Biomonitoring of air quality in the Cologne Conurbation using pine needles as a passive sampler - Part II: polycyclic aromatic hydrocarbons (PAH)

Emissions from fossil fuel combustion pose a serious thread to public health and impose the need for an improved monitoring of polycyclic aromatic hydrocarbons (PAH), a major class of persistent organic pollutants. For this purpose, utilization of evergreen conifers offers significant biomonitoring potential. In part I of this series we inspected the load of combustion derived magnetic particles in pine needles from 43 locations of the Cologne Conurbation, Germany; we here report the corresponding PAH concentrations and distribution patterns. Concentrations (dry weight) of summed 3-6-ring PAH range between 51 and 410 ng g(-1) with a median of 123.8 ng g(-1); thus being in agreement with other urban studies. Phenanthrene was the dominating PAH with median concentrations of 47 ng g(-1) followed by fluoranthene and pyrene at 22 and 13 ng g(-1), respectively. The major proportion of PAH was attributed to traffic sources, with minor contribution from power plant, domestic heating, industrial, and vegetation burn emissions. Significant differences between major and minor roads were not observed indicating a thorough mixing of PAH-loaded air masses in the Cologne Conurbation. Needles in inner city parks gave much higher PAH concentrations than those in suburban green areas. Although distribution patterns of PAH were variable a PAH source reconciliation based on isomer compositions is difficult, due to thorough mixing of air masses and associated loss of source specificity. Ambient air monitoring in urban areas based on persistent organic pollutant load of vegetation is a feasible and cost effective way of controlling environmental quality. (C) 2004 Elsevier Ltd. All rights reserved.