Miracle moss removes arsenic from drinking water

moss
© Arifin Sandhi

The aquatic moss clears 80 percent of arsenic from a container of water in less than an hour.

While it's not the responsibility of plants to clean up the mess we humans seem to make of the planet, it is certainly kind of them to show us how it's done. The latest plant to offer an assist in environmental clean-up looks to be Warnstofia fluitans, otherwise known as floating hook moss.

That the moss was found capable of removing arsenic from contaminated water was discovered by researchers from Stockholm University. They concluded that in just one hour of filtering, arsenic levels were so low that the water was safe for drinking.

"Our experiments show that the moss has a very high capacity to remove arsenic. It takes no more than an hour to remove 80 per cent of the arsenic from a container of water. By then, the water has reached such a low level of arsenic that it is no longer harmful to people," says research assistant Arifin Sandhi.

The moss purifies by quickly absorbing and adsorbing (in which something sticks to the surface, basically) arsenic from water. The discovery could easily pave the way for an eco-friendly way to purify water. One possible scenario is to grow the moss in streams and other waterways with high levels of arsenic, note the researchers.

"We hope that the plant-based wetland system that we are developing will solve the arsenic problem in Sweden's northern mining areas," says Maria Greger, associate professor at the Department of Ecology, Environment and Plant Sciences at Stockholm University and leader of the research group.

Arsenic finds its way into the ground and water systems naturally; but also through industry, now mostly from mining. When arsenic-polluted water is used to irrigate crops, it is absorbed by the plants and ends up in the food chain. In Sweden, wheat, root vegetables, leafy greens, and other crops suffer from this; In many places, rice routinely tests positive for arsenic. Arsenic poisoning is widespread in some countries – for example, an estimated 57 million people in the Bengal basin drink groundwater with arsenic levels above the World Health Organization's standard. In the U.S., arsenic is found in the ground waters of the southwest, parts of New England, Michigan, Wisconsin, Minnesota, the Dakotas, and more are known to have significant concentrations of arsenic in groundwater.

[See more: How to cook rice to remove the most arsenic]

"How much arsenic we consume ultimately depends on how much of these foods we eat, as well as how and where they were grown. Our aim is that the plant-based wetland system we are developing will filter out the arsenic before the water becomes drinking water and irrigation water. That way, the arsenic will not make it into our food," says Maria Greger.

The research was published in the journal Environmental Pollution.

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