Reviews of Environmental Contamination and Toxicology provides concise, critical reviews of timely advances, philosophy and significant areas of accomplished or needed endeavor in the total field of xenobiotics, in any segment of the environment, as well as toxicological implications. Chapter “Natural Purification Through Soils: Risks and Opportunities of Sewage Effluent Reuse in Sub-surface Irrigation” is available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.