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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 OCEANSM.NAGEEB RASHEDFaculty of Science, 81528 Aswan, South Valley University, EgyptE-mail m n r a s h e d @h o t m a il. co m Fax 002 097 480 449Water is one of our most important natural resources, and there are many conflicting demands upon it. Skilful management of our water bodies is required if they are to be used for such diverse purpose as domestic and industrial supply, crop irrigation, transport, recreation , sport and commercial fisheries, power generation and waste disposal. Water pollution is most commonly associated with the discharge of effluents from 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 of pollutants epically the metals in rivers and oceans, the biological markers have attracted a great deal of interest. The principle behind the biomarker approach is the analysis of an organism metal content and compared the metal concentration with the background metal levels. In this review, the data were collected from different literatures around the world in using the aquatic organisms as biological indicator for metal pollution in aquatic system.INTRODUCATIONWater Pollution with metalsThe aquatic environment with its water quality is considered the main factor controlling the state of health and disease in both man and animal. Nowadays, the increasing use of the waste chemical and agricultural drainage systems represents the most dangerous chemical pollution. The most important heavy metals from the point of view of water pollution are Zn, Cu, Pb, Cd, Hg, Ni and Cr. Some of these metals (e.g. Cu, Ni, Cr and Zn) are essential trace metals to living organisms, but become toxic at higher concentrations. Others, such as Pb and Cd have no known biological function but are toxic elements.Source of pollution with metalsMetals have many sources from which they can flow into the water body, these sources are: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, 2rubber, 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 aquatic system, biomarkers have attracted a great deal of interest. The principle behind the biomarker approach is the analysis of an organism to their metal contents in order to monitor the metal excess in their tissues. Various aquatic organisms occur in rivers, lakes, seas and marines potentially useful as biomarkers of metal pollutants, including fish, 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. Fish are 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 many cases, Tilapia nilotica was used as metal biological marker in toxicological studies in which 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 tissues of fish (Tilapia nilotica) from Nasser lake to assess both the water pollution with these metals and the lethal level of these metals in fish. Fish samples were collected from two Kohrs in Nasser Lake ( Kohr Kalabsha and Kohr El-Ramel) .The fish tissues includes muscle, 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 concentrations of Cd, Pb, Co,Cr,Ni and Sr (0.088,0.95,0.29,0.30,0.25 and 3.21 µg/g DW respectively). Whole fish contains the higher concentrations of the studied metals compared to the previous study by Awadallah et al.(1985) in the same fish from Nasser Lake, and this mean the increase in metal pollution in Lake water as the results of man activities (Table 1). This increasing in metal concentration was as the result of increasing pollution loads to the Lake from agricultural wastes, which include chemical pesticide and fertilizers. These agricultural wastes reached the Lake body from the agricultural farms on the beach of the Lake. The source of Pb in the Lake water and fish was resulted 3from gasoline contains Pb from the fishery boats and tour ships travels from Aswan toSudan (Mohamed et al.1990).Table 1. Metal concentrations in Tilapia