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Akhlaghi, M. and Mahjoor, M.M., 2000. Some histopathological aspects of streptococcosis in cultured rainbow trout (Oncorhynchus mykiss). B Eur Assoc. Fish Pat. 24, 132-136.

Ozyurt, G., Kuley, E., Balikci, E., Kagar, C., Gokdogan, S., Etyemez, M. and Ozogul, F., 2011. Effect of the Icing with Rosemary Extract on the Oxidative Stability and Biogenic Amine Formation in Sardine (Sardinella aurita) During Chilled Storage. Food Bioprocess Technol. DOI 10.1007/s11947-011-0586-7.

Soltani, M., Nikbakht, G., Ebrahimzadeh Moussavi, H. A. and Ahmadzadeh, N., 2008. Epizootic outbreaks of Lactococcosis caused by Lactoccoccus garviae in farmed rainbow trout (Onchorhynchus mykiss) in Iran. Bulletin of the European Association of Fish Pathologists, 28(5), 95-106.

Soltani, M., Ghodratnema, M., Ahari, H., Ebrahimzadeh Mousavi, H.A., Atee, M., Dastmalchi, F. and Rahmanya, J., 2009. The inhibitory effect of silver nanoparticles on the bacterial fish pathogens, and Streptococcus iniae Lactococcus garvieae, Yersinia ruckeri Aeromonas hydrophila. Int.J.Vet.Res. 3,

2: 137-142.

Ghasemi pirbalouti, A., Jahanbazi, P., Enteshari, Sh., Malekpoor, F. and Hamedi, B.,

2010. ANTIMICROBIAL ACTIVITY OF SOME IRANIAN MEDICINAL

PLANTS. Arch. Biol. Sci., Belgrade, 62 (3), 633-642.

Shoemaker, C.A., Klesius, P.H. and Evans, J.J., 2001. Prevalence of Streptococcus iniae in tilapia, hybrid striped bass, and channel catfish on commercial fish farms in the United States. AJVR, Vol 62, No. 2.

Assignment of Concentration of heavy metal (Cr, Zn, Cd, Pb) in sediments of Gorgan Bay and South East the Caspian Sea (Golestan Province- Iran) 2010-2011

Mahmood Saghali15*, Rauf Baqraf2, S. Abbas Hosseini3, RahmanPatymar3, ParisaNejatkhahManav4 and Bahador Moghimi Tilemi6

1 National Academy of Sciences of Azerbaijan, Baku, Azerbaijan

2Assistant of Ecology of Azerbaijan Oil Company. Baku, Azerbaijan

3Faculty of fisheries and environment, Gorgan University of Agricultural Sciences and

Natural Resources, Gorgan, Iran, 4Associated professor of Marine Biology Department, Islamic Azad University, North

Tehran Branch. Iran 5Golestan fisheries organization, Gorgan, Iran

6ms student of Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran,

* Corresponding author: M. Saghali, m_saghali18@yahoo.com

Abstract

Heavy metals have been studiedafter their entry into water and absorption and accumulation in sediments and fish muscles in the Gorgan Bay and South East the Caspian Sea for 1 year from January1998 until end of year. The aim of this study is the comparison and analysis of heavy metals in sediment of economical importance in eastern coast of the Caspian Sea and Gorgan Bay. In this study for achievement to this goal had been measured concentrations of heavy metals Lead (Pb), Cadmium (Cd), Zinc (Zn) and Chrome (Cr) from sea bed layers and for this purpose had been utilized an Atomic Absorption Apparatus and then analyzed all of data with Analysis of Variance (ANOVA) Technique in.. software. The results show that the highest level of metals Maximum concentrations of these elements in sediments were observed in station 2 (1976+13) , in station 4 (1397+11), in station 5(415+8), in station 6(715+8) ug/kg in that order. Key words: Heavy Metals - Sediment- Gorgan Bay - Caspian Sea

