Pakistan is an agricultural country and its GDP majorly dependent on agriculture. Since 2005 crop growth and productivity reduced due to rapid industrialization. Due to energy crisis farmers prefer to use waste water as it is easily available. Farmers are unaware of nature of waste water as it is major source of contaminants like heavy metals and other toxicants. Chromium (Cr) is seventh most abundant element in earth crust. In earth crust Cr abundance ranges from 100 to 300 micrograms per gram and soils may also contain 6-3000 micrograms per gram Cr. As a result of human activities worlds annual production of Cr is 107 tons per annum. Cromium is serious air, soil and water pollutant mainly comes from paper industries, paints and dyes, tanning, wood preservatives and catalyst production. Cromium occur natural in the environment in different forms Cr (0), Cr (III) and Cr (VI). Cr (III) and (VI) are unstable while the Cr (VI) is highly mobile and toxic. Workers work in industries come in contact directly with Cr, enters in body dermally, orally and through breathing and can cause renal failure and chronic changes in nervous system along with alimentary canal. It is also a carcinogen and a known mutagen and uncontrolled discharge to environment cause serious threat to environment and human health. Increased concentration of Cr in plant species severely affects biological parameters of plants, ultimately lows down vegetation and cause severe harm to plants. It Cause alterations in growth of enzymes, roots, stem and grains and deleterious effects on physiological processes i.e. photosynthesis and mineral nutrition. There are different technologies such as conventional and advance treatments are commonly used to remove Cr from water system. These technologies involve ion exchange method, reverse osmosis, membrane separation and adsorption. These technologies have disadvantages such as reverse osmosis, during reverse osmosis process it removes all the essential minerals from the water which are required by living organisms during treatment. These technologies also suffer from incomplete removal of metals especially for that metals that are found in waste waters. Some of technologies are accurate but are most expensive to use for research in developing countries. Heavy metals pollution had become a serious issue in deteriorating environment. The effects of heavy metals (Cr) in agriculture, water and whole environment can be controlled by removing it from the system by using hyper-accumulators. Phytoremediation is a most economic and clean up technology and also of great interest from economic point of view. It is renewable technology for the removal of Cr from waste water ponds and from agriculture sites instead of using soil excavation and other methods. Different plants species are capable of accumulating metals from soil and water inside various parts. There are 400 different plant species which belongs to 45 plant families which have ability to hyper-accumulate elements. For low level Cr and high level Cr contamination this is most promising method. Most important aspect is choosing specific phyto-remediator species for a specific level of contamination and for specific location. Phytoremediation using native and wild life species require no any special growth species. As compared to other heavy metals Cr is less adverted, only few plants have been investigated for removal from waste water. There is no comprehensive information on Cr accumulation and tolerance mechanism in plants that is essential to gain information in bioaccumulation process. Natural wild plants grow naturally on the bank of streams, ponds and rivers.
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