Mercury concentration in some species of fresh water fish of bangladesh
Upcoming SlideShare
Loading in...5
×

Like this? Share it with your network

Share

Mercury concentration in some species of fresh water fish of bangladesh

  • 2,161 views
Uploaded on

 

More in: Business , Technology
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads

Views

Total Views
2,161
On Slideshare
2,160
From Embeds
1
Number of Embeds
1

Actions

Shares
Downloads
14
Comments
0
Likes
0

Embeds 1

http://www.slideshare.net 1

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Journal of National Oceanographic, Atmospheric and Marine Institute ©NOAMI Vol.24, No.2, 2007 ISSN: 1027-2119 MERCURY CONCENTRATION IN SOME SPECIES OF FRESH WATER FISH OF BANGLADESH A.K.M.Sharif Bangladesh Atomic Energy Commission, Dhaka-1000, Bangladesh M.Alamgir, Stanly A.Bajue and Rashed Alam Department of Physical, Environmental and Computer Sciences Medgar Evers College, CUNY, NY, U.S.A. _____________________________________________________________________________________ Abstract: Mercury concentration in edible portion of some popular sweet fish species namely,Tenualosa Ilisha,Pangasius pangasius, Septinna phasa, Neopropius atherinoides,Otolithoides pama , Puntius sarana,Ompok pabda, Sperata aor, Clarias batrachus, Heteropneustes fossil ,Labeo rohita, and Catla catla were determined by radiochemical neutron activation analysis (RNAA). The results were found to vary from 0.243 to 0.675 µg g-1 on dry weight, where four species had mercury concentration, 0.243 - 0.299 µg g-1, six, 0.303-0.384 µg g-1 and the rest two, 0.536-0.675 µg g-1. The results were found to agree well with other published data on river and marine fishes and within permissible level accepted internationally. Key words: Mercury, Fish, Radiochemical neutron activation analysis, Bangladesh. _____________________________________________________________________________________ INTRODUCATION Mercury is one of the most toxic elements to man and other animals. In the last two decades, measurement and evaluation of mercury in environment has received much attention. The presence of high concentration of mercury in river and marine organisms is well–documented (Lee and Hultberg, 1990: Bjorklund et al., 1981: Akielazek and Haines, 1981 and Bacci, 1989). Investigatiions of heavy metals in aquatic ecosystems have been well documented in Europe, Australia and North America, but few studies are available about the level of contamination, particularly that of Hg in the fishes from rivers, and of the Bay of Bengal. Sharif et al., (1991, 1993a, 1993b) reported level of few metals including Hg in some river and marine fishes of the Bay of Bengal. In the rivers and sea, mercury comes mainly from weathering, sewage disposal and industrial wastes. From discharges of Chloro-alkali industries of Chittagong and Sylhet, through the rivers,theKarnaphuli
  • 2. J.Nat.O.A.M.Institute Vol.24, No.2, 2007 and the Surma, mercury comes to the Bay of Bengal. Nearly, one hundred and eighty tons of Hg is introduced every year into the Indian environment alone (Chaudhury, 1980). Yearly 2.4 billion tons of sediments (Holeman, 1968; Coleman, 1969 and Khan, 1978) are carried by the river system of Bangladesh. Thus the high mercury level in the Bay of Bengal may be due to direct disposal of industrial wastes or solid wastes dumped by rivers of the subcontinent. An estimated value of Hg content in daily diet varies from 5 to 20 mg and may reach up to 100- 300 mg in coastal areas (Sharif et al., 1993b). Fish can accumulate both organic and inorganic mercury in its metabolic system and they are the