An inexpensive new material made of clay and papaya seeds removes harmful metals from water and could lower the cost of providing clean water to millions of people in the developing world, scientists are reporting. Their study on this "hybrid clay" appears in the journal ACS Sustainable Chemistry and Engineering.

Emmanuel Unuabonah and colleagues explain that almost 1 billion people in developing countries lack access to reliable supplies of clean water for drinking, cooking and other key uses.

One health problem resulting from that shortage involves exposure to heavy metals such as lead, cadmium and mercury, released from industrial sources into the water.

Technology exists for removing those metals from drinking water, but often is too costly in developing countries. So these scientists looked for a more affordable and sustainable water treatment adsorbent.

They turned to two materials readily available in some developing countries. One was kaolinite clay, used to make ceramics, paint, paper and other products.

The other: seeds of the Carica papaya fruit. Both had been used separately in water purification in the past, but until now, they had not been combined in what the scientists term "hybrid clay."

Their documentation of the clay's effectiveness established that the material "has a strong potential for replacing commercial activated carbon in treatment of wastewater in the developing world."