Trends in the Water Chemistry of High Altitude Lakes in Europe

Here we present the chemical trends of seven high altitude lakes, analysed within the AL:PE and MOLAR Projects of the EU (1999) and selected on the basis of the availability of complete and reliable data for the period 1984–1999. The lakes are representative of the Scandinavian Alps, the Cairngorm Mountains in Scotland, the Alps and the Pyrenees. Significant trends were identified for some indicators of acidification, for instance pH and alkalinity, but not all lakes reacted similarly to decreasing depositions of sulphate and base cations. Differences in lake response are discussed in relation to recent variations of atmospheric deposition chemistry and associated changes in climatic conditions. Beside individual variations of the studied lakes, depending, among other things, on altitude and morphology, catchment characteristics and climate trends play a major role for the reaction of high altitude lakes on changes in atmospheric depositions.     

Micro- and mesoplastics in sea surface water from a Northern Adriatic coastal area

Environmental Science and Pollution Research - The presence of microplastics in the sea is a global issue widely studied and discussed in the last years. The whole marine ecosystem is now...     

The role of forest type in the variability of DOC in atmospheric deposition at forest plots in Italy

Dissolved organic carbon (DOC) was studied in atmospheric deposition samples collected on a weekly basis in 2005-2009 at 10 forest plots in Italy. The plots covered a wide range of geographical attributes and were representative of the main forest types in Italy. Both spatial and temporal variations in DOC concentrations and fluxes are discussed, with the aim of identifying the main factors affecting DOC variability. DOC concentration increased from bulk to throughfall and stemflow water samples at all sites, as an effect of leaching from leaves and branches, going from 0.7-1.7 mg C L(-1) in bulk samples to 1.8-15.8 mg C L(-1) in throughfall and 4.2-10.7 mg C L(-1) in stemflow, with striking differences among the various plots. Low concentrations were found in runoff (0.5-2.0 mg C L(-1)), showing that the export of DOC via running waters was limited. The seasonality of DOC in throughfall samples was evident, with the highest concentration in summer when biological activity is at a maximum, and minima in winter due to limited DOC production and leaching. Statistical analysis revealed that DOC had a close relationship with organic and total nitrogen, and with nutrient ions, and a negative correlation with precipitation amount. Forest type proved to be a major factor affecting DOC variability: concentration and, to a lesser extent, fluxes were lower in stands dominated by deciduous species. The character of evergreens, and the size and shape of their leaves and needles, which regulate the interception mechanism of dry deposition, are mainly responsible for this.     

Interference of iron as a coagulant on MIB removal by powdered activated carbon adsorption for low turbidity waters

Powered activated carbon (PAC) is widely used in water treatment plants to minimize odors in drinking water. This study investigated the removal of 2-methylisoborneol (MIB) by PAC adsorption, combined with coagulation using iron as a coagulant. The adsorption and coagulation process were studied through different case scenarios of jar tests. The analysis evaluated the effect of PAC dosing in the liquid phase immediately before or after the coagulant addition. Ferric sulphate was used as the coagulant with dosages from 10 to 30 mg/L, and PAC dosages varied from 10 to 40 mg/L. The highest MIB removal efficiency (about 70%) was achieved without the coagulant addition and with the highest PAC dosage (40 mg/L). Lower MIB removal efficiencies were observed in the presence of coagulant, showing a clear interference of the iron precipitate or coagulant in the adsorption process. The degree of interference of the coagulation process in the MIB removal was proportional to the ratio of ferric hydroxide mass to the PAC mass. For both cases of PAC dosing, upstream and downstream of the coagulant injection point, the MIB removal efficiency was similar. However, MIB removal efficiency was 15% lower when compared with experiments without the coagulant application. This interference in the MIB adsorption occurs potentially because the coagulant coats the surface of the carbon and interferes with the MIB coming in contact with the carbon’s surface and pores. This constraint requires an increase of the PAC dosage to provide the same efficiency observed without coagulation.     

Spiking organic chemicals onto sediments for ecotoxicological analyses: an overview of methods and procedures

Environmental Science and Pollution Research - Laboratory testing with spiked sediments with organic contaminants is a valuable tool for ecotoxicologists to study specific processes such as effects...     

Response of atmospheric deposition and surface water chemistry to the COVID-19 lockdown in an alpine area

Environmental Science and Pollution Research - The effects of the COVID-19 lockdown on deposition and surface water chemistry were investigated in an area south of the Alps. Long-term data provided...