More than half of U.S. streams are polluted, with the worst conditions found in the eastern third of the country, according to a study by the Environmental Protection Agency.
In its first-ever study of shallow or "wadeable" streams, the agency found 42 percent were in poor condition, and another 25 percent were considered fair. Only 28 percent were in good condition, EPA said. Another 5 percent were not analyzed because of sampling problems in New England.
Streams running in the East, from the Atlantic coast through the Appalachian Mountains, fared the worst, with 52 percent listed as poor.
In contrast, 45 percent of streams running west of the Rocky Mountains were the least polluted, the report found.
Streams in 48 states were sampled from 2000 to 2004. The EPA plans to extend the study to Alaska and Hawaii.
The survey found activities such as farming and logging helped raise the levels of nitrogen and phosphorous in the water, said Mike Shapiro, an EPA administrator who worked on the report, in a conference call. Those chemicals promote the growth of plants and algae that gobble up oxygen. That, in turn, kills aquatic life.
At the extreme those conditions could create "dead zones" in streams, similar to one in the Gulf of Mexico where fishermen have given up catching any live fish, said Ken Cook, president of the nonprofit Environmental Working Group.
"We passed the Clean Water Act 35 years ago, and this is the first time we've taken a look at our small rivers and streams," Cook said. "It took too long."
Cook also said that the report results could be extrapolated for larger bodies of water.
"The findings are fairly consistent with what we know about the larger river system," he said.
