Last year, the California ban on lead-based ammunition drew on scientific evidence developed by UC Santa Cruz toxicologists Donald Smith and Myra Finkelstein. With a unique “fingerprinting” technique, they directly linked the ammunition to deadly levels of lead poisoning in California condors.
Although lead gets lots of attention, it isn’t the only metal that Smith worries about. In people, manganese toxicity from contaminated water, soil, or dust is an emerging problem in many countries—including our own.
Essential for our bodies at low levels, excessive amounts of manganese can impair cognitive function and cause conditions similar to Parkinson’s disease.
In two separate NIH-funded studies, Smith documented manganese levels in the body and corresponding changes in neurological behavior: one in children with high environmental exposure; another in experimental animal models exposed to manganese as neonates.
The results of the animal study, described in Environmental Health Perspectives, showed that developmental exposure to manganese causes lasting attention and fine-motor deficits. The deficits in the animals parallel those observed in the study on children.
Smith is now exploring the underlying mechanisms of manganese toxicity in the brain and how medications, such as Ritalin, might mitigate those impacts.