Bangladesh's coastal zones face compounding threats from climate change, sea-level rise, and the resulting intensification of salinity intrusion, critically jeopardizing freshwater security, agriculture, and local livelihoods. This study presents a spatial multi-criteria analysis using a Geographic Information System (GIS) integrated with the Analytic Hierarchy Process (AHP) to systematically assess and map the hazard, vulnerability, and exposure dimensions driving flood-induced salinity intrusion risk in Satkhira District. The comprehensive assessment utilized 17 thematic criteria, revealing distinct spatial patterns of susceptibility. The Hazard analysis demonstrated that 35.21% of the total area is classified under the combined High and Very High zones, predominantly concentrated in the south-western and south-eastern coastal areas. The biophysical vulnerability assessment indicated a high degree of intrinsic sensitivity, with 36.59% of the district categorized as very highly vulnerable. Conversely, the Exposure analysis identified a substantial 28.19% of the land as highly and very highly exposed, reflecting the high density of valuable assets even in inland Upazilas. The final composite risk map reveals that 27.95% of the study area is subjected to either high or very high salinity intrusion risk, with the highest risk observed in Satkhira sadar. These empirically derived risk maps and quantitative findings offer crucial, evidence-based insights for policymakers, providing a foundational tool for the design and implementation of targeted adaptation strategies, sustainable land-use planning, and disaster risk reduction programs in vulnerable deltaic environments globally.
This study evaluates the single and combined effects of ivermectin (IVM) and butachlor (BUT) on the biochemical and oxidative stress parameters of Nsukkadrilus mbae. Based on the 166.7 and 9.03mg/kg LC50 values for IVM and BUT respectively, 140 earthworms were randomized into 7 groups viz. (i) normal control, (ii) low ivermectin (IVMLow:8.34mg/kg), (iii) high ivermectin (IVMHigh: 25.02mg/kg), (iv) low butachlor (BUTLow: 0.40mg/kg), (v) high butachlor (BUTHigh:1.35mg/kg), (vi) IVMLow + BUTLow) and (vii) IVMHigh+ BUTHigh) for sublethal 14-days exposure and 7-days recovery. The results indicate that lipid peroxidation, glutathione peroxidase, glutathione reductase, aspartate amino transferase, alkaline amino transferase and alkaline phosphatase increased significantly while catalase, superoxide dismutase, protein and glucose decreased significantly (p < 0.05). There were mixed trends in the recovery patterns after the 7-days withdrawal. The bivariate correlation matrix, principal component analysis and integrated biomarker responses indicate interactions of the measured parameters at different concentrations and time in the earthworm. Sustainable practices that minimize harm to soil dwelling organisms by reducing the use of IVM and BUT is advocated.
Microplastics (MPs) pollution, especially, stormwater runoff from non-point sources is a major source of MPs into surrounding soils and aquatic environment. Numerous studies have investigated MPs occurrence, distribution, sources, morphology, environmental impact, and fate and transport (F&T) modeling, particularly in marine and freshwater ecosystems. However, models for MPs F&T, especially in the surface runoff context, are limited in scope or underexplored. This critical evaluation of hydrodynamic, process-based, mass-balance based, statistical, artificial intelligence (AI) based and hybrid approaches, alongside dedicated watershed hydrological models, including their input data requirements, spatial and temporal resolution, land-use classification, microplastic typology, and software accessibility, to underscore influence on the model predictive reliability. Key findings reveal that existing models lack the representation of MPs as a discrete pollutant entity with density-dependent, and morphology-driven transport behavior. Hydrodynamic models excel in mechanistic fidelity but limit their scope with urban watershed runoff, while hydrological models provide an appropriate framework for watershed dynamics but lack MP specific parameterization. AI and hybrid models show promising options for MPs predictive modeling but require robust calibration and validation datasets. Interconnected components of conceptual, structural, and empirical models are linked but constrained by barriers, hence it continues to limit MPs F&T model development and application. Addressing these challenges require standardized protocols, benchmark datasets, and integrated modeling frameworks. The synthesized information presented in this paper will not only assist in developing future MPs F&T models but also guide urban planners, environmental scientists, and water resource managers in selecting appropriate predictive tools for managing watershed MPs pollution.
Wetlands are critical components of the global carbon cycle, functioning as both carbon sinks and sources depending on environmental conditions. This study assessed short-term variability in sediment carbon storage and its physicochemical controls across five tropical wetlands in southern India. Sediment samples collected in March 2024 and March 2025 were analyzed for pH, macronutrients (N, P, K), bulk density (BD), organic carbon (OC), total organic carbon (TOC), and derived carbon indices, including carbon mass (CM), total mass carbon (TMC), and carbon density (CD). Results indicated consistent increases in OC (0.6–2.4% to 0.7–2.65%) and TOC (1.2–6.2% to 1.5–7.1%), accompanied by increases in CD (1.71–10.69 to 2.18–12.57 kgm⁻²), suggesting enhanced short-term carbon accumulation. Correlation and principal component analyses revealed strong associations among carbon-related variables, while BD and pH contributed to secondary gradients. However, these relationships partly reflect mathematical dependencies among derived indices and should be interpreted with caution. Effect size analysis (Cohen’s d) indicated substantial short-term differences for carbon-related variables (d = 2.04–2.46), along with strong effects for OC and BD, reflecting consistent directional changes across sites. Nitrogen showed a supportive role in organic matter accumulation, whereas phosphorus exhibited limited short-term influence. Slightly acidic conditions (pH 4.2–6.0) were associated with reduced decomposition and enhanced carbon preservation. Despite these findings, the study is constrained by its short temporal scope and the absence of key biogeochemical parameters such as redox potential and greenhouse gas fluxes. Overall, the results provide baseline insights into sediment carbon dynamics and inform future wetland carbon monitoring and management strategies.
The persistence of synthetic plastics in natural environments poses a major ecological challenge due to their resistance to degradation and accumulation in terrestrial and aquatic ecosystems. While conventional mechanical and chemical recycling technologies remain limited, fungi have emerged as promising candidates for sustainable plastic bioremediation through their diverse extracellular enzymatic systems. In this study, we evaluated the laccase-inducing potential and polymer-associated metabolic responses of 36 fungal strains isolated from aquatic environments and decaying plant material from two lakes in northeastern Germany. The study combined enzymatic screening with multiple independent indicators of polymer-associated carbon utilization to identify fungal strains with potential relevance for plastic bioremediation. All strains exhibited hydrolytic enzyme activities, including protease, lipase, and esterase production. Laccase activity in selected strains was monitored over 20 days using ABTS as a substrate, revealing substantial variation among fungal taxa and induction treatments. Trichaptum abietinum, Ganoderma sinense, Trametes hirsuta, and Botrytis cinerea exhibited particularly strong laccase responses, especially when induced with polyurethane (PU), rubber, or guaiacol. Complementary analyses, including dissolved organic carbon (DOC) accumulation, oxygen consumption, CO₂ production, and FTIR spectroscopy, demonstrated significant fungal metabolic interaction with polymer-associated carbon sources. DOC concentrations corresponded to more than 90% of the theoretical carbon content initially supplied as polyurethane, indicating extensive mobilization and transformation of polyurethane-associated carbon. However, direct quantification of polymer degradation and identification of transformation intermediates were beyond the scope of the present study. These findings identify several fungal species as promising candidates for future investigations of fungal-mediated plastic transformation and bioremediation applications.
