Scientists are finding potentially harmful levels of medicines, chemicals and bacteria in waterways at Congaree National Park as the preserve’s managers scramble to resolve what they suspect is a growing threat from leaking sewage and farm runoff.
The problem has become noticeable enough that state regulators placed the park’s signature stream, Cedar Creek, on a list of polluted waterways this year for bacteria contamination. The listing is the first ever for Cedar Creek, a stream recognized previously for its wild, unspoiled characteristics, according to the Congaree Riverkeeper organization.
But bacteria contamination is just one of the water quality threats at South Carolina’s only national park.
Traces of birth control medicines and drugs to control diabetes and epilepsy are among the pollutants in some of the park’s waterways, according to the U.S. Geological Survey. Farm chemicals also are being found in the water.
Geological Survey researchers outlined their preliminary findings during a recent Clemson University water issues conference in Columbia. The survey is working on a more extensive study that should be completed in the next two years.
Congaree National Park officials say they need help to protect visitors and wildlife, including the abundant fish species found in streams such as Cedar Creek.
The park, just a few miles southeast of Columbia, draws more than 100,000 visitors each year to see the vast flood plain, towering old growth trees and wildlife, including rare birds and butterflies. The 27,000-acre park also is recognized internationally for its wetlands and widely known for the glassy, tea-colored water of its creeks.
“We can’t fix the problem inside the park boundaries,” said Frank Henning, the park’s forest research and education center director. “This is an issue that requires community support.”
Pollution flowing into the park is tied to what experts say are failing sewage plants, leaking septic tanks and farm chemicals that wash off the land.
A plan by Richland County to establish a regional sewer system could help resolve some of the problem, system supporters say. The system would eliminate the need for at least three small sewer plants that serve two schools and a neighborhood. The systems have malfunctioned for years.
But the regional sewer plan has run afoul of Lower Richland residents concerned that it could cost them thousands of dollars per household and drive up taxes in an area with many lower-income families.
The dispute over whether to pursue the $13 million regional system caused County Council to slow the project recently for further assessment.
Wendy Brawley, a Lower Richland resident who has fought the regional sewer plan, said she does not want to see the park hurt, but long-time area residents remain worried about the expense of switching from septic tanks to public sewers. She questioned whether septic tanks could have that much impact on Congaree National Park.
“If there is concern by the national park about these issues about the water, and they are somehow connecting that to the sewer project, that is the kind of thing people should be talking about in advance of forcing a system on the community,” said Brawley, who said she had not heard about the recent pollution issues in the park.
Congaree Riverkeeper Bill Stangler said he understands the concern, but growing evidence shows that failing sewage plants and septic tanks are to blame.
“This is South Carolina’s only national park,” Stangler said. “It gets great recreational use. I don’t want people’s experience to be with polluted water. I want them to get the real experience they should get, which is clean and healthy rivers and streams.”
Drugged, feminized fish
Paul Bradley, a U.S. Geological Survey scientist who is studying the contamination, said that traces of hormones, mood stabilizers and birth control medicine are in the water in some of the national park’s streams and nearby rivers.
That spells possible trouble for fish and wildlife.
Pharmaceuticals flushed into the environment through sewage could be a cause of declines in some wildlife globally, according to a recent story in the Guardian, a British newspaper.
One birth control medicine found at the park – ethynylesradiol – can cause male fish to develop feminine characteristics when they are regularly exposed to even small amounts of the material. In turn, that hurts the ability of fish to reproduce, which can cause the populations of certain species to plummet.
The drug turned up last year in the waters of Muck Swamp, an easily visible section of Congaree National along the park’s boardwalk, according to the Geological Survey.
Bradley said his agency will begin checking bass and other fish at Congaree National this spring to see if males are developing female characteristics from exposure to certain compounds. He said he would be surprised if he doesn’t find the problem, since other researchers have identified the phenomenon before in South Carolina rivers.
A regional study by the USGS, completed about seven years ago, found that the Pee Dee and Savannah rivers had some of the highest levels of feminized fish in the Southeast.
The research found that more than 90 percent of the male bass in the Pee Dee River at Bucksport in Horry County showed feminine characteristics, while about 50 percent in the Savannah River near its mouth had similar characteristics.
“One should be concerned,” Bradley said. “Is it reasonable to think these kinds of compounds are contributing to it? Yes – absolutely.”
Another compound found at Congaree National, carbamazepine, also can hurt fish populations by impairing brain functions, which makes it harder for some fish to escape predators. The fish are effectively drugged and sluggish when exposed to the material, which is a mood stabilizer and anti-seizure medicine.
The Geological Survey found carbamazepine in 37 percent of the water samples at Congaree National Park last year, Bradley said.
One diabetes medicine, metformin, also was found in 41 percent of the water samples at the park last year, Bradley said. Cedar Creek was among the waters containing metformin.
Although the amounts are microscopic – measured in parts per trillion – even those amounts can affect creeks, he said. Some of these pharmaceuticals have previously been found in creeks leading into the park.
“I think it would be a little naive to assume it’s not having an effect” on the park, he said.
