TITLE:
Comparison of Pine Needles and Mosses as Bio-Indicators for Polycyclic Aromatic Hydrocarbons
AUTHORS:
Yoshitaka Oishi
KEYWORDS:
Air Pollution; Cuticle Layer; Environmental Monitoring; Indicator Species; Uptake Mechanism
JOURNAL NAME:
Journal of Environmental Protection,
Vol.4 No.8A,
August
12,
2013
ABSTRACT: Polycyclic aromatic hydrocarbons
(PAHs) are ubiquitous environmental contaminants known to be hazardous to human
health. Pine needles and mosses are useful bio-indicators for assessing PAH
pollutions; however, the differences in their PAH uptake mechanisms have not
been sufficiently discussed. In this study, the properties of pine needles and
mosses as bio-indicators of PAHs were investigated on the basis of differences
in their PAH profiles. Five sets each of pine needle and moss samples were
collected from circular sampling plots and analyzed for 16 PAHs. A comparison
of PAH profiles revealed that the proportion of lower molecular weight PAHs (2 - 3 aromatic rings; LMW PAHs) was significantly
higher in pine needles (78.5% ± 4.8%) than in mosses (35.4% ± 6.8%). In contrast, the proportion of higher molecular weight PAHs (5 - 6 aromatic rings; HMW PAHs) was lower
in pine needles (4.3% ± 2.9%) than in mosses (25.1% ± 3.3%). Further, the combination of PAH isomer ratios showed that PAH
sources between pine needles and mosses were not the same. These differences
were explained by their uptake mechanisms and partly by the absorption of PAHs
from soil particles by mosses. These findings indicate that pine needles are
useful for assessing airborne LMW PAH pollution, whereas mosses can be
integrated indicators for assessing complex HMW PAH pollution of the atmospheric
and soil environments. On the basis of these properties, the usefulness of
these bio-indicators should also be evaluated according to the objective of the
assessment and the areas where they are applied.