A Multivariate and Geographic-Information-System Approach to Assess Environmental and Health Hazards of Fe, Cr, Zn, Cu, and Pb in Agricultural Soils of Western Saudi Arabia

This study evaluates the environmental and health hazards associated with the presence of Fe, Cr, Zn, Cu, and Pb in agricultural soils from the Makkah region in western Saudi Arabia. Soil samples were collected from 32 farms predominantly cultivating dates and vegetables and analyzed for heavy metals (HMs) using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Multivariate statistical analysis, Geographic Information Systems (GIS), and various contamination indices were employed. The average HM concentrations were arranged in descending order as follows: Fe (35.138 mg/kg), Zn (69.59 mg/kg), Cu (55.13 mg/kg), Cr (47.88 mg/kg), and Pb (6.09 mg/kg). Contamination indices indicated considerable enrichment of Cu and deficient to minimal enrichment for the other HMs, though a few individual samples showed higher enrichment factor (EF) values. Risk assessments revealed a low-level risk associated with HMs in Makkah soils. Multivariate analyses suggested that the HMs primarily originated from natural geological processes, with anthropogenic contributions particularly evident for Cu. Hazard index (HI) values ranged from 0.0003 to 0.0691 for adults and 0.003 to 0.6438 for children, remaining below the threshold of 1.0, which indicates no significant non-carcinogenic risk. Lifetime cancer risk estimates for Pb were below 1 × 10−6, while those for Cr ranged from 1 × 10−6 to 1 × 10−4, indicating tolerable carcinogenic risk levels with a few exceptions for Cr in children. This study is significant as it provides critical baseline data on HM contamination in agricultural soils in the Makkah region, offering insights into natural and anthropogenic contributions to soil pollution. The findings contribute to the broader understanding of environmental risk assessments and serve as a foundation for developing sustainable agricultural practices and targeted mitigation strategies to minimize health risks in regions with similar environmental conditions.