Keywords: Azores, elemental mapping, enrichment factors, INAA, instrumental neutron activation analysis, trace elements, epiphytic lichen, Parmotrema bangii, bark, Japanese cedar, Cryptomeria japonica, atmospheric biomonitors, biomonitoring, air pollution, air quality
Element-enrichment factors in Parmotrema bangii and Cryptomeria japonica of Portuguese islands of the central North Atlantic
Owing to their abundance and ability to accumulate airborne elements, the epiphytic lichen Parmotrema bangii (Vain.) Hale and bark from its phorophyte, the Japanese cedar Cryptomeria japonica (L. fil.) D. Don, were chosen as atmospheric biomonitors and collected at five islands of the Azores archipelago, in the central North Atlantic - Sao Miguel and Santa Maria (eastern group); Terceira, Sao Jorge and Pico (central group). Instrumental Neutron Activation Analysis (INAA) was used to determine 26 trace elements. Lichen thalli, substrate barks and samples of superficial soils were collected at each of the 18 sampling sites, located at different altitudes and distances from the shoreline. Enrichment factors for trace elements in the biomonitors (relative to local soils) were assessed using scandium as a crustal reference. A source-apportionment study was conducted, and pattern maps of elemental contents were prepared to illustrate the major differences in their distribution between the surveyed islands.