Caxias do Sul hosts the second largest metal-mechanic pole in Brazil, which increases the risk of atmospheric contamination. With the aim of identifying species that might be useful as indicators of atmospheric deposition of metals, 15 species of mosses from an urban and a rural setting were analyzed and compared with specimens deposited at the Herbarium of the Universidade de Caxias do Sul. Metal concentrations (Zn, Ni, Cd, Cr, Cu and Pb) were determined using Atomic Absorption Spectrometry (AAS). The Mann-Whitney test indicated concentrations of Zn, Cu, Pb and Cr that were significantly different between the urban and rural areas. Additionally, Concentrations of Zn, Cd, Cu and Pb were significantly higher in recently collected samples. The species Thuidium tomentosum Besch., Sematophyllum subpinnatum (Brid.) E. Britton, Helicodontium capillare (Hedw.) A. Jaeger, Schlotheimia jamesonii (W.-Arnott) Brid. and Meteorium deppei (Hornsch. ex Müll. Hal.) Mitt. are potential biomonitors of atmospheric metal deposition.
atmospheric pollution; bioindicators; Bryophyta; heavy metals; Rio Grande do Sul
