Hazard identification of coal fly ash leachate using a battery of cyto-genotoxic and biochemical tests in Allium cepa

ABSTRACT

Leaching of heavy metals from coal fly ash dumpsites is an environmental threat often polluting both groundwater and surface water. This led to a detailed investigation on the cyto-genotoxicity and oxidative stress associated with the fly ash leachate (FL). Allium cepa L. bulbs were exposed to three concentrations of FL. Response to FL resulted in a reduction of root growth, inhibition of cell viability by up to 50%, and decrease in mitotic indices (control: 10.27; FA:water 1:4–4.52) with increased frequency of chromosome aberrations (5.7 fold) and bi-nucleate cells. Results of comet assay indicated that approximately sixfold increase in genotoxicity of FL was congruent with the endpoints of oxidative stress evaluated. The malondialdehyde content, superoxide dismutase, guaiacol peroxidase and glutathione-S-transferase activities were elevated in the treated plants in a dose dependent manner. The elemental analysis of FL showed the presence of heavy metals like cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), cadmium (Cd), nickel (Ni), lead (Pb) and zinc (Zn). The study demonstrated that FL can cause adverse effects to the plants. Therefore, the disposal of coal fly ash should be handled with caution and prevented from contaminating the surroundings.

KEYWORDS:

• Fly ash leachate
• cytotoxicity
• DNA damage
• oxidative stress
• catalase
• peroxidase

Acknowledgements

The authors would like to acknowledge the University Grants Commission, New Delhi, for granting RFSMS [Research Fellowship in Sciences for Meritorious Students] fellowship [Sanction no. F. 5-21/2007 (BSR) 2005-06]. Authors would also like to acknowledge DST-PURSE. The authors would like to thank Dr. Lal Chand Ram, Central Institute of Mining and Fuel Research, Dhanbad, for providing fly ash sample.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors would like to acknowledge the University Grants Commission, New Delhi, for granting RFSMS [Research Fellowship in Sciences for Meritorious Students] fellowship [Sanction no. F. 5-21/2007 (BSR) 2005-06].