nilotica and water from Nasser Lake in years1980 to 2000Metals Lake Water (µg//l)1985* 2000***Fish (µg/g)1985** 2000***DifferenceWater Fish(µg//l) (µg/g)CdCo Cr Cu FePb12142167189750.001101852402201420.005ND0.0950.0820.0990.1040.0950.0340.250.290.276.450.332 --43 0.15573 0.10811 0.17167 6.350.004 0.235* Sherief et al. (1980) ** Awadallah et al. (1985) *** Rashed ( 2001a,b)Lake Mariut and Lake EdkuAdham et al. (1999) used fish as bioindicator for assessing metal pollution in Delta Lakes (Lake Maryut and Lake Edku ). Lake Edku is grouped 25 the site highest in metal concentrations. Compared to Lakes Maryut and Edku, the Nile water displayed lower levels of metal contamination. Lillo (1976) reported that bolti from Mariut Lake contained less Fe content compared to Nile bolti fish and concluded that the source was from the factories discharge. El- Nabwi et al. (1987) studied the concentration of Pb in fish, Tilapia nilotica, from Maryut Lake and found that Pb concentration was 0.42 ppm.Fish from River NileRiver Nile is the main source for potable water and as the result of man activities in and on the river body it become loaded by metal pollution. Fish in the River Nile was used as biological marker for the River pollution by metals . Mohamed et al. (1990 ) used Tilapia nilotica fish as a biomarker for the Nile water pollution with metals at the discharge. Point of fertilizer factory with the Nile. Ag,Au,Ca, Cr,Cu, Fe,K,Mg,Mn,Na,Ni,Pb,Sr and Zn were determined in tilapia nilotica fish collected from the Nile area at the point of fertilizer discharge to the Nile and south and north this point. The results revealed that fish near the point of the factory discharge possess the highest levels of metals as the result of pollution with metals.Other study for using fish as biomarker for water pollution with metals was conducted (Khallaf et al., 1994). Two species of fresh water fish (Tilapia nilotica ,named Bolti, and Karmout ) caught from River Nile at Hawamdia and Kafer El-Zayat , at North Egypt and also from governmental fish farms (Abbassa and Barseik) were used to detect 4the presence of industrial wastes especially heavy metals as environmental pollution in the river track and its accumulation in edible fish tissues. The result reveals that heavy metals in different water samples except Cu and Zn were more than the recommended permissible levels (Table2). Iron level in Hawamdia and Kafer-El-Zayat tilapia nilotica samples (63.4 and 54.7 µg/g respectively) was more than its permissible levels, these may be due to the discharge of the adjacent chemical factories that used Fe in their processing. Karmout fish from the same locations ( Kafer El-Zayat and Hawamdia ) had lower concentration of Cu,Zn,Ni,Cd and Pb than bolti, while Fe present in higher concentration in bolti than in Karmout.Comparing the fish metals from Abbassa and Barseik fish farms, where no pollution, with the same fish spices from Hawamdia and Kafer-El-Zayat river Nile, it seems that fish of farms exhibit lower concentration of Cu,Ni,Zn,Fe and Co than those from River Nile. This indicates that the fish especially Bolti was highly responsible for metal pollution.Table 2. Heavy metal concentrations in different samples of water (mg/l) and fish (µg/g)from the River Nile and fish farms (Khallaf et al., 1994)Sites/ spices Cu Zn Ni Cd Fe PbHawamdia (Nile)WaterBoltiKarmout0.262.492.100.135.082.090.043.382.690.030.050.140.2254.74.903.430.0470.17Kafer-El-Zayat(Nile) WaterBoltiKarmout0.160.871.130.153.801.320.164.040.920.070.120.130.3663.98.802.890.050.25Abbassa (Farm) WaterBoltiKarmout0.160.871.130.150.391.170.071.04ND0.010.030.020.2510.4ND1.90.0460.18Barseik (Farm) WaterBoltiKarmout0.240.340.610.121.790.460.132.354.200.060.060.130.275.904.303.810.0480.20Permissible level*WaterFish1205400.01100.010.50.3300.12* Permissible level as recommended by Egyptian Organization for