Last year, after 15-year-old Katie Vanderwheele read an article about natural arsenic contaminating the drinking water in Bangladesh, she decided that tackling this global problem was a natural fit for a school science project. So she went to Bill Lamb, her science teacher at Oregon Episcopal School in Portland. Gifted students such as Vanderwheele often come to him with ambitious projects – what he calls "Nobel Prize syndrome." In this case, the results of Vanderwheele's research have brought her closer to a Nobel – geographically, at least.
Vanderwheele's project, in which she used water hyacinths to purify arsenic-laced water, earned her $2,500 and the right to represent the US in the Stockholm Junior Water Prize. In August, she'll take a break from her job as a summer camp counselor when ITT Industries sends her to Stockholm to compete with students from more than 30 other countries for the international honor.
As many as 77 million Bangladeshis are at risk for arsenic poisoning, according to the World Health Organization. The Bangladeshi government's standard for arsenic levels in drinking water is 50 ppb, but levels of 300 to 400 ppb are common. Phytoremediation (using plants to remove contaminants) "has been worked on for some time," says Parvez Haris of De Mont-fort University in Leicester, UK, who has published on the topic. Research on removing arsenic with water hyacinths in particular, an easily available and rapidly growing plant in Bangladesh, has shown promise in recent years.
Vanderwheele, who has never been to Bangladesh, says she looked at previous work using hyacinths in phytoremediation and "found some gaps." So she designed experiments to determine how long the same plant could bring arsenic levels down to drinking water standards and to pinpoint where in the plant the arsenic was stored. Neither Vanderwheele's school nor her mother (a former chemist) was enthusiastic about her working with a deadly poison. But Vanderwheele persisted, and the school relented. To test "the way a family in Bangladesh would actually use [the plant]," and to determine how the arsenic affected plant health, she set up a tub of hyacinths in tap water with arsenic levels of 300 ppb alongside a control of hyacinths in regular tap water.
Every day after school for two weeks in January, Katie visited the school greenhouse to check on her plants and to test their water habitats for arsenic. In the first 24 hours, the plants had removed all traces of the chemical. Vanderwheele brought the arsenic level back to 300 ppb on successive days. After the second day, the same plants reduced arsenic levels to the Bangladeshi drinking standard of 50 ppb. The arsenic-exposed plants appeared as healthy as the controls.
On the following three days, the same plants reduced the arsenic level to only 70 ppb, and after five days, they could not remove any arsenic. At that point, she washed, dried, weighed, pureed, and filtered the plants to make water extracts of different sections, and she found that the roots contained more arsenic than the leaves and stems. Though Vanderwheele "was expecting the plants to be able to remove the arsenic for a longer period of time," she says, "it was cool to see it happen."
"The idea is simple but it bears a wide impact," says Mir Misbahuddin, at Banga-bandhu Sheikh Mujib Medical University in Dhaka, Bangladesh, whose own work published in 2002 (
So what's next for this budding water scientist, who also plays junior varsity soccer and varsity tennis and tutors elementary school kids? In the coming months, she hopes to use more stringent methods to test arsenic concentrations in the plants and to run the experiments under conditions closer to those in Bangladesh. She's considering a career in water science and is involved in a local watershed community group. In the meantime, Vanderwheele is excited about the international competition, where she'll meet the top scientists in water quality." It's gonna be really cool."