Nowadays, the estimation of volumetric soil water content (θ) through apparent dielectric permittivity (ε_a) is the most widely used method. The purpose of this study is to investigate the effect of the high iron content of two sandy loam soils on estimating their water content using two dielectric sensors. These sensors are the WET sensor operating at 20 MHz and the ML2 sensor operating at 100 MHz. Experiments on specific soil columns, in the laboratory, by mixing different amounts of water in the soils to obtain a range of θ values under constant temperature conditions were conducted. Analysis of the results showed that both sensors, based on manufacturer calibration, led to overestimation of θ. This overestimation is due to the high measured values of ε_a by both sensors used. The WET sensor, operating at a lower frequency and being strongly affected by soil characteristics, showed the greatest overestimation. The difference of ε_a values between the two sensors ranged from 14 to 19 units at the maximum actual soil water content (θ_m). Compared to the Topp equation, the WET sensor measures 2.3 to 2.8 fold higher value of ε_a. From the results, it was shown that the relationship θ_m-ε_a^0.5 remained linear even in the case of these soils with high iron content and the multi-point calibration (CALALL) is a good option where individual calibration is needed.

The combustion of biomass has a neutral atmospheric CO₂ fingerprint, because the overall produced CO₂ emissions are balanced by the CO₂ uptake from the plants during their growth. The current study evaluates the environmental impact of the biomass ash wastes originating from the combustion of olive-kernel residuals for electricity production in accordance with Directive EE/2003. Additionally, the study investigates the potential use of such waste in the restoration of depleted calcareous aggregate quarries in the frame of the circular economy, as a substrate or as a soil amendment. Olive-kernel residual ash, obtained from a 5 MW operating electricity power plant, was mixed with soil and tested for its adequacy for use as a substrate or soil amendment in a depleted calcareous aggregate quarry. The positive effects of the olive-kernel residual bottom ashes in the availability and the mobility of major and trace elements were assessed in both batch and column experiments. The effect of biomass ash in soil amelioration was assessed via pot experiments, by examining the growth of two plant species Cupressus sempervirens (cypress) and Dichondra repens (alfalfa). The environmental characterization of the olive-kernel residual bottom ash indicates that the water-leachable concentrations of controlled elements are, generally, within the acceptable limits for disposal as inert waste in landfills. However, the bottom ash was found to contain significant amounts of K, Ca and Mg, which are macro-nutrients for the growth of plants, serving as a slow-release fertilizer by adding nutrients in the soil. The application of bottom ash in the alkaline soil had a minor positive effect in plant growth while the addition of the ash in the acidic soil exhibited considerable effect in the growth of Dichondra repens and Cupressus sempervirens due to the release of nutrients and to the pH conditioning. Olive-kernel residual bottom ash has been proved to be appropriate as a soil amendment, and as a soil substrate for the restoration of depleted quarries, decreasing the requirement for commercial inorganic fertilizers.

Mediterranean Temporary Ponds (MTPs) constitute priority habitat under the European Union Habitats’ Directive. They are inhabited by rare species and subjected to unstable environmental conditions. Lakes and ponds act as early indicators of climate change, to which high altitude ecosystems are especially vulnerable. This study presents a full dataset of the geo-environmental parameters of such habitats (MTPs) along with their current ecological status for the first time. Furthermore, this paper aims to address the lack of basic geo-environmental background on the network of MTPs of Mt. Oiti concerning their geological, geomorphological, mineralogical and geochemical characteristics along with the pressures received from various activities. The study area is located in a mountainous Natura 2000 site of Central Greece, which hosts four MTPs. Fieldwork and sampling of water and bottom sediments were carried out during dry and wet periods between 2012 and 2014. Electrical Resistivity Tomography measurements identified synforms shaped under the ponds that topography does not always adopt them, mostly due to erosion procedures. The most significant feature, distinguishing those pond waters from any other province water bodies is the extremely low content of all studied ions (including NO₂⁻, NO₃⁻, NH₄⁺, PO₄³⁻, HCO₃⁻, SO₄²⁻, Al, As, B, Ba, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Fe, Ga, Gd, Ge, Hf, Hg, K, La, Li, Mg, Mn, Mo, Na, Ni, P, Rb, S, Sb, Se, Si, Sn, Sr, Ti, U, V, W, Zn, and Zr). MTPs water bodies are of bicarbonate dominant type, and a fresh meteoric water origin is suggested. The main pressures identified were grazing and trampling by vehicles. MTPs of Mt. Oiti were classified according to their ecological status form excellent to medium. Our results can contribute to a better understanding of the mountainous temporary ponds development in the Mediterranean environment.

The COVID-19 pandemic has had a profound impact on the European Union and the United States, with varying waves of severity and divergent progress in vaccination campaigns across regions. To address the short-term costs and potential long-term effects of the crisis, policymakers adopted support measures, particularly fiscal policies. This paper provides an overview of the fiscal support measures implemented, with a focus on the euro area and the United States. It also examines the impact of the pandemic and of support policies on the economies of both regions, as well as the ongoing economic recovery. By analysing the fiscal responses and the macroeconomic developments, this study aims to contribute to a better understanding of the diverse approaches taken by policymakers in combatting the COVID-19 crisis and mitigating its economic consequences.

Acid mine drainage (AMD) environments host complex mineral–water systems that are not well represented by spectral libraries derived solely from pure minerals. We present an open dataset that integrates spectroscopy of natural AMD materials with co-located mineralogical and geochemical measurements from the Kirki (Saint Philippos) mine in NE Greece. The dataset includes: (i) laboratory mineral reflectance spectra spanning 350–15,375 nm (visible–near infrared (VNIR)–shortwave infrared (SWIR)–mid-wave infrared (MWIR)–longwave infrared (LWIR)) for 26 compositionally diverse solid samples; (ii) in situ water VNIR spectra from 337–823 nm collected over AMD-impacted streams and lakes; (iii) co-located field measurements (e.g., temperature, pH, electrical conductivity, turbidity); and (iv) an extensive suite of laboratory analyses for both solids and waters, including mineralogical, major-element, and trace-element data. All spectral and analytical products are provided in a harmonized format, with detailed metadata, instrument specifications, and processing documentation. The dataset is designed to support the development and testing of spectral analysis methods, quantitative retrieval algorithms, and cross-sensor comparisons in AMD settings, and to serve as a high-fidelity analog resource for planetary spectroscopy where sulfate- and Fe-oxide detection and longwave infrared mineral characterization are of interest.