Coastal areas reflect the processes of oceanic, atmospheric and underground systems. Coastal habitats are naturally affected by human activity and the environmental components of such habitats may be directly or indirectly affected by such activities (Brown and Mclachan,1995). Industrial developments have had advantages but have also caused many problems including major pollution of the seas which has caused environmental degradation and has threatened marine life (AminiRanjbar and Colleagues 1384). Human activity may increase concentration of heavy metals in coastal sediments and at the same time areas of high rural and industrial activity will lead to increase of such sediments in such areas creating high concentrations of pollutants (Luoma, 1983), (Savvdeset, at, 1995).Bealsact as transfer environments for active biogeochemicals. Heavy metals show strong reaction to particles and therefore the presence and destiny of soluble metals is dependent on the reaction of floating organic and nonorganic metal solutions. The total concentration of many types of organic and nonorganic metals in sea water is dependent on chelating (Abdul-wahab and Jupp, 2009).Contamination of sediment problems leads to serious environmental problems and serves as a platform for contaminants that can persist for long periods of time (Savvides, et al, 1995). Marine animals can accumulate metals through sea water, suspended particles, sediments and food chains (Luoma, 1983). Permanent contaminants such as metals may be transferred to higher levels in the food chain through environmental expansion. The levels of these contaminants, due to environmental socialization of species, are generally much higher in marine physique than the surroundings. As many of these species climb the food chain to become food for man, awareness of this aspect is vital. Coastal and beal areas generally turn into collection points for many types of contaminants including heavy metals (kasuba and Rozgaj,2000 ; Suzuki et al, 2001,Lam et al.,1997). The most common heavy metals in marine systems are Lead (Pb), Cadmium (Cd), Zinc (Zn) and Chrome (Cr). These elements are poisonous to organisms above normal levels. In

water columns, heavy metals must first be absorbed by phytoplankton, bacteria, algae and small organisms and then travel through the food chain to bigger animals and finally enter the human body. The over concentration of such elements in fish, other marine life and plants will cause negative effect. The greatest negative effects of heavy metals on man are known to be stress and nerve related complications; heart artery and vein system difficulties; blocking of body contaminant eradicators (Colon, skin, kidney, etc.), immune system hormonal glands and digestive system. In the case of marine life there are incomplete. some and drastic effects such as reduction of growth, behavioral changes, genetic alterations and death of fish

Materials & Methods

The present study was carried out for a period of 12months (for 1 year from January2010-2011). Sampling stations were chosen according to table 1 due to differences in the eco-system analyzed, which presented differences in the sea, Gorgan Bay and beal of Gharesoo river. The sampling took place on a seasonal basis. In assignment of sampling stations two points of interest stood out:

1) possible places covered by the sea, Gorgan Bay and River.

2) Site wastewater pollutants from various sources.

Table 1: Location of the sampling stations

Row

Station name

Latitude

Longitude

1

Sea ( Opp. Gorgan river)

36o 52' 42"

59o 50' 39"

2

Sea (Tower)

36o 52' 48"

59o 51' 12"

3

Interaction of sea with bay

36o 52' 57"

59o 52' 34"

4

Bay (Khoozin Canal)

36o 53' 06"

59o 55' 30"

5

Bay (Jahanshahi)

36o 53' 18"

59o 56' 02"

6

Gharehsoo River Delta

36o 53' 01"

59o 54' 00"

7

Gharehsoo River

36o 52' 46"

59o 51' 53"

8

Gharehsoo River

36o 50' 31"

59o 46' 32"

Samples were taken using anEkman Grabber with surface of 225cm2. Aftereachimpact of thegrabber with the desired areathecontentswere taken and placed in plastic containers, labeled with specifications and kept in a refrigerator until measuring. It should be noted that 3 samples were taken of sediment at each station and samples were prepared from the resultant 1 kilogram of the samples. Sampling and testing was according to the standard book methodology. In line with this research to establish the level of metals using the digestion method, a mixture of nitric acid and chloric acid was used. In guidelines no. 1 a summary of the stages of analysis and preparation of samples is shown according to this method. To eliminate interference, a 10% potassium solution was used. Reflux and heating reactions substantially increased the percentage of metal absorption. Washing of sediments was by 12.5% solution which will have the same effect on fish (Trefry, 1976). Also, for preparation of the standard solution pure metal or high concentration salts were used. To reduce the probable absorption of ions of metal in digested solutions in the inner layers of the containers until time of measurement of the metals contained therein, PE bottles were used (Betti-1988,. Sansoni, 1978). To measure heavy metals in digested samples a Swipe Absorption Spectrometer possessing nuclear exposed flame (FAAS) model (ShimadzuAA-670/GU-8) with a deuterium lamp was used. The accumulation of metals was measured using the Standard Curve method (according to concentration and absorption Volumes).The study compares data on sediments after first obtaining the average levels + standard deviation (X +SD) in terms of distribution and then compares their quantity with each other in order to explain the results from a PRISM statistical software and one way analysis of variance (ANOVA) and the results were group compared using Tukey statistical method and the statistical results at P<0.05 were considered acceptable difference criteria.

