New Use for Sea Shells

Photo: Flickr, CC

Many developing countries, such as Vietnam are plagued by poor water quality. Millions of people suffer from illness and/or death because they lack access to clean drinking water. Local companies are unable to afford the expensive treatment facilities and techniques needed to cleanse wastewater; so, the water re-enters the groundwater supply contaminated. And the cycle continues and worsens.

All this may change now due to a previously overlooked resource.

On the banks of the Saigon River in Vietnam, researchers have just completed tests on a new way to combat water pollution that could save millions of lives in coastal cities throughout the developing world.

The exciting news about this is that there nothing hi-tech to the materials at all. The materials used are plentiful, totally natural, totally organic, cheap and readily available – the humble seashell.

The factories of Ho Chi Minh City (one of the most polluted environments in the world) was the site Stephan Kohler of the Graz University of Technology (Austria) and a team of researchers cleansed water of such toxic heavy metals as cadmium, zinc, lead and iron using only seashells.

From Discovery News:

Kohler's team has found that pouring metal and acid-laden water over a bed of crushed clam or mussel shells provides an easy fix. The shells are made of aragonite, a form of calcium carbonate (CACO3) that readily swaps out its calcium atoms in favor of heavy metals, locking them into a solid form. The shells are naturally basic, too -- when dissolved they have a pH of 8.3. [...]

The team's technique stems from work in 2003 by Manuel Prieto of Oviedo University in Spain, who first showed that shells effectively remove cadmium from water.

"The idea of using aragonite shells arose because abiogenic aragonite is not an extremely abundant mineral," Prieto wrote in an email to Discovery News. "Moreover, in the North of Spain we have a very important seafood canning industry (cockles, mussels, clams, etc.) and shells are the most important wastes of that industry."

The team’s work proves that not only can seashells be used to treat normal wastewater; but, it can also be used to cleanse real-life factory wastewater.

While developed countries can afford more sophisticated filtration system; and, probably will not convert to using seashells; developing countries (particularly coastal communities) will be able to greatly increase the quality of their public drinking water using this technique.