Coriander or cilantro, the leafy herb lavishly used to garnish a wide variety of everyday Indian cuisine has started attaining fame in the United States as a possible low cost herbal remedy to purify drinking water. A recent research has discovered that the leaves of the coriander are a potential “biosorbant” that can remove lead and other toxic heavy metals from contaminated water.

Possessing a flavour that everyone savours, US based researchers say that the coriander leaf (Dhaniya in Hindi, Kothamalli in Tamil and Malayalam) “has the ability to drink up heavy metals like lead and nickel that have leaked into ground water”. Studies are continuing to learn how well the herb can remove other heavy metals such as arsenic and mercury.

The discovery was presented on September 12 at the 246th annual National Meeting and Exposition of the American Chemical Society (ACS) by scientist Douglas Schauer of Ivy Tech Community College Indiana US who led a research team to Mexico to find low cost materials that could filter away industrial pollutants in ground water.

Cilantro is also a commonly used cooking herb in Mexico which also has a serious ground water pollution problem, Professor Schauer said. “Our hope is for somebody who lives in such regions to simply be able to go in their back yard and grab a handful of cilantro, maybe let it dry out for a couple days sitting on a rock in the sun, and then maybe a handful of that would purify a pitcher of water”.

He also believes that dried cilantro could someday be packaged like tea bags, or as reusable water-filter cartridges to remove heavy metals from impure water. The research report has been published by ACS. Professor Schauer said that a handful of cilantro will neatly filter away lead from a pot full of highly contaminated water.

He said that the secret to cilantro’s purifying power lies in the structure of the outer walls of the microscopic cells that make up the leaves. The architecture of these walls makes them ideal for absorbing heavy metals. On the basis of the finding the Voice of America in September 29 “Learning English Newsletter” described coriander as a “miracle herb”.

Though activated carbon is the most popular material used in water purifiers, it is too expensive for most developing countries. Professor Schauer says that coriander is an inexpensive way to purify drinking water. Coriander is not only cheaply available but also available in plenty, he said.

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