Developing Solutions for Human and Environmental Health Risks Created by Exponentially Increasing Exposures to Lanthanide Metals

John Essigmann, Director, Center for Environmental Health Sciences
Bevin Engelward, Professor of Biological Engineering
Harold Hemond, William E Leonhard Professor of Civil & Environmental Engineering

Year One Report Executive Summary

Our collaborative program combines geochemistry and toxicology to assess potential risks to the environment and human health created by the exponentially increasing use of rare earth elements (REE) that have become essential for technological innovation.The objectives of the geochemical studies are to assess the present and historical concentrations and environmental fluxes of REEs. The Hemond lab has measured lanthanide accumulation in core samples extracted from a rain fed bog in Massachusetts.These analyses, which document REE accumulation over the past 150 years,found the greatest concentrations of REEs in core samples dating to the mid 1980’s, suggesting that peak atmospheric concentrations occurred during this period. Additional environmental samples are being analyzed to determine relevant concentrations and chemical species to investigate in toxicological studies that will permit estimates of potential health risks.  The Essigmann and Engelward labs have examined the potential of several environmentally-prominent REEs to damage human cells in culture. These studies have found that the elements cerium, and neodymium can inhibit cell growth.We have also shown that cerium, europium and lanthanum may damage cellular DNA.The potential to damage DNA is modulated by hydrogen peroxide, a chemical that is produced during inflammation by the innate immune system in humans.This finding suggests that airborne exposures to these elements adsorbed to particulates could exacerbate asthma and other respiratory diseases.

Proposed Work

New technologies that promote environmental sustainability by means of increased energy efficiency or expanded renewable energy production require the use of novel materials. Many elements of the periodic table that were once of mainly scientific interest are now becoming of central importance to society.  We propose to mount a collaborative program combining geochemistry and toxicology to assess potential risks to the environment and human health created by rare-earth elements, which have become widely used in recent years and are essential to maintain technological innovation.  Our research will capitalize on the unique resources represented in the expertise of members of the MIT Center for Environmental Health Sciences (CEHS) in geochemistry and cell and molecular toxicology to characterize adverse effects of lanthanides, in elemental and combined forms in which they occur in the environment, to which humans are exposed.  New or expanded processes of mining, smelting, refining, fabrication, product deployment, and end-of-product-life disposal all call for appropriate evaluation of potential risks to both humans and the environment.  This information is essential for optimizing choices among materials and processes in the quest for economically effective environmental solutions and means to improve sustainability.