Major oil spill contaminating river and groundwater resources - alternative water supply?

A majoroil spill from a petroleum pipeline has affected 60 km perimeterof surrounding farms and villages

and has contaminated the nearby river as well in Mexico. 200,000 people need an alternative supply of water. How should municipalities respond to such a crisis situation? What are the alternative solutions? Can the oil plume migration be arrested and isolated to a specific regionin the aquifer ?