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Abstract:
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Mangroves are considered to play a significant role in global carbon cycling.
Themangrove forests would fix CO2 by photosynthesis into mangrove lumber and
thus decrease the possibility of a catastrophic series of events - global warming by
atmospheric CO2, melting of the polar ice caps, and inundation of the great coastal
cities of the world. The leaf litter and roots are the main contributors to mangrove
sediments, though algal production and allochthonous detritus can also be trapped
(Kristensen et al, 2008) by mangroves due to their high organic matter content and
reducing nature are excellent metal retainers. Environmental pollution due to metals
is of major concern. This is due to the basic fact that metals are not biodegradable
or perishable the way most organic pollutants are. While most organic toxicants can
be destroyed by combustion and converted into compounds such as C0, C02, SOX,
NOX, metals can't be destroyed. At the most the valance and physical form of
metals may change. Concentration of metals present naturally in air, water and soil
is very low. Metals released into the environment through anthropogenic activities
such as burning of fossils fuels, discharge of industrial effluents, mining, dumping of
sewage etc leads to the development of higher than tolerable or toxic levels of
metals in the environment leading to metal pollution. Of course, a large number of
heavy metals such as Fe, Mn, Cu, Ni, Zn, Co, Cr, Mo, and V are essential to plants
and animals and deficiency of these metals may lead to diseases, but at higher
levels, it would lead to metal toxicity. Almost all industrial processes and urban
activities involve release of at least trace quantities of half a dozen metals in
different forms. Heavy metal pollution in the environment can remain dormant for a
long time and surface with a vengeance. Once an area gets toxified with metals, it
is almost impossible to detoxify it. The symptoms of metal toxicity are often quite
similar to the symptoms of other common diseases such as respiratory problems,
digestive disorders, skin diseases, hypertension, diabetes, jaundice etc making it
all the more difficult to diagnose metal poisoning. For example the Minamata
disease caused by mercury pollution in addition to affecting the nervous system can
disturb liver function and cause diabetes and hypertension. The damage caused by
heavy metals does not end up with the affected person. The harmful effects can be
transferred to the person's progenies. Ironically heavy metal pollution is a direct
offshoot of our increasing ability to mass produce metals and use them in all
spheres of existence. Along with conventional physico- chemical methods, biosystem approachment is also being constantly used for combating metal pollution |