Standardization(1993) 5Fish as Metal Biomarker for Water Pollution in WorldwideArsenic as biomarker for water pollution was assessed by Takatsu and Uchiumi (1998) in which the contents of the metal in the tissues of the fish, Tribolodon hakonsis , from Lake Usoriko, located in Aomori Prefecture, Japan, were examined . It was discovered that large amounts of As were accumulated in the eye tissues. This might be partly related to the fact that the lake water contains a relatively large amount of As. Mercury levels in muscle of some fish species from Dique channel, Colombia was measured to assess the water pollution with Hg (Olivero et al.1997). The highest values of Hg (105 µg/kg) found in fish from the Dique channel were lower than those found in fish species from the Lower Gallego and Cince Rivers in Spain (Raldua and Pedrocchi, 1996). In the Tapajos River, an Amazon water body highly exploited by gold mining activities, the average value for Hg in muscle of Carnivorous fish was 690 µg/kg, almost ten times higher than those found in the Dique channel (Malm et al., 1995). They also concluded that, however the highest Hg concentration did not reach the limits level internationally accepted for considering a fish not acceptable for human consumption (WHO, 1990).Kalfakakon and Akrida-Demertai (2000) reported that Ca,Mg,Fe,Cu,Zn and Pb exhibited bio-accumulation from water to fish. They demonstrate that metal concentrations in fish are higher than in water, which indicates the bio-accumulation. They study on the transfer of Cd,Pb,Cu and Zn through the trophic chain of Ioannina Lake (Pamvotis,Greece) ecosystem and investigate the environmental pollution from heavy metals on the trophic chain of the lake. The concentration of Fe,Zn,Cu and Pb were measured in water, aquatic plants , fish and lake organisms .Aquatic plants show a gradual increase in their concentration in relation to the water and fish ( Table 3 )Table 3. Heavy metal concentrations in water, aquatic plants, fish and organisms fromIoannina LakeItems/Metal conc.Fe Zn Cu PbWater (mg/l)Aquatic plant (µg/g) Fish (µg/g) Organisms (µg/g)6.18.00.610.400.0ND*0.630.580.01ND41250.2ND3.02.13*ND, Not detectedAQUATIC PLANTSAquatic plants in relation to their ability to sequester heavy metals have received extensive interest. This interest has focused primarily on aquatic plants as biomarkers of heavy metal pollution. Aquatic plants provide a viable alternative for metals remediation if proper disposal of spent plants can be employed (Jackson et al., 1994).Aquatic plants from River NileAli and Soltan (1999) used free-floating (Eichhornia crassipes), non-rooted-submerged(Ceratophyllum demersum ) and rooted-submerged (Potamogeton crispus) aquatic plants Metals Items Aswan Mansoura Damieta Ras-El-BarCd Water (mg/l)C. demersum (mg/kg)0.0010.020.0020.050.0030.350.0030.25Cu Water (mg/l)C. demersum (mg/kg)2.0369.50.7863.31.821690.89118Fe Water (mg/l)C. demersum (mg/kg)0.3055270.2945200.3822000.08380Mn Water (mg/l)C. demersum (mg/kg)0.03643140.04230100.09218000.08379Ni Water (mg/l)C. demersum (mg/kg)0.04215.20.05312.10.12946.90.0814.2Pb Water (mg/l)C. demersum (mg/kg)0.00338.20.0187.10.00355.70.0091.20Zn Water (mg/l)C. demersum (mg/kg)0.0951000.1371180.4481600.12867.26for assessing heavy metals(Cd, Cu, Fe, Mn, Pb and Zn) in River Nile water at four main station, Aswan (at south), Mansoura, Damieta and Ras-El-Bar (at North). The results reveal that Ceratophyllum demersum accumulate most of the metls and so, it may be useful for monitoring these metals (Table 4).The increase of Fe concentration in aquatic plants from Aswan is mainly due to thegreat quantity of hematite (Fe2O3) that fall into the Nile during shipping process. AswanNile water contains Fe of 0.30 mg/l higher than in the other stations.Ceratophyllum demersum collected from the River Nile at Aswan exhibited greater concentration