CHENNAI: When you buy the Ponnanganni greens (Alternanthera Sessilis) next time, Beware! The alien species of the much-loved keerai, may pose health hazards.
Speaking to reporters after addressing a discussion on Biodiversity and Invasive Alien Species organised by the CPR Environmental Education Centre here on Friday, Reader, Department of Botany, Madras Christian College, Dr D Narasimhan said of the seven Ponnanganni species, six were alien and only one is the native variety. All species are grown in Tamil Nadu and it is difficult to distinguish the native one from the alien as all the varieties are known by the common name of Ponnanganni.
The source of the alien Ponnanganni is tropical American countries and the trouble with these species is that it is contaminated with heavy metals as it generally grows abundantly around sewage canals and in marshy areas.
“About 90 per cent of the Ponnanganni greens that come to the market is alien and could have toxic elements.” The alien keerai is much leafy, more greener and the stem is fat. Whereas, the native Ponnanganni’s stem is slender, its leaves are smaller and are pale green. “It would be better if the consumers avoid the alien greens as it could pose health hazards,” Narasimhan said. Similarly, ornamental Manjal Karsalanganni (Wedelia) is different from the one that has medicinal properties. Care should be taken to avoid taking the ornamental kind for health purposes.
Avoid alien fish variety: Scientist, Marine Biological Station, Zoological Survey of Inida, K Remadevi said the Corporation of Chennai has been advocating using gambusia fish species to control the mosquito menace. This should be avoided as the alien fish variety could threaten the native ones.
