Bioindication of Heavy Metals in a Waterfall Outflow Using a Bryophyte Community

Huay Pah Lahd stream in Doi Suthep-Pui National Park, Thailand, is potentially vulnerable to nearby anthropogenic activities. In this study, we determined heavy metal accumulation in bryophyte tissue and their growth substrates. Enrichment factors (EFs) of heavy metals were employed to monitor concentrations in bryophyte tissue. Of eight bryophyte taxa investigated, Scopelophila cataractae showed the highest capacity to accumulate metals in tissue, particularly Fe, Zn, Cd and Cu in protonemata (8,026.7, 1,187.2, 16.9 and 530.1 mg kg-1, respectively). Furthermore, the endangered and rare bryophyte taxa S. cataractae and Porella acutifolia were found intermingled with other urban and common aquatic bryophytes. These taxa might be considered sensitive warning organisms for heavy metal stress in stream ecosystems induced by environmental pollution. Because EFs of all heavy metals were < 2, this suggests that natural processes are the key source of heavy metals; furthermore, the environment of this National Park was identified as being heathy, and an important ecosystem buffer and biodiversity haven.