Evaluation of Potentially Toxic Elements in Roadside Agricultural Soils Using Pollution Indices and Remediation Potential of Manure and Attapulgite in Wheat Cultivation.

Soil near urban areas may be burdened with numerous environmental pollutants including potentially toxic elements (PTEs). In this context, samples near the highway infrastructure in Larissa, Central Greece were examined for pseudo-total concentrations of Cr, Cu, Zn, Pb and Ni, and enrichment, ecological risk and human risk indices were calculated. Co-variation structure between PTEs and key soil properties was assessed through Principal Component Analysis (PCA). Screening for the pollution status of this area would quantify the possible risk, and therefore whether our subsequent rehabilitation trials would be of use. In this context, the most polluted sample was chosen to undergo a variety of remediation alternatives in a pot experiment, incorporating wheat and manure-attapulgite mixtures. Results showed enrichment of soil mainly with Ni, a low probability (9%) of risk exceedance for children for non-carcinogenic health effects and strong associations between the PTEs, indicating common sources. The greenhouse experiments showed that the application of manure-attapulgite reduced PTE concentrations in soil and wheat plant, with the greatest decrease observed for Pb, Cr and Ni. BCF values indicated strong accumulation of Ni (BCF > 1), while Cr and Cu showed limited uptake. Coefficient of contamination level (CCL) values (<1) for Cr and Cu confirmed reduced plant uptake, whereas Ni, Pb and Zn remained above 1. Taken together, the research shows that the fields chosen here are subjected to significant PTE input from lithogenic and anthropogenic sources, which may even become dangerous for sensitive sub-populations. Experimental cultivation of wheat shows that the combined amendments effectively reduced metal bioavailability and soil-to-plant transfer.