How did the Guadalupe river become polluted?

Why does the Peace Tower bell ring every 15 minutes? Where can I get great roller blades? What first nations people lived by lake Huron? Why do you keep metal frame of a roller away from the wall corners? What are the modern day names for the rivers abana and pharpar? What effect does the gulf stream have on great Britain? What is river ganges and Lourdes? What is the largest man made lake in Australia? Where are the original Hebrew manuscripts of the books of the Bible maintained? How were the Seven Wonders of the World destroyed? What are some similarities in Mammoth Cave and carlsbad cavern? What are some interesting facts about mount Fuji? What animals in the great barrier reef eat the starfish? What makes beaumaris castle harder to attack than Rochester? What are the rebuilding dates for the San Juan Bautista? Where is the Sierra Silver Mine Tour in Wallace Idaho located? What are the two most famous landmarks that have changed because of weathing and erosion? Can animals live in the wild after living in a zoo? What ocean is located between the U.S. and Europe? What items were traded on the mediterranean trade routes?