natural sources of Hg to man (Chovjka and Williams, 1980). The total intake of Hg from other sources is negligible ( Clarkson, 1984; Turner et al., 1980). People living to the coastal areas are directly or indirectly dependent on the resources of the sea. The main objective of the present study is to know the level of mercury in the tropical fresh water fishes of rivers of Bangladesh ,and to compare whether it is safer or not health. MATERIALS AND METHODS Samples of Collection Fish samples of Tenualosa Ilisha,Pangasius pangasius, Septinna phasa, Neopropius atherinoides,Otolithoides pama , Puntius sarana,Ompok pabda, Sperata aor, Clarias batrachus, Heteropneustes fossil ,Labeo rohita, and Catla catla were collected from different fish markets of Dhaka, Commilla,Chandpur,Chittagong,Sylhet,and Khulna. Special precautions were taken during their collection and preservation in containers so that these specimens were kept in good condition. Their weights and sizes were recorded. The samples were cleaned and washed with demineralized water. Only the flesh samples after removal internal organs, head, skin and tails, were taken out from the body. These samples were sun-dried .The dried samples were then chopped into pieces with the help of a stainless steel knife (steam cleaned). Only the edible muscle tissue samples were used for analysis. The samples pieces were dried at 105-110oC in an oven until a constant weight was obtained (dry weight) .The dried samples were ground, sieved and thoroughly mixed in a stainless steel rotating drum for 100 hours to produce a homogeneous powder .These powder samples were finally preserved in clean and dry analysis polythene bottles prior to analysis. All the chemicals and reagents were of analytical grade. 2
  • 3. J.Nat.O.A.M.Institute Vol.24, No.2, 2007 Irradiation Portions of the samples (200-300 mg each) were thermally sealed in polyethylene bags and irradiated for 15 hours along with a known amount of MA-A-2™, the fish flesh homogenate standard of IAEA (International Atomic Energy Agency) in the TRIGA MARK II reactor at AERE, Savar, Dhaka at a flux of about (0.5 to 1.0) x1012 n.cm-2.s-1. Radiochemical Separation The process for dissolution and chemical separation was the same as our process described elsewhere (Sharif et al .1993b). Counting The samples and the standard were counted on a 125cm3 HPGe detector connected to a 4096 pulse height analyzer PCA II MCA card. The energies (in keV) chosen for the evaluation of the peak areas were [197Hg: t1/2 (65 h)] Eγ = 69 and 77.3 keV. The minimum detection limit was one nanogram for mercury for the total sample volume. The counting errors at the detection limits were around 7% .The blank polyethylene bag did not show any measureable mercury content. Accuracy and Precision Experiments were initially carried out using a radioactive tracer and the corresponding carrier to evaluate the recovery. The accuracy of the method was evaluated by analyzing the homogenate fish flesh (IAEA) Standard Reference Material, MA-A-2 (TM). The mercury concentration was 0.45± 0.06-µg g-1 and this is in good agreement with the IAEA certified value (0.47±0.02 µg g-1). RESULTS AND DISCUSSION The concentration of mercury found in the samples of fish has been shown in Table 1. Mercury concentration was observed at the level 0.243 to 0.675 µg g-1 in these samples. The highest concentration (0.582-0.836±0.127 µ g g-1) is found in Setipinna phasa and the lowest (0.250-0.260±0.004 µg g-1) Neopropius atherinoides. It is observed that the level of Hg in fishes of fresh water origin is much lower than that in other countries. A. comparison of mercury concentrations in some fresh water fish available in Bangladesh and West Bengal (India) (µg g-1 dry weight basis) is shown in Table 2. A relationship between the amount of mercury (µg g-1) and the number of fishes is shown in Figure 1. 3
