Pollution can change with weather, rain

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When discussing fecal coliform, it is critical to remember that numbers can vary widely -- and are influenced by hot weather and rainfall, according to experts.

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Dr. Donna Wear, a professor of biology at Augusta State University, examines a water sample in the ASU lab.   Corey Perrine/Staff
Corey Perrine/Staff
Dr. Donna Wear, a professor of biology at Augusta State University, examines a water sample in the ASU lab.

"If the water is moving, it's always going to rejuvenate a lot faster than something stagnant," said Oscar Flite, the research director at the Southeastern Natural Sciences Academy, which has monitored bacteria levels in the Savannah River for several years.

"You looked in a lot of places we didn't look -- like creeks and pipes that could have leaks," he said, noting that the academy's long-term averages for the river involve large volumes of fast-flowing water.

Those studies, he said, place fecal coliform values in the main river channel well under the 200 colony forming unit margin, when averaged over long periods of time.

Levels can also change overnight, he said. "Keep in mind that fecal coliform in sediment can be as much as 700 times higher than overlying water, so think about a heavy rain coming through and releasing a lot more."

The academy's Phinizy Swamp Nature Park uses a constructed wetlands complex to help clean up water from the city's wastewater plant before it flows down Butler Creek to the Savannah River. Although the city's plant is well-managed, and the wetlands capably filter waste, other factors can still create elevated fecal coliform levels.

As many as 16 million blackbirds have been counted at those wetlands in a single year, he said. Such a population can create ample volumes of droppings, both at the wetlands site and other areas where they might migrate.

"A lot of what we do in our own backyards is directly related to these levels," he said. "An organic gardener using cow manure could create runoff that gets in a stream. And how many people don't pick up pet waste? All those things can affect the numbers."

Development meant to preserve streams can also help inflate fecal coliform levels, he added.

"When we build a subdivision, we cut down all the vegetation and the only place that harbors a lot of wildlife is along stream corridors, which is right there along the streams."

Frank Carl, a retired Medical College of Georgia professor and former Savannah Riverkeeper director, said the numbers collected during The Chronicle's Aug. 12 sampling blitz likely represent a good cross-section of water quality in the area -- at least where fecal coliform is concerned.

"Except for the highest three or four numbers, the results are not surprising," he said "But that doesn't mean we can't do a better job keeping our water clean."

Carl said education goes a long way in encouraging people to think about water quality. Georgia's "Adopt-a-Stream" program is one such effort, and more and more regulatory agencies are creating similar efforts.

"I don't think that we need to be afraid of our waters," he said. "We can enjoy them, but respect them for what they are."

One of the biggest challenges in monitoring programs, Carl said, is to determine what levels of bacteria in water represent normal levels and which ones represent unacceptable exposure.

"With sufficient time and money we could almost always arrive at a scientifically valid conclusion, but we generally do not have those resources," he said. "So we choose the methods that we are using to arrive at quick approximations of scientifically valid results."

Georgia, along with many other states, continues to use the 200-cfu standard for all fecal coliform, but even the U.S. Environmental Protection Agency has acknowledged that such a standard is not as reliable as other methods.

The EPA, Carl said, is encouraging states to switch to a different standard in which levels of E. coli bacteria -- a component of total fecal coliform -- would be used to identify non-conforming waters.

The EPA's recommendation is to use 235 cfu of E. coli as the standard. Because E. coli is barely 60 percent of total fecal coliform counts, it would translate to a standard of 392 cfu of total coliform, or almost twice the current standard.

"Using the current method, we generally do not get too excited about counts less than 1,000 cfu unless those counts are from an area of surface water that has no direct exposure to potential sources of contamination," Carl said.

For example, a reading of 700 in the middle of a large river indicates a substantial contamination source upstream, while a similar reading at a wastewater outfall would represent a well-treated outfall.

Improving water quality, he added, will require major institutional efforts, and also personal awareness by residents.

"If we repair our wastewater and stormwater infrastructure so that the two never meet until after the former is adequately treated, if we keep our septic systems functional, if we pick up after our pets and keep our other domesticated animals away from the streams, and if we clean up our road kill and appropriately dress our hunting kill, we can lower the fecal contamination in our water bodies," Carl said.

