DETERMINATION OF MERCURY IN FISH FROM DOPOULAN RIVER

MEHDI RAISSY

Department of Aquatic Health, Faculty of Veterinary Medicine, Shahrekord Branch, Islamic Azad University, Shahrekord, E-mail; [email protected]

Abstract— Mercury pollution has been recognized as a potential environmental and public health problem for over forty years. The major source of exposure to mercury for humans is the ingestion of fish. The present study was conducted with the aim of determining the levels of mercury in the muscles of five fish species caught in Dopoulan River and comparing the results with the maximum tolerance levels. Forty fish samples were used for determination of mercury by graphite furnace atomic absorption spectrometry. The results revealed that the concentrations ranged from 0.53 µg/g to 1.02 µg/g, with means of 0.86 µg/kg. Concentration of mercury was lower than the threshold limits acceptable by WHO standards in all studied samples with no harm for human.

Index Terms—Fish, Mercury, Atomic absorption spectrometry.

I. INTRODUCTION carcinogenesis [6]. The importance of determining mercury concentrations is further emphasized Heavy metals are considered the most important form considering the WHO recommendation that the daily of pollution of the aquatic environments because of oral intake of mercury should not exceed 500 µg kg-¹ their toxicity and accumulation by marine organisms in sea food [7]. including fish and shell fish. Heavy metals can be Dopoulan River is located in Chaharmahal va classified as potentially toxic (aluminium, arsenic, Bakhtiari Province and is an important river leading to cadmium, lead, mercury), probably essential (nickel, Karoon river which is one of the most rivers in Iran [8]. vanadium, cobalt) and essential (copper, zinc, From the ecological point of view, Dopoulan River selenium). Mercury and arsenic which are potentially have a special importance as it is habitat of different toxic metals can be very harmful, even at low native and non-native fish species. It is also important concentration, when ingested over a long time period fishing and fish culture area. In recent years [1]. Toxic metals such as mercury and arsenic can enter agricultural activities have been developed around it aquatic environment and body of aquatic such which are accompanied with releasing agricultural as fish, shellfish, shrimp, oyster and other types of swages and pesticides containing toxic metals into seafood by absorption through the gills or by water. absorption through food, but it appears that the second Hence, it is important to investigate the levels of heavy is the more important. Shrimp, in particular, is a metals in fish from this place to assess whether the species that has numerous pathways for concentration is within the permissible level and will bioaccumulation of metals and other pollutants not pose any hazard to the consumers. including absorption at the gill surface, ingestion of The objective of this study was to determine the level water and sediment and consumption of organisms of mercury in fish muscles and harms possibly arising which themselves have accumulated pollutants [1]. from the use of the water and consumption of its The most common sources are industrial and mining aquatic life activities, petroleum exploration, effluent processing and management, atmospheric condensation, and II. MATERIALS AND METHODS disposal of agricultural sewage. Natural phenomena such as earthquakes, landslides, tornadoes and A. Fish samples cyclones have also been implicated [2]. Heavy metals Submit your manuscript electronically for review. are persistent and not biodegradable [3]. Food, A total of 40 fish of five different species were especially fish, is a major source of mercury exposure collected from Dopoulan River including Carassius which makes the monitoring of mercury in food an auratus gibelio, Alburnus alburnus, Chondrostoma important area of study [4]. Biotransformation of regium and damascina and Capoeta aculeata mercury and methyl mercury formation constitutes a which are the most commonly consumed fishes. problem for human health [5]. Exposure to mercury Identification of the fishes was carried out according to can cause various health effects such as irritation of the Abdoli [9]. Fish samples were transported in boxes stomach and intestine, decreased production of blood filled with ice to the laboratory. Weights and lengths cells, skin changes and lung irritation. High exposure were measured before the edible muscles were to mercury can cause infertility and miscarriages with dissected from the fishes. Samples were stored at -18ºC women, and finally it can damage DNA leading to before analysis.

