- Stratton Lawrence
- Rainwater picks up countless pollutants on its way to Charleston harbor
Few animals sightings evoke as much joy and excitement as the bottlenose dolphin. Tursiops truncatus, found in tropical and temperate waters around the world, is ubiquitous in Lowcountry waters, and any Charlestonian who spends time on the deep blue sea has likely had many close-up encounters with the well-loved marine mammal.
Dolphins predate humans in South Carolina by millennia, enjoying the safe and food-abundant habitat of our estuaries and tidal creeks. In the last few decades, however, our flippered friend has fallen on hard times.
The dolphins are sick.
"Dolphins are a top-level predator," says Dr. Pat Fair, a research physiologist and the branch chief of living marine resources for the National Oceanic and Atmospheric Association (NOAA) here in Charleston. "Their extensive blubber layer accumulates pollutants like a sponge, so that combination and their long life spans make them an ideal sentinel for environmental perturbations."
Fair has spent the last five years collecting blood and tissue samples from wild dolphins, documenting the contaminants they've accumulated by eating at the top of the food chain. Of 82 dolphins examined in the Charleston area between 2003 and 2005, 20 percent were found to be diseased, while 30 percent were deemed "possibly diseased." Less than 50 percent were verifiably healthy, and many of those were female, who pass along much of their stored contaminants to their offspring during birth and lactation.
The primary illness found in Lowcountry dolphins is orogenital neoplasia, akin to the human papilloma virus (HPV) that's become widespread in the American population in recent years.
"What's contributing to this is a mystery black box right now," says Fair.
But while the exact cause of the rise in this disease remains a mystery, dolphins that died during mass die-offs had high levels of contaminants in their bodies — chemicals like PBDEs (found in flame-retardant chemicals widely used in consumer products), PFCs (used in stain repellents, Teflon, paints and polishes, food packaging, and cosmetics), and PCBs (insulating lubricants banned in the U.S. since 1977).
Industry uses compounds like PBDEs because they don't break down easily, but the environmental downside is that they bioaccumulate in the environment and may be affecting the dolphins' (and our) immune systems, making them less able to fight off viruses and disease.
"Even low-level exposure to PBDEs may produce detrimental health effects through liver toxicity," says Fair. "The amount of PBDEs and PFCs found in Charleston's dolphins are among the highest reported in marine mammals worldwide."
Your Friendly Neighborhood Dolphin
Estuaries, the places where rivers flow into the ocean and salt and fresh waters mingle, are often referred to as the "nursery" of the ocean. An estimated 90 percent of sea life relies on estuaries for some part of their life cycle, and without a healthy system of intertidal waterways worldwide, marine ecosystems — and our seafood supply — would collapse.
Dolphins are just one of many animals that mate and birth their young in estuaries like Charleston Harbor. Although some dolphins are transient, traveling up and down the southeast coast, many are year-round residents of localized areas like the Wando and Cooper rivers or the Stono estuary. Jeff Adams, an environmental researcher and GIS specialist with NOAA, found that even in tidally flushed water like Charleston Harbor, high contamination levels can be specific to a tidal creek or industrialized area.
Using fin markings like fingerprints and examining photographs from 15 years of boat-based surveys, Adams divided Charleston's roughly 800 non-transitory dolphins (an estimated 60 percent of the total population) into three groups — the Ashley/Cooper/Wando (ACW), Charleston Harbor, and the Stono. If a dolphin was sighted at least 20 times in one area, it was considered a local.
Adams found that dolphins tested in the ACW or Harbor areas possessed twice the amount of chemical contaminants as those in the Stono, where far more of the riparian environment is salt marsh rather than urban development.
"When we placed a one-kilometer buffer around the sighting areas, we found a high positive correlation between contaminants in dolphin tissue and developed land use, and negative correlations around wetlands," says Adams. "Obviously the marsh is an absence of development, plus it's a natural filtering environment as well."
As intelligent as dolphins are among sea creatures, they haven't learned to read. We can't put up signs steering them away from industrial and residentially developed areas, but we know that feeding and living in these areas causes them to accumulate dangerous chemicals in their bodies. The long-illegal pollutant PCB is now evenly spread throughout our waterways, but others, like PFCs, appear to be concentrated in areas. The question is how they're getting from our shower curtains, bed sheets, and frying pans into the harbor.
