Washington’s tap water, most of which comes from the Potomac River, meets or exceeds federal water-quality standards. But new pollutants have emerged that are not removed by current water-purification technology. Evidence suggests that the same contaminants that caused massive fish kills and deformities in recent years are linked to increases in obesity, diabetes, autism, cancer, and other disorders—and that medications and products we use every day might contribute to the problem.
Of all the natural resources in the Washington area, none is more important than the potomac river. Besides the beauty and recreation it provides, the area pulls nearly 400 million gallons of water a day out of it—about 90 percent of our drinking water.
In some ways, the Potomac is cleaner today than it was 40 or 50 years ago. Back then, people were warned not to swim in the river or eat fish from it; a tetanus vaccination was recommended for anyone who did swim there. On many days, you could smell the Potomac before you saw it.
Improvements in wastewater treatment and conservation upgraded the water quality of the river, which wends its way nearly 500 miles from its origin in the Appalachian Plateau to Point Lookout, Maryland, where it empties into the Chesapeake Bay. These efforts helped reduce major pollutants—such as nitrogen and phosphorous from fertilizers, pesticides, and soaps—that fed algae, rootless plant-like organisms that grow in sunlit water. Algae blooms—rapid accumulations of microscopic algae in water that can stretch for miles—deplete the water of oxygen and release harmful toxins. They can virtually destroy a river if left to grow unchecked.
Despite this progress, the river is not "clean." In 2011, the Potomac Conservancy, an organization that monitors the river, gave the Potomac a grade of D, a drop from the D-plus the organization assigned it in 2007. The conservancy noted that more than a third of the estimated 10,000 stream miles in the Potomac watershed are threatened or impaired.
Even so, the drinking water in the Washington area is closely monitored and meets or exceeds every Environmental Protection Agency water-quality standard. But as some of the old pollutants have been removed from the river, new ones have emerged that are not removed by current technology and may be harmful to human health, especially for the very young.
This emerging class of contaminants, called endocrine-disrupting compounds (EDCs), a variety of natural and manmade chemicals from many sources, first came to light in a dramatic way in the summer and fall of 2002 with massive fish kills along the south branch of the Potomac River in West Virginia, about 200 miles upstream from DC. Some of the contaminants are new, and others have been discovered recently because new measuring techniques permit scientists to identify EDCs in minute quantities.
Says Luke Iwanowicz, a scientist with the US Geological Survey: "Many of these emerging contaminants have been off our radar until now, mostly because we did not have the ability to detect them."
Jeff Kelble ran a fishing-guide business on the Shenandoah River, long considered one of the nation's great fishing rivers, especially for smallmouth bass. The Shenandoah empties into the Potomac at Harpers Ferry, West Virginia. Kelble remembers when fish were so plentiful that they fought over his lures—it wasn't uncommon for the sport fishermen he guided to catch 50 to 60 fish in a day, all of which Kelble released back into the river.
That changed in the last week of March 2004, when Kelble learned that fish kills had struck the north fork of the Shenandoah. From his boat, when the murky spring water was clear enough, Kelble could see redbreast sunfish and smallmouth bass lying motionless on the riverbed.
Kelble didn't know what to make of the scene. Had a poison been dumped into the river? Was this fish kill related to the kills that had struck the south branch of the Potomac in 2002 and 2003? Had a large quantity of milk somehow found its way into the water from dairy farms along the riverbank? Milk has a voracious appetite for oxygen and might have robbed the river of enough to kill the fish, but when the river's oxygen levels were measured, they were normal.
Kelble tried catching fish but had little luck. Finally, he hooked a smallmouth bass.
"We were excited at first," Kelble says, "but when we lifted the fish out of the water, we saw it was covered with red sores that looked like cigar burns, and it had lost many of its scales. I'd never seen anything like it. I have an engineering degree—I'm not a biologist—and I had no idea what was wrong. We caught a few other fish, and almost all had similar sores on them." Kelble caught more fish. "Between 50 and 60 percent of the fish had lesions," he says.
Kelble, now a conservationist with Potomac Riverkeeper—a nonprofit that monitors river quality throughout the four-state Potomac watershed—estimates that in 2004 and 2005, 80 percent of the adult smallmouth-bass population was wiped out in the Shenandoah River. The bass are back, Kelble says, but he still sees sick fish.
Vicki Blazer, a fish pathologist with the US Geological Survey (USGS), had the job of finding the cause of the fish kills. Working out of Kearneysville, West Virginia, Blazer led a team onto the rivers to collect dead and dying fish. Electroshocks in the water stunned the fish and brought them to the surface, where Blazer's group netted them and put them into water buckets to which an anesthetic was added.
As Blazer dissected scores of smallmouth bass, she was surprised to find that many of the males had characteristics of both sexes. Some 80 percent of the male fish had oocytes—precursors of egg cells produced by females—in their testes, a condition known as intersex.
Intersex among some species of fish is not unheard of but, Blazer says, "you just don't see this intersex phenomenon with bass."
Ed Merrifield, president of Potomac Riverkeeper, calls the river fish kills "the canary in the coal mine."
Our region is not alone. Fish die-offs have been reported in waterways throughout the United States. Last September, thousands of white bass died in the Arkansas River with no clear explanation. Beginning in 2008, fish kills and fish with lesions were seen in the upper James River, and lesions were seen on the Jackson and Cowpasture rivers in Virginia as well. Intersex fish also have turned up in the Great Lakes and the Mississippi River.