## 1 Introduction  
The growing industrialization of the last two centuries has improved life to a great extent in the countries where it occurred. However, several drawbacks were derived. Among them, many industrial activities gave and have given origin to dramatic environmental impacts on air, soil, and water. Concerning soil, the most frequent contamination factor is represented by heavy metals. These pollutants derive from the metal industry, but also agriculture, mining, and waste disposal. Unlike other contaminants, they can persist in the environment for a long time, and this increases the probability to be distributed through the soil layers and transferred to groundwater, with the consistent risk to enter the food chain by water, crops, vegetables, meat, and fish. Each metallic element has a level of toxicity responsible for health impacts over short, medium, and long times. When the metal concentration is known, the toxicological risk can be assessed by literature correlations, usually based on experimental data. When the risk is considered not acceptable for human health, the request for the reclamation of the polluted sites becomes extremely urgent. The management of a polluted site reclamation is considered one of the most challenging environmental issues to address, as it involves multiple inter-related factors. Several techniques have been developed to remove metals from soil. Traditional soil remediation methods, relying on physical and chemical techniques, have been recently supplemented by those based on biological processes, also called Nature-Based Solutions (NBS). The multifaceted problems linked to soil heavy metal contamination require an integrated approach involving different expertise and proficiency. In this regard, the current Special Issue aims to focus and highlight the features of this multidisciplinary topic, thanks to the contribution of researchers with different backgrounds to combine knowledge from many disciplines. A review [1] summarizes these features, showing the relevance of each. This manuscript also describes the main techniques that can be applied for the remediation of metal-contaminated soils. The study highlights the need for tighter cooperation between research and companies involved in remediation, to publish and disseminate the results from experience on a larger scale than the experimental/pilot one. The first research manuscript presented in the Special Issue checks two methods to consider and assess the risk on human health due to soil ingestion, with a particular focus on bioaccessibility [2]. In this study, [PERSON] and [PERSON] studied the bioaccessible concentration of some metals achieved by two extraction methods, namely, the Unified BARGE Method (UBM) and the Simple Bioaccessibility Extraction Test (SBET). Notwithstanding the lower complexity of the second method, the results were similar, demonstrating that the SBET could be used for screening scopes, while the UBM can be adopted to obtain more accurate data. Then, they used these data to calculate the bioaccessible concentration and the cleanup goal and evidenced the need to include the bioaccessibility into the human health risk assessment (HHRA). The manuscript by [PERSON] et al. [3] presents the results achieved by the electrokinetic removal of heavy metals targeting the remediation of contaminated soils. The experimental runs compared the effect of pH on solubilization and transport of the metallic elements to enhance their removal. EDTA and citric acid were used to change pH. For four metals (Cd, Co, Cu, Zn), the long treatment time (65 days) and high citric acid concentration (0.5 M) resulted in their 70-80% removal, whereas for Cr and Pb, the right operative conditions must be found. As a whole, the results are encouraging for future studies. Among the techniques tested and successfully applied to restore and clean up soils, sorption constitutes a good and cheap solution.