Flush, Flush, and Away
Just off the James Island Connector, the Plum Island Wastewater Treatment Plant quietly filters and releases between 18 and 23 million gallons of treated Charlestonian sewage into the Harbor each day, mingling South of Broad poop and East Side wee-wee in a cocktail party from hell. North Charleston and Mt. Pleasant also typically pump about 12-16 million and 7-9 million gallons into the Harbor in a 24-hour period, respectively. Charleston's population is expected to grow by at least 10,000 people a year for the foreseeable future, and the amount of effluent will balloon with it.
In Charleston proper, after we flush, wash the dishes, or do laundry, that water flows through one of two giant tunnels to Plum Island, carrying with it all the chemical soaps, flame retardants in our clothes and sheets, and toxins in our waste. Large items and litter are filtered out before an "Auger Monster" grinds up the remaining debris, which settles to the bottom of a grit removal tank. Oil and solids that survive that process are skimmed off the top, and air is added to aid the growth of microorganisms that clean wastewater by digesting organic materials and contaminants. Finally, sodium hypochlorite is injected into the mix to kill any remaining bacteria, and the resulting effluent is released into the Harbor. "It is cleaner than the river water and is not harmful to the Harbor ecosystem," states the Charleston Water System's informative website.
NOAA's Adams believes that chemicals like PFCs and PBDEs survive the cleansing process, but no testing of wastewater for these is required or has been conducted by the Department of Health and Environmental Control (DHEC) or the treatment plant. The correlation between development, where wastewater and stormwater pipes are most likely to occur, and high contaminant levels in dolphins would indicate that treated wastewater may be at least partially responsible for the high levels.
"There are a lot of things out there that we're not testing for, and probably should be," says Glenn Trofatter, the DHEC Water Bureau's director of compliance assurance. He explains that sewage plants and businesses are able to negotiate "maximum flows" for specific pollutants outside of their standard permits. "It's a matter of knowing that and having the basis for even looking in the first place."
- Stratton Lawrence
- Pollutants in detention ponds, at industrial sites or neighborhoods, find their way to the harbor in rainwater
Charleston Water Systems Chief Operating Officer Andy Fairey believes that the dolphins' status at the top of the food chain indicates that any number of factors could be contributing to bioaccumulation of contaminants in their bodies. He points out that prior to Plum Island's construction in 1971, raw sewage was pumped directly into the Harbor.
"We like to look at ourselves as the ultimate environmentalist because if we're not here, then the Harbor is in really bad shape," says Fairey. "Before the Clean Water Act of 1972, there was no pollution control. We've come a long way from just getting things that floated and sank out of the water to removing bacteria. I've seen our rivers go from essentially unswimmable to being much cleaner than they've been in a long time."
Fairey's right. Before wastewater treatment, the Harbor was more of a cesspool than a healthy estuarine environment. "If we wait long enough, we won't need another bridge across the Cooper," wrote one editorialist in the Charleston Evening Post in 1963, a time when the raw sewage of over 100,000 residents flowed directly into the Harbor.
We still have problems with stormwater breaching the sewer system on rainy days, and feasibly vice versa. In 1992, DHEC placed a consent order on the City of Charleston to correct leaks that allowed raw sewage to directly reach the Harbor. Over 600 miles of sewer lines run to Plum Island, so there's bound to be occasional accidents, Fairey says. But in the event of a sewage spill, neither DHEC nor utilities are required by state law to notify the public. A bill to mandate public notification was introduced to the state Legislature in 2002, but was defeated in committee. Fortunately for us in Charleston, our system runs smoother than ever before.
Even if we have a reliable sewer, in the 37 years since treatment began, we've also created countless new chemicals and products that find their way down the drain. "A lot of kids don't realize the intensive and very necessary process that occurs after they pull the handle and (their waste) goes away," says Fairey. And their parents may not realize the importance of watching what gets down there in the first place.
