Differences in the responses of native and transplanted mosses to atmospheric pollution: a possible role of selenium

Native and transplanted mosses of the species Scleropodium purum were used to study the possible adaptation of the former to atmospheric contamination . A total of seven assays were carried out with transplanted moss exposed a t sites around a thermal power station for 28 and 56 days, and native moss collected from the sites at the same time. Irrigated moss bags were used in order to maintain stable conditions throughout the exposure periods. Deter minations were made of levels of Co, Cr, Cu, K, Ni, Pb, Se and Zn in the mo sses. No significant differences were found, throughout the exposure time s tudied, in metal bioconcentration in the native mosses, whereas in the tran splanted mosses the differences were significant for all metals except Ni. The degree of bioconcentration was higher at the start of the exposure peri od and later became more stable. The high levels of Se found in the native mosses compared to the transplanted mosses indicates a possible mechanism o f adaptation by detoxification. (C) 2000 Elsevier Science Ltd. All rights r eserved.