Results

Heavy metals in sediment samples: Results of the analysis of sedimentary bed of the southeast coast of the Caspian Sea represent

accumulated values of 2 elements, zinc (1213+13) at Station 1 and Pb (1021+11) at station 4 compared with chromium (315+8) at station 4 and cadmium (302+8 ug/kg dry sediment) at station 4 (table 2). As specified in the table, the values are almost uniform in the fluctuation of highest levels of elements observed in the sampling stations (Figure 2), where the concentration values of all elements at station 3 at the meeting point of seawater and the Bay is considerable.

Table 3: Concentrations of Heavy Metals in Sediment Samples (ug/kg Dry Weight)

Station

Pb

 

Cd

 

Cr

 

Zn

 

 

Max

Min

Max

Min

Max

Min

Max

Min

1

687

528

126

106

282

127

1213

824

2

721

489

293

131

232

98

926

721

3

721

234

159

102

281

175

986

721

4

1021

324

302

98

315

141

1012

481

5

927

412

201

102

302

89

875

702

6

726

624

181

121

179

99

1015

609

7

915

521

181

69

241

197

902

517

8

598

408

100

63

104

63

598

402

Pb      Cd      Cr Zn

1400

 

 

 

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Figure2: Fluctuation of highest levels of elements in the stations

As observed from the results of table 2, the levels of each element under study is different in each station 1334 ug/kg dry weight sediment penetrate the compared to the Witness Caspian Sea control station (113, 262 833.5, 1431 mg/kg dry weight sediment) and GharaSoo River. (950, 742.5, 102 and 98.5 ug/kg dry weight sediment) are the uniformity differences in that Lead and Zinc concentrations in the three regions compared to the two elements Chromium and Cadmium are higher. Comparing the results of the research by Jackson in 1990 which has calculated the maximum levels of lead and copper in the sediment bed of Bay Women in Alaska (levels have been stated.) shows that the element Lead has been observed in the area of research. Average levels of heavy elements in sediments in the research area is lower than the results obtained by Bortleson for the sediments of Lake Roosevelt. In his research the levels of copper and Lead in the sediments of this lake were respectively obtained as 85 and 310 and 970 mg/ kg where such a level rate was at a critical level for organisms identified in the region (Bortleson, 1992). It was also noted that the high level of heavy elements in the area in marine life which was the result of presence of elements in the sediment bed of the environment is indicative of the occurrence of a contamination crisis in the flora and fauna.Comparison of results obtained in the research area, the above research and standards presented indicate that the levels of these elements in the bed sediments of the research area are not at dangerous levels for the marine life (Akhondian, 1380). Levels of Lead, Zinc, Cadmium, Chromium in the sediment of Station 7, the entry point of urban wastewater and agricultural sewage are respectively in 1115, 985, 155, 306 mg/kg which trend in the case of the elements Lead and Cadmium have been reduced slightly at the next station, But the levels of Lead and Chromium in sediments from West to East show a growth trend. Therefore, considering the results obtained maximum contamination is observed near the coast and stations located at entry points of Gharasoo and Gaz rivers. Once more "due to entry of urban sewage From Kordkoy city estate and agricultural waste in the area

