In situ chemical stabilization of trace element-contaminated soil – Field demonstrations and barriers to transition from laboratory to the field – A review

The contamination of soil by heavy metals and metalloids is a worldwide problem due to the accumulation of these compounds in the environment, endangering human health, plants, and animals. Heavy metals and metalloids are normally present in nature, but the rise of industrialization has led to concentrations higher than the admissible ones. They are non-biodegradable and toxic, even at very low concentrations. Residues accumulate in living beings and become dangerous every time they are assimilated and stored faster than they are metabolized. Thus, the potentially harmful effects are due to persistence in the environment, bioaccumulation in the organisms, and toxicity. The severity of the effect depends on the type of heavy metal or metalloid. Indeed, some heavy metals (e.g., Mn, Fe, Co, Ni) at very low concentrations are essential for living organisms, while others (e.g., Cd, Pb, and Hg) are nonessential and are toxic even in trace amounts. It is important to monitor the concentration of heavy metals and metalloids in the environment and adopt methods to remove them. For this purpose, various techniques have been developed over the years: physical remediation (e.g., washing, thermal desorption, solidification), chemical remediation (e.g., adsorption, catalysis, precipitation/solubilization, electrokinetic methods), biological remediation (e.g., biodegradation, phytoremediation, bioventing), and combined remediation (e.g., electrokinetic–microbial remediation; washing–microbial degradation). Some of these are well known and used on a large scale, while others are still at the research level. The main evaluation factors for the choice are contaminated site geology, contamination characteristics, cost, feasibility, and sustainability of the applied process, as well as the technology readiness level. This review aims to give a picture of the main techniques of heavy metal removal, also giving elements to assess their potential hazardousness due to their concentrations.

Remediation of Metal/Metalloid-Polluted Soils: A Short Review

Hydrothermal carbonization of spent mushroom compost waste compared against torrefaction and pyrolysis

Phytoremediation of Cd-contaminated farmland soil via various Sedum alfredii-oilseed rape cropping systems: Efficiency comparison and cost-benefit analysis.

Current trends and future prospective in nanoremediation of heavy metals contaminated soils: A way forward towards sustainable agriculture.

Soil heavy metal contamination results in both huge economic loss and severe health problem. Many technologies, such as soil stabilization/solidification, soil excavation, soil washing, chemical extraction and phytoremediation, have been developed to treat soil heavy metal contamination. Among these methods, phytoremediation is usually regarded as a promising, environment-friendly, and cost-effective method. However, little information has been found to support this idea. Hence, in this study, we have conducted a cost-effectiveness analysis of three treatment methods (soil excavation and disposal, soil washing, and phytoextraction) in 16 scenarios of different soil texture, site scale, soil metal, and contamination levels with reviewed literature information. The results have showed that phytoextraction is more cost-effective when dealing with the slightly polluted soils, while soil washing is cost-effective for severely-contaminated scenarios.

Wanying Chen

Papers

Cost-Effectiveness Analysis for Soil Heavy Metal Contamination Treatments