If you want to get to the bottom of the issue, and how to guarantee the best source of water for you and your family, please buy a copy of my book. (foodasmedicine.ca)
In this very flat region, they are the only source of water in the jungle. (myfavouriteescapes.com)
And there are more serious problems: The release of dyes into the environment is a main source of water pollution. (npr.org)