Arsenic and lead spatial distribution and tissue specific accumulation in soils and cultivated potato of the Sila Massif Southern Italy

Potato ( Solanum tuberosum L.) is one of the world’s most widely consumed staple crops and may contribute to human exposure to potentially toxic elements, as its edible tubers grow in direct contact with soil and can accumulate soil-derived elements. This study investigated the occurrence of arsenic (As) and lead (Pb) in agricultural soils and potato tubers cultivated in the Sila Massif (Calabria, southern Italy), aiming to evaluate soil-to-tuber transfer, compare element distribution between potato flesh and skin, and assess dietary risks associated with potato consumption. A total of 126 agricultural topsoil samples and 45 potato tubers (fresh weight basis) were collected from the study area. As and Pb in soil and potato tissues were determined using ICP-MS, and soil pH was determined potentiometrically. The mean concentrations of As and Pb in soils were 2.85 mg/kg and 31.3 mg/kg, respectively, with predominantly slightly acidic soil conditions (mean pH = 5.74). Both elements showed limited transfer from soil to potato tissues, with transfer factors on the order of 10 −3 . As and Pb concentrations were higher in potato skin than in flesh, with soil-to-skin transfer exceeding soil-to-flesh transfer by 4.5 and 2.8-fold, respectively. Spatial analysis revealed localized enrichments of both elements, likely reflecting the geological characteristics of the Sila Massif, including the weathering of granitoid and metamorphic rocks and localized anthropogenic input. Dietary exposure and associated risk estimates based on potato flesh consumption indicated no appreciable health concerns for adults. However, a relatively lower margin of exposure (MOE = 1.5) for developmental neurotoxicity of Pb was estimated for young children, reflecting their higher vulnerability to dietary exposure. Nevertheless, potatoes may contribute to cumulative dietary exposure, particularly among sensitive population groups, and should be considered in broader dietary risk assessments.