Mercury in blast furnace sludge

Blast furnace sludge (BFS) was analyzed for mercury (Hg) for the first time. The content ranged between 0.006 and 20.8 mg kg–1 (median: 1.63 mg kg–1) for 65 analyzed samples from seven former BFS dumpsites in Europe. Sequential ex-traction procedure on 14 of these samples revealed that Hg was mainly present in immobile fractions (> 90 %). The ecotoxically relevant fractions were not of major significance. Volatilization from BFS (mixed with basic oxygen furnace sludge) was low but significant. Mercury release increased with temperature (15 to 25 °C). However, surprisingly Hg flux at 35 °C was lower than at 25 °C. Nevertheless, BFS should be regarded as potential hazardous waste and Hg source, respectively, as Hg is bioaccumulative and is considered as one of the most important environmental pollutants

Comparative assessment of microplastics in water and sediment of a large European river

Aquatic ecosystems are globally contaminated with microplastics (MP). However, comparative data on MP levels in freshwater systems is still scarce. Therefore, the aim of this study is to quantify MP abundance in water and sediment of the German river Elbe using visual, spectroscopic (Fourier-transform infrared spectroscopy) and thermo analytical (pyrolysis gas chromatography mass spectrometry) methods. Samples from eleven German sites along the German part of the Elbe were collected, both in the water and sediment phase, in order to better understand MP sinks and transport mechanisms. MP concentrations differed between the water and sediment phase. Sediment concentrations (mean: 3,350,000 particles m−3, 125–5000 μm MP) were in average 600,000-fold higher than water concentrations (mean: 5.57 particles m−3, 150–5000 μm MP). The abundance varied between the sampling sites: In sediments, the abundance decreased in the course of the river while in water samples no such clear trend was observed. This may be explained by a barrage retaining sediments and limiting tidal influence in the upstream parts of the river. Particle shape differed site-specifically with one site having exceptionally high quantities of spheres, most probably due to industrial emissions of PS-DVB resin beads. Suspended MP consisted predominantly of polyethylene and polypropylene whereas sediments contained a higher diversity of polymer types. Determined MP concentrations correspond well to previous results from other European rivers. In a global context, MP levels in the Elbe relate to the lower (water) to middle section (sediment) of the global range of MP concentrations determined for rivers worldwide. This highlights that elevated MP levels are not only found in single countries or continents, but that MP pollution is an issue of global concern