Methyl mercury in fish—a case study on various samples collected from Ganges river at West Bengal
- 611 Downloads
This study investigated the presence of total mercury (Hg) and organic mercury levels in the muscle of 19 common fresh water fish species captured from river Ganges, West Bengal, India. The total mercury level found in our study may not cause any toxic effect, but the methyl mercury (MeHg) level in some freshwater fish species was surprisingly very high and toxically unacceptable. The results of mercury analysis in various specimens indicated that some fish muscles tended to accumulate high levels of Hg, and approximately 50–84% of Hg was organic mercury. A strong positive correlation between mercury levels in muscle with food habit and fish length (age) was found. Wallago attu possessed the highest amount of organic mercury in their muscle tissues, and it was 0.93 ± 0.61 μg Hg/g of wet weight. Whereas in small-sized fishes Eutropiichthys murius, Puntius sarana, Cirrhinus mrigala, Mystus vittatus or Mystus gulio, and Tilapia mossambicus, it was below the detection limit. Contamination in Catla catla (0.32 ± 0.11), Anguilla bengalensis bengalensis (0.26 ± 0.07 μg Hg/g), Chitala chitala (0.25 ± 0.18), Rita rita (0.34 ± 0.14), and Ompok pabda (0.26 ± 0.04) was also above the 0.25 μg Hg/g of wet weight, the limit set by the PFA for the maximum level for consumption of fish exposed to MeHg. Though in Labeo rohita (0.12 ± 0.03), Mastacembelus armatus (0.17 ± 0.02), Pangasius pangasius (0.12 ± 0.16), Bagarius bagarius (0.12 ± 0.01), and Clupisoma garua (0.1 ± 0.01), concentration was below the recommended level, in Lates calcarifer (0.23 ± 0.0) and Mystus aor (0.23 ± 0.1), it was threatening. Interestingly, a low concentration of Hg was found in post-monsoon samples.
KeywordsBioaccumulation Mercury Methyl mercury Freshwater fish Ganges river
- ATSDR. (2003). Mercury. Agency for toxic substances and disease registry. GA: US. Department of health and human services, public health services, Atlanta. http://www.atsdr.cdc.gov/ToxProfiles/tp46-c5.pdf. Accessed 15 Nov 2010.
- Ben-Ozer, E. Y., Rosenspire, A. J., McCabe, M. J., Worth, R. G., Kinzelskii, A. L., Warra, N. S., et al. (2000). Mercuric chloride damages cellular DNA by a non-apoptotic mechanism. Mutatation Research, 470, 19–27.Google Scholar
- Darnton-Hill, I., Hassan, N., Karim, R., & Duthie, M. R. (1988). Tables of nutrient composition of Bangladeshi foods. English version with particular emphasis on vitamin A content. Dhaka: Helen Keller International.Google Scholar
- Felton, J. S., Kahn, E., Salick, B., van Natta, F. C., & Whitehouse, M. W. (1972). Heavy metal poisoning: mercury and lead. Annals of Internal Medicine, 76, 779–792.Google Scholar
- Glockling, F., Hosmane, N. S., Mahale, V. B., Swindall, J. J., Magos, L., & King, T. L. (1977). Mono, bis-, and tris-(trimethylsilyl)methyl derivatives of mercury. Journal of Chemical Research, 116, 1201–1256.Google Scholar
- Horwitz, W. (2000). Official methods of analysis of AOAC International, vols. 1 and 2 (17th ed.). Gaithersburg: AOAC International.Google Scholar
- IRIS- Integrated Risk Information System. (1993). EPA. Washington, DC: Office of Research and Development.Google Scholar
- Lebel, J., Mergler, D., Lucotte, M., Amorim, M., Dolbec, J., Miranda, D., et al. (1996). Evidence of early nervous system dysfunction in Amazonian populations exposed to low levels of methylmercury. Neurotoxicology, 7, 157–167.Google Scholar
- Maršálek, P., & Svobodová, Z. (2006). Rapid determination of methylmercury in fish tissues. Czech Journal of Food Science, 24, 138–142.Google Scholar
- Moszczynski, P., & Moszczynski, P. (1990). Current views on biotransformation and metabolism of mercury (in Polish). Postȩpy Higieny i Medycyny Doświadczalnej, 44, 153–180.Google Scholar
- Rutowski, J., Moszczynski, P., Bem, S., & Szewczyk, A. (1998). Efficacy of urine determination of early renal damage markers for nephrotoxicity monitoring during occupational exposure to mercury vapor. Medycyna Pracy, 49, 129–135.Google Scholar
- Sinha, R. K., Sinha, S. K., Kedia, D. K., Kumari, A., Rani, N., Sharma, G., et al. (2007). A holistic study on mercury pollution in the Ganga river system at Varanasi, India. Current Science, 92(9), 1223–1227.Google Scholar
- The Prevention of Food Adulteration Act (1954). Together with prevention of adulteration rules, (1955) and notification and commodity index, India (amended, 2002). Lucknow: Eastern Book Company. Table No. R-57, 106–110.Google Scholar
- U.S. EPA. (1992). National study of chemical residues in fish. WH-551, vol. I. Washington, DC: Office of Science and Technology.Google Scholar
- US EPA. (2001). Water quality criterion for the protection of human health: methylmercury. Final report EPA-823-R-01-001. Washington, DC: US EPA. http://www.epa.gov/waterscience/criteria/methylmercury/document.html. Accessed 15 Aug 2003.
- World Health Organization. (1990). Environmental health criteria 101: methylmercury. Geneva: World Health Organization. http://www.americanchronicle.com/articles/view/109078.Google Scholar