Toxicological Assessment of Arsenic-Induced Hematological Alterations and Chromosomal Aberrations in Tilapia Oreochromis mossambicus

ABSTRACT

Arsenic is an environmental contaminant and potential carcinogen. Toxicological assessment of As, which causes hematological alterations and chromosomal aberrations, was studied in freshwater fish Oreochromis mossambicus. Fish were exposed to 3 ppm, 28 ppm, and 56 ppm concentrations of sodium arsenite (NaAsO₂) and blood samples were collected after 48 h, 96 h, and 192 h of exposure. Hematological assay of exposed fish revealed abnormal mature and immature erythrocytes, deformed erythrocytes (spindle-shaped and triangular erythrocytes) and erythrocytes with segmented nuclei in all treatments. Arsenic exposure induced chromosomal aberration in a concentration-dependent manner, whereas, a decreasing trend was found after 192 h exposure. Observations on blood cells of exposed fish revealed chromosome breaks, chromatid breaks, and chromatid gaps. The alterations and aberrations of these parameters can be effectively used to assess toxicological effects of As on fish in the aquatic environment and at the same time this study elucidates the potential risks to humans who live in arsenic-contaminated areas.

Key Words:

• toxicology
• arsenic
• Oreochromis mossambicus
• hematology
• chromosomal aberration

ACKNOWLEDGMENTS

We thank Professor Anwar Hossain, Department of Biochemistry, University of Dhaka for providing the laboratory facilities. In this study the fish as experimental animals were used following the ethical guidelines and upon the approval of the committee for biosafety of the University of Dhaka.