Low molecular mass phenolics in foliage of Betula pubescens Ehrh. in relation to aerial pollution

Correlation between air pollution and concentrations of low molecular mass phenolics (LMMP) was studied in young and mature birch leaves (Betula pubescens Ehrh.) in trees growing at different distances from Harjavalta copper-nickel smelter, SW Finland. Concentrations of low molecular mass phenolics were determined by analytical HPLC. Contents of individual phenolics correlated negatively with the distance from the smelter: for the young leaves, Pearson correlation coefficients ranged from −0.04 to −0.96. However, these coefficients and differences in concentrations of individual compounds in young leaves between the most polluted (0 km from the factory) site and the control (10 km from the factory) site were significant only for 1-O-galloyl-β-D-(2-O-acetyl)-glucopymnose, neochlorogenic acid (trans-5-caffeoylquinic acid), trans-5-p-coumaroylquinic acid and quercetin-3-O-β-D-galactopyranoside. In mature leaves, differences between the control and most polluted area were significant only for two compounds: 1-O-galloyl-β-D-(2-O-acetyl)-glucopyranose and neochlorogenic acid. Accordingly, the air pollution of Harjavalta smelter is a stress factor for birch trees associated with accumulation of low molecular mass phenolics in leaves. We discuss use of phenolics as stress and pollution indicators. air pollution, Betula pubescens, birch, heavy metals, phenolic compounds, pollution indicators.