the level of Lead, Zinc, Cadmium, Chromium in the sediment bed of station 8 has increased and previous to that in the area of stations 6 and 7 which is the entry point of contaminants Gharehsoo and Gaz rivers, the level of absorption and accumulation of heavy elements has reached maximum levels in the sediments beds in the area. Therefore, in consideration of the results obtained maximum contamination occurs near the coast and at entry points of the Gharehsoo and Gaz rivers. Comparison of the average levels of heavy elements in the sediment beds of the southern coast of Caspian Sea with standards presented indicates the average level of Lead and Chromium in the sediments of the area is below that of standard sediment deposits in the ocean. But the level of Zinc is almost twice that of Lead and Cadmium is at the average standard of oceanic sediment deposits. The average level of all heavy elements in the sediments of the area is above the standards presented for surface sediments the reason for which may be said to be the effect of nature as well as natural contamination or land construction in the area plus coastal sediment accumulation. (table:3).In consideration of the high level of heavy elements in the sediments and entry varied contaminants to the area through urban, rural, industrial and agricultural sewage in the water board of the area and rivers leading to it, especially Gharasoo river and its natural effect on the marine life of the area, it seems vital to assess and determine the levels of heavy elements among the fish residing in the area.In reviewing the results of analysis of sediments and fish at Tigris River in Turkey there was indication that the accumulation of Lead in fish and sediments was a high level. The level of lead in sediments of Lake Roosevelt was announced at 310 mg./kg. (Bortleson, 1992). Studies of contaminants in Women Bay in National Wildlife Refuge off the shores of Alaska indicated that the level of heavy elements in the muscles of King Prawns is less than those in marine sediments and plants but above those in other fish muscles and other sediments (Jackson, 1990). To control heavy metal occurrence at the surface of water, in sediment and fish of the Caspian Sea the quality control of water of fish farms must be researched and the result of the analysis from fish farms and industry on the environment must be taken into account. Therefore, this

level of heavy metals in the soil and sea entering through rain and rivers from farming and industrial areas must be analyzed. Also, farmers and people must be given training in the case of formulation of pesticides and fertilizers as well as residential waste control entering rivers and the sedimentation process in the sea. Another vital requirement is creation of reference laboratories for periodic analysis of contaminants.

Table3: Comparison of Concentration of metals existing in sediments of Gorgan Bay with Concentrations of Same Metals in Sediments in the Rest of the World (micrograms/gram of Dry Weight)_

Area

Hg

Pb

Al

Cd

Sources

Distribution in Crust

0/08

12.5

81300

0.2

Dabiri, 2000

Beal Sediments in Savana, USA

Na-1.9

0.41-0.95

17-560

Na-1.2

Kumar et al,.2008

Caspian Sea, IRI

0.02-0.09

11.30-24.6

-

0.1-0.2

Demora and sheikh oleslami 2002

Caspian Sea, Azerbaijan

0.05-0.45

12.2-28.6

-

0.1-0.2

..........

North West of Persian Gulf

0.19

23.5

-

2.1

SabzAlizadeh 2008

Bandar Imam Sediments

1.4

6.97

30500

0.5>

SajadAbdollahiMamoran, 2009

Ezmir Bay

0.05

8.5

-

0.03

Aksu et al., 2008

References

Abdul-wahab,s.a.and jupp,B.P.,2009.Levels of heavy metals in subtidal sediment in the vicinity of thermal power/desalination plants,.acasestudy,Desalination 244,261-282.

Akhondian, M, 2001, The rate of accumulation of heavy metals in water, sediment,Kladofora algae, shrimp, on the southern coast of the Caspian Sea province - Golestan

Aksu,A.E.,Ysar,D.,and Uslu,O.,1997.Assessment of Marine Pollution in Izmir Bay:Heavy Metal and Organic Componund Concentration in surfical sediments. Turkish Journal of Engineering and Environmental Science 22,387-415.

AminiRanjbar, Gh, 1994, the rate of accumulation of heavy metals (zinc, copper, nickel, lead, cadmium) in the Anzali wetland sediment surface, the Iranian Fisheries Scientific Journal, No. 4, pages 13-22.

Betti , m.&.papoff,p.1988:Trace elements:Datainformations in the characterization of aqueous ecosystem.CRC critical reviews in analytical chemistry,vol.19 Issue4.

