Think before you swim


Photo by Dion Ogust
Photo by Dion Ogust

Many of us head to our favorite swimming holes, those clear stretches of creek water gliding between sylvan woods that we assume are perfectly safe, certainly cleaner than a brick-littered public beach or some semi-stagnant inland pond or lake. But it turns out swimming in the Rondout and Wallkill creeks can be a serious health risk, according to the results of water quality tests for sewage-related bacteria conducted by Riverkeeper and citizen volunteers last summer and fall.

All but two of the 21 sites tested on the Wallkill from May through October had levels of bacteria exceeding U.S. Environmental Protection Agency standards for safe water. Of the 18 sites tested on the Rondout, 61 percent were unacceptable. The Esopus Creek is safer, with only two of its seven sites failing EPA safe water-quality standards.

The volunteers on the Rondout and Wallkill were “uniformly shocked by the results,” said Dan Shapley, membership and events manager at Riverkeeper who organized the citizen science program. “They felt not only sickened but also empowered. They want to see this water cleaned up.”

As part of the environmental organization’s six-year water quality testing program for the Hudson River estuary, the volunteers brought samples monthly for testing to Riverkeeper’s patrol boat. Riverkeeper tested for enterococcus, bacteria associated with untreated human sewage. (While the state Department of Conservation and many municipalities in the state test for E. coli, Riverkeeper tests for the related enterococcus because it is recommended by the EPA and because unlike the test for E. coli it can be done both in fresh and salt water.)

The bacteria cause gastrointestinal infections, resulting in a stomach ache and/or diarrhea. Fever, chills, headache, skin infections and even pneumonia are other illnesses linked to exposure to germs from sewage, which might also be infected with viruses that can cause eye infections, meningitis, encephalitis and liver infections. Young children, the elderly, pregnant women, and people with compromised immune systems are at the highest risk of contracting a chronic illness from sewage-contaminated water. In 2005-06, the federal Centers for Disease Control reported that its survey reported over 4000 documented illnesses from recreational waters in the U.S. Since people may not associate their ailments with exposure to contact with the water, according to Riverkeeper, the number is likely much higher.

In the enterococcus test, which John Lipscomb, patrol boat captain at Riverkeeper, initially developed with the help of two scientists from Queens College and Columbia University, a reagent is added to the water sample, which is placed in an incubator to encourage the growth of microbes. The sample is then exposed to UV light, which illuminates the tiny wells of the sample water if they contain the bacteria. The safe EPA threshold for the bacteria is a count of 61 per 100 milliliters of water. (It’s higher for salt water.)

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