Proceedings of The IRES 15th International Conference, Spain, Barcelona, 14th November 2015, ISBN: 978-93-85832-37-6 18 Determination of Mercury in Fish From Dopoulan River B. Apparatus prepared by dissolving 10 g in 100 ml of 6 M HCl. The A Perkin Elmer Model 4100 atomic absorption solution was boiled for about 5 min, cooled, and spectrometer equipped with a GTA Graphite furnace nitrogen bubbled through it to expel any mercury and deuterium background corrector was used. impurities Samples were injected into the graphite furnace using Perkin Elmer AS-800 autosampler. The atomic D. Determination of mercury absorption signal was measured as a peak height mode Fish samples were dried at 70ºC for 24 hours and then against an analytical curve. Perkin Elmer Analyst 4100 were homogenized. The homogenized samples were model AAS equipped with CVAAS system was used digested using the wet digestion techniques [4]. An for mercury determination. The recoveries of the atomic absorption spectrometer (Perkin-Elmer model metals were determined by adding increasing amounts 4100) equipped with deuterium background corrector of mercury to the samples and taking them through the and, mercury/hydride generator (Perkin-Elmer model digestion procedure. MH10) with an open quartz tube was used. The signals were recorded on a printer sequencer (Perkin-Elmer) C. Reagents Recoveries of the metals were determined by adding All the plastic and glassware were soaked in nitric acid increasing amounts of mercury to the samples and for 15 min and rinsed with deionized water before use. taking them through the digestion procedure. The All reagents and solvents were of analytical reagent mean recovery of mercury was 96.3 % (Table I). grade (Merck, Germany). Double distilled water was used for the preparation of solution. The stock E. Statistical analysis solutions of mercury and arsenic (1000 mg/L) were Data were transferred to Microsoft Excel spreadsheet obtained by dissolving appropriate metal salts (Merck, (Microsoft Corp., Redmond, Washington, USA) for Germany). The working solution were freshly prepared analysis. SPSS 18.0 statistical software (SPSS Inc., by diluting an appropriate aliquot of the stock solutions Chicago, Illinois, USA), was used for ANOVA and using 1 M HCl and 5% H2SO4 for diluting mercury Student’s t-test analysis; differences were considered solution and 7 M HCl for diluting arsenic solution. significant at values of p<0.05. Stannous chloride, for mercury analysis, was freshly

TABLE 1: RECOVERY OF MERCURY FROM FISH SAMPLES Concentration of metal added (µg g-1) Concentration of metal recovered (µg % Recovery g-1) 0.010 0.0099 99 0.020 0.019 95 0.040 0.038 95 Data are mean of three samples of three replicates. >4 yr. No statistical difference was observed between III. RESULTS these groups (p>0.05).

A total of forty fish samples including 4 native fish, TABLE 2. MERCURY CONCENTRATION IN STUDIED Capoeta damascina, Chondrostoma regium and SAMPLES (µG G-1) Alburnus alburnus and Capoeta aculeata and one non-native, Carassius auratus gibelio, were analyzed for mercury (Figures 1-3). The results indicate that the concentrations vary from 0.53 to 1.02 µg/g (mean=0.86 µg/g). The concentrations of mercury were statistically different in the different fish species (p<0.05); as the highest concentrations were found in Alburnus alburnus, and the lowest in Capoeta aculeata and Carassius auratus gibelio (Table II and Table III). Concentration of mercury was 0.53 µg/g in Capoeta damascina, 0.86 µg/g in Chondrostoma regium, 0.85 µg/g in Alburnus alburnus, 1.02 µg/g in Capoeta aculeata and 0.72 µg/g in Carassius auratus gibelio. According to the results, mean concentrations of mercury in the studied fish are lower than the maximum allowed levels according to WHO standards [7], [10]. To compare fishes with different age, they were divided into 3 groups including 2-3yr, 3-4yr, and

Proceedings of The IRES 15th International Conference, Spain, Barcelona, 14th November 2015, ISBN: 978-93-85832-37-6 19 Determination of Mercury in Fish From Dopoulan River TABLE 3. AGE, LENGTH, WEIGHT OF STUDIED FISHES Fish species Age (yr) Length (cm) Weight (g) Range Mean Range Mean Range Mean Capoeta aculeata 1-3 2 10.2-21 14.1 25.4-193 74.5

