The United States Environmental Protection Agency (EPA) has declared that an astounding 55 percent of rivers and streams in the country are in “poor condition for aquatic life.” The results of their first comprehensive survey of waterway health reveal shrinking vegetation cover, high levels of phosphorous and nitrogen, and pollution from mercury and bacteria—none of which are all that great for human health either. These issues pose a threat not only to 1.2 million miles of waterways, but also the coastal areas, lakes and bays that are served by those rivers and streams. Additionally, as the EPA emphasizes, the polluted, unhealthy waterways include vital sources of drinking water.
The EPA National Rivers and Stream Assessment was carried out at 2,000 sites during 2008-2009, and even the potentially good news really isn’t particularly good. While 21 percent of US rivers and streams are in “good biological condition,” that figure is a sizable and rapid drop from the 27 percent estimated in 2004. The western states were found to have far healthier rivers than those in the east, but that still leaves 30 percent of their waterways in “poor” condition.
So where are these contaminants coming from? Phosphorous and nitrogen, both key ingredients in fertilizer, have long been recognized as a problem in US water health, and this latest study found a lot of it. 40 percent of waterways surveyed had high levels of phosophorous, while high levels of nitrogen were found in 27 percent of waterways. Fertilizer runoff from agricultural states not only brings ill health to rivers, streams and their ecosystems, but the effect trickles down. The Gulf of Mexico Dead Zone (over which the EPA was sued for their inaction by a coalition of non-profits) is caused largely by this agricultural runoff, which creates large algae blooms on the surface of the water that starve marine life below of oxygen.
Vegetation cover is vital to water health in many ways: it helps to remove toxins from waterways, slows down river flow during heavy rains to prevent erosion and helps to maintain a constant temperature in the water to ensure stable habitat for aquatic life. But the EPA study found that 24 percent of those 1.2 million miles has decreased vegetation cover due to “increased human disturbance.”
The levels of mercury and bacteria pollution, though found in a smaller portion of areas, pose a serious health concern for humans. In nine percent of rivers and streams there are levels of enterococci bacteria that exceeded safe levels for human health—ie., you might not want to be swimming there. Meanwhile over 13,144 miles of waterways featured levels of mercury that similarly exceed safe levels for human health, making it ill-advised to consume fish from those areas, particularly if pregnant of very young.
In publishing the study, Office of Water Acting Assistant Administrator Nancy Stoner stated: “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.” And it looks like there’s a long way to go.
+ EPA
Via NBC News