Identification of a Biochemical Indicator in Plants for Heavy Metal Contamination

Aims: To identify a biochemical parameter in a plant(s) that can serve as an indicator of heavy metal pollution.

Study Design: Design of the study includes collection of plant samples from a contaminated site and a rural site and to check their biochemical parameters related to oxidative stress. Based on the experimental findings, attempts were made to identify a parameter that can serve as an indicator of heavy metal contamination.

Place and Duration of Study: The study was conducted in Department of Biotechnology, Heritage Institute of Technology, India, during the period from August 2013-June 2014.

Methodology: Plant samples were collected from East Calcutta Wetlands (metal contaminated site) and Binogram, a village 90 Km away from Kolkata (control site). The samples were checked for the following parameters: non-protein thiol, ascorbic acid, superoxide dismutase (SOD), lipid peroxidation. This was followed by a statistical analysis.

Results: Non-protein thiol content was found to be less in the Ipomoea, Hygrophila and cabbage samples collected from ECW. The values were 65-75% of the village samples. Cauliflower leaves did not show any alteration in the parameter. Ascorbic acid was altered significantly in cabbage and Hygrophila. Activity of SOD decreased in all samples. Lipid peroxidation increased in all samples except Ipomoea. Of the biochemical parameters tested, maximum alteration was found with non-protein thiol, in which glutathione (GSH) is the major constituent. Of the vegetables studied, cabbage showed an alteration in all biochemical parameters.

Conclusion: GSH has the potential for being used as an indicator of heavy metal pollution. Cabbage can be used as a model vegetable for testing the biochemical parameters. The method will be helpful in identification of a contaminated site before estimation of heavy metals.