title: Distribution in Portugal of some pollutants in the lichen Parmelia sulcata.
abstract: During the months of July and August 1993 a lichen (Parmelia sulcata Taylor) collection campaign was held in Portugal where samples were obtained from olive tree bark at 228 sites, following a grid of 10 x 10 km along the Atlantic coast and 50 x 50 km in the interior of the country. The samples were analysed by instrumental neutron activation analysis and proton induced X-ray emission techniques. Concentration data patterns for the pollutants As, Cr, Hg, Ni, Pb, S, Sb, Se, and V were obtained for the whole country surface by making use of an extinction rule of 1/r(3), preventing any cut-off distance from being artificially introduced. Some pollution sources were identified: (1) oil-powered plants on the Lisbon-Setúbal axis (V, Ni), (2) coal-power plants in Porto and Sines (S, Se), (3) traffic in the northern area and the Lisbon-Setúbal axis (Pb), (4) a chemical industry south of Porto (Hg, As), and (5) soil influence (Cr, Sb). Arsenic and chromium results largely exceed, in a few areas, the concentrations acceptable to plants, and in a few spots also Hg, Ni, and Pb data.
authors.affiliation: Instituto Tecnológico e Nuclear, E.N. 10, 2685 Sacavém, Portugal. cfreitas@itn1.itn.pt
authors.forename: M C
authors.initials: MC
authors.lastname: Freitas
authors.forename: M A
authors.initials: MA
authors.lastname: Reis
authors.forename: L C
authors.initials: LC
authors.lastname: Alves
authors.forename: H T
authors.initials: HT
authors.lastname: Wolterbeek