Sources of elements in cedar bark collected near a highway (Japan)

Abstract

The component materials of Japanese cedar bark are estimated for 15 chemical constituents. The bark samples collected near a heavily trafficked highway (100 000 cars day −1) were analyzed for Li, Na, K, Mg, Ca, Al, Fe, Mn, Zn, Cu and Pb by atomic absorption spectrometry, and for V, Cl, Br and I by instrumental neutron activation. The concentration ratios in the barks ranged from 1.9 for iodine to 13.6 for lead, which indicate that the elements with high ratios in the bark are derived from two or more origins. From the relationships between Al and the other elements, three were selected as indicator elements for the anthropogenic and natural component materials of the bark: Al for soil dust, Pb for motor vehicle emission and Cl for native bark. The Pb/Al ratio is used to indicate the pollutant to soil dust ratio in the bark. I show that these three component materials are the sources of elements in the bark, by applying a conventional least-mean-squares method to the chemical composition of the cedar bark with the contents of Cl, Al and Pb as the main variables. The chemical composition of the component materials of the bark was also determined.