of Fe (5527 mg/kg DW) than that detected in the same plant from Mansoura, Dameitta and Ras-El-Bar and also, higher than in the same plant collected from other parts of the world e.g. Ceratophyllum demersum collected from the River Pinios in Greece (Fe,53.8 mg/kg DW , Sawidis et al.,1991) and from Kpong Head pond and Lower Volta River, Ghana (2579 mg/kg DW, Biney,1991).Table 4. Heavy metal concentrations in River Nile water and aquatic plants from four stations along the River Nile (Ali and Soltan, 1999)Aquatic plants from worldwideAquatic plants from worldwide had received extensive interest as biomarkers for water pollution with metals. Gupta and Chandra (1994) found 2.4% Pb was adsorbed in aquatic liverworts when it was exposed to 20 ppb metal solution.Aquatic bryophytes (mosses and liverworts) were used as biomonitors of heavy metals pollution (Mouvet et al., 1993). Aquatic biota, Earthworms (Allolophora molleri) was used as bioindicator for heavy metal pollution in water from Ebro River, Spain. The primary sources of heavy metals in the river are the industrial activities along the basin. The results (Table 5 ) show that mean metal Hg, Pb, Cd,, Cu and Zn in all water samples 7from Ebro River (Banos, Mendavia, Gallur and Eixs ) did not vary significantly from one site to another (Ramos et al.,1999).Table 5. Heavy metals in water (mg/l) and aquatic plants (mg/kg) from different sites inEbro River, SpainSite Hg Pb Cd Cu ZnBanos WENDNA4.5NA0.450.762.200.3599.193.9Mendavia WENDNA3.33NA0.500.911.50.8394.189Gallur W END0.131.7ND0.400.232.282.0911.8484.1Eixs WEND0.840.701.530.160.831.991.0859.6313.13W, Water E, aquatic plantND, not determined NA, not allowedAlgal BioassayToxic heavy metals are available to biota from various sources of industrial effluents. Algae play an important role as removers of some polluting metals from aquatic environment and so as biomarkers for water pollution with heavy metals (Gamila and Naglaa, 1999).Shehata and Lasheen (1981) studied the toxicity effects of some Cd on Nile water algae and recorded the occurrence of Cd in the Nile water at less than 1 ug/l.Heavy metals accumulation by two algal species, Synechococcus leopoliensis (green algae) and Dunaliella salina (blue algae) from pollulated water had been shown their uses as a good bioindicatores (Noaman, 2000). A higher efficiency for different metal accumulation was shown by green algae than the blue one. The order of metal affinity to algal cell surface revealed that Ni was the highest cation taken by both algae at the concentration 2 ppm and 4 ppm followed by Cu. Mercury represents the least one.SEABIRDSSeabirds have been used extensively as monitors of heavy metals. Concentrations of heavy metals are often reported for adult birds but less often for chicks or fledglings. However, chicks have been proposed as particularly useful indicators for both baseline pollution studies and monitoring programs, as they concentrate heavy metals during a specific period of time and from a local and definable foraging area (Walsh, 1990). The Cory’s shearwater, Calonectris diomedea , is a long- lived pelagic seabird found in warm marine waters from temperate to sub-tropical zones of the North Atlantic and Mediterranean (Cramp and Simmons, 1977). High concentrations of heavy metals have been reported in tissues of adult Cory’s shearwater from Mediterranean and Salvage islands which were attributed to accumulation from prey items ( Renzoni et al.,1986). Stewart et al. (1997) used Cory’s shearwater as biomarker for sea water pollution with 8heavy metals from different costal (Salvage, Majorca, Linosa and Crete) Azores, Portugal. The cadmium concentration in kidney were 214.17 ug/g in the Salvage , 42.82 ug/g in Majorca , 106 µg/g in Linosa and 187 µg/g in Crete . Zinc concentrations were similar for adult values recorded in Majorca and Linosa, but lower in