Carassius auratus 1-3 2.3 11.1-18.9 13.7 31.5-370 70.2 gibelio

Alburnus alburnus 1-3 2.2 8.1-13.9 11.1 19.1-68.5 54.9

Capoeta 1-3 2.2 12.2-19.7 15.3 33-176.4 91.2 damascina

IV. DISCUSSION water and sediment and consumption of organisms which themselves have accumulated toxic metals. Mercury is recognized as a global environmental Thus bioaccumulation of metals in fish can be utilized pollutant, with high toxicity even at low as effective indicators of environmental metals concentrations. Mercury strongly bioaccumulates in contamination. Bioaccumulation and toxic effects of aquatic food, and about 95% of the methyl mercury in heavy metals in cultured and wild aquatic species have human is originated from aquatic organisms [11]. been reviewed in many countries including Iran Mercury and methyl mercury are neurological Differences observed in the mean concentrations of toxicants to humans [12]. Methyl mercury is classified mercury in the studied fish species can be related to as a group C possible human carcinogen. Accordingly, different factors such as age, size, sex, season, and the tolerable weekly intake (1600 μg g-1 bw) environmental factors. It has also been reported that established by the Commission of the European cooking reduces the amounts of some metals [15]. Communities [13] has led to regulatory guidelines for Despite the ecological importance of Dopoulan River, the mercury concentrations allowed in seafood being only a few studies have been done on the accumulation established in several countries. The European of heavy metals in fish and shellfish in this area. At the Commission Decision 1881/2006 sets the maximum time of this study, little was known about the mercury limit for mercury in seafood at 500 μg kg-1 for fresh and arsenic level in tiger shrimp from the Persian Gulf food, increasing to 1000 μg kg-1 for the edible parts of while the mentioned metals have been widely studied some listed species that, for physiological reasons, in other places with similar ecological importance. concentrate mercury more easily in their tissues [13]. Regarding the absence of industrial activities along the The 500 μg kg-1 recommended guideline for mercury lagoon, the most important sources of heavy metals are concentrations in fish for human consumption is geogenic and agricultural sewage. To conserve the effectively a global guideline with North American endemic fish species and to prevent transmission of (USEPA & Health Canada) regulatory agencies heavy metals to humans prevention of drainage of enforcing the same limit [14]. The results presented in pesticides and fertilizers from surrounding crop fields this study show that the mean concentrations of is important. No other data are available from the same mercury in fishes are lower than maximum permitted area for comparison but it seems that mean levels according to international standards [7], [10] and concentration of mercury is lower than in fishes of are suitable for human consumption. some water basins close to the lagoon including Aquatic species including fish may take up heavy Beheshtabad River (26.8 µg/kg), Sooleghan Lagoon metals from water and sediments as demonstrated (22.3 µg/kg) and Gandoman Lagoon (30.7 µg/kg) previously in the oyster. Fish have numerous pathways (Table IV) [16]. for bioaccumulation of metals and other pollutants including absorption at the gill surface, ingestion of

TABLE IV. COMPARISON OF TRACE METAL CONCENTRATIONS IN SHRIMP IN THIS STUDY WITH OTHER RESEARCHES (ΜG G-1)

Location Metals levels References

Persian Gulf (Iran) Hg: 75-182 [17]

Persian Gulf (Kuwait) Hg: 500-2660 [18]

Proceedings of The IRES 15th International Conference, Spain, Barcelona, 14th November 2015, ISBN: 978-93-85832-37-6 20 Determination of Mercury in Fish From Dopoulan River Persian Gulf (Iran) Hg: < 500 [19]

Marmara Sea () Hg: 56-1136 [20]

Barents Sea (Norway) Hg: 170-340 [21]

Malaysia Hg: 210-570 [22]

Gheshlagh dam, Iran Hg: 67 [23]

Caspian Sea, Iran Hg: 97 [24]