  • 4. J.Nat.O.A.M.Institute Vol.24, No.2, 2007 Table.1. Mercury concentration in different varieties of fresh water Fish of Bangladesh (µg g-1 dry weight basis) Type of fish(Local Scientific names Mercury Mean Names In Bangladesh 1. Hilsa Shad (Ilish) Tenualosa ilisha 0.334-0.442±0.052 0.364 2. Yellow tail catfish (Pangas) Pangasius pangasius 0.355-0.426±0.027 0.384 3. Gangetic hairfish Anchovy(Phasa) Setipinna phasa 0.582-0.836±0.127 0.675 4. Indian potasi Neopropius (Batashi) atherinoides 0.250-0.260±0.004 0.253 5. Pana croaker (Poa) Otolithoides pama 0.277-0.342±0.027 0.303 6. Olive barb (Shorputi) Puntius sarana 0.22-0.44±0.11 0.35 7. Pabo catfish (Pabda) Ompok pabda 0.230-0.264±0.015 0.243 8. Long-whiskered Catfish (Ayre) Sperata aor 0.267-0.875±0.304 0.536 9. Walking catfish (Koi) Clarias batrachus 0.246-0.344±0.042 0.295 10. Air breathing fish (Singh) Heteropneustes fossil 0.288-0.320±0.016 0.299 11. Ruhu (Rui) Labeo rohita 0.214-0.448±0.167 0.323 12. Catla (Katol) Catla catla 0.250-0.340±0.045 0.303 Average:0.362 µg g-1 Range: 0.243-0.675 µg g-1 4
  • 5. J.Nat.O.A.M.Institute Vol.24, No.2, 2007 Table 2.Comparison of Mercury concentrations in some in Frash water fish available in Bangladesh and West Bengal (India) (µg g-1 dry weight basis) Type of fish(Local Scientific names Mercury Mercury Names (Bangladesh) (West Bengal, In Bangladesh and India) India** 1. Hilsa Shad (Ilish) Tenualosa ilisha 0.334-0.442±0.052 0.55-0.83 2. Yellow tail catfish (Pangas) Pangasius pangasius 0.355-0.426±0.027 0.22-0.52 3. Gangetic hairfish Anchovy(Phasa) Setipinna phasa 0.582-0.836±0.127 0.96-1.09 4. Indian potasi Neopropius (Batashi) atherinoides 0.250-0.260±0.004 0.25-0.42 5. Pana croaker (Poa) Otolithoides pam 0.277-0.342±0.027 0.20-0.35 6. Olive barb (Shorputi) Puntius sarana 0.22-0.44±0.11 0.48-0.60 7. Pabo catfish (Pabda) Ompok pabda 0.230-0.264±0.015 0.20 8. Long-whiskered Catfish (Ayre) Sperata aor 0.267-0.875±0.304 0.20-1.02 9. Walking catfish (Koi) Clarias batrachus 0.246-0.344±0.042 0.28-0.40 10. Air breathing fish (Singh) Heteropneustes fossil 0.288-0.320±0.016 0.20-0.47 11. Ruhu (Rui) Labeo rohita 0.214-0.448±0.167 0.20-0.59 12. Catla (Katol) Catla catla 0.250-0.340±0.045 0.20-0.59 5
  • 6. J.Nat.O.A.M.Institute Vol.24, No.2, 2007 ________________________________________________________________________________ **Mercury in Fish : A Global Health Hazard, Mercury Policy Project, pp 1-51 ZeroMercury, February 2009 (Edward Groth III, PhD, Groth Consulting Services, Pelham, NY, USA) _________________________________________________________________________________ Figure 1 0.8 0.7 0.6 Amt. Of Hg (µgg^-1) 0.5 0.4 0.3 0.2 0.1 0 1 2 3 4 5 6 7 8 9 10 11 12 No. of fish Though the liver and kidney are usual organs for major concentrations of metals but mercury is accumulated at higher level only in the muscle of fish (Peterson et al., 1973) and in its case biomagnifications occurs through food chain. The permissible limit varies a little bit from country to country. One proposed by FDA (Food and Drug Administration) of the United States is 500 ppb. The mercury level in the present investigation is much lower than this value. The trend of increasing concentration of Hg with increases in size of fish indicates long time of its conservation in fish. Estimation of Dietary Intake of Hg in Bangladesh Average concentration of Hg found in the samples fish of the Bay of Bengal is 0.343±0.525 µg g-1. Assuming Maximum average of fish consumption person-1 day -1 is 6-10 g dry fish for Chittagong and 6
