Phytofiltration by Aquatic Moss Rids Water of Arsenic rendering it Potable
A commonly occurring toxic element in drinking water is Arsenic- which swirls in a dark, metalloid shimmer in soil and rock across most countries. It seeps into groundwater, but because the contamination tends to be minor in this country, for many years its presence was mostly noted and dismissed by public health researchers.
Chronic low-dose exposure of arsenic has been implicated not only in respiratory problems in children and adults, but in cardiovascular disease, diabetes and cancers of the skin, bladder and lung.
Trace amounts in the body interfere with tumor-suppressing glucocorticoid hormones, studies show, which is one reason that arsenic exposure has been linked to a range of malignancies. Arsenic also interferes with the normal function of immune cells. It damages lung cells and causes inflammation of cells in the heart.
Now, a moss capable of removing arsenic from contaminated water has been discovered by researchers from Stockholm University. And it happens quickly – in just one hour, the arsenic level is so low that the water is no longer harmful for people to drink.
“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.“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, who has conducted the experiments.
The aquatic moss Warnstofia fluitans, which grows in northern Sweden, has the ability to quickly absorb and adsorb arsenic from water. The discovery allows for an environmentally friendly way to purify water of arsenic. One possible scenario is to grow the moss in streams and other watercourses with high levels of arsenic.
The research centres around the ability of the moss to perform a process called phytofiltration, in which waste products such as heavy metals like arsenic are largely absorbed.
To test it in a controlled lab setting (that’s science-ese for “no one has tested this in the field yet,”) the researchers started with water that contained ten times the amount of arsenic deemed safe by the Environmental Protection Agency. When they exposed the moss to it, the moss took just an hour to absorb 82 percent of the arsenic.
But further tests showed that higher concentrations of arsenic, plus mixing in other miscellaneous compounds, slowed down the filtration process. That’s a bit closer to real-world conditions, so that lab ideal would be far from how this moss performs in an actual arsenic-contaminated wetland. But even so, researchers found that the moss was able to tolerate arsenic concentrations 1,000 times higher than the EPA’s maximum before it showed any signs of toxicity itself.
“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.