ABOUT THE NUMBERS

Fecal coliform levels shown here are one-time samples taken Thursday, Aug. 12, and analyzed at Augusta State University's Microbiology Laboratory using approved scientific methods and materials recommended by the U.S. Environmental Protection Agency.

The figures represent a single snapshot in time, and levels of bacteria can change frequently and radically based on factors including rainfall, temperature, disturbance of sediment and water flow.

Georgia's bacteriological standards are based on a 30-day geometric mean that requires at least four samples taken at least 24 hours apart. Those standards allow no more than 200 colony forming units of fecal coliform in freshwater streams and lakes used for recreational swimming or as a source of drinking water that requires treatment.

Higher levels up to 1,000 cfu are allowed during cooler months -- November to April.

Sites SampledTotal Fecal Coliform*
Flowing Wells on Wrightsboro Road0
Crane Creek at Scott Nixon Drive3,000
Crane Creek at Skinner Mill Road/Montclair1,100
Rae's Creek at Wrightsboro Road800
Rae's Creek at Jackson Road2,500
Rae's Creek at Scott's Way1,200
Rae's Creek at Berckmans Road2,600
Upper Lake Olmstead/Rae's Creek1,700
Lower Lake Olmstead/Rae's Creek800
Augusta Riverfront Marina100
Aqueduct Park on Rae's Creek near canal500
Grassy meadow at Savannah River shoals600
Augusta Canal at Enterprise Mill300
Augusta Canal (third level at Eighth Street)4,200
Fish Pond east side Gordon Highway1,600
Fish Pond west side Gordon Highway400
Rocky Creek at Mike Padgett near Gordon Hwy.2,100
Butler Creek at Mike Padgett past P&G600
Mayor's Fishing Hole Pond, Lock & Dam Road1,900
Butler Creek outfall to river at Lock & Dam Park2,200
Spirit Creek at Mike Padgett near scout camp500
Diamond Lakes park, upper lake500
Diamond Lakes Park, feeder stream0
Beaver Dam Ditch at Laney Walker3,600
Augusta Canal behind Davidson SchoolTNTC**
Forsythe Street Storm Drain/Savannah RiverTNTC**
Fourth Street Storm Drain/Savannah River2,600
West Dam swimming beach, Clarks Hill Lake300
Below Dam, Ga., boat ramp, Savannah River200
Reed Creek at Washington Road near Club Car1,400
Reed Creek at West Lake/Stevens Creek Road300
Reed Creek outfall into Canal at Headgates800
Euchee Creek at Washington Road600
Jones Creek at Furys Ferry Road400
Jones Creek at River Island subdivision500
Fishing pond at Blanchard Woods Park900
Lake Jean pond on Hereford Farm Road1,200
Tudor Branch at Hereford Farm Road1,100
Betty's Branch at Riverside Park900
Springlakes Lake on Columbia Road1,900
Crawford Creek at Columbia Road1,800
Community pond, Riverwood Plantation600
Woodbridge subdivision lake, Evans2,500
Windmill subdivision lake, Evans1,200
Kiokee Creek at Washington Road600
Tradewinds Marina, Thurmond Lake1,400
Petersburg Campground, Thurmond Lake600
Horse Creek in Aiken County600
North Augusta Wastewater Outfall to river500
Brickyard Park discharge to river in N. Augusta1,100

* Units per 100 mL ** TNTC: Too numerous to count

Web resources
Safety & health checklist

- Anyone with open or healing wounds should avoid contact with contaminated waterways.

- Avoid swimming in contaminated areas for 48 hours after heavy rain, or if water is muddy.

- Avoid stirring up bottom sediment, where bacteria and pathogens survive longer.

- Don't swim in areas where droppings from geese, livestock or wildlife are present.

- Anyone with immunodeficient conditions should avoid water with elevated bacteria levels.

- Anyone with gastrointestinal illness, especially children, should avoid water activities for one week.

Source: Georgia Division of Public Health


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