Abhishek Sharma

Landslides are among the most significant natural hazards in the Himalayan region of India, causing substantial damage to infrastructure, natural resources, and local communities. This study presents an integrated hydro-geotechnical approach for regional landslide susceptibility assessment by combining statistical susceptibility mapping with slope stability evaluation. The proposed framework considers the influence of key hydrologic factors, including rainfall, drainage density, topographic wetness, and groundwater conditions, together with geotechnical properties to better explain the mechanisms controlling slope failure. Five bivariate statistical models, namely, frequency ratio (FR), information value (IV), weight of evidence (WoE), certainty factor (CF), and Shannon entropy (SE), were applied to produce landslide susceptibility maps. Their performance was evaluated using the area under the curve (AUC) and landslide density index (LDI). Among the evaluated models, SE achieved the highest predictive accuracy ( AUC = 87.17 % ), followed closely by FR (87.06%). The results indicate that steep slopes ( > 30 ° ), weak lithological formations, high drainage density, and groundwater conditions are the main factors controlling landslide occurrence in the study area. Slope stability was further evaluated using laboratory-derived geotechnical parameters and circular failure charts (CFC), providing an independent assessment of slope conditions under different groundwater scenarios. The combined use of statistical modeling, hydrologic factors, and geotechnical verification improves the reliability of landslide susceptibility assessment and provides a practical framework that can be applied in other mountainous regions affected by rainfall-induced landslides.

Heavy Metals (HMs) are persistent, non-biodegradable metallic elements that accumulate into soils due to weathering processes and anthropogenic activities, such as mining, smelting and industrial discharges. They can be classified as essential (Cu, Zn, Ni, Fe, Mn), which are toxic in excessive amounts, and non-essential (Cd, Pb, As, Hg), which are dangerous even in small amounts. HMs affect plant metabolism causing production of Reactive Oxygen Species (ROS), growth inhibition and nutrient deficiency, Arabidopsis thaliana seedlings germination was lowered to 55% and 21% at concentrations of 50 and 100 mg L⁻¹ CdCl₂. Phytochelatins, metallothioneins and vacuole sequestration protect plants, but become ineffective at high concentrations of HMs. Metal-resistant fungi help to cope with stress conditions using mechanisms of biosorption, bioaccumulation, biomineralization, bioleaching and biotransformation, adapted Aspergillus niger managed to leach 78.5% Ni and 82.3% Mo during 30 days, while Penicillium chrysogenum eliminated 63% Cd in soil. Partners of fungi, such as Trichoderma and arbuscular mycorrhizal fungi, regulate production of ROS, activation of MAPKs and ABA/JA/SA/ethylene/auxin signaling pathway and expression of MT, PCS, GST, ABC, NRAMP and HMA genes under control of WRKY, MYB, NAC and bZIP transcription factors. Graphic abstract