Bradley’s research is part of a study on how pharmaceuticals and other contaminants are affecting national parks. At Congaree National Park, the USGS has examined water quality and sediment at 14 sites, including the Congaree River, the Wateree River and Cedar Creek.
Rocky Mountain National Park in Colorado also has been examined and problems also were found there.
Perhaps of more immediate concern than the impact of chemicals on fish is the state’s designation of Cedar Creek as a bacteria-polluted stream.
The designation is noted in a periodic report, commonly called the “303d list,” of all impaired streams in South Carolina.
Streams that wind up on the list usually require cleanup plans to address specific contaminants, some of which can make people sick.
Stangler said the listing is ironic because just a few years ago, the state Department of Health and Environmental Control designated Cedar Creek as an outstanding natural resource water because of its special significance.
According to a draft being prepared for the U.S. Environmental Protection Agency, two sections of Cedar Creek inside the park have E. coli bacteria contamination at levels high enough to affect recreational use of the water.
Many strains of E. coli are harmless, but some can cause diarrhea, respiratory illnesses and pneumonia, according to the U.S. Centers for Disease Control and Prevention. E. coli also can indicate the presence of other pollutants in the water.
One site listed for bacteria pollution is at a bridge along the popular Weston Lake loop trail. The other is at a canoe access point at the end of South Cedar Creek Road below the park’s visitors’ center. The access area is a popular launch point for paddlers.
Because the creek has elevated bacteria levels, paddlers who get into the water while preparing to launch boats – or those who fall in and dunk their heads – could be exposed to possible pathogens that could cause upset stomachs.
Henning said he hopes the problem can be resolved.
“There is a concern for the safety of visitors as well as the protection of the resource,” he said. “As Lower Richland develops, this park is an economic driver for the area. It attracts visitors from across the nation and internationally.”
Through the years, water quality readings have fluctuated in Cedar Creek, said John Grego, a long-time member of Friends of Congaree Swamp.
While waste from wildlife can contribute naturally to elevated bacteria levels in water, the cause at Congaree National Park is almost certainly linked to sewage discharges and farm runoff, as well, according to the U.S. Geological Survey.
Many of the pharmaceuticals and other compounds found last year in the park’s creeks, swamps and rivers are human made. And since it’s unlikely hikers would be tossing birth control pills or anti-seizure medicine in creeks, researchers say the most likely source is from sewage.
The presence of caffeine – which is not toxic – is perhaps the clearest indicator that sewage is getting into the park’s creeks. Caffeine could come from nowhere else in this area but sewage plants and septic tanks, Bradley said.
“There is clearly transport through these major tributaries” from sewage upstream, Bradley said.
Some of the chemical contaminants may be coming from wastewater plants that are working properly, but that don’t include treatment processes for a host of pharmaceuticals. But contamination also could be coming from failing plants and septic tanks.
Data were not available last week for the number of failing septic tanks in Lower Richland near the park, but past studies have shown problems because the area is so marshy. Septic tanks don’t work well in soggy soil. Most of 47 homes surveyed in the early 1990s, for instance, experienced malfunctioning septic tanks, according to a DHEC survey. At the time, consultants were calling for a regional sewage system to stop a proliferation of septic tanks.
Sewer plant failures concerned park superintendent Tracy Stakely enough last year that he wrote DHEC about the matter. Stakely noted particular concerns about discharges from Richland County schools for fecal coliform bacteria and oxygen-demanding substances.
State records show a history of wastewater treatment plant violations from small sewage plants at Hopkins Middle School, Hopkins Elementary School and the Franklin Park subdivision.
Hopkins Elementary School exceeded legal discharge limits 16 times from August 2011 to April 2014, according to state and federal records analyzed by the Congaree Riverkeeper organization. The majority of the violations were for exceeding limits on fecal coliform bacteria, nitrogen and ammonia, Stangler’s organization found. The sewage plant discharges to Horse Pen Branch, which connects with streams that flow into Cedar Creek upstream of Congaree National Park.
Hopkins Middle School violated legal discharge limits 23 times from February 2012 to March 2014, the riverkeeper group’s research shows. All of the violations were for nitrogen, ammonia and fecal coliform, the group reported. Hopkins Middle’s sewer lagoon eventually discharges to Cedar Creek upstream from Congaree National Park.
The riverkeeper did not have records of recent violations at Franklin Park’s sewer plant, but the facility has a history of failures to meet discharge limits dating to at least the late 1990s, records show. Franklin Park’s sewer system discharges into Cabin Branch, a tributary of Myers Creek upstream of the park. Myers Creek flows into Cedar Creek at the park’s boundary along Old Bluff Road.
Farm runoff also is a concern, and Lower Richland’s rich soil historically has made it a fertile farmland.
Atrazine and metolachlor, both herbicides used in crop farming, were found in Congaree Park waters last year as the Geological Survey conducted research.
Atrazine was detected in 71 percent of the samples taken, while metolachlor was found in 44 percent of the samples.
“You do see an agricultural signature,” Bradley said.