  • 7. J.Nat.O.A.M.Institute Vol.24, No.2, 2007 coastal areas of Bangladesh, the maximum Hg intake through fish is estimated to be 2.06-3.43 µg person-1 day-1 . This value is well below the maximum acceptable level for human being (0.5 µg g-1 wet weight) (WHO, 1976: FAO/WHO, 1972-1987: Nauen, 1983: Denton et al. ,1996: Hakanson et al.,1988. Similarly, 70 g dry per week would result in an intake of 24.01 µg of Hg which is also below the tolerable limit (0.7 mg( kg)-1 body wt.day-1 ) of an about 70 kg man as suggested by WHO (1976). CONCLUSION The level of mercury reported here may be taken as a convenient baseline for determining future pollution trends. Low Hg content observed in this study indicates that the Bay of Bengal has pollution free and clean environment. So there is no danger to have these fishes for a Bangladeshi person. Acknowledgement The authors express thanks to Mr.K.R.Krishnamorti, Analytical Chemistry Division, Bhava Atomic Research Center, Trombay, India, for using the method, the radiochemical separation of trace metals in biological samples, used in that Laboratory. REFERENCES Akielazek.J.J. and Haines,T.A.(1981). Mercury in the muscle tissue of fish from three northern marine lakes, Bull Environ. Contom.Toxically, 27, pp. 201-208 Bacci,E.(1989) Mercury in the Mediterranean, Mar.Pollute.Bull. , 20(20,pp.59-63 Bjorklund, I., Borg, H. and Johanssson, K. (1981), Mercury in Swedish lakes, its regional distribution and causes, Ambio., 3, pp 118-121. Chaudhury, N. (1980) , Ind..Exp., 48, p 9. Chovjka,R. and Williams, R.J. (1980) Aust.J.Mar.Fresh water Res., 31, pp. 469-473. Clarkson, T.W .(1984), Mercury, In: J.O.Nriagu (ed.) Changing Metals Cycles and Human Health, Springer Vertag, Berlin, pp. 258-309. Coleman, J.M. (1969) , Bhrahmaputra Rivers: Channel Processes and sedimentation, Sedimentary Geology, Vol. 3(2-3), pp. 129-238. Denton, G.R.W. and Burdon-Jones, C (1996), Trace metals in fish from Great Barrier Reef. Marine. Pollute. Bull. 30(5), pp. 201-209. 7
  • 8. J.Nat.O.A.M.Institute Vol.24, No.2, 2007 FAO/WHO (1972-1987), Joint FAO/WHO Expert Committee on Food Additives, Reports 505, 631, 696 and 751. World Health Organization, Geneva. Hakanson, L., Nilsson, A. and Andersson, T.(1988), Mercury in fish in Swedish Laeks, Environ Pollut., 49, pp. 145-162. Holeman, J.N. (1968), The sediment field of major rivers of the world, Water Resources research, Vol.4 (4) pp. 737-747. Khan.H.R. (1978) A Study of Water Resources Development Activities in Bangladesh. A report for Ford Foundation, Dhaka, p. 87. Lee,Y.H. and Hultberg, H.(1990), Methylmercury in some Swedish surface waters, Environmental Toxicology and Chemistry, Vol. 9, pp.833-841. Nauen, C.E.(1983) , Complication of legal limits for hazardous substances in fish and fishery products, FAO Fish Cric., 764. Peterson, C.L., Klawe,W.K. and Sharp G.D.(1973), Fish Bull., 71. pp. 603-612. Sharif, A.K.M., Mustafa, A.I., Amin.N.M. and Safiullah,S (1991). Sci .Total Environ., 107, pp. 135-142. Sharif, A.K.M.,Mustafa,A.I., Mirza, A.H. and Safiullah,S.(1993a), Sci. Total Environ., 138, pp. 223-234. Sharif. A.K.M., Alamgir, M., Krishnamoorty, K.R. and Mustafa, A.I. (1993b), Nucl.Chem., 170, pp.299- 307. Turner, M.D., March, D.O., Smith, J.C., Inglics, J.B., J.B., Clarkson, T.W., Rubio, C.E., Chirboga, J. and Chiriboga, C.C.(1980), Methylmercury in population eating large quantities of marine fish, Arch.Evviron. Health., 35, pp. 367-370. WHO (1976) , Environmental Health Criteria, I-Mercury, WHO, Geneva. 8