Anzali lagoon, Iran Hg: 70 [25]

Caspian Sea, Iran Hg: 849 [26]

Lake Cochichewick, USA Hg: 900 [27]

Northeast North America, USA Hg: 290 [28]

Dopoulan River (Iran) Hg: 0.53-1.02 Current study

CONCLUSION [9] A. Abdoli. The inland water fishes of Iran, 1st edition, Tehran: Naghshe Mana Publications, pp. 25-245, 1999. [10] CIFA. Committee for Inland fisheries of Africa. Report of the The results presented in this study show that the mean third session of the working party on pollution and fisheries. concentrations of mercury in fishes are much lower FAO Fisheries report No. 471. Food and Agriculture than maximum permitted levels according to Organization of the United Nations, Rome, 1992. [11] J. Burger. and M. Gochfeld. Heavy metals in commercial fish international standards and are suitable for human in New Jersey. Environ. Res. Vol. 99, no. 3, 403-412, 2005. consumption. Fish from the aforementioned locations [12] Commission of the European Communities. Commission should be analyzed more often with respect to toxic Regulation (EC) No. 221/2002 of 6 February 2002 amending metals not only from the human consumption point of regulation (EC) NO. 466/2002 setting maximum levels for certain contaminants in foodstuffs. Official J Eur Comm, 2001. view but also from the environmental point of view. [13] Commission of the European Communities. Commission regulation (EC) no. 1881/2006 of 19 December 2006 setting REFERENCES maximum levels for certain contaminants in foodstuffs. Official J Eur Comm. L364–5/L364-24, 2006. [14] EPA. National Guidance: Guidance for Assessing Chemical [1] R. J. Wagman. “The Environment and Health,” In, The New Contaminant Data for Use In Fish Advisories, Volume 2: Risk Complete Medical and Health Encyclopedia, vol. 3. Chicago: Assessment and Fish Consumption Limits, Third Edition, Ferguson, pp. 956-964, 2000. Washington, D.C.,: U.S. EPA, pp. 45-80, 2000. [2] I. T. Nathaniel, A. T. Salami, and A. C. Olajuyigbe. [15] M. B. Atta, L. A. El-Sebaie, M. A. Noaman and H. E. Kassab. Environmental Features of Nigerian Economic Exclusive Zone The effect of cooking on the content of heavy metals in fish. (EEZ): Ibino and Bonny as case study. Afr. J. Environ. stu. Food chem. Vol. 58, no. 4, pp. 1-4, 1997. Vol. 1, no. 1, pp. 9-17, 2000. [16] M. Raissy. Determination of Mercury in Some Freshwater Fish [3] M. Dural, M. Z. Lugal Göksu and A. A. Özak. Investigation of Species from Chahrmahal va Bakhtyari Province, Iran and heavy metal levels in economically important fish species Potential Limits for Human Consumption. Bull. Environ. captured from the Tuzla lagoon. Food. Chem. Vol. 102, no. 1, Contam. Toxicol. Vol. 91, no. 6, pp. 667-672, 2013. pp. 415-421, 2007. [17] M. Jalilian, A. Dadollahi-Sohrab and Y. Nikpour. Distribution [4] Oze, R., C. Oze, C.Anunuso, H.N.Ogukwe, and K. Okorie. and contamination of mercury in Metapenaeus affinis shrimp Heavy Metal Pollution of Fish of Qua-Iboe River Estuary: and sediments from Musa Creek (Northwestern part of the Possible Implications for Neurotoxicity. Internet. J. Persian Gulf), I.R Iran. World J Fish Mar Sci. vol. 3, no. 3, pp. Toxicol. Vol. 3, no. 1, pp. 56-59, 2006. 227-231, 2011. [5] M. Raissy, M. Ansari. Health risk assessment of mercury and [18] A. H. Bou-Olayan, S. AI-Yakoob and M. AI-Hossaini. arsenic associated with consumption of fish from the Persian Arsenic in Shrimp from Kuwait. Bull Environ Contam Toxicol. Gulf. Environ. Monit. Ass. Vol. 186, no. 2, pp. 1235-1240, Vol. 54, no. 4, pp. 584-590, 1995. 2014. [19] A. Motallebi. Determination of mercury and lead in Indian [6] J. L. Culioli, S. Calendini, C. Mori, and A. Orsini. Arsenic Shrimp (Penaeus indicus) in Iran. Iran Sci Fish J. vol. 13, no. 3, accumulation in a freshwater fish living in a contaminated river pp. 159-166, 2005. of Corsica, France. Ecotoxicol. Environ. Saf. Vol. 72, no. 5, [20] O. Ozden. Seasonal differences in the trace metal and pp.1440-1445, 2009. macrominerals in shrimp (Parapenaus longirostris) from [7] FAO/WHO. Evaluation of certain food additives and the Marmara Sea. Environ Monit Ass, vol. 162, no. 1-4, pp. contaminants mercury, cadmium and lead. WHO technical 191-199, 2010. report series, No. 505, Geneva, 1972. [21] C. R. Joiris, N. Laroussi Moatemri and L. Holsbeek. Mercury [8] H. Ghorbani. Identification of fishes in important rivers of and Polychlorinated Biphenyls in Zooplankton and Shrimp Chaharmahal & Bakhtyari province (Kyar, Beheshtabad, from the Barents Sea and the Spitsbergen Area. Bull Environ Armad and Khersan), Research center of Animals, pp. 44-48, Contam Toxicol. Vol. 59, no. 3, pp. 472-478, 1997. 1999.

