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SINGAPORE - Fruit peel is used as compost by the environmentally conscious worldwide. But the throwaway item could soon have an even higher calling - saving lives.
Tomato and apple peel act like sponges in polluted water, vastly reducing levels of heavy metals, pesticides and dyes, researchers at the National University of Singapore have found.
Their findings could pave the way for a readily available and low-cost way to make drinking water safer for millions.
This could be especially crucial for those in remote regions without easy access to water purification devices, and where groundwater close to villages is contaminated by industrial pollution, said lead researcher Ramakrishna Mallampati on Thursday.
Nearly 800 million people worldwide do not have access to clean water, according to Unicef. The university's two-year study found, for example, that the peel from eight tomatoes can almost completely remove heavy metal ions such as lead from a litre of water in an hour.
"There are many other products already in the market, but...developing countries cannot afford these costly technologies," said Mr Ramakrishna. Such products include LifeStraw, a personal water filter in the form of a straw that retails for about $25.
Fruit peel, on the other hand, is available throughout the world as a waste product from processed food, he added.
Dr Lim Chee Leong, an engineer with Singapore non-governmental organisation Lien Aid, said the need for affordable clean water in many rural areas in Asia "remains acute", and that villagers need solutions that benefit them in the long term.
The researchers' findings were published in September last year in the Royal Society of Chemistry journal RSC Advances, and in May this year in the American Chemical Society journal ACS Applied Materials & Interfaces.
Compounds known as pectins and flavonoids found in plants are able to absorb pollutants, said NUS Department of Chemistry professor Suresh Valiyaveettil. Where synthetic filters require multiple stages to treat water, the "multi-functionality" of nature does it in one step, he added.
But the researchers stressed that more tests are needed, and that the peel does not remove bacteria from water.
National water agency PUB is helping them test how effectively the fruit peel treats water on a large scale. If results - which are expected next month - prove promising, the researchers hope to work with non-profit groups to further develop these "fruit filters".
davidee@sph.com.sg
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