Perspectives on Electrokinetic Remediation of Contaminants of Emerging Concern in Soil

Concerns about soil pollution are growing worldwide. Soil pollution can severely degrade the major ecosystem services provided by soil, presenting a risk to human and environmental health. Today, a new class of compounds is the focus of many scientific publications. Contaminants of emerging concern (CECs) comprise a wide variety of chemicals such as pharmaceuticals and personal care products (PPCPs) and endocrine-disrupting chemicals (EDCs). CECs are prone to accumulate in soil, hinder the food chain, and leach into ground and surface waters, carrying unexpected risks to the environment and human health. Novel electrokinetic (EK) technologies for remediating soils contaminated with CECs are being sought, yet the topic remains largely overlooked. The overall EK efficiency for CECs remediation is based on two primary mechanisms: (i) extracting contaminants from soil by electroosmosis and electromigration, and (ii) destroying CECs with induced electrochemical reactions. Also, as soil is a complex ecosystem, one cannot disregard the contribution of bioremediation processes. Here, EK basic concepts will be presented, targeting their use in the development of in situ approaches that minimize changes in the geotechnical and biological properties of soil. In situ remediation approaches should aim to maintain the soil's ecological balance. Thus, this chapter will focus on the primary EK mechanisms involved in removing CECs from soil and their electro-degradation, giving special attention to EK techniques coupled with bioremediation.