LAUSR

Some lichen species can provide environmental archives of atmospheric deposition of potentially harmful elements that can be investigated as records of environmental change. The use of lichens for air quality assessment in New Zealand has not been widely explored, despite their widespread application around the world. Due to this lack of attention, there is no lichen species that has been formally validated for use locally as an air pollution biomonitor although some species have been identified as being potentially useful. The most promising of these is Parmotrema reticulatum. This study assessed the performance of the lichen, P. reticulatum, as a biomonitor of elemental air pollutants by examining the extent to which its elemental composition can provide a meaningful pollution source apportionment modeling in Auckland's central business district (CBD). Using the elemental content in transplanted P. reticulatum, principal component analysis, cluster analysis and positive matrix factorisation receptor models, the major elemental air pollutants in Auckland's CBD were determined. Five sources explained 74.4% of the total variance contained in the lichen dataset. These sources represent elemental contributions from motor vehicles, port activities, biomass burning, marine aerosol and roadside dust or crustal matter. Motor vehicles, Auckland port activities, Biomass burning and marine aerosol were found to account for 11.8%, 39.8%, 10.2% and 6.9% of the overall elemental concentrations respectively. Emissions from roadside dust accounted for 5.6% of the overall elemental concentrations in the lichen data. Evidence from this study suggests that P. reticulatum elemental content be used to model pollution sources.