Boron, strontium, and barium accumulation in selected plants and loss during leaf litter decomposition in areas influenced by coal strip mining

Abstract

In a 20-year-old abandoned surface coal mining area in eastern Ohio, concentrations of B, Sr, and Ba were determined for plant species commonly found in strip-mined and unstripped habitats. Where significant differences between elemental values of plants from strip-mined and unstripped habitats were observed, species from strip-mined areas exhibited higher values of B and lower values of Sr and Ba.Element loss during the 1st year of leaf litter decomposition was determined for leaves of 10 dominant tree species collected in the study area in late October 1975. Loss of boron was found to be greatest during the 1st year of leaf litter decomposition, followed by that of strontium. Some litter types exhibited accumulation of Ba during litter decomposition, whereas other types exhibited slight losses of Ba after 12 months.Leaching experiments using ovendried leaves and acidified distilled water to simulate rainfall revealed that boron was readily leached from all leaves studied except those of Fraxinus americana. A significant correlation was observed between amounts of B remaining after leaching and amounts remaining after 12 months of litter decomposition, which indicated that B loss during this interval was due to leaching losses. Strontium and barium exhibited little mobility as a result of leaching.Strip mining results in edaphic changes with concomitant increases in plant accumulation of boron. However, rapid losses of boron from decomposing leaf litter result in little accumulation of boron in litter with time.