Using stable isotopes and major ions to identify recharge characteristics of the Alpine groundwater-flow dominated Triglavska Bistrica River

Triglavska Bistrica is a typical Alpine river in the north-western part of Slovenia. Its recharge area includes some of the highest peaks in the Julian Alps. The hydrogeological conditions and flow of the river depend largely on groundwater exchange between the karstified aquifer in the carbonate rocks and the intergranular aquifer in the glaciofluvial deposits. The average volume of the river flow is up to several m3/s. In this study, water samples from different locations along the river were analysed for stable isotope ratios of oxygen and hydrogen, major ions, and concentration of tritium activity. The correlation of major ions suggests that the recharge area consists of both limestone and dolomite rocks. The δ18O and δ2H values decrease downstream, implying that the average recharge elevation increases. At the downstream sampling site V-5, located approx. 300 m upstream from the confluence of the Sava Dolinka River, the calculated mean recharge altitude is estimated to be 1,996 m.

Land Use and Cover Change in the Industrial Era: A Spatial Analysis of Alpine River Catchments and Fluvial Corridors

Land uses affect flood risks in various ways. The comparative analysis of the historical and current land cover/uses helps to better understand changing flood regimes. Based on historical cadastre maps from 1826 to 1859, the land cover/uses in the Austrian catchments of the rivers Rhine, Salzach and Drava were reconstructed to almost the level of exact plots of land. Catchment-wide analysis reveals a six-fold expansion of settlement areas, a decline of arable land by 69% and a shrinking of the formerly glaciated areas by 73% until 2016. In the Alpine fluvial corridors, i.e. flood-prone areas at the valley floors and valley sides at ca. 300-year floods, settlements even expanded 7.5-fold, severely increasing the potential for flood damages. At the same time, the overall channel area of running waters has been reduced by 40% and 95% the formerly large wetlands have been lost. Overall, the fluvial corridors were truncated by 203 km2 or 14%, thereby reducing flood retention capacity. The concentration of intensive forms of human land uses at lower altitudes, coupled with an upward shift of less intensively used, near-natural forms of land cover, has led to a both spatial and vertical separation of Alpine landscape features over the long term. Warmer temperatures due to climate change are expected to promote the demonstrated upward shifts of Alpine vegetation.

Microplastics Monitoring in Environmental Matrices of an Alpine River originating from Hindu Kush Mountain Range

Microplastics (MPs) are cosmopolitan in distribution and an emerging threat to life and the environment. These particles are not restricted to human-inhabited lands but also found in different mountains and glaciers where the human population is relatively low. These MPs make their way to the river ecosystem from glaciers, rains, and municipal and industrial effluents. The current study was designed to highlight MPs' pollution in water, sediments, and fishes of the Swat River: originating from the Hindu Kush Mountain Range. These samples were collected from eight different sites across the river. The average MPs concentrations were 305.79 ± 289.66 MPs/m 3, 588.29 ± 253.95 MPs/kg, and 12.54 ± 8.02 MPs/individual the water, sediments, and fish samples, respectively. The highest MPs concentrations (753.71 ± 330.08 MPs/m 3 ) in water were recorded near Mingora City, whereas MPs concentrations (834.0 ± 367.21 MPs/kg) were the highest on the same site. Among the selected fish species, the highest number of MPs was observed in Shizothorax plagiostomus. In contrast, the lowest in Wallago attu being 17.08 ± 8.27 Among the selected fish species, the highest number of MPs was observed in Shizothorax plagiostomus, whereas the lowest in Wallago attu being 17.08 ± 8.27 MPs/individual and 5.0 ± 2.36 MPs/individual, respectively. Fibres were the most prevalent MPs in all the matrices representing 80%, 92%, and 85% of the total MPs count in water, sediments, and fish samples. These findings highlighted that the high concentration of MPs prevailing in the river originating from high-altitude freshwater sources and awareness, education, ecotourism, sustainable reduction in plastic use, and strict rules and regulations could be helpful to prevent the anthropogenic menace.