Flux of Benzo(a)pyrene to the Ground Surface and its Distribution in the Ecosystem

Benzo(a)pyrene (BP) has been investigated in bulk atmospheric deposition, moss, needles of pine and some species of vascular plants. At two remote Lithuanian sites, for 1990-1995 the flux of benzo(a)pyrene from the atmosphere to the ground surface varied between 0.3 to 4.8 μg-2 mo-1. Consequently the territory of Lithuania (65,000 km2) yearly was exposed to 624-2574 kg of carcinogen. The distribution of BP in soil and various vascular plant tissues (Trifolium tepens, Elitrygea repens, Thymus serpyllum) indicates that benzo(a)pyrene is assimilated by flora. The concentration of BP is different in various organs of vascular plants and mostly depends on the degree of soil pollution. More than 300 samples of moss, mostly Hylocomium splendens and Pleurozium schreberi were analyzed for BP. From 3.1 to 896.0 μg kg-1 of BP were measured in the moss samples. The flux of BP to the ground surface correlates well with its concentration in moss. A map of BP flux across Lithuania was created.