BIOMARKERS AS INDICATOR FOR WATER POLLUTION WITH HEAVY METALS IN RIVERS, SEAS AND OCEANS

Water is one of our most important natural resources, and there are many conflictingdemands upon it. Skilful management of our water bodies is required if they are to beused for such diverse purpose...
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BIOMARKERS AS INDICATOR FOR WATER POLLUTION WITH HEAVY METALS IN RIVERS, SEAS AND OCEANS BIOMARKERS AS INDICATOR FOR WATER POLLUTION WITH HEAVY METALS IN RIVERS, SEAS AND OCEANS M.NAGEEB RASHED Faculty of Science, 81528 Aswan, South Valley University, Egypt E-mail mnrashed@hotmail.com Fax 002 097 480 449Water is one of our most important natural resources, and there are many conflictingdemands upon it. Skilful management of our water bodies is required if they are to beused for such diverse purpose as domestic and industrial supply, crop irrigation,transport, recreation , sport and commercial fisheries, power generation and wastedisposal. Water pollution is most commonly associated with the discharge of effluentsfrom sewers or sewage treatment plants, drains and factories to the water body of rivers,seas and marines. In the attempt to define and measure the presence and effects ofpollutants epically the metals in rivers and oceans, the biological markers have attracted agreat deal of interest. The principle behind the biomarker approach is the analysis of anorganism metal content and compared the metal concentration with the background metallevels. In this review, the data were collected from different literatures around the worldin using the aquatic organisms as biological indicator for metal pollution in aquaticsystem.INTRODUCATIONWater Pollution with metalsThe aquatic environment with its water quality is considered the main factor controllingthe state of health and disease in both man and animal. Nowadays, the increasing use ofthe waste chemical and agricultural drainage systems represents the most dangerouschemical pollution. The most important heavy metals from the point of view of waterpollution are Zn, Cu, Pb, Cd, Hg, Ni and Cr. Some of these metals (e.g. Cu, Ni, Cr andZn) are essential trace metals to living organisms, but become toxic at higherconcentrations. Others, such as Pb and Cd have no known biological function but aretoxic elements.Source of pollution with metalsMetals have many sources from which they can flow into the water body, these sourcesare:I Natural Sources: Metals are found throughout the earth, in rocks, soil and introduce into the water body through natural processes, weathering and erosion.II Industrial Sources: Industrial processes, particularly those concerned with the mining and processing of metal ores, the finishing and plating of metals and the manufacture of metal objects. Metallic compounds which are widely used in other industries as pigments in paint and dye manufacture; in the manufacture of leather, 2 rubber, textiles , paint, paper and chromium factories which are built close to water for shipping.III Domestic Wastewater: Domestic wastewater contains substantial quantities of metals. The prevalence of heavy metals in domestic formulations, such as cosmetic or cleansing agents, is frequently overlooked.IV Agricultural Sources: Agricultural discharge contains residual of pesticides and fertilizers which contains metals.V Mine runoff and solid waste disposal areas.VI Atmospheric pollution: Acid rains containing trace metals as well as SPM input to the water body will cause the pollution of water with metals.Biological markers (biomarkers or bioindicators)In the attempt to define and measure the effects and presence of pollutants on aquaticsystem, biomarkers have attracted a great deal of interest. The principle behind thebiomarker approach is the analysis of an organism to their metal contents in order tomonitor the metal excess in their tissues. Various aquatic organisms occur in rivers,lakes, seas and marines potentially useful as biomarkers of metal pollutants, includingfish, shellfish, oyster, mussels, clams, aquatic animals and aquatic plants and algae.FISH AS BIOMARKERFish have been used for many years to indicate whether water are clean or polluted. Fishare excellent biological markers of metals in water.Fish from Lakes: Nasser LakeTilapia nilotica is one of the aquatic organisms affected by heavy metals, so in manycases, Tilapia nilotica was used as metal biological marker in toxicological studies inwhich it was substantiated with the highest sensitivity to toxic effect (Patin, 1984).Rashed (2001a, b) studied Co, Cr, Cu, Fe, Mn, Ni, Sr, Pb, Cd and Zn in different tissuesof fish (Tilapia nilotica) from Nasser lake to assess both the water pollution with thesemetals and the lethal level of these metals in fish. Fish samples were collected from twoKohrs in Nasser Lake ( Kohr Kalabsha and Kohr El-Ramel) .The fish tissues includesmuscle, gill, stomach, intestine , liver, veritable column and scales .The fish ages were 1,1.5 , 2, 2.5 and 3 years. This study resulted in that fish scales exhibited the highest ...