Distribution of mercury in lichens across St. Charles, St. James, and St. John Parishes, Louisiana

Concentrations of mercury in the lichens Ramalina stenospora and Parmotrema praesorediosum were determined using a Bacharach Model 50B analyzer system employing the Environmental Protection Agency (EPA) cold vapor atomic abso rption method. Samples were collected from the limbs of live oak trees in a three-parish area in south-east Louisiana. The highest concentrations dete cted were above 0.8 ppm (mu g/ml) and fell off rapidly with increasing dist ance from possible sources of trace metals. The spatial distribution of mer cury concentrations correlated with predominant wind patterns for the regio n. (C) 2000 Elsevier Science B.V. All rights reserved.