High nitrate and fluoride contamination in groundwater cause a variety of disorders, including methemoglobinemia, teratogenesis, and dental and skeletal fluorosis. The present work assesses the non-carcinogenic health risks posed by nitrate and fluoride in infants, children, and adults using the daily water intake (CDI), hazard quotient (HQ), and non-carcinogenic hazard index (HI). Groundwater samples were collected from 36 wells and boreholes in three central Saudi Arabian study areas for nitrate and fluoride analysis using ionic chromatography and fluoride selective electrode, respectively. Nitrate concentrations varied from 0.70 to 47.00 mg/L. None of the 36 studied boreholes had nitrate levels that exceeded WHO guidelines (50.00 mg/L). Fluoride ranged from 0.63 to 2.00 mg/L, and 30.55% of the fluoride samples (11 out of 36) exceeded the WHO recommendations for acceptable drinking water (1.5 mg/L). The average hazard index (HI) values for adults, children, and infants were 0.99, 2.59, and 2.77, respectively. Water samples surpassed the safety level of 1 for adults, children, and infants at 44.44, 97.22, and 100%, respectively. Accordingly, water samples from Jubailah and a few from Wadi Nisah may expose infants, children, and adults to non-cancer health concerns. Infants and children are more vulnerable to non-carcinogenic health risks than adults, possibly due to their lower body weight. Immediate attention and remedial measures must be implemented to protect residents from the adverse effects of F- in the study area.

Contamination of soil with potentially toxic elements (PTEs) is receiving great attention worldwide due to its apparent toxicity and hazards to local residents. The assessments of soil PTE distribution, sources, and environmental risks are, therefore, the first steps of high-efficiency pollutant degradation and sustainable utilization. The current study used a variety of contamination indicators and multivariate methods to evaluate the environmental risk of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in Al-Ahsa soils in eastern Saudi Arabia. For analysis, 30 surface soil samples were collected from palm fields irrigated with groundwater and treated sewage water. Landsat images of Al-Ahsa indicated an increase in the total vegetative area and the residential area, and a decrease in the bare land area from 1985 to 2021. The average concentrations of PTEs (mg/kg⁻¹) were lower than the maximum admissible concentrations and had the following decreasing order: Zn (54.43) > Cr (28.67) > Ni (14.53) > Cu (10.83) > Pb (5.23) > As (2.27) > Hg (0.35) > Cd (0.26). The enrichment factor (EF) findings confirmed that the Al-Ahsa soil is significantly enriched with Hg, moderately to severely enriched with As, and moderately enriched with Cd. The potential ecological risk index (RI) demonstrates a moderate ecological risk, with only certain parts presenting a high risk. The different PTE levels in agricultural soils may be caused partly by the various qualities of groundwater that originate from various aquifers and sewage-treated water. The results of a multivariate analysis showed that most of the anthropogenic sources of Hg, As, and Cd may come from using a lot of fertilizers and insecticides. Levels of the remaining PTEs indicated natural sources from earth crust materials.

Urban flooding poses a significant problem in arid regions, where unusual rainfall events can lead to disastrous consequences. This study used geographic information systems (GIS) to identify and predict potential flood risk zones in Riyadh City, Saudi Arabia. A comprehensive flood risk map was created by integrating various datasets, including digital elevation models (DEM), lithology, precipitation patterns, slope, and drainage density. Through a weighted overlay analysis, Riyadh was segmented into zones with different levels of flood susceptibility, ranging from low to very high risk. The study area spans 905 km². Of this total area, 32% is at a low risk of flooding, while 31%, 24%, and 12% of the area are at a moderate, high, and very high risk of flooding, respectively. The findings of the study were validated through field surveys conducted before and after recent rainfall events. These validation efforts corroborated the high-risk areas predicted by the model, thereby ensuring the reliability of the map for future urban planning and risk mitigation strategies.

Heavy metal contamination in soil is a global issue threatening human health and ecosystems. Accurate spatial maps of heavy metals (HMs) are vital to mitigating the adverse effects on the ecosystem. This study utilizes GIS and multivariate analysis to evaluate HMs in agricultural soils from Al Ghat Governorate, Saudi Arabia, analyzing Al, As, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn using ICP-AES in 35 soil samples. Methods included contamination factor (CF), enrichment factor (EF), risk index (RI), geoaccumulation index (Igeo), pollution load index (PLI), soil quality guidelines (SQGs), and multivariate analysis. The soils, characterized by sandy texture, low organic matter, and alkalinity due to arid conditions and high calcium carbonate, had the following HM concentrations (mg/kg) in descending order: Fe (11,480) ˃ Al (7786) ˃ Mn (278) ˃ Zn (72.37) ˃ Ni (28.66) ˃ V (21.80) ˃ Cr (19.89) ˃ Co (19.00) ˃ Cu (12.46) ˃ Pb (5.46) ˃ As (2.69). EF, CF, and Igeo suggest natural sources for most HMs, predominantly from the sedimentary sequence, with localized Zn, Pb, Co, Mn, and Cu enrichment linked to mixed natural and agricultural influences. PLI and RI indicated acceptable contamination levels, posing no ecological risk. All samples fell below SQG thresholds for As, Cu, Pb, and Cr, confirming minimal ecological threat. Statistical analysis highlighted sedimentary cover as the primary HM source, with agricultural activities contributing to Co, Cu, Ni, and Pb levels.