Manganese is an essential
trace element which is toxic in high doses. Over the past several decades,
manganese has replaced lead as the anti-knock agent in
gasoline, raising concern about air and road-side contamination with this
element. In addition,
manganese is absorbed by the liver, making specific populations (e.g., pregnant women, infants and children, and patients with
liver disease) susceptible to its toxic effects. Using data from the US Census Bureau, the North Carolina State Center for Health Statistics, and the US Environmental Protection Agency, this ecological study evaluated chronic
liver disease mortality rates in North Carolina's 100 counties. It correlated these rates with county-level demographics as well as on-road and non-road air borne
manganese concentrations. Median income by county was inversely associated with chronic
liver disease mortality, while the logarithmically transformed airborne concentrations of on-road
manganese were positively correlated with county-level chronic
liver disease mortality. Because environmental
manganese near roads is likely to increase over time, these pilot findings potentially have regulatory implications and argue for further research.