Journal of Research in Environmental Science and Toxicology (ISSN: 2315-5698) Vol. 6(1) pp. 008-011,  May 2017. DOI: http:/ Copyright © 2017 International Research Journals


Full Length Research Paper

Toxic stress exhibited by juveniles of Clarias gariepinus exposed to different concentration of lead

*Azua E.T and Akaahan T. J

Department of Biological Sciences Federal University of Agriculture Makurdi, P.M.B. 2373 Makurdi Benue state Nigeria

*Corresponding Author’s

Received April 15, 2017;  Accepted May 10, 2017



The toxic stress of lead exposed to Clarias garienpinus was determined at 96-hour. Anhydrous Lead II nitrate was used to prepare the stock solution. The concentrations of lead used were: 0.00, 1.80, 3.20, 5.60, and 10.60mg/L. The lethal concentration (LC50) was estimated using the logarithmic method and was found to be5.60mg/L. The lethal concentration confirmed that lead II nitrate is highly toxic to Clarias garienpinus. The Fish showed various abnormal behaviors upon exposure to lead II nitrate, immediate reaction was erratic swimming and tendency to jump out of the test bowl. Others include restlessness, uncoordinated movement, vertical swimming, air gulping, loss of equilibrium, a period of quiescence and eventually death. There is need for more work to set maximum permissible levels of metals for fish meant for human consumption in Nigeria.


Keywords: Toxic stress, Lead, Clarias garienpinus.

The present study investigated the polycyclic aromatic hydrocarbon (PAH) contents of farm soils and three commonly consumed vegetables grown in farmlands in two communities- Alakahia and Eleme, Rivers state, Nigeria and their potential impacts on human health. The total PAH concentrations in vegetables and soil ranged from 1.34 to 9.51 and 51.02 to 93.14 µg/kg, respectively. Samples from the Eleme community had higher PAH concentration than samples from Alakahia community. Pyrene and Fluoranthene were the predominant PAH in the farm soil samples from Alakahia and Eleme respectively. The profile of PAH in the vegetable samples were dissimilar at both communities when compared to the farm soil samples. The Low molecular weight PAH to High molecular weight PAH ratio (LMW-PAH/HMW-PAH) showed that the high molecular PAH were predominant in the Alakahia farm soil while the low molecular PAH dominated the Eleme soil sample. The carcinogenic Potency equivalent concentration (µg/kg) were estimated to be 0.31- 1.51 and 0.37 - 0.97 for vegetablescollected from Alakahia and Eleme communities respectively. These values exceeded the screening value (0.23) for vegetables, thus indicating that the consumption of such vegetables is risky for the exposed population.


Keywords: PAH, Vegetables, Rivers state, Health risk, Carcinogenic.