Fifty million American homes rest on soil that contains toxic levels of arsenic. Though this deadly element occurs naturally, often released in gaseous volcanic emissions, human activities like pesticide use have magnified its presence.
But for the past few years, scientists and citizens alike have been witnessing the fascinating ability of plants to slurp up and sequester heavy metals like arsenic. The Edenspace Corporation of Dulles, Virginia has brought a tropical Floridian fern to the backyards of many America citizens, who are much safer because of it.
“Edenfern” has a curiously high tolerance for arsenic, so high that it can take up 10,000 times more than other plants without harm. The fern has evolved natural molecules that bind to arsenic and store it in their aboveground leaves, says Edenspace’s molecular biologist, David Lee. Here, the trapped arsenic can’t directly harm humans, and also dissuades hungry insects from munching on the fern.
Villagers in Bangladesh and India face a much more chronic arsenic situation, one that has been more or less neglected. Back in 1996, a few Bangladeshi scientists realized that something strange was happening to many people: they were losing hair, their skin was discolored, their stools showed traces of blood, and there were higher incidences of cancer and premature death.
It turns out that the tube wells that provide villagers with drinking water, or more commonly, “Devil’s water,” are riddled with arsenic, which stealthily blends with the water because it lacks color and taste. Even though the arsenic levels here exceed the World Health Organization limits, many people continue to drink from the wells, mostly because they have no alternative. Lee says that Edenspace hopes to intervene by introducing the advantages of edenfern to both countries.
Using plants as a remedy for environmental problems, an approach called phytoremediation, is very promising and affordable, only requiring solar energy to feed the plant. Many plants take up valuable heavy metals like nickel and zinc that can be recovered and recycled for future use by incinerating the plant material.
But phytoremediaton still hasn’t been deployed on a large scale because the Environmental Protection Agency (EPA) hasn’t authorized it as a standard technique for restoring contaminated sites. One of the downsides is that plants take a year or two to grow and accumulate contaminants, says Lee. “It’s kind of rare when you have the interest in trying to clean up a site but not the urgency of needing to clean it up next week.”
The EPA acknowledges phytoremediation’s effectiveness in greenhouses and pilot experiments, but claims that the process is still too new and therefore unfamiliar. However, with more research to prove its reliability, phytoremediation will most likely be employed on a broader scale.