the Salvage and Crete.The seabird, Red-billed Gulls Larus novaehollandiae scopulinus , was used for monitoring of Hg levels in the sea from New Zealand (Furness and Lewis, 1990). In this study plumage of Red-billed Gulls was as bioindicator of Hg levels in the sea. Analysis of total Hg in the feather samples showed that Hg levels were independent of sex and age in adults. Mean Hg in fresh weight adult body feathers was 2.4 µg/g. Mercury levels in chick feathers were about 80% of levels in adult feather.AQUATIC MAMMALSMany aquatic mammals were used as a good biomarker of metal pollution in marine and seas water; of these mammals oyster, mussels, clams, barnacles, river otter, wild mink, shrimp, mullus barbatus , mytilus and others.Shrimp, Oyster and CrabsIn recent years heavy metal pollution has increased in coastal water of the Gulf of Mexico mainly in Lagunar-Estuarine ecosystem (Vanegas et al., 1997). These systems are essential environment for shrimp production. Shrimp Juvenile P.setiferus was less sensitive to Cd than other shrimps such as Crangon septemspinosa and Palaemonetes vulagaris. White shrimps were less susceptible to the toxic effect of Zn than Daphina magna and Ceriodaphina dubia ( Magliette et al.,1995).Szefer et al. (1997) used Pacific oyster (Crassostrea gigas ) and crabs, Goetice depressa (de Haan) Grapsidae and Leptodius exaratus (H.Milne Edwards, Xanthidae) as trace metals bioindicators of the East Coast water of Kyusha Island , Japan. The Oyster and craps were collected from three areas of Urashiro , Akamizu and Saganoseki along the east coast of Kyushu.The concentrations of Fe, Cd, Zn, Mn, Cu, Ni, and Pb in oysters from Elcho Island , Northern Territory (Australia) were Fe 13.07-273, Cd 0.29-10.63, Zn 2.39-8.51, Mn0.25-4.84, Cu 0.45-8.76, Ni 0.16-0.59 and Pb 2.59-9.38 µg/g FW. In clam from the samearea Fe 94.8-419, Cd 6-20.3, Zn 1.09-6.28, Mn 2515-6256 ,Cu 0.47-3.18, Ni 1.71-5.64 and Pb 0.45-2.17 µg/g. Manganese in clam was highest , therefore it could be used as a bioindicator of Mn in a tropical environment (Peerzada et al.,1992).Striped dolphinsMany studies have been carried out concerning metal accumulation in dolphins from different areas of the world, various dolphins from Mediterranean Sea (Viale et al.,1978), New Zealand (Koeman et al.,1973), the Japanese costs (Honda et al., 1983; Itano et al.,1984a), Argentina (Marcovecchio et al , 1990), French Atlantic coasts and French Mediterranean coasts (Andra et al., 1991), British Isles (Law et al.,1991), Itslian Mediterranean coasts (Tyrrhenian coasts)(Leonzio et al., 1992), Apulian coasts Species Locality Tissue Hg Pb Cd Cr Fe Cu Zn SourceVariousdolphinsMediterranean seaLiverKidney Various tissue14-6041.20-2.200.1-101.2-2.220.1-2.580-38095-669Viale etal.,1978Delphinus delphisNewZealandLiver 35-72 0.21-1.55 30-40 Koeman etal.,1972Stenellacoeruleoa lbaJapanesecoastsLiverMuscleKindney20.778.76.3258.123.144.511.430.1Honda etal.,1983Stenellacoeruleoa lbaJapanesecoastsLiverKidney20514.7Itano etal.,1984 aTursiopsGephyreu sArgentinaLiverKidney8613.40.828.477.729.5196.293.6Marcovecchio et al.,1990Stenellacoeruleoa lbaFrenchAtlantic coastsLiver 1.2-87 Andre etal.,1991Stenellacoeruleoa lbaBritishIslesLiver 11 0.7 9.7 0.5 11 56 Law etal.,1991Stenellacoeruleoa lbaItalinMediterra nean coasts (Tyrrheni an coasts)LiverMuscle Kindney Brain32436.864.7150.050.660.10.17.330.1844.80.1122546.211466.9Leonzio etal.,1992Stenellacoeruleoa lbaApuliacoasts , southernItalyLiverMuscle Kindney Brain18910.8710.313.91.050.410.440.331.750.047.020.030.030.030.050.033072931901137.730.851.451.1324.657.1315.229.04Cardellicchio et al.,2000Stenellacoeruleoa lbaFrenchMediterra nean coastsLiverKindneyBrain66887.233.3Andre etal.,1991TursiopstruncatusSouthCarolina coastsLiver 0.5-146 0.006-0.2721.17-78.988.8-271Beck etal.,19979(Cardellicchio et al., 2000) and south Carolina coasts (Beck et