It is known that
vegetation can filter out dust, shoot, smoke and much other fine
particulate matter present in air by process of absorption,
detoxification, accumulation or metabolization. The tree species
possessing higher dust escaping capacity has higher chances of survival
in the polluted areas. The study indicated that evergreen plants with
simple, rough, hairy and fast growing trees are good dust arrestors. The
study suggested a systematic way of selecting plant species on the
basis of their efficiency in dust control.
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Keywords
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| Stone quarry, Dust pollution and dust abatement by trees. |
INTRODUCTION
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| The role of trees in controlling ambient temperature and
rainfall has long been understood. The variation of dust
deposition in different plants is due to the fact that different
plants have acquired different morphological features apart from
those factors like phyllotaxy, leaf shape, plant height, leaf
texture, presence or absence of hairs, stomatal frequency are also
related to the efficiency of dust collecting capacity of plants
(Das et al. 1978) have shown that not only the upper
surface but the lower surface of the leaf also collect significant
amount of dust particle. The study suggested a systematic way of
selecting plant species on the basis of their efficiency in dust
control. |
| Earlier studies have revealed that extent of dust
deposition on plants depends on the morphology structure and
arrangement of leaves (Pattanayak et al. 1994,). It is
known that vegetation can filter out dust, shoot, smoke and many
other fine particulate matter present in air by process of absorption,
detoxification, accumulation or metabolisation (Maiti, 1992). Dust
particulates remain in air for varying lengths of time and get
settled out on various parts of plant, especially on leaf surface,
which affects the vegetation of the area. The extent of impact
depends on the amount of dust deposition. Hence the present study
is an attempt to select the appropriate tree species that could be
recommended for plantation in stone quarry area. The approach has been
that the tree species possessing higher dust escaping capacity has
higher chances of survival in these polluted areas. The
objectives of the present study is |
| - To estimate the amount of deposition of particulate on the surface of leaves of various species. |
| - To study the dust filtering capacity of different species of plants having different leaf shape, physiology etc. |
| - To suggest suitable plant species foe plantation in stone quarry area. |
MATERIALS AND METHODS
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| The leaves of 12 different plant species were collected
from the same place, height and age in the stone crushing area.
Following plant species were selected for the present
investigation. |
| For the present study plant species chosen were of both
evergreen and deciduous types with simple and compound leaves. The
leaves were collected in a polythene bags and washed with
distilled water (Patel et al. 1991). The sampled bags were taken
to laboratory and leaves were washed with 300 ml distilled water
and polythene bags were also washed with 50ml of distilled water
to wash out the dust remaining inside the polythene bags. The dust
was filtered with GF/C filter paper and dried at 70 to 80° C for 3
hours and dried dust was weighed. Individual leaf area in cm2 was calculated by tracing out the leaves on graph paper and results were expressed in g/m2. |
Results
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| The detailed morphological characteristics of the
sampled plant species in the study area are shown in the Table 1.
The dust trapping efficiency of different plant species listed in
ascending order is shown in the Table 2. The investigation
revealed many interesting and vital information on the dust escaping
efficiency of the trees which can be considered highly favorable for
promoting their growth in stone quarry area. The maximum dust
depositions recorded were in Tectona grandis, Ficus
bengalensis, Psidium gaujava, Butea monosperma, Mangifera indica,
Muntingia calabura, Artocarpus heterophyllus etc., which may
be attributed to hairy surface of leaves, horizontal elevation, stiff
petiole and branches etc., which results in less movement of
leaves thus exhibiting lesser chances of falling of accumulated
dust. |
| Earlier studies have revealed that extent of dust
deposition on plant depends on the morphological structure and
arrangement of leaves (Pattanayak et al. 1994) Smooth and flexible leaves like Millingtonia hortensis, Azadiracta indica, Melia rubia do not hold dust to the same degree compared to horizontally arranged leaves of Grevillea robusta, Delonix regia, Anacardium occidentale, Tamarindus indica species bearing stiff, horizontal and elevated leaves with rough and hairy surface which hold large amount of dust particles. |
| Similarly drooping leaves and branches have higher
chances of dropping down dust during disturbance by agents like
wind, animal etc. Free hanging leaves as well as swirling leaves
are the main morphological characteristics of dust escaping
efficiency as in Dalbergia sisso, Eucalyptus globulus, Acacia auriculiformis etc.
Certain species acquire a peculiar type of leaves which are
devoid of leaf damage and hurt. Such modification of leaf surface is
highly favorable in dusty environment like stone quarry. |
Discussion
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| The variation in the deposition of pollutants in
different plant species sampled is due to to the fact that the
different plants have acquired different dust collecting capacity.
Among the species investigated Psidium gaujava, Muntigia calabura, Mangifera indica, Terminalia arjuna
etc., showed highest dust collecting capacity. There are also
other factors responsible for the collection of pollutants on the
leaf surface. The phyllotaxy of leaf of also played important role
in this regard. It has been found of alternatly arranged leaves have
acquired highest dust collecting capacity. this is because in
alternate phyllotaxy there is only one leaf in each node. As a
result these leaves are more exposed to free silica content than
the leaves of cyclic phyllotaxy where two or more leaves present
at each side. |
| Similarly the shape of the leaf is also important. Lanceolate type of the leaf shows highest dust collecting capacity (Terminalia arjuna).
The lowest dust collecting capacity pf Pithacolobium dulse
species can be attributable to its arrangement of leaves. In whorled
phyllotaxy there are more than two leaves present at each node.
There fore each leaf at each node receives lesser amount of
pollutants than one leaf at each internodes. |
Conclusion
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| The study indicated that, plants can be used as
potential device of dust remover in stone quarry area. For dust
abatement purpose the leaves showing evergreen, simpled, rough and
hairy and fast growing trees are suggested. The above findings
suggest that species like Terminalia arjuna, Tabebuia argentia,
Eucalyptus globulus, Muntingia calabura, Ficus bengalensis, mangifera
indica, psidium guajava ect., can be grown in dust polluted areas to reduce the pollution. |
Tables at a glance
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 |
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| Table 1 |
Table 2 |
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References
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- Das,
T.M. and Pattanayak, P. 1977. The nature and pattern of deposition of
air borne particle on leaf surface of plants, Proc.seminor on
Afforestation, Inst. J.of P.H.E. pp. 56-62.
- Jackson, M.L. 1973. The Text book of Soil Chemical Analysis. Prentice-Hall Inc., Engle Wood Cliffs, Jersy.
- Maiti, S.K. 1992. Dust collection capacity of plants growing in coal mining areas. IJEP. 13 (4) : 276-280.
- Tiwari,
T.N. and Patel, M.K. 1993. Effect of cement dust on some plants :
Correlations among foliar dust deposition, chlorophyll content and
calcium content. Ind. J. Envt. Prot. 13 (2) : 93 - 95.
- Patel,
M.K. and Tiwari, T.N. 1991. A study of dust pollution in the Rourkela
industrial complex. Part -I . Ind. J. Proc. 11 : 29 - 31.
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