Seasonal Variation in Occurrence of Heavy Metals in Perna Viridis from Manora Channel of Karachi, Arabian Sea  

Qari Rashida.1 , Ajiboye Olufemi.2 , Manzoor Rana.1 , Afridi Abdul Rahim.3.
1. Institute of Marine Science, University of Karachi, Karachi 75270, Pakistan
2. Nigerian Institute for Oceanography and Marine Research, Sapele station, PMB 4015, Sapele, Delta State, Nigeria
3. Centre of Excellence in Marine Biology, University of Karachi, Karachi 75270, Pakistan
Author    Correspondence author
International Journal of Marine Science, 2015, Vol. 5, No. 45   doi: 10.5376/ijms.2015.05.0045
Received: 30 Apr., 2015    Accepted: 31 May, 2015    Published: 26 Jul., 2015
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This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Qari Rashida., Ajiboye Olufemi., Manzoor Rana and Afridi Abdul Rahim., 2015, Seasonal Variation in Occurrence of Heavy Metals in Perna Viridis from Manora Channel of Karachi, Arabian Sea, International Journal of Marine Science, 5(45): 1-13 (doi: 10.5376/ijms.2015.05.0045)


Seasonal sampling of the edible green mussel Perna viridis of two different sizes 6-8cm (n=100) and 4-6cm (n=100) from Manora channel of Karachi, were analyzed for their total Hg, Pb, Cu, Ni, Zn, Co, Fe, Cr, Cd and Mn concentration.  There are large seasonal variations in the metal concentrations found in green mussel Perna viridis. The high accumulations of metals were found mostly in small size 4-6 cm mussels as compare to largeones. The present study has confirmed thatgreen mussels have greater capacity for accumulation ofmetals.All the studied metal levels found in green mussels collected in 2012 were higher than those detected in mussels collected in 1993, irrespective of mussel body size. The concentrations of Fe was highest compared to other heavy metals. The results of heavy metals are in the following descending order of concentration: Fe>Pb> Zn>Cu>Mn> Ni> Cr> Cd> Co> Hg. It is supposed that in Manora channel water, high input of metals and other inorganic and organic substances are coming in the form of industrial and domestic wastes and need to be monitored on a regular basis.

Heavy metals; Green mussel; Accumulation; Pollution

1 Introduction
The green mussel Perna viridis had been known as a good biological indicator for heavy metals concentration by many researchers (Khan et al., 2015; Ali et al., 2014; Putri et al., 2012; Widmeyer and Bendell-Young, 2007; Yap et al., 2002; Sivalingham, 1977). From the literature, the heavy metal concentrations measured in the soft tissues of mussels could be used as biomonitors of heavy metal bioavailabilities and contamination in the coastal environment, in which the mussels live (Yap et al., 2006). The mussel species have been widely used in pollution monitoring programs such as ‘mussels watch’ program. It is an ecologically and economically important bivalve with outstanding potential as sentinel organism.

The green mussel fulfills the important criteria to be a good biomonitoring agent for heavy metal pollution studies in the coastal waters because of its wide geographical distribution, sedentary lifestyle, easy sampling and identification, availability throughout the year, capacity to accumulate pollutants in their tissues, tolerance but relative sensitivity to chemical pollutants and commercially important protein source (Yap et al., 2004).Due to its stress tolerant capacity and ability to accumulate pollutants in their tissues, present research work focused on determination of essential and non-essential heavy metals such as Hg, Pb, Cu, Ni, Zn, Co, Fe, Cr, Cd and Mn concentrations in the soft tissue of common bivalve (P. viridis) which were collected from the Manora channel of Karachi, Arabian Sea, Pakistan. However, the concentration of heavy metals accumulated by marine organisms are not only depending on the water quality but also seasonal factor, temperature, salinity, diet or food intake, spawning and individual variation (Hamed and Emara, 2006). On the other hand, periodical evaluation of heavy metals level in the tissues of organisms and water from expected polluted area are of major importance (Ali et al., 2014; Yap et al., 2009; Aktan and Tekin-Özan, 2012; Kock and Hofer, 1998)

The metal pollution in the ocean is a major problem that is directly affecting the marine life and indirectly affects human health and resources (Qari and Siddiqui, 2008). Karachi, being the natural seaport and the largest industrial city of Pakistan, located in the north eastern border of the ArabiaSea, lying between latitudes 24o48´ N and 66o59´ E longitude (Ashraf et al., 1992). The port and several industries are located in the Karachi city. Untreated or partially treated industrial and domestic waste waters are discharged directly or c

International Journal of Marine Science
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