An environmental and civil engineer has developed an inexpensive arsenic filtration system that uses aquatic plants, namely cattails, to remove poisonous arsenic from drinking water, which could improve the health of millions in countries around the world whose local water supplies are naturally contaminated with the toxic substance. An estimated 57 million people are drinking groundwater with arsenic concentrations measured above the World Health Organization‘s standard of 10 parts per billion.
Jeremiah D. Jackson, Ph.D., P.E., of San Diego, CA, says he started his research after his brother, a journalist, mentioned the dire need for filtering the arsenic from groundwater in countries such as India, Pakistan, Mexico, and even parts of rural U.S. Arsenic-contaminated water is responsible for epidemics of arsenicosis (chronic arsenic poisoning from drinking water) in Bangladesh, and a cheap effective filtration system could save millions of lives each year.
Jackson set up an experiment on his patio, with cattails planted in sand in five-gallon buckets filled with water. Some were left untreated, and others were dosed with various concentrations of arsenic. After measuring the arsenic removed by the cattails, he felt justified in building a prototype in a wading pool, with the guiding principles of no moving parts, low cost to build, and to be easily constructed by a layperson.
He ran the experiment for about six weeks, and found that it resulted in an 89% removal of arsenic to about 37 micrograms per liter, a level below the world health standard of 50 micrograms per liter.
“The cattail actually thinks the arsenic is a nutrient. It absorbs it as if were a nutrient, a fertilizer. And I found the plants actually flourished.”
By his calculations, a system like his would cost a family about 21 cents per 1,000 gallons of treated water (compared to more complex technologies costing from $50 to $300 per 1,000 gallons). He believes the cattails can absorb the arsenic for up to 50 years but suggests they just decommission the device every ten years.
Jackson’s research was published in the April 2007 issue of Civil Engineering Magazine in a special section, the Arsenic Crisis.