Of greatest concern initially, the Keystone XL pipeline was designed to run through Nebraska's Sandhills, which lie above the Ogallala Aquifer, the main source of drinking water and irrigation for millions of people.

CNN: STORY HIGHLIGHTS

Purves is very concerned about the glaciers in the Himalayan mountains that are the main source of water for irrigation and drinking in China and India, well over 2 billion people.

FORBES: 500 Million People Will Be Displaced By Glaciers Melting In Greenland And The Himalayas

"Using these plants, we will be able to remove radioactive nuclides from the water and make it clean for irrigation purposes or even as a source of drinking water, " says Slavik Dushenkov of Phytotech.

CNN: Flower power

Groundwater is the source for nearly half of all drinking water in the world and around 43% of all water effectively consumed in irrigation.

UNESCO: World��s groundwater resources are suffering from poor governance, experts say | United Nations Educational, Scientific and Cultural Organization