Photo by katerha via Flickr CC
When we think of plastic bottles, we usually think of them as a serious problem tied up with our drinking water, not a possible solution for cleaning water for 100 million people. But researchers have found that by combining cut-up plastic bottles with a nutrient found in dietary supplements, water contaminated by arsenic can be made clean enough to drink.
American Chemical Society reports that almost 100 million people in developing countries areexposed to dangerously high levels of arsenic in their drinking water. But this new technology could help as a simple, inexpensive and very easy to use solution.
"Dealing with arsenic contamination of drinking water in the developing world requires simple technology based on locally available materials," said study leader Tsanangurayi Tongesayi, Ph.D., professor of analytical and environmental chemistry at Monmouth University, West Long Branch, N.J. "Our process uses pieces of plastic water, soda pop and other beverage bottles. Coat the pieces with cysteine -- that's an amino acid found in dietary supplements and foods -- and stir the plastic in arsenic-contaminated water. This works like a magnet. The cysteine binds up the arsenic. Remove the plastic and you have drinkable water."
In tests, the strategy was used in water containing 20 parts per billion (twice the US EPA safety standard) and bind enough arsenic to produce water of just 0.2 ppb.
Plastic bottles are ubiquitous and can be gathered locally, and adding the cysteineis a non-technical process, so essentially anyone in any village would be able to provide nearly arsenic-free water to residents.
Arsenic in the water is an increasing problem as groundwater sources are over-exploited, and researchers are working hard to discover where arsenic is most prevalent in water supplies. From Bangladesh and areas of Southeast Asia, to even the US, as we drill deeper for water we come up with contamination. Knowing where arsenic is a problem is step one, while step two is finding cheap, simple solutions for removing it.
The technology developed by Tongesayi sounds promising, though using plastic in such a way may have its own ill effects. Another possible technology for removing arsenic utilizes a more natural substance - cattails.
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