Most heavymetals are highly toxic or Eco toxic properties including cobalt, copper; manganese, molybdenum, andzinc, arsenic, cadmium, lead, mercury, manganese, zinc chromium etc. cannot bedegraded and destroyed because of their solubility in water and hence it getsconsumed by life forms by three pathways via eating food, drinking water, andinhaling air. There are some essential heavymetals like Iron, Chromium Zinc, Cadmium and Cobalt are nutrients that are requiredfor normal body growth of living organism in small amounts.
At specific amountis needed for normal body function; while excessive amounts can be detrimentalto the normal body function of organisms, including kidney damage, creation ofmutations, nervous system and induction of tumors. Heavy metals exist within the natural components ofthe earth’s crust and become concentrated as a result of human causedactivities. Heavy” in conventional usage implies high density and “Metal” inconventional usage refer to the pure element or an alloy of metallic elements.Heavy metal has a high density range from 3.
5g/cm3 to above 7g/cm3 and theatomic weights of heavy metal between 63.5 and 200.6 and specific gravity atleast 5 times more than water. They are usually present in the periodic tableas transition metals but not all the transition metal that have a heavy metal.Some of the f-block elements are also heavymetals and they sometimes called trace elements. The element that are usuallyfound in the water form oxides and such elements are called oxyanions.With the expansion of population and industry, therehas been considered increase in the discharge of excess amount of heavy metalsinto the environment has posed a real challenge facing towards modern world.
The removal of heavy metals from theenvironment is of special concern due to their persistence (Mona Karnib et al.2014). Several methods are used for removing of heavy metal from water likeNano remediation, bioremediation, phytoremediation, chemical precipitation,adsorbents, Nano filtration and reverse osmosis etc.
