Scientists use green, low-cost solutions to clean polluted Mexican lakes

World Today

In the capital city of the Mexican state of Veracruz, a group of scientists are rescuing two lakes from water pollution with plants that float on the surface of the lakes.

CCTV America’s Martin Markovits reports.
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Three years ago a lake in the Mexican city of Xalapa was a cesspool-a toxic soup of storm water runoff and sewage from homes surrounding the lake.

“Before we started, there were lots of micro-algae floating on the surface. There were bad odors. There were some dead fish. So it was really very polluted,” Eugenia Olguin, director of Ecology Institute of Veracruz said.

Thanks to these floating carpets of vegetation, the lake – Los Lagos del Dique – the fish are back.

They’re called “constructed wetlands”, or CWs.

Scientists at the Institute of Environmental Biotechnology in Veracruz built their wetlands, using papyrus and a plant called Galapagos leaf. Their roots filter contaminants, reduce pollution and increase oxygen levels.

Contaminants were killing the fish – now the fish are thriving.

The scientists behind this project are hoping that this system can serve as a model to other communities to help decontaminate their lakes and rivers.

Researchers anchored the plants in a bed of volcanic gravel inside plastic crates. Empty plastic water bottles keep the crates afloat.

It’s a low-cost solution to a massive problem. Olguin said it only costs $20 per square meter to build the wetlands. Similar floating wetlands have been growing in popularity in Europe, China and the U.S.