Shocking report reveals more than half of U.S. rivers are too polluted to support life.
Experts say the it is all due to decades of pollution. The bulk of the damage has been done by agricultural fertilizers such as phosphorus and nitrogen washing from fields into waterways.
In total, 55 percent of rivers and streams were classified by the Environmental Protection Agency as being 'poor.' Only a fifth were considered in good health.
The agency looked at nearly 2000 different locations in 2008 and 2009. They looked from rivers as large as the Mississippi River to streams small enough for wading.
High levels of phosphorus – a common ingredient in detergents and fertilizers – are found in 40 percent of rivers and streams.
The EPA also found some risks for human health. In 9 percent of the tested rivers and streams, bacteria was found that could endanger health.
The toxic chemical mercury was found in fish along 13,000 miles of streams at levels exceeding health-based standards.
Scientists say another big problem is over-development. Land clearing and building along waterways has increased erosion and flooding, allowing more pollutants to enter waters.
Conditions are actually worse in the East. From Texas to the New Jersey coast, more than 70 percent of streams and rivers are in poor shape.
It's much better out west. Streams and rivers are healthiest in sparsely populated Western mountain areas. It's here where only 26 percent were classified as in poor condition.
So what do we do?
Well, experts say we have to protect and restore our streams and rivers.