Capital News Service
ANNAPOLIS — When some Marylanders fail to pick up after their pooch, they may be doing more than irking the next-door neighbors.
Studies conducted over more than a decade in watersheds across the state have found that pets produce up to one-third of bacterial pollution in waterways near developed areas.
That’s right. Dog poop is the source of E. coli, Giardia, salmonella and other microscopic pathogens in local waters.
In extreme cases, 68 percent of bacterial pollution in the Severn River watershed has been recorded as coming from pet waste. And 87 percent of bacterial pollution in the Magothy River’s Forked Creek tributary has been traced back to pets.
The findings come from more than 50 studies by the Maryland Department of the Environment and Salisbury University tracking waterborne bacteria back to its sources. Acting as poop sleuths, scientists have been able to determine whether waste came from humans, livestock, wildlife or pets based on a bacteria’s unique patterns of resistance to antibiotics.
That’s because different antibiotics are used to treat people and various animals, said Mark Frana, professor of biology at Salisbury University, who has been involved with the studies since 1999.
“If fecal material gets into water systems, there’s an increased risk to human health,” Frana said.
In addition to carrying a host of disease-causing bacteria and parasites, untreated doggy doo is rich in nutrients that foster algae blooms and contribute to oxygen-depleted dead zones downstream, including the Chesapeake Bay.
A 1999 study by the Center for Watershed Protection found that 41 percent of bay-area dog-owners rarely or never pick up after their pets.
Most people simply don’t make the connection between pet waste and water quality, said Suzanne Etgen, Watershed Stewards Academy Coordinator at the Arlington Echo Outdoor Education Center.