From the largest urban rivers to the tiniest undisturbed creeks, nearly 2,000 locations in rivers and streams across the country were sampled by the Environmental Protection Agency (EPA) in 2008 and 2009. The findings, published in the National Rivers and Streams Assessment 2008–2009, paint a dismal picture of the state of the nation’s waterways.

The study found that more than 55 percent of our rivers and streams are in poor condition, posing health risks to fish, other wildlife and humans. Meanwhile, 23 percent were rated in fair shape, and only 21 percent were deemed to be in good biological health.

The most common problem was high levels of nutrient pollution caused by phosphorus and nitrogen – ingredients found in fertilizers and detergents that wash into rivers and streams from farms, cities and sewers. Nutrient pollution can cause algae blooms and low oxygen levels.

Compounding the pollution was land development, which increases erosion and flooding and adds other stress factors to the stream beds, according to the report, which was published March 26.

“This new science shows that America’s streams and rivers are under significant pressure,” said Nancy Stoner, acting assistant administrator of the EPA’s water office. “We must continue to invest in protecting and restoring our nation’s streams and rivers, as they are vital sources of our drinking water, provide many recreational opportunities and play a critical role in the economy.”

Aside from the threat posed to aquatic life, the EPA also uncovered potential risks for humans. The report found that bacteria “exceed thresholds protective of human health,” and that more than 13,000 miles of rivers were found to have mercury in fish tissue at levels that also exceed acceptable thresholds for human health. Mercury occurs naturally but frequently enters the environment from coal-burning power plants and the burning of hazardous waste.

“This survey suggests that, although many actions are underway to protect our rivers and streams, we need to address the many sources of pollution — including runoff from urban areas, agricultural practices and wastewater — in order to ensure healthier waters for future generations,” the study concluded.

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