Abstract:
The mosses; resembled as the common ancestor of terrestrial plants, have a better suitability to
monitor atmospheric depositions as they obtain nutrients needed for their vital processes from
both wet and dry deposition and they do not have real roots. The weakly developed cuticle of
the mosses is promoted the trace metal uptake from the atmosphere. Thus, this study aimed
to assess the suitability of inhabitant mosses in Avissawella city area to accumulate airborne
trace metals. Mosses were collected along three transects covering the city area and the reference moss samples were collected from nearby pristine area. All the samples were collected
from tree barks and above 1.5 m from the ground. The collected samples were cleaned, oven
dried, powdered, acid digested, and analyzed for Mn, Fe, Ni, Cu, Zn, Cd and Pb by Atomic
Absorption Spectroscopy. At the each and every step, care was taken to avoid any of metal
contamination from used materials and equipments. The obtained results from two sample t
test implied a significant difference (p value ≤ 0.05) between the mean trace metal concentration in mosses collected from city and from reference area. Corresponding mean trace metal
concentrations (µgg-1) for each trace metal in city and reference area are respectively as; Mn:
6.48 ± 0.47, 2.464 ± 0.14, Fe: 1788 ± 173, 247.9 ± 11, Ni: 10.14 ± 0.47, 5.83 ± 0.24, Cu:
9.30 ± 0.76, 3.764 ± 0.12, Zn: 537 ± 42, 160.4 ± 9.7, Cd: 3.231 ± 0.054, 2.456 ± 0.035, Pb:
65.4 ± 3.9, 24.38 ± .0. Accordingly, the indigenous mosses in the city area have accumulated
more amounts of all the trace metals when comparing with their reference samples. Thus indicate the city air is contaminated with mentioned trace elements and the major causes for the
elevated levels of trace metals in air at city area are the automobile exhausts and the industrial
emissions. Further the ratios of the contamination were calculated and this was used to map the
level of contamination as a spatial distribution patterns with ArcGIS 10.4. Moss biomonitoring
is a reliable method which can be implemented as a continuous biological monitoring method
to evaluate the level of airborne trace metals in urban environs.