al., 1993). In these studies, concentrations of Hg in dolphins from the Mediterranean are generally higher than those found in the same species from the Atlantic (Table 6).Table 6. Metal concentrations (µg/g) in dolphins in different locations 10Considering the high mobility of cetaceans, these levels reflect the general contamination of the broad and poorly defined area. In the Mediterranean the highest element concentrations are found in dolphins from French, Tyrrhenian coasts and Apulian coasts. Dolphins from Apulian coasts exhibit high levels of Pb (1.05 µg/g) in liver than from other localities. Mediterranean dolphins have the higher Fe level (80-669µg/g). Dolphins assimilate metals both through water and food. Metal assimilation from water occurs mainly through passive diffusion of the metal as soluble compound (Gaskin,1986).REFERENCES[1] Adham,K.G.;Hasan,I.F.,Taha,N.and Amin,Th.(1999): Impact of hazardous exposure to metals in the Nile and Delta Lakes on the Catfish , Clarias Lazera. Environ. Monit. Asses. 54(1):107-124.[2] Ali,M.M.and Soltan,M.E.(1999): Heavy metals in aquatic macrophytes ,water andhydrosoils from the river Nile,Egypt. J.Union Arab.Biol, Cairo 9(B), 99-115.[3] Andre,J.;Boudou,A.;Ribeyre,F.;Bernhard,M.(1991): Comparative study of mercury accumulation in dolphins (Stenella coeruleoalba) from French Atlantic and Mediterranean coasts. Sci.Total Environ. 104: 191-209.[4] Anil,A.G.;Wagh,A.B.(1988): Accumulation of copper and zinc by Balanus amphitrite in a tropical estuary.Mar.Pollut.Bull.19:177-180.[5] Awdallah R.M.,Mohamed A.E.,Gaber S.A.(1985): Determination of trace elements in fish by instrumental neutron activation analysis. J.Radioanal. Nucl.Chem. Lett.95(3), 145-154.[6] Beck,K.M.;Fair,P.;McFee,W.;Wolf,D.(1993): Heavy metals in livers of BottlenoseDolphins standed along the South Carolina Coast. Mar.Pollt.Bull.,34(9): 59-63.[7] Biney,C.(1991): The distribution of trace metals in Kpong Headpond and Lower Volta River,Ghana.In: N.K.Shastree (ed) Perspective in aquatic ecotoxicology. Narendra Publishing House.Delhi.India.[8] Cardellicchio,N.;Giandomenico,P.;Ragone,P.;Di Leo,A.(2000): Tissue distribution of metals in striped dolphins (Stenella coeruleoalba) from the Apulian coasts, Southern Italy. Marine Environ. research 49:55-66.[9] Cramp,S.;Simmons,K.E.L.(1977): Handbook of the birds of Europe, the Middle Eastand North Africa: The birds of the Western Palearctic Vol.1:136-140.[10] Egyptian Organization for Standardization (1993): Egyptian standard , maximum levels for heavy metal concentrations in food. ES 2360-1993,UDC:546.19:815.Egypt.[11] El-Nabawi, A.;Heinzow,B.and Kiruse,H.(1987): As,Cd,Cu,Pb,Hg and Zn in fish from Alexandria region, Egypt.Bull.Environ.Contam.Toxico.,39,889-897.[12] Furness,R.W.;Lewis,S.A.(1990): Mercury levels in the plumage of Red-billed GullsLarus novaehollandiae scopulinus of known sex and age. Environm.Pollt.63:33-39. [...]... Hg in dolphins from the Mediterranean are generally higher than those found in the same species from the Atlantic (Table 6). Table 6. Metal concentrations (µg/g) in dolphins in different locations 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 m n r a s h e d @h o... (µg/g) 6.1 8.0 0.61 0.40 0.0 ND* 0.63 0.58 0.01 ND 41 25 0.2 ND 3.0 2.13 *ND, Not detected AQUATIC PLANTS Aquatic plants in relation to their ability to sequester heavy metals have received extensive interest. This interest has focused primarily on aquatic plants as biomarkers of heavy metal pollution. Aquatic plants provide a viable alternative for metals remediation if proper disposal of spent plants can be employed (Jackson et al., 1994). Aquatic plants from . markers (biomarkers or bioindicators)In the attempt to define and measure the effects and presence of pollutants on aquatic system, biomarkers. BIOMARKERS AS INDICATOR FOR WATER POLLUTION WITH HEAVY METALS IN RIVERS, SEAS