadium (V) were determined in the hydrological cycle and soil of a mountain fir forest. The three elements were significantly enriched in throughfall compared to the bulk deposition. Dry deposits, either in particles or vapor form, are probably the cause of this. It was found that for the enrichment of rain with Sb and Se long range transport played a more important role compared to V. The latter had a significant relation with marine derived ions, a rather unexpected finding. Apart from dry deposition coming from long distances, all elements were enriched with continental material. The concentrations of the three elements in soils were close to the average values reported in literature. In addition, their concentrations in the streamflow water were far below the tolerable drinking water limits set up by the World Health Organization and national authorities.

A monitoring campaign was conducted which collected seven-day composite effluent samples (n=33) from 33 conventional wastewater treatment plants (WWTPs) across Germany to measure the concentrations of linear alkylbenzene sulfonates (LAS) and alkyl ethoxysulfates (AES). In addition, seven-day composite influent samples of four WWTPs were taken and analyzed for the same set of compounds, to determine the removal rates of the aforementioned surfactants during conventional wastewater treatment. This study encompasses the analysis of four LAS homologs (C10–C13) and two AES homologs with each 10 ethoxymers (C12 and C14 with 0-9 ethoxy units). Sample pretreatment was carried out by removing the aqueous phase using a rotational vacuum concentrator and reconstituting the analytes in a defined volume of ultra-pure water and acetonitrile. The identification and quantification of target compounds were performed by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The analytical performance of the methods was validated in tap water and effluent water, obtaining good trueness and precision for both matrices. Based on the estimated average effluent concentrations of individual LAS homologs, the average total LAS concentration in monitored WWTP effluents was 14.4 μg/L. Total AES effluent concentrations were lower compared to LAS, with an average total AES effluent concentration of 0.57 μg/L. No correlation between total LAS and AES effluent concentrations was found. Total LAS influent concentrations averaged at 3,200 μg/L, which translates to an average removal rate of 99.6%. The average total influent concentration of AES was 680 μg/L, indicating an average removal rate greater than 99.9%. Retrospective screening of 1,564 suspect list surfactants and their transformation products (TP) by a second laboratory was performed using ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS). The LAS-byproducts dialkyltetralin sulfonates (DATSs), the metabolites sulfophenyl alkyl carboxylic acids (SPACs) and sulfo-tetralin alkyl carboxylic acids (STACs) reached maximum concentration levels of 19 μg/L, 17 μg/L and 5.3 μg/L, respectively. It was shown that in many cases the sum of concentrations of all LAS-related byproducts and TPs surpassed the concentration of the four precursor LAS homologs (C10 – C13) themselves. High concentrations of up to 7.4 μg/L for 41 polyethylenoglycols (PEGs), the longest homolog series so far reported for PEGs, were detected. All quantified surfactants and their TPs and by-products together accounted for concentrations of up to 82 μg/L in effluent wastewater.