Researchers Found an Easier Way of Removing Arsenic From Contaminated Waters

And it's the waste materials that do the work.
Mert Erdemir
A contaminated lake due to a gold mine.Cucu Remus/iStock

Arsenic is a natural but highly toxic element found in the earth's crust. Even though it's generally abundant at high levels of groundwater, human interventions such as mining and fracking increase the contamination of surface resources. As a result of this, the existence of arsenic in drinking water has long been a concerning issue

It is known that inorganic arsenic, like those found in drinking water, is much more hazardous for people than its organic form. In case of exposure, its effects may derive from poisoning and lesions on the skin that leads up to cancer. As such, reducing the level of arsenic from contaminated water is of vital importance to prevent millions of people from poisoning. However, since arsenic is a water-soluble substance, it can get very difficult and costly to remove it from the water.

A new method of removing arsenic from water

An area that has long been facing arsenic leaching into the surface water is Long Lake in Canada. The gold mine, which closed in the 1930s, has caused the contamination of the lake with arsenic and the lake has never been properly cleaned. The nearby residents have also complained about the pollution of the lake caused by the abandoned gold mine.

Recently, a group of researchers from the University of Waterloo started working on a passive treatment method that could remove almost all the arsenic from the lake water with common waste materials. The study indicates that a mixture of wood chips, leaf mulch, limestone, and leftover iron filings generates an available environment for bacterial reproduction. The generated bacteria could then absorb the arsenic by making it solid.

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During the testing process, the researchers took samples from the water and had them pass through the mixture. They eventually spotted that the arsenic concentration had decreased to a considerable extent.

This method is not only easier but also more environmentally friendly. Unlike the active treatment systems, this passive treatment uses less energy and causes less greenhouse gas emissions. Joanne Angai, who conducts the research as part of her MSc in Earth Sciences at the University of Waterloo, mentioned the cost-effectivity of the treatment by saying "Active treatment involves pumping water out of the ground, treating it, then putting it back in, whereas with passive methods you're treating the water where it is." Although this strategy of extracting toxins from groundwater before they reach surface water has been utilized in other cleaning operations, this has become the first research to prove that the method works with low pH and arsenic-heavy water.

Correspondingly, the study provides a sustainable method for the treatment of water in a more efficient, low-cost, and greener way while making it possible to easily remove even arsenic, an element that is difficult to clean, from surface waters.

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