Validation of Parmotrema reticulatum as a biomonitor of elemental air pollutants in Auckland, New Zealand

This study assesses the effectiveness of the lichen Parmotrema reticulatum as a biomonitor of potentially harmful elements (PHEs) in the atmosphere of Auckland. Samples were collected over a period of 12 months from 21 sampling stations. Once a month, lichens were collected from a ‘clean site’ outside the Auckland urban area and transplanted to 20 sites in the Auckland central business district (CBD). In each occasion, the transplanted lichens were exposed for a period of 1 month at the designated sites. The samples were retrieved for element analysis using inductively coupled plasma mass spectrometry. On the whole, the lichens transplanted to the Auckland CBD sites accumulated significantly higher concentrations of Al, Ca, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Sb, Pb, Th, V and Zn than the reference site. The results suggest that P. reticulatum has the ability to accumulate PHEs and detect changes in air quality.