Preliminary enviromagnetic comparison of the moss, lichen, and filter fabric bags to air pollution monitoring

Abstract

Air quality and anthropogenic air pollutants are usually investigated by passive biomonitoring, which utilizes native species. Active biomonitoring, instead, refers to the use of transplants or bags in areas lacking native species. In Finland, the standardized moss bag technique SFS 5794 is commonly applied in active monitoring but there is still a need for simpler and labor-saving sample material even on the international scale. This article focuses on a preliminary comparison of the usability and collection efficiency of bags made of moss Sphagnum papillosum, lichen Hypogymnia physodes, and filter fabric (Filtrete™) in active biomonitoring of air pollutants around an industrial site in Harjavalta, SW Finland. The samples are analyzed with magnetic methods (i.e. magnetic susceptibility, isothermal remanent magnetization, hysteresis loop and hysteresis parameters) highly suitable as a first-step tool for pollution studies. The results show that the highest magnetic susceptibility of each sample material is measured close to the industrial site. Furthermore, moss bags accumulate more magnetic material than lichen bags which, on the contrary, perform better at further distances. Filtrete™ bags are tested only at 1 km sites indicating a good accumulation capability near the source. Pseudo-single-domain (PSD) magnetite is identified as the main magnetic mineral in all sample materials and good correlations are found between different bag types. To conclude, all three materials effectively accumulate air pollutants and are suitable for air quality studies. The results of this article provide a base for later studies which are needed in order to fully determine a new, efficient, and easy sample material for active monitoring.