Before 1972 and federal clean water legislation, the largest contributors to water pollution were referred to as "point source." These were cases where a pipe ran directly into a body of water; litigation and new rules were able to quickly clean them up. The big culprit now is "non-point source," or stormwater runoff, a far more difficult factor to control.
Developing an area generally means we pave it. And when an afternoon shower falls on a parking lot, water runs across the asphalt, picking up whatever chemicals and oils it meets along the way to the closest stormdrain, which then flows into our rivers and estuaries.
Charleston County overlaps two major watersheds. In 2006, DHEC's list of impaired waterways in the county included 46 sites in the Edisto watershed, and 102 in the Santee basin. While mercury and copper contamination were both culprits at several sites, the primary pollutant was fecal coliform bacteria.
Heavy rains typically result in shellfish bed closings across the state because of the fecal coliform that almost always accompanies runoff. Although septic tank leakage has long been a suspected offender, animal waste is increasingly recognized as the primary culprit. An analysis of fecal coliform in Murrells Inlet determined the chief source was not raccoon or possum excrement, but dog. Fecal levels rose 5,000 percent in a pond on Daniel Island after one significant rainfall, a place not known for its horse and cow pastures.
Stormwater detention ponds are now a requirement at new developments, but they too often become so filthy that they do little to mitigate the problem.
"They're really meant primarily for quantity and minimizing flooding issues than for taking care of water quality," explains Dr. Denise Sanger, the assistant director for research and planning at the S.C. Sea Grant Consortium, a state agency that works to enhance the economic and ecological balance of marine resources. "The ponds probably should be pretty messy things. It's when there's a connection to the outside world that they become a problem."
Detention ponds typically have a pipe that connects to a tidal creek or river, allowing sediment to settle and the remaining water to flow out. Because Charleston is nearly at sea level, many of the pipes can't be built high enough to prevent the flow of water in both directions. Whatever settles in the ponds can then flow freely into the waterways. Because of constant tidal flushing, we haven't dealt with algal blooms thanks to increased nutrients in creeks, but with more development and paved land, it's a concern for the future.
Sanger describes tidal creeks as "the kidneys of our coast," with feeder creeks that filter and drain into larger creeks until water reaches the river, the estuary, and finally, the ocean.
"We find the strongest relationship between water quality and development in these headwaters, which are the primary nursery habitat for fish, shrimp, and crabs," says Sanger. "They're already stressful environments, as warm as bath water in the summer, and extreme shifts in dissolved oxygen and nutrient levels can really stress biodiversity and cause an ecosystem shift towards more pollution-tolerant species."
With less soil to absorb water, tidal creeks experience extreme spikes after a rain, then a rapid decrease, effectively shocking a creek's salinity, pH, and dissolved oxygen levels. Sea Grant's studies estimate that when between 10 to 20 percent of a watershed's acreage is covered by impervious surfaces (paved or built upon), these physical-chemical characteristics are adversely affected. When impervious surface reaches 20 to 30 percent, aquatic biodiversity begins to decline. Impervious surfaces currently cover approximately 14 percent of Charleston's watershed, and that percentage is far greater in highly developed areas like the downtown peninsula. As the Lowcountry's creeks are quickly reclassified from forested to suburban to urban creeks, the rivers they flow into face increasing nutrient contaminant loads.
An estimated 135,000 new homes are currently planned for the Charleston metro area. For development to minimize its effect on water quality, Sea Grant has a few suggestions: laying down gravel or "two-tire-strips" driveways that allow for more runoff to be absorbed by soil, creating vegetative buffers between yards and creeks to help slow and absorb water, and avoiding the use of fertilizers and pesticides when the forecast calls for rain. The most important thing for the average Joe, however, is sucking it up and carrying Fido's poop home in a bag.
- Stratton Lawrence
- Toxic tissue found in dolphins indicate that humans should reconsider eating fish from the harbor
Don't Swim to Castle Pinckney
Charleston Harbor is the second largest port on the East Coast, and it's unlikely it'll ever be pristine and clean until humans go the way of pluff mud. Our industrial past has left us with sediments contaminated with heavy metals, and no open shellfish beds exist on the Harbor or in its feeder rivers. Still, it could be worse. The water's not going to catch fire anytime soon, and we're fortunate not to have the same kind of factory pig farms that flood North Carolina's waterways with fecal nutrient. (Keeping industrial hog farms out of S.C. was one of the Coastal Conservation League's first major victories). We've got hundreds of scientists and a handful of organizations, government and private, who make their living monitoring our water quality.
