Amid growing concerns regarding the safety of our drinking water, new research suggests a favorite ingredient in Mexican, Southeast Asian and other spicy food may help. Cilantro – also known as coriander and Thai parsley – shows promise as a new, much needed “biosorbent” for removing toxic heavy metals from contaminated water.
Douglas Schauer, PH.D, and several students at Ivy Tech Community College worked with scientists at the Universidad Politécnica de Francisco I. Madero in Hidalgo, Mexico to make the discovery. Their research suggested that cilantro may be more effective than activated carbon in removing heavy metal toxins such as lead.
Conventional Methods More Expensive
Conventional methods for removing heavy metals from water include the activated carbon filters commonly used in many American homes. There are also more advanced technologies like ion-exchange resins. Both are very effective, but they can be too expensive for use in developing countries – especially in rural areas. The need for lower-cost, sustainable alternatives has driven research in biosorbents.
“Cilantro may seem too pricey for use in decontaminating large amounts of water for drinking and cooking,” Schauer said. “However, cilantro grows wild in vast amounts in countries that have problems with heavy metal water pollution. It is readily available, inexpensive and shows promise in removing certain metals, such as lead, copper and mercury – all of which can be harmful to human health.”
Natural and Free
Mexico is one of numerous countries that do not have adequate systems to filter out heavy metals. Cilantro grows wild there, however, and may be a less expensive option. “Our goal is to find biosorbents that people in developing countries could obtain for nothing,” Schauer explained. “When the filter in a water purification pitcher needs to be changed, they could go outside, gather a handful of cilantro or some other plant, and presto, there’s a new filter ready to purify the water.”
Natural biosorbants, which range from microbes to plants, latch on to heavy metals in ways that include both absorption and adsorption. Where absorption involves filling the pore of a porous object, adsorption involves the binding of molecules or particles to an object’s surface.
Cilantro’s ability to remove toxins from water may lie in the structure of the outer walls of the cells that make up the plant. They have an architecture ideal for both absorption and adsorption of heavy metals. Other plants, including cilantro’s cousins, parsley and culantro, have similar features and could potentially work as biosorbents. Schauer thinks that biosorbents like cilantro could be packed into reusable water filter cartridges, tea-bag-like packets or tea infuser balls.
Dr. Schauer presented his findings at the 246th National Meeting & Exposition of the American Chemical Society.