HEAVY METALS FROM SOLİD WASTE AND ITS BİOREMEDİATİON

In most of developing countries, solid wastes are being dumped on land without adopting any acceptable sanitary land filling practices. Precipitation that infiltrates the solid wastes disposed on land mixes with the liquids already trapped in the crevices of the waste and leach compounds from the solid wastes. The leachate thus formed contains dissolved inorganic and organic solutes. In course of time, the leachate formed diffuses into the soil and changes the physico-chemical characteristics of water.Leachate from a solid waste disposal site is generally found to contain major elements like calcium, magnesium, potassium, nitrogen and ammonia, trace metals like cadmium, copper, chromium, nickel, lead and organic compounds like phenols, polyaromatic hydrocarbons, acetone, benzene, toluene, chloroform etc. Uncontrolled heavy metal containing leachate to the environment can be detrimental to humans, animals and plants.This study is a review about impact of leachate charasteristics on water quality and public health. Also, natural treatment methods of heavy metals in aquatic environment is evaluated. The treatment methods include the use of microorganisms, biomass and live plants. Protozoans have been found to be present in and metabolizing leachate effluents contaminated by toxic metal ions such as Cu+2, Hg+2 Ni+2 Pb+2 Zn+2 and Cd+2 and toxic compounds. The long-term survival of protozoa in media containing relatively high concentrations of heavy metal ions shows that these organisms have strategies to tolerate, resist or detoxify organic substances and heavy metals. Heavy metals act as toxic when exceeding the limit tolerated.