POLYCYCLIC AROMATIC HYDROCARBON ACCUMULATION IN URBAN, SUBURBAN, AND RURAL VEGETATION

Polycyclic aromatic hydrocarbons (PAH) partition from the atmosphere t o vegetation, soil, water, and sediment In an effort to quantitate veg etation's ability to scavenge PAH, we collected vegetation samples fro m urban, suburban, and rural locations during the summer and fall of 1 995 and determined PAH burdens (ng/cm(2)) on a mass per total leaf sur face area basis. The total PAH burdens in the rural vegetation samples were, on average, 10 times lower than in the urban samples, confirmin g that atmospheric PAH burdens are higher near presumed source regions . We also compared the individual PAH burden profiles for urban, subur ban, and rural samples. All samples had similar profiles for fluorene, phenanthrene, fluoranthene, and pyrene, while the rural samples were depleted of anthracene, benz[a]anthracene, and several higher molecula r weight PAH. In order to calculate a PAH to vegetation mass balance f or the northeastern region of the United States, we divided this land area into rural, suburban, and urban classifications. We then identifi ed the types of Vegetation in each area and estimated the total leaf s urface area. Using our PAH burdens, we calculated that about 160 t tot al PAH/yr flow from the atmosphere to vegetation. Vegetation in this r egion scavenges about 4% of the total amount of PAH emitted in this ar ea.