Bortleson , G.C., Cox,S.e. and Munn,M.D.,1992, Sediment-Quality Assessment of Franklin D.Roosvelt lake and the Upstream Reach of the columbia River. Washington.U.S Geological Survey open-file.Report,130p,94-315pp.

Brown,A.and Cmclachan.,1995.Ecology of sandy shores, Elsevier scince publishers B V.,New York.

Dabiri, M,1385. A farce environment (water - soil - air - sound). Alliance Publishing,

fourth edition. P. 399.

Demora, S.,and Sheikleslami,M.R,2002.Contaminant screening Program. Finalreport. Interpretation Of Caspian Sea Sediment Data.27p

Jackson,R.,1990,Alaska Maritime National Wildlife Refuge Womens Bay Contaminant Study ,U.S.Fish and Wildlife Service.

Kasuba,V.,Rozgaj,R.,2000.Biological effects of cadmium.period.biol.102,365-371.

Lam,p.k.s,yu,k.n.,ng.k.p.and chong,w.k.,1997.Cadmium uptake and depuration in the Soft tissues of brotiahainanensis (Gastropoda:prosobranchia:thiaridae) :a dynamic model. chemosphere 35,2449-2461.

Luoma,s.n.,1983,bioavailibity of trace metal to aquatic organisms,areview.the science of the total environment 28,1-22.

Sansoni , B.&.lyenger,V.1978:Sampling and sample preparation methods for the analysis of trace elements in biological material. KernforschungsaniagejulichGmbh.

Savvides,c.,Papadopoulos,A., haralambous,k.j.and Loizidou,m.,1995, Sea sediments contaminated with heavy metals ,.metal speciation and removal water science and technology 32,65-73.

Sbzlyzadh, S. 2008. Evaluation of heavy metals (cadmium - zinc - cobalt - nickel -Mercury - copper - lead) and the contamination in the sediments Lyfh - Saif. Khorramshahr University of Marine Science and Technology MS thesis, 119 pp.

Suzuki,n.,koizumi,n.,sano,H.,2001.screening of cadmium-responsive genes in arabidopsisthailand.plant,cell& Environment 24,1177-1188

Trefry,j.h.1997:Trace metal determination in soil and sediment .j .Env.Geol.Vol.1,283.

Heavy metals (Zn, Pb, Cd and Cr) in fish, water and sediments of Southern Caspian Sea, Iran

Mahmood Saghali1*, Rauf Baqraf2, Seyed Abbas Hosseini3, Parisa Nejatkhah Manavi4 and Bahador Moghimi Tilemi5

1 PhD student at Department of zoology University of National Academy of Sciences.Baku, Azerbaijan

2 Assistant of Department Ecology of Azerbaijan Oil Company.Baku, Azerbaijan

3 Member of Scientific Committee of Gorgan Agricultural Sciences University. Iran

4 Associated professor of Marine Biology Department, Islamic Azad University, North Tehran Branch. Iran

5 MS student of Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran,

* Corresponding author: Mahmood saghali

Postal address: IRAN-GOLESTAN PROVINCE-.FISHRY OFFICE

Phon.: 00989113755624, Fax: 00981712339314, E mail: M_saghali18@yahoo.com Abstract

Environmental pollution is a worldwide problem, heavy metals is one of the most important pollutants. Southern Caspian Sea coasts one of the most important aqua systems at the eastern south of Caspian Sea, which receives effluents discharges from heavily industrialized and highly populated settlements. Metals tend to accumulate in water and move up through the food chain. So, studies to ascertain the level of heavy metals in environment and determine potentially hazardous levels for human are necessary. In this investigation, concentration of four heavy metals (zinc [Zn], chromium (Cr), cadmium [Cd] and lead [Pb]) in four species of most-consumed fishes, water and sediments have been determined. Samples were collected from 8 stations along the Southern coast of Caspian Sea, in 2010-2011. Heavy metal concentrations were measured by graphite furnace atomic absorption spectrometry. Then, the data were analyzed by means of one-way analysis of variance (ANOVA) statistical analysis. The results showed that the

highest concentration of heavy metals in water and sediment and fish samples was related to Pb and Zn. The minimal and maximal concentrations of these metals in fishes, water and sediments were 98±4 - 39±4 and 75±3 - 126±7for Pb and Zn, respectively. However, the observed heavy metals concentrations in fish, water and sediments were below the recommended limits. The investigation showed elevating levels of heavy metals in environment. Thus, a serious notification to industrial and man-made pollution, which can lead to ecosystem and food chain contamination, is necessary.

