Integrated Assessment of Potentially Toxic Elements (PTEs) Pollution in Agricultural Soils of North Gondar Zone, Ethiopia: Physicochemical Parameters, Pollution Levels, and Associated Health Risks

Agricultural soil contamination by potentially toxic elements is a global concern due to its impacts on food safety and human health, yet comprehensive assessments remain limited in many regions of Ethiopia. This study provides an integrated assessment of PTE contamination in agricultural soils of the North Gondar Zone, Ethiopia, by evaluating physicochemical properties, pollution levels, and human health risks. Soil parameters, including pH, electrical conductivity, organic carbon, organic matter, moisture content, total nitrogen, and available phosphorus, varied among sampling sites. Soil pH ranged from moderately acidic to near-neutral, indicating variations in soil acidity likely associated with differences in moisture content, organic matter, and land management practices, while electrical conductivity values indicated non-saline conditions suitable for agriculture. Concentrations of PTEs (As, Zn, Cd, Pb, and Hg) were generally within permissible limits established by WHO and FAO. Pollution indices revealed predominantly natural background levels for As, Zn, Cd, and Pb, whereas Hg exhibited moderate to strong contamination, with the Geoaccumulation Index and Contamination Factor identifying Hg as the primary environmental risk element. Non-carcinogenic risk assessment showed that hazard quotients and hazard indices for both adults and children were below 1, indicating negligible health risks. Carcinogenic risk assessment demonstrated that all calculated risks were within the acceptable range (10^-6-10^-4), although children showed higher total cancer risk (TCR) values than adults due to greater exposure intensity and lower body weight. Arsenic was identified as the dominant contributor to carcinogenic risk across all sampling sites. The findings demonstrate that agricultural soils in the study area are generally safe with respect to the investigated PTEs; however, Hg contamination indices indicate a potential environmental concern requiring continued monitoring. Sustainable soil management practices, including effective pH management and liming of strongly acidic soils (pH < 5.5), are recommended to improve soil quality, reduce PTE mobility and bioavailability, and minimize future accumulation of hazardous elements while maintaining agricultural productivity.