Pesky Metals: Historical Perspective, Advances, and Challenges for Remediation of Problematic Metal Contaminants

Abstract Persistent and problematic toxic metal and metalloid pollutants (in particular, As, Hg, Pb, Cd, and Cr) have long been challenging and expensive remediation targets in contaminated surface and subsurface environments. Since the advent of environmental regulations and cleanup in the late 20th century, much progress has been made to address sites of legacy metal pollution and limit new contamination. Despite this, metal pollution remains a global problem, particularly in soils and sediments, with many large legacy sites inadequately remediated, metal contamination widespread in developed and developing nations, and new pollution occurring from informal and often illegal extraction and recycling processes. In this perspective, we highlight advances and challenges in science and technology, and key economic and social factors, that have influenced remediation of these “pesky” metals over the last ∼50 years. Through this lens, we consider emerging challenges and opportunities associated with legacy and critical metals, climate resilience, and sustainability.