Moss (Barbula sp.) as a bioindicator to monitor heavy metal air pollution: Comparison of native moss and moss bag technique

Abstract

Biomonitoring techniques using moss (Barbula sp.) as a bioindicator have been used to examine heavy metal deposition in local areas and around point sources. We sought to determine the efficacy of moss bag technique and native moss method against bulk deposition to determine heavy metal air pollution. Atmospheric heavy metal deposition was determined around the industrial area of Sapugaskanda which includes an oil refinery, an industrial zone and three power plants; Sedawatte which has the influence of Kalanitissa power plant and Dalugama University premises which close to the A1 road. Heavy metals (Pb, Ni, Cu, Cd and Cr) were determined by Atomic Absorption Spectroscopy (AAS) during six months of period from October 2007 to March 2008. Heavy metal concentrations measured in three sampling sites during six months of period is given in μg/g dry weight of moss sample in native moss and moss bag technique. Concentration of heavy metals in bulk collector is expressed in μg/cm2 area of the funnel. Dry weight of moss in unit area was used to bring these results into a common unit. A hypothesis was developed according to the equality of population variance of results in two methods and the corresponding significant levels (α value-probability of making a decision to reject the null hypothesis when the null hypothesis is actually true) were obtained from the F distribution table to compare native moss method and moss bag technique with bulk deposition method. The results indicate that the moss bag technique is most suitable to monitor heavy metal air pollution than the native moss method when compared with the bulk deposition method.