環境および分析毒性学

Geochemical and Biological Enrichments with Toxic Metals; Anthropogenic Effects

Abstract

Clifford Qualls, Abdul-Mehdi Ali, Spencer G Lucas, Guido Lombardi and Otto Appenzeller

Historical and scientific data suggest that neurotoxins may have affected human health and consequently the history of Renaissance Europe. During the Anthropocene, the epoch we now live in, huge quantities of neurotoxins such as mercury, lead and manganese are added to the biosphere. Here we searched for proxies in biological materials such as plants and animal products for anthropogenic enrichment with such toxins. To put our results into geological perspective we also searched for such toxins in ancient materials dated to pre-human occupation of the earth. We examined the metal content in putative proxies for enrichment in fossil plants from the early Paleocene (~64 million years old) in New Mexico and from present-day New Mexico and compared this to similar proxies from Peru, a country with a rich mining history, which continues to this day, where neurotoxins ravaged pre-Hispanic settlers and affects present-day miners. We found proxies for metals in the plants and other biological materials. Sixty four million year old plant samples found in New Mexico contained more neurotoxins such as mercury, lead and manganese than samples from present-day New Mexico. Contemporaneous samples from Lima, Peru, had even more neurotoxins than the pre-human samples. Despite such geochemical and human enrichments the stability of systems over geological times was not affected by neurotoxin additions to the biosphere. Though intoxications have been well-documented in historical personages and in contemporaneous epidemics of poisoning, our findings imply that the addition of neurotoxins to the biosphere over geological time periods has, as yet, no discernible influence on human health.