But as we grow, the challenge is great. To meet it, the Berkeley-Charleston-Dorchester Council of Governments has commissioned a three-dimensional water quality model of Charleston Harbor, taking into account the tides, the mix of salt and fresh waters, and existing point and measurable non-point pollution sources.
"It's not like a 3-D animated game, but a very sophisticated tool," explains Ron Mitchum, executive director of council. "It looks at the entire system and lets us figure out the capacity of discharges it can handle, so we can manage growth and make sure there's no negative impact."
If a sewage treatment plant needs to expand (Mt. Pleasant will have to by 2010 — they're nearing 8 million gallons daily on a 9.7 million gallons a day permit), the model can run tests at different discharge points to examine the effect on water quality throughout the system. If applied and adhered to, fish kills and algal blooms may be a problem Charleston never has to face.
Mt. Pleasant has also taken a proactive stance, creating the position of national pollutant discharge elimination system coordinator. The job, filled by retired DHEC staffer Richard Chinnis, will be to help Mt. Pleasant fall in step with new amendments to the Federal Clean Water Act that directly address non-point source pollution. While the City of Charleston has appealed these regulations because of implementation costs and a total lack of federal funding, Mt. Pleasant may increase taxes to meet the requirements, which include educating and involving the public in litter, lawn, and dog waste cleanup programs and seeking out illegal discharges into stormwater systems. Construction and development sites will be more closely watched, and "good housekeeping" programs will be designed for city buildings and vehicles.
"There are 86 best management tasks that we'll be working to implement in the next four years," says Chinnis. "The education factor is the biggest challenge but also a big opportunity. I see it as akin to 10 years ago when nobody recycled their bottles, and now everyone does it."
Chinnis wants simple acts that you can do, like washing your car in the lawn so soap can seep into the soil instead of storm drains, to become commonplace. He sees the adoption of vegetative buffers around detention ponds and the use of stormwater filters at housing projects as promising developments that can lower bacteria counts in tidal creeks.
"Progressive lawn maintenance companies will be the wave of the future," Chinnis predicts.
Our Water, Our Responsibility
Many of the pollution problems Charleston Harbor faces today could be solved by a mass change in our individual habits. The Coast Guard responds almost daily to reports of oil sheens and spills, accidents that can be prevented by properly maintaining commercial and recreational vessels. Picking up after your animal and creating a stormwater-absorption-friendly lawn are simple steps anyone can take to keep runoff pollution at a minimum.
Other issues will take government cooperation and support. Our vast stretches of salt marsh are largely responsible for the relative cleanliness we enjoy, and their protection is vital. Development close to waterways is the most damaging, and regulations need to be in place to assure runoff is minimized. Studies predict that dredging for the new port terminal at the old Navy Base will put dissolved oxygen levels above state water standards; the U.S. Corps of Engineers currently faces a lawsuit from the Coastal Conservation League for failing to take this into account during the permit process for the new terminal.
An investigation last week by the New York Times examined 20 samples of sushi-grade tuna, finding mercury levels so concentrated that the Food and Drug Administration could take legal action to remove them from the market. Tuna is just one of many fish species on the Carolina coast showing high mercury levels in their tissue. State-owned utility Santee-Cooper currently hopes to build a new coal-fired power plant in S.C., permitted to release 135 pounds of mercury into the air each year. If mercury levels in fish rise to the point where people become afraid to eat them, our Harbor-based fishing fleet could be devastated.
Dolphins eat many of the same foods we do, including the trout and red drum that countless South Carolinians fish and consume on a regular basis, many from Charleston Harbor and its feeder creeks. The contaminants found in dolphin tissue are very likely accumulating in our bodies as well, and they're the types of compounds that stick around for decades.
"Even if production stops, there's vast amounts of these chemicals in the environment," says NOAA researcher Adams. "PCBs were made illegal in the '70s, and we're still finding them in dolphin tissue. This isn't going to go away for awhile."