This research presents an in-depth analysis of vegetation dynamics within a protected forest ecosystem, employing advanced remote sensing and GIS methodologies. The study utilizes Sentinel-2 satellite imagery, covering an eight-year period (2017 - 2024), to calculate and interpret key vegetation indices such as NDVI, allowing for a detailed assessment of both seasonal and long-term changes in vegetation health. By integrating high-resolution remote sensing data with local GIS layers, including species distribution, topography, and land use, the research explores the relationships between vegetation indices and environmental factors. Meteorological variables, such as precipitation, temperature, and solar radiation, are also analyzed using data from the ERA5 Land dataset to provide further context for vegetation dynamics. Through the use of spatial analysis and cluster methods, the study identifies correlations between vegetation patterns and variables such as terrain and species composition. Patterns observed in vegetation indices reflect the influence of factors such as slope, elevation, and species composition. The study provides a spatial overview of how these variables interact across the forest landscape, allowing for a more structured interpretation of vegetation change.
This study evaluates the geochemical quality of alluvial sediments from the Slănic River (Buzău County, Romania) in the sector Manasia-Dogari, focusing on heavy-metal pollution indicators, ecological risk, and oil contamination. Nineteen sediment samples were analyzed by ME-MS41L (aqua regia digestion, ICP-MS). The local geochemical background was calculated using the iterative median method ± 2 MAD, and 16 pollution indices were computed. Results indicate good overall sediment quality: PLI = 0.968 (no significant pollution), RI = 65.863 (low ecological risk), and mCd = 0.836. Local PI > 1 was recorded for Cu (max 2.177), Mn (max 1.635), and Cd (max 1.428) in isolated samples. The V/Ni ratio (0.530-0.648, mean 0.570) confirms the absence of petroleum contamination. Sample SL-19 (downstream) shows the highest values for most indices. The study provides a baseline for future monitoring.
Air ionisation is an important indicator of air quality, influenced by meteorological, geological, and topoclimatic factors, and may have implications for human health. The present study analyses the air ionisation regime in six resorts in Romania: four on the Black Sea coast and two in the Carpathian Mountains, during summer conditions characterised by anticyclonic atmospheric conditions. The measurements were aimed at determining the concentrations of negative (n⁻) and positive (n⁺) ions, along with meteorological parameters (temperature, humidity, wind speed and atmospheric pressure). The final goal of the study was to determine the levels of air ionisation by components in mountain and coastal resorts, the differences between the two relief types in terms of air ionisation, and how weather and relief influence these levels. The results obtained highlight significant spatial differences between the coast and the mountains, with higher n⁺ values in mountainous areas and lower air ionisation in coastal resorts. In all six resorts, positive ions predominate over negative ions, with the unipolarity coefficient superunitary, and all n⁻ values are below the threshold of 1000 ions/cm³ considered optimal by studies in the field. In coastal areas, ion concentrations are influenced by sea breeze dynamics and processes specific to the coastal environment, whereas in mountainous areas, differences are associated with geological peculiarities and altitude. From a health genetic perspective, the analysed environments present a moderately favourable character, falling into the clean air category for aeroionization, but without reaching optimal levels of negative ionisation associated with the maximum beneficial effects on well-being.
Critically endangered Danube sturgeons rely on specific hydro-geomorphological conditions—such as deep riverbed pools and exposed hard substrates—for spawning, overwintering, and resting. However, continuous high-resolution riverbed maps across the Lower Danube remain scarce. This study provides a high-resolution bathymetric and substrate assessment of three key sturgeon habitats within the Danube Delta Biosphere Reserve: Bălteni,Nufăru, and Isaccea (Noviodunum) in the Danube Delta Biosphere Reserve. Using a 500 kHz interferometric bathymetric sonar coupled with RTK-GNSS positioning and ADCP velocity profiling, we generated 1 m resolution Digital Terrain Models (DTMs) and mapped benthic substrates via side-scan sonar backscatter segmentation. Deep scour pools driven by bedrock steps were mapped at Bălteni (35 m depth) and Nufăru (30 m depth), both hosting exposed hard-bottom substrates that function primarily as overwintering and resting refugia. In contrast, the Isaccea sector features a 17 m deep pool maintained by high flow turbulence over the submerged masonry of the ancient Roman fortress of Noviodunum, exposing a localized gravel-cobble substrate that acts as an active spawning ground. Our findings demonstrate that critical sturgeon habitats in the Lower Danube are highly localized micro-topographic anomalies, emphasizing the necessity of high-definition hydroacoustic surveys for targeted conservation and environmental impact assessments.
Municipal waste management in Bulgaria is undergoing a transition toward a circular economy, seeking a balance between environmental goals and financial sustainability. This study analyzes the relationship between the dynamics of waste generation and the financial mechanisms for its management (2019–2024) to assess the effectiveness of the “polluter pays” principle. The assessment is based on official national statistics, using quantitative and comparative analyses, together with an analysis of operational and fiscal efficiency ratios. It has been established that a 'decoupling' effect is absent at the national level, as income growth and economic expansion continue to drive an increase in waste generation, reaching 496 kg per capita in 2024 – an indicator calculated based on the total volume of generated municipal waste, without differentiation by source of generation (households, commercial entities, or institutions). Simultaneously, a positive technological shift is observed, characterized by a persistent reduction in direct landfilling and expanded pre-treatment practices. Financially, the sector has transitioned from a deficit to full self-sufficiency, achieving over 110% cost coverage due to fee revenues growing faster than management expenditures. Despite the stability achieved at the macro level, the current charging model based on property valuation creates a structural imbalance – it generates fiscal surpluses but fails to provide sufficient economic incentives to reduce waste at the source, which necessitates the accelerated implementation of “pay-as-you-throw” (PAYT) systems. The obtained results outline a dual profile of the system – financially stable and infrastructurally modernizing, but still not fully oriented toward the prevention of waste generation. The current financial stability remains structurally incomplete without a parallel shift toward a consumption-based charging model that actively incentivizes waste reduction at the source.
