Olagunju  T.E.¹ , Adeboye  T.A.² , Kachi  J.B.³ , Opasola  O.A.⁴

1. Ecology and Environmental Biology Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria.
2. Department of Chemistry, University of Ibadan, Ibadan, Nigeria.
3. Department of Biological Sciences, Federal University of Lokola, Lokoja, Nigeria.
4. Department of Environmental Toxicology and Management, Kwara State University, Malete, Nigeria.
Author    Correspondence author
International Journal of Aquaculture, 2015, Vol. 5, No. 28   doi: 10.5376/ija.2015.05.0028
Received: 15 Jul., 2015    Accepted: 18 Aug., 2015    Published: 30 Sep., 2015

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.

Olagunju, T.E., Adeboye T.A., Kachi J.B., and Opasola O.A., 2015, The Relationship between Exposure Period, Body Size and Bioconcentration of Heavy Metals in Clarias gariepinus, International Journal of Aquaculture, 5(28): 1-5

Heavy metals have continued to be pollutants of concern due to their persistence in the environment and effects on the organisms. The relationship between the exposure period, body size (length) and bioconcentration of heavy metals in Clarias gariepinus were investigated. The fish were exposed to 5 mg/L sublethal concentration of combined metal solution of analytical graded cadmium chloride, lead nitrate, potassium chromate and hydrated copper sulphate for 21 days. The result obtained indicates that the concentrations of the heavy metals increase with the exposure period up to a point followed by uniform/constant levels. Inverse relationship was recorded between the metal concentration in the fish and the body size (length) of the fish. The trend of heavy metal concentration in the body tissue of the fish was Pb>Cu>Cr>Cd. It is suggestive that on the long run, fish may develop regulatory processes when exposed to sublethal dose of a toxicant in other to adjust to the new condition and that the high metabolic activities in young fish may be responsible for the high metal concentration in their tissues. Hence, it is therefore important to put into consideration exposure period and body size during a biological assay for proper interpretation and understanding of the effects of a toxicant.

Exposure period; Body size; Beavy metal; Clarias gariepinus