Proceedings of The IRES 15th International Conference, Spain, Barcelona, 14th November 2015, ISBN: 978-93-85832-37-6 21 Determination of Mercury in Fish From Dopoulan River [22] S. A. Rahman, A. K. Wood and S. A. Sarmani, A. Majid. organs of Chalcalburnus chalcalburnus from Anzali Lagoon. J Determination of mercury and organic mercury contents in Mar Sci Technol Res. Vol. 5, no. 9, pp. 23-31, 2005. Malaysian seafood. J Rad Nucr Chem. Vol. 217, no. 1, pp. [26] R. Forooghi, A. Esmaeeli Sari. and M. Ghasempoori. 53-56, 1997. Comparison of correlation of length and weight with mercury [23] M. Khoshnamvand, Sh. kaboodvandpoor, F. Ghiasi and content in different organs of Rutilus frisii kutum from central Bahramnejad B. Comparison of Bioaccumulation of total coasts of south Caspian Sea. Iran J Fish Sci. vol. 15, no. 4, mercury in the meat of Cyprinus carpio and pp.97-102, 2006. Hypophthalmichthys molitrix from Sanandaj Gheshlagh dam. [27] M. S. Hutcheson and C. M. Smith. Freshwater Fish Mercury Environ. Vol. 36, no. 2, pp. 47-54, 2010. Concentrations in a Regionally High Mercury Deposition [24] L. Taheri Azad, A. Esmaeeli Sari and K. Rezaee Tavabe. Area. Water Air Soil Poll. Vol. 191, no. 8, pp.15-31, 2008. Determination of mercury in different tissues of Sander [28] C. Neil, M. Neil, T. Charles, A. Howard, G. Wing, L. Janice, R. lucioperca from the Caspian Sea. Iran J Fish Sci. vol. 17, no. 6, Estabrook, M. Hutcheson, A. Major, A. M. Scheuhammer and pp. 34-38, 2008. D. A. Scruton. Mercury in Freshwater Fish of Northeast North [25] Gh Zolfaghari, A. Esmaeeli Sari, M. Ghasempoori, F. America-A Geographic Perspective Based on Fish Tissue Ghorbani, N. Ahmadifar and Z. Shokri. The relation between Monitoring Databases. Ecotoxicol. Vol. 14, no. 2, pp. 163-180, age, sex and weight with mercury concentration in different 2005.



Proceedings of The IRES 15th International Conference, Spain, Barcelona, 14th November 2015, ISBN: 978-93-85832-37-6 22