The underground waters in the Chaco-Pampean plain - a vast land covering over one-million square kilometres on the border between Argentina, Brazil, and Paraguay - are contaminated with arsenic. The dangerous mineral accumulated following the volcanic eruptions of the last four and a half million years. The documentary shows the operation of a water purification system designed by an Argentinean scientific team.
Arsenic has multiple effects on human health, ranging from skin injuries to cancer. Water contaminated with arsenic accumulates in vegetables and is tasteless. This property makes it particularly hazardous. The population is usually unaware of the poison contained in the water they use. The purification system, launched in 2009, exploits the property of aluminosilicate or ferrous clay - a not too expensive material, which contains high iron levels - to absorb arsenic. About two-thousand litres of water are purified in a six-hour cycle. The exhausted aluminosilicate containing arsenic is used as cement. Particular care is given to the public explanation of the purification process in order to promote the awareness of the hazard posed by apparently clear water.