Keywords: Concentration, heavy metals, pollution, fish, Gorgan bay, Caspian Sea

Introduction

Environmental pollution and its hazards are the most important problems of societies and living creatures. On the other hand, increased population with the development of technology and production can cause a lack of attention to environmental safety (Tabariet al. 2010). Industrialization leads to the pollution of ecosystems. Therefore, recognition of pollutants and prevention of their environmental dispersion are one of the necessities in this field. Therefore, we must determine the pollution sources, their environmental effects and prevention methods; also, filtration of industrial waste water and education of instructions for environmental protection is vital works to control and protect against pollutants.

Pollution is discharged into rivers and lakes and leaches into the soil and ground water or is emitted into air as particulate matter (Abernathy et al. 1984; Diagomanolin et al., 2004) also; this has increased the concerns about the accumulation of metals in sediments, biota and ultimately humans (Gibbs and Miskiewicz, 1995). Fish, as human food, are considered as a good source of protein, polyunsaturated fatty acids

 (particularly omega-3 fatty acids), calcium, zinc (Zn), and iron (Chan et al., 1999). In future, seafood will be an even more important source of food protein than they are today and the safety for human consumption of products from aquaculture is of public health interest (WHO, 1999). Fish from estuaries and coastal waters associated with industrial and sewage discharges have been found to be contaminated with heavy metals (Chan et al. 1999; Gibbs and Miskiewicz, 1995; Tariq et al. 1993). Metal residues problems in the fish flesh are serious, as reflect by the high metal concentrations recorded in the water and sediments (Wong et al. 2001). On the other hand, heavy metals are critical in this regard because of their easy uptake into the food chain and because of bioaccumulation processes (Beijer and Jernelo"v, 1986; Diagomanolin et al.2004). Metals tend to accumulate in water (Daka et al. 2003; Fo"rstnerand Wittmann1979) but may be released under certain physicochemical conditions, moving up through the food chain (Bryan and Langston, 1992). It is of vital importance, hence studies are conducted to ascertain the level of concentrations of these metals in environment (Biney, 1991; Okoye, 1991) and determine potentially hazardous levels for human. Several studies were done to measure and determine the effects of heavy metals and trace elements on ecosystem and human. The studies showed that decreased content of antioxidative elements, such as Zn, selenium (Se) and manganese (Mn) and increased content of some elements including cupper (Cu), cobalt (Co) and arsenic (As), which probably elevate the oxidative stress, can cause some inflammatory diseases and cardiac functional disorders (Barandier et al. 1999; De-Lorgeril et al.2001; Topuzoglu et al. 2003). Cadmium (Cd) was reported to be associated with prostatic cancer, osteomalacia, inhalation toxicity and nephrotoxicity. In addition, chromium (Cr) was shown to be associated with some disorders, such as nasal septa defect.

Gorgan bay is located from 36_50' to 37_ North and 53_30' to 53_50' East in the northern part of Iran and southeastern of Caspian Sea in the Golestanprovince. The coast is one of the most important ecosystems in the north of Iran, and receives different inputs from an industrial layout in addition to wastes from a high-density settlement (NejatkhahManavi et

al. 2010).

Presence of heavy metals in Caspian Sea poses a risk for food contamination and heavy metals and trace elements can cause hazards on ecosystem and human health.

Therefore, the aim of the study is the comparison and analysis of heavy metals (Cr, Cd, Zn and Pb) in water, sediment and four species of most consumed fishes (Cyprinuscarpio, Mugilaauratus, Rutilusrutilus and Rutilusfrisikutum) in eastern coast of the Caspian Sea and Gorgan Bay.

