Deciphering the impact of anthropogenic activities on surface sediments of urban ponds in Lucknow city, India

The present study deciphers the impact of anthropogenic inputs on the grain size and mineralogical properties of surface sediments in selected urban ponds in Lucknow city; Lucknow of Uttar Pradesh, India. Due to the partially planned or unplanned development and urbanization, the ponds of this city are struggling for their existence. The surface sediments of these urban ponds are studied under Laser Diffraction Particle Size Analyser (LPSA), Fourier-transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Energy-dispersive X-ray Spectroscopy (EDS) and Scanning Electron Microscopy (SEM), to examine relative mineral abundance, elemental composition and surface morphology. The spatio-temporal observations of Landuse/Landcover (LULC) revealed that the steep urbanization over a period of past 40 years (1985–2025) has engulfed about 84% of urban ponds. The grain size analysis revealed that surface sediments have composition of silt and sand. In addition, the sediment samples are poorly sorted (0.799–1.066), fine skewed (0.011–0.162), and platykurtic in nature. Observed geogenic minerals were primarily consists of quartz, mica, feldspar, clays, whereas, biogenic proportion was consist of silica, calcium carbonates and organic matter. Water inflow in ponds through surface run-off may be held responsible for natural minerals, whereas, decay and decomposition of biomass was found to be the prime source of biogenic components. The composition of surface sediment was found to be influenced by both internal processes and peripheral vegetation. Therefore, geo-environmental management approach integrating controlled catchment run-off, stabilization of marginal vegetation, and periodic sedimentological-mineralogical monitoring is recommended to mitigate anthropogenic alteration and preserve the natural depositional dynamics of urban ponds.