SOIL IS ONE OF THE LAND RESOURCES THAT EXIST ALL AROUND HUMAN ENVIRONMENT. SOILS ARE AN UN-PROXIMATE COVER OF EARTH THAT MAY APPLY BY STONES AND SEDIMENTS, IN STAID OR MAY FORM IN TRANSPORT. SOILS HAVE BEEN FORMED BY MINERALS, ORGANIC MATERIALS OF LIVING DEAD, WATER AND AIR. BESIDES NUMEROUS TRAIT THAT SOILS HAVE, THEY KNOWN AS THE ENVIRONMENT CLEANER. SO, IF SOIL GOT TAINT, SUBSEQUENTLY THIS POLLUTION WILL TRANSMIT TO WATER, SOIL AND PLANT. THEREFORE IT HAS A DIRECT RELATION WITH HUMAN HEALTH. SINCE LIVESTOCK FEEDS FROM PLANT AND HUMAN FEEDS FROM LIVESTOCK AND PLANT. HEAVY METALS ARE ELEMENTS WITH ATOMIC WEIGHT 63.54 TO 200.59 AND SPECIAL WEIGHT OF MORE THAN 4.
IT SEEMS THAT PH HAS THE MOST AFFECTED BY THE SOLVENT AND SUSTENANCE OF METALS IN THE SOIL. HIGH PH'S OF SOIL HOLD MORE POWER OF HEAVY CATIONS AND ALSO HAVE LESS SOLVENT. IN INACTIVE PH WHICH MOST SOILS HAVE THIS PH, HEAVY CATIONS EXTREMELY ATTRACT BY CLAY PART OF THE SOIL AND ATTRACTED BY WATERY OXIDES IRON, ALUMINUM AND MANGANESE. THIS ARTICLE IS A REVIEW OF THE DIFFERENT METHODS OF REFINING THE SOILS FROM HEAVY METALS.