Materials and Methods

8 Sampling stations were chosen due to differences in the ecosystem analyzed, which presented differences in the sea, Gorgan Bay and Beal of GharesooRiver (Table 1, fig 1).

Fig 1.Sampling sites in Gorgan Bay and Caspian Sea

Seasonal sampling took place for one year in 2010- 2011. In assignment of sampling stations two points of interest stood out:

1) possible places covered by the sea, Gorgan Bay and River.

2) Site wastewater pollutants from various sources. Sampling, Preparation and Chemical Analysis:

1 liter of water in each sitewas taken using Nance bottles.The watersamples was gently heated and evaporated to approximately 30 mlafter passing through Watman 42 filters. Next, 1 ml of samples were added to normal 14.44 or 65% Nitric Acid and again filtered and stored

in PE containers.Sediments were taken by the Van Veen Grab and heated in the electric oven at 70oC. The dried samples were separated using sieve no. 230. Samples softened and homogenized using a pestle and mortar and 1 gr was weighed using a digital scale (with 0.001 gr precision) and 5 ml of nitric acid with 5 ml chloric acid (1:1) were added and placed on a water bath at 100oC. The solution was passed through a Watman 42 filter and its volume was increased to 30 ml with distilled water.Most of the specimens under discussion in the area of research were purchased from fishermen in Gorgan Bay and Caspian Sea and took to the laboratory. A part of the chest muscle of the fish were isolated and after washing were placed in the Oven at 70 oC for 72 hours. 1 gr of dried samples were softened and homogenized with marble pestle to distribute chemical analysis, after which the heavy elements were measured. In line with this research to establish the level of metals using the digestion method, a mixture of nitric acid and Chloric acid was used. To eliminate interference, a 10% potassium solution was used. Reflux and heating reactions substantially increased the percentage of metal absorption. Washing of sediments was by 12.5% solution which will have the same effect on fish (TrefryandParsley1976). Also, for preparation of the standard solution pure metal or high concentration salts were used. To reduce the probable absorption of ions of metal in digested solutions in the inner layers of the containers until time of measurement of the metals contained therein, PE bottles were used (Sansoniand lyenger1978). To measure heavy metals in digested samples a Swipe Absorption Spectrometer possessing nuclear exposed flame (FAAS) model (Shimadzu AA-670/GU-8) with a deuterium lamp was used. The accumulation of metals was measured using the Standard Curve method (according to concentration and absorption Volumes). It should be noted that all standard consumed solutions were consistent with the Merck standard with concentration of 1000 ppm, depending on the type of metal analyzed (Krajca, 1989).

The study compares data in water, sediments and fish (muscle) after first obtaining the average levels ± standard deviation (X ±SD) in terms of distribution and then compares their quantity with each other in order

to explain the results from analysis of variance (ANOVA) and the results were group compared using Tukey statistical method and the statistical results (p < 0.05) are considered acceptable difference criteria.

Results

Heavy metals in fish:

The results of heavy metals in fish samples are presented in Table 2. As shown, the levels of the elements under study are different in each fish species. Among the four measured elements, concentrations of Zinc, Lead, Cadmium and Chrome were highest respectively. Highest concentrations of Lead were observed in Cyprinuscarpio, zinc and cadmium in Mugilauratus and Chrome in Rutilusfrisikutum while, the lowest concentration of zinc and cadmium and Lead were observed in Rutilusrutilus.The highest concentrations of Cd ranged from 75±1to 28±2ug / kgand were related to Cyprinuscarpio fishes in the fishing stations. Also, Cyprinuscarpio had the highest levels of these three heavy metals than Mugilauratus and Rutilusfrisikutum (P< 0.05). The lowest value of Pb was found in Rutilusrutilus (72±7ug / kg), while the highest value was found in Cyprinuscarpio (98±4ug / kg); the mean concentration of Pb in the fishes was significantly higher than that of Cd and Cr levels (P< 0.05).The order of the heavy metals concentration in Cyprinuscarpio was Pb> Cd > Cr.Also, the order of the heavy metals concentration in Mugilaauratus and Rutilusfrisikutum and Rutilusrutiluswas>Pb> Cr > Cd.

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