This study examined the effects of the pesticide endosulfan on biochemical and hematological indices in the amphibian Bufo regularis and the fish Clarias gariepinus. Animals were exposed to sublethal concentrations of endosulfan for 28 days. Results showed increases in glutathione S-transferase and glucose levels and decreases in cortisol, total protein, and red blood cell counts in both species. White blood cell counts also decreased except for neutrophil granulocytes and eosinophils, which increased. The study concluded that glucose levels and white blood cell counts were the most effective biochemical and hematological biomarkers, respectively, for assessing endosulfan toxicity. Biomonitoring pest

1. CSTS/SETAC Africa 2011 Meeting31 May–3 June 2011, University of Buea, Cameroon Alterations in Biochemical and Haematological Indices in Bufo regularis (Amphibian) and Clarias gariepinus (Fish) Exposed to Endosulfan. Presenter: Ogbomida Emmanuel 1Tongo Isioma, 2Ogeleka Doris, 3Ikpesu Thomas, 4Ogbomida Emmanuel, 5Enuneku Alex, 6Ezemonye Lawrence. 1,3 Department of Animal and Environmental Biology (AEB) University of Benin, Benin City 2 Department of Chemistry, Western Delta University, PMB 10, Oghara, Delta State 5Department of Environmental Science, Western Delta University, PMB 10, Oghara, Delta State 4,6 National Centre for Energy and Environment (NCEE), Energy Commission of Nigeria, University of Benin

3. Presence of pesticides in streams and lakes is largely due to the runoff from agricultural fields and outfall from pesticide manufacturing factories (Anandkumar, 1988).

4. Pesticides are not highly selective, up to 90% of the pesticides applied never reach the intended targets; as a result, many other organisms sharing the same environment as pests are accidentally poisoned. These non-target organisms include amphibians (Fulton and Chambers, 1985; Berrillet al., 1994; Sparlinget al., 2001) and fish (Ayoola, 2008; Franklin et al., 2010).

8. Endosulfan is persistence in the environment and has been reported to disrupt endocrine system, causing reproductive and developmental damage in both animal and human (PMRA, 2003).

10. High prolific nature

11. Ease of collection ,transportation, handling and maintenance under laboratory conditions

14. Adult toads, B. regularis of both sexes were collected from their spawning ponds in unpolluted areas in Oghara, Delta State (5°30′N 6°00′E),while juveniles of C.gariepinus of uniform length were collected from Patiby Agro Industrial Enterprise, ErawaOwhe, Delta State, Nigeria.

15. Toad and fish samples were collected with hand net from their natural environment and transported in covered baskets and plastic tank to the Laboratory.

17. Sub lethal concentrations of 0.01, 0.02, 0.03, 0.04 g/l (toad) and 0.00, 0.0025, 0.005, 0.0075, 0.01 g/ l(fish)were prepared by serial dilution of stock solution

18. Alterations in Biochemical and Heamatological parameters in Serum, were used as indices of toxicosis.

21. Determination of AChE activity was adopted from colorimetric procedure of Ellman et al(1961).

22. Glucose level was estimated following the method of Folin-Wu (1926). .

23. Cortisol levels was estimated by the method as described by Barseghian et al.(1982) .

25. The changes in GST activity in the serum increased compared to the control (Figure 1). However, increase in GST activities in the fish was more than that of the toad. Figure 1: Glutathione-S-transferase activity in the serum of C.gariepinus and B. regularis exposed to different concentrations of endosulfan.

26. Acetyl cholinesterase (AChE) No significant changes in activity were observed (P >0.05) for both species (Figure 2). Figure 2: Acetyl cholinesterase (AChE) activity in the serum of C.gariepinus and B. regularis exposed to different concentrations of endosulfan.

29. However, reduction of Cortisol levels in the fish was more than that of the toad (Figure 4). Figure 4: Reduction in Cortisol Levels in serum of C.gariepinus and B. regularis exposed to Endosulfan for 28 days.

31. Reduction of Protein levels in the fish was also more than that of the toad (Figure 5).Figure 5: Reduction in Protein Levels in serum of C.gariepinus and B. regularis exposed to Endosulfan for 28 days.

34. The reduction in White Blood Cell Indices were statistically significant compared with control (P<0.05) for both species.

35. In contrast, there was an increase in Neutrophile granulocytes and Eosinophils when compared with the control. Increase in Neutrophile granulocytes and Eosinophils were also statistically significant compared with control (P<0.05).Figure 7: Alteration in White Blood Cell Indices in C.gariepinus and B. regularis Exposed to Endosulfan for a period of 28 days.

37. Acknowledgement This study was generously supported by the National Centre for Energy and Environment (NCEE) Energy Commission of Nigeria (ECN), University of Benin, Benin City, Research Grant. The technical assistance of members of the thematic group at the centre is highly appreciated.

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