Elemental pollution and risk assessment of soils and <i>Gundelia tournefortii</i> in a multi-sector industrial zone with a history of agricultural use

The study provides new insights into elemental enrichments in soil and <i>Gundelia tournefortii</i> (<i>GT</i>) parts in a complex land use region where intensive agricultural activities were carried out in the past and 343 industrial facilities from various sectors have been operating for the last 32 years. The levels of crustal elements (aluminum (Al), iron (Fe), potassium (K), sodium (Na), titanium (T)), heavy metals (cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), zinc (Zn)), sulfer (S) and phosphorus (P) were determined in the sample matrices, their possible sources and the health risks associated with their human consumption were investigated. Significant enrichments in Cr, Ni, Pb, and Zn were observed in the soils, with the exceptionally high Pb enrichment (EF: 81.34) being noteworthy. The soil pollution index values (PI:2.06-6.82) confirm significant anthropogenic contamination. Bioconcentration factors (BCF) for Cu, K, Na, Mg, P and S were found to be >1 in all roots and stems, Zn showed high accumulation in all roots and most stems, while Cd, Cr, Pb and Mn accumulated in a more limited number of samples. Principal component analysis (PCA) showed that the elements found in the geochemical composition of the region and those representing agricultural chemicals used throughout the long agricultural history overlap and form clusters that cannot be fully separated, while the analysis of the datasets from <i>GT</i> parts yielded similar results. However, the effects of industrial emissions and solid fuel use were clearly evident in the <i>GT</i> root and stem samples. High Nemerow Compound Pollution Index values (NCPIs) indicated contamination in plant parts. Estimated daily intake (EDI) values for Cu and Mn exceeded the tolerable upper intake level (TUIL) for children in many root and stem samples, while EDI values for Cr, Fe, and Zn also exceeded the limit value in several samples. Risk assessments for non-carcinogenic effects showed that numerous samples surpassed the safety limit for children as a result of elevated levels of Cr, Cu, Pb, Zn, Fe and Mn. Estimates for carcinogenic risk (CR) suggested that Cd and Cr in the majority of samples, along with Ni in some samples, could pose a lifetime cancer risk for children. The results reveal that geogenic influences, as well as pressures from past agricultural production and current industrial and fossil fuel-related pressures, are evident on the region's soils and <i>GT</i> crops. The accumulation of toxic elements in edible plant parts poses a risk to food security, necessitating detailed risk assessments. The findings provide a scientific basis for land-use planning and agricultural management, emphasizing the importance of effective emissions monitoring, agricultural production in areas away from polluting sources, and implementing stricter land-use policies for protecting the environment and public health.