Multi-stress environmental drivers of archaeological deterioration in Al-Fustat, Historic Cairo: integration of hydrochemistry, remote sensing, and urban analysis

Abstract This study investigates the main environmental factors causing deterioration in Al-Fustat archaeological area in Historic Cairo. A multidisciplinary approach was applied, combining field observations, hydrochemical analysis, remote sensing, and GIS techniques. Water samples were collected and analyzed to evaluate groundwater quality, while land use/land cover (LULC) and land surface temperature (LST) changes between 1996 and 2022 were assessed using Landsat data. LULC mapping was based on historical land-use maps, Google Earth Pro imagery, and field observations, while LST was derived from Landsat data using the USGS Collection 2 Level-2 Surface Temperature product. The results show the formation of waterlogged zones affecting archaeological remains. Hydrochemical analysis in 2026 indicates very high salinity levels, dominated by sodium and chloride, with significant nitrate contamination, which may be associated with anthropogenic sources such as wastewater leakage. Total dissolved solids (TDS) ranged from 22,950 to 82,880 mg/L, while nitrate concentrations reached up to 6100 mg/L in the shallow groundwater samples. Remote sensing analysis reveals an increase of 38.5% in urban land accompanied by a reduction of approximately 80% in green areas during the period from 1996 to 2022. The mean LST ( μ ) values increased from 32 °C in 1996 to about 38.54 °C in 2022, with a noticeable increase in urban heat island (UHI) intensity. The study identifies groundwater salinity, elevated temperature, and urban activities as important environmental factors associated with archaeological deterioration. These conditions may promote moisture movement and salt crystallization within building materials, potentially accelerating structural damage. The findings highlight the need for improved drainage, regular monitoring of groundwater levels and quality, and the use of conservation materials compatible with saline and damp conditions to protect archaeological remains.