Seasonal Variation Of Heavy Metal Accumulation In Water And Fish Tilapia mossambicus Collected From Puliyanthangal And Maniyambattu Lake Of Ranipet District, Tamilnadu.

Abstract

The purpose of the study to evaluate the seasonal variation of heavy metal accumulation of lead (Pb) and chromium (Cr) in water and selected tissues such as gill, liver, muscle and ovary of the  Tilapia mossambicus collected during the year between  2015 and 2016 at Puliyanthangal (PS1) and Maniyambattu Lakes (MS1) of Ranipet during the pre-monsoon, monsoon and post-monsoon seasons. Accumulation of heavy metals in water and fish samples was determined using atomic absorption spectrophotometry (AAS). Among the lead (Pb) and chromium(Cr) analyzed during a different season, the level of Pb and Cr concentration in S₁ and S₂ at Puliyanthangal lake (PS1)  and Maniyambattu Lake water (MS1) were above the permissible limit of 0.05 and 0.01 prescribed by drinking purpose (WHO). The heavy metal concentration of lead (Pb) and chromium (Cr) in the Mouth region (S₁) seemed to be higher than the middle region (S₂) at PS1 and MS1.  Results showed that the seasonal mean value of lead (Pb)  in PS1 and MS1 were within the acceptable limit by international standards complied by FAO. The level of chromium (Cr) concentration in PS1 and MS1 higher than the permissible limit except for Cr content in muscle at PS1, which was within the acceptable limit. In Puliyanthangal lake (PS1), the lead (Pb) and chromium (Cr) content during different seasons showed the order gill>liver>ovary>muscle and liver>gill>ovary>muscle. In Maniyambattu Lake (MS1), the lead (Pb) content showed the order: liver>gill>ovary>muscle in monsoon and post-monsoon season and gill>liver>ovary>muscle in pre-monsoon season and chromium (Cr) concentration showed the order :liver>gill>muscle>ovary in the pre-monsoon season, gill>liver>ovary>muscle in monsoon and post-monsoon.Statistical analysis of Pb and Cr concentration in water and fish tissues among the seasons and between the sites significantly differed at p>0.05. Bioaccumulation of Pb and Cr was found more in gill and liver tissues than other organs because gill remains close contact with the environment. The liver plays a vital role in metal sequestration. The study concluded that Pb and Cr were found predominant in the tissues gill and liver with fluctuation of their level among the seasons.